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Outdoor Free Flight Forum => Peanut Scale => Topic started by: MKelly on May 15, 2017, 12:25:14 PM



Title: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on May 15, 2017, 12:25:14 PM
I've really been enjoying time with the Flying Aces Club since I got back into free flight last year.  I've got a slim hope of attending the non-nats this July, so I've decided to put together a peanut Goodyear racer in hopes of joining another event should I be able to attend.

I picked up a Shorty's Basement short kit of the Miller "Little Gem" for a song last fall, so that has become my candidate for the build.  Lasercutting on the kit is beautiful, but the wood is pretty heavy - the two sheets of 1/8" parts are 11.5 lb/ft3, and the 1/32" sheet isn't much better!  I grabbed some lighter balsa from the pile and re-cut the ribs and tip plates, saving almost 1.5g.  I am using the kit's TE as the wood is stiff and straight.

Hoping to make this a fairly quick build, as I'd like to build a Thompson racer before the non-nats as well.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on May 17, 2017, 12:37:46 PM
Wings and stab assembled.  I'm a little nervous about the wing joint - plan shows the wing butt-joined to a 1/16" plate in the fuselage frame.  Trying to decide whether I should incorporate some sort of reinforcement here...


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: FLYACE1946 on May 18, 2017, 07:55:59 PM
Really looking great so far. Wish my work bench was that neat.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on May 18, 2017, 08:06:31 PM
it's probably ok for a Pnut Mike, but I understand your concern. perhaps just taking the stub ends of the spar and TE into the I/16 plate would help without adding much weight.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Hepcat on May 18, 2017, 08:39:16 PM
Mike,
My feelings about the wing fuselage joint are similar to ozpaf john but I can't tell from the picture of the plan exactly what is involved. I suspect the fuselage to root rib joint will be good(probably too good!) but the load will be on the main spars, particularly in the inner bays.  I think gusseting the spars to the root rib would be good and perhaps a 1/32nd web between the spars in the inner bay.
John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on May 19, 2017, 10:45:43 AM
Thanks for the thoughts, guys.  Hopefully the attached plan pictures will explain my concerns clearly.  The wing is built with the LE, TE and spars ending flush at the edge of the 1/16" innermost rib.  A 1/8" root rib is glued to that.  The wing then gets glued to a 1/16" plate embedded in the fuselage side structure.

This gives me two concerns:  first, that the 1/8" root rib is a weak point, likely to split between the wing and fuselage upon hard landings because there is nothing crossing the grain to prevent cracks from starting.  Second, there is no structure inside the fuselage to reinforce the wing attach plate, so any bending moments are resisted only by the 1/16" plate and 1/16" square uprights - easy to collapse the fuselage sides.

My thoughts for corrective action are to carry the LE and spars through the root rib and into the fuselage about 3/16", and put some reinforcing gussets inside the fuselage at the LE, TE and spar intersections to spread loads down the sides of the fuselage into the crossmembers.

Can't carry the wing structure across the fuselage because it would interfere with the motor.

Thoughts?

Meanwhile, I built the fin and cut/sanded replacement wheel pant parts from lighter wood using the hard kit parts as templates.  The new pants save 2.5g over the kit parts (before sanding to shape).

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on May 19, 2017, 08:03:28 PM
That should work a little better Mike. The reinforcement plates picking up the LE, spar and TE extensions would add a fair bit of strength if cross grain to the 1/16 plate which is what I imagine you mean.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on May 22, 2017, 11:36:14 AM
John,

Yes, that's what I was planning, small vertical reinforcements that would run cross-grain to the wing attach plate. and reinforce the uprights below the wing attach plate.

That said, I built the fuselage sides this weekend.  I used fairly stout 1/16" square stock for the uprights that attach to the wing plates and the resulting structure seems pretty sturdy.  I think with the reinforcements it will be satisfactory.  Pic shows the fuselage sides, and the 1/8" root ribs being glued to the wings after notching them to allow the spars and LE to carry across into the fuselage.  Information on this plan is pretty sparse, but after comparing this one to the Walt Mooney Little Gem plan I see why the 1/8" root ribs are necessary - the fuselage curves a bit so the 1/8" ribs get trimmed to allow a flush fit the full length of the root chord.

Next step is to drill holes in the attach plate for the spars and LE, then get on with assembling the fuselage.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on May 23, 2017, 10:31:10 PM
Fun with magnets!  This is the first fuselage I've built on the magnet board.  Overall it's going pretty smooth, although I think I want to embed smaller magnets in some of my poplar blocks.  The big rectangular magnets have a fair amount of power, and can either push the other magnets (and your parts) around or crush wood between magnets if you're not careful.  I've got a lot of the small round magnets - looks like I'll finally have a use for the Forstner bits I bought.

I cut some foam blocks for the two center bays to help keep the fuselage square throughout assembly.  I cut the corners off them to keep from gluing them in place when adding the crossmembers.  I also bent the landing gear wire, glued up the wire/former sandwich and glued that assembly into the fuselage.

I love these little metal Zona L-squares - perfect for aligning components, and with a magnet you can stick them anywhere you need them and they'll stay put.

Mike






Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: TRuss on May 23, 2017, 11:54:02 PM
I generally like building with magnets, it's dead flat and easy to jig stuff, but they do present their own challenges do.  Polarity can be tricky.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on May 24, 2017, 03:42:25 PM
Got the fuselage crossmembers installed and added the lower formers and stringer while everything was jigged up on the board..

I added 1/16x1/8" doublers from light balsa to the uprights at formers 3 and 4 (basically front and rear of the cockpit.  This made the fuselage sides very rigid - should be sufficient to handle loads coming in from the wings.

Fuselage frame as shown weighs 2.8g.  Still have to add all the upper structure.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on May 26, 2017, 03:36:51 PM
Installed the upper fuselage formers.  I replaced the kit parts with lightweight 1/16" sheet.  The turtledeck formers are cut from sheet spliced together on a diagonal, excess cut out from the middle, and sanded down to about 1/32" thickness.  Replacing these parts saved about half a gram.

For the forward sheeting, I made a paper template, cut the balsa, test-fit it and trimmed the right edge to fit as good as I could get it, then glued the right edge to the framework.  After that set, I glued the sheeting most of the way across the formers, wetting it to make it easier to wrap, and leaving the last 1/8" unglued on the formers.  After again waiting for that glue to set, I trimmed and sanded the left edge to fit, then glued and taped that.

While that dried I put in the turtledeck stringers, stripped 1/20th" wide from 1/32" sheet.

Through all that I only managed to put my fingers through one longeron...twice.  Fortunately it's at the nose, where there will be carved balsa for the lower cowl.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on May 31, 2017, 04:28:15 PM
Not much progress this week due to other commitments.

I haven't had much luck finding documentation on this airplane via the internet - just a few relatively small black and white pictures and an OK multi-view drawing. Yesterday I received in the mail a copy of the 1968-71 air racing annuals by Reed Kinert - this had several pictures of Ole Tiger which helped me understand the shape of the lower cowling and showed the instrument panel.  Lots of other interesting airplanes in there as well, along with some fascinating descriptions of the modifications racers were making to try and get a competitive edge.  I see several potential projects in this book...

Hope to get back to building this evening.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on June 01, 2017, 06:23:33 AM
That's a handy way of doing the turtle deck formers with opposing diagonal grain. Probably a better way to do all curved formers to keep them strong - especially after they are notched for stringers.
Also a practical way to approach the nose sheeting - I suppose it's a very old method but it's new for me.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 02, 2017, 12:13:23 AM
John,

Can't take any credit for the former approach - I stole it from Jim Longstreth's Sweet Patootie plan (2001 Flying Models article).  It's light, and it works well where the formers sit on crossmembers.

Glued the cheek blocks on last night and squeaked in an hour of whittling and sanding this evening.  Assembled the noseblock and used a length of tubing to set in some down and right thrust.  The plans are silent on thrust angles, so this is my TLAR approach...

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 04, 2017, 12:30:35 AM
Spent some time today working on the "canoe" that makes up the lower cowl.  The plan just says to carve blocks of foam and glue it to the provided balsa keel, without giving any outlines or templates for what the cross-section or plan view looks like.  The pictures I've found help some, but they are all black and white, and the details of the shape don't show clearly, especially how the carb air scoop fairs into the canoe.  Best I can tell, the canoe has nearly-vertical sides and a slightly convex bottom that rides up the sides of the carb air scoop.

Armed with vague info and suppositions, I made a paper template for the plan view of the canoe, cut 1/8" and 1/4" sheet using the template, fit that against the lower fuselage and keel, trimming and sanding until it all fit together reasonably well, then glued it together.  Next I made another template and used it to cut sheeting for the sides of the canoe from soft 1/16" balsa, trimmed the sheets and glued them to the 1/8" and 1/4" top and bottom plates.  I purposely did not glue any of this to the fuselage yet, which allowed me to sand the assembly without having to work around the gear legs or worry about crushing sticks or sheet on the fuselage.  After sanding till it looked about right I cut away almost all of the 1/8" plate, gouged out a good bit of the inside of the 1/4" plate and cut away as much of the keel piece as I dared.  Final weight on the canoe assembly as glued onto the fuselage is 1.15g.

I also cut out replacement parts for the cheeks from lightweight balsa.  The kit cheek parts were almost 5 grams - replacements are about 2.5g.  A lot of this will get sanded off, but the fuselage is pretty nose-heavy already and the bare airframe is pushing 10g, so it seemed worthwhile.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 11, 2017, 12:44:55 AM
Another slow week on Ole Tiger.  Carved, sanded, fitted and hollowed the cheek blocks.  Reduced their weight to 1.4g.  Still need to trim them for where the wing will run through.

I'm starting to feel rather weight-obsessed with this model, as it seems really heavy for a peanut (13.5g structure  weight at the moment including the wheel pant blanks).  Lots of sanding still to do.

Regarding the cheeks, I'm thinking through whether to add them before or after covering the fuselage.  Seems like it might look better in the end if they are added before covering, but that seems like it would make covering the fuselage a lot harder.  I also think a little sheeting at the lower intersection of the cheeks and fuselage will be necessary if the cheeks are added before covering, to give a good surface for attaching the tissue.

Kinda losing steam on this build...

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: USch on June 11, 2017, 04:31:55 AM
Love these little racers....must build one myself next winter. Keep at the nice work Mike, we are curious how she fly's.

Personally I would fit the cheeks before covering. It might be just my opinion, but stuck on later always looks like that, stuck on, not integral part of the frame.

Myself I would open up the nose block former, maybe to diamond shape. These models are already small and the bigger the hole in the front former, the better access you have to change motors, use a blast tube etc. Just my 2-cent's worth  ;)

Urs

PS: the diagonal cut formers will be part of my future builds, thanks for that!



Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on June 12, 2017, 03:47:16 AM
I think Urs idea of adding the cheeks to the structure before covering will be neater.

Would it be possible to add a thin light flange to the cowl as a tissue anchor where there is no balsa on the main fus structure?

Happy building.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 12, 2017, 05:58:02 PM
John, Urs,

Agree that the model will look better if the cheeks go on first.  I added some light sheet to either side of the fuselage to form a "tissue anchor" as John suggested.  Will mount the cheeks after mocking up the wings and trimming for the wing-cheek intersection.

Rearranged the building area this week to make the room work better for the family.  The work table ended up against a wall, so I added a magnetic whiteboard above the building board.  Makes a good place to hang the plans for quick reference, and also gets the magnets off the building surface when not needed.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on June 12, 2017, 07:45:57 PM
it's a complicated little model in the nose area Mike. Pity you couldn't just add a composite FG nose cowl, cheek cowls intakes etc. :)
The cheek cowls attachment will be stronger with your additional inlaid sheeting, better than my idea of flanging the cowls.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 12, 2017, 09:54:43 PM
Yep, up front it's starting to look like a lumberyard after a tornado.  We'll see if it finishes up as more of a Tiger tank than 'Ole Tiger...

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: FLYACE1946 on June 13, 2017, 10:25:58 AM
Mike this project is moving forward, seems like you just made a huge positive turn getting past the hard part. You will finish in fine fashion.  I am looking forward to the flights ahead for this racer.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 13, 2017, 11:59:10 PM
Thanks Allen,  I'll get this thing done yet.

Got the wings sanded and fitted today.  The root rib is very long, and because of the way the fuselage sides curve the root ribs have to be trimmed to match that curve.  This has to be done on an angle to allow the wing to sit flush at the plan-specified dihedral (3/4" root-tip).  To facilitate this, a 1/16" root rib is installed using a dihedral gage, an additional 1/8" root rib is glued in, then the 1/8" root rib is trimmed to match the fuselage sides.

When I built the fuselage sides I marked and match-drilled holes for the spars and leading edge.  On the wings, I left the LE and spars long at the root so that they could carry through the fuselage sides.  I cut the 1/8" root rib oversize, trimmed it to fit inside the spars and LE, then sanded the wing to bring the root rib profile parallel with the rest of the wing top and bottom surfaces.

With the fuselage and wing panels assembled and sanded, I used a square needle file to open up the holes in the fuselage just enough to pass the spar and LE into the fuselage sides.  After checking that the spars were perpendicular to the fuselage centerline from a top view, I used a divider to scribe the fuselage profile onto the root rib.  The wings were then taken off the fuselage and jigged onto the building board with the tip raised 3/4" for dihedral.  I carved almost to the profile line, then used a right angle sanding block to sand to the profile line.  A couple of iterations of fitting and sanding got the wings to match the fuselage sides pretty well with the right dihedral.  A little bit more fill is needed at the TE - I've glued a couple of short lengths of soft 3/32" sheet to the root at the TE and will trim that tomorrow.

Once that's done it's on to trimming the cheeks to clear the wings...

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on June 15, 2017, 06:13:25 AM
Good solution Mike. I like the way you carefully broke the problem down into achievable solutions.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 15, 2017, 11:21:35 PM
Thanks John.

After fitting the cheeks around the wings it seemed like there should be something supporting the tissue where the cheeks rest against the wing.  I added a fillet on top and a bit of sheet to the lower surface of the wing to provide a more positive mating surface.  This should (hopefully) also help avoid wrinkles at this joint when covering.

With the cheeks and wings fitted it's time for the obligatory bones shot.  After what seems like weeks of carving and finagling this feels like a bit of a milestone...

Still have to carve and sand the canopy top and wheel pants, but I'm now motivated enough to start collecting images for the tissue.  Found the STP, Bardahl and Champion logos on the web.  I've got a semi-useable picture of the "Ole Tiger" lettering and tiger that I may be able to clean up enough to use.  The original Shorty's Basement kit for this came with a decal sheet, but I bought a short kit on clearance that did not include that decal sheet.  If anyone has it and could share a scan of it, or if anyone has any color pictures of the sponsor decals or "Ole Tiger" logo I'd be most appreciative.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Mark Braunlich on June 16, 2017, 09:55:21 AM
A couple of pics of Denny Sherman's "Little Gem" before purchased by Bob Downey, repainted and renamed "Ole Tiger".  Photos by eminent air race photographer, Robert Pauley.
Both photos reportedly from 1957, the first at Danville, NY, the second at Ft. Wayne, IN.   Note change in wing planform and tail surface shapes.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 16, 2017, 04:09:30 PM
Great pictures - thanks!  I love the blue & gray color scheme in the Danville picture, and I like the look of the airplane with the straight wings and rounded tips.  Comparing the two pictures it looks like the Ft Wayne photo has the new wings and tail.

Thanks again,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 16, 2017, 10:45:50 PM
More carving and sanding - got the canopy top and wheel pants done today, and added a strip of 1/8" to the lower longeron between the gear wire and the former behind the cockpit to replicate the lower fuselage contour.  Couldn't resist another couple of frame shots - the pants make it look fast!  Not bad progress for a month into the build (for me, anyway).

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: BG on June 17, 2017, 03:20:52 PM
looks great! what is here weight?
B


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 17, 2017, 04:43:46 PM
Thanks!  Kinda chubby, 12.4g as pictured.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Bingo Fuel on June 18, 2017, 01:28:48 PM
Hi Mike,   It sure looks great.  You might want to consider the all black and white version as it looked in very late 50's and early 60's.  It won the first Reno race in 1964 with owner pilot Bob Porter at the controls.  Still always number 14.   Many of these Goodyear and Formula 1 models end up nose heavy so you might consider moving the rear rubber hold location back another bay. Just an idea.  Can't wait to see it finished.  Bingo


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Bingo Fuel on June 18, 2017, 01:37:10 PM
Mike.  The lower cowl is the same on the black and white version as on the "Ole Tiger" version.  Bingo


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 18, 2017, 05:41:34 PM
Bingo,

Thanks for the info - googled around a bit and came up with three pictures of #14 Little Gem in 1963-64 on the Sherman Aircraft Sales website (http://www.shermanaircraft.com/our-history/ (http://www.shermanaircraft.com/our-history/)). 

I like the black and white scheme a lot.  One of the pictures shows the carb air scoop and lower cowl quite nicely, clearly showing that I have it completely wrong...  rather than the lower cowl rising up over the scoop as I've done it the scoop actually fairs out to meet the fuselage sides with a smooth, slightly rounded lower surface.  No worries, a little surgery and some more carving and sanding and all will be well.

The pictures show the sides and lower wings pretty well, but I haven't yet found any pictures that show the upper wing.  The pictures also show that at the race in 1964 the team had added lettering and sponsor markings that weren't on the relatively clean 1963 picture.  I'll keep looking to see if I can document that better; if anyone knows of pictures or drawing that show the upper wing and details of the race day markings I'd much appreciate a copy or link.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Mark Braunlich on June 18, 2017, 10:10:28 PM
From the Society of Air Racing Historians page on FB.  Bob Porter in Little Gem at the pole position for '64 Reno start.

https://www.facebook.com/photo.php?fbid=10203690211438675&set=oa.784967138277069&type=3&theater


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 18, 2017, 10:49:30 PM
Thanks Mark!  That's on a closed page, so I've put in a request to join so that I can see the picture.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Mark Braunlich on June 19, 2017, 11:28:28 AM
Sorry 'bout that!


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 19, 2017, 05:31:40 PM
Mark, thanks much - that is a perfect picture!  Looks like the top wing is marked just like the lower wing, with 14 on one side and the N-number on the other.  This scheme should be relatively easy to print on tissue (but I may need the XL black cartridge...).

Thanks again - that pic helps a lot!

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Bingo Fuel on June 19, 2017, 11:16:45 PM
Great pic Mark.  That is Denny Sherman hanging on to the tail.  Bingo


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 23, 2017, 05:34:11 PM
OK, so I spent the week fixing the canoe (lower cowl).  I cut off the incorrect canoe, leaving the 1/32" center plate as a reference to locate the parts for the corrected canoe.  I decided I might as well improve the hodge-podge of sheeting I'd installed to provide anchors for covering, so I took out the sheeting and stringers back to the diagonal running in front of the wing plate.

I cut and fitted an upper plate out of 5lb 1/8" sheet using a paper template for a guide.  That got sanded a lot to round the fuselage profile under the cheek pods - more like the original.  Once the sanding was done I cut out most of the center area of the plate to reduce weight and keep everything clear of the motor.  I added and trimmed a 1/16" plate below the upper plate to provide a backstop for the sheeted sides.  I also trimmed about 3/16" off the vertical center plate to make room for the new lower plate.

Next I fitted a lower plate from 5lb 3/16" balsa, hollowed out on the inner side.  I put small triangular plates on the upper surface at the leading edge of the plate and cutouts aft of the scoop so the sheeted sides could begin above the scoop, then extend down the sides of the lower plate further aft.  I cut and fit a paper template for the side sheeting, then cut the sides from light 1/32" sheet and glued them to the plates.

Once that was dry I added a frame of hard 1/16" square stock to form the front of the scoop, then fitted strips of 3/16" sheet on either side of the scoop running about 3/4" back on the sheeted sides to form the side fairings for the scoop.

Finished up with an hour or so of shaping and sanding.  I'm happy with the end result - looks much more like the pictures than what I'd built before, and with the new structure the fuselage is 6/10ths of a gram lighter and a bit stiffer!

During various glue-drying interludes I've created the artwork for the flying surfaces.  Still have to do artwork for the fuselage, but covering may commence this weekend.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on June 24, 2017, 07:39:23 PM
Nice work Mike. Building the cowl/front area on the full size must have been fun.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 25, 2017, 09:35:19 PM
Thanks John.  From what I've read the airplane flew with both aluminum and fiberglass cowls.  My sheet-metal skills would not be up to forming those cheeks...

Still working through details before covering.  I've struggled before getting accurate and durable joints for LG strut fairings to wheel pants, so I thought I'd try something different.  I attached the pants to the LG wire, using a small u-shaped brad from scrap wire to tie the vertical part of the LG wire to the pants (the laser-cut parts had two tiny holes for this purpose; I replicated them in the lighter parts I cut) and secured the pants to the wire with tape.

I took a smaller x-acto blade, layed it on the LG wire, and cut a slot in each pant where the LG wire intersects the pant.  Then I cut new strut fairings from 1/32" sheet using the kit parts as a guide, but adding a v-shaped tab on the pant end.  I glued two additional pieces of 1/32" sheet to the lower side of the strut fairing leaving a slot for the LG wire.

The tab on the strut fairing got pushed into the slot on the pants, and the top end of the strut fairing got trimmed and sanded to match the fuselage. Once I was happy with the fit I sanded the strut fairings smooth and rounded the front and rear edges.

This feels pretty solid even without glue, and the pants look to be aligned well.

On to the next bit of minutia...

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 26, 2017, 04:35:34 PM
Mark Braunlich,

Thanks again for the link to the Society of Air Racing Historians Facebook page - added today and spent about three hours perusing all the pictures, posts and comments - fascinating!

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 26, 2017, 10:09:44 PM
Turned wheels and a spinner mold today.  Wheels are good to go, so glued in aluminum tube.  The spinner is still a bit oversize compared to the noseblock, but the light's not good enough in the garage to finish it off tonight.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 28, 2017, 05:04:33 PM
Fun with baby boomer toys!

Dug out the Mattell Vac-U-Form that I got at a flea market in the '70s - hadn't used it in probably 25 years, but it still heats up and pulls vacuum.  Rummaged around and finally found a pack of .015 styrene from my high school plastic modeling days.  Took a couple of tries, but I got a decent pull on the spinner, trimmed it up and it's ready to go on the propeller.

Also brushed some balsa fillercoat on the sheeted areas, cheeks and pants, then sanded that smooth.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on June 28, 2017, 07:09:07 PM
The spinner looks spot on Mike - you and AUD Mike make vacuum forming look simple. What did you do in plastics at high school?

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 28, 2017, 09:01:54 PM
As a kid I built many plastic models, mostly airplanes.  I still have a trunk full of unbuilt/partially built kits from the '70s and '80s, but I've probably only finished one plastic model in the last 30 years.  Now using the tools (and some of the paint!) from that era to build balsa...  Last use of the Vac-U-Form I can remember was to make a canopy for a peanut Sea Fury (from Model Builder plans) back around 1986.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: FLYACE1946 on June 28, 2017, 10:33:13 PM
Mike I know this spinner is great, and the entire project is a masterpiece. Thanks for sharing.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 29, 2017, 05:00:37 PM
Thanks Allen.  BTW, in the '65 Homebuilt annual you loaned me there is a nice picture of "Little Gem" on the starting line at Reno - looks like it was taken just after the pic Mark shared here.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Fudo Myoo on June 29, 2017, 05:23:58 PM
That's looking rather lovely, look forward to seeing it completed. Those cowls and cheeks etc would have probably finished me off as stuff like that is beyond my current skill set.

I remember the first time I saw pictures of the real thing, I totally blanked on just how tiny it was until I saw the next picture with the pit crew guys next to it, I think my jaw must have dropped a little!


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on June 29, 2017, 09:39:02 PM
Thanks! Yes, the midget racers are quite tiny.  What always strikes me is seeing how huge the pilot's head appears, just about filling the canopy.  Quite a contrast to the warbirds.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 06, 2017, 03:21:32 PM
Progress is slow with visitors for the holiday.  Work continues on the tissue templates.  Originally, I was going to print the fuselage sides as a single image, with a seam between the left and right sides at the top.  The more I thought about this the less I liked it, so I decided to split the covering at the line between the black lower half and the white upper half.  I wrapped some cheap gift wrap tissue over the turtledeck and upper cowl, marked the edges by dragging a soft pencil over the structure, then scanned the resulting patterns to make layouts for the turtledeck and cowl graphics. 

Pictures show test prints (on regular paper) of the graphics - I did the same blue alignment lines at each rib/LE/TE point as I did for the Waco graphics.  Makes it much easier to get the tissue about where you want it when covering.

Graphics are all done in Powerpoint, built up over scanned plan images.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 09, 2017, 11:49:16 PM
Got started on covering today.  Decided to begin with the wheel pants, since that was the worst part of covering the last model I built (Waco SRE).  Printed rectangles of black on Esaki, then chalked the line down the center of the pants white.  The photos show how much the chalk brings out the white - compare the stripe to the border around the rectangles. 

Pants were covered wet.  I applied glue stick to the pants, tacked the tissue down and got it straight, stretched it around the top and bottom, trimmed it, then used thinned white glue to seal the edges down.

Much easier than the Waco landing gear, and it looks pretty decent.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on July 10, 2017, 09:28:43 PM
Are they wet covered Mike? They are very smooth.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 10, 2017, 11:18:35 PM
John, thanks - they are indeed wet covered. 

Chalked some more tissue today and got the underside, upper cowl and turtledeck covered.  These pics really show how much the white chalk changes the appearance of the tissue.

I decided to cover the cheeks separately, then attach them to the covered fuselage.  The more I handled the fuselage the more concerned I got over the likelihood of breaking something while attempting to stretch tissue over the cheeks.  Given that the colors intersect at the joint between the cheeks and fuselage I think it will look OK if the cheeks are attached after covering.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on July 11, 2017, 03:20:02 AM
The chalking has made all the difference Mike - very impressive. Those details on the fuse covering look spot on.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 14, 2017, 11:22:38 PM
One step back, two steps forward...

After covering the turtledeck I was mocking up the black side tissue and noticed that the race number didn't align with the turtledeck text like photos of the actual aircraft.  After much peering and muttering I determined the text was too large, extending too far back towards the tail.  While looking at that, I noticed that on the right side of the plane the city name was painted in all caps (unlike the left side). Thought about leaving it, but I knew it would bug me so I wet the glued edges of the tissue and pulled it off. 

Spent most of my modeling time on Thursday revising the graphics.  The scanned photo graphics I'd used previously weren't any good for the right side, and didn't look very good when scaled to the correct length, so I hunted through the font packs and played with the text to re-create the hand-painted lettering as best as I could, printed a couple of test shots to check the look, then printed up some new tissue for the turtledeck.

In between looking at fonts I took a break, covered the glare shield with black tissue and edited up a photo of the instrument panel.  The panel photo is from "Ole Tiger" as raced in '68, but I bet nobody will complain...

Today I got the revised tissue on the turtledeck, then covered the wings.  Tonight I'll spray them and pin them down to shrink overnight.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: BG on July 15, 2017, 09:23:30 AM
Looks great Mike.
What printer are you using? how does the ink standup to water and alcohol?

thx
Bernard


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 15, 2017, 02:42:29 PM
Bernard, thanks!  The tissue is printed using an Epson 7610 printer with dura-brite inks.  The ink seems to hold up well to water, white glue and dope - I don't use alcohol for covering.  I've seen others state that the ink holds up with alcohol during glue-stick covering and shrinking, but I have not yet tried that method.

The colors inks proved very tough when I used them on my Waco SRE.  On this one I've found the black will smudge a little if you rub it hard when wetted - I've just adjusted my technique to use a little less white glue/water when tacking tissue down and to resist "adjusting" the tissue via direct contact when shrinking with water.

Hope this helps...

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 17, 2017, 09:36:58 PM
Covering continues.  Stab and fin are covered.  For the stab I put the printed and chalked tissue on a frame and shrank it again.  I used Elmer's glue stick to tack the stab to the tissue while still on the frame, then cut it out, trimmed to a slight overlap, sealed the edges with white glue/water mix and repeated the process for the other side. 

I cut a couple lengths of scrap wood to make a washout jig for shrinking the wing tissue - pinned them over the plan with 1/8" shims under the outer TE on each side, then wet the wings and used scrap balsa and pins to hold them down while drying.  I'll use the same jig when I dope them.

I got the black tissue on the fuselage sides (applied dry), then covered the carb scoop and canoe area with a single dampened piece of tissue.  That was one of the hardest bits of covering I've done, and there is a little hazing on the black tissue where it was really stretched and rubbed to get it glued around the scoop and up the canoe.  If it still looks smooth after I've shrunk the fuselage I'll touch it up with black pastel prior to doping, otherwise I guess I'll have to pull some of it off and re-apply in multiple pieces.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 18, 2017, 10:49:30 PM
Covered the cheeks and rigged the landing gear today.  The cheeks were a real challenge - after several failed attempts at stretching the tissue around I gave up and covered each with three strips lengthwise.  Thanks to the black color the seams are not too obvious so I'm going to go with it.

The LG strut fairings will get covered after installation so I can wrap the tissue over the LG wire and hide it.

I also chalked over the sides of the canoe with black chalk - this did a good job of hiding the fading from stretching the printed tissue.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on July 19, 2017, 03:48:25 AM
That's pretty good in my books Mike. That colour scheme is eye catching and all the printed logos really set it off.
I'd be proud to get any where close to this level.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Sky9pilot on July 19, 2017, 09:48:01 PM
Mike...amazing skill with the tissue application, not discounting the great craftsmanship on the build and instrument panel.  Outstanding!
Tom


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: John Webster on July 20, 2017, 06:45:03 AM
That looks great. Really nice printed tissue.

Are you going to make the canopy from a flat sheet?


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 20, 2017, 12:08:11 PM
John, Tom, John,  thanks! 

Had to fit the wings and cheeks today to align tissue for the noseblock, and couldn't resist mocking it up and taking a few pics.  John W, the canopy will be cut flat with, with the frame overlayed with bond paper covered with tissue to match the rest of the finish - pics of template attached.

It's looking good, but it's no lightweight - 16.2g as pictured.  Still has to get doped, add the pilot, canopy, tailwheel and prop and final balance - I'll be lucky to get away under 20g.  Balance at the moment without the prop is just about right - here's hoping the prop and rubber won't shift it dramatically one way or the other.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Konrad on July 20, 2017, 12:37:11 PM
Covered the cheeks and rigged the landing gear today.  The cheeks were a real challenge - after several failed attempts at stretching the tissue around I gave up and covered each with three strips lengthwise.  Thanks to the black color the seams are not too obvious so I'm going to go with it.

The LG strut fairings will get covered after installation so I can wrap the tissue over the LG wire and hide it.

I also chalked over the sides of the canoe with black chalk - this did a good job of hiding the fading from stretching the printed tissue.
Mike your work is exquisite!
WHAT SEAMS? :o They look fantastic!

I'm still trying to learn how to cover  with a minimum of wrinkles and tears. But I'd like to ask what is this "chalk"? Are these pastels added to the back of the tissue to bring out the color. Or is it used to allow the tissue to slide around a bit, aiding in the covering of compound surfaces?

Is there a detailed "How To" on Hip or anywhere else that goes into the covering process in detail?

Thanks,
Konrad



Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 20, 2017, 12:59:27 PM
Thanks Konrad - the camera hides many warts... 

Chalking modifies the color and/or opacity of tissue.  This is the second model I've tried it on - for this one I'm primarily trying to get a bright, opaque white to set off the black markings.

Scot Dobberfuhl did a great tutorial - it's posted on the Easy-Built site at http://www.easybuiltmodels.com/chalk.htm (http://www.easybuiltmodels.com/chalk.htm) (along with several other good tutorials).  I'm using a set of Sargent artist's pastels - picked it up this spring at Hobby Lobby for about $15 with their usual e-mail discount coupon.  I suspect it will last through my lifetime...

Cheers,

Mike



Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Konrad on July 20, 2017, 02:28:58 PM
Thanks Konrad - the camera hides many warts... 
...

Cheers,

Mike


Mike, you're too modest. I know from my posting that the camera brings out the warts. This is not only because of the lighting but also that the image on the screen is often 3 to 4 times larger that the real life 3 diminutional subject.

Thanks I'll look into that link, in detail

All the best,
Konrad


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Sky9pilot on July 20, 2017, 10:12:33 PM
Loved the mockup!!!! Great looking model!
Tom


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: ZK-AUD on July 21, 2017, 04:18:46 AM
 Well if you built it and it needs to be 20g then so be it - must be a heavy design!  Just a  different strategy - hard for the Lacys and Fikes to compete when they're shredded on the floor!  Great job mate - love your woodwork.

Cheers, Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 21, 2017, 01:38:28 PM
Thanks Mike.  The thing that strikes me is how heavy this would have been had I used the 12-lb/cuft balsa the kit supplied for the formers, ribs, spats and cheeks. 

The model has a fair amount of wing area (just over 51 square inches), so it can afford to be a bit heavier than many peanuts.  The guidelines in Bill McCombs' book suggest max structural weight (RTF without motor) should be less than 17g.  In the end, it will be what it is and I'll just have to see what performance I can coax out of it.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on July 21, 2017, 07:56:44 PM
I doubt that you will have too many problems Mike. it's still going to be close to the magic 0.5gms/sq inch rule. (love the mixed units).

It is truly outstanding to my eyes.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 26, 2017, 07:52:36 PM
This one's for those who like watching dope dry...


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: FLYACE1946 on July 26, 2017, 11:10:23 PM
Great to witness the process. I have a lot of scrap balsa left from lazer kits and now I know why I saved all that wood. Think this racer ought to go far.

Very nice Mike. Seriously nice.   


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on July 27, 2017, 07:51:05 PM
What is the reason for the blue tape Mike?

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 27, 2017, 08:53:16 PM
John,

The blue tape is just holding down some plastic wrap I put over the standoff sticks to keep the doped tissue from sticking.

I'm going to give the dope several days to cure with the flying surfaces restrained in hopes of precluding major warps.  In the meantime today I played with propellers.  I've got two candidate props for this model - a 5" Tern and a 5.5" North Pacific.  The Tern did a great job pulling my A2D Skyshark around, which has similar weight and wing area to the Little Gem.  The North Pacific is half a gram lighter, which may be important given all the weight this model already has up front.  I made an extra noseblock and spinner, so I can build up both and see which works best.

The Tern prop was white, and the NP prop was red - neither of which would do for this model given that the original had a natural metal prop at the race.  For grins, I tried a product I'd read about for years in plastic modeling circles, Rub-n-Buff.  It is a wax-based silver finish that you rub in until dry, then polish to the desired luster.  Although a bit messy, it worked great!  We'll see how the finish holds up over time.

The s-hook prop shafts are a new product from Peck - nicely made, and perfect for folks like me that don't really care for music wire gymnastics.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on July 28, 2017, 03:37:40 AM
One of the English scale fellows used Rub n Buff on a simulated Alum cowl. It's certainly effective.

Reverse S hook Shafts from Peck - that's interesting.

Waiting patiently for your trim flights.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Pete Fardell on July 28, 2017, 05:47:40 AM
What a lovely model this is. "Little Gem" is right!


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 29, 2017, 05:58:02 PM
Thanks Pete - here's hoping it flies well.  Not much to show for the last few days - working on the canopy tonight.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 30, 2017, 02:31:17 PM
Fabbed and fitted the canopy and pilot. 

I wanted the canopy frame to match the tissue best as I could, so I chalked a piece of tissue, glued that to layout paper with spray adhesive and doped that.  Cut out the inner area where the glass goes, then glued the frame onto clear giftwrap plastic using Micro Krystal Clear (my favorite canopy glue).  Once dry I cut the frame and glass to shape, rolled it on a pencil to get the curves, then trial-fitted it to the fuselage.

I made a profile pilot, copying the image of Bob Downey from the picture Mark B. posted here of Little Gem at Reno in 1964.  I made it double-sided by mirroring the picture in PowerPoint and glued it in.

The real canopy is a single piece over the top, and sits a bit proud of the fuselage at the top rear.  I couldn't form that part of the frame with the rest of the canopy as a single piece, so I did it separately.  After the canopy was glued on, I trimmed off the top paper frame.  I cut a canopy top from the doped tissue sandwich, then burnished it over a firm rubber pad to coax as much complex curve as I could get into it.  Glued that on and burnished the edges to make it as smooth as possible.  Not perfect, but it looks pretty good.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on July 30, 2017, 04:25:20 PM
Finally got to the point of assembly!  The fin, stab and wings all went on fairly easily.  I used the magnet board to block up the fuselage square, measured the height of the wing at the root, then glued the wings on and blocked the tips up to match the plan's 3/4" dihedral per panel.  Seems like it's been a long haul to get to this point...

I really like the magnet board for this kind of work - makes it much easier to block everything in place and double-check measurements and alignment.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 06, 2017, 12:13:33 AM
Home stretch.  Built up a tailwheel and fitted it - the model has the rudder stretched a bit, so the tailwheel mounts a little aft of scale in order to line up with the back end of the rudder.

I put off working on the model for about a week thinking about how to mount the spinner.  Decided to fit a backplate to help line the spinner up and hold it in place.  Cut the backplate from scrap .015 styrene using a circle cutter, trimmed a flat on the back of the prop hub, then glued the backplate to the prop.  Next was a long session of fit-trim-fit again to cut slots in the spinner for the prop blades.  Once I was mostly happy with the fit I bent and trimmed the prop shaft, then glued on the spinner and fiddled with it to make it run as close to true as I could get.  It looks pretty good - still need to match some paint to the white tissue color and paint the spinner to get rid of the plastic look.

With the prop and tailwheel fitted and the motor peg installed the cg is about 1/4" forward of where it should be.  The hook is about 3" forward of the cg and the peg is about 5" back, so it should come in pretty close.  I haven't glued the cheeks on yet, so I can fit a motor, check balance and if necessary hollow the cheeks out a bit more to lighten the front end.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 06, 2017, 06:10:14 PM
Complete!  Ground another tenth of a gram out of the cheeks, drilled holes for the exhausts and glued the cheeks to the model.  Final step was to insert sections of black heat-shrink tubing in the cheeks to represent the exhausts.  20.75 grams without rubber, for an empty wing loading of .40g/sq in.  May still need a bit of tail weight, we'll see once the rubber is in.  Not much calm weather forecast for the next few days, so not sure when I'll get to start trimming.

This one was a bit of a chore at times, but it looks pretty neat all put together.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Pete Fardell on August 06, 2017, 06:23:00 PM
Really nice job! I love these little Goodyears but don't think I've ever seen this one modelled till now. You've really done it justice. Bet it will fly a treat too.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 06, 2017, 06:53:17 PM
Thanks Pete!  This airplane is a great subject as it was raced from 1949 into the 1970s, with multiple rebuilds/configurations and a number of great color schemes.  Tony Proux did a peanut plan for the early 1950s configuration, and Walt Mooney's plan is a great starting point for the configurations from 1957 on.  The Society of Air Racing Historians Facebook page that Mark Braunlich pointed me to earlier in this thread has a bunch of great pictures of the aircraft across the years (see the 1954 pic below).  I'm tempted to do another from the Proux plan in that blue/grey color scheme after I've recovered from this build and finished the next few projects.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on August 10, 2017, 05:50:39 AM
The wheel spats amaze me a bit Mike. I guess it's because I'm a lousy carver and your spats almost look like they came out of a mould.

Really fine effort.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 10, 2017, 10:26:35 PM
Thanks John. After the Waco and this one I think my favorite thing about the Tigercat I'm building now is that it doesn't have landing gear...

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Mark Braunlich on August 10, 2017, 10:49:20 PM
Early versions drawing.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 10, 2017, 11:07:45 PM
Thanks Mark - great drawing!  I had a drawing that showed the side view of the 1953 bubble-canopy version, but this drawing is much better.

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Mark Braunlich on August 17, 2017, 10:30:15 PM
Mike,
This is a fairly well known photo of the 1949 midgets from the roof of a hangar in Cleveland.   Notice #14 in lower right corner, Little Gem in it's earliest racing configuration with it's first wing.  Can't find any more views of it in '49, have you seen any?


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 19, 2017, 08:28:28 PM
Mark,

That's the only one I've seen with the '40s wing. 

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 19, 2017, 09:15:48 PM
Finally got a free day with some calm skies to put this one in the air.  It has promise, but needs a little more sorting out. 

Started out with a dummy nose plug (no prop or motor) ballasted to put the cg right on the spar where the McCombs numbers said it should be (this is about 1/16" ahead of the plan cg).  A few glides got the stab shimmed for a decent flat glide. 

Today's flights used a 12" loop of 1/8" rubber (1.5x hook-peg).  Put in the motor and prop, checked balance and repeated the glides.  Made a few tosses with hand winds, didn't see anything dramatic, so I put the Gem on the stooge and started working up in winds, selected flights here:  https://youtu.be/qvXd7KMct2g (https://youtu.be/qvXd7KMct2g)

Pitch trim wasn't consistent through the flights - everything on the model looks straight, and the stab shims aren't moving around, but twice, after a couple decent flights, the model climbed normally, started downwind cruise, then gradually pitched over into a power dive, breaking off the left wheel pant on impact.  After the first incident I played a bit with upthrust - a little bit may be helpful (second dive was after I took all the upthrust back out), but not much, as even a tiny shim had a big effect (see the 4th and 5th flights in the video).

The model also is spiral diving right when the power runs out - will add some left wingtip weight to see if I can tame that, and a maybe little left rudder if also needed.

I double-checked the balance this evening after repairing the wheel pants and it's still right at the spar.

Not a perfect first outing, but I think this will fly like a gem (ha!) once sorted - hope to get another calm day soon to work on it a little more.  Any observations or suggestions would be most welcome.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: USch on August 20, 2017, 04:24:26 AM
I dont like to sentence on youtube films because it is to easy to loose the proportions and see things which never happened. And also because I like to fly against torque and not with it, right that is.

But maybe one impression looking at the film, what about tightening the flight path climbing in a somewhat smaller circle. From the headline I see the model is intended to fly in a competition and with such a wide flight path it will immediately getting out of sight on a light wind day. And a tighter flight circle will help a lot to stabilise the airplane.

My 1-pence worth.

Urs


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: ZK-AUD on August 20, 2017, 06:22:49 AM
Mike I looked at the flights before reading your comments.  Saw the right spiral as the torque came off.  in fact you can see it wanting to straighten even while turning left.  whatever you have on to counteract the torque is causing the issue.  I think my first line of enquiry would be some right thrust and take off the right rudder or warp.
Regards Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: BG on August 20, 2017, 10:31:08 AM
Ok, so first thing to do I think is to check that you have adequate tail volume and the correct cg. You can use of one the various TVO/cg calculators to do this. When you have confirmed that your stab is large enough (TVo in the 0.65 to 0.75)  take the prop off, remove rubber, balance using a bit of clay and work on the glide. You probably know what you are looking for: a floating glide to the left.

When you have the glide sorted you can start working on the power pattern. I fly scale models left like the Czechs (it is generally more stable in my experience) so I use differential warps, less washout on the inboard (left) wing and more on the outboard wing. I typically run the thrust line through the vertical CG, which on a model like this means little or no down thrust. The wing should be ~2 degrees positive relative to the thrust line. I would use a bit of right thrust to counter torque at max turns and prevent the left spiral. I use a small gurney flap on the rudder to initiate the right turn in glide.

This is how I would approach it. You start with the calculation because you can't assume that the person who drew the plan actually ran the numbers... a lot of trimming issues for rubber models are caused by undersized stabs and incorrect CG locations. When you know the Two and CG are good you start with the glide to ensure that the model is in a good aerodynamic trim so that you do not end up solving flight surface problems with thrust line adjustments.

This is how we trim F1B and F1G, old timers, and scale rubber models.

hope this helps.
BG


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 20, 2017, 02:03:36 PM
Urs, Mike, BG - thanks for the inputs.  I got in some more flying this morning - a combination of less Gurney flap on the right wing, a good-sized Gurney flap on the left side of the rudder, a little more stab nose-up trim and some right and just a little up-thrust has generated some improvement.  With the rudder adjustment the left turn is tighter and the spiral at the end of the motor run is gone.  With the right thrust the initial climb is OK up to about 800 turns, above that it still torque rolls left into the ground, albeit more gently.  Model climbs well but still hangs on the prop a bit under power.

The torque roll above 800 turns tells me I should try a smaller cross-section motor - will try a 12" loop of 3/32.  If the torque roll persists I'll add a little more right thrust.

Transition to glide is still finicky.  Had a few flights with a decent glide, a few others where the model stalled at the end of the motor run, pitched down and didn't recover.  Glide from hand launch is really nice with and without prop, will recover from a fast launch with just a slight stall.  Transition on the problem powered flights looked like the model stalled and the stab never took effect - maybe blanked by stalled airflow over the wing or cheeks?

BG,  tail volume on this model is way small - about .37.  The wing is so big (~50 sq in - see pic below) you'd have to make the stab about 10" span (at the same chord as the plans) to get tail volume up to .65, or add an inch on either side and half an inch extra chord.  CG is spot on the McCombs calculated position (about 1/16" ahead of the plan position). I suspect the small tail volume has a lot to do with the erratic pitch performance.  The Gurney flap under the right wing should accomplish about the same effect as your differential washout.  Regarding your comments on down thrust, the noseblock had about 2 deg downthrust built in, the upthrust shims I've added are reducing that built-in downthrust.  Tell me more about your "Gurney flap on the rudder to initiate the right turn in the glide" - my (limited) experience has been that for low/mid-wing models I've had to add left rudder to tame the right spiral dive after power runs out.

Thanks again for all the observations and suggestions!

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: FreeFlightModeller on August 20, 2017, 02:15:21 PM
This has to be one of my favourite builds of the moment  :)
Enjoyed watching the video through FB earlier.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: FLYACE1946 on August 20, 2017, 02:21:42 PM
I know Mike will have it going even better very soon, He really is building and flying very nicely. Thanks Mike for the effort .


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Hepcat on August 20, 2017, 03:03:29 PM
Mike,
I must start by saying the Little Gem is and the flying looks promising too.
I must start by saying I am with Urs, I fly rubber models right under power and a correct sized power circle always seem to improve longitudinal stability as well but I will keep off that track.
She is obviously unsettled longitudinally which almost certainly will mean moving the cg forward. However I notice on most small scale models the tailplane have thin 'flat plate' tailplane sections which are liable to flow breakaway as soon as lift is demanded from them. I suggest trying a Gurney strip the full length of the TP trailing edge which ar least will give some semblance of a section. (just changing the incidence may cause breakaway even sooner.
Don't waste time putting weights on wing tips they have little effect compared to warps and tabs.
I don't understand the right spiral when the power runs out, is the freewheel working?
You are moving so fast with testing I had better stop here and wait for the latest report.
John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 20, 2017, 09:30:57 PM
Thanks guys.

John,  I've struggled getting low-wing models to fly right - forcing the right turn under power seems to exacerbate the spiral dive after power runs out.  I'm probably not doing it correctly...  I assume you're suggesting the Gurney flap on the upper side of the stab, to generate a nose-up moment with less negative stab incidence?

Here are the best two flights from this morning's session:  https://youtu.be/MU8AeirGj6s (https://youtu.be/MU8AeirGj6s). 

Both are a little stally under power, but the turn is better and the model climbs fairly well.  Note the glide at the end of the power run on the first flight, and the stall-dive-tuck under after power runs out on the second flight.  Although the CG is right where the tail volume says it should be, I'm thinking I need just a little bit of nose weight.

Thoughts?

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: flydean1 on August 20, 2017, 10:45:17 PM
Stall tuck under is usually a symptom of inadequate decalage and too aft a CG.  You've run the numbers and McCombs is a good authority.  Might be some of the stab is blanked out.  The Gurney flap on the stab might restore some effectiveness.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Crabby on August 21, 2017, 12:48:21 PM
Mike, that plane is really mid-winged and not low wing... in trimming it does make a difference. I wish I could expand on it some... the best I can do is let the cat out! It may have been flydean who enlightened me when I was trimming my diels Wildcat... one observation...It looks like your troubles begin at the transition where the knots are moving beyond the cg. Might be a thought to move the peg noseward a bay or so.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: BG on August 21, 2017, 02:24:13 PM
I like Crabby's suggestion. I tend to move the rear peg forward rather than add nose weight. Also serves to improve the tail moment situation.
bg


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 21, 2017, 10:25:34 PM
Crabby or FlyDean1, I'd be most interested to hear your techniques for trimming mid-wing models.  My experience is limited to low-wing warbirds and a couple high wing peanuts (which flew or not based on their own merits as built, not any trimming I attempted).  Had some discussion on the FaceBook Flying Aces page that suggests increasing the stab size.  I'm tempted to try moving the cg forward a bit to get more stability before starting to append area on the stab - if it doesn't work I can always move the cg back to the McCombs position.  Moving the peg forward isn't an easy option either, there would be some surgery and re-covering required.  Probably won't get to try anything before the weekend.

Cheers,

Mike.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: flydean1 on August 21, 2017, 10:43:16 PM
Re:  Crabby's comments.  Many years ago, we had sort of a one design FAC event featuring the Grumman Wildcat on the anniversary year (50th I think) of its' first flight.  We had about a half dozen entrants at KOI that year.  I had a slightly enlarged Stahl design.  There were at least a couple Diels kits, and at least one from Mike Midkiff's plans.  We discovered that in trimming, all of us assumed it should go to the "safe" direction to the left with torque.  All of us had trim problems until, mostly in desperation, we started turned them to the right.  Presto!!! they all started to fly.  All of us circled to the right, despite the origin of the design.  The F4F was a mid-wing airplane with the thrust line on the wing leading edge, and the stab slightly elevated above the wing.  If you enlarge the stab, go with a bit of span first.  More effective than chord.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: dslusarc on August 21, 2017, 11:37:23 PM
I bought one of these kits from Shortys as well, any chance on sharing the artwork file for printing the tissue? I like the black and white color scheme!

Don


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 22, 2017, 11:01:47 AM
Don,

Happy to share the graphics.  I'll need to clean up the working file - it's a 23 MB Powerpoint with lots of extraneous work-in-progress stuff.  Do you have an 11x17 printer, or should I drop the graphics into a letter-size format?

Flydean1, thanks for the trimming info - I have the Diels Wildcat in the stash for a future build.  I'm going to try a few things on this one before changing to a right turn, but I've got that in my pocket now in case things don't work out.

After thinking through all the comments, looking at the model and watching the videos some more I think I'm going to do the following for my next trimming session (intent is to increase stability to discourage the tuck and counter the torque to handle a bit more power)

1. Add a thin Gurney flap to the upper TE of the stab

2. Move the cg forward about 1/16" (put it just ahead of the spar)

3. Trim glide as required by adjusting the stab

4. Work up in power again, adding right thrust as necessary to allow more turns/torque without plowing in to the left at launch.

This week is busy, and the weekend may bring rain (which we need) - not sure how soon I'll get to try this approach.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Crabby on August 22, 2017, 11:29:28 AM
How are you going about moving the cg up?


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 22, 2017, 04:40:22 PM
Add a little weight to the nose.  I need to tighten up the noseblock a bit, so I'll do that first then ballast as required to get the balance where I need it.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: dslusarc on August 22, 2017, 05:59:55 PM
Don,

Happy to share the graphics.  I'll need to clean up the working file - it's a 23 MB Powerpoint with lots of extraneous work-in-progress stuff.  Do you have an 11x17 printer, or should I drop the graphics into a letter-size format?
Mike

Yes I have a large format printer. I bought it for printing tissue :-)   A 23MB file is fine for my email server and I have Powerpoint as well.  I sent you an email. Thanks for sharing the file!

Don


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Hepcat on August 22, 2017, 09:00:41 PM
Response to #106

Mike,
You obviously have your trimming problems well in hand although I am afraid some scale models will always be difficult.  There was just one further thing that I think should be said. Don’t always think that the equations of Bill McCombs and Jim O’Reilly are perfect. I think what they did was very sensible. They made a graph with CG position on the X axis and Tail Volume Coefficient on the Y axis. They then found the TVC and the CG of a lot of successful models and marked them on the graph. They then drew a straight line as near as they could passing through the middle of this group of dots.  The slope of this line expressed as an equation is what decides the CG position by their method. 
I have already said that is sensible and often helpful but there are a couple of things that should be kept in mind.  Calculation of the TVC requires the Moment Arm of the tailplane which is the distance from the lift line of the tailplane to the CG of the aeroplane (and is probably the most important factor in the TVC). However McCombs and O’Reilly don't know the CG position because that is what they are trying to so they decide to call the distance between the quarter chords of the wing and tail as the moment arm, obviously wrong and could be miles out.  The 2011 Sympo had a graph by Jim O’R of his method dated 1982 and had ‘dots’ for ten or more models by top flyers of around that time (35 years ago) and as far as I could see were all large competition rubber models. I think scale models need their own equations with some new constants.
John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: tom arnold on August 22, 2017, 10:33:16 PM
Good point, John. I have used the McCombs formula very successfully but there have been a couple of models that would not cooperate and acted too tail heavy in spite of my very careful calculations and drawings on the plans. I solved the problem by moving the CG a bit forward but I bet that Moment Arm difference is what caused it. Thanks for the explanation and suggestion and I hope somebody smarter than me will come up with that scale graphing and adjustment.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 22, 2017, 10:45:41 PM
John, true words.  For this model I keep looking at the cheeks and thinking that's a lot of planform area well ahead of the CG that's not included in the McCombs calculation.  That sure seems like it would reduce stability. 

While the stab may be small, it's a lot easier to move the CG forward than to increase stab area, and if it doesn't work probably the worst I have to face is repairing the wheel pants (again).

I do think this model has a lot of potential - it feels like it wants to fly, right up to the point of the occasional suicidal dive...

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: BG on August 23, 2017, 11:32:32 AM
Thanks for that explanation john. I did wonder at the choice of 25% wing chord to 25% stab chord for the moment arm. Perhaps we should start a new thread for this topic?

On the Little Gem: Perhaps some trial and error with some stab tabs would be good? I solved a tail volume problem with a cat glider by adding masking tape tabs to the stab until she started to behave. It worked like a charm and I was able to add and take away easily. If you do this you might be able to identify just how much extra area you need for a more reliable flight pattern. You could use light balsa tabs too so that you don't mess with the cg too much.

Speaking of CG did you move the rear peg forward?

B


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 23, 2017, 02:03:50 PM
BG,

I didn't move the peg forward.  It sits about halfway between the wing TE and the LE of the stab - next bay forward would have put it right at the TE of the wing.  As it sits the rubber runs about 3" in front of and about 5" behind the cg.  My trimming flights so far have been made with a single loop about 1.5x the hook-peg distance, and I'm using piece of 1/4" tube with the ends flared (see pic) as a bobbin on the motor peg (which is 3/32" OD tubing) to let the rubber move about and hopefully minimize bunching.

Stab expansion will be the next thing to try if cg adjustment doesn't tame the beast.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 23, 2017, 02:46:34 PM
Don,

Happy to share the graphics.  I'll need to clean up the working file - it's a 23 MB Powerpoint with lots of extraneous work-in-progress stuff.  Do you have an 11x17 printer, or should I drop the graphics into a letter-size format?
Mike

Yes I have a large format printer. I bought it for printing tissue :-)   A 23MB file is fine for my email server and I have Powerpoint as well.  I sent you an email. Thanks for sharing the file!

Don

Don - file sent.  Let me know if it didn't come through.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: ZK-AUD on August 23, 2017, 03:33:47 PM
Mike just looking at your rubber issue a couple of posts back.  Even on these littlies I go with a braided motor now.  if a loop of 1/8 would suffice I use 4 strands of 1/16 braided. If you have access to a stripper you can halve anything.   For my bobbins I've been using the plastic outer tube of R/C snake with a sliver of fuel tube stretched on either side of the rubber.  really light and I will make up 4 or 5 motors and number them so I can keep track of how many flights each has done and rest them.  with the braiding i find you can get a really long motor in and keep it all even


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: frash on August 23, 2017, 09:26:50 PM
Some indoor duration flyers use tubing at each motor hook on their stick models and it seems to work well.

Fred Rash


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on August 31, 2017, 05:18:49 PM
Got a bit more trimming in today - https://www.youtube.com/watch?v=h8Z1zje57kQ (https://www.youtube.com/watch?v=h8Z1zje57kQ).  Moved the cg forward about 3/32" for these flights, flying weight with the longer (14") motor was 24.1g.  I did not put a gurney flap on the stab as glide and flights didn't indicate it was needed.  Things were getting a bit breezy at the end, so I wrapped things up.  Longest flight was about 31 seconds, but I was looking more at flight dynamics than duration today.

Model is still really sensitive to thrust adjustments - don't think I really have the down and right thrust correct yet, but it flies better than the previous sessions.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on September 13, 2017, 10:32:57 PM
Took Little Gem out with a new motor today - 2 16" loops of 1/16" rubber.  I also trimmed off about half the left rudder flap.  Flights were a bit better, with three flights lasting between 35 and 40 seconds, and no instances of tuck-under.  With the reduced left rudder and longer motor I was able to put in a lot more turns without plowing in to the left at launch.  I added a little left wingtip weight, which improved the transition from power to glide, and added a bit more right and down thrust.

The model responded pretty well to the reduction in left rudder trim, but still seems to be fighting the left turn.  I think next time out I'll try trimming for a right turn under power, as Flydean suggested earlier.

One of the longer trim flights is included in this video:  https://www.youtube.com/watch?v=rvzBorDE5UE (https://www.youtube.com/watch?v=rvzBorDE5UE)

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Rudder flutter on October 03, 2017, 05:24:22 PM


Model is still really sensitive to thrust adjustments - don't think I really have the down and right thrust correct yet, but it flies better than the previous sessions.

Cheers,

Mike

Hey Mike. Lovely little model. I've been casually watching your trim progress with interest. I may be totally wrong here, but some of the flights look a little 'neutral' (lacking decalage), and you have talked about some pitch sensitivity. Have you done a quick incidence check by chocking up the fuselage on the bench until the tail is 'dead' level and then working out what positive incidence the wing has compared to tail? Just a thought, regards, Richard


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on October 04, 2017, 10:32:15 PM
Thanks Richard!  As set up right now there is about 2.5 degrees incidence differential between the wing root and the stab, somewhat less at the wingtips due to washout.  I moved the cg forward just a bit and that tamed the worst of the instability. 

Took the Gem out Monday and removed all the left rudder trim - result was a pretty decent open right turn under power (still a little stally), but a right spiral dive when the power came off.  Added back a little left rudder trim and kept the right turn but got a bit better glide. I have to watch wind direction carefully when launching - if it turns downwind early in the flight it doesn't want to come back around.  Had a scary moment when it flew off the field, across a road between traffic, and bonked into a window on a nearby fire station.  Popped off the spinner, no other damage.

I need to go find a hill and get the glide fixed, then play with thrust adjustments to get a bit more authoritative turn under power.

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: Hepcat on October 05, 2017, 08:52:18 AM
Michael,
You underrate your trimming ability.  Remember you choose prototypes whose aerodynamics are intended for vastly different purposes than flying as a free flight model. Your patient approach produces results that many will envy.  I was just writing to mention one arodynamic factor which may have an effect although I have no brilliant suggestions to counteract any difficulty it may cause.  I am talking of those beautiful wheel spats which, if a spiral dive started, could contribute a fair amount of side area low down to worsen the dive.  My only thought would be to continue towards right/right trim with right sidethrust and a 1/16" gurney flap along most of the starboard training edge.
John
 


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on October 05, 2017, 11:56:06 PM
Thanks John.  Spinner is fixed and the weather looks good for tomorrow morning - more right-right trimming is on the agenda.  Might have to throw the Tempest in the air a few times too...

Cheers,

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on October 07, 2017, 01:59:27 AM
Quote
As set up right now there is about 2.5 degrees incidence differential between the wing root and the stab, somewhat less at the wingtips due to washout.

if the washout is progressive along the wing then your effective longitudinal dihedral may be borderline at around 1.5deg or so and would agree with what Richard is saying.

I think John's(Hepcat) idea of adding a wash in gurney on the starboard wing would help considerably increasing the stability and leading to a safe right turn pattern.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on November 08, 2017, 11:29:14 AM
I've finally got the Little Gem flying in a fairly repeatable manner - as has been suggested here, it really likes to fly right-right.  I put a small wedge for right turn on the rudder, and ended up with a fairly long wedge under the right wing to keep that side up in the turn. What really turned the corner was adding some 2" x 5/16" extensions on the aft end of each side of the stab - this seems to have pretty much cured the pitch stability issues.

I took the Gem to WESTFAC and entered it in FAC Peanut Scale.  I didn't get around to flying it until the last day of the contest, didn't really have a good feel for the motor I had in the model and didn't have a blast tube that would fit through the nose, so the best time I got was 40 seconds.  It sure looked nice doing lazy floating right circles downwind, and I think with some power optimization it will be a competitive model.

The stab picked up a bit of a warp due to the temperature and humidity changes going from Texas to Arizona and back again.  I flew the model yesterday as-is, but I think I'll make a new stab with increased span/area so I can get rid of the extensions and not have to worry about the warp coming back.

Video of yesterday's flights:  https://www.youtube.com/watch?v=SUIGMi6-FkY&feature=youtu.be (https://www.youtube.com/watch?v=SUIGMi6-FkY&feature=youtu.be)

Mike


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: FreeFlightModeller on November 08, 2017, 12:45:08 PM
The climbing right turn suits the model .... nice flights  :)



Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on November 08, 2017, 05:01:42 PM
That rudder wedge is powerful Mike. It certainly looks like you are on the right path now.

John


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: MKelly on November 25, 2017, 04:13:32 PM
Had some good weather today and got in some flying.  Pulled out the Little Gem, put about 1300 turns into the tired two-loop 16"x1/16" motor and got a nice 1:05 flight.

https://www.youtube.com/watch?v=ln60FcCZ2Yk&feature=youtu.be (https://www.youtube.com/watch?v=ln60FcCZ2Yk&feature=youtu.be)




Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: FLYACE1946 on November 25, 2017, 10:10:54 PM
Mike I was happy you filmed the Big Cat so I know which way I need to shim the nose in order to open up the turn. I thought the video showed a real good flight.


Title: Re: Miller "Little Gem" build for FAC Goodyear mass launch
Post by: OZPAF on November 26, 2017, 07:13:55 PM
That's a magic flying model now Mike. The WACO SRE is amazing - even with a slight stall.

John