Logo
Builders' Plan Gallery  |  Hip Pocket Web Site  |  Contact Forum Admin (Account/Technical Issues)  |  Contact Global Moderator
September 17, 2021, 09:50:08 AM *
Welcome, Guest. Please login or register.
Did you miss your activation email?

Login with email, password and session length
 
Home Help Search Login Register
Pages: 1 [2] 3 4   Go Down
Print
Author Topic: Comet Sparky for P-30  (Read 4466 times)
0 Members and 1 Guest are viewing this topic.
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #25 on: April 14, 2011, 09:56:46 PM »

And here they are -- stab, rudder, and sub-rudder, sanded and ready to cover (give or take a coat or two of dope). This stab will be a good first try for me at wet covering with Esaki -- the bottom is flat enough to be easy, except for the rounding of the tips and leading edge; there's enough belly in the top surface to require pulling the tissue a little, but not so much as to require a master's touch. I'm surprised at how light these surfaces feel (outlines cut down from 3/32 to 1/16 and pretty light wood used for the rudder cross pieces, stab leading and trailing edge and stab spar); I'll have to try to get them on the pan of my reloading scale (or spend the time to make an alternate platform the same weight as the original pan), since I'm sure they're too light to get anything meaningful from the 5 g increments my diet scale gives.

Based on the video on YouTube I was referred to a couple weeks ago (Bern covering a good size P-51 fuselage with two pieces of Esaki -- compared to the 38 pieces the kit instructions called for), I understand I need to dope the frames enough to seal the tissue contact surfaces, wet the tissue with a fine mist spray and let the excess water drip off, glue stick the periphery of the frame and lay the wet tissue on, lifting as needed in order to pull out all the wrinkles, then rub the tissue down into the glue to fix it in place and let the tissue dry before trimming (Bern uses a hair drier or rather anemic heat gun). Bern doesn't try to stick down the edges until after trimming, and does that with glue stick, rewetting the edge with saliva.
Attached files Thumbnail(s):
Re: Comet Sparky for P-30
Logged

I'm here to have fun -- but winning isn't bad, either.
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #26 on: April 15, 2011, 10:37:30 PM »

Some more progress tonight. I reprinted the plan because I didn't like the way a couple of the tiles fit together in the wing and fuselage. This time I didn't join the top strip (with the wing plan on it) to the lower two strips (which have the side and top fuselage plans), for ease of handling, and I got them together with better registration (which will equate to better build accuracy, he said optimistically). I still had time to get the wing outline laid down. I almost committed a fairly annoying error -- gluing the leading edge pieces together at the dihedral joint isn't desirable until the two halves are completed and propped at the correct angle; it's then combined with adding the center rib. It's not supposed to be done before the spars or ribs are even in place. Fortunately, I caught myself before the glue was dry and was able to chop through the joint with a razor blade, ensuring that, even if it rebonds, the bond will be weak and easily separated when it's time to set the dihedral.

BTW, I found an error in the L10 version of the plan (checking the plan I'm using against the later 3408 version confirms it, as it's corrected in the later version); the rear spar is called out the same size as the main spar; that is, 1/16" x 1/4". Only problem is, the ribs aren't 1/4" deep that far back, and the notches that show on the wood print look just right for 1/16" x 1/8" -- which is what I'll use for the rear spar. No trouble, as long as the error is caught before the spar notches are recut to try to accommodate the too-deep spar.  Cheesy

I should have time (another couple hours, plus a break or two for glue drying) to finish the wing tomorrow or, at worst, Sunday, and hopefully will be able to cover the tail feathers and wing by Sunday night -- then it'll be time to embark on the fuselage, which looks likely to take more time than the wing and tail combined.

I think I've come up with a light, effective drag brake DT that won't require modifying the Sparky's original structure in any way -- more on that later.
Attached files Thumbnail(s):
Re: Comet Sparky for P-30
Re: Comet Sparky for P-30
Logged

I'm here to have fun -- but winning isn't bad, either.
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #27 on: April 16, 2011, 11:47:54 PM »

I finished the wing frame today; after the glue dries overnight I'll be ready to set in the dihedral, add the center rib, and, after another glue drying pause, carve/sand the leading and trailing edges, tips, and rib tops. Let's see, 94% of 7" under one tip is 6.58", or about 6 9/16".

Meanwhile, I doped the frames of the stab, rudder, and sub-rudder, and gave my first attempt at wet covering with tissue on the sub rudder. Aside from dropping the frame on the (rather dirty) rug under the table after applying the glue stick (resulting in some inevitable lint fibers under the tissue), it came out very well. Then again, I could cover a flat frame like the sub rudder dry and get a smooth finish (though I'm not sure I could water shrink it without pulling some cross pieces out of shape). The test will be tomorrow; after practicing some more on the rudder, I'll be covering the stab -- if I can do the top of the stab (tapered in both directions from center) with one piece, and later manage the same for the wing, I'll be ready to try covering the fuselage with one piece on each side.
Attached files Thumbnail(s):
Re: Comet Sparky for P-30
Re: Comet Sparky for P-30
Logged

I'm here to have fun -- but winning isn't bad, either.
Oldtime Flyer
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 335


"Keep it Simple"



Ignore
« Reply #28 on: April 17, 2011, 02:01:03 AM »

Ed's Ligards "Sparky" The Class "C" Contest Version he built and flew, Plan 10L-A

http://i257.photobucket.com/albums/hh215/Fadedepi/sparkyb-1.jpg

Otf'er
Logged
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #29 on: April 17, 2011, 02:00:44 PM »

I did a little Googling, and couldn't find a definition of Class C as it applied in the 1930s. Was this a span, weight-rule, cross-section rule, or what? And I note that the image you added has no sub-rudder -- apparently this is a feature that came and went.
Logged

I'm here to have fun -- but winning isn't bad, either.
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #30 on: April 17, 2011, 04:54:54 PM »

Why didn't I try covering with wet tissue about forty years ago? I might never have gotten so frustrated with stick and tissue as to put it aside for a couple decades, a couple different times. Even after learning wet covering with Silkspan, I never tried it with Esaki, because I'd read it was tricky. Nothing could be further from the truth. I've covered the tail surfaces of the 94% Sparky now, all done wet; the only mild difficulty was in handling large pieces of tissue and keeping the paper from sticking back to itself (even that wasn't particularly difficult to correct, though it's trickier the larger the piece of tissue, just because there's more to flop around).

Obviously, the flat surfaces of the rudder, sub-rudder, and bottom of the stab were no big deal (though even those came out much better than I'm used to getting, covering dry), but (in two tries, because I trimmed too close on the leading edge the first time, and the tissue pulled off) I was able to cover the top of the stab in one piece without a visible wrinkle anywhere (in the first photo, what looks like a wrinkle is the grain of the wood, exaggerated by leftover toner that wouldn't sand off because it was down in the grain).

For structures that can take the tension, I'll never cover dry again.
Attached files Thumbnail(s):
Re: Comet Sparky for P-30
Re: Comet Sparky for P-30
Re: Comet Sparky for P-30
Logged

I'm here to have fun -- but winning isn't bad, either.
Marco
Gold Member
*****

Kudos: 18
Offline Offline

Italy Italy

Posts: 521



Ignore
« Reply #31 on: April 17, 2011, 05:09:05 PM »

Zeiss Ikon, you are right, covering wet is a breathe of fresh air ! I tried it on my last scale model, a Re 2002, because I could not really face the idea of cutting and sizing strips after strips after strips of thin paper. It has been fantastic ! Two pieces, no wrinkles et voila' ! And the shape of the fuselage is not easy. Furthermore,as far as scale models, there is the advantage that the camo and all the other graphics can be printed straight on the tissue (with a laser printer or inkjets with water resistant inks) so in a matter of minutes the covering AND the decoration are sorted out ! You can do this only if you cover a fuselage with just two pieces !

Marco
Logged
Oldtime Flyer
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 335


"Keep it Simple"



Ignore
« Reply #32 on: April 17, 2011, 09:11:42 PM »

Z.I.

I mistakenly posted a copy of the wrong plan!...... Here is the correct plan L-10A and a copy of the rules as they were in the good old days. (1941 AMA Rules)......Until S.A.M. Messed with them.

http://i257.photobucket.com/albums/hh215/Fadedepi/scan0014.jpg  http://i257.photobucket.com/albums/hh215/Fadedepi/scan0012.jpg

OTF'er
Comet Sparky for P-30
Comet Sparky for P-30
Logged
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #33 on: April 17, 2011, 09:57:44 PM »

Okay, so Class C rubber was 100-150 square inches, and required 3 ounces per 100 square inches -- hence, based on the plan call out that the Sparky needed to weight 3.36 ounces, they calculated 112 square inches. At 94%, my P-30 Sparky has about 99 square inches -- but I'm hoping to build well under three ounces (which would be 85 grams, near enough); I'm aiming for fifty grams, but I'll be happy if I finish under sixty.

I see the apparent difference in the L-10A plan compared to the one I'm building from is the competition airfoil (more cambered, concave under surface that should glide better but is harder to cover) and an option that I take to be a single-wheel gear, with fins near the tips of the stab replacing the center sub-rudder. The latter is moot for P-30, where landing gear and ROG capability aren't required. I'll be building gear for my Sparky, but I'll probably make it a plug-in setup similar to what I put on my Fat Lancer (and unlike the Lancer, I'll trim without the gear and expect to fly without it for other than sport flights).

I do have a rules question -- AMA rules for P-30 specify that the plastic propeller can't be modified other than flash removal and balancing by adding mass, but I don't see anything that says I can't put a spinner over the hub of the unmodified propeller. My Sparky would look better, and probably also fly better, with a spinner similar to the original -- is that verboten? If it's okay, I can make a spinner with a plate that goes behind the propeller and a cone that fastens from the front, using tiny magnets (if I can get them in time) or possibly little patches of hook-n-loop material -- and won't interfere with the operation of the propeller's molded-in freewheel.
Logged

I'm here to have fun -- but winning isn't bad, either.
Tmat
Titanium Member
*******

Kudos: 69
Offline Offline

Canada Canada

Posts: 2,981




Ignore
« Reply #34 on: April 17, 2011, 09:59:45 PM »

Spinners are o.k for P-30 as far as I know.
The Gizmo Geezer P-30 front end comes with an optional spinner.

Tony
Logged

F1B guy...
But don't hold that against me!
RonT
Silver Member
****

Kudos: 2
Offline Offline

United States United States

Posts: 200


Support our cottage industry mfrs. & suppliers




Ignore
« Reply #35 on: April 17, 2011, 10:04:02 PM »

Gizmo Geezer front end and prop with "spinner" are P-30 legal. Wink

Ron
Logged

Ron T
AMA, NFFS
McCook Field - FAC
Cloudbusters
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #36 on: April 18, 2011, 07:08:09 AM »

Spinners are o.k for P-30 as far as I know.
The Gizmo Geezer P-30 front end comes with an optional spinner.
Gizmo Geezer front end and prop with "spinner" are P-30 legal. Wink

Good to hear about the spinner. I've wondered for a while about the Gizmo Geezer -- seems to me the product information claims a 1.25:1 gear ratio, and AMA rules specifically prohibit gear drives other than 1:1 for all rubber power models. Did I miss an exception for P-30, or am I misinterpreting the restriction?
Logged

I'm here to have fun -- but winning isn't bad, either.
Pit
Palladium Member
********

Kudos: 132
Offline Offline

Germany Germany

Posts: 5,577


aka staubkorb


WWW

Ignore
« Reply #37 on: April 18, 2011, 07:31:48 AM »

There is NO gearing on the Gizmo prop assemblies.

http://www.gizmogeezer.com/pfw.htm
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
RonT
Silver Member
****

Kudos: 2
Offline Offline

United States United States

Posts: 200


Support our cottage industry mfrs. & suppliers




Ignore
« Reply #38 on: April 18, 2011, 07:47:32 AM »

Quote
seems to me the product information claims a 1.25:1 gear ratio

Gizmo supplied props have a typical P/D of 1.25.

Quote
There is NO gearing on the Gizmo prop assemblies.

Exactly right! Try it - you'll like it! Grin
Have a GREAT Day everybody!

Ron
Logged

Ron T
AMA, NFFS
McCook Field - FAC
Cloudbusters
Tmat
Titanium Member
*******

Kudos: 69
Offline Offline

Canada Canada

Posts: 2,981




Ignore
« Reply #39 on: April 18, 2011, 08:06:23 AM »

Pitch to Diameter ratio of 1.25:1, not gear ratio!

Tony
-I'm also not sure about the gearing rule either. I've seen P-30 models with gears lately (as far as I know they are legal) and scale models with gears.
Logged

F1B guy...
But don't hold that against me!
Pit
Palladium Member
********

Kudos: 132
Offline Offline

Germany Germany

Posts: 5,577


aka staubkorb


WWW

Ignore
« Reply #40 on: April 18, 2011, 08:10:26 AM »

I think they're ALL running 1:1.
Logged

A Dedicated Convert to:
WWWoFF (Wonderfull Wacky World of Free Flight)

Comparing Spammers to a pile of organic waste is an insult to the organic waste!
Tmat
Titanium Member
*******

Kudos: 69
Offline Offline

Canada Canada

Posts: 2,981




Ignore
« Reply #41 on: April 18, 2011, 09:06:59 AM »

See this thread here: http://www.hippocketaeronautics.com/hpa_forum/index.php?topic=4333.0

Dave Sechcrist describes his 5:1 geared P-30 hub. Others have made 4:1 geared hubs for P-30. I must assume that it is AMA legal or else why did they take the trouble to build it?

I had a quick boo of the AMA rules for outdoor rubber here: http://www.modelaircraft.org/files/2011-2012OutdoorFreeFlight.pdf
I see nothing at all about gearing in the general rules, nor in the specific rules for P-30.
Whether gearing is desirable or not is another story, but it doesn't seem to be illegal for AMA competition.
Anyone?

Tmat
Logged

F1B guy...
But don't hold that against me!
applehoney
Titanium Member
*******

Kudos: 280
Offline Offline

Canada Canada

Posts: 3,195




Ignore
« Reply #42 on: April 18, 2011, 01:24:32 PM »

Gears (and movable surfaces, other than d/t) are excluded from P30 flown at the Great Grape Gathering, Geneseo
Logged
RonT
Silver Member
****

Kudos: 2
Offline Offline

United States United States

Posts: 200


Support our cottage industry mfrs. & suppliers




Ignore
« Reply #43 on: April 18, 2011, 01:44:44 PM »

Gears (and movable surfaces, other than d/t) are excluded from P30 flown at the Great Grape Gathering, Geneseo

I'm pretty sure the AMA rules say the same.

Ron
Logged

Ron T
AMA, NFFS
McCook Field - FAC
Cloudbusters
Tmat
Titanium Member
*******

Kudos: 69
Offline Offline

Canada Canada

Posts: 2,981




Ignore
« Reply #44 on: April 18, 2011, 02:45:07 PM »

The AMA rules do not preclude moving surfaces as far as I can see, nor gears. If you are flying P-30 to those rules Jim, then they aren't quite the AMA rules. They might be better rules...... but...

The official rules are below. No mention of lack of moving surfaces, nor of gears.
 
AMA P-30 rules:

P-30 MODEL
For event 124.
1. Models shall conform to the following specifications:
1.1. No part of the model shall exceed 30 inches when it is in assembled condition.
1.2. The minimum weight of the model without rubber motor shall be 40 grams.
1.3. The lubricated rubber motor shall not exceed 10 grams.
1.4. The propeller shall be a commercially available plastic freewheeling propeller between 23 and 25 centimeters (9.05 and 9.84 inches) in diameter. Only the following changes will be allowed:
1.4.1. Flashing may be removed.
1.4.2. Balancing by the addition of weight to one blade will be allowed.
1.4.3. Enlarging the hole of the propeller hub will be allowed in order to accept a larger diameter shaft and/or a bushing cut from metal tubing.
2. Launching shall be as specified for land plane models, Free Flight General.
3. A flight of more than 20 seconds shall be considered an official flight.
4. There shall be no limit to the number of attempts allowed in order to record three (3) official flights.
5. The maximum recorded duration for each flight shall be 120 seconds.
6. If a tie exists after three (3) flights have been recorded then each successive flight shall have a maximum duration of 30 seconds more than the previous flight.

Tony
Logged

F1B guy...
But don't hold that against me!
bertcarr
Silver Member
****

Kudos: 9
Offline Offline

South Africa South Africa

Posts: 110





Ignore
« Reply #45 on: April 18, 2011, 04:21:43 PM »

I have a very old Dremel scroll saw which I use to cut ribs etc. The blades that used to be available included a fine tooth one that is ideal for thin balsa.I bought this saw in the 70's and have used it over the years.

I realize that this does not help much but it may be a good idea to see if Dremel still makes this saw as it was sold for a very good price.

Last year I built a "Wren" a FROG design tow line glider and used the printed paper glued to the strip to mark the parts. I found that if the cutting can be done quickly the paper is easily taken off the balsa.
>You make me itch to build this type of model again. The build as far as you have got looks very good. I am waiting to see the DT.

Bert
Logged
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #46 on: April 18, 2011, 05:57:27 PM »

You make me itch to build this type of model again. The build as far as you have got looks very good. I am waiting to see the DT.

I'm just hoping I have time to finish this model before the Raeford fun fly on April 30 -- if not, I may not have any opportunity to attempt a full power flight before the contest on May 14-15. I am, however, discovering that making and using better tools often saves time (I've known about notch sanders for a very long time -- I think I recall reading about them in the 1970s -- but never bothered to build one until now), and techniques that produce a better result are often quicker than those that produce a mediocre end (like covering wet -- takes no more time to get the tissue on than covering dry, but the wait for attachment cure, spray, and shrink/dry are compressed into just waiting for the tissue to dry; saves most of an hour per surface while producing a greatly superior result). Barring unforeseen events, this seems likely to be my best build ever.

Tonight I'll be shaving/sanding the wing, then doping the frame, and may or may not have time to cover.

As for the DT, all I'll say until I reach the point of fabrication is that it's a drag-brake type and requires no modification of the canonical airframe as set forth on the L-10 plan -- and should weigh between one and two grams plus timer rigging, but produce enough drag to generate a very steep descent. I hope to get the fuselage built this week, then I can spend next week making the DT work...
Logged

I'm here to have fun -- but winning isn't bad, either.
applehoney
Titanium Member
*******

Kudos: 280
Offline Offline

Canada Canada

Posts: 3,195




Ignore
« Reply #47 on: April 18, 2011, 07:33:59 PM »

Quote
they aren't quite the AMA rules

It's not quite an AMA contest
Logged
Zeiss Ikon
Gold Member
*****

Kudos: 10
Offline Offline

United States United States

Posts: 567


Topic starter


Ignore
« Reply #48 on: April 18, 2011, 08:56:15 PM »

I've got the left wing covered, top and bottom, at this point (sorry, no photo yet), and I'm finding a little problem; the trailing edge (1/16" x 3/8" strip -- plan calls for 3/32" thick) was bending downward (like a deployed flap) pretty badly by the time I got the top covering in place. I've got the wing pinned down and drying now, and I'll plan to dope this half and pin in down again before I start the right wing (which means I probably won't get the other wing covered tonight). I had to actually pin through the trailing edge to get the wing to lie down flat, but even so, the wrinkles produced in the top covering when I took the "flap" out have already shrunk out. The question here is basically whether this wing structure can take the tension of wet covering -- I was rather surprised by how flexible the Sparky wing is. I'm sure it'll be stiffer with a taut skin -- if it doesn't warp into a potato chip shape, that is.

I think for the right wing I'll try wetting both tissue pieces, so I can apply the top with less delay after getting the bottom on. Just have to figure out how to hang both pieces for a few moments while I drop the spray bottle and pick up the bottom tissue. Four hands or so would sure be a help for this...
Logged

I'm here to have fun -- but winning isn't bad, either.
Dave Andreski
Titanium Member
*******

Kudos: 82
Offline Offline

United States United States

Posts: 3,052




Ignore
« Reply #49 on: April 18, 2011, 10:10:10 PM »

Z.I.

I mistakenly posted a copy of the wrong plan!...... Here is the correct plan L-10A and a copy of the rules as they were in the good old days. (1941 AMA Rules)......Until S.A.M. Messed with them.

http://i257.photobucket.com/albums/hh215/Fadedepi/scan0014.jpg http://i257.photobucket.com/albums/hh215/Fadedepi/scan0012.jpg
Hi Thom,
I recognized your mistake right away but knew you'd be back soon to correct it.

Dave Andreski
Key West, FL
Comet Sparky for P-30
Comet Sparky for P-30
Logged

Aspire to inspire before you expire.
Pages: 1 [2] 3 4   Go Up
Print
Jump to:  

Powered by MySQL Powered by PHP Powered by SMF 1.1.21 | SMF © 2015, Simple Machines Valid XHTML 1.0! Valid CSS!