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Outdoor Free Flight Forum => Catapult Launched Gliders => Topic started by: tross on May 29, 2019, 10:40:46 AM



Title: 8" F-16 CatJet Build
Post by: tross on May 29, 2019, 10:40:46 AM
I have some pictures of the 8" F-16 catjet I built this past Friday.
Sunday (race day) was a good day to fly, so there's some video.
The wood selection is pretty much the same, light weight C grain for the wings.
Light weight flexible wood for the control surfaces and the canopy.

Some flights over 30 seconds.  :o
Crashing on the house, and into trees as usual. 8)
I wouldn't have it any other way. :D

A short and boring video of the cutter.
https://www.youtube.com/watch?v=qff5EWgHX7U

Flights.
Small plane, so full screen recommended...
https://www.youtube.com/watch?v=_U4QEa8BTiY

AUW 4.15 grams.
More pics coming.

Tony


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on May 29, 2019, 12:32:09 PM
Thanks Tony for showing these pictures. Are you launching the F-16 with a single loop of 1/8 rubber?


Title: Re: 8" F-16 CatJet Build
Post by: tross on May 29, 2019, 12:40:08 PM
You're welcome FLYACE1946.

Most of the initial trim flights are very slight pulls on 1/8".
A coordinated roll out into the wind and glide.
Less walking, more trimming this way.

I slowly add power and then start to angle up.
In the end, 2 loops of 1/8" about 9" long.

Tony


Title: Re: 8" F-16 CatJet Build
Post by: tom arnold on May 29, 2019, 01:28:40 PM
Tony, that little F-16 is a minor marvel for those of us who have tried cat jets. It has no dihedral and mid wing but retains that big vertical tail which you'd think would all work against it. Then your transitions are delightful, rolling out with no loss of altitude right at the end of the launch energy. How do you set up your trim on the control surfaces? do you use wingtip weights? Do you launch with wings level, 45 degrees, or 90 degrees to the ground? But most of all, how do you get that smooth transition? Many thanks in advance from a lot of frustrated jet jocks.


Title: Re: 8" F-16 CatJet Build
Post by: tross on May 29, 2019, 02:53:38 PM
Hi Tom,
I hope you are well and thank you. :)
The little 8" is my personal favorite.
It uses very little wood and flies well for sure.

I'll take some pictures of the model tonight so we can look at it.
Please keep your feedback coming.

For now I can say I'm not using any tip weight.
There is a very slight amount of dihedral.
It depends on the wind speed as to how I'm launching.
I'll keep that discussion open so we can discuss it further.

If I have or would consider a main objective it would be a very long coordinated roll out and turn.
I'm trimming for a roll, keeping the nose down.
Low launch and at full power.
I'm 100 feet from the house for the clip that is a more gentle transition.
I've hit the house during that phase of trimming.
So a very slight incidence on the tail is required.
Once I have that in say 3 mph head wind I can start to move up.
The breeze at the top helps the high launch transition stick.
I'm flying a weather vane.


Tony


Title: Re: 8" F-16 CatJet Build
Post by: Don McLellan on May 29, 2019, 04:56:16 PM
Hi Tony,

I like the video of the craft cutter.   ;D ;D ;D  How thick is the wood, and which blade are you using in your craft cutter?

Don


Title: Re: 8" F-16 CatJet Build
Post by: tross on May 29, 2019, 09:31:14 PM
Hello Don,
You're just being nice.
The blade I'm using here is the Silhouette premium.
The wood is shaved from balsa block to .06" and  finished using an orbital 220 grit w/vacuum set up to .05"
between 2 pieces of 16 gauge stainless sheet.
The cut is .04" deep, leaving the .01" to hold it all together.
I stole that from you, but it's been so long it's now my idea..... ;D :) :D ;D ::)

Close up pictures are attached below.
I don't think this is anything new, but might help someone with set up.

Pic 1 the stab is flat.

Pic 2 from the front you may notice the dihedral is very slight, but is there.
     Also a very small amount of washout port wing.

Pic 3 from the back, the stab is a little blurry but you may notice a little stab tilt.
     Also the very small amount of left rudder.

4,5 and 6 are this installments build pictures.

I started with the fuselage.
The grain direction is hopefully on display.
The camber and wing incidence are builder's choice really.
They can be revised to fit flying preference.
The lower camber jets I have built have flown well.

Tony


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on May 29, 2019, 09:41:59 PM
Tony the pictures sure do help. Again many thanks for taking the time to show us.


Title: Re: 8" F-16 CatJet Build
Post by: Don McLellan on May 29, 2019, 09:42:25 PM
Hi Tony,

No, no, everything I know about craft cutters came from you!   ;D

Beautiful work as per usual and a very interesting thread.

Don


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on May 30, 2019, 02:53:53 AM
What a nice little beast Tony :) I couldn't see your flight - I'm currently having hassles with UTube but if it flies like your previous efforts - it would be impressive.

John


Title: Re: 8" F-16 CatJet Build
Post by: tross on May 30, 2019, 10:28:55 AM
Ah, so it's been long enough then Don. ;D

It's probably the browser John. :P
You can load one of the suggestion vids to the side there, and hit the back button, then the refresh a couple of times.
I hope you get to see it eventually.

Did you notice anything in the trim set up pictures Tom.
I agree that the trim settings are important.

Tony


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on May 31, 2019, 01:28:03 PM
 Tony I finally took out the two F-16 jet cats today and I was very pleased with the results. The one you built flew like crazy. The one I built shows promise but the slight bow in the fuselage seems to affect the flight duration. These two F-16's sure do weather vane. I sure do like how they fly. Mike Kelly and I were being entertained by two F-16's flying around from Lackland AFB this morning. They made two circuits over us and weren't taking too much time for each pass. Texas Air National Guard fwiw.

Oh BTW we will be taking a trip to a contest tomorrow so there might be some future flights recorded for this website.

Sure is fun to JETCAT...THANKS TO FAC for the opportunity to fly a jet


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on May 31, 2019, 08:39:23 PM
Well finally got to see the little beast flying. That is a lot of fun and what a great flying model. How do you hold the balsa down on the moving platen on your craft cutter?

Thanks for the tips re watching the video - it just played without any drama today.

John


Title: Re: 8" F-16 CatJet Build
Post by: tross on June 01, 2019, 12:35:36 AM
Hi John,
I'm glad it's working now. :)
I'm using Dritz Basting Spray. Temporary adhesive for sewing and quilting.
I little mist on the carrier and the wood stays put.

How were the flying conditions today FLYACE1964.
Is the model durable enough to take some hits?
I have to say, there wasn't much time to final trim the one I sent.
It probably needs your finishing touch. 8)

I was caught off guard by Tom's questions about the launch angle.
To be honest, I wasn't aware there was an issue.

I hope the video below helps clarify what I'm doing anyway.

If it isn't rolling enough, it will lose altitude at the top.
If it's rolling too much it will stall, but usually recovers.
I'm launching away from the wind but not 180°. More like 135°.

The direction, launch angle, and pull tension are all slightly adjusted during an outing.
The angle away from my body is just where it falls.
I'm not sure at that high launch angle it has much effect.
Launching upward is really the only way I've found to see what it's doing up there.

I'll get some build pictures of the wing next time.

This video shews the launch angle, flights in calm conditions,
and a couple of slow motion shots of the long roll out trim I am looking for.

https://youtu.be/FqVm_4b8EJ0

Tony


Title: Re: 8" F-16 CatJet Build
Post by: Don McLellan on June 01, 2019, 02:11:13 AM
.....shews.......    ;D ;D ;D ;D


Title: Re: 8" F-16 CatJet Build
Post by: tross on June 02, 2019, 08:11:55 PM
Check your email Don.
You should have it. :)

For the wing, I'm holding the parts together and lightly sanding the edges.
The edge between the front and back section gets a slight angle for camber.

The left and right wing are assembled,
then the two halves are glued together to complete the assembly.
This is where the slight dihedral shows up.

Fast forward to today and the model now has some color.
Some panel lines and markings will help it look better I hope. :)

Tony


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on June 02, 2019, 08:36:05 PM
Thanks for that Tony! I'm a little surprised by your successful use of a downwind launch direction. I would have thought that would kill the climb but it obviously works well.

Happy flying.

John


Title: Re: 8" F-16 CatJet Build
Post by: tross on June 02, 2019, 09:15:14 PM
Hi John,
I suppose it does a little but it curls around quickly.
By the time it needs the help it's more toward then away.
A sort of long loop, roll, turn, ending up facing into the breeze without lifting the nose....thing. ;D :) :D ;D
Even though that's my hat cam on the ground, the wind is over the camera and to me.
Tony


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on June 03, 2019, 01:32:36 PM
Hi John, Well Tony the Leading edge of the wing hit something so I have a problem to fix. The weather Saturday was pretty nice but it sure was HOT. I got sunburned thru my shirt. I had hoped for some video to show you something but the Skyray handled things better since I got it out of the box and I took second place in the Flying Horde Event. No big deal since we had just 3 flyers.
I'm glad it's working now. :)
I'm using Dritz Basting Spray. Temporary adhesive for sewing and quilting.
I little mist on the carrier and the wood stays put.

How were the flying conditions today FLYACE1964.
Is the model durable enough to take some hits?
I have to say, there wasn't much time to final trim the one I sent.
It probably needs your finishing touch. 8)

I was caught off guard by Tom's questions about the launch angle.
To be honest, I wasn't aware there was an issue.

I hope the video below helps clarify what I'm doing anyway.

If it isn't rolling enough, it will lose altitude at the top.
If it's rolling too much it will stall, but usually recovers.
I'm launching away from the wind but not 180°. More like 135°.

The direction, launch angle, and pull tension are all slightly adjusted during an outing.
The angle away from my body is just where it falls.
I'm not sure at that high launch angle it has much effect.
Launching upward is really the only way I've found to see what it's doing up there.

I'll get some build pictures of the wing next time.

This video shews the launch angle, flights in calm conditions,
and a couple of slow motion shots of the long roll out trim I am looking for.

https://youtu.be/FqVm_4b8EJ0

Tony


Title: Re: 8" F-16 CatJet Build
Post by: tross on June 09, 2019, 09:18:08 PM
Once the wing and tail section glue has set, there is a dry fit-up.
Picture 1 below is part of the fit with no glue.
It's more convenient to sand the parts separately prior to final assembly.
Each section can be laid flat on the building surface and thinned, or given a more aerodynamic form.
As seen in picture 2, the tail section is reduced.

The wire reinforcement I am using is .03" aluminum GTAW filler metal.
Shaped to fit, then CA'd into place.
I hold this reinforced section during launch.

I hope you get some more favorable flying conditions FLYACE. :)

Tony


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on June 10, 2019, 12:34:20 PM
Tony where does the .03 wire come from? I really like the easy approach to using it. I shaped my wire with my round nose plairs and then used Duco cement to glue it in place. Still working to match your flights but weather has been too stormy to get back out.


Title: Re: 8" F-16 CatJet Build
Post by: tross on June 10, 2019, 10:13:52 PM

It's a welding filler metal.
I realized later I should have stuffed more if it in the box. :P
It's a breeze to work with and a good size round for the rubber IMO.

I do like Duco for sure.
Easy glue to like for a lot of reasons.

I'm using CA for that spot around the wire however.
If you hear some crackling sounds  :o you might consider it. ;D
A little solvent to break the Duco free and re glue as you already know etc. :)

In the first picture below the nose and all of the leading edges are sanded to a knife point.
The thick CA is ran along those edges and wiped/spread using a latex-free vinyl glove.

The wing is more easily final sanded to shape without the ends (picture 2).

In addition, those parts are sanded to shape while loose (picture 3).

Measuring and sanding the wings square with the fuselage (4), and then finally you might see the far wing tip glued in the last picture.

What was your impression of the cuts FLYACE.
Hopefully it wasn't too much trouble getting the parts loose from the sheet.

Tony


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on June 10, 2019, 10:42:41 PM
Tony your cuts were fine. I had a sharp xacto to ease the final cuts. The entire experience was amazing. My son teaches welding so maybe I can get some more of that wire from him. I really like using that material. Thank you for your information. I want to try launching left handed and down wind as you do. Sure is an amazing flyer you came up with.


Title: Re: 8" F-16 CatJet Build
Post by: tross on June 12, 2019, 09:50:54 PM
The only reason I have a left hand is in case something happens to my right hand. ;D :) :D ;D
I leave the simple task of letting go of the jet to it.
All the hand-eye-consistent-aiming, tension-sensing, wrist-flipping is assigned to the right hand.

With a new model it's all about trimming for a steady glide.
90% of the flights are set up to fly as you will see in the short one-flight clip below.
The cg is moved very slightly forward, along with a small increase in tail incidence.

I'm either using tungsten putty or sticky clay for ballast.

The putty is glued on with Duco, and then a thick CA to cap and smooth it.
Sticky clay is spread out in a similar way without the glue or CA.

https://youtu.be/htJRyaTTRB0

Tony


Title: Re: 8" F-16 CatJet Build
Post by: tross on June 17, 2019, 09:28:18 PM
The low powered flights help check the glide.
Pulling back fully on a 9" loop of 1/4" at a low angle can help check the launch.
When it travels the length of the yard without any issues I start moving up.
The short video below is the progression.
Not intended as a end all be all obviously.

1.Down low, low power with initial trim to make sure it will fly/glide.

2.Shoot it full power across the yard at a low angle.
       Trim out any high speed issues.

3.Move to a higher launch angle at full power and trim for rotation.
       
The windy conditions in this video required a bit more stability and recovery.
It can be flown closer to the edge in calm air.
I'm asking that the build be considered complete.
Here's the video, happy flying, and thanks again. :)

https://youtu.be/rhi7m0pbEX4

Tony


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on June 18, 2019, 04:44:23 AM
Well done thread Tony.

John


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on July 01, 2019, 11:07:52 PM
How high does the F-16 go on the high power, high angle launch ? I hope you know I try to copy the same way you fly.


Title: Re: 8" F-16 CatJet Build
Post by: tross on July 06, 2019, 10:00:55 AM
I'm not really sure to be honest.
I do know the heavier model I've been flying gets a little higher.
It's wearing me out. The glide angle improved with the higher speed and less flap set up
and it flies away in a hurry.
More walking. ::)
I suppose that's good for the heart but bad for the toes.
It's hung up in a tree right now. Maybe the wind will blow it down.

Tony


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on July 06, 2019, 08:21:34 PM
Bad for the toes? :) :)

John


Title: Re: 8" F-16 CatJet Build
Post by: tross on July 07, 2019, 07:10:09 PM
Toes. ;D :) :D ;D
I've been trying out a more circular glide trim. 8)
The turn=drag and duration takes a little hit but there's less walking and more flying. :D
There's a 35 second flight in here so it's not all bad... :o

https://youtu.be/uCjJ6noMnGk

T


Title: Re: 8" F-16 CatJet Build
Post by: MKelly on July 07, 2019, 10:08:26 PM
Great flights Tony!  I had everything cut out Monday morning, then I crashed the Waco and spent the week rebuilding it.  Look forward to getting this one in the air.

Mike


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on July 07, 2019, 10:31:22 PM
This flying is looking really swell. Anything that saves a few steps is really fine unless the circle is way too small and that hurts the duration. I think this F-16 has the h stab tips down as the plan shows.

Looks better all the time.


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on July 08, 2019, 05:21:59 AM
Well that will really help the toes :D You have that well sorted Tony - very consistent transitions as well. It's a winner.

John


Title: Re: 8" F-16 CatJet Build
Post by: tross on July 09, 2019, 09:49:18 AM
I wouldn't go that far John but I appreciate it. :)
The jet is fun to fly but I don't know that it's ever really sorted.

That is the scale stab set up FLYACE1946 good eye.
I think what you're doing with the tissue skin will have a much better look than this paint I've been hacking away at.

After watching some of those MKelly videos I know it's in good hands.
I had to put my YT like button in a bucket of water to cool off. ;D :) :D ;D

Tony


Title: Re: 8" F-16 CatJet Build
Post by: MKelly on August 12, 2019, 04:59:39 PM
Tony,

I finally finished up all my repairs from Geneseo and got started on the F-16.  The wood is beautiful, subassemblies went together well.  Spent an hour or two sanding and taped the subassemblies together to see how they fit - everything is clean and tight!  The woodwork is now out in the garage letting the sanding sealer dry while I'm in here working up some graphics.

Allen got some launches in with his Thunderbird F-16 on Saturday - it was very windy but by the end of the session he was getting some nice flights.  Look forward to getting this one in the air.

Mike


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on August 12, 2019, 08:07:30 PM
You've put some work into that design Tony - Mike's bare wood shots show the grain selections very well.
It looks great Mike. I didn't realise that you were a Duco user!.

Happy flying
John


Title: Re: 8" F-16 CatJet Build
Post by: tross on August 12, 2019, 09:55:35 PM
It's certainly humbling to watch your work Mike.
Your builds are very clean.
I'm glad it didn't give you to much trouble.

FLYACE1946 mentioned he was getting some time in.
Thanks for the updates. It's fun to follow along. :)

Tony


Title: Re: 8" F-16 CatJet Build
Post by: MKelly on August 13, 2019, 11:54:50 PM
Thanks John and Tony, it's coming together nicely.  John, I still use Titebond II for built-up structure assembly, but I've really come to like Duco for assembling doped components and sheet parts.

Got the beast covered today.  Printed one of the Belgian Tiger Meet schemes on some old bug-eaten yellow Esaki, used colored pencils to whiten up the Tiger's face on the tail and blacken out some of the artifacts from scaling the graphic to match the airframe.  I tried something different for attaching the tissue.  I sprayed the back of the tissue with Krylon Easy-Tack repositionable adhesive, then smoothed the tissue over the sealed and sanded fuselage.  This worked really well - it was easy to get the tissue lined up, and much more forgiving than glue stick.  Once the tissue was lined up, smoothed down and trimmed I sealed the edges with UHU glue stick.

With the fuselage covered I glued in the horizontal structure, let that dry, then sanded all the joints smooth and applied the rest of the tissue.  Weight at this point is about 7.2g, with final coat of dope and balance weight still to add.

Sure builds into a pretty airplane, hope the tiger motif doesn't make it disappear in the dry Texas grass...

Mike


Title: Re: 8" F-16 CatJet Build
Post by: tross on August 14, 2019, 05:29:28 PM
Well it does when you build it for sure! :o :o :o

I only flew one close to that weight (7.9) and it was a hoot.
The plane in reply #29 was a 6.8

The graphics are insane.
Very cool.
Thanks for the adhesive spray tip. :)

Tony


Title: Re: 8" F-16 CatJet Build
Post by: MKelly on August 14, 2019, 07:44:33 PM
Thanks Tony.  It came out at 8.3g after a coat of Aerogloss clear and some balance weight.  I did some test glides in the front yard - a little twitchy but after dropping the flaps a bit it started gliding nicely. Hope to take it to the field this Friday.

Thanks again for the kit!

Mike


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on August 15, 2019, 02:51:58 AM
Incredible Mike! You do realise this is a CLG :D

That is a neat tip re the repositional contact cement! It's a net way to finish over a sheeted balsa structure.

Watch out for the hunters in the tall grass,

John


Title: Re: 8" F-16 CatJet Build
Post by: MKelly on August 15, 2019, 09:45:25 AM
Thanks John.  For future builds I'm going to put the printed tissue on a frame and shrink it again before spraying on the glue and applying it to the model - I got some surface texture (small puckers) in the printed areas that didn't burnish down or shrink out when I doped the model.  It's only evident when you hold the model in your hands and look at it, but that's no reason not to take the extra step to avoid it...

Mike


Title: Re: 8" F-16 CatJet Build
Post by: MKelly on August 17, 2019, 07:46:42 PM
Allen and I had a good time flying the F-16s yesterday morning - video at:  https://www.youtube.com/watch?v=sQhaFyAdBEI (https://www.youtube.com/watch?v=sQhaFyAdBEI)

I put around 80 flights on the model.  Other than losing a missile rail in the grass while experimenting with launch angles (completely my fault) the model held up very well.  Best flights were 26 and 30 seconds, average flights were more like 10-15 seconds.  I don't think I ever really got the transition nailed, and glide showed a narrow range between stalling or spiraling in, but I had a lot of fun experimenting with cg and flap angles and got some quite satisfying flights.  Allen's model flew more consistently, but I don't think he was tweaking it around as much as I did.  I've replaced the missile rail and am looking forward to taking it out again and doing a more systematic attempt at sorting out the launch and glide.

We were treated to two 2-ships and a 4-ship of F-16s returning to Lackland during our flying session, and the barn swallows got quite a workout chasing the gliders.

Cheers,

Mike


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on August 17, 2019, 08:48:36 PM
We sure like flying the F-16's. This is really a nice revisit of the  flying session we had yesterday. I broke my missals off by accident but today I made two more and they are currently drying from the glue. The spur of the moment flying session was very enjoyable. Wish we could have more flyers the next time we try. These F-16's are really great flyers. The design is really well done. Thank you Tony for this thrill getter.


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on August 17, 2019, 08:50:01 PM
Thanks for that Mike. Good fun. Your model looks like a giant moth on the ground - no wonder the Swallows were interested :D

A great way to spend a morning.

Happy flying.
John


Title: Re: 8" F-16 CatJet Build
Post by: OZPAF on August 17, 2019, 08:51:26 PM
Flyace - you 2 fellows really make the most of it.

Cheers
John


Title: Re: 8" F-16 CatJet Build
Post by: tross on August 18, 2019, 10:24:03 AM
Thanks for that Mike. :)
Great flights. I don't recall any of those good flights on my first outing. ::)
Kudos both.
Those jets are flying pretty high!
Allen has his flying off the field. Nice. :D
I'm envious of the large open space. :o

Tony


Title: Re: 8" F-16 CatJet Build
Post by: FLYACE1946 on August 19, 2019, 10:43:45 AM
Flying the F-16 Jet Cat sure is fun. Isn't that why we do this in the first place? I thought so.