Scratch Builders

[Gopher]

Do anyone scratch build large military jets (with retracts, flaps and lights as close to scale as possible)

I just want to see how others are building large (WS 38 inch and above) jets. here are some of my builds.

[Gopher]

Trying to add pictures...

[Jpahemi1]

Here’s my Su 27 scale is 9.25. Two Jetfan 110’s
landing gear designed and built by Matrix Machine.
93” long, 64” wingspan excluding middle rails. This is the second plane I built from the molds. Glass fuse, balsa sheeted foam wings and tail group.

[Gopher]

Jpahemi1,

Looks like you are a professional in building jets. Great job. I am a long way from skills like this.

I am just a armature foam builder, but I love the way you are building your jets.

Thanks for the reply,,,,,,,

[Jpahemi1]

I’m far from being a profession but I’ve been building for a very long time. Keep up the good work. The more you build the better you’ll get at learning new skills. I learned how to make fiberglass parts a few years back. This year I learned how to cut wing and tail surfaces from foam.

[Dirty Dee]

Designed and built a 1/11th scale A-10 for 90mm EDFs. Next project was a much simpler ERJ-145XR out of foam for twin 50mms. Recently (though not technically scratchbuilt) I made a 2 meter wingspan A333 via 3d printing with carbon fiber tubes in various areas for support. And very soon I will be finishing a U-2 for a 50mm EDF, also 3d printed.

[Gopher]

Dirty Joe,

Good job also.

All that balsa wood curves and bends are complicated. I am using depron and dollar tree foam, and some are laminated with dollar tree thin cardboard.

Pictured is my latest project, an F-22, 42 inch wingspan, length 60 inches, 70mm 6S dual EDF's, and flying weight 125 ounces or 7.8 pounds. I have not done a maiden flight yet.

If the dual 70mm EDF's are not powerful enough, I will upgrade with Freewing dual 6S 80mm EDF's. I have made patterns of all my builds and I also use the assembly technique to make repairing simpler.

Thanks for your reply.

[Gopher]

Jpahemi1,

I love your fiberglass fuselage and mainframe. I would like to know how to make fiberglass parts.

Are you willing to share info and know how to get me started?

[Dirty Dee]

Gopher, if you search on rcgroups the user "acesimmer". he has a few good build logs where he made a few fiberglass planes, and covers the process pretty well.

[Gopher]

Thanks Dirty Dee,

Acesimmer have 24 pages of posts on RCGroups. It's going to take me a little time to scan through them.

[Dirty Dee]

The most relevant would be his T28, Eurofighter, and Intruder builds

[Jpahemi1]

Gopher
I did a lot of research on Rc Groups and YouTube. I’ve also got two friends that are expert scratch builders that mentored me. If I can do it it’s got to be easy. The Su was the first plane. I started with the nose cone and moved on thru all the small parts first to get the hang of it. I did the fuse last. Came out good enough to use it.
Best of luck to you. I like your work.
John

[Alpha]

Gopher
I did a lot of research on Rc Groups and YouTube. I’ve also got two friends that are expert scratch builders that mentored me. If I can do it it’s got to be easy. The Su was the first plane. I started with the nose cone and moved on thru all the small parts first to get the hang of it. I did the fuse last. Came out good enough to use it.
Best of luck to you. I like your work.
John

John, superb looking Sukhoi! Those curves are not easy to execute. I had a Grummania years ago, 'loved it while it lasted.

To all you scratchbuilders out there, what are you using to evaluate airfoils, CG projection, etc? I'm curious what some of you use, because the results look impressive. As may be obvious, I'm used to using a suite a design tools and software, but I've learned that in certain cases the subject matter and size doesn't require too deep a tool set to fly well.


For anyone not yet aware, I recommend looking at John Morgan's scratchbuilds. Truly impressive creations over the years from a skilled craftsman.

[MikeT]

Plus 1 on John's builds. He's always got something in the works over on RCG. Dee's no slouch either his work is very nice and his work along with John's actually get into the air.
Mike

[Dirty Dee]

Thanks for the compliment Mike. Like Alpha said Johns builds are amazing, and he usually builds fairly large models, and convers ziroli's to electric. Other great builders like sparks, turbonut, corsair nut, antiarf (micro builds), air sally, Ianda217 to name a few.

To all you scratchbuilders out there, what are you using to evaluate airfoils, CG projection, etc? I'm curious what some of you use, because the results look impressive. As may be obvious, I'm used to using a suite a design tools and software, but I've learned that in certain cases the subject matter and size doesn't require too deep a tool set to fly well.

I use a mixture of tools and references. I always use a CG calculator and aim for 22-25% MAC. Straight single-panel wings are easy to calculate, but swept or multi-panel wings need the calculators usually.

https://rcplanes.online/cg_calc.htm

https://www.ecalc.ch/cgcalc.php

If a model exists of the model I am building, I usually overlay my model onto the picture of the manufacturer's CG picture in the manuals. For my A-10, I cross checked my CG against the Freewing 80mm A-10 as well as the FMS. Both seemed to match. For my A330, I checked against the Norbert Rauch build manual.

Lastly, I ask online in RCGroups or other forums. Lots of knowledgeable builders usually chime in like turbonut and Dan Savage.

[Gopher]

I started building years ago from RCPowers.com. I purchased the v4 package (Mig-29, F-18, SU-30 and SU-34). The CG is already determine in the drawings.

I enlarged each drawing mathematically (like foward/reverse engineering) which will keep the CG within a half inch or less depending on the size of the aircraft. I started enlarging to 32" wingspan and now I am up to 42" wingspan. I test each wingspan size as a prototype. I have been 60 percent successful in my maiden flights. I crash, repair, crash and repair until each size is fully successful in flight. Then I started adding dual rear mounted motors, then thrust vectoring, retracts, and other modifications while viewing these aircraft on YouTube. I am still learning and now I like the FiberGlass technique which John recommended that I research YouTube.

Thanks John.

[SidGates]

I am waiting for good weather to test fly my F-94C scratch build. All my builds are available at my web site: http://www.sidgates.us/HOBBIES/PROJECTS.HTM

[Alpha]

SidGates Exceptional work, thank for your sharing! The only time I've ever seen a Scorpion was sitting on a pole outside of Oshkosh.

With that straight wing and slender fuselage it should fly very nicely. Clear skies for your maiden! I wish you well, especially for this project that was 13 years in the making!

[quitcherbitchen]

Nice Scorpion, They use to have a squadron of those in Camarillo, CA near where I live. They were on alert 24 hours a day.

[SidGates]

Slight correction. The Scorpian was the F-89. The F-94C was the Starfire. I was stationed with the 27th Fighter Squadron, Rome-NY in 1956-1958. My paint scheme is the 27th F.I.S. My model is approx 1/6th scale. 82.5in long and weighs 21.5 lbs.dry. This is the first fiber glass fuselage I have done and had a lot of good advice from Dean Lassek and Ed Munoz, members of Jefco Aeromod'lers (Denver,CO). Dean designed the large scale A-10 that was in limited production.
If anyone has questions about fiber glass construction I will try to answer. Currently I am helping a good friend build a B-70, 15.5ft long with 6 turbine engines.