T-28 True 1/5 Scale
 

The purpose of this post is to verify my belief that there is a fairly large number of scale moderlers out there interested in building a true 1/5 scale T-28. Correct outline etc. And what type of a kit would be best suited. Plans, Plans w cowl and canopy or full kit. I am in the final stages of construction on just such an project. Just waiting for the cowl to come back from fiberglass specialities. 98.75" wing, weight 30-35#. Plans were hand drawn and are in the process of putting in cad. Wing was first item to do in cad and was totally cut out on lazer. went together very well. Fuse etc, drawings are about 85% completed. After we have flown the prototype we will make any necessary changes and cut a full kit.
Your imput would be greatly appreciated.
I have attached a couple of pics of the almost completed project. (90% built, 50%completed)
JohnnyO

RE: T-28 True 1/5 Scale
 

I would be highly interested in a short kit type kit. Ribs/formers/'glass parts/canopy would be great in a package. I assume retracts would be readily available from one of the retracts companys?

RE: T-28 True 1/5 Scale
 

Jeff...

I think Bob Holman has had plans for the large size T-28 available for number of years. He has laser cut parts coming up too.


Wm.

RE: T-28 True 1/5 Scale
 

Bob Holman's mammoth scale plan is not very good. The cowl is too short , the canopy is too high, all the controls are exposed, ailerons and flaps are wrong size. Not very goods and will not be any way near as nice as Johnny's.

RE: T-28 True 1/5 Scale
 

Very nice work, I am in the process of getting my Iron-Bay 1/5th scale T-28 in primer. As you said 90% complete, 50% done. My joy of building really gets going after that first prime coat. When all the surface flaws are taken care of and I start laying out the panel lines ,hatches, and rivets. Robart makes a complete set of retracts for this plane. Iron -Bay has a set of wheel brakes that go along with their tires and wheels. I am giving them a shot. The brakes were first designed for the big F-15 model Byron had. Same wheels as the T-28. The steering system that Robart designed into the nose gear retrack is great! No cable steering on this bird to fight with. Has a tiller arm. The plane has been a breeze to build. It is great to see some one else get into the larger T-28 market. Good luck with your kit sir.
Gary

RE: T-28 True 1/5 Scale
 

johnnyo
met you at bandits over kansas (i am the one with the 1/3 pup) myself would be interested in laser cut short kit, plans, glass and canopy
keep me informed when availible
todd

RE: T-28 True 1/5 Scale
 

The retracts are modified Robart units designed for the original Byron. I have a set of the origional Mammoth plans. They are ok for a sport scale, I was looking for something alittle more competitive. here are a few more pics taken in the process. Short Kit? Basic ply parts, cowl and canopy, plans ect., no sheeting, correct.

RE: T-28 True 1/5 Scale
 

yes basic shaped parts no sticks or sheeting

RE: T-28 True 1/5 Scale
 

Would a "D" model be available

Lew

RE: T-28 True 1/5 Scale
 

The T-28 D is just an "A" model with the "B / C" engine and cowl. The cockpit radio panels etc. are different but the basic airframe is the same.

RE: T-28 True 1/5 Scale
 

I might be interested in a short kit as well. Keep us posted!
Bryan

RE: T-28 True 1/5 Scale
 

I've had a love affair with the T-28 since I was a young teen-ager.....even built a Berkley T-28 UC.....that lasted one flight when I tried a wing over and it didn't pull out :(

Built the Pica 1/6th and 1/5th (really 1/7 and 1/6th) kits....beautiful planes!

Jerry

RE: T-28 True 1/5 Scale
 

Hal, is correct. The kit could be modified to just about any of the T-28 variations. With a new cowl you could even do the turbin version, on the last turbin #3 version, you would have to lengthen the vertical stab by about 2.5".
Looks like a short kit might be the right offering.
Plans
Instructions
Cowl
Canopy
All shaped wood, other than balsa blocks for shaping, such as wing tips etc.
Who's gear would you all prefer. Sierra, Robart, Custom built ????
Here are a couple of pics of the hinge set up. These hinges are laser cut from G10 and are avaliable in two sizes. 1/5 and 1/6 scale. work great on the Dave Platt or Moser kits. Will work for any ac that uses this style of hinge arrangement.
johnnyO
PS I'll try to keep those interested up to date. thanks

RE: T-28 True 1/5 Scale
 

on the gear, i dont think it matters provided they are strong and AVAILIBLE if you catch my meaning, wouldnt want to be on a list that takes a year to get the gear

RE: T-28 True 1/5 Scale
 

I think for a true scale aircraft, Sierra is going to be the way to go, seconded by Robart.
Bryan

RE: T-28 True 1/5 Scale
 

The T-28 main gear struts are angled 3.5* towards the FRONT. This requires that the retract pivot block be drilled at an angle or a piece be made with male/female ends that are at the same angle ( 3.5*) . Darrell at Sierra is aware of this feature. Lenny Sarbin ( Shindin Machine ) makes an adapter that was made for my Platt retracts . I am sure he could make a larger one for the 1/5th scale.

RE: T-28 True 1/5 Scale
 

Gary, a couple of questions regarding the iron bay. Did they provide a lower gear door attachment kit??? Or did you need to make something up. Also the gear that Robart makes for the iron bay is what I am using. However they were 90 degree, which when retracted would go through the top of the wing. Is the top of the wing open on the Iron Bay were the wheels retract? I had robart send a set of 85 degree blocks from their P47 gear and they worked out just right. With my wing design I also had to modify the trunion to get a 3.5 degree forward sweep in the gear leg, without the sweep, the gear came up way to far back in the wingl.
johnnyO

RE: T-28 True 1/5 Scale
 

The wing center section out to about half of the flaps are apart of the fuse, wing stops just past the landing gear mount., so the wheels go up into the fuse. did not even think about this. Those good old boys at Byron's have come up with some neat ideas. They are quit deep in the wheel wells. I have now primed, filled, sanded, primed again on mine. I then found a couple of pin holes that did not get filled properly, so have to do it one more time. I have found a great time saver for the sanding part. My wife bought me a Black and Decker Mega Mouse sander that is an orbital sander allong with a standard sander with small detail foot. I used 220 grit discs on the orbital sander and cut the sanding time by 70%. Hate sanding. Anyway should have the final prime coat on it so that I can start laying out the panel lines and rivet detail. These things have a bazilion button head rivets on it. The only flush rivets our on the leading front part of the wings.
Yes they di provide a lower gear door attachment system, utilizing there wheels. Again mine has the brake system on it also. Can not wait to see that nose droup when the brake is appiled...LOL
Keep the progress going.
Gary

RE: T-28 True 1/5 Scale
 

Johnny,

My first encounter with full scale heavy metal was in a T-28 "A" model over 40 years ago. I would certainly be interested in plans, cowl, canopy, and either templates or laser cut ribs and formers.

If anyone has access to accurate cowl cross-sections, I would really like to build an "A". I know, it had a puny 7 cylinder engine but that cowl was more streamlined and the USAF and ANG trainer version just doesn't look right with the big cowl. Besides, once you got the "A" all cleaned up and moving along, it was probably the most honest bird to fly that anyone ever hung a prop on.

Now if I just won powerball...and could get a medical again...I would buy that "D" that is on Ebay and quit fooling with RC scale. (If wishes were horses, beggars would ride!) Thanks for starting this build and best of luck. If you have never done one of these before, you will be in for a pleasant surprise when you fly it. Some kits have tried to duplicate the combination of downthrust and incidence angles on the full size bird and wound up with one that has to be re-trimmed constantly. This may be an area to evaluate once you have it flying.

Best regards,

RE: T-28 True 1/5 Scale
 

Thanks for the kind words. I have finally recieved the cowl from Fiberglass Specialties, I must say they did a great job from my plug. I try to post a few pics soon with the cowl mounted. All of the deminsions are correct on this project, wing is 3* positive at the root and 0 at the tip, 4* down thrust in the fire wall and 1* right thrust in the vertical fin. With 7* of dihedral, I think it will fly just fine with the CG set at 27-28% of MAC. Power is a GT80 swinging a 24-10 two blade. hopeing the finish weight will be in the area of 35#s. Next project is getting the scale exhaust done, then it is time for a test flight. Everything is servo'd up, etc.
There is now a cowl availabe for this project from Fiberglass Specialities and we are looking at doing a short kit that would include laser cut formers etc, canopy, full size plans and instructions and cowling from either us or FS. Have not come up with pricing as of yet. Want to get a few test flights to make sure it is a good concept.
JohnnyO

RE: T-28 True 1/5 Scale
 

JohnnyO,

Thats a beautiful bird!! I have been watchin this thread and glad to see movement and await the results!

Are you going to also offer it in 1/6 scale?:D

RE: T-28 True 1/5 Scale
 

JonnyO, hows your T-28 comming? Just finished mine. Came in at 37 pounds dry. Here is a photo of it. Will begin flight tests soon.
Gary Webb

RE: T-28 True 1/5 Scale
 

Yat, Its coming along and hopefully will be test flying in the next 30 days. Have no desire to do a 1/6 as there are a couple of pretty good examples out there already. (Dave Platt and Vance Moser)
JohnnyO

RE: T-28 True 1/5 Scale
 

Gary, very nice job. You seem to be a little faster than I. What engine are you using? Have you had a chance to fly?
I'll keep everyone up to date with a few pics etc this weekend.
JohnnyO

RE: T-28 True 1/5 Scale
 

I am using a Phil Sphear 4.6 twin on glow and alcohol. Have not flown it yet. Hope to soon.
Gary

RE: T-28 True 1/5 Scale
 

Gary,that should handle things nicely, I'll post pics this weekend with the cowl etc.
JohnnyO

RE: T-28 True 1/5 Scale
 

Been working on setting the cowl and mock-up for the scale exhaust. Mock-ups are done and the cowl is mounted. Here are a couple of recent pics. The cowl in the picture was just temperaily mounted for a scale event we had. Has since been mounted with a little more down angle. Also modifying the carb intake more closely to B. should have additional pics. soon.
JohnnyO

RE: T-28 True 1/5 Scale
 

Let's try this. See if we can't get these pics posted.
JohnnyO

RE: T-28 True 1/5 Scale
 

I have a set of plans, cowl and canopy from Mammoth. Looks like a lot of work. Looks like the one JohnnyO is doing is really nice. Does anyone know of any pictures or someone that built and flown the Mammoth T-28? I hate to just let these sit around.
Thanks for the help.
I will stay posted on JohnnyO's T-28 anyway.

RE: T-28 True 1/5 Scale
 

hallo Pitts3

It is indeed a lot of work to build that trojan. Wing design does`n fit to the fuselage .Air intakes
on the cowl are too small.Dorsal fin is too small an so.if you have good 3 views you can change
it all. I think Johnnyos Trojan is more up To dade and true scale.My mammoth T-28 did´n fly till now.
See pics "best scale photo" in this forum.

RE: T-28 True 1/5 Scale
 

One in primer. Belongs to Mr. Del Dunmire

RE: T-28 True 1/5 Scale
 

More,

RE: T-28 True 1/5 Scale
 

I may also be interested in a SCALE D model... Dave Platts is Close to scale isnt it?

RE: T-28 True 1/5 Scale
 

Johnnyo, flew my T-28 for the first time at the DOGS show after hours. Frank Noll at the controls. I then flew it myself. It flies just like my Pica T-28, only better, due to larger size. Flies just real solid and very little trim changes. Flaps just slow the plane down with just a little down tuck when fully deployed. This was with no expo and all throws set at recommended throws from Iron-Bay. Will love flying this one. No nerves flying war bird.

RE: T-28 True 1/5 Scale
 

drdoom, have many detail shots of this ac myself as I live in OP ks. This ac is an F model (Fennec), Which is a modified A model. The D model is same as a B, but has wing hard points for stores and in some cases additional strakes along the cowling. Those couple things are the only differences that are noticeable.
My plans can be modified slightly for any of the T-28 models. The A and TA models would of course need different cowlings and the A would also need higher profile canopy.
Johnny O

RE: T-28 True 1/5 Scale
 

Gary
Great. Sounds like everything went as planned. I believe my weight well be close to what you had told me yours end up at. So should fly similar with the GT80 for power. I assume you had plents of power?? What does Iron bay recommend as the control throws. I will need a starting point.
thanks
JohnnyO

RE: T-28 True 1/5 Scale
 

Drdoom, met to say, yes Dave Platts 1/6th scale is pretty good and there are a few out there flying. If you decide to do the Platt, I manufacture a set of scale flap hinges for this size T-28 as well as the 1/5 scale.
JohnnyO

RE: T-28 True 1/5 Scale
 

Johnnyo: I hadn't noticed the OP, KS connection, Looks like you will have a real sweet machine.
They put the T-28 In a hanger across from mine at Harrisonville, and Now it will be hard to get to. Believe it or not, they are going to polish it out!!!
Personally, I think it would look better Painted.
I would like to come by some evening and see your Plane. It looks Great.
I live in Lee'sSummit, But work in Belton.
Keep us Up to date with Pix. Everyone loves the build thread.

RE: T-28 True 1/5 Scale
 

JohhnyO, I used the suggested throws in the manual of the Byron T-28.They are as follows: Ailerons=3/4" each direction, Elevators= 1" each direction, Flaps =
3-1/2" to 4" down measured at the centered aileron root, Rudder= 1-1/2" to 2". Control surface incidence, cockpit level...Wing 3 degrees positive (measured next to leading edge strake). Stab. 4 degrees positive. Thrust 4-5 degrees down.
Balance 4-1/2" measured at outboard center section.
As for power, plane flies mostly at half throttle. Lift off at 2/3rds throttle on hard surface. Needs 10-15 degrees of flaps for take off.
My reference book says the T-28 max flap down position is 37-1/2 degrees.
I set my low rates at the above rates and then added a little more to high rates. Found low rate ( recommend rates) were right on.
My 78cc twin is running on alcohol, and is converted to glow like the racing planes. I use methanol alcohol and 5% klotz oil. This equates to 6 oz. oil per gal.
I am using a Menz 22/12 Ultra prop. I think a 22/10 would work well also. Plane really flies very stable. Where ever you put it it goes. Flies like a large slow pattern plane. Very docile. I have yet to try the air brake. From what I have gleaned from my reference book, it was used on landing to give the plane a high sink rate like a jet. Also, the down thrust and lower nose wheel makes the plane have a long take off roll to help simulate a jet take off. This is why the flaps are necessary to get the plane to rotate quicker.
hope this helps.
Gary

RE: T-28 True 1/5 Scale
 

DrDoom, you are more than welcome to come by some time and take a look. If you would send me a email, I'll give you my ph number.
JohnnyO