Skymaster T38 Talon
 

Not a lot of information out there on the SM T-38 so I thought it best to buy one for myself and do the honourable thing and post some more information. I wish the wife could see my intensions are for the benefit of mankind and not just myself :)

RE: Skymaster T38 Talon
 

The Wings are pretty much done, with only the pushrods to go, There is no dedicated manual for theT-38, The Skymaster site refers theF20/F5 manual as being the one to use, dont ask me why, the kit is totally different there are only a very few similarities betweeen them. the wings are not one of them.
Servo compartment is pretty tight, on the F20/F5 it is stated to use JR 3301 as aileron servo's and given the size of the T-38's wing these would make for an easy install. But seeing I am stubborn and difficult I chose full size JR 8231's. With a bit of work they fit, JUST. Flap servo's fit without too much work, they are JR 8511's.

RE: Skymaster T38 Talon
 

Phil,

Always wondered how the T-38 flew. I assume it flies like an F-5 -narrow long body with a pointy tip and small triangle-like wings :D- which is probably why SM never bothered with a manual. I bet their F-5/20 + T-38 + JAS-39 combined net less sales per year than a month of Viperjets.

Question: Noticed that the control horns on the control surfaces shown (Aileron + Flap) are well done at perpendicular and 90 degrees to the hinge-line. But the aileron servo arm looks like it is not even with the it's corresponding control horn. That is a recipe for disaster in the long run unless you are thinking of using ball-links, and even then, it's less than optimal. Is there a way to mildly rotate the servo so the arm and control horn have better geometry between them?

What power-plant will you be using? I imagine a New JetCat P140RX would be ideal, or even the P160SX with intelligent throttle usage?

Best of luck bud, keep us posted. Cheers,

Shaz

RE: Skymaster T38 Talon
 

Hi Shaz
Trust me, its an optical illusion. The horn is perfectly in-line with the servo arm.
Sorry no Jetcats here. It will be powered by something from the Jets Munt stable.
Phil

RE: Skymaster T38 Talon
 

Elevator:
The elevator assemblies are fairly straight forward, however one of the bearing recepticals was a little large for my liking, no big deal, a layer of aluminium tape made the perfect shim.
Servos are JR8611 with aluminium arms (A definate must given the location and workload) mounted to the supplied Aluminium "L" brackets, and bolted to the elevator plate with captive nuts. A little fiddley but with your tongue in the right position, it is easily achievable.
One thing to note is in the hardware kit supplied is 4 nylon washers and if you go by the F5/20 manual one of these nylon washers go either side of the inner and outer bearing (incidently the F5/20 uses a bushing type bearing and not ball bearings as in the T38) Both these nylon washers are needed per side to go between the outer bearing and elevator root section to provide the required elevator to fuselage clearance. A suitable washer will then need to be sourced for the inner bearing, just make sure it only contact the inner race of the bearing and not both otherwise it may bind the bearing a little.
Better quality pushrods were used as well as bearing type rod ends front and back.

RE: Skymaster T38 Talon
 

Rudder (Sorry no picture):
The servo, a JR8411 is accessed via the root section of the rudder which needs to be cut out. This differs from the F5/F20 which has a servo hatch in the side skin. Anyway the T38 version is much cleaner with only the pushrod assembly exposed. Its a bit of a shame really and quite easily modded should you wish to have a totally enclosed linkage, me being stubborn, difficult and now lazy took the easy route. Inside the rudder you wil find an empty void, you will have to fit your own servo mounts if you take the same option i did.

RE: Skymaster T38 Talon
 

Hi Guys,

I have a SM T-38 almost done, some iphone pics attached here, if it's helpful I can take some better ones later and post. My son is down at USAF flight training at Sheppard AFB, just finishing with T-6 IIs and about to start flying T-38s, so of course I had to have one! SM offers the gray on gray camo scheme that the Sheppard birds use, so I had Matt take some pics of the planes on the ramp, and SM did the tail art and numbers to match one of them. I am hoping the camo scheme won't disappear in flight (but as a friend likes to tell me, "that's the point, dummy!").

The build has been pretty straightforward, I did have a small issue fitting a full-size servo into the aileron pocket as noted above, there is a tiny bulge in the top wing skin that bugs me a little but no so much that I am going to put a smaller servo in!

One thing that I am still thinking about how to deal with is the fit of the stabilizers in their bearings. As-supplied the brass "axles" had a fairly rough finish and had to be slightly reduced in size to get the bearings to fit. I did this as carefully as I could but once the bearings went on, there is a tiny amount of slop that I am not really happy with. Considering some green locktite (which I believe is intended for this purpose), and I've read here on RCU that some people used thick CA in the gap (and presumably making stab install permanent!). Also wondering if the miniscule slop is actually ok. My only other similar install was in a Yellow F-18, where the axles are machined titanium and the fit to the bearings was dead-perfect.

My current plan for power is a Wren 160, which will call for some prudent throttle management! I was just doing the final equipment install with an eye on the CG, doing battery placement etc. With the 160 sitting in the motor mounts, she weighed 27# with all the tanks and UAT dry. I thought about using a smaller motor to get a slightly lighter plane and perhaps longer flight time .. but the next increment down for me would be a Wren 100, about 22# and I think the pipe inlet is too big (3.5") and the bifurcation would steal too much power, and who wants an under-powered T-38.

I've had some conversation with folks who have flown these, and they report that the T-38 flies very well, and actually does not land crazy-fast .. it's scary just looking at the (teeny tiny) wings, but it's clear that the fuselage probably has more "wing area" than the wing!

Dave McQ

RE: Skymaster T38 Talon
 

Nose Wheel Steering:
This was a little strange, for what is supposed to be a premium kit ie: still on the Skymaster main page and not on the Extreme page.
There was no provision for a nose wheel steering servo, again the F5/F20 manual shows a servo fitted to plywood mounts in the fwd nose section but the T38 has an empty nose. Now its lucky that I have built 1 or 8 skymaster kits before and unfortunately not all have survived but fortunately a steering servo mount assembly was reused here. It fits really well clears all internal formers without modification and if my opinion counts, this type of mount should be supplied. One thing to note in the photo I have the servo fitted in a conventionally mounted way, this will be reversed so that the extra height made by reverse mounting will give enough clearance to the nose gear door when closed with gear down.

The second and third photo is not what was fitted to the T38 but a similar unit, for better clarity of how the assembly looks before fitment.

RE: Skymaster T38 Talon
 

Cockpit Detail:
One thing I hate, Is fitting these overpriced pieces of recycled credit cards. The cockpits supplied from Skymaster are the worst. They are always too flimsy, they never fit easily and if your not careful handling it you will end up with a cockpit jigsaw puzzle. The supplied T38 cockpit detail was no exception, I had to reinforce the outside of the tub with 2" glass ribbon and reglue just about everything on the inside of the tub.
If your considering a T38 with cockpit detail, do yourself a huge favour and build it first before you do your servo tray/component fitout. Now I wasnt caught out on this kit but I have been caught out before, the cockpit tubs are full depth, you can pretty much fit your complete pilots in without too much trouble (more on this later). With the cockpit assembly fitted you have approx 0.5" of clearance between the cockpit tub floor and the servo tray, so forget about having all your components mounted on that fwd tray with the full cockpit detail.
I like to have the entire cockpit assembly come out with the canopy, it takes a bit of work to do this but once in and secured it takes the frustation away at the field.
Now back to the pilots, It would seem that my pilot (fwd) was a little taller than the max height allowed on the T38 as he needed to have about 0.25" removed from his mid section to fit under the canopy. Under the clothing reveals a nasty scar and I doubt he will ever drink without wetting his Tee shirt, but with the flying suit back on he looks the part only shorter. But he fits in nicely.

RE: Skymaster T38 Talon
 

Philjac,

Very very nice work! great idea on the nosegear .. I mounted the servo in the nose, but your setup as waaay nicer. Agree with the cockpit comments, yours came out great!

Dave

RE: Skymaster T38 Talon
 

Fuel Tanks:
CHECK YOUR TANKS!!!! If you thought you would pay for the upgraded Kevlar tanks and also think that because you went premium you would receive 100% leak free tanks, dont bet on it. My main tank had 2 pin holes just above the seam line, not that the location matters.
The tanks (Kevlar) are not a very good fit, they are not a purpose built tank for the T38. To get both tanks in level, the upper turtle-deck tank needed to be gently heated and remolded to fit higher in the turtl-deck. If you do this, as a safety measure, re-glass the remolded area because there is a good chance the epoxy is stressed which may cause a leak. There is not much of an option other than to silicon the tanks into place.

RE: Skymaster T38 Talon
 

I have been flying my Skymaster T38 for a couple years. They fly and land wonderfully nose high. The elevator stick is now almost full up on touchdown. With RTI motor I have shot the T38 at 198 straight and level flight. It is a real pleasure to fly.

Good luck with yours!

RE: Skymaster T38 Talon
 

Not a big post here but this is my chosen location and method for air line quik-connects. They are actually the type supplied with Feibao kits made by Airpower. With the right sized drill hole the solid end of the quik-connect is inserted and glued to the wing root. The knurling gives plenty of surface area for the glue to hold onto, and if you get your hole sizing right even CA will work well enough.

Ok, thats about it for now will post more of the build as it happens.

RE: Skymaster T38 Talon
 

Looks great Dave, I really like the scheme! Despite the camo, I bet the variation in colors will be fine in flight.
Your fears about the itty bitty wings vs the long fuse were the same I had with the F104. Turns out the fuse does give a lot of lift, and I bet on the t38 even more so. Can't wait to see this model later this year.

RE: Skymaster T38 Talon
 

Dont fear the wing being small. The fuse produces almost 40% of the lift for this airplane.

RE: Skymaster T38 Talon
 

One of my favorite planes of all time... It is on my bucket list.

RE: Skymaster T38 Talon
 

Thank you for posting this I love the plane , but as you say not much mentioned on it

Dave

RE: Skymaster T38 Talon
 

Would love to see a picture of the rudder servo set up. Been scratching my head on that one.

RE: Skymaster T38 Talon
 

Sorry Dale, you are sh1t outta luck with a photo of the servo nestled in the fin, now it is installed, but here is a photo of the linkage setup. It shouldnt be too hard to visualize the servo. It is mounted upside down so that the servo horn is accessable from the root section of the fin.

RE: Skymaster T38 Talon
 

Great build..I love the T-38 soo much I scratch built one..a BIG one.. : )

RE: Skymaster T38 Talon
 

ED my favorite scheme. Great Job Falcon5

RE: Skymaster T38 Talon
 

Here is my rudder setup.

Dave

RE: Skymaster T38 Talon
 

Thanks, that helps. The Skymaster instructions lack a little to say the least. I thought they just forgot to cut out the bay for this one. Wonder if you can get one the servo steering mounts from them. Could make one but would be easier this way.

RE: Skymaster T38 Talon
 

I love the T-38 Talon. They are beautiful.

They just need a lot of room to fly ... especially altitude. Don't ever attempt a tight loop. It will easily snap-roll on you. Once that happens, it's all over unless you have at least 600' of altitude to recover. From my experience, the loop should not be tighter than 400 to 500 feet. (Estimating, of course.) My F-16 can perform tighter loops, but the Talon seems to need a wider loop.

RE: Skymaster T38 Talon
 

HI, I'm not a jet guy but I was an Aircraft Electrician in the Air Force back in the 80's and worked on the T-38. Thanks for bringing back some good memories. It really looks good.