AJ1202

Hi I am bilding the T-38 Talon by Steve Shumate and was wanting to know if anyone has built this plane and how it performed. I am building the 120% version and using foam board from wally world, I have to say after the paper back is removed it's rather flimbsy but as you start adding the doublers and foam strips it gets much better. I was wanting to know how stable is the talon and does it have any bad habits. On a build note at first I thought the plans were some of the best I have downloaded as everything lined up very nicely to make the templates, however after cutting out all the parts and starting the build I found the sizes of some of the parts aren't right, some mods have to be made and parts have to be recut to match other parts
This is a minor thing but I was surprised by the amount it was off, even so I think this is a nice set of plans and look forward to completing the build

AJ1202

Well it doesn't appear that many people have built this plane sooo for those interested I will turn this into a build thread and post pics and comments about the build as I go. As stated previously I was impressed with the tiled plans as to them fitting together properly and making it easy to make the templates. I have cut all the parts and have now built the forward fuse, I am using foam board that is used for school projects or posters. I removed the paper by weting the board and scrubbing the paper off, this was a very aggrivating chore that I won't repeat, but I wanted to use black foam and this was all I could get. I am finding that because it is more flimbsy than depron I am going to have to reinforce it more than the build suggest. I will start posting pics once I get the forward half complete
OK here is the first pic of the forward fuse section

AJ1202

Got the aft section of the fuse built, I am using blue core foam as a doubler because as mentioned the foam I'm using is not sutible to be used by itself, IMO. I did find that if you floow the build exactly and not keep looking a page or 2 ahead or double checking the fit this area could have caused some heartache, in the directions it shows to glue the motor mount at the rear of the bottom fuse in the pic for that part of the build, however if you do this nothing will line up right and your whole tail section will be off, a couple pics later you see a recessed area between the rear of the fuse and the end of the motor mount, there is no mention of this as you go along. I still feel this is a very nice build and the directions are pretty easy to follow, you just have to stay ahead of yourself and test fit everything more than once before you glue it in
I am going to control my rudder different from the build suggest so there is no servo in the motor mount on mine. I am also going to wait on mounting the motor stick till later in the build

AJ1202

Well I joined the forward and aft sections and added the nose to it, I am working on the elevator set up now. I took a couple pics against other planes for size comparisons

DepronJet

AJ

have you choosen a motor and pack yet?

it looks like a nice clean build
and a nice size too [8D]

Ray

AJ1202

Hi Ray, no I haven't decided on a motor yet, I'm not sure where I'm going to be in AUW yet as I'm adding weight with the reinforcing during the build, I just hope I don't add too much weight and cause the wing loading to get too high for it to fly. I have decided to make the wing with airfoil, I know some say it's not going to help but I feel it does make a differenceI still want one of your T-33,,, budget just won't allow it right now [&o] but I know where to find it when it does

DepronJet

AJ

making the wing profile makes such a huge difference to the look of the wing,

it also strengthens it too
with regard flight performance i would say on a wide wing like the T-38 it would only be a marginal difference but visually very worth it [8D]

how are you going to do the profile wing?


i am working with a hobby store in the US so there could be stock near you soon

Ray

AJ1202

Oh man that would be great, well on the wing I was thinking about making a triangle config with CF tube and on the one spanning the wing lay a thin strip of depron over it then put the top layer of the wing over that, this would give me a nice very thin airfoil, I did something simular to another wing I built and it worked good

DepronJet

AJ

i tend to go the minimal route if you see the pics below it will make sense,
i have shown 2 wing types for anyone else who reads the thread

i use a 10 mm wide strip of depron along the wing,
this adds minimal profile and wieght also slightly enhances the lift performance,
then i put a 3mm depron skin glued over and to the 6mm wing,

a bit of sanding and its sorted !

dont beat yourself up working out the math and curves...
just make both sides exactly the same !
it will fly just fine and Dandy

Ray

clovus

Nice work Depronjet. Have I seen you over at RCGroups?

I was just wondering if the same technique could be used on the bandit as discussed on the nanojet thread over there.

clovus

DepronJet

clovus

my screen name over on RCG is Cadetman,
i must start using DepronJet

Yes it will work with the Bandit very well

Ray

AJ1202

Depron, that is pretty much the way I had planned, I just decided to use cf tube to reduce flexing in hard pull outs and manuvers

DepronJet

AJ

Keep posting pics

Ray

clovus

Cheers Depronjet,

And AJ sorry for the off topic post. I must say RCU is much more flexible then other sites that jump onto you with the slightest trangression, even if it is unintentional.

clovus

AJ1202

not a prob clovus, not getting as much time to work on this build as I'd like, hopefully I can get back to it soon

AJ1202

nevermind

AJ1202

Finaly got back to working on the Talon. I got the elevator installed, I decided to go with a stationary stab and flaps instead of the whole tail moving as I'm not looking for 3-D performance anyway. I have started the framework for the wing, I'm trying to keep the airfoil small so I'm going with 1/4" spars and using 1 CF tube along the rear one, I am going to sand the frame down to allow a smooth transition between the top and bottom wing panels and I think I'm going to have the aileron controls built internal instead of having servo's hanging out the sides, also on the elevator I decided to run golden rod to the just behind the cockpit and mount the servo there, this way I can build an access pannel and not have to extend the wiring

DepronJet

AJ

Looking good ,

if you are using elevators and fixed stab opposed to AMT you may need to put the CofG a little further back,
i have found that an All moving Tail model has a much greater range of acceptable cofg,

looking forward to the next pics and words

Ray

AJ1202

Well I have been busy and not had time to work on the Talon lately, BUT now it's time to get it finished. I have now decided on the power plant I'm going to use and will be ordering everything this weekend. Time to get er done

rhagen

Hi AJ,

I built the 120% T-38 this past summer. It is a fantastic flyer - the extra size really gives it a presence in the air compared to the normal-sized F-18 and F-14 I built. I posted build info in my blog over on RCGroups (don't know if posting a link is OK with RCUniverse, but my blog over there is under rhagen and the build is in the June, July, August archives).

You are right about some of the part sizes not being quite right - don't know what's up with that.

On mine, I used an additional layer of 2mm depron on the wing and stabilators, giving both about 8mm total thickness. This covers the carbon tubes, gives more strength, and looks better. Also, note that the 120% plans don't show the step in the upper fuse behind the canopy. This is a signature part of the T-38 and really improves the looks. I scaled it off the 100% plans and added it.

Mine came out at 27 oz ready-to-fly with an EFlite Park480 motor, 10x7 prop, 40A esc, and 3-cell 2100mAh lipo.
That combo doesn't give extreme speed, but the thrust lets it climb out of sight in a vertical roll! It is very smooth and graceful in the air and has no nasty stall tendencies. In fact, with a slight breeze I can almost harrier it the length of the field.

AJ1202

rhagen, that is good to hear, I like to hear good reports about others that have built this plane
I have had a few people tell how nice they fly. I will look into the step issue, maybe that's what I'm seeing that doesn't look right on mine, I was planning to cut the whole turdle neck section off and redoing it because something just doesn't look right, Thanks for pointing that out

AJ1202

Well I finaly finished my Talon. I decided to use the Blue Angles paint scheme on it. I think I am going to realy like this plane. I did crash it on the maiden flight, BUT not untill I had got a good flight out of it. I was coming around to line up for a landing and wasn't leading it well enough and let a tree get between me and it [:@] by the time I moved over to see it it had went into a nose dive and plowed the ground. It looked worse than it was, repaired it in a couple hours.
I would definatly recomend this build to anyone.
Here is the Vid of the Maiden flight [link]http://media.putfile.com/T-38-Talon-Maiden[/link]

ryan_t888

AJ, that's pretty sweet. I'm still waiting for you to throw a ducted fan in one of your jets. The fan from Great Planes puts out a lot of thrust for its size. How much does your Talon weigh?

Ryan

AJ1202

Ryan, I haven't weighed it yet but I'm thinking around 25 oz maybe 28 AUW
I have 4 different EDF at the house and I am playing with a set up now for one, I have my next build already set up and it's a twin. it will prob take me 3 or 4 months so the next jet might be a while.I think it will be a F-15 and ducted, I really liked my first F-15 I built, it was EDF at first but wouldn't fly as EDF so I converted it to prop.

ryan_t888

Ya, I remember seeing your F-15 in another thread. I believe you were using the weak GWS fans. The Great PLanes EDF outputs about 8oz of thrust per fan. Two fans should be able to push a 25oz plane with ease.

Ryan