Mattholew

Hey guys,

I have a Sr. Telemaster with a Zenoah G20 gas engine on it. I love the engine and the plane is great at what it does, but I want a little more aerobatic performance and wind resistence when needed. Im not looking for pattern, 3D or extreme aerobatics, just better sport aerobatic capability as well as getting rid of some of the "floatiness" of the huge wing. I want to keep the ability of heavy lifting, glider tug, banner tow and bomb drop duties also though.

So what should I do?

Shorten the wing, and reduce dihedral?

Replace the wing with a different one? Possibly using a different airfoil and span and keep the original 8 foot wing also?

I would appreciate any opinions on this matter.

Thanks,

Matt

Campy

My Feedback: (1)

>Yoou are talking 2 different things here. What will make the plane more
>aerobatic (shorter wing, less dihedral ) will reduce the heavy lifting, glider tug
>and banner towing abilities of the plane.


>I would build 2 wings. A shorter wing (perhaps eliminate 1 or maybe 2 bays on each side )
>with less dihedral and a semi-symetrical airfoil and a stock wing. Then use the appropriate
>wing for what you want to do that day.





fixed to separate out quotes- bmatthews

Scar

My Feedback: (3)

Campy makes some good points. The second wing suggestion is good.

My suggestion would be to buy a more aerobatic plane, have a Four-Star (or an Avistar, or a Tiger) for days when you feel like doing aerobatics, and the Tele for days you want to fly a Tele.

Just my 2¢ worth, Good luck,
Dave Olson

Mattholew

Thats what I was trying to get at, I think I need two wing. I didnt state my question clearly enough.

I need the stock wing for lifting and days when the wind is calm and I want to float.

Other times I need a faster wing.

So my ultimate question was:

For more aerobatics, should I shorten a stock Telemaster wing or build a different wing, using a different airfoil also.

Mattholew

Unfortunately I cant afford to outfit another airframe right now, expecting my third child in a couple of months.

Thanks for sharing your opinion with me on the matter though.

aerowoof

both shorten the wing a bit ,remove some of the dihedral and change the airfoil to sem-symetrical.I have one that is used on northeast aero-dynamics models that has enough of a flat section that you can build it on a flat surface.

BMatthews

Truthfully, I'd also suggest a new model.

But since that's not really practical right now...

A lot of how a model handles the wind has little to do with design and much to do with trim. Altering the ST to work the CG more rearward would reduce the effects of flying in the wind and the tendency to climb strongly with added power.

However the airfoil is a rather high drag sort of shape.

A new wing with a reduced camber and perhaps one rib bay smaller on each side would perk it up quite a bit. No need to go TOO small. Use the trim for that. The main improvement would come from the airfoil choice. I'd suggest something that looks more or less like a NACA 2212. And you can certainly reduce the dihedral to just a hair or nothing (flat). A lot of folks tend to leave in about 1/2 to 1 degree of dihedral since a truly flat wing on a high wing fuselage often appears to be drooping. I'd also suggest that to add some fun to this that you make the ailerons outboard conventional ones and add flaps inboard. The outer 40% being ailerons and the inboard portion the flaps. Should make for some interesting testing. For a sporty feel I'd suggest the ailerons and flaps be sized to 20% of the chord. To keep the weight in check you'll also want to make these surfaces built up.

Keep in mind that to get the most out of this you'll want to trim the model as suggested. Do a search for "dive test" for lots of past writeups on this technique. One aspect that you'll want to watch for is that reducing dihedral also affects the spiral stability of the model. If you find that the new wing wants to roll into and tighten the turns then your fin is too large for the new setup. If this happens and it's quite strong you'll need to trim down the fin size a few %. Fortunetly a little goes a long way here so it likely wouldn't need more than 5% taken off if this happens. But keep it in mind. Such things are just one part of why often a new model is better than trying to significantly modify an old one.

In fact you may find that you like it so much that you don't go back to the old wing.

Jim Messer

My Feedback: (2)

Hi Matt:

The Sr. Telemaster was designed to float, and is a magnificient "trainer" airplane. It was never intended to be aerobatic, and there isn't much you can do to it to make it that way. So my advice to you is to leave it alone and enjoy what you have.

One major problem is that it has a "lifting tail", much like a free-flight airplane. That allows the CG to be further back than normal, and you can get by with that on the flat airfoil. However, if you change to a semi-symetrical airfoil, the CG needs to be a lot more forward, about 25 to 30%. If you leave the CG further back as it is now, then the new wing wont fly right either.

Don't waste your time. Build a whole new airplane. The day will come when you can afford a second radio system - used ones are getting cheaper all the time due to the many modelers switching to 2.4 GHZ. systems. Go to a swap shop, make a ridiculous offer, and have your money ready because you will probably get it for your price. In a few short years I predict that you won't be able to give away 72mh. systems.

Piper_Driver

Don't mess with the Sr telemaster. The Lifting Stab is matched to the current wing.

Making a clipped wing would mess that up. And I have seen the tail fall off the arf sr when going to fast.

I use three aircraft for different missions.

Lazy day/photo/slow touch and go's/tail slides / lounge chair flying/ 45min flights Sr Telemaster

Basic sport/ easy aerobatics 4 Star 60


3D Funtanna S40 with 50X winglets

haikt

My Feedback: (11)

Play around with your plane, dont hesitate to change it, after all that is the great part of this hobby. When I got into RC many years ago I had a KADET 25LT, I learned how to fly on it and after short time was board, wanted more fun out of the airplane. having only MDS25 on it people told me that I could not do anything with it and to go and buy a new model something with a four stroke or a big engine to have fun...... I was in highschool then and could not afford a bigger engine or a new model so I first cliped the wings 2 inches and that did not make much change. I cut it back all the way to half of each wing half and got somewhat what I was looking for. I took the angle out and bolted the wing on.
Long story short I made so many changes at that you could not tell that it was a trainer at some point. I understand that you want to keep best of both worlds which makes this more chanenging but to me that's the best part. Test it and have fun with it. to tell you the truth I probably have not had so much fun with any plane as much as I had wuth that trainer.
And this is what I am working on now little crazy but I am having fun.....[&:]

vmsguy

I have to agree with many of the people who have added to this thread.

1. Don't be afraid to modify your airplane. BUT, be prepared if your modifications don't work out the way you want. Be prepared for making your plane unflyable. If you're willing to pay the consequences, then take the risks. Can you live without a plane while you make the mods? Can you live without a plane if your mods go very south and you end up crashing it?

2. The Telemaster, is not a wildly aerobatic aircraft. You're not going to get mind numbing speed, or gut wrenching maneauvers out of it. So if that's what you're looking for, save your money and get a different plane. Maybe move the engine and radio equip from the Tele into it to save costs.

I guess it boils down to.. what are you looking for, and what risks are acceptable to get them? Only you can answer those questions.

dumorian

My Feedback: (6)

I would first double the size of the rudder. Next I would add flaps. Just cut the ailerons leaving about 2/5ths for flaps. Set it all up for max throws. Oh, you will want to be able to use full span aileron settings on your radio or something like that. Basically, have the ability to use the flaps in co-ordination with the ailerons.

Then you could easily cut a set of straight wing spars. There would be a bit of a gap where the wings come together at the top, but that won't effect flight. Then beef up the struts... make sure they are really working and very strong. Throw maybe 20 rubber bands over the wings and have some fun!

Flaps are great for getting this bird to land. The rudder is too small period. There are crosswind situations where you simply cannot control the plane on the ground once the tailwheel lifts. Doubling the rudder should fix this. You may need to review the control linkage. The stock linkage is 'good enough' for factory settings, but I think they would be too flexible for pushing it. The larger rudder is almost a certainty.. might need a larger servo for that as well. Pull/pull would be nice.

If this is an ARF, you might want to consider sheeting or at least bracing the rear portion of the fuse. Give it a bit of a twist with your hand and you'll see that it is not really all that stout. Again, plenty good for what it was designed to do, but... if you want to push it, you should be prepared to add some strength to it.

I had a STM. Lost due to radio glitch. I had it all decked out. Tug release, 3 bay bomb drop, marker and landing lights, flaps... The next mod I was going to do was the rudder. When deciding what to do for a replacement, after much consideration, I decided to do a Dynaflight Super Decathlon. Only bad thing is that one is going to be a gasser but I have a 4M glider which will make a good home for the STM electrics.

Rodney

I've built several of the Telemasters and all flew great. The three biggest changes I made that seemed to pay off were: !.remove all the dihedral, 2. increase the size of the rudder by at least two or three times, and 3. Stiffen up the wing structure by either sheeting the wing from the spar to the leading edgeboth top and bottom (make a D leading edge) and/or adding X bracing between the ribs. By X bracing I mean adding cross bracing that goes from the juncture of a rib and the trailing edge to juncture of the next rib and the main spar. If built per plan, the wing is easily twisted so anything that gives additional torsional stiffness will be a big help.

FLYBABY6

yup, wrong plane to get what you're asking I would think. Or you can modify all of its character and change the way it performs, in which case, it's not a telemaster. So.. with the changing it idea, sweep the wings back, how much I couldn't tell you, make it lighter, and less dihedral front and rear. um.... yea... would be better to make what you want from scratch..

Telemaster Sales UK

If money's tight, why not build a new model from a plan. A Citabria will give you all the qualities you are looking for, a Telly will never be very aerobatic.

Let me put it this way.

A racehorse and a carthorse are both bred for a specific purpose. It would be possible to cross a racehorse with a carthorse but whether the offspring would be any good for anything is another matter!

Happy Landings.