I am getting pretty comfortable in my trainer and can do touch and go's, landings, straight level flight, etc. pretty confidently. I have started doing some basic stunts like hammerheads, symetrical loops (well almost), and inverted flight fairly well. I have read several postings about people who broke the wings on the trainer due to too stressful a manuveur on the plane. My question is, "What can't the trainer do? Are inverted loops or other manuevers generally off-limits? By the way thanks for the TT pro 46 recommendation. It ran great straight out of the box. Smooth transition and easy start-up. It ran better new out of the box than my Tower 46 did after over a gallon of fuel. Thanks!!!



QUE TE VUELE BIEN!!!

Wanna know?

It can't do 3D stunts definitely. Usually trainers don't do spins well.

The 3D stunts thing is a definitely no-no thing, but other than that trainers can usually do any other stunt. [8D]

Un Salu2!

Trainers are aerobatcially challenged for a number of reasons:
1. Control surfaces are smaller (with less throw) - makes aerobatics slower.
2. Wings have dihedral, washout, and are often flat-bottomed - makes inverted flight far more aerodynamically difficult because a lot of elevator is required to maintain it, and also, because of the washout and wing-shape, the stall speed inverted is often much higher than right-way-up.

Given that most aerobatic manouvers require consistency and smoothness, it is always going to be more difficult to perform the manouvers with a trainer wich is VERY biased toward flying right-side-up. Further, many manouvers require the plane to maintain knife-edge travel which requires a large rudder. Things like slow rolls, 4 point rolls, etc all require Knife-edge capabilities. Many trainers simply do not have the rudder "authority" to do them.

Finally, aerobatic planes have a very good seperation between the pitch, yaw, and roll axi. The rudder affects yaw only. The elevator affects pitch only, and the ailerons affect roll only. Trainers have dihedral wings, and the controls often affect more than one axis (rudder affects yaw and roll axis on a trainer). Thus, to perform aerobatics, you have to reverse the "unwanted" axis rotations.... for example, in a hammer-head, you have to use throttle, rudder, and opposite aileron to get a straight hammer-head with a trainer, but with a more aerobatic plane, you could do it with pretty much rudder and throttle only.

So, some moves are simply not possible with a trainer because the control surfaces do not have enought authority (like a knife-edge), and other moves are more complicated by having to counter-act the adverse axis change with the trainer-s control surfaces.

Bottom line, there is a lot a trainer CAN do, and if you can do the moves with a trainer, you can be pretty confident that you will be able to master them on a an arerobatic plane as well (aerobatics becomes easier with an aerobatic plane!).

gus

The knife edge thing is about impossible, but most other manuevers are. They may require adding more throw to the control surfaces, and they might not be pretty, but they're possible.

The only things you really need to worry about, and it's true of most planes, is yanking hard "up" from a high speed dive or full throttle loop.
Dennis-

THE ONLY THING THE AVISTAR CAN'T DO IS CLIME IN KNIFE EDGE. IF ITS SET UP RIGHT IT WILL DO 3D. IT WILL DO A NOT TO BAD LOOKING WATER FALL THE OTHER TRAINERS I DON'T KNOW ABOUT

You can do anything with it that you try. It may not do them all perfect, but you can try. Add more throw, and if you have the power, it will be fun. Be carefull with the high G pullouts. You may fold a wing if it is not strong.

I have a PT-19 giant scale that is supposed to be like a trainer, and it will do some of the 3D stuff better than my G-202. Pinwheels like nothing I have ever flown.

IF you really arnt comfortable going to a low wing plane yet, try a midest aerobat trainer. It is an aerobatic trainer ARF. A couple guys at my field have these with a os.50 SX with a tuned pipe. they takeoff in about 3 feet and have un limited vertical. These guys are nuts though, they try to see who can go the lowest inverted and end up landing upside down. very funny. Only thing that broke last wekend on an inverted landing was the prop! But your trainer should do some good basic aerbatics. On your control surfaces, move the linkage to the hole closest the surface, this will give you more throw. Also on you servo arms, move the linkage to the outer most hole (all except throttle) and you will get even more throw. I did this with my PT-40 trainer (may it rest in pieces) and it could d some pretty insane snap rolls and good outside loops, square loops, tailslide were my fav. when i was forst learning. I also opened up my servo tray hole in my wing and added another servo so on my computer radio i could have flaps, also flap and elevator coupled. On a good no wind day i could have it at a fast walking speed about 3' from the deck with flaps down. good luck!

sean

This some thing that you can try but watch what you are doing !! You can move the CG 1/4 in. forward and the plane will respond faster. Or balance where it is level with tank emty, this works on the Lt40 I fly for fun.

Btw, I've seen several trainers that wouldn't spin upright, but many of them spin inverted quite nicely. The reason is that the flat-bottom wing is easier to stall upside down than rightside up.

Didn't see what kind of trainer you're flying -

The only real limitation on what you can / should try is really wing strength. Given that it's properly built and doesn't have hidden damage, most anything that starts from from level flight (upright or inverted) should be fine. I *would* stay away from full-power dives followed by hard pullups though.

If it's a flat -bottom wing it'll respond well to reducing the wing incidence by putting a shim under the trailing edge. For an LT-40, 3/8" isn't excessive. You should find then that you need to adjust the elevator trim a bit, but it should be much nicer in the air.

Rick

The way I understand it, its not the stunts themselves as much as it is the force exerted on the surfaces of the aircraft. In other words no SNAPS of the elevators and such.

Tom
Pearl Harbor, HI

No terminators, blinders, or heart attacks!

Yo soy un "Newbie"

LOL!

Una "Newbie" con 520 postes?

No mierd...

never mind

My trainer could scramble an egg, but darned if I could get it to clean up after itself.

Kerry

I wish I could get my trainer to watch the kids....

Andy

One of the reasons some trainers won't sping for beans upright is they have "Washout" n the wings. The wings are purposefully bent so that the wingtips stall later than the wing root. That makes it very difficult to get the plane to spin upright, but inverted spins are easier.

The flat bottom wing really isn't the reason for the spin being difficult.
*****

You can help prevent the overspeed condition which leads to the wing folding. Use a longer lower pitch propeller. Most people THINK you have to use a 10X6 on a .40 size trainer. Try a 11X5 or 11X4 or if ground clearance allws... 12.25X3.75. It will seem like a whole new airplane. Almost all aerobatics will be improved. Most .46 powered (.40 size) trainers can climb straight up out of sight (if you let it) using the 12.25X3.75. The longer lower pitch propellor will act as an airbrake in dives. It will also help you slow down for smoother landings.
***

What a trainer can't do? It can't do the maneuvers as CLEANLY as a plane designed for them. I've seen .40 class trainers do just about any maneuver you can name. One of my favorite things to do with a Dynaflite Butterfly (99 inch span .15 powered) is laps around the traffic pattern inverted. (it is NOT easy but it is possible.)