I have a SIG 1/6 J3 Piper cub. Always have trouble taking off straight. It always veers to the left. Same with landing. I usually fly mid wings or low wings (warbird) and never had this kind of problem.

Saw another one flying a bi-plane (Waco). Same problem. But his plane is much smaller.

I'm just worried because our runway is a two lane street but with sidewalks on each side.

I know that veering to the left is normal because of the P-factor. But this one is making 90 degree turn every take offs. Compensating with rudder helps but not that much.

Is there a way to minimize the turning?

Try a little toe-in on the mains. This is usually the number one reason for mishandling take-off tracking. Too much is also detrimental though. A couple deg is usually sufficient.

Also, If your flying off pavement, you can afford to move the main wheel axle back closer to the CG. I like to be at the leading of the wing or a little bit behind it. This will make the plane easier to nose over so be prepared for it.

Another thing to look at is the height of the aircraft above the wheels. With electrics and large props, the height needs to be high to clear the prop once the tail has been raised. This especially true on grass. However, it also affects the take-off roll. If your flying off pavement you should look at trying to lower the fuse height. Sometimes raising the tail wheel strut also works but is usually very un-scale.

And lastly... You MUST use rudder. Especially on short fuse scale planes. And I say short as compared to pattern ships. The long tail helps but even then you MUST master the rudder if you want to make good tail-dragger take-offs. Rudderless take-offs with a tail dragger is completely un-realistic (Unless you have enough power get airborne from a standing start... ).

Hope this helps,
Mike

I've flown a lot of tail-draggers and it's amazing how much they vary in this respect. Post above looks good, but sometimes there just isn't much you can do.

In those cases, I think a gyro makes sense. I plan to try one on my VK Nieuport 17. Even with a lot of experience, I abort at least 5 takeoffs for every one I get, and when it does take off it's usually in a bad direction, and that's standing on the field directly behind the plane (that helps, by the way). No shame in using a gyro. A full scale pilot sits in the cockpit and feels and sees deviations much quicker than an RC pilot can detect them.

A friend who trained full scale on Piper Cubs said his biggest challenge was keeping the thing going straight down the runway.

Jim

I'd think that the full scale Planes probably have the Optimum geometry in the landing gears, and they still do it.

The alternative is to use the left stick...

Get behind any Full Scale HWTD, and watch the 'Rudder Dance' as they start the take-off roll.

Gyros are cool, but cool Pilots are better.

Come up on the throttle gently,to get a little momentum. Firewalling it is part of your problem.
Make sure your tail wheel is adjusted perfectly straight ahead, when you are taxiing.It's hard to handle a plane if it wants to go two different directions.

Agree with all said above. One more thing to check is that both main wheels are free spinning on the axels. Any amount of binding on the axel will cause the aircraft to want to turn in that direction.

I fly my Sig 16 scale Cub once a week, many flights. Must use well timed gentle nudges of right rudder to keep straight until speed builds and rudder becomes effective as tail rises. Let speed build gradually and let it lift off when ready at around 3/4 throttle, with little or no up elevator. Wheels must be aimed straight ahead or slightly toed in ( pigeon toed). Wheel axles should line up with wing leading edge. CG should be set slightly nose heavy and adjusted for best landing, etc. performance. For landings, land on main wheels until you get the feel of stalling characteristics then try flaring/3-point landings. Wheels should not be loose and wobbly on axles. Taking off and landing in cross-winds requires keeping the windward wing down and using rudder to control side sway. Watch You Tube videos on Cub flying in crosswinds. High wing designs require use of rudder with ailerons to bring the tail around during turns and to counter "adverse yaw" problems. If you are used to flying warbirds and turning/ flying with ailerons only, Cubs and similar high-wing designs require use of rudder coordinated with ailerons.

I once tried a 'solid' axle,drilled through the landing gear, and fastened solidly into the wheels. I thought it would hold the model straight on take-of..

It didn't.....
'Rudder' ,and maybe a gyro is the only answer....

Hi- A couple basic questions-- Is ur Cub a Nitro, or Electric powered?? If it's either, u want to check on engine mounting having enough right and down thrust. It may need a little more tweeking. A Cub doesn't need a lot of rudder throw, so u might take a little out of it, if it has a lot of deflection. Like Havoc mentioned, landing gear toe in will help a lot, and help tracking, and what Earl said about easing the throttle on ur takeoff run will make the plane behave a lot better. Try not to horse the plane off the ground, as Cubs fly on that great long wing. I fly the Hangar 9 Cub, 81" W/S with an OS 46FX, and I put about 2 clicks of right trim in it on the takeoff, and reset it when I'm airborne, and coordinate turns with rudder and aileron. It will help a lot getting that left hand working the rudder as much as u can.
Biplanes are another story- the smaller they are, the more the will be a handful on the ground, but rudder control, and airspeed is critical. I find that I'm using the rudder a lot more on my Aeromaster on the takeoff run, but do allow the airspeed to come up significantly before i lift off. A bipe will snap roll if the airspeed is too slow on the takeoff, so power control is the key to improving ur takeoff skills. Check all of ur control surfaces for proper alignment as well as function, and go from there. Good luck, and do keep us posted on ur progress-- Dean

Thanks for the insights.. i've flown several tail draggers, from high wings to low wings. But this plane is i think the worst. It flies reaaaally nice... just the take offs and landings.

Anyhow, i remember my FmS P51 mustang 1400 WS that used to take off like this. It had 4 blades. Then i replaced it with 2. Problem solved.

But this J3 has 2 blades. I use 12x6. So maybe changing props might help?

I've read something before but can't find it. It's about which causes the torque roll.. if it's the pitch or the diameter.

Please help.

OK, u still haven't mentioned what ur powering the Cub with- EP, or nitro?? I'm pretty sure that the higher the pitch, the more torque- the lower the pitch, more engine RPM. You might want to try a 12/5, 12/4, or go to an 11/5, 11/6. Are u in a local club, or fly where there are other pilots?? Maybe u could get one of the more experienced pilots to look ur plane over, and see if one of them can make a nice clean takeoff and landing. They might be able to spot the problem if it doesn't improve, after all of the above suggestions. Let us know what u find- Good Luck again- Dean

I'm running OS max .46 FX w/ 12x6 prop. I'll try 11x6. That's what I have in spare. I'll see if that will help.

A younger member of our Club built that kit for his Dad...Tommy regularly flies it, and if you aren't 'on top' of it, it has a mind of it's own...
I'm suggesting that you not make every event a 'take-off', rather do some high speed taxiing, not caring if it ground-loops or not..Come up on the throttle slowly, and just concentrate on going straight..if it gets away from you, chop the throttle and start over....you need to 'lean' on the rudder, rather than hold it full over.

It's a practice / learning curve..It won't always go the same way, every time, but your reactions will soon straighten every thing out.

A lot of things have to come together, but it's very satisfying when it does..You just don't do 'blast-offs' with a Cub...take it easy.

Originally Posted by epoxyearl

A younger member of our Club built that kit for his Dad...Tommy regularly flies it, and if you aren't 'on top' of it, it has a mind of it's own...
I'm suggesting that you not make every event a 'take-off', rather do some high speed taxiing, not caring if it ground-loops or not..Come up on the throttle slowly, and just concentrate on going straight..if it gets away from you, chop the throttle and start over....you need to 'lean' on the rudder, rather than hold it full over.

It's a practice / learning curve..It won't always go the same way, every time, but your reactions will soon straighten every thing out.

A lot of things have to come together, but it's very satisfying when it does..You just don't do 'blast-offs' with a Cub...take it easy.

Thanks.. at least I'm not alone in that problem. I've watched some cubs in youtube (different brands) and they seem that they don't have those kind of problems. Though most of it take off on grass and not pavement. So not sure about that too.

Watch this video....Tell me what 'changes' he makes, between the three take-off attempts.

Hint- it has something to do with 'practice'...Pay particular attention to the throttle inputs....You don't have to fight 'torque' , if there isn't any....come up slow and easy, and anticipate swerves...

He didn't change 'toe', he didn't change props, he didn't change engines......he 'worked' at it. His tailwheel needed adjusting to 'center'-it kept turning left at taxi speeds.setting that straight would help a lot.

This happens on grass,also, but it isn't as pronounced..
Keep at it.

https://www.rcgroups.com/forums/show....php?t=2643653

Several years ago after getting back into RC after seventeen years of absence, it was finally time to cover a small biplane build during RC life #1. The commissioning of the plane was noted online with several responses about memories of the plane. Each noted what a great flyer it was and how squirrelly it was on the ground.

Expecting the same, it was surprising to find the ground handling a piece of cake, one of the best mannered tail dragger I've experienced.

I wish I knew why the difference. Is it the wheels used, Williams Bro antic or perhaps because it was fitted with a Saito .30 four stroke instead of a two stroke .20?

Whatever the reason, it leaves me convicted that there must be some esoteric dynamics involved between squirrelly and docile. And... strangely what works on one may not be the formula for the next. Several have noted that increasing throttle slowly can help, and I've noted the same but on last years build of an old 1929 Travel Air 6000, a slow acceleration very often ends up in a ground loop... far better on it is o get it rolling slightly and firewall it.

I've other planes however that firewalling is asking for a ground loop. I'm thinking that an interesting test would be to suspend the plane on a rope to see what yaw issues are introduced by the engine. For example, a two stroke winding up to 12,000 with a little crank shaft imbalance, would it produce significant yaw torque that the Saito .30 doesn't?

Many years ago, we had an engineer in our local club that we all respected for his commitment. He didn't just balance a prop, he provided balance to the prop that balanced a motor... but he had the patience of Job and the keen intellect to do that kind of stuff.... stuff far beyond we average flyers.

He explained it one day, you get a feel for how much prop imbalance to leave and where to park it on the engine cycle.... oooooK. One's initial reaction is that the guy was blowing smoke.... nope..... this guy didn't blow no smoke... he was the real deal.