JAE 21 FE Oversteer

[Peter Gise]

My JAE 21 FE tends to "oversteer" when exiting turns. Would moving the turn fin (forward?) a bit help to make it steer more neutral?

 

[HOTWATER]

Move it back...moving it forward will only make it worse...

...also, try to dial some more steering out..

-Kent

 

[Peter Gise]

Thanks..I'll try both suggestions. I'm new at riggers and I'm not used to the quick turning!

Pete

 

[Mike Larson]

When you say dial the steering out..... are you reducing the dual rate, or, just the actual endpoints?.... thanks mike

 

[HOTWATER]

From what Pete is explaining it sounds like he is close...dual rate adjustment should work out for him.

-Kent

 

[Mike Larson]

Not meaning to jump Pete's inquiry, i've encountered the problem on one in my fleet and dont like the idea/characteristics the hull handles, and look to remedy is all.... dual rate first, it looks like.... thanks mike

 

[Peter Gise]

This hull is very sensitive to rudder motion and turn fin position, shape & etc.!

I'm going to try a couple of things on my MT-4 Tx steering (this Tx is new to me and it behaves a lot different than my older, simpler MX-Sport).

On the MT-4 I can change the steering rate (using dual-rate) but it also has a function called "curves" where you can move the point that the rate changes along the steering curve on-the-fly (I programmed the curves function into the AUX CH dial). I could make the steering less sensitive towards maximum deflection of the rudder, so it wouldn't turn as hard at the exit of the turn.

 

[Blackout]

Probably good to make sure your servo arm is short and your rudder arm is long. That way you are close before making your adjustments at the radio.

 

[Peter Gise]

Good idea...thanks!

Pete

 

[Chilli]

On the MT-4 I can change the steering rate (using dual-rate) but it also has a function called "curves" where you can move the point that the rate changes along the steering curve on-the-fly (I programmed the curves function into the AUX CH dial). I could make the steering less sensitive towards maximum deflection of the rudder, so it wouldn't turn as hard at the exit of the turn.

AKA "Exponential" on Futaba radios though I don't think you can't do it on the fly with the 3PM. Dial down your end point adjustement first and then fine tune your steering curve.

 

[Don Ferrette]

How strong is your steering servo? Is it new? What voltage? A hydro that struggles to "unsteer" itself once it's "hooked up" on the turn fin can also be caused by a weak, underpowered or failing steering servo. I use a Futaba 9405 hi torque servo in my JAE 21 FE, it turns and "unturns" on a dime.

 

[HOTWATER]

All good advice here....

-Kent

 

[John Finch]

How strong is your steering servo? Is it new? What voltage? A hydro that struggles to "unsteer" itself once it's "hooked up" on the turn fin can also be caused by a weak, underpowered or failing steering servo. I use a Futaba 9405 hi torque servo in my JAE 21 FE, it turns and "unturns" on a dime.

I agree with Don. Most times it is a weak servo with not enough power to come back to center that causes this particular problem. Hydros, monos, all boats. The prop is trying to put the boat into a right hand turn, so straightening the boat after allready in a turn takes more power than putting the boat into a turn.

 

[Terry Keeley]

Also run a 5 cell (6v) pack and be sure your linkage is stout. I use 1/8th ss welding rod for rudder pushrods on everything, thread the ends 6-32 and use ball links on each end. -_-

 

[Peter Gise]

How strong is your steering servo? Is it new? What voltage? A hydro that struggles to "unsteer" itself once it's "hooked up" on the turn fin can also be caused by a weak, underpowered or failing steering servo. I use a Futaba 9405 hi torque servo in my JAE 21 FE, it turns and "unturns" on a dime.

The servo is a new 2056 Traxxas waterproof servo that came with the hardware kit. I'm using the BEC on the ESC so I assume it's 5v, but I don't know how much current it can supply (servo plus receiver). The linkage is 4-40 and very short (maybe 3 inches); but it pushes on the rudder arm for right turns. However, I don't think it's flexing as it's very stiff.

Maybe this servo isn't strong enough?

Pete

Update: The ESC/BEC can supply 3.5A at 5.0V so it should have the current drive.

 

[HOTWATER]

If you are using the UL-1 Esc/motor combo, you do not need a seperate rx battery.

Don has a good point about the servo possibly not being strong enough (good advice from Mr. Finch as well)...the servo might just be the weak link there. Don is top notch with riggers so I would definately try a stonger servo...who knows, you may be surprised!

-Kent

 

[Blackout]

No torque specs on that servo on Tower's website. Could be a weak servo for sure.... Step up to a metal gear servo too.

 

[HOTWATER]

Yep!

 

[Brian Sorgente]

How strong is your steering servo? Is it new? What voltage? A hydro that struggles to "unsteer" itself once it's "hooked up" on the turn fin can also be caused by a weak, underpowered or failing steering servo. I use a Futaba 9405 hi torque servo in my JAE 21 FE, it turns and "unturns" on a dime.

The servo is a new 2056 Traxxas waterproof servo that came with the hardware kit. I'm using the BEC on the ESC so I assume it's 5v, but I don't know how much current it can supply (servo plus receiver). The linkage is 4-40 and very short (maybe 3 inches); but it pushes on the rudder arm for right turns. However, I don't think it's flexing as it's very stiff.

Maybe this servo isn't strong enough?

Pete

Update: The ESC/BEC can supply 3.5A at 5.0V so it should have the current drive.

I just googled the servo and found these specs:

http://www.servodatabase.com/servo/traxxas/2056

Unfortunately they dont show what it does at 4.8 volts. At 6.0 volts it has plenty of torque to turn the boat though. It might be worth trying a 6 volt receiver pack just for grins if you can fit it in the boat. Its hard to say how much torque your going to lose dropping the voltage 1 volt.

Check all of your radio settings, try turning the rudder while resisting its throw with your hands and see what it does.

 

[Peter Gise]

I'm going to try a stronger servo...Futaba 9405 at 100 oz-in versus the original Traxxas at 80 oz-in. The BEC provides 5.0V at 3.5A so that should be enough drive current.

BTW, the oversteer got worse when I went from an H-5 to a pitched-up H-6 with a significant increase in speed. When I accelerate it's difficult to keep the boat in a straight line (tends to turn right due to the turn-fin, rudder on the right, and prop torque) until it is up to speed...once up to full speed it runs true and turns like a demon...just hard to unwind it after a turn around the buoys.