Steering rate for oval racing

[robbo1]

Hey guys. Question to all, in particular guys who race oval cats. I do not race (I would love to) as there is not any fe clubs in my state, so I just oval bash.

Is there a general rule of how much steering rate to dial into the rudder for turning on the oval course? I read somewhere here it may have been 20 degrees but can not seem to find it.

[jaike5]

The faster you go the less steering rate you need. What size cat , motor, prop, and voltage would help.

[Mike W]

My preference is to have just enough steering to cut a perfect turn tight on the buoys, and with as close to 100% EPA and rate as possible to maintain servo torque and resolution. Mechanically I start with the innermost hole on the servo arm and end up quite close. I see most other using the outermost holes and dialing travel way back.

Some will argue they need more but my preference is to nail every turn if I can stay on the buoys and this helps me to do so with repeatability regardless of the hull type.

https://www.youtube.com/watch?v=ia5Uoo7p1OI

[T.S.Davis]

I've wondered if it's better or worse for a servo to let it use more of it's throw. Like Mike said, we can dial throw out with end point adjustments but is that better or worse than a natural limit so to speak? I honestly don't know.

Next summer I plan to fiddle with some expo on the steering. Some of the car guys do this. My thinking is to sort of fuzzy up the middle bit of steering so it's less responsive going straight and then as you turn harder it responds accordingly. Having the servo use more of it's throw would seem better for that. At least in my head.

[robbo1]

The faster you go the less steering rate you need. What size cat , motor, prop, and voltage would help.

It is a apparition 32 inch I think. 1600kv motor on 6s running cnc alloy x442 at the moment until I get it dialled in then throw a x642 s&b.

Ride pads have been blueprinted flat. Offset upgraded dual pick up genesis rudder with offset bracket.

I know they are not a great turning boat because of narrow hull.

[Fluid]

I’ve used exponential on several boats, mostly SAW boats but a couple oval racers which were a bit sensitive to rudder input. That makes them easier to drive without spinning out, but also allows for sharp turning at low speeds. You’d have to experiment with the amount of exponential, IIRC I used around 60%...


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[robbo1]

I’ve used exponential on several boats, mostly SAW boats but a couple oval racers which were a bit sensitive to rudder input. That makes them easier to drive without spinning out, but also allows for sharp turning at low speeds. You’d have to experiment with the amount of exponential, IIRC I used around 60%...


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Sorry for my ignorance fluid, but what is exponential and is it set through the transmitter? Is that the same as steering rate (D/R on my transmitter)or is it the steering curve?.... would like to experiment.

[T.S.Davis]

It is a apparition 32 inch I think. 1600kv motor on 6s running cnc alloy x442 at the moment until I get it dialled in then throw a x642 s&b.

That will be a really tough setup to oval race with.

[Shooter]

Nice vid Mike. That thing is really carving it up. I don't know much about monos, but it looks like the nose is digging in nicely and you have control of the hooking. I'll never forget the time I added expo to my P-40 warhawk airplane (less response close to center, and full response at the limits). Eeeeek. If you overdo it like I did, your model will feel lethargic and slow to respond.

[Fluid]

...what is exponential and is it set through the transmitter? Is that the same as steering rate (D/R on my transmitter) or is it the steering curve?.... would like to experiment.

Exponential is set through the transmitter, and effectively lessens the servo movement near neutral but allows full movement at the ends of servo travel. Not the same as dual rate or end point adjustment.


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[robbo1]

Ok found exponential (under steering curve on transmitter)… it is set on default 0 percent, with the curve going from one corner to the other in pretty much a straight line. Anything from positive 14 percent onwards or negative 14 makes the servo start twitching back and forth, with noticeable movement at the rudder blade. I guess it is just a matter of testing and adjusting the dual rate if need be until I feel comfortable with the turning radius at the max speed the boat can handle. Thanks to all the replies.

[robbo1]

Update on rudder throw.... went to the lake this morning. EPA and EXPONENTIAL set at default settings (EPA at 100 percent and EXPONENTIAL at 0 percent; always been at default have never adjusted). D/R adjusted to 65percent which gave me 20 degrees of rudder movement to the left and 20 degrees to the right. Very happy with that adjustment… Found I could carry more speed into the bend and through it, without having to over correct and running the risk of flipping or loosing too much speed.