Noobie Question - Tail Kicking

[pittsjock]

Greetings Gents:

I have made a few unplanned modifications to the heli, but getting better at flying my R30V2. I was up for a few tanks today and had a great set of flights.:thumbup:

Last week wasn't so good. After reading a bunch of posts, I figured out that my engine was lean. In the process of getting it tuned correctly, I managed to crash the heli. Not too much damage, but she ain't showroom new anymore. Anyway, I repaired the damage and took her out today. With the TT engine high speed needle set about 3 turns out, she ran nice and cool - could touch the rear engine case after sustained idle and not burn yourself. I couldn't leave my finger there forever - it was hot enough to be uncomfortable, but not to burn you. I am guessing this is about right?

My only problem is that the tail is now not holding as well as it did previously. If I hit the throttle hard, the tail kicks right about 45 to 60 degrees and then catches. It was pretty windy today, so not sure if this had any impact. From reading other posts - I am thinking this is a headspeed issue? Keep in mind that I am still working on hovering and very limited FF.

Thanks for any help.

Pittsjock

[vandelescrow]

what gyro are you using and what do you have the gain set to?

[pittsjock]

what gyro are you using and what do you have the gain set to?
Futaba 401/9254 and the gain is set to 90 Up and Down per RaptorTechnique.

Pittsjock

[Raptorman37]

low headspeed is a possibility, you didnt put any Revo mixing in did you? Also check your belt tension, if its loose the sudden increase in power can cause the belt to slip on the pulley until the speed stabilizes. check your linkages, make sure they are smooth and free running

[pittsjock]

Thanks RaptorMan. I have flown several tanks since this post and things are better. I changed to 30% nitro (from 15%) and retuned the motor - running cool and smoothly. Also, I dropped the gain to 85% on the gyro. Overall, the tail is holding pretty well. Everything is pretty smooth and the tail is tracking nicely in all the situations I am putting the heli in.

I am thinking of experimenting a little with the throttle curves to increase the headspeed. I don't have a tach or a thermometer/heat sensor for the motors, so I expect I will spend a few more dollars before I get too much further down this road.

Regards, Pittsjock

[Raptorman37]

what is your hover pitch? mine is at 5.5 in all conditions.

[vandelescrow]

You said your gain is set to 90. I'd recomend moving the ball link on the servo horn further out, resetting the end points on the gyro so it will not bind, and this will let you lower the gain. I was informed by Waynne Mann a 90 gain is way to high. In heading hold it should be in the 60's.

Another thing that has been mentioned in these forums, and I had my new R90 set up this way was have the ball link so far in on the servo horn that you are getting almost full revelution on the servo before the tail binds. Waynne test flew my heli and said this is totaly wrong, you will burn up your tail servo this way.

My R90, before Waynne looked at it, it was around 95 gain and I was unable to get it to hunt even at 100 gain. After making the above changes it is now at 68.

P.S. I'm using the Futaba 611 gyro.

[Raptorman37]

Burn up my servo?!:shock: ill try what you said and see what happens:thumbup:

[pittsjock]

You said your gain is set to 90. I'd recomend moving the ball link on the servo horn further out, resetting the end points on the gyro so it will not bind, and this will let you lower the gain. I was informed by Waynne Mann a 90 gain is way to high. In heading hold it should be in the 60's.
.


I am using a Futaba 7CHP radio. As I understand it, the gyro setting begins at 50% and ends at 100% - below 50% is effectively off. So, a 75% on my radio equates to a gain of 50%. I now have it set to 80%, which I believe should be around 60%. It is holding the tail pretty well, although I played around with idle up this weekend and was getting a little kick out if I really hit the collective hard. I am not sure I have my engined tuned correctly - I had everything working great - no kickout, but the engine felt like it was getting hot. Once I enrichened the mixture, the tail starting kicking out again. I ordered a temp sensor today, so the guesswork will be over soon enough.

Regards, Pittsjock

[vandelescrow]

What I understand JR 0-50 is rate mode 50-100 is heading hold, Futaba uses negative numbers for rate and possitive number for heading hold. I don't use Futaba transmitters so I may be totaly off.

For heading hold, you should set your gain as high as possible so it does not hunt. If the gain is real high, is is probably due to slop in your tail system. From reading articles in magazines, it seams the biggest test for the holding power of your tail is backwards flight.

One thing that was found on my R90 that was causing tail holding problems was I had a gyro strap on it (a velcro strap to keep the gyro in place if the gyro tape gave loose). It was introducing vibration to the gyro. These straps are a good Idea but I found they should be a bit loose so the gyro tape can do it's job and insulate the gyro from vibration. I had my strap so tight it was putting the vibrations back in.

P.S. yes a poorly running engine can cause the tail to kick out, same with a too low a head speed