anyone found a way to tune dd tail?

[pmbou]

I slapped a dd tail with slim tail blade on my cp pro (otherwise it's stock).
When I climb, nose goes left (not enough tail power).
When I descend, nose goes right (too much tail power).

This issue seems common, I have read about it before. I know that the 3-in-1 has enough power to hold during a climb, because I can compensate manually by pushing right on the yaw stick as I climb.

It's not a matter of tuning the proportional control either. If you imagine that the elevator and rudder are linked by the 3-in-1 with a line, where x is elevator and y is tail power, it's like the proportional control only shifts the line up and down by a constant, to move the intercept, but doesn't change the slope. So the best you can do is get the bird to hold for any one given thrust setting. Sorry if it's confusing when written like that! Chart is below.


The gain setting only seems to affect how loose or tightly the tail is tied into the gyro. It's not the right way to go about a fix for this.

It's like the slope of the tail gain is too low. When up is pushed, not enough power to tail, when down is pushed, too much.

I assume that changing the tail prop size, pitch, or motor won't help much either, that they're akin to turning the proportional adjustment.

So, has anyone figured out a way to improve this, maybe to hack into the 3-in-1 and monkey with this? Is there another way or am I missing something? I prefer to tune the system better rather than slap on another control system like hh gyro or programmable radio.

:dontknow

[zooland1]

What motor do you have and what prop? I'm using a GWS 50 motor with 3x2 push on prop and have no problem at all. Maybe you just got a bad motor.

[txflyer]

the hh gyro is a must have. it helps alot esp since youve already got a dd motor. i used a 3020 press on prop, my tail motor never got hot. maybe warm at best.
i know that when i punch the throttle i get a nice little kick. not much tho. learn to counter it. i installed the wireing and esc for my bl dd tail. so i hope maybe thats got enough now to hold the tail better.

[Buzzkill]

Tx, Use digital mode on the gyro with the BL tail. helps hold better, quicker response.

[txflyer]

wont that kill my servos faster ?

[Buzzkill]

It shouldnt affect your sevos. It will only affect the gyro and the tail motor.

[txflyer]

ya thats what i was just thinking about. did you use digital mode on something besides the tail ?

[Buzzkill]

Nope, I dont think there is any digital mode on anything besides the tail.

[pmbou]

The tail prop is GWS gw/h001-fd5002-030b, stamped EP-4530, not sure about the tail motor, other than it came from cookeville raceway & hobiies in TN. I can ask the guy I bought it from. He sold it as a dd tail for blade cp pro. At the time, I thought there was just one kit. But it seems that there are a number of different motors in the same size that all look alike. Mine is not stamped with any identification other than what appears to be a mfg date of "('04-11-2.)" The end bell housing is grey plastic.

[txflyer]

i used the gws edp 50xc motor. it didnt crap out untill i started flying a 1500mah 3s pack..

[zooland1]

I'm going on a year and a half now with the same motor. I use anywhere from 1100's to 2100's. Make sure you do a water break in first. Makes a huge difference in brushed motors.

[txflyer]

ya i didnt do a break in when i got it. doesnt matter now monday afternoon the bl tail motor will be installed, esc programmed and back in the air i will go.

[pmbou]

How can you do a water break-in on these little sealed motors? I just did a dry break in with 1.5 volts for 5 minutes... figured it's better than nothing.

[txflyer]

i think its the same way you did the dry break in but you just submerge it in a glass of water.

[Gino CP]

For an effective DD tail:

GWS CN12-RXC motor (Examples: EDP-50XC, EDF40H)
GWS EP-0320 prop (press on. BUt you can bore out to 2mm and use a 2mm prop adaptor)
M1.6 machine screws x 2pcs
G90 or Telebee 6g HH Gyro (Gyro sense disconnected)

No revo mix on the DX7. Trims and subtrims all set to zero. Gyro is between 5 and 6 o'clock on the manual gain control. BUt I will fine tune this because I get stepped left turns on windy days. Could be the limitation of a motor tail though.

Videos to show tail:

Hold with punches

http://www.youtube.com/watch?v=DPG5j34KHRw

Control

http://www.youtube.com/watch?v=ix7hpKEVxtg

[pmbou]

Gino, yours is even simpler than my setup.
I have the 2mm adapter, which uses two tiny set screws that are no fun ot work with. I will be buying some 3020 props in the near future for sure.
Do you know of a good place to get them?

I also have a futaba gy240 hh gyro that I haven't installed yet... was saving it until I stop crashing every other flight. Right now I am learning a lot by pushing my limits...

Thanks for info

[Gino CP]

I'm from Manila, so I get my parts from Hong Kong (www.heli-fever.com). If you get other stuff from them, the Speedpost shipping fee doesn't seem much ata all.

[pmbou]

For the dd tail, I got my hands on some 3020s. Previously I was using 4530s. My impression is there's not much difference. The biggest advantage of the 3020 appears to be the simplicity of putting this prop right on the motor shaft, rather than using an adaptor with set screws like the 4530. Next biggest is dirt cheap price ($1 or less).

There is a different sound - higher pitch. Also, the gain setting that works best for the 4530 is a bit too high for the 3020 - it tends to wag a little. The proportional setting was the biggest surprise - it stayed exactly the same! This little prop must be spinning a lot faster. It should be drawing the same total power either way, since it's countering the same torque and behaves the same. I would guess that motor will wear out a little faster, but maybe not (I suppose it could be drawing a lower current that's actually easier on the brushes and commutator). Time will tell.

[txflyer]

i loved my dd gws motor with the 3020 prp. the tail held good. unless i punched it id get 6 to 8 inches of of kick.

[eddo22]

i loved my dd gws motor with the 3020 prp. the tail held good. unless i punched it id get 6 to 8 inches of of kick.

i was seeing this too after i went to bl main motor. added the gws ics 50j esc to the tail and now it's gone! :mrgreen:

[txflyer]

i will keep that in mind incase for some odd reason bl tail goes out.

[eddo22]

oh, you went brushless tail...didn't know that hehe.

[txflyer]

yup after having a tail motor go out mid flight, i wanted something i could not worry about..

[eddo22]

nice...what are you using for your tail exactly? i told myself i was done with the u/g's on this but maybe not...hehe. thanks,
ed

[pmbou]

I have not yet installed the BL tail motor and electrifly BL-8 ESC that I bought (they came in a mixed bag of used parts that I bought). The ESC can be programmed to one of 4 different RPM settings. Maybe this will allow me to effectively change the slope of that line and avoid kickout. Otherwise, I can install my hh gyro. I was avoiding installing extra stuff though.

So far I am using the GWS brushed motor and 4530 or 3020 tails and it works good, is reliable, simple, light, but the tail just isn't tuned perfectly with the throttle.

The best solution is probably to invest in a decent radio and use that to program the throttle/tail rotor mixing curve. Any suggestions for a good radio that is capable of this, reasonably priced <$250?