Espritmodel.com Telemetry Radio
Reply
Thread Tools
Old Mar 05, 2007, 08:14 AM
Registered User
Joined Dec 2005
354 Posts
Help!
Honey Bee FP requires constant trimming of tail rotor - Why?

Hi,

I have a HBFP and have just upgraded it to run from a lipo. As a result of this I did experience tail wag, however I have since turned the gain down slightly and this has gone away. Also I did turn it down a little too much and got the large swings.

I believe that I have now found a happy medium, however what I am finding is that when I first set the heli up (after charging the lipo), I centre all trims except throttle which I set to min.

I connect the battery and let everything calibrate.

I take off and maintain a hover and adjust the tail rotor trim e.g. to the right slightly and I continue to fly making small adjustments, however after 5-10 mins I find that the adjustment is all the way to the right.

If at this point I stop and disconnect the battery and re-centre the trim and take off again it is all together possible that this time I have to trim to the left with the tail rotor.

Why would this be right one time and left another? It doesn't seem consistent and I am having a hard time getting the trim correct as it keeps changing.

I have tried changing the proportion but I am trying to leave this as is for the moment. In the past I when I have had to trim right fully I have adjusted the proportion to compensate for this and then found after re-connecting the battery that I have to ajust the proportion back the other way.

Help appreciated.

Thanks
Mark
mdavenport is offline Find More Posts by mdavenport
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 05, 2007, 08:24 AM
Idle up!
PLATINUM's Avatar
USA, VT
Joined Nov 2004
5,802 Posts
The FP from all that I have read is a squirlly little heli. I had the CP2 and to me, that was squirlly..

I think that when it comes down to it, these motor tail helis with 3-1/4-1's are much like the picooz in their trim ability. You start out and it tends to spin one way, as the power levels off it flys fine, as the battery gets low it starts to spin the other way.

So it probably is natural for this heli, unless you have flown the heck outta it and the tail motor is failing.
PLATINUM is offline Find More Posts by PLATINUM
Reply With Quote
Old Mar 05, 2007, 08:26 AM
Crash King
corwyn's Avatar
Worcester, MA, USA
Joined Nov 2006
1,689 Posts
After 5-10 minutes, there's a good chance that your LiPo is running out of energy, especially if you're running heavy (are you using training gear?). When mine starts to have trouble holding tail without a lot of rudder (I don't use the trim while I'm flying), I know it's time to recharge the battery.
corwyn is offline Find More Posts by corwyn
Reply With Quote
Old Mar 05, 2007, 08:34 AM
Registered User
Joined Dec 2005
354 Posts
Should this be happening after 5 mins though? I have the following lipo upgrade:-

http://www.heliguy.com/Extras/LiPo-C...-lipo-upgrade/

The heli flies for about 20 mins before having to give too much throttle to to keep it in the air at which point I set down to prevent over discharging.

I do have training gear on but I get the tail rotor adjustment problems even with out this.

So, are you saying that this is common flying experience and that I constantly have to adjust the trim? Should I get my heli so i require not trim rotor adjustment for the first min or two and then after that correct with the stick?

Thanks for your quick response.
Mark
mdavenport is offline Find More Posts by mdavenport
Reply With Quote
Old Mar 05, 2007, 08:42 AM
Crash King
corwyn's Avatar
Worcester, MA, USA
Joined Nov 2006
1,689 Posts
5 minutes may be a little short, but 9 is about all I used to get with my 800mAH battery with stock motors. That 1200mAH may be significantly heavier (most of them are), so despite the increased capacity, you get a slightly shorter run time. And the training gear only makes it worse, as the main motor has to work that much harder.

But if you can run for 20 minutes without having trouble keeping her in the air, then maybe that's not the problem.

But Platinum is right...these birds are hard to keep perfectly trimmed. After a while, you just get used to compensating with some rudder stick all the time; I don't even notice it anymore until it gets really bad.
corwyn is offline Find More Posts by corwyn
Reply With Quote
Old Mar 05, 2007, 09:01 AM
mem
Registered User
mem's Avatar
London, UK
Joined Nov 2005
1,516 Posts
Here is my theory for why the tail trim needs changing as the battery voltage runs down.

The power a motor produces is not exactly linear with respect to voltage, and this variance will differ between the main and tail motors.

If the voltage to power curves of the motors were identical then the power ratio would also stay the same and trim would not be required. But as the voltage drops, say 20%, the relative power produced by the motors will not both drop by exactly 20% so a trim change is necessary.

Itís actually a little more complicated then that because the battery voltage is chopped up into variable width pulses by the speed controllers to drive the motors. As the battery voltage drops, the throttle is increased to increase the pulse width to keep up the main motor thrust. But the relative thrust between the tail and main motors will vary as the voltage varies and this will need some trim change to compensate. If one of the motors is nearing the end of its life then this difference may be accentuated.
mem is offline Find More Posts by mem
Reply With Quote
Old Mar 05, 2007, 09:06 AM
Idle up!
PLATINUM's Avatar
USA, VT
Joined Nov 2004
5,802 Posts
Corwyn, I was gonna say same thing.. that battery is pretty heavy! The FP runs best on a 2 cell 700-800mah.

A 1200-1300mah 3cell weighs about 80-90g in most cases.. the 800mah 2cell weighs maybe 50-60g. That heli is designed to be flown as light as possible. I suggest you get some 600-800mah 2cell 15-20c lipos and give her another go
PLATINUM is offline Find More Posts by PLATINUM
Reply With Quote
Old Mar 05, 2007, 09:22 AM
The RED filters through
RedTalon's Avatar
Rendon, TX
Joined Feb 2007
1,948 Posts
Here is a good place to go - I've got 3 on the way myself!
RedTalon is offline Find More Posts by RedTalon
Reply With Quote
Old Mar 05, 2007, 11:23 AM
Idle up!
PLATINUM's Avatar
USA, VT
Joined Nov 2004
5,802 Posts
Those are good also Lightflight has a 900mah 2cell 10c that is only 40gs with jst! I normally convert to deans, but on the FP it isn't worth it.

http://liteflyrc.com/Batteries%20Tru...acks/8/pic.htm
PLATINUM is offline Find More Posts by PLATINUM
Reply With Quote
Old Mar 05, 2007, 12:28 PM
#include <rcstuff.h>
Redherring's Avatar
South Africa, GP, Johannesburg
Joined Jan 2006
691 Posts
Guys, for what it's worth - I had some tail issues using the stock E-sky 4-in-1. This weekend I upgraded the radio gear to an E-flite 3-in-1 and an AR6100 Rx. The tail is now very solid with rudder trim at 0. I am getting better results with the E-flite 3-in-1.

Cheers,

RH../
Redherring is offline Find More Posts by Redherring
Reply With Quote
Old Mar 05, 2007, 12:51 PM
The RED filters through
RedTalon's Avatar
Rendon, TX
Joined Feb 2007
1,948 Posts
Will that work with the Esky TX (as long as the crystal frequency is the same?) or have you made other changes?
RedTalon is offline Find More Posts by RedTalon
Reply With Quote
Old Mar 05, 2007, 01:00 PM
#include <rcstuff.h>
Redherring's Avatar
South Africa, GP, Johannesburg
Joined Jan 2006
691 Posts
I am using a seperate receiver (AR6100 Spektrum).

You'll need a seperate receiver if you are going to use the 3-in-1. If you however get the Eflite 4-in-1, you can get a crystal for cheap (also from E-flite) that is on the same channel as your Esky Tx.

Cheers, RH../
Redherring is offline Find More Posts by Redherring
Reply With Quote
Old Mar 05, 2007, 05:45 PM
Registered User
Joined Feb 2007
7 Posts
Sorry, folks, hate to thread-jack, but noticing the conversion to LiPO, will I need to change my motors to make this conversion? I already have a LiPO charger from a previous heli. I now have the HB2FP.
Thanx, and sorry again.
T-LAM-C is offline Find More Posts by T-LAM-C
Reply With Quote
Old Mar 05, 2007, 05:53 PM
#include <rcstuff.h>
Redherring's Avatar
South Africa, GP, Johannesburg
Joined Jan 2006
691 Posts
T-LAM-C,

You can use a lipo with the FP2 that comes with a NiMH batt - no changes required. I use TrueRC 900 mAh 2 cells in mine. They work great. The 800 mAh Commonsence lipos are also very popular amongst FP2 fliers.

Cheers

RH../
Redherring is offline Find More Posts by Redherring
Reply With Quote
Old Mar 05, 2007, 06:13 PM
Registered User
Joined Feb 2007
7 Posts
Redherring, thanx much! Those are the 2 I was looking at. Also I found the EFlitewiki here and just ran through it. Great stuff. I should just slow down a bit and search the forum, huh? :-)
T-LAM-C is offline Find More Posts by T-LAM-C
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Honey Bee FP Tail drift and hot motors lmnelson Micro Helis 9 Jul 16, 2007 10:58 PM
Discussion Honey Bee FP rotor head MVPRON Micro Helis 7 May 04, 2007 12:56 PM
Discussion Any one know how to make a rotor hub for a honey bee fp? slo123 Micro Helis 12 Apr 02, 2007 01:13 AM
Help! Honey Bee FP H.H. Gyro Drift w/ D.D. tail Avibitt Micro Helis 5 Mar 26, 2007 10:58 PM
Honey Bee FP 2 tail wag on right yaw hb888 Micro Helis 0 Jul 20, 2005 07:54 AM