EXI 450 & Esky 0704B gyro HELP!

Guys,

Here's what's happening. I have the tail setup for no rotation in rate mode, 0 subtrim and no stick trim. When I switch to HH mode the 450 rotates CW at a fairly slow rate. At this point I can put about 5 clicks of CCW rudder stick trim in and it neutralizes the CW rotation. Then when I switch back to Rate, you guessed it, now I have to take the rudder stick trim back out.

I have a real short servo arm 8mm, and the arm on the servo is at 90 deg. in the stable Rate hover. I have both the gain and delay on the 0704B set to full +.

At this point I'm starting to question the effectiveness of the 0704B as it seems that it isn't any more locked in, in HH mode than it is in Rate.

Give me some ideas guys, I'm about out of things I can think of to try. From what I understand once you get a good hover in rate when you switch to HH you should only have to adjust the gain on the DX6i to get rid of any tail wag you might have.

??? ??? What am I missing?

I'm getting real close to putting the 0704B on the shelf and getting a better gyro $$ to try and put these tail issues behind me.

In what gain gyro is set? Maybe gain is too low? For me esky gyro holds almost perfectly

P3tras,

I have varied the gain from 50% - 70% on the DX6i for the gyro. I do see some wag when I get up around 70%. So I believe the gain is changing to the gyro when I adjust it at the TX.

Keep the ideas coming!

I'm wondering if the 0704B has been damaged in a crash. The heli doesn't seem to have any unusual vibrations. I'm not sure if trying to isolate the gyro from the tail block, to try and eliminate any extra vibration, would have any effect. How do you have yours mounted to the heli? Double sticky foam tape here.

Make sure the dails on the Gyro are at max, otherwise it'll interfere with adjustments made through the Tx. Also put rate mode at something like 30 and HH mode to 75, thats what mine is set on in my DX6i and it holds fine. Another question I had is why would you be using rate mode still?

I have questions about how well the 0704B is holding in HH. I went back to rate to make sure that my tail setup was correct. I set the heli for no tail rotation in rate then switched to HH expecting that the tail would hold without any input to the rudder. I find that when I switch to HH I have to add rudder trim to keep the tail holding, 5 clicks or so. I don't think I should have to rezero the tail when switching between rate and HH. Is this true? Or, should I just adjust the tail for a solid hold in HH and just keep the heli in that mode?

Thanks for all the input!

I think you should adjust it for HH mode and leave it there, rate mode sucks, lol

What you are describing here is normal operation for cheap gyros.

If the tail starts to drift when you switch to HH mode, then that is caused by the servo "creep" which is the fault of the gyro.

To fix this you have to use subtrim. And since you original TX does not have separate subtrims for Rate and HH mode then you have to use the single trim it has. Problem is you fix one thing and break the other. There is no way around this unless you get something like DX6i transmitter where you can trim both modes.

If you manually trimmed in Rate mode by moving the tail servo then you need you know about one big problem. If you move the rudder stick to the Max right you will cause slider to bind and tail servo buzz. This is a problem with limits and again back to limitation of stock TX.

I personally think you should not even use Rate mode with with stock radio setup.

Just use HH mode. Set the Slider in the dead center this way you will never get any binding.

You will still need to use trim to stop the creep and need to do that every time you fly as the out side temperature changes.

I say this from own experience with the same gyro on my belt CP v2.

P.S. Nuttcaze thx for sig!

No problem, I like the signatures because it makes things a bit more personal and its a heck of alot easier to see who is posting. I just wish more people would ask for them as I have to guess sometimes as what to make for people.

and if anyone wants theirs changed just ask, it only takes a min or two to make them up.

I am using a DX6i transmitter and have been trying to get the settings correct for both modes, rate & HH. I think I'm going to forget about rate and concentrate on getting a good solid hover with HH. Your comment about inexpensive gyros I'm going to have to agree with. With some things in life you get what you pay for. I think a better gyro will make flying more consistent and then I won't have to wonder if it was my flying that is causing the heli to freak out or the hardware. I guess I'm going to have to do some more damage to the plastic money and upgrade the gyro.

This discussion has been very helpful and it is one of the many reasons I'm thankful for this forum. I haven't run across any experienced heli pilot here in Savannah, and sometimes it would be nice to have someone to take a look at the heli and say "well here's your problem". You guys give it your all with your attempt at assistance, it is much appreciated.

Nuttcaze wrote:

No problem, I like the signatures because it makes things a bit more personal and its a heck of alot easier to see who is posting. I just wish more people would ask for them as I have to guess sometimes as what to make for people.

and if anyone wants theirs changed just ask, it only takes a min or two to make them up.

I'm gonna get a new camera and learn to post pics hopefully in the next couple of weeks and I'll fet a better pic of my E and you can change my sig then.

Donnie D

cgetman02:

Check this video out from Bob at helifreak.com , you will need to register to view it. Here he talks about how to setup for HH mode and the "creep" issue. Funny how he says no creep what's so ever and then he sees it, lol. Gotta see.
http://video.helifreak.com/?subpath=finless/hdx300&filename=tail_gyro.wmv

I have not seen any videos for Rate mode setup.

Since you have programmable radio I think you should be able to setup up the esky gyro no problem. Once setup properly its not a bad gyro and does hold the tail great in sideways wind gusts as I checked myself.

I do want to tell you my experience with the gyro pots or dials. There are two pots, the limit and the delay. If the limit is turned up to high you will notice tail going faster in one direction than the other. If I turn delay to max, I get servo switching while its on the ground. When I move the rudder stick, the servo over shoots and then jumps back by it itself. Acts kinda crazy. This will cause havoc in the air.

Before you deal with Rate or Head hold modes you first must deal with the Limit to not kill the servo or wear out the tail.

The limit pot is to limit how far the tail slider can move from where its at. Its there to stop binding when slider moves to far and hits the casing. Put gyro in Rate mode (light off) then move rudder stick one way to max and turn up the pot while holding rudder and you will see slider move back some. Thing is it only limits to few millimetes. Maybe you can try limits in DX6i and let me know if can limit even more.

I tried to manually trim (slide servo on boom) for Rate mode, with limit at max on gyro, slider still binds when I push rudder stick all the way to the right. Because of this I think you can not even setup for Rate mode with original radio without binding. Now with DX6i you might be able to add lots more limit for Right stick movement. I only have stock radio.

"Rate Mode"
Let's say you center the slider in the middle of the tail shaft. When in Rate mode, the servo centers or goes to 90 degrees with trims centered. Obviously this is not where it needs to be to hold tail as your heli spinning out of control counter clockwise. You need to counter act the force from main blades by adding lots of Right trim. On stock radio that's not enough so must manually trim but then the binding issue. Check if DX6i has subtrim just for rate mode and trim it there. You can not use main trim that affects both Modes because for HH mode you don't want any trim at all except to stop the creep.

"Head Hold"
Easiest to setup. You just center the slider. Trims at zero, initialize, then check for creep, trim it out and off you go. Creep is affect by changes in temperature so you need to always look for it at least with this esky gyro. One last thing you adjust is the gain but you only do it once and leave at that.


I know few guys here recommend the Telebee gyro. I have found it here the cheapest but shipping is around 2 weeks.
29.99 + 4.79 = 34.78 You get this price when registered.
http://www.hobbyking.com/hobbycity/store/uh_viewItem.asp?idProduct=8471
Its cheaper than esky but everyone seems to say good things about it.

I hope you can follow my writing and if something not clear just ask. I will try my best to share what I know.

Just re read the first post.

From own testing, I could not max out all the pots on the gyro as that caused different rotation speeds and servo jumping. It would turn very slow with Right rudder. With slider perfectly center I only had to add very little of limit maybe to 9 o'clock position. The delay I have it set at little less than half or 12 o'clock. I do use stock radio so your mileage might vary.

I still don't know exactly what the Delay pot is for but I think its for speed adjustment for different servos. It say something about that in the manual.

flagmax wrote:

I still don't know exactly what the Delay pot is for but I think its for speed adjustment for different servos. It say something about that in the manual.

Delay
This delay is the fast Gyro correction signal to the non-digital servo if it tends to regulating oscillation.

i have read when you use digital servos you set the delay to 0.

I'll carefully read the above information and hopefully I will be able to cure my wayward heli. The weather here in Savannah is good for ducks today. Maybe tomorrow I'll be able to do some testing.

Thanks you guys you're the greatest!

After fiddling with about everything trying to get my wayward 450 to act right, I swapped gyros with the 450 that was acting right. Guess what, still had the problem! After much head scratching and changing out the tail slider/blades (ground to tail collision), I noticed that the belt looked the slightest bit loose. Tightened the belt and what do you know, now I have some control! I guess the belt was slipping? Anyway, I'm back in the air with more control with the problem heli. The symptom I was seeing was that I couldn't get the gyro to lock in, in HH mode. Around 70 gain on the DX6i I would get a quick tail wag and as I lowered the gain I wouldn't get to a steady hold. The heli would go into the slow wide wag of low gain. There was no sweet spot between fast wag and slow wag. Check those belts on those wayward helis!

I'm going to take Nutt's suggestion and get my helis flying in HH and not be concerned with rate mode. Thanks for everyones help on this problem. I learned a lot, and I hope others have been able to use the information also.

Y'all are the bee's knees!