Using Gyros on an RC airplane - Page 31 - RC Groups
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Feb 05, 2011, 12:30 AM
Flying Shoe
theleetbeagle's Avatar
I flew my HS again tonight in moderate winds. I turned the gain way up on a 704 (blue), I thought to near max, but after looking again, somewhere around 60-75%, those ailerons sure were moving a lot, but my flight was rock steady.
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Feb 06, 2011, 01:22 PM
God is my pilot
JimTMich's Avatar
Hello everyone, I've been having a little trouble with the harrier on one of my planes, it wants to rock some. I'm still learning the harrier.

At any rate, I thought about adding a gyro in the roll axis. Vince53 lent me a HK401B. After reading the directions and reading through this thread, I still don't understand how to use it in rate only mode vs HH mode. I'm sure I only want to use it in rate mode.

Any suggestions anyone has would be great. I hope to find some free time to play with it soon. If there is a gyro that is better suited to what I'm trying to do, feel free to suggest it. I do need to be able to remotely turn it off and on remotely. I'm using a DX7

Feb 06, 2011, 02:42 PM
New Crasher
Great thread, thanks for all the hard work to produce this.

The first posts are getting old, so I was wondering if there are any new recommendations for a balanced (performance, price, drift, vibration) servo to help me learn to fly a my PZ F4U. Technology changes, I thought I should ask before I buy.

Thanks again!
Feb 06, 2011, 05:10 PM
Flying Shoe
theleetbeagle's Avatar
Originally Posted by FlyingElvis
Great thread, thanks for all the hard work to produce this.

The first posts are getting old, so I was wondering if there are any new recommendations for a balanced (performance, price, drift, vibration) servo to help me learn to fly a my PZ F4U. Technology changes, I thought I should ask before I buy.

Thanks again!
I have this on my Hawk Sky and it works wells on ailerons:

I've purchased two. One was bad. RMA'd for replacement.

This is even cheaper and is HH and rate mode (read thread for explanation) (also have free shipping and code HPZ10 for 10% off):

Both are economy-minded gyros, but they are both recommended by Melnic, the gyro-master and I've used the first one to my advantage.
Feb 07, 2011, 12:09 PM
Team Wack-a-Mole
Melnic's Avatar
I finally maidened this contraption today. I looked at it before take off and the Rx is not centering the gyro gain channels very well. In other words, what should be very little servo movement at 5% gain (5 on the travel adjust out of 100) was way more movement than it should be. Ailerons and Elevator were "OK" in rate mode, but wacky in HH mode. I flew it anyway. Going from my car to the outdoors caused the piezo gyro to drift alot so I let it sit for about 10 minutes in the cold then it kinda stabilized. I have a spare Spektrum 6100 I'm gonna throw into this and try it again.

Originally Posted by Melnic
Well, the Ambien was kicking in so it was either cutting a cubscout pinwood derby car on the scroll saw or shooting a quicky film (hmmm, getting hard to type) and posting it here on today's ventures of 3 axis plane gyros.
YES, toggling between HH to Rate and HH 3 times wil reset the trims on both the GY401B as well as the DEtrum Gy48V.

I have my gains at30% for now. Aileron gain and Elevator gain share same gain conttrold wire. Rudder is on it's own.
Feb 07, 2011, 01:20 PM
Registered User

How many servos....?

Great thread, answering many questions I have about gyros an fixed wing aircraft. I haven't read all 32 pages of this thread however so I apologize in advance if you've already covered this.

I have a GP Giant Aeromaster with 4 ailerons having individual servos, one per aileron. These are Futaba S3001's so not exactly monsters but never the less standard in size and a current draw that can spike to nearly 1 amp, I hear. Is there a max current capacity spec for gyros, for example, the Esky 704 or the Futaba GY401. Has anyone run 4 servos of std or greater torque through a single gyro? Is it just plain stupid?
If so how would you set up two gyros so they behaved exactly the same, one for each Y harness to the ailerons? Should I just wing it --and assume the response and throws don't have to be exact (just close ~2mm) as long as the direction is roughly the same for a given rotation?

I've become a believer in the virtues of the gyro on craft other than helis and I really look forward to checking out rudder and aileron gyros for this 64 powered Aeromaster. Thanks for any input.

Feb 07, 2011, 02:08 PM
Flying Shoe
theleetbeagle's Avatar
Here's my first aft-facing video. This was in 7-10mph winds, I'd say.

You can watch the ailerons move. Unfortunately, I can't tell if it's me banking or if its the gyro working...

Next flight I will purposely only use my rudder so I'll be sure that any aileron movement is from the gyro.

Rear-Facing Cockpit Cam - Dynam Hawk Sky RC Airplane - GoPro Hero HD 960 2/2 (3 min 22 sec)
Feb 08, 2011, 12:59 PM
Team Wack-a-Mole
Melnic's Avatar
Cool, I look forward to your "rudder only flight".

BTW, I went back on my 3 axis plane and connected ONLY the GY48V to the rudder.
I had not seen a report of anyone using the GY48V on a rudder only. So with it all set up, it worked pretty good. I had minimal gain in Rate mode and about 30% gain in HH mode. At about 5% travel adjust in rate mode, I got control of the rudder but no movement from moving the plane. I did some crosswind take offs with and without the HH mode on. I did not video it because it was not much different than Ben's results on his e-flite gyros. I think the difference is that you can flip the switch on the gyro gain back and forth 3 times and the servo will center and any drift is eliminated. This is just like the HK401B.

One thing I did have to do with the GY48V just like the HK401B, if I want linear control surface movement, I had to set the travel adjust to 60%. I need to video this cause this is hard to describe, but if you move the stick slowly when you have 100% travel adjust, the control surface in rate mode stops when your stick gets about 2/3 the way over. the last 1/3 of stick movement yeilds NO movement in the control surface. Going through the gyro, Travel adjust does NOT make a difference on that channel (ch4 for rudder here).
So, I used the GY48V for Rudder.
I had the GY48V gain tied to CH5 switch.
Travel adjust for Ch4 was 60%/60%
Travel adjust for ch5 (gain) was 30%(HH) and 5% (Rate).
Flip the switch to HH before take off, if you see the rudder is not centered, flip gear switch (CH5) back and forth 3 times (the gyro light blinks when you are doing this, then 2 times when you are done).

I should probably video the setup so it's clear.
Feb 08, 2011, 02:09 PM
Registered User
Melnic, my experiences with the Futaba GY401 gyro are similar to yours but I set the heading hold gain to 75% and the rate gain to 3%. I have them in seven tail draggers and they work great. I have four of the HK401B gyros which I have "hardened" but have not tried them in a plane yet. Will do that this summer.

Feb 08, 2011, 04:19 PM
What - Me Hurry?
redball8's Avatar
Say Bruce, how do you "harden" the HK401 gyros?

- RB8
Feb 08, 2011, 10:34 PM
Hmm, I wonder If this will fly
at least in my gv48 and hk401's, there is the same piezo chip, and controller IC (different MFG but same chip nun-the-less),different layout though. and both of those gyros benifit from a little TLC, checking and re-doing the soldier joints; re-foaming the case or using silicone to help with vibes.; and putting hot-glue or silicone on the wires where they join to the PCB.

i'm useing one of each (alileron, rudder) in my PZ extra 300 for windy landings, I showed up at the feild and the two outhers there were talking about packing up b/c the wind had shifted to be a fairly strong crosswind... I just tossed a battery in the plane checked the controls and took off (she'll take off of a picknick table) ran a few passes then started toutch and goes... after the second the outher pilots were all starting to feel... um... lacking.... so when I finaly landed I showed them the gyros, i think they are going to be getting some for their big, gas planes... just so a 2lb foam, electric model isin't the only one flying.... (one had a corsair with a 30cc gas motor, the outher a bipe with a 1.20 nitro)
Feb 09, 2011, 07:23 AM
Registered User
You harden them the way killerproblem says. I take the HK401B gyros apart and put 5 minute epoxy on joints where the wing boards join the main board and on the solder joints for the switches and two pots. Then check the foam tape to be sure the unit is not floping around in the case. Takes about 10 minutes a gyro.

Feb 09, 2011, 09:26 AM
Team Wack-a-Mole
Melnic's Avatar
There are a few mods to the HK401 listed in the HK401 thread. Different ways to skin the cat. I was using as well as helping others use the G401B from dealextreme before the GY48V came out.
Post 3323 is what I did and the results:
My GY48V had foam at the bottom of them, but I've heard of others taking the GY48V and still gooping it up. Dating back to the original solid state GR701 Telebee gyro, people have been applying foam tape, goop, what ever to take up slack in the fit of gyros.

Depending on the spacing, I'm using GOOP E6000 which is safe for electronics (some silicone glues are not) or foam tape. as landeck says, epoxy is good for the solder joints so they don't come off. I like foam squeezing the wires to the case on the case exit point so it acts as a strain relief.
Feb 09, 2011, 09:40 AM
Team Wack-a-Mole
Melnic's Avatar
I took out my flysky Rx from my foamie with the 3 axis of gyros

My problem was getting the subrim working. So I put in a spektrum which I usually use with a plane that has a gyro and no issues.

For the aileron/rudder, I wanted Rate/OFF/Heading Hold so I hooked up those 2 gyro gain wires to CH6. For Acro mode in my DX7, that connects to the 3 position flap switch on my Tx. I set endpoints for CH6 to 30% for maiden. Then adjusted subtrim on Ch6 to get the OFF position. OFF as previously described is a LOW gain in rate mode. I adjusted the subtrim till the HH light on the gyro was ON, then moved it to OFF. Once it's off, I then moved it a few more points towards rate. verified that moving the gyros yeilded NO movement in the control surfaces. then I was good to go.

For the Rudder, I wanted OFF/HH just like Ben's described. I used endpoint and was able to just get a low rate gain in one direction , then endpoint in HH to 30% for maiden.

Because of certain charactoristics of gyros on the control surfaces, I have to adjust the endpoint of ail/elev/rud channels down to 60% (I'll detail why later).

It was 23F and windy so I only got one flight. My fingers were in pain and I can't find my "RADIO GLOVE". Rate mode, was cranked up to 50% gain but other than doing a few cross wind landings with the rudder in HH mode, I did not test HH much.

So my issue on my first flight had to do with CG as well as the radio. I'd installed the battery too far aft, plus the subtrim was not working right on that Flysky 9x Tx.

BTW, being 23F, I did a drift test. I initialized the gyros in the shelter, then let it sit for 10 mins. I found the 2 GY48V gyros drifted LESS than the G401B. Maybe due to the thermal inertia of the metal case, maybe cause of the circuitry, don't know. But the G401B.
Feb 10, 2011, 01:38 PM
What - Me Hurry?
redball8's Avatar

HK401 Hardening

Thanks for all the advice, folks!

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