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e-Minicopter Joker > MJ2 Gyro Placement
 
 
kiwidave1
Veteran
Location: Seattle, WA

Hi All!

On a MJ2 I am wondering if anyone has tried to put a gyro sensor on the top center lower frame plate (the plate that the 2 round motor mount support rods screw into) in between the main drive belt?

Second plate from the front in this image

http://www.rosaurophotography.com/html/ap_12.html

I am thinking of moving my 611 there as it is closer to the center of rotation, maybe less vibration to the sensor and will be very well protected in a crash.

Thanks!

David

Never underestimate the power of stupid people in large groups.
11-19-2007 05:52 PM
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fergus
Veteran
Location: Ireland

I have not tried it but if it has clearence and the pad has sufficient area to adhere too then it should work.

As I understand it putting it closer to the centre of rotation will have no effect though as it is the rate of yaw which the gyro senses so its position is irelevent. I would think that the sensor would be better isolated on the boom as the plastic boom block would act as a dampner from vibrations in the frames. Remember the 601 and 611 operate best with 37% gain so trying to provide better dampning to acheive a higher gain setting is not the way to go. If you have a problem with vibration then the best thing is to try and track down the source and remove it. The only advantage is crash protection - I don't think it is such a big issue on the Joker as the flybar is not likely to contact the gyro unlike on the trex 450 for example where the flybar can take out the gyro in a crash. That is why many position the gyro inverted under the boom on that model.

You can get a cover for the 611 sensor to provide some measure of crash protection:

www.turtleskinz.com

I have had one pretty serious crash with my joker2 which bent the boom right at the boom block and broke ALOT of components. My 601 was not damaged but maybe I was just lucky.

Regards

Fergus
11-19-2007 10:19 PM
 
 
nooobs
Key Veteran
Location: Toronto, Canada

Hey Fergus

Long time... Hope all is well...

Just got the 611 and it's awesome. I wished I had picked this up in the beginning.

You said the 611 works best at 37% gain. I have mine set at 66% of my Trex and it works really well. But I thought gain was relative to the position of the balljoint on the servo horn? Is that correct?


Rosauro
11-30-2007 07:11 PM
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Gerd
Senior Heliman
Location: Vellmar/Germany

To test the maximum acceptable gyro gain fly with high speed narrow right curves. When the tail begins to swing you will hear that, then you must reduce the gain as long as this phenomene will dissapear. 37% is a good value. Use the second hole on the 6-arm Futaba horn.
11-30-2007 09:49 PM
 
 
nooobs
Key Veteran
Location: Toronto, Canada

Thanks Gerd. I'll test it out your suggestion this weekend.

Today I tested the gyro against a 50+ Km wind at about 200 ft. I turned the heli so one side is against the wind. The gyro did its job. No tail wag or whatsoever. It held. I didn't touch the rudder, just cyclic and pitch. It was very impressive under those conditions.
12-01-2007 04:44 AM
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fergus
Veteran
Location: Ireland

Hey Rosauro, Hope all is well.

The 611 and 601 work best at 37% gain (as displayed on the gyro control unit not your TX) and this is the advised setting. This figure was arrived at from tests and experiences from 3d flyers and is recommended by Jason Kraus. Higher settings do not give any better hold but as I understand it can over stress the tail servo. Try reducing to 37% gain and see if your hold is any worse. My bet is it will be the same as the higher setting.

The gain on other gyros is different and its value will be dictated by a number of factors including the tail servo, slop in the control link or tail slider, size of tail blades used and tail speed, rotor RPM and general smoothness of the machine etc.

Regards

Fergus
12-01-2007 04:45 PM
 
 
nooobs
Key Veteran
Location: Toronto, Canada

Hey Fergus

Just getting over a flu and a very runny nose. LOL But nothin' is going to stop me from flying.. HA!

I guess I misunderstood. I thought the 37% was on the TX. I've been flying at 100%. Oooops! No wonder the tail held solid perpendicular to a 50+ Km wind gust. LOL I've made the changes and will test it out tomorrow. Hoping the forecast for 100% precipitation is wrong. LOL... I think I can fight off ice pellets. HAHA.

Update on the MJ2: The re-ordered kit cleared customs Friday so it should arrive sometime next week... fingers crossed.

Thinking of getting another set of 611/9256 for the MJ2 but I heard a "new combo" of the 611 with the new brushless BLS251 servo will come out...?


Thank you!

Rosauro
12-02-2007 05:16 AM
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fergus
Veteran
Location: Ireland

Rosauro,

Glad to hear the new Maxi has finally got its visa...LOL

I have not heard much about the knew combo for the 611 yet but if its predecessor is anything to go by it should be great. Angelos at spartan-rc has also released the long awaited DS760 which is said to be a great gyro also.

Good luck with the build and I am available for advice if required as always.

Just got myself a trex450V2 to play with for the winter at the local gym. What a great little machine also have completed my Shuttle conversion to electric so lots to keep me busy for the next few months.

Sorry David did not mean to hijack the thread and go off topic. I hope your gyro question has been covered.

Regards guys

Fergus
12-02-2007 06:29 AM
 
 
kiwidave1
Veteran
Location: Seattle, WA

no worries mate, I think the topic is dead anyway so hijack away

David

Never underestimate the power of stupid people in large groups.
12-02-2007 06:44 PM
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nooobs
Key Veteran
Location: Toronto, Canada

My apologies too David.


Fergus

37% on the control unit and 70% - 80% on the TX did not hold. The heli was slowly turning clockwise.

I increased the control unit to 50% and 70% on the TX works. But I still have to fine tune it.

I managed to find a "window" between the snow storm and ice pellets. LOL

Rosauro
12-03-2007 01:47 AM
HOMEPAGE  
 
 
fergus
Veteran
Location: Ireland

Are you in heading hold (avcs) mode or rate mode?
12-03-2007 04:08 AM
 
 
nooobs
Key Veteran
Location: Toronto, Canada

AVCS... it was weird...
12-03-2007 04:44 AM
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Spartan RC
RR Advertiser
Location: Oxford, UK

Deleted.
12-03-2007 11:30 AM
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Angelos
Key Veteran
Location: nr Oxford, OX11, UK

David,
the sensor that Futaba gyros use operates using an internal magnetic field. Thus I would advise you to keep it further away from such large motor. The gyro does not need to be close to the centre of rotation and should be able to cope with the vibrations on a camera ship.

-Angelos

Spartan RC R&D - Visit us at our local club www.helicollective.org.uk
12-03-2007 11:33 AM
 
 
kiwidave1
Veteran
Location: Seattle, WA

Thanks Angelos,

Great information. I will keep it on the tail. One thing I did find is that the tail kick that I was was getting on the Maxi completely goes away once I hang the camera mount and D80 below it. Strange but since it is working fine with the added weight I guess I will not worry about it too much since I only really plan on flying this ship with the camera mount.

Thanks again Angelos!

David

Never underestimate the power of stupid people in large groups.
12-03-2007 03:14 PM
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nooobs
Key Veteran
Location: Toronto, Canada

Fergus

You're correct! So I started from 50% and it held. Then I slowly brought it down 2% at a time and noticed it was holding right down to 40%. Then I finally brought it down to 37% and it held. Not sure why it didn't hold initially.

Tested it today in a 28 km wind and 41 km wind gust @ -10°C. It held winds at 400ft. It's really smooth now too. Did some nice and slow forward flights and turns. Then some really fast forward flights and turns really nice. Tail really smooth. I'm still at 70% on the TX.

Thanks!

Rosauro
12-04-2007 10:24 PM
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