Jermo's DX7 Setup Video

[Jermo]

changlog post:
I'll be editing this up to the time I shoot it. If I miss stuff just post and I'll update this.

Rev3
Changes:
1. Gy401 setup - correct settings explain why
2. GY401 add alternate config with standard channel (gear/aux/other)
3. CCPM Swash adjustments - explain settings more
4. Recap properly setup head

[bullaculla]

Man, 2 months too late! :mrgreen:
But I watched it anyway and now I have confidence that I set up my radio correctly. I have my 611 gyro set up the way BarnOwl mentioned. Gear to gear with the appropriate endpoints.
It works so I will probably leave it.

[Jermo]

Originally Posted by bullaculla

<cut>
It works so I will probably leave it.

exactly, there are several ways to setup the Gyro. At the end of the day the method you feel happy with is best.
Jermo

[TMoore]

Paul, first you should NEVER run a 601 or 611 at that high a gain! You will burn up your servo. 37% MAX man.....

The original premise for this gain setting was for use on a Fury by Jason Krause for 3D flying. You would be hard pressed to convince plots like Hashimoto (3 time WC), Sensui, Dobashi or Wayne Mann that 37% gain is the max because it all depends on what length servo arm you use and how much throw you need. The Japanese pilots will run 100% gains for certain flight profiles depending on what they are trying to achieve.

I've seen the gain settings anywhere from 25% all the way 55% on various machines of mine so at the risk of arguing with Finless yet again, IMHO, the best way that I have found is to test fly the machine and take a temp gun to the tail servo. If the temps measure more then 140 degrees F you are nearing the max temperature threshold just prior to servo failure. The servos won't survive much more than 150 degrees F before the motors and amps start to go away. At this point the servo isn't worth fixing due to the cost of the motor and amp. I'm currently flying 5 of the 601's and 3 of the 611's. The servos can last several hundred flights if taken care of before they require replacement.


TM

[Jermo]

Tmoore are you talking about the gain in the TX or the Gain setting On the Gyro?
Jermo

[TMoore]

The gain setting in the TX doesn't matter. All I'm concerned with is the gain at the gyro.

TM

[WillJames]

Unless you are using the GY menu on a Futaba Radio, you are going to have to look at the Gyro display to see what gain setting you have while you adjust the endpoints on the remote gain channel of your choice to achieve desired gain setting.

[TMoore]

Unless you are using the GY menu on a Futaba Radio, you are going to have to look at the Gyro display to see what gain setting you have while you adjust the endpoints on the remote gain channel of your choice to achieve desired gain setting.

Correcto mundo!

TM

[Finless]

I wont argue the higher gain on other helis.... Go run 80% on a Trex600 and see how long your servo lasts... I told Paul that specifically because that is a Trex600.

Bob

[TMoore]

I wont argue the higher gain on other helis.... Go run 80% on a Trex600 and see how long your servo lasts... I told Paul that specifically because that is a Trex600.

80% is a long way from 37%. It will ulitmately depend on the servo arm ball radius and how hard you push the machine.

If you are trying to hold a hover in a mean crosswind as you might do in competition 37% may not be enough gain.

TM

[Finless]

Most of us with the new tail grips (larger disk) are runing no more than 28% gain (as read on the 611 display). Pauls older tail was around 36%. Tail holds fine in any backwards conditions I have seen it put through. Going much higher and you get wag when doing backwards flight but of course Paul wont notice this just hovering and simple FF BUT it is over working the tail servo with the gain amount he has.

Needless to say I aint arguing other helis, gain, etc I was simply telling Paul that on his 600 anything over 37% is too much for this heli and tail design. Paul is local to me so it wasnt meant to be a general post but directed at Paul.

So Terry... what you hunting out anything I post trying to find a hole somewhere to contradict? Sheesh man...

Bob

[TMoore]

Friendly debate as far as I can tell, nothing more.

TM

[slikrx]

OK, I have to admit I'm kinda lost on the "50% +32% = 82% " portion.

By my thinking (and I'm a newb) it should be 66, not 82.

By using the drawing from the video:



Since with the DX7 you are compressing the "top 50%" of the normal curve by half, shouldn't reduce the gain increase by half?

I read through this and didn't see it mentioned. I am getting a DX7 and then shortly after, the 401 gyro, so I'll be fighting through this exact thing...

*confused*

[Jermo]

Slikrx,
sorry for the confusion. If you are using the Gyro Sense menu 1 point of Gyro Sense is equal to 1.44 gain on the Futaba GY401. To this end if we want 32 gain on the gyro gain channel then we need (32/1.44) to get the magic number for the Gyro Sense menu. Now comes a curve. The Gyro Sense menu only goes from 0 to 100%. Numbers 0-49 are for Normal Mode, while numbers 51-100 are for Heading Hold mode. so (32/1.44) = 22.222' (we'll round this down to 22). Using 50 as our center point 32gain (that we established takes 22 points in the Gyro Sense menu), for each mode is 22 from center.

Thus 32 gain in Heading Hold mode is 50 + 22 = 72
and 32 gain in Normal mode is 50 - 22 = 28

Keep in mind these are starting points and may change with your tail servo and configuration.

Using the Gyro Sense menu allows you to map the gain anytime and control it with the Flight mode switch or the throttle hold switch.

The suggesiton is to set the Heli up for Neutral tail in Normal mode in hover, then setup the heli in heading hold mode and keep it there. This allows for stability in the event the gyro is reset in flight by a power glitch.

Many have suggested this normal mode setup in hover is not necessary because you can just hit throttle hold and land.

I hope this helps.
Jermo

[slikrx]

Originally Posted by jermo

Slikrx,
sorry for the confusion. If you are using the Gyro Sense menu 1 point of Gyro Sense is equal to 1.44 gain on the Futaba GY401. To this end if we want 32 gain on the gyro gain channel then we need (32/1.44) to get the magic number for the Gyro Sense menu. Now comes a curve. The Gyro Sense menu only goes from 0 to 100%. Numbers 0-49 are for Normal Mode, while numbers 51-100 are for Heading Hold mode. so (32/1.44) = 22.222' (we'll round this down to 22). Using 50 as our center point 32gain (that we established takes 22 points in the Gyro Sense menu), for each mode is 22 from center.

Thus 32 gain in Heading Hold mode is 50 + 22 = 72
and 32 gain in Normal mode is 50 - 22 = 28

Keep in mind these are starting points and may change with your tail servo and configuration.

Using the Gyro Sense menu allows you to map the gain anytime and control it with the Flight mode switch or the throttle hold switch.

The suggesiton is to set the Heli up for Neutral tail in Normal mode in hover, then setup the heli in heading hold mode and keep it there. This allows for stability in the event the gyro is reset in flight by a power glitch.

Many have suggested this normal mode setup in hover is not necessary because you can just hit throttle hold and land.

I hope this helps.
Jermo

It helps, sorta... I forgot the 1.4 factor gets you to 22... but shouldn't THAT then be cut in half to account for the reduction from 100% to 50%?

I guess it doesn't really matter, since it gets you close and I will need to be adjusted anyway...

Sorry for being dense!

[Jermo]

Originally Posted by slikrx

It helps, sorta... I forgot the 1.4 factor gets you to 22... but shouldn't THAT then be cut in half to account for the reduction from 100% to 50%?

I guess it doesn't really matter, since it gets you close and I will need to be adjusted anyway...

Sorry for being dense!

No it shouldn't be cut in half. The implied conversion from a range that goes -100 through 0 to +100 mapped to 0 through 100 is 1:2, However, the GY601 Gyro is exactly the same and has a display. Experimentation has illustrated that it's not 1:2 as expected. 1:1.44 works.

This is just a starting/general setting and is not meant to necessarily replace tuning for your specific setup.
Jermo

[WillJames]

The suggesiton is to set the Heli up for Neutral tail in Normal mode in hover, then setup the heli in heading hold mode and keep it there. This allows for stability in the event the gyro is reset in flight by a power glitch.

If the voltage gets low enough to reset the gyro, it is going to piro unless you are extremely extremely lucky. I know this from experience of 3 low voltage resets. Whether you setup for neutral in rate mode or not,(which I do on all but a 450) a reset is going to send you piroing. RCHeli mag has their information wrong.

[Jermo]

Originally Posted by WillJames

If the voltage gets low enough to reset the gyro, it is going to piro unless you are extremely extremely lucky. I know this from experience of 3 low voltage resets. Whether you setup for neutral in rate mode or not,(which I do on all but a 450) a reset is going to send you piroing. RCHeli mag has their information wrong.

Will,
But hitting TH will save you right? if so I'll clarify that in rev3.
Jermo

[jayrob]

Originally Posted by jermo

Skid - I'll put that in version 2 I'm working on that now. Just waiting for feed back on this one. V2 is alot different than V1 so far.. more detail..etc
Jermo

Jermo, thanks for the DX7 video! I'm a newbe setting up my T-rex 450 se with the DX7 don't know what I would have done with out your video. (and Bob's videos) But now I accually understand what things mean. One question: On the G3 simulator, the switch for 3d flight mode is on the left front. But on the DX7, the switch is different switch (second from the left on top face) Is this normal, or do I have something set wrong?
Thanks,
Jay

[slikrx]

Originally Posted by jermo

No it shouldn't be cut in half. The implied conversion from a range that goes -100 through 0 to +100 mapped to 0 through 100 is 1:2, However, the GY601 Gyro is exactly the same and has a display. Experimentation has illustrated that it's not 1:2 as expected. 1:1.44 works.

This is just a starting/general setting and is not meant to necessarily replace tuning for your specific setup.
Jermo

Cool! Thanks so much!