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-   -   For those braves before me ? GMU 11 installation (https://vansairforce.net/community/showthread.php?t=164104)

Bavafa 09-11-2018 06:35 PM

For those braves before me ? GMU 11 installation
 
I have two questions regarding the installation of GMU11 which will be in a RV14A. I am planning on installing it in the left wing tip but open to other ideas if a better location can be suggested.
First question - with a number of nut plats in that holds the wingtip, should I expect issues? Second but more difficult question, the manual indicates of a .5 degree from the longitude of the plane forward direction. How realistic is to come up with that kind of accuracy? Sure, I can determine the centerline of the plane and draw a line for that on the floor of my hanger. How does one transfer that to the wingtip?
If such accuracy is required, what is the purpose of the calibration? Is the calibration just to get and account for errors that is caused by magnetic field or is there any adjustment for the inaccuracy in the installation?

g3xpert 09-11-2018 07:14 PM

Quote:

Originally Posted by Bavafa (Post 1287834)
I have two questions regarding the installation of GMU11 which will be in a RV14A. I am planning on installing it in the left wing tip but open to other ideas if a better location can be suggested.
First question - with a number of nut plats in that holds the wingtip, should I expect issues? Second but more difficult question, the manual indicates of a .5 degree from the longitude of the plane forward direction. How realistic is to come up with that kind of accuracy? Sure, I can determine the centerline of the plane and draw a line for that on the floor of my hanger. How does one transfer that to the wingtip?
If such accuracy is required, what is the purpose of the calibration? Is the calibration just to get and account for errors that is caused by magnetic field or is there any adjustment for the inaccuracy in the installation?

Hello Mehrdad,

There is some good information in this recent thread about the importance of good GMU 11 installation alignment if you haven't seen it.

Thanks,
Steve

bkervaski 09-11-2018 07:52 PM

Most of us install in the Vans' specified location without any problems.

I had a bad GMU11 and that caused some grief, I couldn't get it to calibrate. Once I got a replacement, it calibrated easily the first time and has worked flawlessly.

Edit: SteinAir/Garmin replaced it for me without any hassle, thanks again to both :)

lr172 09-11-2018 09:03 PM

Does anyone know if all of the Van's planes have their outer wing webs parallel to the aircraft centerline? I know the sweep angle is under 1*

It certainly seems that that the webs are square to the spar and the spar is square to the fuse, except for the sweep angle.

Larry

rocketman1988 09-11-2018 09:25 PM

Be Aware...
 
After spending a bunch of time at the Garmin tent at Oshkosh, many questions were answered. I thought I had my basic avionics figured out...then I went to Stein's booth and asked them what they thought of my G3X setup. We talked awhile and it was brought to light that the GMU communicates via the CAN bus. Normally not a problem in the RV aircraft, however, there is a LIMIT on the total length of the CAN bus. The guys at SteinAir recommended using the GMU 22 in the RV-10 due to the lengths involved. Apparently, when you add all of the lengths up for the CAN bus it starts to get near the limit. The GMU 22 communicates using a different method so that distance is saved whereas the GMU 11 adds to the length. It is also why I will be mounting my Remote Comm2 radio behind the panel.

I am just in the planning stage of my system, and not completely familiar with it all yet but thought it might be a good topic of discussion for those rolling their own system without the help of a shop.

Just wanted to put it out there...

RV6_flyer 09-11-2018 09:47 PM

Quote:

Originally Posted by rocketman1988 (Post 1287865)
...then I went to Stein's booth and asked them what they thought of my G3X setup. We talked awhile and it was brought to light that the GMU communicates via the CAN bus. Normally not a problem in the RV aircraft, however, there is a LIMIT on the total length of the CAN bus.

Just wanted to put it out there...

The "ISO 11898 Standard specifications are given for a maximum signaling rate of 1 Mbps with a bus length of 40 m and a maximum of 30 nodes."

HOW could anyone get more than 40 meters of CAN bus in an RV aircraft?

rocketman1988 09-11-2018 09:58 PM

Well...
 
That is not the information I received, it was more like 60 feet...

If you add it up in the -10, you have the pitch servo at 11 feet, the roll servo about 11 feet, the GMU if tailcone mounted is about 12 feet, yaw servo is 12 feet, plus at the little runs behind the panel...

You can think what you want. I am having SteinAir do my wiring and they have done a bunch of RVs. That's where the info came from...

Bavafa 09-11-2018 10:05 PM

Quote:

Originally Posted by rocketman1988 (Post 1287872)
That is not the information I received, it was more like 60 feet...

If you add it up in the -10, you have the pitch servo at 11 feet, the roll servo about 11 feet, the GMU if tailcone mounted is about 12 feet, yaw servo is 12 feet, plus at the little runs behind the panel...

You can think what you want. I am having SteinAir do my wiring and they have done a bunch of RVs. That's where the info came from...

There has been multiple update to this length and the latest I heard was 66 feet which it is not that hard to reach or exceed.

rocketman1988 09-11-2018 10:07 PM

yes
 
That is what I was told...

Bavafa 09-11-2018 10:08 PM

Quote:

Originally Posted by g3xpert (Post 1287843)
Hello Mehrdad,

There is some good information in this recent thread about the importance of good GMU 11 installation alignment if you haven't seen it.

Thanks,
Steve

Thank you Steve, I did look at that thread but was hoping for more info. Do you know if Garmin has a generic mount that allows for fine adjustment. Although it is not hard to make but if there is one available, why reinvent the wheel


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