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Skyview AHARS Tray

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paul330

Well Known Member
I am planning the mounting tray for the Skyview AHARS and intend to fit it in the tailcone at the top of the bay behind the baggage bulkhead.

Can someone tell me the angle of the longerons with the aircraft in level flight or what relative angle is needed between the longerons and the mounting tray?
 
The bottom of the door frame opening on the -10 is reference for level on the pitch axis and the cross frame that the rear seat backs rest against is the reference for level in the roll axis.
 
OK, thanks for the info - that was the thread I was looking for but couldn't find.

I intend to build something very similar. The only thing I'd do diffently would be to extend the side bracket ahead to take the grommets rather than put large holes in the J-stiffeners.

I will be putting together the front and mid-fuse this week and then it's longeron bending time :eek: After that, I should have a good idea of the correct orientation.
 
N427EF said:
David,
Check out an earlier thread.
http://www.vansairforce.com/community/showthread.php?t=57080&highlight=Tip:+dual+dynon+adahrs+mount
On the Rv-10 the door sill is to be used for leveling.
The longerons are about 3 degrees off.
The method described in that thread worked very well and the installation is very accurate.
Click to expand...

Wondering what the angle of the ADAHRS mount is in relationship to the tail cone longerons? I would like to get mine fabricated and installed now before I start on the fuselage section. If the tail cone longerons are level, what is the tray at?
 
paul330 said:
I am planning the mounting tray for the Skyview AHARS and intend to fit it in the tailcone at the top of the bay behind the baggage bulkhead.

Can someone tell me the angle of the longerons with the aircraft in level flight or what relative angle is needed between the longerons and the mounting tray?
Click to expand...

Paul,
I'm not up on the Skyview, but the magnometers for the D-10, etc., need to be pitched to the same angle as the instrument - not the flight path. The AHARS I am familiar with need to be on the flight path..
I suspended two pieces of angle on cross-angles attached to the longerons - a lot of folks do the same thing. You will put the magnometers/AHARS on later and adjust the angles per the instructions for each device. Go ahead and put the angles, or shelves, in now. You can adjust the devices later.

John
 
ADAHRS/MAGNETOMETER

Having the magnetometer integrated into the adahrs unit makes for a slightly
different installation. More simple as far a wire routing but more difficult as far as finding a spot that is far enough away from magnetic interference.
In the 10 there really is only one spot, the one you are considering.
Perhaps Scott McDaniels could tell us the precise difference between longeron and door sill angle. An exact aluminum bracket could be fabricated without measuring and leveling the whole aircraft.
An adjustable shelf would be ideal but finding non magnetic hardware to do that presents yet another challenge. If you can manage to build the tray while the skin is still off that would be great but once you have to do the work from inside the tail cone it qickly becomes a yoga exercise.
You do want the adahrs up as far as possible to get them away from the seat belt cables as well as to leave access open to the rear.
If you find an easier way to install that tray let us know.
 
N427EF said:
In the 10 there really is only one spot, the one you are considering.
Click to expand...

Won't work for my -10; I've got too much going on there. I saw a -10 in Sedona with the G900X magnetometer back near the HS, but I'm planning rudder trim, so that's probably out, too. Looks like my best bet will be 3/4 out on the wing with aileron trim (guessing the trim motor may be less noisy than the roll servo) and halfway between the strobe conduit and the TE. Actually, if you look at Garmin's guidelines, there is no possible location (they want 3' from all ferrous materials and sensor wires; 6' from all power leads and motors) but somehow they get installed and work correctly.
 
My Chelton magnetometer is under the rear deck below the horizontal/vertical stabs and works fine. I have a Dynon magnetometer mounted to one of the right wing inspection panels and it also works fine EXCEPT!! the wires from the landing lights are fairly close and they drive the Dynon magnetometer off several degrees when the landing lights are on. :(
 
Wow, seem to have started something!

Wing tip mount doesn't work for the Skyview - has to be more or less centre-line.

I don't think the panel angle makes a difference since the screens are just that - screens. They have no sensing kit in them at all. So it seems that the AHARS has to be level with the attitude in level flight to show level on the screens. Of course, it is not critical since the attitude will only be correct for one airspeed or configuration (unless the clever electronics of the Skyview sense flightpath rather than attitude.....)

Cross-ship is easy. And it seems the tailcone longerons are about 3 deg from the door sill datum - I assume that is angled up towards the tail. In any case, they can always be shimmed later.

As a final question, what do people use to attach the units to the brackets - brass screws and nuts? Or can you use stainless steel? And are nutplates magnetically ferrous?
 
Paul,
Make sure you see the difference between Dynon ADAHRS and other units.
Dynon has the magnetometer integrated in the ADAHRS unit whereas others have the magnetometer separate making for more choices for installation.

I used all brass hardware to mount the brackets and adahrs unit.
After I found out that my stainless steel rivets are mildly magnetic.
Nutplates of course are notoriously magnetic and not usable near a compass.
Aluminum rivets would work but I did not feel comfortable using those.

You can shim later but measuring level and square after the deck is on will be more difficult than getting it right the first time.
 
WHY?

Why the world (I would use a stronger word here but trying to keep it G-rated) did Dynon combine the ADAHRS and the magnatometer? Seems to be a complete PIA even in an all aluminum airframe. Absolutely baffling why their engineers did this. If I am not mistaken, all other manufacturers of these EFIS systems have separated them, or at least offer the option of a remote mounted magnatometer. Sounds like Garmin may be an exception.

I wish everyone would squawk more and maybe Dynon would see their error and offer a remote mount. I used the D100 In my -7 and a Kitfox Series 7 and the remote mount made for nearly infinite installation options with not interference problems. I am now building a Bearhawk (another rag and tube plane) and would love to use a Skyview but you think finding a location on an RV is hard?... try it on a chromoly airframe! This is literally impossible to have 0 magnetic interference, the best you can hope for is that you can calibrate it out.

Sounds like everyone is having heartache finding that "perfect" spot. I say we let Dynon hear our complaints and maybe they will fix the issue and offer the option for remote mount. I know of at least 3 people who would buy an SV1000 today if they had this option and I am sure there are countless more. Anyone at Dynon listening????
 
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