Location for SP-6

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Wagflier
Posts: 2
Joined: Fri Nov 19, 2021 2:22 am

Location for SP-6

Post by Wagflier »

Hi all,
Newbie here
I just purchased an Extreme Mini system, and after reading the literature on the SP-6, I am perplexed as to where to install the SP-6 Magnetometer.
My project is a Wagabond, which has a welded steel tube fuselage, with a metal cowling. Where on that airframe can I install the SP6 so that it wont be influenced by the steel structure? Thanks in advance for any help.

Rergards,
Merle
rainier
Site Admin
Posts: 647
Joined: Fri Aug 28, 2020 7:03 pm

Re: Location for SP-6

Post by rainier »

Traditionally these kind of constructions make it near impossible to locate a functioning compass of any sort inside the fuselage.
You may find the SP-6 can calibrate itself fairly well during the calibration flight but even if the result looks good it will not last very long as the entire frame is one big magnet - polarized by the Earths magnetic field itself for the main part. The steel frame also causes very significant deviation as it will change the direction of the field.

Usually in a case like this my advise is to install the SP-6 in a wing tip.
Wagflier
Posts: 2
Joined: Fri Nov 19, 2021 2:22 am

Re: Location for SP-6

Post by Wagflier »

Since the wings have no ferrous metals in them, does the SP-6 have to be clear at the tip, or can it be mounted closer to the root?
ktz737
Posts: 12
Joined: Mon May 08, 2023 9:07 pm

Re: Location for SP-6

Post by ktz737 »

Hi !
I have a problem with my SP6 installation.
It was initially positioned below the right seat by the previous owner, so that the precision was really random.
I decided to put it in the rear of the fuselage, at about 1 m away from the cockpit.
And the result is worse, I'd say unusable. The headings are totally wrong, from 20 to 70° error.
I really don't understand the reason. It is alone, far from steel items (the nearest is the pitch servo, at about 60 cm).
My plane is a 2 seats MCR, all carbon.
Any idea ?
sbeaver
Posts: 4
Joined: Wed Sep 09, 2020 11:05 am

Re: Location for SP-6

Post by sbeaver »

https://www.sciencedirect.com/science/a ... ayers%20of

This paper suggests that carbon fiber blocks magnetic fields rather thoroughly.
ktz737
Posts: 12
Joined: Mon May 08, 2023 9:07 pm

Re: Location for SP-6

Post by ktz737 »

Oh Thanks.

I am surprised because more and more light airplanes are made of carbon and I have never found any restriction of use with a magnetometer,

Maybe Rainier could confirm ?
Paulienuts
Posts: 12
Joined: Thu Jul 27, 2023 5:32 pm

Re: Location for SP-6

Post by Paulienuts »

Carbon blocks radio frequencies as well. No surprising it blocks the earth's magnetic field.
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