Fluxgates

Any VC10 related discussions.....
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Gwyn
Posts: 74
Joined: Tue Dec 11, 2012 10:03 pm

Fluxgates

Post by Gwyn »

Hi All,

I have a colleague writing a short story about the VC-10 in BOAC times involving an encounter with a rather nasty thunderstorm which takes out the compasses.

Can some technical brain confirm that there was a 'flux gate' on the aircraft at each wing tip. I seem to remember that it was right. Also the main pitot/static tubes were positioned just fwd of the windscreens left and right. The final question concerned the ADF RMI compass rose which I believe was powered by the other side.

Now this will test the brain.

Thanks for any replies.

Gwyn

petet16
Posts: 262
Joined: Sun Dec 09, 2007 10:09 pm

Re: Fluxgates

Post by petet16 »

There was a flux gate on each wing tip, they were attached to the end rib.

The pitot tubes were numbered P1 & P2 each side of the cockpit, and then P3,4,5, & 6 midway down the fwd fuse.

Gwyn
Posts: 74
Joined: Tue Dec 11, 2012 10:03 pm

Re: Fluxgates

Post by Gwyn »

Thanks for that.

Any idea on the power source of the compass RMI's?

Rgds

Gwyn

Jelle Hieminga
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Re: Fluxgates

Post by Jelle Hieminga »

I'll check tonight if the tech manual has an answer for that question.
Buttons . . . check. Dials . . . check. Switches . . . check. Little
colored lights . . . check.

Gwyn
Posts: 74
Joined: Tue Dec 11, 2012 10:03 pm

Re: Fluxgates

Post by Gwyn »

Thanks for your prompt replies.

Now here is a question:

If the aircraft was struck by lightning could that effect the compasses to the point of giving erroneous readings. I seem to recall being struck once and the compasses went haywire and we had to rely on the basic E2B compass. I would assume the RAF machines had this rather basic compass on the fwd overhead panel.

Thanks again.

Gwyn

Jelle Hieminga
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Re: Fluxgates

Post by Jelle Hieminga »

The RMIs were indeed cross connected to the compass couplers. No.1 coupler controlled the FO's ADF RMI and vice versa. That's the signal (heading info) connection but I think that's what you were after. Power to drive the instrument came from the associated accessory unit.

A flux gate or flux valve is basically a set of coils which measures the direction of the local earth magnetic field. A lightning strike is associated with a lot of electrical energy which can set up different magnetic fields in and around the aircraft. The flux gates will then be measuring the wrong magnetic field. I think that's the gist of it...
Buttons . . . check. Dials . . . check. Switches . . . check. Little
colored lights . . . check.

Jelle Hieminga
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Re: Fluxgates

Post by Jelle Hieminga »

ImageUploadedByTapatalk1415296178.802867.jpg
Let's see if this image is legible... It might jog a memory or two.
Buttons . . . check. Dials . . . check. Switches . . . check. Little
colored lights . . . check.

Gwyn
Posts: 74
Joined: Tue Dec 11, 2012 10:03 pm

Re: Fluxgates

Post by Gwyn »

Jelle,

Wow, a minefield of info again.

I can remember the RMI's being cross-powered. We had actually 3 RMI's on the panel if you include the main one. Could well get confusing if doing an ADF approach and looking at the VOR RMI by accident.

Rgds

Gwyn

Murray Keene
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Re: Fluxgates

Post by Murray Keene »

I remember getting doshed by lightning in XR806 over the North sea on the way back from Wunstorf Luftwaffe base. We had been over to recover some role equipment. Heavy cloud cover and a lovely rough transition and if we there had been any passengers onboard they would have been merrily filling the blue bags :roll: . Being the 'techy' in the jump seat I was dispatched to look out of the windows with the loady to see if we had any damage.

Apart from the old girl jumping about a bit the compasses didnt topple and all we saw was a big flash! We were 'flat floor' so nothing in there except 8 seats for crew so we had a good look out and we stuck the periscope up and checked the tail empionage - nothing found! The loady (a newly trained young lad from Finningly) asked if the red light on the tail was supposed to be going on and off - and was it 'broken' #-o I told him calmly YES its supposed to flash its only the navs that stay on - if they flash - 'Houston - we have a problem'!

I had to bribe the Captain with a crate of Grolsch to take us into Brize (he wanted to go into Lyneham because of weather - but said beer and the promise of a roll of aircraft carpet for his car, sealed the deal! So that saved yours truly roughing it in the back of a 3 tonner with the role gear back from Lyneham - cheers skipper! - ( I digress....)

On landing we put a giraffe up to the trailing edge of one wing and we had a hole blasted out near the static wick about 2 inches across and various 'track marks' along the fuselage (usually odd rivets with paint cooked off) also the radome had to be replaced as it had taken a zapping and was crazed. Apart from that no evidence of damage. The fairies came on and had a look and a nose round in the hell hole under the flight deck but again no damage. I never forget the strange smell when we got zapped............although that MIGHT have been the co.......he was very young :lol:

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