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Thread: Directional Gyro and Compass

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    Directional Gyro and Compass

    When I line up the compass and DG then go to autopilot, my dg always shows 6 or 7 degrees instead of 0 where I set it no matter what I do. Is this normal or am I missing something. This is in the Wellington btw. And is it normal that it weaves back and forth while on autopilot....eventually settling out. Any help is appreciated. Thanks.

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    Re: Directional Gyro and Compass

    Quote Originally Posted by UTC View Post
    When I line up the compass and DG then go to autopilot, my dg always shows 6 or 7 degrees instead of 0 where I set it no matter what I do. Is this normal or am I missing something. This is in the Wellington btw. And is it normal that it weaves back and forth while on autopilot....eventually settling out. Any help is appreciated. Thanks.


    I haven't done much with the Wellington but in the ju 88 the auto pilot takes a while to settle down i will go to mode 22 and its swinging 7-10 degrees left and right but eventually settles
    if I am on course mode it its a little more sensitive if i nose up and down i see about 3 degrees difference between DG and compass in general but its not always the same , If i am turning and maneuvering it will diverge from compass
    . For my long trips i am looking at landmarks using the DG the most , a little compass ( dont forget Tobruk has about 2 degrees shift in magnetic field too English channel is about 10 degrees either one can effect you a little for long trips after lots of trips i look at landmarks as I get closer to targets it takes a little while to learn my geography I am beginning to do alittle better in Tobruk now the wire helps in the dessert a few towns are beginning to look familiar ETC but I still get lost too ' I complained about it here once also but several people looked at it and I came to the conclusion i just need to be more patient and let it calm down . I am not patient by nature but now I wait a bit

    TGIF
    Last edited by tgif; Sep-21-2020 at 11:16.

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    Re: Directional Gyro and Compass

    Quote Originally Posted by UTC View Post
    When I line up the compass and DG then go to autopilot, my dg always shows 6 or 7 degrees instead of 0 where I set it no matter what I do. Is this normal or am I missing something. This is in the Wellington btw. And is it normal that it weaves back and forth while on autopilot....eventually settling out. Any help is appreciated. Thanks.
    Hi UTC,

    I'm not sure why this is happening re the 6 or 7 degree offset. At the risk of insulting your intelligence - how well trimmed are you when you turn on the autopilot?

    re the weaving - most times my aircraft will do the weave when i set the autopilot. Some are more noticeable than others - the 110 is pretty tight but the 111 wobbles a bit. The better trimmed I am the less the weave seems to be.

    Sorry if you are all trimmed up and this is not the cause of the issue.

    I wrote the Welly flashcard and dont recall seeing this issue when test flying it but that's not to say it doesnt happen.

    Ezzie

    PS Nice flying the other day in your Welly. I was in the 110 that tried to intercept you on the Tobruk map and made a mess of it for a bunch of reasons. Well done.

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    Re: Directional Gyro and Compass

    Thanks for the replies guys. Up until today I haven’t used aileron trim as the welly roles right at climb speeds so maybe that’s it unless I need to trim rudder? I do find it’s not uncommon for it to weave up to 30 degrees left and right, but yes that could be a trim issue. I’ll work on that. And that may be why I’m only able to climb at less than 1000 fpm.

    That was fun the other day. Scared the crap outta me lol.

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    Re: Directional Gyro and Compass

    Quote Originally Posted by UTC View Post
    When I line up the compass and DG then go to autopilot, my dg always shows 6 or 7 degrees instead of 0 where I set it no matter what I do. Is this normal or am I missing something. This is in the Wellington btw. And is it normal that it weaves back and forth while on autopilot....eventually settling out. Any help is appreciated. Thanks.
    The AP works with the DG, so if you are on course 270 and DG is 270 and you hit the AP you may be hitting course AP left and right to get back to 270; this affects the DG setting. So once you are back on 270 (mag compass) turn AP off, put the DG back to 270 and then you will have to hit the Course AP left/right (with AP still off) to make sure the course AP heading matches the DG. Then turn the AP back on....rinse and repeat. Some work to get the 2 to match with the AP on....then the DG will drift as time goes on. So I just fly by the mag heading and do not worry about the DG matching. This is easier on the German bombers as they have a gauge that goes along with course AP heading.

    After takeoff, trim rudder for the climb to center the needle in the gauge and hit mode 1 AP. This takes over rudder control so rudder trim inputs no longer affect the plane until you turn the AP off. If your needle is no longer lined up (with the AP on) then add aileron trim to center the needle again. Ex: If the needle is to the left, add right aileron. Once you hit mode 22, trim inputs no longer affect the plane until AP is shut off as rudder and aileron control are takin over.

    Even a perfectly trimmed plane with full bombs and 25% fuel will not do over 1000 fpm, at least in my experience (Tobruk map)
    Last edited by Torric270; Sep-22-2020 at 15:50.

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    Re: Directional Gyro and Compass

    the wellie takes a long time to settle longitudinally, much more than the blennie (assume because its that much bigger and rolls a lot to turn). However, not seen the 7 deg offset. My guess would be trim, (unless you are applying rudder input) cos its a bit of a bugger to trim it well. If you have it trimmed at least pretty well on the rudder, for a steady heading hands(feet) off, and to at least feel that letting go of stick wont immediately fall over, get the DG to 0 and simultaneously apply the APilot. It should not jump from 0 immediately at least in my experience. The better the trim the quicker it stabilises, but if you are getting a 7deg squint it will take a life time to settle. And if you use the AP left/right dont apply a lot at once because it will all start again.
    Like others have said, 600ft/min is about best you'll get, to keep stable velocity and attitude whilst climb, engines cool and not over working.
    Then you just got the problem of seeing the target.

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    Re: Directional Gyro and Compass

    I’ll definitely try the suggestions when I can. I’ve decided to set up my lancaster sim pit again. Making some mods and had to tear apart the man cave so it should be up and running in a few days. S!

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