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First time I've seen a rigging board


Mcstealth

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  • 4 months later...
6 hours ago, brmitchell04 said:

MCstealth, Im assuming if you download an inclinometer app on your phone, and zero it at zero, if you move the aileron to 20deg your phone would also ready 20deg? Meaning, one should be able to accomplish this using an inclinometer rather than the boards? 

Hmmm. That has possibilities. 

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On 7/12/2023 at 4:50 PM, Mcstealth said:

I know, not particularly interesting, but it's still cool. I've read on here a lot about how a poorly rigged Mooney is "slower" than a well rigged one.  

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Who ever has this plane, it was mine new from the factory in 1988, never had an issue with maintenance, plane was perfect. I sold it in 2006 D

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The rigging on this is more difficult than a Cessna.  You definitely need rigging boards.  My M20F was rigged left elevator down left flap up and the opposite on the other side.  This creates a lot of drag.  There isn't a straight surface to use an inclinometer with any accuracy.

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6 minutes ago, Shadrach said:

My plane is at the upper end of the speed spectrum for the model but it always bothered me that one of the counterweights is about 1/4" above the wing tip skin.

Mine aren't quite aligned at cruise, either, but it flies very straight that way.    The ground rigging is basically to get it to a place good enough to set rigging via flight testing.  If it flies straight and it's not slow, it's probably where it needs to be!  ;)

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2 minutes ago, EricJ said:

Mine aren't quite aligned at cruise, either, but it flies very straight that way.    The ground rigging is basically to get it to a place good enough to set rigging via flight testing.  If it flies straight and it's not slow, it's probably where it needs to be!  ;)

Yeah, likely in an area of turbulent air flow anyway

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I did a lot of testing and adjusting on my old M20F. I found the plane goes the fastest with the ailerons set to the highest allowed setting. Which makes sense. the higher they are the lower the lift they produce, hence the lower induced drag. If I recall, the manual allows something like 1 degree up to 2 degrees down. I tried both extremes and it went a couple of knots faster at the highest setting.

I also adjusted the flaps to the highest setting allowed, which tends to slightly warp the inboard fairings. My M20F would cruise at 152 KTS which is pretty good for an F.

BTW I never used travel boards, just an inclinometer. Travel boards just make it easier.

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4 hours ago, N201MKTurbo said:

I did a lot of testing and adjusting on my old M20F. I found the plane goes the fastest with the ailerons set to the highest allowed setting. Which makes sense. the higher they are the lower the lift they produce, hence the lower induced drag. If I recall, the manual allows something like 1 degree up to 2 degrees down. I tried both extremes and it went a couple of knots faster at the highest setting.

I also adjusted the flaps to the highest setting allowed, which tends to slightly warp the inboard fairings. My M20F would cruise at 152 KTS which is pretty good for an F.

BTW I never used travel boards, just an inclinometer. Travel boards just make it easier.

How much faster is your TN’d J model?

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Normally on every airplane that I’ve rigged out the ailerons trailing edge flies slightly high in flight, meaning the counterweight is slightly down, compared to the way it is on the ground. I’m talking .25” on an airplane much larger than a Mooney, so not much. On the ground they are level to slightly low. 

This is because in flight the ailerons are “sucked” up because the wing is producing lift and any slop in the flight control system will be taken up, the opposite being true on the ground as gravity is pulling them down, as there isn’t much slop we aren’t talking much here, but enough to see maybe if you look.

I’ve tried drooping the ailerons for slightly better lift but it did two things, first it made the airplane heavier in roll and secondly as it washes in the wing it slightly made the stall more abrupt as it had a slight tendency to push the point the stall first occurred out further on the wing, OK three things it slowed the airplane slightly too.

Flaps as they are larger seem to have a greater effect than ailerons do. Slightly reflex the flaps and the tail lowers in flight and the airplane gains speed slightly.

Probably can’t do this on a Mooney as the flap to flap bay has pretty much no clearance, I don’t see them being able to go up any.

A Maule that can reflex its flaps to a -7 degrees really shows this to an extreme, the tail drops a lot in cruise giving a level fuselage. Older Maule’s can’t reflex flaps that came later with a bigger as in longer wing, that long wing increased lift so much it slowed the airplane down, so BD reflexed the flaps and that has the effect of changing the angle of incidence and got some but not all of the speed back, it also had to change stall behavior as reflexing flaps washes in the wing meaning it’s more likely to tip stall, but I guess it must be OK cause it passed flight checks.

See in level flight lift equals weight of course so going slow your nose high to increase angle of attack to keep lift equal to weight and going fast your nose low decreasing lift to keep it equal to weight, but level fuselage gives the least drag of course.

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On 11/21/2023 at 1:05 PM, N201MKTurbo said:

BTW I never used travel boards, just an inclinometer. Travel boards just make it easier.

I’ve never used boards either, usually used a clamp like a gust lock to lock against flaps and called that zero and used a prop protractor and later a digital level. Phone may be OK for checking, but I wouldn’t trim an airplane with one.

On a Mooney I’d be comfortable calling flat counterweight as zero for me, but mine flies fine hands off, I’m not mucking with it. I’m 99% sure that on the ground they are both perfectly level anyway.

Having said that you need some kind of travel board, protractor or maybe just measuring distance for the rudder because an inclinometer isn’t going to work.

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