REFLECTOR: Aileron Rigging

Wed Jul 9 07:37:18 CDT 2008

Yes, my changes did result in more up than down aileron travel. I don't have 
the measurements since I gave the new owner all of my manuals and paper 
notes.

I have attached two pictures that show the aileron in the  up and down 
positions.  The 1/4" socket extension clamped to the inverted aileron cable 
brackets approximate the revised location of the aileron control cables when 
attached.

Ronnie

----- Original Message ----- 
From: <cgputney at peoplepc.com>
To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
Sent: Tuesday, July 08, 2008 8:49 PM
Subject: Re: REFLECTOR: Aileron Rigging

> Ron, did your change result in 2.5" down and up?   I want to do this 
> change
> as well and would appreciate some numbers on your actual final 
> measurements.
> Thanks,
> Gordon Putney
>
> ----- Original Message ----- 
> From: "Ron Brown" <romott at mi-connection.com>
> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
> Sent: Sunday, July 06, 2008 12:13 PM
> Subject: Re: REFLECTOR: Aileron Rigging
>
>
>> Hi Joe,
>>
>> From my RC modeling days, I learned that to minimize adverse yaw, the
>> ailerons should go up more than they go down.  Although we have Frieze
>> ailerons (the nose sticks down when the aileron is up), there is still a
>> tendency toward adverse yaw.  Especially since the attach point for the
>> aileron cables at the back of the keel is not 90 degrees.
>>
>> So, to improve the situation, I installed my aileron bell cranks beside
>> the
>> engine with a good bit of bias toward the front.  I also lowered the
>> attach
>> point for the aileron cable jacket.  This helps relieve the "error" at 
>> the
>> keel as well as move the bellcranks away from the engine (but your rotary
>> is
>> narrower than the Lycoming so not an issue).  The aileron bell crank is
>> more
>> like 90 degrees to the cable when the aileron is down.
>>
>> Here's a note that I wrote in 2003 that is repetitive but adds some more
>> info:
>>
>> When I rigged my ailerons, I found it difficult to obtain the equal 2.5"
>> up
>> and 2.5" down that is called for in the manuals - for my 173 Elite RG.
>> Since the push/pull cables at the rear of the keel do not have a 90 
>> degree
>> approach angle, the connection of the push/pull cable at the aileron
>> torque
>> tube on the wing, results in ailerons that travel down more than they do
>> up.
>> This causes an adverse yaw condition which will lead to wallowing at low
>> speeds.
>>
>> I learned this lesson a long time ago when flying RC models.  If you take
>> off at just above stall speed, the model would turn the opposite 
>> direction
>> from that commanded.  This is because the aileron that is going down has
>> more drag than the one going up. This causes the left wing to slow down 
>> if
>> you are commanding a right turn at slow speeds.  This is called adverse
>> yaw
>> and is common in older airplanes.  To get a coordinated turn, even at
>> speed,
>> you need to lead with a lot of rudder before applying aileron deflection.
>> Or, you rig the ailerons so that there is more up travel than there is
>> down
>> travel, which will reduce this yaw effect.
>>
>> Cessnas and some other planes (including our Velocities) have a Frieze
>> aileron, which features a lip that hangs down below the wing when the
>> aileron is deflected upwards.  This helps balance the drag from the other
>> aileron which is hanging down in the airstream.
>>
>> Velocities handle fine at higher speeds even with no rudder input.  But 
>> at
>> lower speeds, if the ailerons are rigged with the 90 degree approach 
>> angle
>> at the wing, then this results in more down than up aileron travel, and
>> the
>> adverse yaw condition that some folks have called "wallowing" on final.
>>
>> A while back, Dave Black pointed out the problem at the keel.  One fix is
>> to
>> build a wide bellcrank at the back of the keel so that the aileron cables
>> could be attached at a 90 degree approach angle while in the neutral
>> (centered) condition.
>>
>> The other way is to attach the aileron cable at the wing so that the
>> approach angle is more than 90 degrees.  Mine are attached at about 120
>> degrees, which results in more up travel than down travel.  My Velocity
>> handles fine at low speeds, with just aileron control, similar to my
>> Cessna
>> 172.  If I need a sharper turn, I'll kick in more rudder, just like in my
>> 172.  But normally, no rudder is needed, all the way down to the runway.
>> (But I also installed VG's before my first flight, these also improve low
>> speed aileron control).
>>
>> Ronnie Brown
>>
>>
>>
>>
>> ----- Original Message ----- 
>> From: <jewen at comporium.net>
>> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>> Sent: Saturday, July 05, 2008 11:42 AM
>> Subject: REFLECTOR: Aileron Rigging
>>
>>
>>>I am rigging up my aileron this weekend (173RG.)  I recall several 
>>>threads
>>>on the subject in the past, but can't find my notes.  Does anyone mind
>>>refreshing me on the nuances that the manual does not address.
>>>
>>> Thanks,
>>> Joe
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>>
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>
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