REFLECTOR: Aileron Rigging

jewen at comporium.net jewen at comporium.net
Wed Jul 16 21:55:22 CDT 2008


Hi Ronnie,

Can you provide a bit more info about the up/down relationship.  How much more up aileron than down?  
I have drafted and measured the effect of various approach angles and can see the relationship of up/down can be controlled by the approach angle to the end of the bellcrank and the relationship of the cable end to the pivot point.  A trade off is heavier aileron actuation as the approach angle to the end of the bellcrank moves further from 90 degrees (perpendicular to the torque arm of the bellcrank.)  Knowing the optimum (or duplicating your angles) would be helpful.

I worked with angular displacement knowing that the linear measurement of 2.5 up and 2.5 down would be proportional to the angular movement.  That said, I was able to find a range that did give more angular displacement than the factory position without moving the attach point closer to the pivot that had more up than down aileron.  

Thanks,
Joe  

---- Original message ----
>Date: Thu, 10 Jul 2008 09:31:37 -0400
>From: "Ron Brown" <romott at mi-connection.com>  
>Subject: Re: REFLECTOR: Aileron Rigging  
>To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>
>The following is for non -5 Velocities (the -5 has a better arrangement at 
>the keel - the cable housings attach at nearly 90 degrees to the bell crank 
>on the cut down keel) :
>
>My problem started when I tried to install my aileron cables and bell cranks 
>per the manual. It is impossible to obtain equal up and down travel with the 
>cable attach installed at the keel per the manual.  The cable housing does 
>not attach at a 90 degree angle to the bell crank - therefore you cannot get 
>equal up and down travel from the neutral position.  Dave Black (where are 
>you Dave, haven't heard from you lately?)  figured out the problem.
>
>And when I was building, folks were complaining about their Velocities 
>wallowing on final while at less than 100 knots. This wallowing is a symptom 
>of adverse yaw (read my earlier note).  So I decided to fix the problem - 
>hence the more UP travel than DOWN travel.  As with a Cessna, I can pretty 
>much keep my feet on the floor all the way down to the runway.  If it is 
>gusty, I will use rudder to aid the rudders in speeding up roll rates at low 
>airspeed.
>
>Ronnie
>
>
>----- Original Message ----- 
>From: "Andrew Ellzey" <ajlz72756 at yahoo.com>
>To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>Sent: Thursday, July 10, 2008 8:30 AM
>Subject: Re: REFLECTOR: Aileron Rigging
>
>
>> Keith,
>> The drill location and aileron rigging are different if you have the cut 
>> down keel option or if you bought the complete -5 option with your kit. 
>> I'm not sure why you are wanting more up travel than down travel, and not 
>> just following the manual. I have the cut down keel option, so my bell 
>> cranks point down instead on up on the standard keel. My wings are 
>> complete, and I was able to rig my bell crank at 90 degrees and I have 
>> equal travel up and down per the manual. I haven't drilled the holes in 
>> the firewall for my control cables yet, but it is obvious that it will be 
>> about 1 inch under the the spar per the plans. There is a kcp that gives 
>> this information, It wasn't in the manual at the time I bought my kit. 
>> The -5 option had just come out. If you are interested and you do have the 
>> cut down keel option I can send you some pictures. If you don't have the 
>> cut down keel option, sorry that I muddied the water. I know that there 
>> are aircraft that are
>> designed with differential aileron rigging (Mooney's) but I would talk to 
>> the factory before I changed the design of your control surface operation. 
>> My thoughts, not trying to step on any toes. This is your life.
>>
>> Andy Ellzey
>>
>>
>>
>> ----- Original Message ----
>> From: Keith Hallsten <KeithHallsten at quiknet.com>
>> To: Velocity Aircraft Owners and Builders list <reflector at tvbf.org>
>> Sent: Wednesday, July 9, 2008 11:50:21 PM
>> Subject: Re: REFLECTOR: Aileron Rigging
>>
>> Ronnie,
>>
>> You drilled through the spar web for a hole to run the aileron cables
>> through? I'm sure the cables in my XL run entirely below the spar.
>>
>> Keith Hallsten
>>
>>
>> -----Original Message-----
>> From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
>> Behalf Of Ron Brown
>> Sent: Wednesday, July 09, 2008 11:03 AM
>> To: Velocity Aircraft Owners and Builders list
>> Subject: Re: REFLECTOR: Aileron Rigging
>>
>> No, the cable comes out just above the lower spar cap. If you get too low,
>> you'll have problems making the transition back to the keel bracket.
>>
>> Ronnie
>>
>> ----- Original Message ----- 
>> From: <cgputney at peoplepc.com>
>> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>> Sent: Wednesday, July 09, 2008 1:13 PM
>> Subject: Re: REFLECTOR: Aileron Rigging
>>
>>
>>> Thanks Ron! I appreciate the info. Apparently, the cables penetrate
>>> the
>>> firewall below the lower spar cap?
>>> Gordon
>>>
>>> ----- Original Message ----- 
>>> From: "Ron Brown" <romott at mi-connection.com>
>>> To: "Velocity Aircraft Owners and Builders list" <reflector at tvbf.org>
>>> Sent: Wednesday, July 09, 2008 7:37 AM
>>> Subject: Re: REFLECTOR: Aileron Rigging
>>>
>>>
>>>>
>>>>
>>>> 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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>>>>>
>>>>
>>>
>>>
>>>
>> ----------------------------------------------------------------------------
>> ----
>>>
>>>
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>>>
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>>
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>>
>> _______________________________________________
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>
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