REFLECTOR:Re: Aileron Rigging Frustration
reflector@tvbf.org
reflector@tvbf.org
Sat, 3 Apr 2004 10:11:10 EST
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Well, no, I have not got the ailerons rigged correctly yet, and have talked
with Brendan a couple times. Here's the scoop:
I have the 173 Elite Model, so others may be different.
I followed the plans in my manual and could not get 2.5" of travel (in fact
the maximum I could get was 2-7/16 up and 2-5/16 down).
I was told that there should be no differential aileron (more up than down).
I ended up getting the "new" instructions off of the Velocity Site, and the
instructions are Very different. Following them dictated that I buy more
aluminum and make a new set of Cable Clamp Brackets. After following the
instructions to the letter, I could still not get proper travel, so I called the factory
again. The response was that my approach angle (cable to wing root bellcranks)
has to be off. Well, 90 degrees is pretty easy to measure and believe me...
I have measured it at least a hundred times over the last few weeks.
Finally, out of frustration (and thinking I just may be loosing it) I had my
Dad check things out. He's an Engineer at Sandia National Labs, and can figure
these things out Much faster than I would be able to do. He found some
interesting things:
In order to get 2.5" of up and down travel (5" total movement), you have to
have 3.14" of travel in the aileron cables. Since the cables have only 3" of
travel, the maximum up/down travel possible is 4.75" (or 2-3/8 up & 2-3/8
down). The instructions say that you can get 2.5" up/down travel out of a
properly rigged system, and that is impossible!
This is based on some other things:
1, the bell crank at the back of the Keel has a 4" lever arm.
2, the bell cranks at the wing root also have a 4" lever arm.
3, the ratio between the bell crank turning, and the aileron movement is
1:1 (one to one)
I measured mine, and it is essentially 1:1.
4. The travel possible is based on zero slop in the system! It is the
best you will ever get.
5. Hope that my keel plate is correctly drilled from the factory. The
approach angle of the aileron cables at the keel is 82-degrees per side. This
will induce a small amount of differential in the system and slightly limit
total possible travel.
Conclusion: Well, after weeks of work trying to obtain the travel stated in
the instructions, I am now frustrated and enlightened. It is not possible!
Today I will go out and try and adjust the system to get the maximum
possible with what the factory provided me: That is 2-3/8 up/down travel.
Question: those flying the 173 Elite, is that sufficient?
Possible changes: In order to achieve more aileron travel, I have thought of
3 possibilities:
1, Increase the length (lever arm) of the keel bellcrank by about 3/8"
(would get more travel and more leverage)
2, Decrease the lever arm of the wing root bell cranks by about 3/8" would
get more travel at the aileron torque tube, but less leverage and therefore
stiffer ailerons). This could be done by welding the hole shut and drilling a
new one as hole edge distances could not be maintained by simply drilling a new
hole.
3, Get cables that have more travel than the 3" the factory provides.
So, there is the next chapter in frustration. I will let you know the next
chapter soon. Basically I am no more nuts than I was before, and the limitation
is in the system.. not the builder. Whew!!
Kurt Winker
173 FGE ... flippin flipper fiddelin'
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<DIV>Well, no, I have not got the ailerons rigged correctly yet, and have ta=
lked with Brendan a couple times. Here's the scoop:</DIV>
<DIV> </DIV>
<DIV>I have the 173 Elite Model, so others may be different. </DIV>
<DIV> </DIV>
<DIV>I followed the plans in my manual and could not get 2.5" of travel (in=20=
fact the maximum I could get was 2-7/16 up and 2-5/16 down). </DIV>
<DIV> </DIV>
<DIV>I was told that there should be no differential aileron (more up than d=
own). </DIV>
<DIV> </DIV>
<DIV>I ended up getting the "new" instructions off of the Velocity Site, and=
the instructions are Very different. Following them dictated that I buy mor=
e aluminum and make a new set of Cable Clamp Brackets. After following the i=
nstructions to the letter, I could still not get proper travel, so I called=20=
the factory again. The response was that my approach angle (cable to wing ro=
ot bellcranks) has to be off. Well, 90 degrees is pretty easy to measu=
re and believe me... I have measured it at least a hundred times over the la=
st few weeks. </DIV>
<DIV> </DIV>
<DIV>Finally, out of frustration (and thinking I just may be loosing it) I h=
ad my Dad check things out. He's an Engineer at Sandia National Labs, and ca=
n figure these things out Much faster than I would be able to do. He found s=
ome interesting things:</DIV>
<DIV> </DIV>
<DIV> In order to get 2.5" of up and down travel (5" total movement), y=
ou have to have 3.14" of travel in the aileron cables. Since the cables have=
only 3" of travel, the maximum up/down travel possible is 4.75" (or 2-=
3/8 up & 2-3/8 down). The instructions say that you can get=20=
2.5" up/down travel out of a properly rigged system, and <STRONG>that is imp=
ossible</STRONG>! </DIV>
<DIV> </DIV>
<DIV>This is based on some other things: </DIV>
<DIV> 1, the bell crank at the back of the Keel has a 4" l=
ever arm.</DIV>
<DIV> 2, the bell cranks at the wing root also have a 4" l=
ever arm.</DIV>
<DIV> 3, the ratio between the bell crank turning, and the=
aileron movement is 1:1 (one to one)</DIV>
<DIV> I measured mine, and it is e=
ssentially 1:1.</DIV>
<DIV> 4. The travel possible is based on <STRONG>zero</STR=
ONG> slop in the system! It is the best you will ever get. </DIV>
<DIV> 5. Hope that my keel plate is correctly drille=
d from the factory. The approach angle of the aileron cables at the keel is=20=
82-degrees per side. This will induce a small amount of differential in the=20=
system and slightly limit total possible travel. </DIV>
<DIV> </DIV>
<DIV>Conclusion: Well, after weeks of work trying to obtain the=20=
travel stated in the instructions, I am now frustrated and enlightened. It i=
s not possible! </DIV>
<DIV> Today I will go out and try and adjust the system to get t=
he maximum possible with what the factory provided me: That is 2-3/8 u=
p/down travel. </DIV>
<DIV> </DIV>
<DIV>Question: those flying the 173 Elite, is that sufficient? </DIV>
<DIV> </DIV>
<DIV>Possible changes: In order to achieve more aileron travel, I have=
thought of 3 possibilities:</DIV>
<DIV> </DIV>
<DIV>1, Increase the length (lever arm) of the keel bellcrank by=
about 3/8" (would get more travel and more leverage)</DIV>
<DIV>2, Decrease the lever arm of the wing root bell cranks by a=
bout 3/8" would get more travel at the aileron torque tube, but less leverag=
e and therefore stiffer ailerons). This could be done by welding the hole sh=
ut and drilling a new one as hole edge distances could not be maintaine=
d by simply drilling a new hole. </DIV>
<DIV>3, Get cables that have more travel than the 3" the fa=
ctory provides. </DIV>
<DIV> </DIV>
<DIV>So, there is the next chapter in frustration. I will let you know the n=
ext chapter soon. Basically I am no more nuts than I was before, and the lim=
itation is in the system.. not the builder. Whew!! </DIV>
<DIV> </DIV>
<DIV>Kurt Winker</DIV>
<DIV>173 FGE ... flippin flipper fiddelin'</DIV>
<DIV> </DIV>
<DIV> </DIV></BODY></HTML>
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