Today's Message Index:
----------------------
1. 06:42 AM - Rib-testing (Gary W Meadows)
2. 08:24 AM - Throttle quadrant plans (Andimaxd@aol.com)
3. 09:37 AM - Re: Throttle quadrant plans (Isablcorky@aol.com)
4. 10:00 AM - Re: Rib-testing (Ed G.)
5. 10:11 AM - Re: Throttle quadrant plans (Phillips, Jack)
6. 03:30 PM - Re: Rib-testing (Isablcorky@aol.com)
Message 1
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Hey guys,
It's been a while since I posted, but I just wanted to exit lurking mode and chime
in on my highly unscientific version of rib-testing. I made up a test rib,
and let it cure for a few days. Next, I propped the rib up between the workbench
and my step stool. I then lifted myself up on my hands holding onto the bench
and ladder and placed one foot onto the rib. I gradually let the rib take
my weight until I had probably 70 - 80% of my weight on that rib!! Now, I'm about
230 on the hoof, so I figure that rib was holding up a ballpark of between
160 to 185 pounds!!! I was amazed at how strong those things are!! Anyway, I
then did the math - 30 ribs * 170# and came up with around 5000# - good enough
for me!! Even if I guessed way wrong, that rib was still holding an incredible
amount of weight when compared to how much IT weighs. Kinda like an ant!!
To do a more accurate test, I guess I could have place the rib on a board on a
bathroom scale, but all it was for was to bolster my confidence in the rib design,
material and my own building technique and it worked!!!
By the way, I made one rib per night and let the one side cure, then the next
day, glued on the opposite side gussetts and made a new on in the jig. It was
slow, but I was working tail feathers too, so it was fine. I also had trouble
with the ribs not holding their shape out of the jig. I suspect my capstrip bending
wasn't thourough enough.
Now, I'll go back into stealth mode and get back to work, waiting to get home
and into the garage to get back to work on the Piet!!
Gary Meadows
Spring, TX
Message 2
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| Subject: | Throttle quadrant plans |
Hello to all in the group:
Does anyone have plans for a throttle quadrant like these? I don't
want/need anything fancy. I can build one from scratch from these pictures, but,
I
don't know how long to make the "throw & pivot points". These two examples
seem to be very different in their geometry. I don't know what would be best
with a continental 75 engine/carburetor.
This is just a shot in the dark, but I thought I would ask anyhow.
Thanks in advance, and happy building/flying,
Max Davis
Arlington, TX.
NX101XW (We now have an official N number, very exciting!)
(http://mykitplane.com/Planes/photoDisplay.cfm?PhotoName=DSCF0007a.JPG&PhotoID=2291)
Message 3
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| Subject: | Re: Throttle quadrant plans |
Max,
I remember a comment by my DAR. He said to make the throw on the quad larger
than the needed movement of the throttle arm.
Corky who can't remember too much lately
Message 4
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--> Pietenpol-List message posted by: "Ed G." <flyboy_120@hotmail.com>
Good to see you back on the list Gary...It has been a long time..I made my
ribs the same way, let the top gussets cure overnight then pulled the rib
out of the jig and put the gussetts on the flip side and do the first side
of a new rib each day. They came out great and there is no detectable
difference between any of them.I lined my rib jig with plastic grocery bags
cut down each side..They protected the rib jig and most of the plastic would
peel off the T-88..the rest I just sanded off .. I would lay up a rib then
go work on some other part of my Piet...If you're patient it works
great...Ed G.
>From: Gary W Meadows <garymead@swbell.net>
>Reply-To: pietenpol-list@matronics.com
>To: pietenpol-list@matronics.com
>Subject: Pietenpol-List: Rib-testing
>Date: Mon, 28 Feb 2005 06:41:56 -0800 (PST)
>
>Hey guys,
>
> It's been a while since I posted, but I just wanted to exit lurking mode
>and chime in on my highly unscientific version of rib-testing. I made up a
>test rib, and let it cure for a few days. Next, I propped the rib up
>between the workbench and my step stool. I then lifted myself up on my
>hands holding onto the bench and ladder and placed one foot onto the rib. I
>gradually let the rib take my weight until I had probably 70 - 80% of my
>weight on that rib!! Now, I'm about 230 on the hoof, so I figure that rib
>was holding up a ballpark of between 160 to 185 pounds!!! I was amazed at
>how strong those things are!! Anyway, I then did the math - 30 ribs * 170#
>and came up with around 5000# - good enough for me!! Even if I guessed way
>wrong, that rib was still holding an incredible amount of weight when
>compared to how much IT weighs. Kinda like an ant!!
>
> To do a more accurate test, I guess I could have place the rib on a board
>on a bathroom scale, but all it was for was to bolster my confidence in the
>rib design, material and my own building technique and it worked!!!
>
> By the way, I made one rib per night and let the one side cure, then the
>next day, glued on the opposite side gussetts and made a new on in the jig.
>It was slow, but I was working tail feathers too, so it was fine. I also
>had trouble with the ribs not holding their shape out of the jig. I suspect
>my capstrip bending wasn't thourough enough.
>
> Now, I'll go back into stealth mode and get back to work, waiting to get
>home and into the garage to get back to work on the Piet!!
>
> Gary Meadows
> Spring, TX
Message 5
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| Subject: | Throttle quadrant plans |
I=A1=AFll look tonight and thry to make some measurements off mine. I have an
A65 Continental.
It=A1=AFs basic geometry to design your own. You need to know the circmferential
distance you need the cable to provide at the carburetor. Measure the distance
from the pivot point of the thrrottle arm on the carb to the point where
your bugnut will be attached (call this dimentions =A1=B0r=A1=B1 for radius.
Now measure the number of degrees the throttle arm needs to move to go from idle
stop to full throttle (use your kid=A1=AFs elementary school protracter).
Now divide this number (it=A1=AFll be somewhere around 45 =A2=AA) by 57.30 to
convert it to radians (don=A1=AFt worry about what that means, just do it) and
multiply that number by what you got for =A1=B0r=A1=B1 above. This is the linear
distance the throttle cable needs to provide.
Now for the cockpit end. Your throttle quadrant needs to produce this amount of
linear travel, plus a little bit more, as Corky so wisely suggested. The reason
for this is to make the stops at the carburetor, not in your quadrant. Otherwise
you will not be able to quite get full throttle (increases pucker factor
on takeoff) or quite get down to idle (which can cause some high speed taxiing,
especially downhill and downwind).
Here you=A1=AFve got a little discretion. I suggest you go sit in some other airplanes
and see how they feel, then measure their quadrants. I copied mine from
a J-3 Cub, because I used to own one and thought its throttle felt fine.
You=A1=AFve got two paraemters you can play with - the radius (length) of your
throttle lever, and its throw, or angular sweep. The longer the radius, the
less angle it needs to sweep through to get the same cable movement. The formula
is Radius x Angle (in degrees, divided by 57.30 to convert to radians) linear
cable movement, which should be maybe =A8=F9=A1=B1 more than the cable movement
required by the carburetor. As to how long to make your throttle quadrant
lever, that is a matter of personal preference. Obviously, it needs to be
at least as long as the Radius you just determined, but how much longer is up
to you.
One other thing to watch out for - your cable needs to be solidly attached to structure
near the attach points for both the quadrant and the carburetor. Otherwise,
some of your quadrant movement will just go into bending the entire cable,
housing and all.
Good luck,
Jack
Still working to repair NX899JP in time to fly it to Brodhead this summer
-----Original Message-----
Does anyone have plans for a throttle quadrant like these? I don't want/need anything
fancy. I can build one from scratch from these pictures, but, I don't
know how long to make the "throw & pivot points". These two examples seem to
be very different in their geometry. I don't know what would be best with a
continental 75 engine/carburetor.
This is just a shot in the dark, but I thought I would ask anyhow.
Thanks in advance, and happy building/flying,
Max Davis
Message 6
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Gary,
Sure good to hear from you again. Stop in when you can
Corky and Isabelle
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