Wayne Paul wrote:

"cavelamb himself" wrote in message
hlink.net...

Wayne Paul wrote:


Bob,

Your HP-18 side-stick to center-stick is an example of good design.
http://www.hpaircraft.com/center_sti...22_january.htm
(Complete story http://www.hpaircraft.com/center_stick/)

Other designs that may be of interest to the group are Udo Rumpf's use of
a PIK-20 sailplane stick
http://www.soaridaho.com/Schreder/Co...ter_Stick.html
and Brian Case's HP-16 modification.

Brian need to lower the seatpan in his HP16 to allow more head/canopy
clearance. So he removed the old cable system which ran under the seat
and designed the following modification:
http://www.soaridaho.com/Schreder/Co..._Stick_Mod.htm
(Brian by his HP-16T
http://www.soaridaho.com/Schreder/HP...Mackay_IDa.JPG)

Wayne
HP-14 "6F"
http://www.soaridaho.com/Schreder



The second picture from the top tells the tale.

I'd assume (?) that there is something like a U joint behind the cockpit
to let the push rod line up with the elevator horn?

I'll have to think about this some more.
You guys just could be right!


Richard,

Here are some pictures from behind the cockpit that may help understanding
Brian's control system..
http://www.soaridaho.com/Schreder/Co...ick_Mod_11.jpg
The above picture was take looking forward. It shows the bulkhead aft of
the wheelwell. You can see the series of bell cranks that actuate the
ailerons and the push the stick's push rod as it is routed through the right
side of the bulkhead. The elevator push rod and direction reversal crank
can be seen on the left side of the bulkhead.

(More pictures
http://www.soaridaho.com/Schreder/Co...tick_Mod_9.jpg
http://www.soaridaho.com/Schreder/Co...ick_Mod_10.jpg)

As you can see, there are no "U-joints". The linkage has almost no "slop"
and give good control surface feed-back.

It should also be noted that the ailerons droop and reflex with the flaps
avoiding misalignment during normal cruise and thermaling flap
configurations.

Wayne
HP-14 "6F
http://www.soaridaho.com/Schreder



Richard



Sorry. my bad.
I was refering to the U-Joint in the Elevator pushrods.
(and a word of warning about them...)
http://www.soaridaho.com/Schreder/Co...ll.html#ujoint

That lateral torque tube (actually a walking beam) in my sketch is in
the elevator control system. It takes the pushrod from the lateral
joystick torque tube and inverts it so the long tube to the elevator
is in tension. Also centers up the aft push pull tube.

The lower arm in the center is the attach horn for a MAC servo (elevator
trim) coupled by a "U" shaped fiberglass spring. I didn't dream that
one up - saw it on the net some years back - but I wish I had.

Well, _I_ thought it was a pretty simple setup...

Richard