Just doodles...

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

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

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...


http://www.soaridaho.com/Schreder/Sc...76_Page_28.JPG
http://www.soaridaho.com/Schreder/Sc...76_Page_29.JPG

"cavelamb himself" wrote in message
link.net...
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,

Oops, I didn't intend the send the last message. The "U" joints in the
above referenced article are associated with Dick Schreder's original side
stick design. They have been eliminated in both Bob's and Udo's
modification.

Here are some of the drawings that show the original design containing those
pesky "U" joints.
http://www.soaridaho.com/Schreder/Sc...76_Page_28.JPG
http://www.soaridaho.com/Schreder/Sc...76_Page_29.JPG
http://www.soaridaho.com/Schreder/Sc...76_Page_35.jpg
http://www.soaridaho.com/Schreder/Sc...76_Page_36.jpg

Soaring magazine's entire six month series on building the HP-18 can be
found at
http://www.soaridaho.com/Schreder/Sc...the_HP-18.html

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

Well, hello again.

"That which doesn't kill me - has made a huge tactical mistake".

Not up to 100%, but I'm still kicking and getting my strength back.
Can't believe how long it has taken, but...
No new tumors!


One of the best short sentences in english. Right up there with "It's
benign"

You got that right, Richard.
Ranks right up there with, "Do it again, Stud?".

Glad to have you back!


Split flaps could be included very easily. Again, torque tube spar
that fits over the aileron tube (ala Wittman and Bede?). Wouldn't do
much for adding lift, since they would be so small, but could be helpful
for drag when you need it.

The only caveat that I can think of, and I am certainly not an expert, is
that torque tube actuated flaps can be a bit fragile. The best example I
can think of, as it was stated to me, is the Polywagen--IIRC, the flap
extension speed was fairly low due to the thin torque tube and the tube
could be bent without significant effort on the part of the pilot. I think
that, if I was trying to design a torque tube sistem, I would try to include
a spring to limit the force which could be applied.

Although I don't believe that it was a torque tube system, I believe that
the Vari-EZ used a spring to actuate the speed brake for a similar reason.

Peter

Peter Dohm wrote:

Glad to have you back!


Split flaps could be included very easily. Again, torque tube spar
that fits over the aileron tube (ala Wittman and Bede?). Wouldn't do
much for adding lift, since they would be so small, but could be helpful
for drag when you need it.


The only caveat that I can think of, and I am certainly not an expert, is
that torque tube actuated flaps can be a bit fragile. The best example I
can think of, as it was stated to me, is the Polywagen--IIRC, the flap
extension speed was fairly low due to the thin torque tube and the tube
could be bent without significant effort on the part of the pilot. I think
that, if I was trying to design a torque tube sistem, I would try to include
a spring to limit the force which could be applied.

Although I don't believe that it was a torque tube system, I believe that
the Vari-EZ used a spring to actuate the speed brake for a similar reason.

Peter



Hiya Peter!
Good to hear from you again.
Hope all is well with you and yours.

I'm not very familiar with the Polywagen. I've seen drawings of it,
but never had a chance to study the final product.

My first thought about the spring idea was that it seemed reasonable.
(read it yesterday)

But thinking about it for a while, I'm not so sure.

Two reasons:

First - it's seems it would take _two_ springs.
One to pull it down and one to pull it back up.
The activation force would be the difference between the springs?

Then - the possibility for flirting with flutter.
Springiness in any flight surfaces should be avoided at all costs!
Especially as fast as I'd like this one to go.

My Tailwind used Jim Clement's C model details for the flight controls.

1" x .058 steel torque tube for the aileron drive, with a 1-1/2" .058
6061-T6 "spar tube" centered over that(IIRC). A round spacer at each end
ties the two tubes together and the aileron ribs and skins are pop
riveted to the outer tube.

(Ok, there is a welded steel tube sleeve/spacer at the root end to
tie the tubes together as the torque tube stops at the inboard end
of the aileron. I think I'd just run this one full length).

The flap spar is another piece of 1-1/2" aluminum tube (built similarly)
but actuated via a horn just inside the fuselage.

Very simple, clean and much easier to build than the brazed steel
structure that Steve used. Also has been thoroughly flight proven on
most of the newer Tailwinds.

Well, for what ever it was worth.

It's just a daydream doodle...



Richard

Wayne Paul wrote:


Here are some of the drawings that show the original design containing those
pesky "U" joints.
http://www.soaridaho.com/Schreder/Sc...76_Page_28.JPG
http://www.soaridaho.com/Schreder/Sc...76_Page_29.JPG
http://www.soaridaho.com/Schreder/Sc...76_Page_35.jpg
http://www.soaridaho.com/Schreder/Sc...76_Page_36.jpg

Soaring magazine's entire six month series on building the HP-18 can be
found at
http://www.soaridaho.com/Schreder/Sc...the_HP-18.html

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




Lots of good jucy stuff there.

Thanks for sharing the links, Wayne...


Richard

Hiya Peter!
Good to hear from you again.
Hope all is well with you and yours.

I'm not very familiar with the Polywagen. I've seen drawings of it,
but never had a chance to study the final product.

My first thought about the spring idea was that it seemed reasonable.
(read it yesterday)

But thinking about it for a while, I'm not so sure.

Two reasons:

First - it's seems it would take _two_ springs.
One to pull it down and one to pull it back up.
The activation force would be the difference between the springs?

Then - the possibility for flirting with flutter.
Springiness in any flight surfaces should be avoided at all costs!
Especially as fast as I'd like this one to go.

My Tailwind used Jim Clement's C model details for the flight controls.

1" x .058 steel torque tube for the aileron drive, with a 1-1/2" .058
6061-T6 "spar tube" centered over that(IIRC). A round spacer at each end
ties the two tubes together and the aileron ribs and skins are pop
riveted to the outer tube.

(Ok, there is a welded steel tube sleeve/spacer at the root end to
tie the tubes together as the torque tube stops at the inboard end
of the aileron. I think I'd just run this one full length).

The flap spar is another piece of 1-1/2" aluminum tube (built similarly)
but actuated via a horn just inside the fuselage.

Very simple, clean and much easier to build than the brazed steel
structure that Steve used. Also has been thoroughly flight proven on
most of the newer Tailwinds.

Well, for what ever it was worth.

It's just a daydream doodle...



Richard


I have had a set of plans for the Polywaggen, but currently can not seem to
find them.

Therefore, my recollection is from a construction project that I had an
opportunity to visit. The torque tubes were much smaller in diameter--at
most 3/4" for the flap torque tube. The builder was working on a means to
assure that the system would not fail under flight loads, as he told me that
he had heard of previous problems. I have no recollection of the alloy
used; but a much larger diameter tube, so that damage would be unlikely with
the length of flap handle in use, would certainly solve the problem--and
would probably be lighter and less complex than the spring idea that I have
envisioned.

Peter

Peter Dohm wrote:


I have had a set of plans for the Polywaggen, but currently can not seem to
find them.

Therefore, my recollection is from a construction project that I had an
opportunity to visit. The torque tubes were much smaller in diameter--at
most 3/4" for the flap torque tube. The builder was working on a means to
assure that the system would not fail under flight loads, as he told me that
he had heard of previous problems. I have no recollection of the alloy
used; but a much larger diameter tube, so that damage would be unlikely with
the length of flap handle in use, would certainly solve the problem--and
would probably be lighter and less complex than the spring idea that I have
envisioned.

Peter



Well shoot!

I tried to trun up a link to Jerry Hey's web site, but a lot of the
Tailwind web pages seem to have disappeared.

Jerry is/was(?) offering a kit for the modified Tailwind aileron/flap
system.

Oh well... sorry 'bout that.

Richard