Just doodles...

[cavelamb himself]

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! :)

Only problem now is boredom!
A person can only watch TV for so long before his brains liquefy.

I've dusted off the sketches of the low wing design study and
worked on them up a bit. It seems to be coming along nicely.

All the fuselage bulkhead patterns are finally done.
Wraps up pretty nice.

While it could be powered with a VW (1835 or 2180), I'd love
to hang a Rotax 914 (turbo version) on it with an electric
prop and the long wing option (with 30 gallons of gas?).
And a relief tube!


http://www.home.earthlink.net/~cavelamb/l-one.htm


Richard

[Steve Foley]

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


> I've dusted off the sketches of the low wing design study and
> worked on them up a bit. It seems to be coming along nicely.
>
> All the fuselage bulkhead patterns are finally done.
> Wraps up pretty nice.

>
> http://www.home.earthlink.net/~cavelamb/l-one.htm
>

Why not directly connect the elevator control linkage to the bottom of the
elevator instead of using that movement reversing thingy (blue moving part)?

I hate moving parts (can you tell?)

[cavelamb himself]

Steve Foley wrote:
> "cavelamb himself" > wrote in message
> link.net...
>
>
>
>>I've dusted off the sketches of the low wing design study and
>>worked on them up a bit. It seems to be coming along nicely.
>>
>>All the fuselage bulkhead patterns are finally done.
>>Wraps up pretty nice.
>
>
>>http://www.home.earthlink.net/~cavelamb/l-one.htm
>>
>
>
> Why not directly connect the elevator control linkage to the bottom of the
> elevator instead of using that movement reversing thingy (blue moving part)?
>
> I hate moving parts (can you tell?)
>
>

Hi Steve,

See the side view x-ray sketch.

It's a pretty small ship. A bit larger than a Hummelbird, but still
smaller than a Midget Mustang.

There isn't much (any?) room under the seat!

For what it's worth...
Some people might enjoy a steel tube push rod running through their
butt, but I thought it would be more comfortable to pass it along the
side of the seat instead. :)

Another point is to keep the long slender pushrod in the aft fuselage
in tension (for postive G loads) rather than compression.


This morning I took out the extra break in the side longeron (frame 2).
It's now a straight shot from the firewall to frame 3.
See w12-04x6 and w12-05x9.
Should make it a little simpler to build.
Maybe?

The skins will still have to be sectioned up there because of the
shape of the bottom curves. I never was happy with a break in the
side skins right at the wing Center of Pressure point.

That change ought so smooth out the cross section plot a bit too.

It's all compromise, you know.


Richard

[Bob Kuykendall]

Some random notes about the stick mechanism from my experience building
and installing a retrofit cockpit control stich mechanism:

* The way the two aileron bellcranks are located below the axis of the
stick's pitch pivot, there will be rather a lot of unintended mixing of
pitch input into the ailerons. The usual way of avoiding that is to
place one or both ends of each transverse aileron PP tube near the
pitch pivot axis. They don't have to be right on the axis, just close.

* That other poster is right, the blue reversal bellcrank behind the
seat is probably something you can do without. Parts you leave on the
ground can't break in the air.

* If you want to see some really elegant ways of implementing control
sticks where you can't fit anything under the seat pan, have a look at
a European sailplane.

Bob K.
http://www.hpaircraft.com

[cavelamb himself]

Richard Riley wrote:
> On Fri, 19 Jan 2007 07:30:58 GMT, cavelamb himself
> > wrote:
>
>
>>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?".

>>Only problem now is boredom!
>>A person can only watch TV for so long before his brains liquefy.
>>
>>I've dusted off the sketches of the low wing design study and
>>worked on them up a bit. It seems to be coming along nicely.
>
>
> I know it's just a sketch, but you're going to want some kind of
> aileron differential for adverse yaw. Hinging them at the upper
> surface is probably plenty.

Agreed, again.

Using a torque tube for the ailerons would place the rotation point
at the center of the tube. Simple hangErs mounted on the aft spar.

But playing around with the shape of the bellcranks should work out
as well. The outboard arms could angle forward a few degrees.
There is plenty of room for that as the total travel is small.
They poke thru the fuselage skin into the wing root.

While it doesn't show on the elevator animation (lazy) it looks like
there is probaby some aileron/elevator interaction. Tie the inboard end
of the pushrods to the back side of the stick horn and the ailerons
will deflect down a couple of degrees with aft stick and reflex up a
couple with forward stick.

I decided to keep the aileron mechanism out of the wing in order to
seal up a few ribs for an optional wet wing. The nose tank only holds
about 8 gallons. So maybe 6 to 11 gallons in each wing? Looks do-able.

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.

For the VW sport version I don't think I'd bother.
Keep it light and simple.

I know it's just a sketch, but if I ever decide to take on another
project, this will probably be the one.

It shouldn't cost more than about 5K with an 1835 VW.
Anybody want to buy a Vulcan?


Richard

[Wayne Paul]

Bob,

Your HP-18 side-stick to center-stick is an example of good design.
http://www.hpaircraft.com/center_stick/update_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/Construction/SHP-18_Center_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/Construction/HP-16_Stick_Mod/HP-16_Stick_Mod.htm
(Brian by his HP-16T
http://www.soaridaho.com/Schreder/HP-16/N16VP/N16VP_Mackay_IDa.JPG)

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




"Bob Kuykendall" > wrote in message
oups.com...
> Some random notes about the stick mechanism from my experience building
> and installing a retrofit cockpit control stich mechanism:
>
> * The way the two aileron bellcranks are located below the axis of the
> stick's pitch pivot, there will be rather a lot of unintended mixing of
> pitch input into the ailerons. The usual way of avoiding that is to
> place one or both ends of each transverse aileron PP tube near the
> pitch pivot axis. They don't have to be right on the axis, just close.
>
> * That other poster is right, the blue reversal bellcrank behind the
> seat is probably something you can do without. Parts you leave on the
> ground can't break in the air.
>
> * If you want to see some really elegant ways of implementing control
> sticks where you can't fit anything under the seat pan, have a look at
> a European sailplane.
>
> Bob K.
> http://www.hpaircraft.com
>

[cavelamb himself]

Bob Kuykendall wrote:

> Some random notes about the stick mechanism from my experience building
> and installing a retrofit cockpit control stich mechanism:
>
> * The way the two aileron bellcranks are located below the axis of the
> stick's pitch pivot, there will be rather a lot of unintended mixing of
> pitch input into the ailerons. The usual way of avoiding that is to
> place one or both ends of each transverse aileron PP tube near the
> pitch pivot axis. They don't have to be right on the axis, just close.
>
> * That other poster is right, the blue reversal bellcrank behind the
> seat is probably something you can do without. Parts you leave on the
> ground can't break in the air.
>
> * If you want to see some really elegant ways of implementing control
> sticks where you can't fit anything under the seat pan, have a look at
> a European sailplane.
>
> Bob K.
> http://www.hpaircraft.com
>

Man, Bob, that thing is some kinda slick!
You do really nice work!

It took a while to find the details of the center stick setup.
If you don't mind, here are some links for the gang.

First pics I located.
http://www.hpaircraft.com/center_stick/update_9_april.htm

Now I see what you mean.
Small U joints in the PP tube allows for some angular offset.
You have the advantage here with a Looong tail.
Small angular offset.

Some more pics of the stick and mechanism here...
http://www.hpaircraft.com/center_stick/update_22_january.htm
http://www.hpaircraft.com/center_stick/update_9_october.htm

Aileron (roll) bellcranks - in DOUBLE shear!
http://www.hpaircraft.com/center_stick/18-704,18-705.pdf

I built some kinda sorta like this once, but with joggled
arms. The spacer approach makes a lot more sense. And more
accurately reproducible too.

But then I found this one...
http://www.hpaircraft.com/hp-24/update_23_November_05.htm
the DISadvantage of that Looong tail...

92% done - 80% to go???


Richard

[cavelamb himself]

Wayne Paul wrote:

> Bob,
>
> Your HP-18 side-stick to center-stick is an example of good design.
> http://www.hpaircraft.com/center_stick/update_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/Construction/SHP-18_Center_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/Construction/HP-16_Stick_Mod/HP-16_Stick_Mod.htm
> (Brian by his HP-16T
> http://www.soaridaho.com/Schreder/HP-16/N16VP/N16VP_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

[Bob Kuykendall]

Earlier, cavelamb himself wrote:

> ...But then I found this one...
> http://www.hpaircraft.com/hp-24/update_23_November_05.htm
> the DISadvantage of that Looong tail...
>
> 92% done - 80% to go???

Yup, something like that!

Funny you should mention those pictures. This weekend I'm going up to
Seattle (Monroe, actually, out beyond Arlington) to help Brad Hill
build the equivalent tooling to locate the elevator PP tube in his
Glidair motorglider fuselage.

Here's the latest Glidair update at my Web site:

http://www.hpaircraft.com/glidair/update_17_january_07.htm

These pages show us making and installing the elevator PP tube guides
in the HP-24 fuselage:

http://www.hpaircraft.com/hp-24/update_18_January_06.htm

http://www.hpaircraft.com/hp-24/update_23_January_06.htm

The guides themselves are copies of a standard ACS part - which is a
copy of a standard Rolladen-Schneider part. They're about $10 ea from
ACS. They have an ID of 5/8", which makes for a reasonable light-duty
PP tube in .035" wall 6061-T6.

Thanks, and best regards to all!

Bob K.
http://www.hpaircraft.com

[Wayne Paul]

"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_stick/update_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/Construction/SHP-18_Center_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/Construction/HP-16_Stick_Mod/HP-16_Stick_Mod.htm
>> (Brian by his HP-16T
>> http://www.soaridaho.com/Schreder/HP-16/N16VP/N16VP_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/Construction//HP-16_Stick_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/Construction//HP-16_Stick_Mod_9.jpg
http://www.soaridaho.com/Schreder/Construction//HP-16_Stick_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

[cavelamb himself]

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_stick/update_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/Construction/SHP-18_Center_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/Construction/HP-16_Stick_Mod/HP-16_Stick_Mod.htm
>>>(Brian by his HP-16T
>>>http://www.soaridaho.com/Schreder/HP-16/N16VP/N16VP_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/Construction//HP-16_Stick_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/Construction//HP-16_Stick_Mod_9.jpg
> http://www.soaridaho.com/Schreder/Construction//HP-16_Stick_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/Construction/HBldr_Hall.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

[Wayne Paul]

"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/Construction//HP-16_Stick_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/Construction//HP-16_Stick_Mod_9.jpg
>> http://www.soaridaho.com/Schreder/Construction//HP-16_Stick_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/Construction/HBldr_Hall.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/Schreder/Soaring_July_1976_Page_28.JPG
http://www.soaridaho.com/Schreder/Schreder/Soaring_July_1976_Page_29.JPG

[Wayne Paul]

"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_stick/update_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/Construction/SHP-18_Center_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/Construction/HP-16_Stick_Mod/HP-16_Stick_Mod.htm
>>>>(Brian by his HP-16T
>>>>http://www.soaridaho.com/Schreder/HP-16/N16VP/N16VP_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/Construction//HP-16_Stick_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/Construction//HP-16_Stick_Mod_9.jpg
>> http://www.soaridaho.com/Schreder/Construction//HP-16_Stick_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/Construction/HBldr_Hall.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/Schreder/Soaring_July_1976_Page_28.JPG
http://www.soaridaho.com/Schreder/Schreder/Soaring_July_1976_Page_29.JPG
http://www.soaridaho.com/Schreder/Schreder/Soaring_Aug_1976_Page_35.jpg
http://www.soaridaho.com/Schreder/Schreder/Soaring_Aug_1976_Page_36.jpg

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

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

[Peter Dohm]

> >>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

[cavelamb himself]

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

[cavelamb himself]

Wayne Paul wrote:


> Here are some of the drawings that show the original design containing those
> pesky "U" joints.
> http://www.soaridaho.com/Schreder/Schreder/Soaring_July_1976_Page_28.JPG
> http://www.soaridaho.com/Schreder/Schreder/Soaring_July_1976_Page_29.JPG
> http://www.soaridaho.com/Schreder/Schreder/Soaring_Aug_1976_Page_35.jpg
> http://www.soaridaho.com/Schreder/Schreder/Soaring_Aug_1976_Page_36.jpg
>
> Soaring magazine's entire six month series on building the HP-18 can be
> found at
> http://www.soaridaho.com/Schreder/Schreder/Building_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

[Peter Dohm]

> 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

[cavelamb himself]

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