Texas Parasol

On Aug 14, 2:53 pm, Fred the Red Shirt
wrote:
...
I do see a problem with the forward carry-thru as dimensioned on
drawing DLG03 Landing Gear and Lift Strut Carry-Throughs

There are two (2) different holes called out as 2 1/8" from the
end of the carry-through. One of those is for attaching the
forward gear leg to the follow-though, the other is for attaching
the follow-through to the fuselage. However, since the fuselage
is only 22" wide and the follow-through is 26" long that puts
the center of that hole only 1/8" from the outside edge of the
fuselage.

I think THAT dimension is wrong. It appears to be the CAD
equivalent of a typo. I suggest it should be 2 3/8". Please
check that.

Oh, the manual (p 49) suggests drilling through the longerons
first and then drilling the follow-through to match. That works,
right?

...

... I suppose
the builder would have to figure out for himself to hold
the tubing in its proper orientation while welding, (Or
is that addressed in the manual?)

Indeed, that is addressed in the manual, though it looks
to sort of gloss over the question of how you check to see
that the axles are going to be aligned properly.

--

FF

Fred the Red Shirt wrote:

Well I'm not Clare, nor do I see anything that would prevent the wing
from fitting, but I haven't looked for problems there either.

I do see a problem with the forward carry-thru as dimensioned on
drawing DLG03 Landing Gear and Lift Strut Carry-Throughs

There are two (2) different holes called out as 2 1/8" from the
end of the carry-through. One of those is for attaching the
forward gear leg to the follow-though, the other is for attaching
the follow-through to the fuselage. However, since the fuselage
is only 22" wide and the follow-through is 26" long that puts
the center of that hole only 1/8" from the outside edge of the
fuselage.

I think THAT dimension is wrong. It appears to be the CAD
equivalent of a typo. I suggest it should be 2 3/8". Please
check that.

If you go to the Yahoo Texas Parasol Group and look at the first
photo of Jim's TP in the photos section you will see that the bolt
attaching the carry-though is indeed inboard of the bolt attaching
the gear.

Perhaps I am overly optimistic but I don't think the situation
is as dire as Mr Hoover indicated It looks to me that all that
is needed to to properly locate the hole for attaching the
carry-throughs to the fuselage and then maybe bend the
angles of one follow-through slightly away from 90 degrees
to compensate for the curvature of the lower longeron.

Then it looks like everything will fit together, I don't know
about edge clearances though.

As for the lower gear cluster weldment, I agree that the
drawings, like every homebuilt aircraft drawings i have
seen, are inadequate as compared to REAL weldment
drawings (e.g. no weld symbols are shown). I suppose
the builder would have to figure out for himself to hold
the tubing in its proper orientation while welding, (Or
is that addressed in the manual?)

--

FF



Thanks Fred.
That detail is called out on page 48 of the manual.
But I'll note it on this drawing.
Maybe it will make my loyal opposition happy...


There is a photo essay on "how to" clusters
http://groups.yahoo.com/group/texasp...anding%20Gear/


--

Richard

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Fred the Red Shirt wrote:

Indeed, that is addressed in the manual, though it looks
to sort of gloss over the question of how you check to see
that the axles are going to be aligned properly.

--

FF


Good Grief Please Don't Open That Can Of Worms!


More bandwith has been expended over the Toe-In verses Toe-Out
argument than any other idea on the internet!


Me? I make them as straight as I can.

Cut a piece of water pipe (left over from the clusters) to fit
between the axle clusters and run the bolts in from the outside.

Drill it, bolt it, and call it close enough!

--

Richard

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On Aug 14, 5:35 pm, cavelamb himself wrote:
Fred the Red Shirt wrote:

...

Thanks Fred.
That detail is called out on page 48 of the manual.
But I'll note it on this drawing.
Maybe it will make my loyal opposition happy...

Now, to all parties involved in the prior ****ing contest,
"Wasn;t that easy?"

Or, as Andy Bray says he

http://www.youtube.com/watch?v=2YmEiGgwnBI

--

FF

Fred the Red Shirt wrote:
On Aug 14, 5:35 pm, cavelamb himself wrote:

Fred the Red Shirt wrote:

...

Thanks Fred.
That detail is called out on page 48 of the manual.
But I'll note it on this drawing.
Maybe it will make my loyal opposition happy...


Now, to all parties involved in the prior ****ing contest,
"Wasn;t that easy?"

Or, as Andy Bray says he

http://www.youtube.com/watch?v=2YmEiGgwnBI

--

FF


Awright, smartie.

Now go build something!

--

Richard

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On Aug 15, 1:48 am, cavelamb himself wrote:
Fred the Red Shirt wrote:



On Aug 14, 5:35 pm, cavelamb himself wrote:

Fred the Red Shirt wrote:

...

Thanks Fred.
That detail is called out on page 48 of the manual.
But I'll note it on this drawing.
Maybe it will make my loyal opposition happy...

Now, to all parties involved in the prior ****ing contest,
"Wasn;t that easy?"

Or, as Andy Bray says he

http://www.youtube.com/watch?v=2YmEiGgwnBI

--

FF

Awright, smartie.

Now go build something!


But I'm not done yet, and so long as I have you in a good mood
I figure I might as well press my luck.

Now, I don't see a vertical dimension locating the holes in the carry-
throughs
for the bolts about which the landing gear legs pivot. But there
isn't a lot
to play with, right?

Here is where it gets interesting. The lower longerons are curved.
That
means if those holes are drilled the same for the front and back
longeron
the axes about which those legs pivot will not be colinear, nor even
parallel. I do not agree that it makes the plane unbuildable. After
all,
there are several photos that show the gear built just like it says
in
the manual.

But that does mean that if the fuselage were infinitely stiff, the
legs
would not pivot and the gear would not flex. I presume the gear does
flex, else landings would be a bit hard on the butt as well as the
plane.

So what DOES flex and how, the lower longeron, the carry-thoughs or
both? Also how, and how much and is that a good idea? (Being light
weight construction, even if those bolts were coaxial there would be
flexure at the attachment point.) Now, if you forgive me for again
raising
a much cussed and discussed issue, that also implies that as the gear
flexes the toe-in, toe-out with change, whether for better or worse is
yet
another interesting question.

So long as the subject is the Texas Parasol, are these matters worth
discussing?

--

FF

Fred the Red Shirt wrote:
On Aug 15, 1:48 am, cavelamb himself wrote:

Fred the Red Shirt wrote:




On Aug 14, 5:35 pm, cavelamb himself wrote:

Fred the Red Shirt wrote:

...

Thanks Fred.
That detail is called out on page 48 of the manual.
But I'll note it on this drawing.
Maybe it will make my loyal opposition happy...

Now, to all parties involved in the prior ****ing contest,
"Wasn;t that easy?"

Or, as Andy Bray says he

http://www.youtube.com/watch?v=2YmEiGgwnBI

--

FF

Awright, smartie.

Now go build something!



But I'm not done yet, and so long as I have you in a good mood
I figure I might as well press my luck.

Now, I don't see a vertical dimension locating the holes in the carry-
throughs
for the bolts about which the landing gear legs pivot. But there
isn't a lot
to play with, right?

Here is where it gets interesting. The lower longerons are curved.
That
means if those holes are drilled the same for the front and back
longeron
the axes about which those legs pivot will not be colinear, nor even
parallel. I do not agree that it makes the plane unbuildable. After
all,
there are several photos that show the gear built just like it says
in
the manual.

But that does mean that if the fuselage were infinitely stiff, the
legs
would not pivot and the gear would not flex. I presume the gear does
flex, else landings would be a bit hard on the butt as well as the
plane.

So what DOES flex and how, the lower longeron, the carry-thoughs or
both? Also how, and how much and is that a good idea? (Being light
weight construction, even if those bolts were coaxial there would be
flexure at the attachment point.) Now, if you forgive me for again
raising
a much cussed and discussed issue, that also implies that as the gear
flexes the toe-in, toe-out with change, whether for better or worse is
yet
another interesting question.

So long as the subject is the Texas Parasol, are these matters worth
discussing?

--

FF


First - you would be surprised how rigid the airframe is.

Sure, all trusses flex. But if you expect this one to flex like a
pop riveted aluminum tube structure you will for sure and certain be
amazed. It doesn't flex at all like you are describing. It flexes
a lot more like a welded 4130 tube structure.

I guess I don't follow why there would have to be flexure in the
structure for the gear to move freely. The gear legs piviot on the
bolts. And, BTW, how far is the gear going to move anyway?

I don't know about any changes in toe-in/toe-out changes with gear
movement. Maybe it does, maybe it doesn't. I've never had a reason
to worry about it. My airplanes all tracked straight.



KISS.

It's real important.


--

Richard

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On Aug 17, 10:17 pm, cavelamb himself wrote:

...

First - you would be surprised how rigid the airframe is.

...

I guess I don't follow why there would have to be flexure in the
structure for the gear to move freely. The gear legs piviot on the
bolts. And, BTW, how far is the gear going to move anyway?

In reverse order, it must move, else the bungies would serve
no purpose.

Now, imagine two bars arranged in a Vee. Pin the two ends
to a flat surface and pin the two bars together at the apex, but
do not pin the apex it to the surface. The Vee is rigid. Neither
bar is free to pivot about the end pinned to the table.

Now, move the two ends pinned to the table so that they
overlap and pin both to the table t that point. Now they
pivot because the pins are coaxial.

The TP landing gear is a 3-D version of exactly that
situation.

The effect is clear. The magnitude is what makes it
important or not.


I don't know about any changes in toe-in/toe-out changes with gear
movement. Maybe it does, maybe it doesn't. I've never had a reason
to worry about it. My airplanes all tracked straight.


And I suppose that means the flexure in the airframe is real
small. It would be interesting if someone building a TP were
to look carefully at it while the fuselage is inverted.

KISS

Yes, that is what is very attractive about the TP. It has one
of the shortest build times of the scratch-builts, less than
many kitplanes, and relies on simple technique.

--

FF

On Aug 17, 5:27*pm, Fred the Red Shirt

...Here is where it gets interesting. *The lower longerons
are curved. That means if those holes are drilled the
same for the front and back longeron the axes about
which those legs pivot will not be colinear, nor even
parallel...

Non-Euclidean geometry aside, that seems to me to be a rather sub-
optimal design approach. Nothing that a couple of rod ends or rubber
bushings couldn't fix. But it would probably be lighter and more
effective to just make the gear leg holes colinear, and then build,
adjust, or drill the fuselage to maintain that colinearity.

Bob Kuykendall wrote:
On Aug 17, 5:27 pm, Fred the Red Shirt

...Here is where it gets interesting. The lower longerons
are curved. That means if those holes are drilled the
same for the front and back longeron the axes about
which those legs pivot will not be colinear, nor even
parallel...


Non-Euclidean geometry aside, that seems to me to be a rather sub-
optimal design approach. Nothing that a couple of rod ends or rubber
bushings couldn't fix. But it would probably be lighter and more
effective to just make the gear leg holes colinear, and then build,
adjust, or drill the fuselage to maintain that colinearity.


Which is the way it is done...

--

Richard

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