Texas Parasol Plans...

On Sat, 18 Feb 2006 06:35:38 GMT, Richard Lamb
wrote:

clare at snyder.on.ca wrote:


And just to make things clear, I don't have a pony in this race.
I did not buy plans. I did not invest ANY time or money in the
project, and there was no reason for my Friend Gary to say anything
negative about the plane EXCEPT the fact he is VERY dedicated to SAFE
flying. He, and a lot of the other fellows, were hoping it would be a
good, cheap plane, and easy to build and fly. The building method is
VERY interesting, but to get proper hole edge clearances the longerons
in the cabin area should be 1" angle.
If built "inside out" with the flats of the angles in, instead of out,
you would not have issues with the fabric at the rivet heads, and you
would also have a smoother interior. Lots of other little
"improvements" that would make it a better plane - .

Really just needs a good designer to go ever it and fix the little
details - the ones that make the current rendition difficult to build
and less than adequate structurally. As they say, the devil's inthe
details - and they will kill you.

Your loyalty to your friend is noted and admired, Clare.

But for just a moment, stop and reread what you wrote above.
Sure, the inside-out approach has some interesting merit, but is that
really and improvement, a radical modification, or a new design?

The first step in designing something like an airplane is
to carefully define the (dreaded) Mission Requirements Statement.

This one, as it is, fulfills the mission requirements set out for it.
And it has done so safely for many years.

As far as I could tell from the photos and article published in the Canadian
Recreational Aviation magazine the only thing the Canadian projects have in
common with this one is that they both use extruded aluminum angle for the
fuselage truss.

Richerd,
You are getting ahead of yourself.
Forget the pictures you saw in the Rec Av magazine. Those were
projects some guys built. They were NOT the tests done by Gary. Gary
did the tests on a wing BUILT ACCORDING TO PLANS, and IT FAILED THE
TEST.

The other improvements I noted should/could be made HAVE NEVER BEEN
IMPLEMENTED to the best of my knowledge.

As for the extruded aluminum truss construction, using the sizes
listed in the plans, and the rivets specified, it is difficult, if not
impossible, to achieve proper hole edge clearances in MANY locations.
I know, for an ultralight there are no inspections, so you can get
away with it - but you are NOT building to acceptable aircraft
standards if proper edge clearances can not be maintained.

You can claim these were only improvements if you want.
But what it really was is a completely new, unproved, and much heavier
machine. (I'm curious why they didn't go to a 2-1/4" front spar as we
discussed repeatedly. I know it an expensive piece of tube, but it would
have solved the problem quite adequately.)

Then put the D@%&D thing in the plans, already.


My friend, Al Robinson is doing exactly the same thing! But man, what a
difference in attitudes.

His Texas Pete is a two-seat side by side with a Geo Metro of power.
Gross weight will be right about 900 pounds.
(His pics and details are posted on the Texas Parasol group at Yahoo Groups)
(as are reports of some of those who finished and have flown their (real)
Texas Parasols)


The Texas Parasol is just an angle aluminum Baby Ace in concept -
shortened and with bigger tailfeathers to compensate.
Apparently you built yours one station longer, making it the same
dimensions as the Ace. The wings are the same dimensions and planform
as well, from what I understand. So the CONCEPT is a good one.
The plane CAN be built as a safe, economical, fun-to-fly plane - but
NOT as per plans.
Fix the inadequacies (which means admitting to them first) and make
the plans accurate enough to build from, and you'll have all kinds of
support.
The modifications he has made to the wing structure were supervised and
blessed by none other than the late Lt. Graham Lee. I don't think Graham
had a degree, but he was one hell of an engineer.

Then document the modifications and put them in the plans.

Al is getting close to being ready to static test his wing - and I intend to
be there to help when he does. He kindly invited me, and I wouldn't miss is.
If it holds ok, we'll cover it and go flying.

If it doesn't look safe to BOTH of us, we'll come up with something else.
Most likely (if necessary!) an I beam main spar built up using extruded
aluminum angle front and back of an aluminum sheer web.
At least that's our fall back plan.
That type construction allows us to custom tailor the load factor allowance
to what ever the builder desires.

I've got the thing drawn up, but I've not built it and tested it yet, so
it hasn't been published. And it's not going to be unless it IS tested.

That sounds like a good idea.

I have personally flown both of my parasols (well duh!) and several of the
others.

But tell everyone how you built yours. It was not strictly to plans.
What about the leave in the spar??

Doc has flown damned near all of them and scared the pee outta me several
times in the process.

Sonny is building his FOURTH original design based on this stuff.

Paul Hammond flew his every weekend for years.

Doc is home taking care of the kids.

I'm sitting here trying to be patient and not pull my hair out.


So if is possible, can we call a truce and go make fun of milli-amp
for a while?

A FULL truce is as close as the corrections to the plans. Just because
nobody's killed themselves YET does not mean the plans, as they exist
today, are safe. By your admission, many builders ARE making changes.

Richard

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wrote

The dry weight of the prototype was 200 lbs and it was designed
for 400 lbs gross, by real engineers.

I could not fly it, and I'm by no means, a lard butt. Under 170 lbs for
the pilot, it looks like to me.
--
Jim in NC

clare at snyder.on.ca wrote:

Clare, thanks for taking a reasonable position and tone.
Muchly appreciated.
I'll reply as best I can, ok?

Richerd,
You are getting ahead of yourself.
Forget the pictures you saw in the Rec Av magazine. Those were
projects some guys built. They were NOT the tests done by Gary. Gary
did the tests on a wing BUILT ACCORDING TO PLANS, and IT FAILED THE
TEST.

That was not my take from the article, but if I'm wrong on that point,
I'll offer an apology.

The Test:

I've never been offered any description of the set up - only the conclusions.

As I understand it, it was assumed that the front spar would take 100% of the
load. That is, of course, true IF the spar is located at the center of
pressure - as a normal wing is arranged.

But the wing in question is obviously NOT arranged that way.
The spars are at the leading and trailing edges while the center of pressure
remains back around 30% to 40% of the chord.

The airfoil used is a Clark-Y. There is a minor deviation at the leading edge
due to the 2" diameter of the leading edge being a bit larger than the radius
shown in the tables.

At zero degrees AoA the CP is at 40%.
At 12 degrees AoA it has moved forward to 30%

In my work, I've ASSUMED that the front spar would only receive 70% of the
total load. That makes a tremendous difference in the amount of deflection
of the spar, and, seems to be much closer to what we observe in the actual
structure in flight.

I think this also explains why Beeson could build a wing using .035 wall spars
tubes. My crude work on those indicates they wouldn't survive 2 G's at 100%
load. But they do - although with noticeable deflection under load in flight.

Just to be through, the wing structure should also be mounted at, in this
case, 12 degrees nose down (it's inverted, remember) to account for the
angle of attack at the test load. This will have the effect of pulling the
load vector forward some, but the magnitude is tiny compared to a 30% offset.


The other improvements I noted should/could be made HAVE NEVER BEEN
IMPLEMENTED to the best of my knowledge.

Hey, I'm not saying it's a bad idea.
Like you pointed out there are some real benefits to it.

Rivet heads under the fabric are a pain to work around.
On my first parasol (PBJ) I use a thin piece of wood molding on the
outboard side of the top longeron to avoid that.

On the second one I just used flush rivet - and avoided the problem
without adding the extra weight.


As for the extruded aluminum truss construction, using the sizes
listed in the plans, and the rivets specified, it is difficult, if not
impossible, to achieve proper hole edge clearances in MANY locations.
I know, for an ultralight there are no inspections, so you can get
away with it - but you are NOT building to acceptable aircraft
standards if proper edge clearances can not be maintained.


The edge margins for thin sheet are well known and easily found.
I'm not having much luck locating the tables for Lugs on short notice.

The difference, as I recall, is the relative thickness of the metal being
bolted or riveted. Those extrusions are five times thicker that .025 sheet
metal.

But I'm still looking for it and will post it here when I find it.

Examining the results of some of the accidents, even the one straight in
on the nose fatality, you do not find broken rivets. The angles bent, but
seldom even break. In the bad one, the first bay of the fuselage truss was
crumpled up like an accordion.


The Texas Parasol is just an angle aluminum Baby Ace in concept -
shortened and with bigger tailfeathers to compensate.

It's a Texas airplane, guys. Texans just GOTTA have a lot of tail!

Apparently you built yours one station longer, making it the same
dimensions as the Ace. The wings are the same dimensions and planform
as well, from what I understand. So the CONCEPT is a good one.
The plane CAN be built as a safe, economical, fun-to-fly plane - but
NOT as per plans.

It's still quite a bit smaller than a Baby Ace.

The added 15 inches was for weight and balance purposed only.
A full dressed 2180 VW can weigh well over 200 pounds.
Compared to a light weight 2 stroke, that can create a - situation!

It was nearly TOO much extra tail arm as it was tough getting the CG
far enough _forward_ to stay in an acceptable range. I think we've
got it worked out though. Just had to come up with a lighter tail wheel
and leg.

But tell everyone how you built yours. It was not strictly to plans.
What about the leave in the spar??

I don't know where that rumor came from.
The wing on the new plane was built mainly according to the plans,
with the exception of boxing in the compression struts at the strut
attach bay. My reason for that was that the struts on this plane angle
in a bit at the fuselage end, creating a small compression load at the spar
ends. Probably not really necessary, but it made me feel better.

The internal sleeves are as per plans.

I also added a short .017 sheet metal cover over the leading edge.
I'd not think that's a structural thing - purely cosmetic.

A FULL truce is as close as the corrections to the plans. Just because
nobody's killed themselves YET does not mean the plans, as they exist
today, are safe. By your admission, many builders ARE making changes.

Well, I think that was more of an accusation than an admission, Clare.

I have had one friend who was killed in his.
It was a hard loss to deal with.
And it gave me pause to seriously reconsider.

Please believe me folks, if we had ANY experience that indicated there were
real structural problems with the thing, I'd be the first one to address them.

But the physical evidence simply does not support that claim.

At least - as shown in the plans - and not "improved" to be faster, heavier, etc.


Mission Requirements:

It is intended to be a very inexpensive, very light (ALmost UL), very slow,
SINGLE seat baby buggy.

Hand tools only - with very little welding (the main gear axle clusters) and
little if any machine work needed.

Relatively tolerant of "workmanship" issues.

Protection for the pilot in the advent of an accident. (be real, folks!)

Good flying qualities, and fun to fly.


If that's not what you want, this is not the airplane to build.

And I'd appreciate it if people would NOT try to make it into something it was
never intended to be.
There in lies the real danger.


Richard

"Morgans" wrote in message
...

wrote

The dry weight of the prototype was 200 lbs and it was designed
for 400 lbs gross, by real engineers.

I could not fly it, and I'm by no means, a lard butt. Under 170 lbs for
the pilot, it looks like to me.
--
Jim in NC

I admit the same problem, due mostly to height. It would need to be scaled
up, which is not always a good idea, since it is difficult to scale myself
down. I am making some progress on the width and gross weight part of the
problem. :-)

None the less, an interesting design--even though it apears to be so
"traditional" as to use a tail skid to double as a brake.

Peter

Peter Dohm wrote:
"Morgans" wrote in message
...

wrote

The dry weight of the prototype was 200 lbs and it was designed
for 400 lbs gross, by real engineers.

I could not fly it, and I'm by no means, a lard butt. Under 170 lbs for
the pilot, it looks like to me.

To be within design gross with 5 gallons of fuel, yes.

--
Jim in NC

I admit the same problem, due mostly to height. It would need to be scaled
up, which is not always a good idea, since it is difficult to scale myself
down. I am making some progress on the width and gross weight part of the
problem. :-)


The designer was tall ans skinny, over 6' IIRC. Evidently Height is
not the problem that, er, girth is.

None the less, an interesting design--even though it apears to be so
"traditional" as to use a tail skid to double as a brake.


From what I read on the Yahoo club it flies fine with pilots up to 200
lbs
(not sure how much fuel, probably less than 5 gallons). A heavier
pilot erodes the factor of safety. The stress analysis on the airframe
was done by finite element analysis by competent engineers so
you can be confident in the factor of safety, you know how much you
have left if you fly over gross.

--

FF

Not the crumbling yellowed pages I remembered, but give this a try...

Try he http://trs.nis.nasa.gov/archive/0000...1/asm-B200.pdf

On Sun, 19 Feb 2006 00:25:35 GMT, Richard Lamb
wrote:

clare at snyder.on.ca wrote:

Clare, thanks for taking a reasonable position and tone.
Muchly appreciated.
I'll reply as best I can, ok?

Richerd,
You are getting ahead of yourself.
Forget the pictures you saw in the Rec Av magazine. Those were
projects some guys built. They were NOT the tests done by Gary. Gary
did the tests on a wing BUILT ACCORDING TO PLANS, and IT FAILED THE
TEST.

That was not my take from the article, but if I'm wrong on that point,
I'll offer an apology.

The Test:

I've never been offered any description of the set up - only the conclusions.

The wing was supported as it would be on the plane, but inverted. It
was then loaded with sandbags to iminent failure, with the load
properly distributed. It was tested both with and without the jury
strut. The jury strut is VERY CRITICAL (and it's attatchment according
to the plans was not sufficient) and even with the jury strut upgraded
the wing did not meet the specified G rating for the design specified
gross weight. IIRC it is a 500 lb wing, not a 600 - but my memory of
that detail may be fuzzy. What I DO know, is it did NOT meet the
published spec, or the required G load for the published maximum gross
weight.

As I understand it, it was assumed that the front spar would take 100% of the
load. That is, of course, true IF the spar is located at the center of
pressure - as a normal wing is arranged.

There were mo assumptions made. The wing was properly supported and
loaded.

But the wing in question is obviously NOT arranged that way.
The spars are at the leading and trailing edges while the center of pressure
remains back around 30% to 40% of the chord.

The airfoil used is a Clark-Y. There is a minor deviation at the leading edge
due to the 2" diameter of the leading edge being a bit larger than the radius
shown in the tables.

Which also causes aproblem when a larger spar diameter is used. IIRC
it makes the stall more abrupt -which you do NOT want.

At zero degrees AoA the CP is at 40%.
At 12 degrees AoA it has moved forward to 30%

In my work, I've ASSUMED that the front spar would only receive 70% of the
total load. That makes a tremendous difference in the amount of deflection
of the spar, and, seems to be much closer to what we observe in the actual
structure in flight.

I think this also explains why Beeson could build a wing using .035 wall spars
tubes. My crude work on those indicates they wouldn't survive 2 G's at 100%
load. But they do - although with noticeable deflection under load in flight.

And Chuck BUILT the .035 wing, but did not fly it, from what I
understand, as the wing was too flimsy even for HIS level of comfort.

Just to be through, the wing structure should also be mounted at, in this
case, 12 degrees nose down (it's inverted, remember) to account for the
angle of attack at the test load. This will have the effect of pulling the
load vector forward some, but the magnitude is tiny compared to a 30% offset.


The other improvements I noted should/could be made HAVE NEVER BEEN
IMPLEMENTED to the best of my knowledge.

Hey, I'm not saying it's a bad idea.
Like you pointed out there are some real benefits to it.

Rivet heads under the fabric are a pain to work around.
On my first parasol (PBJ) I use a thin piece of wood molding on the
outboard side of the top longeron to avoid that.

On the second one I just used flush rivet - and avoided the problem
without adding the extra weight.


As for the extruded aluminum truss construction, using the sizes
listed in the plans, and the rivets specified, it is difficult, if not
impossible, to achieve proper hole edge clearances in MANY locations.
I know, for an ultralight there are no inspections, so you can get
away with it - but you are NOT building to acceptable aircraft
standards if proper edge clearances can not be maintained.


The edge margins for thin sheet are well known and easily found.
I'm not having much luck locating the tables for Lugs on short notice.

The difference, as I recall, is the relative thickness of the metal being
bolted or riveted. Those extrusions are five times thicker that .025 sheet
metal.

But I'm still looking for it and will post it here when I find it.

1.5 times the hole diameter rings a bell.


Examining the results of some of the accidents, even the one straight in
on the nose fatality, you do not find broken rivets. The angles bent, but
seldom even break. In the bad one, the first bay of the fuselage truss was
crumpled up like an accordion.


The Texas Parasol is just an angle aluminum Baby Ace in concept -
shortened and with bigger tailfeathers to compensate.

It's a Texas airplane, guys. Texans just GOTTA have a lot of tail!

Apparently you built yours one station longer, making it the same
dimensions as the Ace. The wings are the same dimensions and planform
as well, from what I understand. So the CONCEPT is a good one.
The plane CAN be built as a safe, economical, fun-to-fly plane - but
NOT as per plans.

It's still quite a bit smaller than a Baby Ace.

The added 15 inches was for weight and balance purposed only.
A full dressed 2180 VW can weigh well over 200 pounds.
Compared to a light weight 2 stroke, that can create a - situation!

It was nearly TOO much extra tail arm as it was tough getting the CG
far enough _forward_ to stay in an acceptable range. I think we've
got it worked out though. Just had to come up with a lighter tail wheel
and leg.

But tell everyone how you built yours. It was not strictly to plans.
What about the leave in the spar??

I don't know where that rumor came from.
The wing on the new plane was built mainly according to the plans,
with the exception of boxing in the compression struts at the strut
attach bay. My reason for that was that the struts on this plane angle
in a bit at the fuselage end, creating a small compression load at the spar
ends. Probably not really necessary, but it made me feel better.

The internal sleeves are as per plans.

I also added a short .017 sheet metal cover over the leading edge.
I'd not think that's a structural thing - purely cosmetic.

A FULL truce is as close as the corrections to the plans. Just because
nobody's killed themselves YET does not mean the plans, as they exist
today, are safe. By your admission, many builders ARE making changes.

Well, I think that was more of an accusation than an admission, Clare.

I have had one friend who was killed in his.
It was a hard loss to deal with.
And it gave me pause to seriously reconsider.

Please believe me folks, if we had ANY experience that indicated there were
real structural problems with the thing, I'd be the first one to address them.

But the physical evidence simply does not support that claim.

At least - as shown in the plans - and not "improved" to be faster, heavier, etc.


Mission Requirements:

It is intended to be a very inexpensive, very light (ALmost UL), very slow,
SINGLE seat baby buggy.

Hand tools only - with very little welding (the main gear axle clusters) and
little if any machine work needed.

Relatively tolerant of "workmanship" issues.

Protection for the pilot in the advent of an accident. (be real, folks!)

Good flying qualities, and fun to fly.


If that's not what you want, this is not the airplane to build.

And I'd appreciate it if people would NOT try to make it into something it was
never intended to be.
There in lies the real danger.


Richard

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On Sun, 19 Feb 2006 02:57:31 GMT, Richard Lamb
wrote:

Not the crumbling yellowed pages I remembered, but give this a try...

Try he http://trs.nis.nasa.gov/archive/0000...1/asm-B200.pdf
I wasn't tlking lugs. I was talking fastening uprights etc to
longerons, and the firewall area as well. Any place 2 aluminum parts
are joined by drilling and riveting or bolting.Specifically the
extruded members of the truss. Up here we are encouraged (required) to
maintain the same edge margins as on sheet.
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Clare,

You seem to be pretty well connected up there.
And you concerns are (believe it or not) well taken.

May I ask if it might be possible to collect whatever information
IS available from that test? Initial assumptions, load distribution,
deflections noted (preferably at any given load, if possible), etc.

Last night there was a message on the Texas Parasol list that indicated
that the spar tube in question had actually kinked.

The only thing I'd heard before is that the rig was in danger of
imminent collapse - but no details as to what was meant by that.


I've never been offered even a scrap of this kind of information - only
the final conclusion. And that rather loudly...

If you really believe there is an issue here, what would it hurt?


Thanks,

Richard

All right, back to the beheadings!


Four days, and not a mumblin' word.
Makes a body wonder, don't it?

Seriously, if the intent is to protect the innocent and unwary, why NOT
respond (and show your work?).

Or? Have I misinterpreted obviously altruistic motives?
(huh!)


I've been trying to raise the RAA web site for several days to see if they
post their articles on the web. But it seems to be snowed under and won't be
back up until the spring thaw.

Fortunately (or otherwise, depending on your point of view?), I just happen
to HAVE a copy of the magazine. It was sent to me by a Canadian fellow (who
I'll not name to avoid allegations of international espionage).

But here it is, and we'll let the reader decide for him/her/it self...

http://www.home.earthlink.net/~tp-1/
page-1.jpg to page-6.jpg

I particularly like the ripe irony of the last paragraph of the article.



There are also a few of the stress analysis reports in pdf format.

ul-spar.pdf The original preliminary report (corrected! The original
original showed an 8 G limit(!), but it was a simple error)

ul-redo.pdf Suggested upgrade to 4.4 Gs at 650 lbs

fastner.pdf rivets, bolts, etc

For what it's worth, none of these are my own works.
They were posted to the Fly5k list by the author and are presented here
for enlightenment and entertainment of (any?) interested readers...

Richard