Today's Message Index:
----------------------
1. 04:54 AM - wooden struts (Douwe Blumberg)
2. 07:24 AM - (Douwe Blumberg)
3. 09:37 AM - Good Fuselage?? (Eric Williams)
4. 09:37 AM - intake air filter material (Michael D Cuy)
5. 10:37 AM - Re: Good Fuselage?? (John Dilatush)
6. 10:44 AM - Re: Good Fuselage?? (Hubbard, Eugene)
7. 10:57 AM - Re: Good Fuselage?? (John Ford)
8. 11:01 AM - Re: Good Fuselage?? (DJ Vegh)
9. 11:57 AM - Re: wooden struts (w b evans)
10. 12:11 PM - Re: Good Fuselage?? (BARNSTMR@aol.com)
11. 12:23 PM - Re: intake air filter material (BARNSTMR@aol.com)
12. 12:36 PM - Re: intake air filter material (Michael D Cuy)
13. 01:01 PM - Re: Good Fuselage?? (Hubbard, Eugene)
14. 01:33 PM - Re: (w b evans)
15. 03:02 PM - Re: (Fred Weaver)
16. 04:11 PM - Re: wooden struts (del magsam)
17. 04:29 PM - Re: Good Fuselage?? (hjarrett)
18. 04:39 PM - Re: (hjarrett)
19. 04:46 PM - Re: Good Fuselage?? (Alex Sloan)
20. 06:03 PM - Re: wooden struts (w b evans)
21. 07:39 PM - Helmets - open cockpit equipment (owner-pietenpol-list-server@matronics.com)
22. 07:46 PM - Re: (Jim Ash)
23. 08:18 PM - Re: Good Fuselage?? (Jim Ash)
24. 08:53 PM - Piet accidents (Sanders, Andrew P)
25. 10:17 PM - Re: Good Fuselage?? (Eric Williams)
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--> Pietenpol-List message posted by: "Douwe Blumberg" <douweblumberg@earthlink.net>
I bought my plane as a project. The builder was a skillfull woodworker who made
everything he could from wood...including the lift/cabane and jury struts.
I saw the article in the backissues he followed. He sandwhiched a quarter inch
piece of marine plywood between two pieces of spruce and bolted long strap type
fittings to the end... like a WWI plane. I'm sure they're a bit heavier.
I've seen few shots in the backissues showing guys using these, and I can't figure
out why they wouldn't be safe, but thought I'd ask everybody's opinion since...
everybody's got one!
Second question. If I do decide to go with metal struts, what dimensions are people
using and where is the best place to get the stock?
Douwe
douweblumberg@earthlink.net
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--> Pietenpol-List message posted by: "Douwe Blumberg" <douweblumberg@earthlink.net>
Okay, another mind bender.
What would happen if one used 100LL avgas in a model A built to run on modern car
gas? I know the temps will be higher, but what else?
Message 3
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--> Pietenpol-List message posted by: "Eric Williams" <ewilliams805@msn.com>
Hi everyone. This is my first posting to this list (although Ive been
lurking for a while) and I have a situation that I would really appreciate
any comments or suggestions on.
While at Oshkosh this year, a very good friend of mine, who has too many
airplanes in various stages of repair, offered to give me a Piet project
that he had acquired several years ago from a friend of his (the builder).
I picked up the project this past weekend and it consists of a completed
fuselage structure with the plywood skin on the forward half and the floor,
a complete set of wing ribs, and a complete set of tail surfaces.
The workmanship on the project looks to be acceptable however, one thing
that bothered me was the longerons and the other fuselage members appeared
to be small in cross-section. The builder happened to stop by while we were
loading it all onto my trailer. He said that he had used douglas fir and
since his research proved to him that fir was 25% stronger than spruce, he
had reduced the dimensions of the members by 25% (from 1" to 3/4"). The
problem with this line of thinking, as I see it, is that when you multiply
3/4" by 3/4" you end up with 0.56 square inches as the cross-sectional area
of the wood that was used, as compared to 1.00 square inch in a 1" x 1"
member. That means the longerons in my fuselage actually contain 44% less
material than had they been built using 1x1 stock.
I would sincerely appreciate any thoughts you all might have as to the
usability of this fuselage. I should say that it "feels" strong and I did
sit in it while it was supported at the approximate landing gear points and
there appeared to be no deflection or creaking at all (there were a few
engine noises made however). I also wonder if I might be able to epoxy some
1/4" strips to the various members for added strength? The builder said he
had used West System epoxy to construct it.
Thanks for your input.
Concerned that messages may bounce because your Hotmail account is over
Message 4
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Subject: | intake air filter material |
--> Pietenpol-List message posted by: Michael D Cuy <Michael.D.Cuy@grc.nasa.gov>
do not archive
Guys-- a little off topic, but just throwing this out since so many of you
are so experienced and knowledgeable in so many areas I had to ask.
Say you have an airplane w/ a Zenith carb (like the Ford engines have) and
operate out of a grass strip and normally fly in the 'bug zone' of 0 to
1500 agl, would an automotive paper/rubber gasket type filter be
acceptable if you got caught in say some light to moderate rain showers
? I know now I have a Brackett oiled foam filter on the Continental so
the rain won't break that down. I do want some kind of filter on the
Zenith carb for fear that a piece of grass or big bug will get in there and
plug something up. I hear some aerobatic planes use no filter.
Thanks !
Mike C. in Ohio where it's 64 beauutiful degrees. Not hot and sticky like
lousy Louisiana ! (just kidding Corky)
Message 5
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Subject: | Re: Good Fuselage?? |
--> Pietenpol-List message posted by: "John Dilatush" <dilatush@amigo.net>
----- Original Message -----
From: "Eric Williams" <ewilliams805@msn.com>
Subject: Pietenpol-List: Good Fuselage??
=================================
Eric,
Welcome to the list!
Your reasoning about the area of the longerons is correct. It is true that
Douglas Fir is about 25% stronger, but then the area can only be reduced by
about 20%. Adding a strip to the existing longerons will not really add
that much strength except in tension.
It should be noted that the Pietenpol fuselage is an extremely strong unit
because the Piets have been powered with engines from 40 to 145 hp that I am
aware of. I would think your decision should be based on the engine and the
type of flying you intend to do.(no aerobatics for instance)
Hope this helps,
John
> --> Pietenpol-List message posted by: "Eric Williams"
<ewilliams805@msn.com>
>
> Hi everyone. This is my first posting to this list (although Ive been
> lurking for a while) and I have a situation that I would really appreciate
> any comments or suggestions on.
>
> While at Oshkosh this year, a very good friend of mine, who has too many
> airplanes in various stages of repair, offered to give me a Piet project
> that he had acquired several years ago from a friend of his (the builder).
> I picked up the project this past weekend and it consists of a completed
> fuselage structure with the plywood skin on the forward half and the
floor,
> a complete set of wing ribs, and a complete set of tail surfaces.
>
> The workmanship on the project looks to be acceptable however, one thing
> that bothered me was the longerons and the other fuselage members appeared
> to be small in cross-section. The builder happened to stop by while we
were
> loading it all onto my trailer. He said that he had used douglas fir and
> since his research proved to him that fir was 25% stronger than spruce, he
> had reduced the dimensions of the members by 25% (from 1" to 3/4"). The
> problem with this line of thinking, as I see it, is that when you multiply
> 3/4" by 3/4" you end up with 0.56 square inches as the cross-sectional
area
> of the wood that was used, as compared to 1.00 square inch in a 1" x 1"
> member. That means the longerons in my fuselage actually contain 44% less
> material than had they been built using 1x1 stock.
>
> I would sincerely appreciate any thoughts you all might have as to the
> usability of this fuselage. I should say that it "feels" strong and I did
> sit in it while it was supported at the approximate landing gear points
and
> there appeared to be no deflection or creaking at all (there were a few
> engine noises made however). I also wonder if I might be able to epoxy
some
> 1/4" strips to the various members for added strength? The builder said
he
> had used West System epoxy to construct it.
>
> Thanks for your input.
>
> Concerned that messages may bounce because your Hotmail account is over
>
>
Message 6
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--> Pietenpol-List message posted by: "Hubbard, Eugene" <ehubbard@titan.com>
Eric,
First the disclaimer: I'm not a structural engineer, and I haven't run the
numbers for the Piet fuselage. I do understand a lot of the physics
involved. I built my Piet fuselage 1 inch spruce longerons.
You're calculations are correct, at least for tensile strength. Stiffness
depends on dimension squared, and goes down even faster. There's a MIL-SPEC
on spruce--I don't have the number handy, but someone on the list probably
does. It lists substitution recommendations for other woods, including
Douglas fir.
On the other hand, there seems to be a general consensus that the Piet is
overbuilt. You could check into the construction used for other wood planes
to get a feeling for what is done. The only data point I (think) I remember
is that I've seen an Ospery I amphibian that appeared to be built of 3/4
inch fir.
Doublers seem like an interesting idea. If I were going to do it that way,
I'd think about 8 long strips on the outsides of the corners, over the
gussets, with filler blocks between the gussets. 1/8 inch Douglas fir over
1/8 inch filler would probably bring your strength back to nominal.
Stiffness would (probably) be better than using 1" spruce. I'd worry a bit
about using a spruce doubler over Douglas Fir because of a difference in
stiffness (Young's modulus to be specific).
Let us know how you decide to go.
Gene Hubbard
San Diego
-----Original Message-----
From: Eric Williams [mailto:ewilliams805@msn.com]
Subject: Pietenpol-List: Good Fuselage??
--> Pietenpol-List message posted by: "Eric Williams" <ewilliams805@msn.com>
Hi everyone. This is my first posting to this list (although Ive been
lurking for a while) and I have a situation that I would really appreciate
any comments or suggestions on.
While at Oshkosh this year, a very good friend of mine, who has too many
airplanes in various stages of repair, offered to give me a Piet project
that he had acquired several years ago from a friend of his (the builder).
I picked up the project this past weekend and it consists of a completed
fuselage structure with the plywood skin on the forward half and the floor,
a complete set of wing ribs, and a complete set of tail surfaces.
The workmanship on the project looks to be acceptable however, one thing
that bothered me was the longerons and the other fuselage members appeared
to be small in cross-section. The builder happened to stop by while we were
loading it all onto my trailer. He said that he had used douglas fir and
since his research proved to him that fir was 25% stronger than spruce, he
had reduced the dimensions of the members by 25% (from 1" to 3/4"). The
problem with this line of thinking, as I see it, is that when you multiply
3/4" by 3/4" you end up with 0.56 square inches as the cross-sectional area
of the wood that was used, as compared to 1.00 square inch in a 1" x 1"
member. That means the longerons in my fuselage actually contain 44% less
material than had they been built using 1x1 stock.
I would sincerely appreciate any thoughts you all might have as to the
usability of this fuselage. I should say that it "feels" strong and I did
sit in it while it was supported at the approximate landing gear points and
there appeared to be no deflection or creaking at all (there were a few
engine noises made however). I also wonder if I might be able to epoxy some
1/4" strips to the various members for added strength? The builder said he
had used West System epoxy to construct it.
Thanks for your input.
Concerned that messages may bounce because your Hotmail account is over
Message 7
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Subject: | Re: Good Fuselage?? |
--> Pietenpol-List message posted by: "John Ford" <Jford@indstate.edu>
I have not begun building yet, so take this for what it's worth. You
did the math and it doesn't look good. I would build a new fuselage
using the existing one for 3-D reference if need be. Then I would be
inclined to either destroy the original (because of the liability if
someone should one day decide to build with it) or convert it to some
sort of plaything for the kids/grandkids. An aquaintance has an
airplane of questionable structural integrity (it had been wrecked) and
has an extremely difficult time fighting the temptation to make it
"flyable" again when it should have gone straight to the scrap yard.
His situation is in many ways a lot like yours, and it scares the heck
out of me to think someone I care about (or anybody) might one day try
to fly something which is likely to break apart (as if by design) once
it gets airborne. Maybe with a passenger too. Maybe one of the kids.
You get the picture. I can see the logic behind overbuilding something,
but to use a fuselage which is demonstrably below-spec seems like a bad
idea to me.
John
John Ford
john@indstate.edu
812-237-8542
>>> ewilliams805@msn.com Wednesday, November 12, 2003 12:37:15 PM >>>
--> Pietenpol-List message posted by: "Eric Williams"
<ewilliams805@msn.com>
Hi everyone. This is my first posting to this list (although Ive been
lurking for a while) and I have a situation that I would really
appreciate
any comments or suggestions on.
While at Oshkosh this year, a very good friend of mine, who has too
many
airplanes in various stages of repair, offered to give me a Piet
project
that he had acquired several years ago from a friend of his (the
builder).
I picked up the project this past weekend and it consists of a
completed
fuselage structure with the plywood skin on the forward half and the
floor,
a complete set of wing ribs, and a complete set of tail surfaces.
The workmanship on the project looks to be acceptable however, one
thing
that bothered me was the longerons and the other fuselage members
appeared
to be small in cross-section. The builder happened to stop by while we
were
loading it all onto my trailer. He said that he had used douglas fir
and
since his research proved to him that fir was 25% stronger than spruce,
he
had reduced the dimensions of the members by 25% (from 1" to 3/4").
The
problem with this line of thinking, as I see it, is that when you
multiply
3/4" by 3/4" you end up with 0.56 square inches as the cross-sectional
area
of the wood that was used, as compared to 1.00 square inch in a 1" x 1"
member. That means the longerons in my fuselage actually contain 44%
less
material than had they been built using 1x1 stock.
I would sincerely appreciate any thoughts you all might have as to the
usability of this fuselage. I should say that it "feels" strong and I
did
sit in it while it was supported at the approximate landing gear points
and
there appeared to be no deflection or creaking at all (there were a few
engine noises made however). I also wonder if I might be able to epoxy
some
1/4" strips to the various members for added strength? The builder
said he
had used West System epoxy to construct it.
Thanks for your input.
Concerned that messages may bounce because your Hotmail account is over
Message 8
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Subject: | Re: Good Fuselage?? |
--> Pietenpol-List message posted by: "DJ Vegh" <aircamper@imagedv.com>
for point of reference.... my dad's Fisher Celebrity (open cockpit biplane) is
made from 5/8 sq. spruce longerons. Design/Construction methods are very similar
to a Piet. His plane has a gross wt. of about 1100lb and is stressed to
+4 -2 as I recall.
My initial thoughts are that your Piet will be strong enough, although I'd keep
the power to something like 65-85hp.
DJ
----- Original Message -----
From: Hubbard, Eugene
Subject: RE: Pietenpol-List: Good Fuselage??
--> Pietenpol-List message posted by: "Hubbard, Eugene" <ehubbard@titan.com>
Eric,
First the disclaimer: I'm not a structural engineer, and I haven't run the
numbers for the Piet fuselage. I do understand a lot of the physics
involved. I built my Piet fuselage 1 inch spruce longerons.
You're calculations are correct, at least for tensile strength. Stiffness
depends on dimension squared, and goes down even faster. There's a MIL-SPEC
on spruce--I don't have the number handy, but someone on the list probably
does. It lists substitution recommendations for other woods, including
Douglas fir.
On the other hand, there seems to be a general consensus that the Piet is
overbuilt. You could check into the construction used for other wood planes
to get a feeling for what is done. The only data point I (think) I remember
is that I've seen an Ospery I amphibian that appeared to be built of 3/4
inch fir.
Doublers seem like an interesting idea. If I were going to do it that way,
I'd think about 8 long strips on the outsides of the corners, over the
gussets, with filler blocks between the gussets. 1/8 inch Douglas fir over
1/8 inch filler would probably bring your strength back to nominal.
Stiffness would (probably) be better than using 1" spruce. I'd worry a bit
about using a spruce doubler over Douglas Fir because of a difference in
stiffness (Young's modulus to be specific).
Let us know how you decide to go.
Gene Hubbard
San Diego
-----Original Message-----
From: Eric Williams [mailto:ewilliams805@msn.com]
Subject: Pietenpol-List: Good Fuselage??
--> Pietenpol-List message posted by: "Eric Williams" <ewilliams805@msn.com>
Hi everyone. This is my first posting to this list (although Ive been
lurking for a while) and I have a situation that I would really appreciate
any comments or suggestions on.
While at Oshkosh this year, a very good friend of mine, who has too many
airplanes in various stages of repair, offered to give me a Piet project
that he had acquired several years ago from a friend of his (the builder).
I picked up the project this past weekend and it consists of a completed
fuselage structure with the plywood skin on the forward half and the floor,
a complete set of wing ribs, and a complete set of tail surfaces.
The workmanship on the project looks to be acceptable however, one thing
that bothered me was the longerons and the other fuselage members appeared
to be small in cross-section. The builder happened to stop by while we were
loading it all onto my trailer. He said that he had used douglas fir and
since his research proved to him that fir was 25% stronger than spruce, he
had reduced the dimensions of the members by 25% (from 1" to 3/4"). The
problem with this line of thinking, as I see it, is that when you multiply
3/4" by 3/4" you end up with 0.56 square inches as the cross-sectional area
of the wood that was used, as compared to 1.00 square inch in a 1" x 1"
member. That means the longerons in my fuselage actually contain 44% less
material than had they been built using 1x1 stock.
I would sincerely appreciate any thoughts you all might have as to the
usability of this fuselage. I should say that it "feels" strong and I did
sit in it while it was supported at the approximate landing gear points and
there appeared to be no deflection or creaking at all (there were a few
engine noises made however). I also wonder if I might be able to epoxy some
1/4" strips to the various members for added strength? The builder said he
had used West System epoxy to construct it.
Thanks for your input.
Concerned that messages may bounce because your Hotmail account is over
=
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Subject: | Re: wooden struts |
--> Pietenpol-List message posted by: "w b evans" <wbeevans@verizon.net>
Douwe,
In the rafters of the nearest old airport hanger.
In the past the various AD's make it manditory to change struts on many G.A.
types. And it seems that anyone that took them off never threw them out. A
friend at a nearby airport told me about the ones there. It was
amazing,,,Zillions of them! (Well , maybe 100)
Being a guy who is honest to a fault, I talked to the airport owner, and
paid , I think, $10.00 apiece. Picked four that matched. The rear J3
strut. The man said that if I found any unusable, to come back and get a
good one.
Problem with the strut on the GA aircraft, was moisture would rot the
bottom. So when you cut off the top and bottom, the inside can be
inspected. All of mine still had the oil inside. My AP gave me the OK, and
saved a bundle. I think the new streamlined tubing goes for about $15.00
per foot.
walt evans
NX140DL
>
> Second question. If I do decide to go with metal struts, what dimensions
are people using and where is the best place to get the stock?
>
> Douwe
> douweblumberg@earthlink.net
>
>
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Subject: | Re: Good Fuselage?? |
--> Pietenpol-List message posted by: BARNSTMR@aol.com
Using the logic that the structure is over-built to begin with, I'd keep the fuselage
and add some plywood gussets (or doublers) in selected high stress areas.
If you do some homework you should be able to identify those areas. The landing
gear and cabane attach points, engine mount points, fuel tank anchor points,
and tailpost come to mind. Some eyeball engineering can go a long way to
distributing loads away from the high stress areas into other parts of the airframe.
Terry L. Bowden
ph 254-715-4773
fax 254-853-3805
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Subject: | Re: intake air filter material |
--> Pietenpol-List message posted by: BARNSTMR@aol.com
Mike
I read an SAE report once on engine contaminants. It pointed out that some airplanes
are designed to operate with alternate air OPEN (unfiltered), except during
takeoff and landing when dust and debris are most likely to be a factor.
This allowed optimum power during climb. I have certified air filters on various
airplanes. The #1 criteria is always to ensure that the filter has a high
capacity (will hold a lot of dirt and still allow the air flow you need). Take
a look at the '94 Ford Mustang filter. It is a cone shape with many many
pleats and is known to be a very high capacity filter. Its basic design philosophy
of the cone shape is about the best you can get for a small filter. The
air flow for a Model A or 65 cont. is a lot less than for a ford mustang. So
a smaller filter of the same basic design would be good. I have noticed such
filters on some of the Rotax engines.
What are you gonna put this Zenith carburetor on? Your A65?
Terry L. Bowden
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Subject: | Re: intake air filter material |
--> Pietenpol-List message posted by: Michael D Cuy <Michael.D.Cuy@grc.nasa.gov>
Thanks for the good info, Terry !
do not archive
Mike C.
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--> Pietenpol-List message posted by: "Hubbard, Eugene" <ehubbard@titan.com>
Eric,
First the disclaimer: I'm not a structural engineer, and I haven't run the
numbers for the Piet fuselage. I do understand a lot of the physics
involved. I built my Piet fuselage 1 inch spruce longerons.
You're calculations are correct, at least for tensile strength. Stiffness
depends on dimension squared, and goes down even faster. There's a MIL-SPEC
on spruce--I don't have the number handy, but someone on the list probably
does. It lists substitution recommendations for other woods, including
Douglas fir.
On the other hand, there seems to be a general consensus that the Piet is
overbuilt. You could check into the construction used for other wood planes
to get a feeling for what is done. The only data point I (think) I remember
is that I've seen an Ospery I amphibian that appeared to be built of 3/4
inch fir.
Doublers seem like an interesting idea. If I were going to do it that way,
I'd think about 8 long strips on the outsides of the corners, over the
gussets, with filler blocks between the gussets. 1/8 inch Douglas fir over
1/8 inch filler would probably bring your strength back to nominal.
Stiffness would (probably) be better than using 1" spruce. I'd worry a bit
about using a spruce doubler over Douglas Fir because of a difference in
stiffness (Young's modulus to be specific).
Let us know how you decide to go.
Gene Hubbard
San Diego
-----Original Message-----
From: Eric Williams [mailto:ewilliams805@msn.com]
Subject: Pietenpol-List: Good Fuselage??
--> Pietenpol-List message posted by: "Eric Williams" <ewilliams805@msn.com>
Hi everyone. This is my first posting to this list (although Ive been
lurking for a while) and I have a situation that I would really appreciate
any comments or suggestions on.
While at Oshkosh this year, a very good friend of mine, who has too many
airplanes in various stages of repair, offered to give me a Piet project
that he had acquired several years ago from a friend of his (the builder).
I picked up the project this past weekend and it consists of a completed
fuselage structure with the plywood skin on the forward half and the floor,
a complete set of wing ribs, and a complete set of tail surfaces.
The workmanship on the project looks to be acceptable however, one thing
that bothered me was the longerons and the other fuselage members appeared
to be small in cross-section. The builder happened to stop by while we were
loading it all onto my trailer. He said that he had used douglas fir and
since his research proved to him that fir was 25% stronger than spruce, he
had reduced the dimensions of the members by 25% (from 1" to 3/4"). The
problem with this line of thinking, as I see it, is that when you multiply
3/4" by 3/4" you end up with 0.56 square inches as the cross-sectional area
of the wood that was used, as compared to 1.00 square inch in a 1" x 1"
member. That means the longerons in my fuselage actually contain 44% less
material than had they been built using 1x1 stock.
I would sincerely appreciate any thoughts you all might have as to the
usability of this fuselage. I should say that it "feels" strong and I did
sit in it while it was supported at the approximate landing gear points and
there appeared to be no deflection or creaking at all (there were a few
engine noises made however). I also wonder if I might be able to epoxy some
1/4" strips to the various members for added strength? The builder said he
had used West System epoxy to construct it.
Thanks for your input.
Concerned that messages may bounce because your Hotmail account is over
Message 14
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--> Pietenpol-List message posted by: "w b evans" <wbeevans@verizon.net>
I don't think it would run hotter. There is no more power in high octane
fuel than low octane fuel.
walt evans
NX140DL
----- Original Message -----
From: "Douwe Blumberg" <douweblumberg@earthlink.net>
Subject: Pietenpol-List:
> --> Pietenpol-List message posted by: "Douwe Blumberg"
<douweblumberg@earthlink.net>
>
> Okay, another mind bender.
>
> What would happen if one used 100LL avgas in a model A built to run on
modern car gas? I know the temps will be higher, but what else?
>
>
Message 15
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--> Pietenpol-List message posted by: "Fred Weaver" <mytyweav@earthlink.net>
But there is a lot more lead in 100 LL than there is in auto fuel.... With
low compression like the Model A has, it could lead to plug fouling and/or
sticky valves..
We used to add TCP from Alcor to eliminate these issues but we can't seem to
find it anymore.......
Fred
----- Original Message -----
From: "w b evans" <wbeevans@verizon.net>
Subject: Re: Pietenpol-List:
> --> Pietenpol-List message posted by: "w b evans" <wbeevans@verizon.net>
>
> I don't think it would run hotter. There is no more power in high octane
> fuel than low octane fuel.
> walt evans
> NX140DL
>
> ----- Original Message -----
> From: "Douwe Blumberg" <douweblumberg@earthlink.net>
> To: "pietenpolgroup" <pietenpol-list@matronics.com>
> Subject: Pietenpol-List:
>
>
> > --> Pietenpol-List message posted by: "Douwe Blumberg"
> <douweblumberg@earthlink.net>
> >
> > Okay, another mind bender.
> >
> > What would happen if one used 100LL avgas in a model A built to run on
> modern car gas? I know the temps will be higher, but what else?
> >
> >
>
>
Message 16
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Subject: | Re: wooden struts |
--> Pietenpol-List message posted by: del magsam <farmerdel@rocketmail.com>
so on a j3 there are two big ones and 2 small ones, which ones did you use?
Del
w b evans <wbeevans@verizon.net> wrote:
--> Pietenpol-List message posted by: "w b evans"
Douwe,
In the rafters of the nearest old airport hanger.
In the past the various AD's make it manditory to change struts on many G.A.
types. And it seems that anyone that took them off never threw them out. A
friend at a nearby airport told me about the ones there. It was
amazing,,,Zillions of them! (Well , maybe 100)
Being a guy who is honest to a fault, I talked to the airport owner, and
paid , I think, $10.00 apiece. Picked four that matched. The rear J3
strut. The man said that if I found any unusable, to come back and get a
good one.
Problem with the strut on the GA aircraft, was moisture would rot the
bottom. So when you cut off the top and bottom, the inside can be
inspected. All of mine still had the oil inside. My AP gave me the OK, and
saved a bundle. I think the new streamlined tubing goes for about $15.00
per foot.
walt evans
NX140DL
>
> Second question. If I do decide to go with metal struts, what dimensions
are people using and where is the best place to get the stock?
>
> Douwe
> douweblumberg@earthlink.net
>
>
Del-New Richmond, Wi
"farmerdel@rocketmail.com"
---------------------------------
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Subject: | Re: Good Fuselage?? |
--> Pietenpol-List message posted by: "hjarrett" <hjarrett@hroads.net>
I have heard many good suggestions but how about just doing a proof load
test on it? You have nothing to loose if it breaks (you wouldn't have
wanted to fly it anyway if it fails and it will burn easier in smaller
pieces). If it passes a proof load you know it is safe and the rest of the
group has more than flapping lips to show that the original design was "over
designed" (which I personally do believe). Even with a detailed stress
analysis I wouldn't fly it without a proof load anyway.
Hank Jarrett
----- Original Message -----
From: "Eric Williams" <ewilliams805@msn.com>
Subject: Pietenpol-List: Good Fuselage??
> --> Pietenpol-List message posted by: "Eric Williams"
<ewilliams805@msn.com>
>
> Hi everyone. This is my first posting to this list (although Ive been
> lurking for a while) and I have a situation that I would really appreciate
> any comments or suggestions on.
>
> While at Oshkosh this year, a very good friend of mine, who has too many
> airplanes in various stages of repair, offered to give me a Piet project
> that he had acquired several years ago from a friend of his (the builder).
> I picked up the project this past weekend and it consists of a completed
> fuselage structure with the plywood skin on the forward half and the
floor,
> a complete set of wing ribs, and a complete set of tail surfaces.
>
> The workmanship on the project looks to be acceptable however, one thing
> that bothered me was the longerons and the other fuselage members appeared
> to be small in cross-section. The builder happened to stop by while we
were
> loading it all onto my trailer. He said that he had used douglas fir and
> since his research proved to him that fir was 25% stronger than spruce, he
> had reduced the dimensions of the members by 25% (from 1" to 3/4"). The
> problem with this line of thinking, as I see it, is that when you multiply
> 3/4" by 3/4" you end up with 0.56 square inches as the cross-sectional
area
> of the wood that was used, as compared to 1.00 square inch in a 1" x 1"
> member. That means the longerons in my fuselage actually contain 44% less
> material than had they been built using 1x1 stock.
>
> I would sincerely appreciate any thoughts you all might have as to the
> usability of this fuselage. I should say that it "feels" strong and I did
> sit in it while it was supported at the approximate landing gear points
and
> there appeared to be no deflection or creaking at all (there were a few
> engine noises made however). I also wonder if I might be able to epoxy
some
> 1/4" strips to the various members for added strength? The builder said
he
> had used West System epoxy to construct it.
>
> Thanks for your input.
>
> Concerned that messages may bounce because your Hotmail account is over
>
>
Message 18
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--> Pietenpol-List message posted by: "hjarrett" <hjarrett@hroads.net>
High octane fuel actually has LESS energy than low octane fuel. It also
burns SLOWER. The whole point of increasing the octane level is to stop
detonation and control the burn in the combustion chamber. This allows
higher compression ratios which lets you pack more air and fuel in each
chamber and THAT gives you more power. There are more pounds of less
efficient fuel being burned so you get less HP per pound but get more total
power by burning more fuel. If you try and use low octane fuel in a high
compression engine it will knock itself apart. If you use fuel with high
lead in a low compression engine the lead can't blow out the exhaust and
deposits in the combustion chamber. ALWAYS use the fuel your engine is
designed for or learn to live with the problems (engines destroyed by
detonation or lead fouling).
Hank Jarrett
----- Original Message -----
From: "w b evans" <wbeevans@verizon.net>
Subject: Re: Pietenpol-List:
> --> Pietenpol-List message posted by: "w b evans" <wbeevans@verizon.net>
>
> I don't think it would run hotter. There is no more power in high octane
> fuel than low octane fuel.
> walt evans
> NX140DL
>
> ----- Original Message -----
> From: "Douwe Blumberg" <douweblumberg@earthlink.net>
> To: "pietenpolgroup" <pietenpol-list@matronics.com>
> Subject: Pietenpol-List:
>
>
> > --> Pietenpol-List message posted by: "Douwe Blumberg"
> <douweblumberg@earthlink.net>
> >
> > Okay, another mind bender.
> >
> > What would happen if one used 100LL avgas in a model A built to run on
> modern car gas? I know the temps will be higher, but what else?
> >
> >
>
>
Message 19
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Subject: | Re: Good Fuselage?? |
--> Pietenpol-List message posted by: "Alex Sloan" <alexms1@bellsouth.net>
It seems to me I recall Bill Rewey telling me he made his with 3/4" sq.
longerons. You can give him a call at 608-833-5839 and verify this. He has
been flying for a number of years.
Alex Sloan
----- Original Message -----
From: <BARNSTMR@aol.com>
Subject: Re: Pietenpol-List: Good Fuselage??
> --> Pietenpol-List message posted by: BARNSTMR@aol.com
>
> Using the logic that the structure is over-built to begin with, I'd keep
the fuselage and add some plywood gussets (or doublers) in selected high
stress areas. If you do some homework you should be able to identify those
areas. The landing gear and cabane attach points, engine mount points, fuel
tank anchor points, and tailpost come to mind. Some eyeball engineering can
go a long way to distributing loads away from the high stress areas into
other parts of the airframe.
> Terry L. Bowden
> ph 254-715-4773
> fax 254-853-3805
>
>
Message 20
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Subject: | Re: wooden struts |
--> Pietenpol-List message posted by: "w b evans" <wbeevans@verizon.net>
Like I mentioned in the mail,,The rear J3 strut. The forward one is really
big.
walt evans
NX140DL
----- Original Message -----
From: "del magsam" <farmerdel@rocketmail.com>
Subject: Re: Pietenpol-List: wooden struts
> --> Pietenpol-List message posted by: del magsam
<farmerdel@rocketmail.com>
>
> so on a j3 there are two big ones and 2 small ones, which ones did you
use?
> Del
>
> w b evans <wbeevans@verizon.net> wrote:
> --> Pietenpol-List message posted by: "w b evans"
>
> Douwe,
> In the rafters of the nearest old airport hanger.
> In the past the various AD's make it manditory to change struts on many
G.A.
> types. And it seems that anyone that took them off never threw them out. A
> friend at a nearby airport told me about the ones there. It was
> amazing,,,Zillions of them! (Well , maybe 100)
> Being a guy who is honest to a fault, I talked to the airport owner, and
> paid , I think, $10.00 apiece. Picked four that matched. The rear J3
> strut. The man said that if I found any unusable, to come back and get a
> good one.
> Problem with the strut on the GA aircraft, was moisture would rot the
> bottom. So when you cut off the top and bottom, the inside can be
> inspected. All of mine still had the oil inside. My AP gave me the OK, and
> saved a bundle. I think the new streamlined tubing goes for about $15.00
> per foot.
> walt evans
> NX140DL
> >
> > Second question. If I do decide to go with metal struts, what dimensions
> are people using and where is the best place to get the stock?
> >
> > Douwe
> > douweblumberg@earthlink.net
> >
> >
>
>
> Del-New Richmond, Wi
> "farmerdel@rocketmail.com"
>
> ---------------------------------
>
>
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Subject: | Helmets - open cockpit equipment |
--> Pietenpol-List message posted by:
Hello!, I suggest you try this site http://www.flightsuits.com/open.html it shows "open cockpit equipment",
good luck!
Carlos Manuel Gonzalez
Message 22
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--> Pietenpol-List message posted by: Jim Ash <ashcan@earthlink.net>
High octane fuel has a higher ignition point temperature, which is how it
reduces detonation in high compression engines.
I've heard some voodoo engineering that the absence of the lead in 100LL
will cause exhaust valves to run hotter and burn up older engines
prematurely. I run a quarter cup of marvel per 12 gallons of fuel to soften
the blow.
Jim Ash
At 11/12/2003 07:42 PM -0500, you wrote:
>--> Pietenpol-List message posted by: "hjarrett" <hjarrett@hroads.net>
>
>High octane fuel actually has LESS energy than low octane fuel. It also
>burns SLOWER. The whole point of increasing the octane level is to stop
>detonation and control the burn in the combustion chamber. This allows
>higher compression ratios which lets you pack more air and fuel in each
>chamber and THAT gives you more power. There are more pounds of less
>efficient fuel being burned so you get less HP per pound but get more total
>power by burning more fuel. If you try and use low octane fuel in a high
>compression engine it will knock itself apart. If you use fuel with high
>lead in a low compression engine the lead can't blow out the exhaust and
>deposits in the combustion chamber. ALWAYS use the fuel your engine is
>designed for or learn to live with the problems (engines destroyed by
>detonation or lead fouling).
>Hank Jarrett
>
>
>----- Original Message -----
>From: "w b evans" <wbeevans@verizon.net>
>To: <pietenpol-list@matronics.com>
>Subject: Re: Pietenpol-List:
>
>
> > --> Pietenpol-List message posted by: "w b evans" <wbeevans@verizon.net>
> >
> > I don't think it would run hotter. There is no more power in high octane
> > fuel than low octane fuel.
> > walt evans
> > NX140DL
> >
> > ----- Original Message -----
> > From: "Douwe Blumberg" <douweblumberg@earthlink.net>
> > To: "pietenpolgroup" <pietenpol-list@matronics.com>
> > Subject: Pietenpol-List:
> >
> >
> > > --> Pietenpol-List message posted by: "Douwe Blumberg"
> > <douweblumberg@earthlink.net>
> > >
> > > Okay, another mind bender.
> > >
> > > What would happen if one used 100LL avgas in a model A built to run on
> > modern car gas? I know the temps will be higher, but what else?
> > >
> > >
> >
> >
>
>
Message 23
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Subject: | Re: Good Fuselage?? |
--> Pietenpol-List message posted by: Jim Ash <ashcan@earthlink.net>
This issue comes up when scaling 'live' engineering to different
dimensions. Scaling itself is a collection of compromises. Scaling
dimensions changes any area-based engineering by a squared relationship,
and volume-based calculations change by a cubed relationship. Obviously the
original builder didn't know this, so I would question what else he didn't
know.
Personally, this is not the kind of project where you can beef-up the parts
that don't 'look' up to snuff, for two reasons. The first is that this is a
truss-based system and you'd be surprised which members are under how much
tension or compression, depending on the load applied at the time. Some of
it is admittedly obvious, but some isn't. It's been 25 years since I've
studied (or used) statics, and I wouldn't attempt this type of analysis
without running back to my old text books first.
The second reason is that an airplane is a collection of structural
systems, each with its limits. When you beef-up one of them, you may be
moving the natural weak points to other systems that shouldn't be subjected
to them. In this case the argument goes the other way. We're talking
failure analysis here.
I don't have any idea how much failure analysis, if any, BHP did, but even
if the Piet is over-built by design, you're cutting into safety margins and
playing with the unknown with these structural members being under-sized.
It's really swell to say you're only going to fly straight and level on
still days, but I want my plane to be able to withstand the stresses when
I've got a double-wide passenger in the front seat and the weather gets
rough or I hit clear-air turbulence.
Jim Ash
At 11/12/2003 03:09 PM -0500, you wrote:
>--> Pietenpol-List message posted by: BARNSTMR@aol.com
>
>Using the logic that the structure is over-built to begin with, I'd keep
>the fuselage and add some plywood gussets (or doublers) in selected high
>stress areas. If you do some homework you should be able to identify
>those areas. The landing gear and cabane attach points, engine mount
>points, fuel tank anchor points, and tailpost come to mind. Some eyeball
>engineering can go a long way to distributing loads away from the high
>stress areas into other parts of the airframe.
>Terry L. Bowden
>ph 254-715-4773
>fax 254-853-3805
>
>
Message 24
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--> Pietenpol-List message posted by: "Sanders, Andrew P" <andrew.p.sanders@boeing.com>
Starting with the list posted here a few days ago, I did some additional research
in the NTSB & FAA databases. I've found 39 Pietenpol Aircamper & Scout, or
Grega accidents listed since 1966.
The 39 can be divided into these categories:
Loss of control/impact: 25, 64%
Failure Engine: 7, 18%
Failure Airframe: 5
Fuel: 2
Loss of control/impact: 25, 64%
Stall/Spin: 13, 33%
Maneuvering: 6, 15%
Takeoff: 4, 10%
Landing: 3, 8%
Impact: 8, 20%
Maneuvering: 3, 8%
Landing 4, 10%
Takeoff: 1, 3%
Loss of control: 5, 13%
Takeoff: 2, 5%
Landing: 2, 5%
Other: 1, 3% Pilot & Copilot each
thought the other had the controls.
Failure Engine: 7, 18%
Corvair: 4, 10% Carb ice, Oil thermostat valve
stuck, cylinder failure, (forgot the last one).
Ford: 2, 5%
Model "A": 1, 3% Sheared prop bolts
and lost prop.
Model "B": 1, 3% Mag failure on single
mag engine.
Continental: 1, 3% Stuck carb needle.
Airframe Failure: 4, 10% Elevator control rod failed, elevator
bellcrank support tube failed, improper turnbuckle barrel, bad landing gear
weld.
Fuel: 2, 5%
Exhaustion: 1, 3%
Water: 1, 3%
Not all the reports listed the type of engine. From the 23 that were listed:
Continental: 11, 48%
A/C-65: 6, 26%
-75: 1, 4%
-80: 1, 4%
-85: 1, 4%
Other: 1, 4%
GM: 6, 26%
Corvair: 4, 17%
Other: 2, 9%
Ford: 4, 17%
Model "A": 2, 8%
Model "B": 1, 4%
Other: 1, 4%
Franklin: 1, 4%
Lycoming: 1, 4%
Please not that in some cases I had to do some interpretation and make a judgment
call it there were more than a single causation listed.
The percentages are rounded and may not add up to 100%
Since the engine was not listed in all cases and wasn't necessarily a factor in
the accidents when listed, I'm not sure that the inclusion of their numbers adds
anything to the accident analysis, but is an interesting point of trivia.
Keep the speed up, keep it in fuel, be proficient. That would have eliminated
3/4 of the accidents.
Andrew
Woodinville, Wa.
Piet wannabe
Andrew Sanders
Boeing 7E7
LSSPD Project Manager
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Subject: | Re: Good Fuselage?? |
--> Pietenpol-List message posted by: "Eric Williams" <ewilliams805@msn.com>
I want to say that I really appreciate all the opinions and suggestions you
guys have given on this topic. Honestly there have been some really good,
thoughtful ideas here. I think I'm going to print them all out and make
them a permanent part of my official builders log. After considering what
you all have said, and listening to my own gut feelings, I think I will
probably end up building a new fuselage. I think laminating strips to the
longerons to bring up the dimension would work if it could be done in one
long continuous piece. The problem there is that many of the gussets and
cross braces would be in the way and would have to be removed to allow for
one nice long strip to be added. At that point we're into disassembling
this fuse and I see that getting messy.
Also, this one is the short version and was built following the original
Flying and Glider manual plans which gives it some different dimensions and
curvatures. I would prefer to build the long version and for it to follow
exactly the more up to date plans so I'm not trying to mix two sets of
dimensions together at some point.
Lastly, this is one of those big "lifetime" projects that I really want to
feel good about and have confidence in. I would hate to go through the
whole building process and be afraid to fly it. As soon as I started
describing to my wife how I might be able to salvage it with all these extra
pieces glued in here and there, she reminded me that I've been down this
road before with other projects and I always end up saying "I wish I had
just done it the right way from the beginning".
But still, even with all that said... there's a completed fuselage in my
garage... and man it bugs me not to use it. I guess I'd better get busy and
build the next one so I can quit whining about it.
Again, thanks for the help guys.
Eric
MSN Shopping upgraded for the holidays! Snappier product search...
http://shopping.msn.com
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