Today's Message Index:
----------------------
1. 05:05 AM - Re: fixed landing gear (Phillips, Jack)
2. 06:08 AM - Re: Pietenpol Aircraft (hans.vander.voort@alfalaval.com)
3. 07:44 AM - Re: fixed landing gear (Dick Navratil)
4. 07:52 AM - Re: fixed landing gear (Phillips, Jack)
5. 11:23 AM - Re: fixed landing gear (Michael D Cuy)
6. 12:07 PM - Rims and Tires (Kenneth Heide)
7. 12:13 PM - Re: Rims and Tires (Phillips, Jack)
8. 12:21 PM - Re: Rims and Tires (hans.vander.voort@alfalaval.com)
9. 03:01 PM - wheels and rims (lshutks@webtv.net (Leon Stefan))
10. 03:18 PM - Rims and Tires (Kenneth Heide)
11. 09:39 PM - Re: fixed landing gear (Dick Navratil)
12. 09:43 PM - Re: fixed landing gear (Dick Navratil)
Message 1
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Subject: | fixed landing gear |
Sorry to hear that, Dick. It does confirm the stress analysis I did
(unfortunately AFTER my own axle broke). The loading of this axle is
somewhat peculiar in that the stress due to bending moments is constant
in the area between the bungees. In other words, just sleeving the area
around the bungees won't improve things, it will just move the failure
point to the place where the sleeve stops.
What I found when doing some research after my accident was that the
gear should be sized to fail at something between 3 and 5 G's. If you
make it too strong and have a very hard landing, the gear will survive
but will pass the stress on to some less robust part of the airframe,
causing even more expensive damage. For a steel axle to be good to 3
G's (assuming a gross weight of 1100 lbs) with no heat treating (in
other words, normalized 4130 steel), a 1-1/2" axle needs to be .218"
thick. To be good for 4.5 G's (3 G's plus a 150% safety factor), an
un-heat treated axle would need to be solid steel, 1-1/2" diameter and
still would fall somewhat short. This is why I chose to heat treat my
new axle to 130,000 psi tensile strength (105,000 psi yield strength),
allowing me to use the considerably lighter wall thickness of .188" and
still be good to almost 5 G's.
I've attached an Excel spreadsheet that calculates the axle stress. The
variables you can play around with in the spreadsheet are the material
yield strength (60,000 psi for normalized 4130), the distance between
the center of your tire and the center of the bungee attach point, which
determines the bending moment, and the axle diameter and wall thickness.
You can also plug in your actual gross weight.
Once again, this shows the Bernard knew what he was doing when he
designed the "Improved" Air Camper with the split axle gear. The
straight axle can be made very strong (the undercarriage is extremely
rugged), but the axle itself is pretty heavy. The split axle gear can
be equally strong with much less weight.
Jack Phillips, PE
Sr. Manager, Disposables Product Development
Clinical Technologies and Services
Cardinal Health
Creedmoor, NC
(919) 528-5212
-----Original Message-----
From: owner-pietenpol-list-server@matronics.com
[mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Dick
Navratil
Subject: Pietenpol-List: fixed landing gear
I did an inspection of my plane tonight and found that my fixed gear
axle is bent. There is about a 1" deflection in the axle,with the stbd
wheel showing the bend.
I had a bit of a discussion at Brodhead, with Jack Phillips on axle
sizing and Jack, you are right, the 1 1/4" x .125 wall is not heavy
enough for the fixed gear. I have a spare axle of the same size and
will install that but will also sleeve the inside with a 1" oak dowel.
I will then order a new 1 1/2" and install in down time this winter.
Also, one of my cross brace cables is showing the stress threads. I
just replaced the cables before Brodhead. I will up size these cables
to 5/32".
I belive the axle bent last Saturday when I made a full stall landing in
a 15-18 kt cross wind. I should have done a wheel landing, I guess. It
wasn't a horrible touchdown but there were some pretty good side loads
in settling in. The Harley wheels held up very well though.
This was one of those days when the wind was varied and gusting thru 50
degrees.
Dick N.
Message 2
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Subject: | Re: Pietenpol Aircraft |
27, 2005) at 08/26/2005 09:07:57 AM
--> Pietenpol-List message posted by: hans.vander.voort@alfalaval.com
Thanks Robert,
No, I do not have any patterns or plans of the cowling yet.
I just build it, I started off with some foam and shaped a nose bowl.
This foam nose bowl became the male plug/mold for the fiberglass/ epoxy
bowl
I did not make a traditional female mold.
This nose bowl I then mounted on the Prop hub and rest is made from
Aluminum .02- 2024
Same for the Eye brows.
I did not know how big to make them to get good cooling.
So expected to have to remake them, either smaller or bigger.
They seem however spot-on Temperature on full power climb is about 420 F
At 75 Mph cruise it is around 375. And that is in Texas heat of 100 F.
They might be to big for winter.
The Picture gives the cowling more credit than its due, close up there are
a few imperfections.
But it is good enough for flight.
I do intend to redo some of the Cowling, I want to make a aluminum nose
bowl an redo some of the top parts.
I might make some pattern drawings this winter.
Hans
"Robert B.
Holton"
<RHolton@Geospect To
rum.com> <hans.vander.voort@alfalaval.com>
cc
08/25/2005 04:46
PM Subject
Pietenpol Aircraft
Hans,
Your Airplane is beatiful to say the least! I am in the beginning stages
of building a GN-1 Aircamper, and I too want to use a William Wynne
Corvair Conversion. One of the only reasons I have considered not using
the Corvair is because all the Pietenpols I have seen before with this
engine did not have cowlings that I thought were very attractive. Then
you posted the picture of your plane. Once again what a piece of art!
I immediatley focused on the way you cowled your aircraft. It appears
that you have put eye brows on the plane. I love that look, but have only
seen them on Pietenpols with Continentals or Lycomings. Did you design you
own cowl and eye brows to fit the Covrvair Motor? If so do you have
patterns left over that you may be willing to sell to other builders. Let
me know I would be interested.
Robert B. Holton
Message 3
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Subject: | Re: fixed landing gear |
Thanks for all of that, Jack. I was planning on going to a 1.5 x .188 axle. Heat
treating sounds like a very good idea. I have done that with small parts
but how do you dp that on something this large? Also , did you up size your cross
brace cables?
Dick
----- Original Message -----
From: Phillips, Jack
To: pietenpol-list@matronics.com
Sent: Friday, August 26, 2005 7:04 AM
Subject: RE: Pietenpol-List: fixed landing gear
Sorry to hear that, Dick. It does confirm the stress analysis I did (unfortunately
AFTER my own axle broke). The loading of this axle is somewhat peculiar
in that the stress due to bending moments is constant in the area between the
bungees. In other words, just sleeving the area around the bungees won't improve
things, it will just move the failure point to the place where the sleeve
stops.
What I found when doing some research after my accident was that the gear should
be sized to fail at something between 3 and 5 G's. If you make it too strong
and have a very hard landing, the gear will survive but will pass the stress
on to some less robust part of the airframe, causing even more expensive damage.
For a steel axle to be good to 3 G's (assuming a gross weight of 1100 lbs)
with no heat treating (in other words, normalized 4130 steel), a 1-1/2" axle
needs to be .218" thick. To be good for 4.5 G's (3 G's plus a 150% safety
factor), an un-heat treated axle would need to be solid steel, 1-1/2" diameter
and still would fall somewhat short. This is why I chose to heat treat my new
axle to 130,000 psi tensile strength (105,000 psi yield strength), allowing
me to use the considerably lighter wall thickness of .188" and still be good to
almost 5 G's.
I've attached an Excel spreadsheet that calculates the axle stress. The variables
you can play around with in the spreadsheet are the material yield strength
(60,000 psi for normalized 4130), the distance between the center of your
tire and the center of the bungee attach point, which determines the bending moment,
and the axle diameter and wall thickness. You can also plug in your actual
gross weight.
Once again, this shows the Bernard knew what he was doing when he designed the
"Improved" Air Camper with the split axle gear. The straight axle can be made
very strong (the undercarriage is extremely rugged), but the axle itself is
pretty heavy. The split axle gear can be equally strong with much less weight.
Jack Phillips, PE
Sr. Manager, Disposables Product Development
Clinical Technologies and Services
Cardinal Health
Creedmoor, NC
(919) 528-5212
-----Original Message-----
From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Dick Navratil
Sent: Thursday, August 25, 2005 10:43 PM
To: pietenpol-list@matronics.com
Subject: Pietenpol-List: fixed landing gear
I did an inspection of my plane tonight and found that my fixed gear axle is
bent. There is about a 1" deflection in the axle,with the stbd wheel showing
the bend.
I had a bit of a discussion at Brodhead, with Jack Phillips on axle sizing and
Jack, you are right, the 1 1/4" x .125 wall is not heavy enough for the fixed
gear. I have a spare axle of the same size and will install that but will
also sleeve the inside with a 1" oak dowel. I will then order a new 1 1/2" and
install in down time this winter. Also, one of my cross brace cables is showing
the stress threads. I just replaced the cables before Brodhead. I will
up size these cables to 5/32".
I belive the axle bent last Saturday when I made a full stall landing in a 15-18
kt cross wind. I should have done a wheel landing, I guess. It wasn't a horrible
touchdown but there were some pretty good side loads in settling in.
The Harley wheels held up very well though.
This was one of those days when the wind was varied and gusting thru 50 degrees.
Dick N.
Message 4
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Subject: | fixed landing gear |
I didn't upsize the cables, but I used the very stiff 1x19 cable which
is stronger than the 7x19. The only place I found that could heat treat
an axle that long without warping is Rex Heat Treatment in Lansdale, PA.
They do a lot of aerospace parts and have a vertical oven so the part
doesn't lay down and warp. It was not cheap - $475 to do my axle, and
it took about 6 weeks.
Jack
-----Original Message-----
From: owner-pietenpol-list-server@matronics.com
[mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Dick
Navratil
Subject: Re: Pietenpol-List: fixed landing gear
Thanks for all of that, Jack. I was planning on going to a 1.5 x .188
axle. Heat treating sounds like a very good idea. I have done that
with small parts but how do you dp that on something this large? Also ,
did you up size your cross brace cables?
Dick N.
Message 5
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Subject: | fixed landing gear |
--> Pietenpol-List message posted by: Michael D Cuy <Michael.D.Cuy@grc.nasa.gov>
Dick-- my axle is about .20" thick and has survived some pretty rough
landings and a groud loop when my tailwheel shoe
failed.
Mike C.
PS-- the straight axle and wire wheels just look so go to me..I couldn't
even consider the split axle version with donut tires.
Message 6
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Members of the list serve:
I am seeking information on locating a supplier of aluminum rims and hubs. Also
can you recommemd rims size and tires width. Along with that what about hub size
and dimensions.
Just seeking imput for the best possible selection.
Sincerely,
Kenneth M. Heide
Fargo, ND
Message 7
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What kind of wheels? Spoked "Motorcycle" type, or more traditional
aircraft type wheels?
Jack
-----Original Message-----
From: owner-pietenpol-list-server@matronics.com
[mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Kenneth
Heide
Subject: Pietenpol-List: Rims and Tires
Members of the list serve:
I am seeking information on locating a supplier of aluminum rims and
hubs. Also can you recommemd rims size and tires width. Along with that
what about hub size and dimensions.
Just seeking imput for the best possible selection.
Sincerely,
Kenneth M. Heide
Fargo, ND
Message 8
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Subject: | Re: Rims and Tires |
27, 2005) at 08/26/2005 03:21:01 PM
--> Pietenpol-List message posted by: hans.vander.voort@alfalaval.com
Ken,
What landing gear?
Split landingear is what I have, and I used Matco W62 wheels & brakes, 6 x
6.00 tires.
Or straight axle gear with spoked motor cycle wheels, aerodrome aeroplanes
make a nice set.
Hans
Kenneth Heide
<km
.com> To
Sent by: pietenpol-list@matronics.com
owner-pietenpol-l cc
ist-server@matron
ics.com Subject
Pietenpol-List: Rims and Tires
08/26/2005 02:07
PM
Please respond to
pietenpol-list@ma
tronics.com
Members of the list serve:
I am seeking information on locating a supplier of aluminum rims and hubs.
Also can you recommemd rimssize and tires width. Along with that what
about hub size and dimensions.
Just seeking imput for the best possible selection.
Sincerely,
Kenneth M. Heide
Fargo, ND
Message 9
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ETAsAhQXE4C0AvTEpp46yD6DX9tL2YmsKQIULhtztyOxcDzu51uYD+2aBBDBjlc=
--> Pietenpol-List message posted by: lshutks@webtv.net (Leon Stefan)
Hi Ken: I am using Hager hubs and brakes. My wheels are al. atv whels 8"
by 6 wide. nice and light, but not really cheap. Leon S. Ks.
Message 10
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Members of the list:
I am interested in aluminum spoked rims and the width of the motorcycle tire. This
also include suppliers of such, along with size of wheels, etc.....Sorry for
the confusion!
Ken Heide
Message 11
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Subject: | Re: fixed landing gear |
OUCH
----- Original Message -----
From: Phillips, Jack
To: pietenpol-list@matronics.com
Sent: Friday, August 26, 2005 9:52 AM
Subject: RE: Pietenpol-List: fixed landing gear
I didn't upsize the cables, but I used the very stiff 1x19 cable which is stronger
than the 7x19. The only place I found that could heat treat an axle that
long without warping is Rex Heat Treatment in Lansdale, PA. They do a lot of
aerospace parts and have a vertical oven so the part doesn't lay down and warp.
It was not cheap - $475 to do my axle, and it took about 6 weeks.
Jack
-----Original Message-----
From: owner-pietenpol-list-server@matronics.com [mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Dick Navratil
Sent: Friday, August 26, 2005 10:44 AM
To: pietenpol-list@matronics.com
Subject: Re: Pietenpol-List: fixed landing gear
Thanks for all of that, Jack. I was planning on going to a 1.5 x .188 axle.
Heat treating sounds like a very good idea. I have done that with small parts
but how do you dp that on something this large? Also , did you up size your
cross brace cables?
Dick N.
Message 12
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Subject: | Re: fixed landing gear |
--> Pietenpol-List message posted by: "Dick Navratil" <horzpool@goldengate.net>
Ditto here on the wheels.
Dont get me wrong here guys on this bent axle. This was not a near disaster
or anything. I just noticed more deflection than previous and one of the
cables had stressed.
Dick
----- Original Message -----
From: "Michael D Cuy" <Michael.D.Cuy@grc.nasa.gov>
Subject: RE: Pietenpol-List: fixed landing gear
> --> Pietenpol-List message posted by: Michael D Cuy
> <Michael.D.Cuy@grc.nasa.gov>
>
> Dick-- my axle is about .20" thick and has survived some pretty rough
> landings and a groud loop when my tailwheel shoe
> failed.
>
> Mike C.
>
> PS-- the straight axle and wire wheels just look so go to me..I couldn't
> even consider the split axle version with donut tires.
>
>
>
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