Today's Message Index:
----------------------
1. 05:04 AM - Re: Re: Long fuselage and Model A (JERRY)
2. 07:17 AM - Re: Long fuselage and Model A (tkreiner)
3. 12:04 PM - Re: Pietenpol-List Digest: 3 Msgs - 01/18/17 (jarheadpilot82)
4. 01:10 PM - Re: Re: Pietenpol-List Digest: 3 Msgs - 01/18/17 (Steven Dortch)
5. 01:22 PM - straight axle stiffener project (Douwe Blumberg)
6. 07:13 PM - Brazil Air Camper looking for wht n bal info + Piets flying (oakesje)
7. 08:33 PM - Re: straight axle stiffener project (taildrags)
8. 08:58 PM - Re: Long fuselage and Model A (taildrags)
Message 1
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| Subject: | Re: Long fuselage and Model A |
Thanks again Oscar. I have attached a picture of my fuse measurements. Most
of the length is in the front of the fuse.
Thanks
Jerry
-----Original Message-----
From: owner-pietenpol-list-server@matronics.com
[mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of taildrags
Sent: Monday, January 23, 2017 10:02 PM
Subject: Pietenpol-List: Re: Long fuselage and Model A
--> <taildrags@hotmail.com>
Jerry; I would be happy to help you with whatever information you want to
know about the long fuselage. I own a complete set of Pietenpol Family
plans from which no Air Camper has yet been constructed, and I also have a
set from which my airplane was built. I think everyone in this group is in
favor of a builder/pilot knowing exactly what he/she has, and sharing
information from the plans can help you build and fly safely.
A few quick dimensional checks of your fuselage sides will tell which of the
various versions of fuselage you've got, and in fact there are some very
detailed fuselage comparisons available in the Matronics list archives. As
I recall, the most complete comparison identifies four different "stock" or
"plans" fuselage variants, although there are probably dozens of one-off
variants.
--------
Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=465385#465385
-----
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Message 2
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| Subject: | Re: Long fuselage and Model A |
Jerry,
You might contact Bob Dewenter in OH, who has a spreadsheet that will calculate
weight & balance.
Since we don't have a photo of your project, it's difficult to identify what all
you'll need to input into the spreadsheet. That said, the items will include
all of the existing weights, and dimensions along with the weight of the Model
A/B, engine mount, and associated cooling equipment.
The spreadsheet may be used in an interesting manner, where you can actually use
it to calculate the CG by entering the position of the engine & cooling items,
and modifying those locations. From this info, you can construct the engine
mounting system to place the CG within limits.
Bob has a full set of instructions as to how to use the spreadsheet, and it will
take some working with it to understand what to do, and how to do it, but it
will eliminate all of the hand calculations to answer the questions you have
- at least regarding W&B.
Bob's email is rdewenter (at) woh.rr.com (Forgive me if this results in a flood
of emails, Bob!)
Best of luck in your build - and please post pics!
--------
Tom Kreiner
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=465397#465397
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| Subject: | Re: Pietenpol-List Digest: 3 Msgs - 01/18/17 |
Steve,
An air line pilot's second form of birth control is his layover attire. [Laughing]
--------
Semper Fi,
Terry Hand
Athens, GA
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=465407#465407
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| Subject: | Re: Pietenpol-List Digest: 3 Msgs - 01/18/17 |
LOL
On Jan 24, 2017 2:08 PM, "jarheadpilot82" <jarheadpilot82@hotmail.com>
wrote:
> jarheadpilot82@hotmail.com>
>
> Steve,
>
> An air line pilot's second form of birth control is his layover attire.
> [Laughing]
>
> --------
> Semper Fi,
>
> Terry Hand
> Athens, GA
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=465407#465407
>
>
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| Subject: | straight axle stiffener project |
Hey all,
Just finished a fun winter project.
The axle for the "Jenny " gear calls for 1/8th wall, 1 1/2" od tubing. it is
plenty strong for the Ford Piet as designed, but some of our heavier ladies
have experienced varying degrees of bending. After four seasons of flying,
Re-Piet's big wheels began to show a noticeable "camber" meaning the axle
was taking on a permanent bend/bow. I know some people who have went to a
thicker wall, which adds a ton of weight and some have paid a fortune to
have the axle heat-treated by a specialty company. After much thinking and
discussing with engineer friends, I made a new axle to the standard
measurements and layed up a carbon fiber bar (mold shown). I made it about
1/4" thick, then trimmed it for a slip fit into the axle. This was then
sandwiched between two pieces of hard foam and shaped the whole enchilada
for a nice slip fit. I then coated the inside of the axle and the enchilada
with epoxy and slid it into the axle so the carbon bar will be vertically
oriented. it goes all the way to each end of the axle so there's no new
"stress point" introduced. it only weighed a few ounces and it should
certainly help. basically we're creating a I beam out of the tube by
introducing the central web.
we'll see how this one holds up to the extra weight and my occasional
"carrier landing"...
Douwe
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| Subject: | Brazil Air Camper looking for wht n bal info + Piets flying |
Fabrizio emailed me asking about wht n bal questions for his Air Camper - his contact
info is Fabrizio Bolelli fabrizio.bolelli@electrolux.com; bolellif@yahoo.com.br;
I'm just a learner so uncomfortable providing any advice, thought i'd
post it here plus i've told him about this forum in case he has access.
I'm flying the Pietenpol Adrian Meilleur had, the newly overhauled A75 Continental
is pretty awesome, amazing to have every cylinder with compression now!! Time
to get ready for another flight to Pietenpol Meca :) who else is planning
to fly in?
Jill
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=465412#465412
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| Subject: | Re: straight axle stiffener project |
Douwe: this is very interesting. Now for my disclaimer: I'm no structural engineer!
However, in my humble opinion, the effectiveness of this hybrid composite
structure (your internally-braced Jenny axle) in resisting bending is going
to be maximized by a good epoxy bond between the carbon 'bar' and the steel tube
walls. The hard foam filler will certainly stabilize things to resist buckling
or warping of the bar under bending loads, no problem there. Now whether
the full potential of the bar is developed will be determined by its ability
to accept tension loads in its lower strands as the bending is transferred to
the bar from the steel tube. If you got a good epoxy bond between them and you
ensure that the bar is vertical with respect to axle travel in the gear legs,
it sounds like you've got yourself a very elegant solution to stiffening the
axle without adding significant weight!
There are builders who take the "bigger hammer" approach like me, and then there
are artists like yourself ;o)
--------
Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=465416#465416
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| Subject: | Re: Long fuselage and Model A |
Jerry; it looks like what you've got there is a one-off variant. For your information,
here's a snip from a very thorough dissertation on Piet fuselage length
variations by Chris Bobka, from around 2004. He's responding to a question
from builder Walt Evans and it has to do with the axle location because that's
pretty important to how the airplane will handle on the ground, but look past
some of that to see the information on some key dimensions. Get a piece of
scratch paper and a pencil and sketch it out. You might check some other dimensions
on your airframe, but you may very likely have a hermaphrodite there...
but not unprecedented. And by the way, Walt Evans built and flew his absolutely
gorgeous Air Camper successfully, and you can see pictures of it on the Westcoastpiet.com
site. Here's one such picture:
http://www.westcoastpiet.com/images/WB%20Evans/images/1200Fly.jpg
Note that Chris refers to a "Pavliga long fuselage" (Frank Pavliga, a legend in
the Piet world)- with a fuselage of 172.375" long. If I've added up the numbers
in your sketch correctly, your fuselage is 172" long, so there is at least
one other airplane out there flying with a fuselage that is within 3/8" of being
the same length as yours and Pavliga's. Not to worry though... the laws
of physics still apply, which means that one or more of the very useful CG calculation
spreadsheets out there will help you build and fly a safe airplane.
We put men on the moon with nothing more than slide rules... so anything is possible
if you have a spreadsheet. Here's some reading for you, snipped from the
archives.
================
The 1932 fuselage (Hoopman drawings and 1932 Flying and Glider Manual) is 161 inches
long. The 1933 Improved Air Camper fuselage is 163 inches long. The Pavliga
long fuselage is 172.375 inches long. This is the one I understand you
have built.
It appears that the intersection of the first truss verticals with the lower longeron
on the 1932 fuselage is 8.375 or 8.5 inches aft of the firewall, depending
on which set of plans you look at. On the 1933 Improved fuselage, it is 10
inches, and on the Pavliga long fuselage, it is 12 inches. This would mean
that the wood gear, unmodified from the 1932 plans and as mounted on the Pavliga
long fuselage, would put the axle 12-8.5 or 3.5 inches farther aft on the long
fuselage than on the 1932 fuselage. It would be at 13.5 (see paragraph 1
sentence 1) + 3.5 or 17 inches aft of the firewall. Is this a good place for
it? Frank P. said it was too far forward at 17 inches aft of the firewall so
he moved it aft when he did the engine switch.
A better indicator of proper gear position is comparing it to the rear seat back
position in the particular fuselage since this indicates the shift aft of the
CG position as the fuselages have been stretched. The rear seat back (at the
top longeron) in the 1932 fuselage is 70.5 inches aft of the firewall. The
rear seat back in the 1933 Improved fuselage is 72.25 inches aft of the firewall.
The rear seat back of the Pavliga long fuselage is 76.25 inches aft of the
firewall. This is a substantial shift aft in the position of the CG versus
the axle position as the fuselage is stretched.
Therefore, the axle on the 1932 fuselage is 70.5 -13.5 or 57 inches forward of
the rear seat back. The axle on the 1933 Improved is 72.25 -17 or 55.25 inches
forward of the rear seat back. Let us ignore the value from the 1932 fuselage
for reasons to be discussed later. Using the number from 1933 and applying
this to the Pavliga long fuselage, we should have the axle at 76.25 - 55.25 or
21 inches aft of the firewall. Two paragraphs ago we determined that it will
actually wind up at 17 inches aft of the firewall with the wood gear, unmodified,
and Frank P. says this is too far forward. Therefore, it appears that we
need to redesign the gear so that the axle will sit farther aft in the V to the
tune of about 21 -17 or 4 inches.
As we noted above, if you look at the sweep of the V in the 1932 plans, you will
note that the front attach of the V is at 8.5 inches aft of the firewall. We
know that the axle is about 13.5 inches aft of the firewall. Therefore, the
sweep is 13.5 - 8.5 or 5 inches for the wood gear. Doing the same analysis for
the 1933 Improved Air Camper, we know the front attach of the V is at 10 inches
aft of the firewall and the axle is at 17 inches aft of the firewall. Therefore
the sweep is 17 -10 or 7 inches for the split axle gear. The next sentence
is important. If you put the 1932 wood gear on a 1933 Improved fuselage, you
would have an axle that will be 7 - 5 or 2 inches forward of where it would
have been if you had used the split axle gear!!!! So the gears are not necessarily
interchangeable!!! Logic says that it does not matter which style gear
you use. The axle should always be in the same relative position. I see this
as an admission by BP that the original 1932 axle was too far forward by 2 inches.
And now we know what Frank P. was talking about!!!!
It is obvious that BP saw fit, when designing the 1933 Improved Air Camper, that
if he lengthened the fuselage from 161 to 163 inches and moved the pilot's rear
seat back aft by 1.75 inches, then he must move the axle aft by 17 -13.5 -
2 or 1.5 inches. (Consider 2 of the 3.5 inch difference between 17 and 13.5
as a design correction and the remaining 1.5 of the 3.5 inches to be an adjustment
for the new fuselage length and movement aft of the rear seat back.) So
what would BP do if he made the fuselage 172.375 inches long (a whopping 9.375
inches longer) and moved the rear seat back aft yet another 76.25 -72.25 or 4
inches?
--------
Oscar Zuniga
Medford, OR
Air Camper NX41CC "Scout"
A75 power, 72x36 Culver prop
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=465417#465417
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