Pietenpol plans
Tony Edmundson
What are the significant differences in the various Pietenpol
plans that are out there?? Thanks.
Tony Edmundson
Jim
I just received a new set of the Grega GN-1 drawings. They were $25 when
I bought them 15 years ago and they were well worth it. They are still
$25 but are miniaturized and photo copied so cost is same but quality is
down but still worth it. They're very complete (enough to build from)
They also include both wood and steel airframe dimensions. Haven't seen
the genuine drawingss so can't comment on them.
Just an opinion mindya,
Jim
John R. Johnson
The ONLY Pietenpol plans are the plans from Mr. Pietenpol. There are
others selling plans for similiar aircraft, or extracted from the plans
from Mr. Pietenpol. The Grega GN-1 plans are for a very similiar aircraft
that Mr. Grega developed. They are plans for a very similiar airplane.
Virtually every thing is different. The airfoil is different, the spars
are different, the fuselage is different. Other than being a bit on the
heavy side, it is not a bad airplane. The Pietenpol is quite a bit lighter
and does fly better because of the lighter weight.
The plans from Mr. Pietenpol do have a number of alternatives. There is
the long fuselage for the Corvair engine. There are modifications for the
Continental engine. The original plans worked for the Ford engine. The
CG is fairly critical, and can be adjusted over quite a large range by
slanting the cabane struts to physically move the wing fore and aft.
It is hard to beat the original Pietenpol plans from Don Pietenpol.
John
scott
Tony Edmundson wrote:
>
> What are the significant differences in the various Pietenpol
> plans that are out there?? Thanks.
>
> Tony Edmundson
You might want to check out the Buckeye Pietenpol Association at
http://users.aol.com/bpanews/www.html
Well worth a visit!
Scott (RV-4 building!)
--
Gotta Fly or
Gonna Die !
--Ask me about my
Aeronca Super Chief--
amended 8-29-97: Now after feeling the "Need for Speed", building an
RV-4!
No, the Super Chief is NOT for sale :)
Tom Baker
Bernard Pietenpol's 1930's plans show a wooden fuselage with strap metal
fittings, some not very safe; he made some changes in later years; the
1932 Flying and Glider manual shows a steel tube version, not in great
detail. Both are short, snub nosed fuselages to balance the heavy and
unreliable Ford Model A engine, so that the front seat passenger has no
leg room and only little people will fit in the front hole.
Bernie came up with a new steel tube fuselage in the 1960's or 70's when
he switched to Corvair engines, and he lengthened the nose of the aircraft
accordingly for the lighter engine. His son-in-law was selling these plans
in the 1970's. Grega's variation simply imitated the Piper Cub welded
steel tube fuselage and set it up to take the junk/surplus Cub parts (like
the Cub landing gear) that were all over the place and cheap at the time
(they aren't anymore). The Grega Piet is ugly but stronger and more
practical than the original design, and the fueslage is the right length
for modern engines as drawn.
If you use the old fuselage design with a lighter modern engine you must
lengthen it, carefully, which requires you to re-design it. Grega's other
main contribution is a modern wing airfoil; B. Pietenpol had to invent his
own airfoil in the late 1920's, a high-lift wing to lift the heavy Ford
engine he was stuck with using, and he did (using the old Curtiss Jenny's
as a model), but he had to give up speed for lift and got tons of drag in
the bargain. A Piet with the original wing just creeps through the air
(about 55 knots tops), no matter what engine pulls it. The original
Pietenpol airfoil with its under-hooked (concave) bottom is primitive and
inefficient shouldn't be used unless you too are going to try to lift the
Ford engine; even then there are surely better ones nowadays. But just
forget the Model A anyway unless you are a masochist and don't mind living
dangerously. Also, the original Pietenpol wing is poorly braced inside,
with wooden compression members too widely spaced between the main spars
and weakly braced with overlong lengths of cable and turnbuckles. Grega
copied the Cub, with steel tube compression members, more bays, and strong
threaded steel rod bracing.
If you simply want a simple safe parasol design, something relatively easy
to build and easy to fly, go with Grega's plans and use a modern aero
engine. You will end up with a nice little J-3 Cub-like open cockpit
funplane. Whatever version you build, balance it carefully, especially do
a weight-and-balance on the otherwise-finished plane BEFORE putting the
engine on; so as to calculate the length of the engine mount before
building it, so you will get a safe CG. That of course goes for any
homebuilt.
Tom
In article <34DFF306...@cwnet.com>, le...@cwnet.com wrote:
> Tony Edmundson wrote:
> >
> > What are the significant differences in the various Pietenpol
> > plans that are out there?? Thanks.
> >
> > Tony Edmundson
>
Steve Eldredge
Tom Baker wrote:
> Bernard Pietenpol's 1930's plans show a wooden fuselage with strap
> metal
> fittings, some not very safe; he made some changes in later years; the
>
> 1932 Flying and Glider manual shows a steel tube version, not in great
>
> detail. Both are short, snub nosed fuselages to balance the heavy and
> unreliable Ford Model A engine, so that the front seat passenger has
> no
> leg room and only little people will fit in the front hole.
*A bunch of mindless unstudied/uninformed drivel about a wonderful
little airplane deleted*
I built the piet from Bernies plans, short fuse, continental. This
design has been around longer than 98% of homebuild designs. It first
flew in 1928 and has been built by the hundreds since. I have over 100
current participants/builders on my discussion list of the type. The
historical structural integrity of the design speaks for itself. The
model A still powers 50% of new built examples. The GN-,1 although a
fine copy of the piet, is overdesigned and heavy. For those really
interested check out the Pietenpol homepage @
http://users.aol.com:80/bpanews/www.html
John R. Johnson
On 12 Feb 1998, Tom Baker wrote:
Tom, you sound like you know what you are talking about, but you are
mistaken about several things.
> Bernard Pietenpol's 1930's plans show a wooden fuselage with strap metal
> fittings, some not very safe; he made some changes in later years; the
> 1932 Flying and Glider manual shows a steel tube version, not in great
> detail. Both are short, snub nosed fuselages to balance the heavy and
> unreliable Ford Model A engine, so that the front seat passenger has no
> leg room and only little people will fit in the front hole.
>
did add jury struts because the original struts could buckle with negative
G's, and did once back in the thirties. Nowadays you make the fittings
from 4130 and they are just fine. The front hole is surprisingly roomy
even with the Ford engine.
> Bernie came up with a new steel tube fuselage in the 1960's or 70's when
> he switched to Corvair engines, and he lengthened the nose of the aircraft
> accordingly for the lighter engine. His son-in-law was selling these plans
> in the 1970's.
Bernard's SON, Don Pietenpol sells the plans for all of Bernie's airplanes.
They are still available from him, and they build the best airplane.
> Grega's variation simply imitated the Piper Cub welded
> steel tube fuselage and set it up to take the junk/surplus Cub parts (like
> the Cub landing gear) that were all over the place and cheap at the time
> (they aren't anymore). The Grega Piet is ugly but stronger and more
> practical than the original design, and the fueslage is the right length
> for modern engines as drawn.
>
This is partly true. The Grega variation is set up to take junk/surplus
Cub parts which are now quite dear, but at the time were plentiful and
cheap. The Grega variant uses a wooden fuselage very similiar to the
original Piet fuselage, but heavier. The added strength merely adds
weight. The Grega is certainly NOT more practical. The fuselage is the
right length for modern engines as drawn, but so are the plans from
Pietenpol.
Right. There is a "long" fuselage required for the Corvair engine. The
length is BEHIND the CG and is to compensate for the heavier engine. The
standard short fuselage works fine for the modern engines and is what is
used for most of the Continental and Lycoming powered Piets.
> If you use the old fuselage design with a lighter modern engine you must
> lengthen it, carefully, which requires you to re-design it. Grega's other
> main contribution is a modern wing airfoil;
This is just plain wrong. You do not, and are foolish to attempt to
redesign the airplane from the Pietenpol plans. It was a particularly
apt compromise that is still better than any of the copies I have seen.
Grega did NOT use a modern wing airfoil. He just made the spar and ribs
heavier.
The Pietenpol plans have both the long and the short fuselage versions,
as well as the steel tube and the wood versions. Grega's do not.
B. Pietenpol had to invent his
> own airfoil in the late 1920's, a high-lift wing to lift the heavy Ford
> engine he was stuck with using, and he did (using the old Curtiss Jenny's
> as a model), but he had to give up speed for lift and got tons of drag in
> the bargain. A Piet with the original wing just creeps through the air
> (about 55 knots tops), no matter what engine pulls it.
Clearly you have never flown one of the originals. The ones I flew were
considerably faster than that with the Continental engine.
The original
> Pietenpol airfoil with its under-hooked (concave) bottom is primitive and
> inefficient shouldn't be used unless you too are going to try to lift the
> Ford engine; even then there are surely better ones nowadays. But just
> forget the Model A anyway unless you are a masochist and don't mind living
> dangerously. Also, the original Pietenpol wing is poorly braced inside,
> with wooden compression members too widely spaced between the main spars
> and weakly braced with overlong lengths of cable and turnbuckles. Grega
> copied the Cub, with steel tube compression members, more bays, and strong
> threaded steel rod bracing.
>
Clearly you have not seen the Grega plans. The Grega airfoil is NOT a
modern airfoil. It is basically the same airfoil as Bernard used, but it
is modified for heavier ribs and a thicker and heavier spar. the fuselage
construction differs somewhat on the spacing of the crossmembers and is
a few inches longer. Grega does NOT sell plans for a steel tube fuselage,
and his uses a wooden fuselage with heavier plywood on the sides, and more
of it. He "strengthened" the aircraft significantly. Of course, the
original was much stronger than required, and the "strengthening" Grega
did added more weight than anything else. Since there has never been a
problem with the original strength, strengthening seems redundant and
counter productive.
> If you simply want a simple safe parasol design, something relatively easy
> to build and easy to fly, go with Grega's plans and use a modern aero
> engine. You will end up with a nice little J-3 Cub-like open cockpit
> funplane. Whatever version you build, balance it carefully, especially do
> a weight-and-balance on the otherwise-finished plane BEFORE putting the
> engine on; so as to calculate the length of the engine mount before
> building it, so you will get a safe CG. That of course goes for any
> homebuilt.
>
The Grega plans build a heavier airplane that will not provide the
performance of the Pietenpol plans. The Grega is NOT a J-3 Cub-like
airplane, but is a heavier copy of the Pietenpol. There have been many
built from Grega plans and many from Pietenpol plans. I have built both
and flown both. I have never seen a Grega variation that flew as well
as the Pietenpol design. Why mess with a good thing?
John
Dean W. Humphrys II
Can you invert the kawasaki 440A so that the engine is on the bottom and the
reduction is on the top? What do you need to do? What should I look out
for? I have a 72x36 prop and would like a little more clearance.
Thanks,
Dean
Owen Davies
Tom Baker <jay...@nmia.com> wrote in article
<jaybird-1102...@dialup108.nmia.com>...
> Bernard Pietenpol's 1930's plans show a wooden fuselage with strap metal
> fittings, some not very safe; he made some changes in later years; the
> 1932 Flying and Glider manual shows a steel tube version, not in great
> detail. Both are short, snub nosed fuselages to balance the heavy and
> unreliable Ford Model A engine, so that the front seat passenger has no
> leg room and only little people will fit in the front hole.
WADR to Mr. Baker, please note that his views are a definite minority
position.
Most Piet lovers consider the original--that is, any of the variations that
Mr.
Pietenpol himself designed--to be much the more desirable plane. Many of
them are flying safely and reliably with Model A engines. And, in any
case,
it's probably worth a little compromise with reliability for the privilege
of
listening to the only engine that ever sounded better than a good radial.
However, if you absolutely can't live without a flat four, many, many
people have put small Continentals on their Piets without a problem. The
process is well established after all this time.
As for speed, one of our local Piet builders hung a C-85 on his and cruises
at just over 80. He built it mostly from the 1932 plans, though he had
others
to back them up, and his only problem was moving the wing a few inches to
get the CG right. He did round the nose of the airfoil slightly, but
retained
the reflexed bottom.
Owen Davies
Glenn Scherer
On Thu, 12 Feb 1998 19:08:21 -0800, Mark Lightsey <msdl...@ivic.net>
wrote:
>I don't know why anyone would think the Model A engine is anything less
>than a fine aircraft engine. When properly converted, I'd put it up
>against any of the flat fours. Attached is the conversion I'm using on
>my Corben Super Ace.
Nice looking engine, and the Pietenpol has appealed to me from the
beginning. The only thing about the Model A engine that gives me pause
is those bearings. I have read that these engines can be machined for
modern plain bearings to replace the babbits. Is this common in the
Piet community? Is your engine built this way?
_
| | Glenn Scherer
__| ^~~~: Farmersville, TX USA
\ ^ ) sche...@airmail.net
\/\ /
\_(
John R. Johnson
On Fri, 13 Feb 1998, Glenn Scherer wrote:
> On Thu, 12 Feb 1998 19:08:21 -0800, Mark Lightsey <msdl...@ivic.net>
> wrote:
>
> >I don't know why anyone would think the Model A engine is anything less
> >than a fine aircraft engine. When properly converted, I'd put it up
> >against any of the flat fours. Attached is the conversion I'm using on
> >my Corben Super Ace.
>
> Nice looking engine, and the Pietenpol has appealed to me from the
> beginning. The only thing about the Model A engine that gives me pause
> is those bearings. I have read that these engines can be machined for
> modern plain bearings to replace the babbits. Is this common in the
> Piet community? Is your engine built this way?
>
Glenn,
It is true that the Ford bearings are poured in place babbit. This is
actually superior to the modern plain bearings, which are babbit poured
on a bronze backing so that you can insert it cold. The poured in place
bearings are much less likely to spin! If they are properly scraped in
the fit better that the insert type can. The RPM range the Ford engine
runs in the airplane, there is no particular advantage to maching the
case for insert type bearings. It does take man hours to properly
scrape and fit the babbit bearings, but it does NOT require an unattainable
skill.
John