Today's Message Index:
----------------------
1. 04:26 AM - Re: FW: Fuse construction (RAMPEYBOY@aol.com)
2. 05:26 AM - Re: FW: Fuse construction (Skip-Cinda Gadd)
3. 07:14 AM - proper prop for A-75 piet (Andimaxd@aol.com)
4. 07:24 AM - Re: FW: Fuse construction (Rcaprd@aol.com)
5. 07:30 AM - Re: FW: Fuse construction (RAMPEYBOY@aol.com)
6. 07:34 AM - Re: FW: Fuse construction (Rcaprd@aol.com)
7. 09:14 AM - Re: proper prop for A-75 piet (Dick Navratil)
8. 10:45 AM - Re: FW: Fuse construction (Rick Holland)
9. 11:14 AM - Re: Fuse construction (Gene Rambo)
10. 11:38 AM - Re: Fuse construction ()
11. 11:20 PM - Re: Fuse construction (Dick Navratil)
12. 11:24 PM - Re: proper prop for A-75 piet (Rcaprd@aol.com)
13. 11:46 PM - Re: Fuse construction / Bartlesville Flight (Rcaprd@aol.com)
Message 1
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| Subject: | Re: Fuse construction |
In a message dated 9/22/2006 11:34:13 P.M. Eastern Daylight Time,
Rcaprd@aol.com writes:
That energy has to be absorbed somewhere, and that cross piece is the place
Chuck I'm no engineer, but what you said there got me thinking. Maybe this
energy should be absorbed by bowing this metal cross piece? If you stiffen this
piece, then does some more critical (or more difficult to replace/repair)
part then have to take the load? Food for thought...
Boyce
Message 2
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| Subject: | Re: Fuse construction |
Chuck,
I have seen this strap bent down on several Piets at Brodhead.
What I believe happens is, you have end grain of a hard wood, ash cross piece,
pushing into side grain of soft wood spruce, lower longerons. Grega noticed this
and changed from a strap, tension only to a U-channel, tension and compression.
It is one on the Grega mods I am adopting for my Piet. I am using 4130 rectangular
tube, because it is lighter than any U-channel I could find.
Hope you have great weather for Bartlesville, the Wx here is scud and storms.
Skip, Hales Landing WV
----- A hard landing applies a lot of negative G's to the lift strut, as well
as when the landing gear bottoms out, pushes that cross piece into a bow away
from the belly. That energy has to be absorbed somewhere, and that cross piece
is the place. I've seen this on several other Pietenpols, too. The problem
seems to be isolated to the front one. I now have three #10 bolts down through
the ash cross piece and this steel cross brace, and just this evening, I
see where it has bent down a little bit between two of these bolts. I must have
logged well over 500 landings in my plane, and I obviously still bounce one
in once in a while !!
Chuck G.
NX770CG
Smokin' to Bartlesville in the morning !!
Message 3
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| Subject: | proper prop for A-75 piet |
Hey guys,
I have become a lurker, but, I need some feedback from you guys on props. I
have a prop off of a 65hp Aeronica mounted to my A-75 piet. I'm developing
2300-2400 rpm's. I was curious what others are using with their piets with
A-75's and what kind of number they're getting. I was visiting with Jim
Markle and he dug this up for me:
An A-75 is merely an A-65 that is rated at a higher rpm. The pistons are
different and the rods are drilled for extra cooling of piston skirt at the
higher rpm. The carb has a slightly larger venturi and different jetting. The
motor is timed slightly different. The prop is the only thing that actually
makes a difference in performance; the other changes are only for longevity at
higher rpm. A65 is rated at 2300,2150 cruise. A75 is rated at 2650,2300 cruise.
The extra rpm is the only thing increasing horsepower: if your prop is not
allowing the motor to wind up to proper rpm you simply have an A65. If you have
an A65 that turns 23-2400 in a climb you have the performance of an A75.
There was a C-75 which was a slow running version of C-85, but A65 to A75
conversions are much more common. A75 prop generally would be slightly less
diameter and 2-3 inches less pitch than A65, but generally rpm is the only big
change. With proper prop A75 will climb slightly better and cruise about same
as
A65, but at higher rpm.With an A65 prop an A75 will climb exactly the
same(because it is the same!) but you could cruise at 2300 which would be several
mph
faster. Regardless, in the real world the weight of the airplane will make
more difference than A65 vs. A75. In my opinion a metal prop is far superior
to wood in thrust. Wood has less inertia and better throttle response, but
metal definitely performs better. I like an A65 to turn about 2300 in 75 mph
climb. That means about 25-2600 straight and level. Cruise about 2250 and you
are still less than 75% at cruise.
P. S. There was no C65 only A65's .A series was A40,A50, A65,A75,and A80. C
series had slightly more displacement(188 cu .in. vs 173 cu. in.). C series
was C75,C85 at 188 cu.in.and C90 at 200 cu .in.
All that being said, I would like some exact performance numbers, prop
numbers and manufactures, so I'll know what to start looking for. Currently I
have a Univar 72 X 42, and according to the above I've got a 65hp engine on my
aero plane. NX101XW is a little on the heavy side and so is the pilot, so I
would like all of the potential climb that I can get (Without going to an
O-200 or something!). I think I would like to stick with a wooden prop, unless
there is just a huge amount of additional thrust/climb from metal. Well, let
me know what you guys think, hell, maybe I should just stick with what I've
got. It (engine) would be de-rated and should last longer?
Any comments/help is greatly appreciated and as usual, thanks in advance,
later.
Max Davis
Arlington, TX.
NX101XW (Reserved)
Message 4
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| Subject: | Re: Fuse construction |
In a message dated 9/23/2006 6:29:54 AM Central Standard Time,
RAMPEYBOY@aol.com writes:
That energy has to be absorbed somewhere, and that cross piece is the place
Chuck I'm no engineer, but what you said there got me thinking. Maybe this
energy should be absorbed by bowing this metal cross piece? If you stiffen this
piece, then does some more critical (or more difficult to replace/repair) part
then have to take the load? Food for thought...
Boyce
Yes, you certainly are right about the energy being absorbed by another
part. However, bowing the cross piece is NOT the answer, because then you will
be wallowing out the bolt holes at the lug fittings. I think this cross
piece is just the weakest link, and the robust design of the Pietenpol can
certainly handle the load, wherever it is transferred.
The whole trick is...to land as softly as a Butterfly with sore feet !!
:)
Chuck G.
NX770CG
Message 5
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| Subject: | Re: Fuse construction |
In a message dated 9/23/2006 10:26:18 A.M. Eastern Daylight Time,
Rcaprd@aol.com writes:
The whole trick is...to land as softly as a Butterfly with sore feet !! :)
We do that all the time don't we?? I mean when nobody is watching!
Message 6
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| Subject: | Re: Fuse construction |
In a message dated 9/23/2006 7:29:15 AM Central Standard Time,
csfog@earthlink.net writes:
Chuck,
I have seen this strap bent down on several Piets at Brodhead.
What I believe happens is, you have end grain of a hard wood, ash cross
piece, pushing into side grain of soft wood spruce, lower longerons. Grega noticed
this and changed from a strap, tension only to a U-channel, tension and
compression. It is one on the Grega mods I am adopting for my Piet. I am using
4130
rectangular tube, because it is lighter than any U-channel I could find.
Hope you have great weather for Bartlesville, the Wx here is scud and storms.
Skip, Hales Landing WV
I agree with ya, Skip. I think you have a good mod there, just so the
rectangle tube isn't very wide on the minor axis, and the wall thickness doesn't
have to be as thick as the strap, either.
I sure do miss those West Virginia hills !! Hey...WVU is kickin' butt in
football !!
GO MOUNTAINEERS !!!
Chuck G.
NX770CG
Message 7
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| Subject: | Re: proper prop for A-75 piet |
You said a whole lot more than I ever knew on this subject, thanks a lot
for the info. ai have an A-65 with a Sensenich 72x42 prop.
The only problem I have with your numbers is towards the end you talk
about the performance of the A-65. I checked my manual, the A-65 is
only rated to 2300 rpm. If I do 2300 rpm at 75 mph there is little if
any climb. My best climb speed is around 55-60 mph and then I am turning
about 2050 rpm, full throttle. I have never seen more than 2300 rpm.
Dick N.
----- Original Message -----
From: Andimaxd@aol.com
To: pietenpol-list@matronics.com
Sent: Saturday, September 23, 2006 9:13 AM
Subject: Pietenpol-List: proper prop for A-75 piet
Hey guys,
I have become a lurker, but, I need some feedback from you guys on
props. I have a prop off of a 65hp Aeronica mounted to my A-75 piet.
I'm developing 2300-2400 rpm's. I was curious what others are using
with their piets with A-75's and what kind of number they're getting. I
was visiting with Jim Markle and he dug this up for me:
An A-75 is merely an A-65 that is rated at a higher rpm. The pistons
are different and the rods are drilled for extra cooling of piston skirt
at the higher rpm. The carb has a slightly larger venturi and different
jetting. The motor is timed slightly different. The prop is the only
thing that actually makes a difference in performance; the other changes
are only for longevity at higher rpm. A65 is rated at 2300,2150 cruise.
A75 is rated at 2650,2300 cruise. The extra rpm is the only thing
increasing horsepower: if your prop is not allowing the motor to wind up
to proper rpm you simply have an A65. If you have an A65 that turns
23-2400 in a climb you have the performance of an A75. There was a C-75
which was a slow running version of C-85, but A65 to A75 conversions are
much more common. A75 prop generally would be slightly less diameter and
2-3 inches less pitch than A65, but generally rpm is the only big
change. With proper prop A75 will climb slightly better and cruise about
same as A65, but at higher rpm.With an A65 prop an A75 will climb
exactly the same(because it is the same!) but you could cruise at 2300
which would be several mph faster. Regardless, in the real world the
weight of the airplane will make more difference than A65 vs. A75. In my
opinion a metal prop is far superior to wood in thrust. Wood has less
inertia and better throttle response, but metal definitely performs
better. I like an A65 to turn about 2300 in 75 mph climb. That means
about 25-2600 straight and level. Cruise about 2250 and you are still
less than 75% at cruise.
P. S. There was no C65 only A65's .A series was A40,A50, A65,A75,and
A80. C series had slightly more displacement(188 cu .in. vs 173 cu.
in.). C series was C75,C85 at 188 cu.in.and C90 at 200 cu .in.
All that being said, I would like some exact performance numbers, prop
numbers and manufactures, so I'll know what to start looking for.
Currently I have a Univar 72 X 42, and according to the above I've got a
65hp engine on my aero plane. NX101XW is a little on the heavy side and
so is the pilot, so I would like all of the potential climb that I can
get (Without going to an O-200 or something!). I think I would like to
stick with a wooden prop, unless there is just a huge amount of
additional thrust/climb from metal. Well, let me know what you guys
think, hell, maybe I should just stick with what I've got. It (engine)
would be de-rated and should last longer?
Any comments/help is greatly appreciated and as usual, thanks in
advance, later.
Max Davis
Arlington, TX.
NX101XW (Reserved)
Message 8
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| Subject: | Re: Fuse construction |
Skip
I have also built a hybrid main gear using the Piet and GN-1 plans. The
fuselage gear fittings are straight Pietenpol and the gear tubing and cabane
are based on the GN-1 plans, and I added spring struts. So I also have the
2" wide strap between the gear fittings. I noticed yesterday that with the
fuse sitting on the gear without an engine and me (about 450 lbs. of dead
weight) the front strap is already bowed a little away from the fuselage.
What if a piece of rectangular tubing (as long as would fit between the
fittings) was welded along the two inch strap? Probably only on the front
strap since the back doesn't seem to have the problem. Were you thinking of
something like this Skip or are you also building the GN-1 gear fittings?
Rick H.
On 9/23/06, Skip-Cinda Gadd <csfog@earthlink.net> wrote:
>
> Chuck,
> I have seen this strap bent down on several Piets at Brodhead.
> What I believe happens is, you have end grain of a hard wood, ash cross
> piece, pushing into side grain of soft wood spruce, lower longerons. Grega
> noticed this and changed from a strap, tension only to a U-channel, tension
> and compression. It is one on the Grega mods I am adopting for my Piet. I am
> using 4130 rectangular tube, because it is lighter than any U-channel I
> could find.
>
> Hope you have great weather for Bartlesville, the Wx here is scud and
> storms.
>
> Skip, Hales Landing WV
>
>
> ----- A hard landing applies a lot of negative G's to the lift strut,
> as well as when the landing gear bottoms out, pushes that cross piece into a
> bow away from the belly. That energy has to be absorbed somewhere, and that
> cross piece is the place. I've seen this on several other Pietenpols, too.
> The problem seems to be isolated to the front one. I now have three #10
> bolts down through the ash cross piece and this steel cross brace, and just
> this evening, I see where it has bent down a little bit between two of these
> bolts. I must have logged well over 500 landings in my plane, and I
> obviously still bounce one in once in a while !!
>
> Chuck G.
> NX770CG
> Smokin' to Bartlesville in the morning !!
>
> **
>
> *
>
>
> *
>
>
--
Rick Holland
"Logic is a wreath of pretty flowers, that smell bad"
Message 9
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| Subject: | Re: Fuse construction |
Dan:
Two of THE most talked about bugaboos with the fuselage that have not
been mentioned yet are:
(1) decide on your gear type and location BEFORE building. Retrofitting
the Jenny style gear to the '32 fuselage or later is a bear;
(2) make SURE you understand the construction of the tailpost. Read it,
draw it, read it again. Too many people have glued in two 1/2 inch
pieces and tried to pull them together. It does not work like that.
Even after several readings, it is more difficult in practice than it
looks.
As for the discussion that has made it into this thread regarding the
steel strap across the belly, I maintain that it is not SUPPOSED to take
any compression loads and does not need to be square stock or anything
else. There is nothing wrong with a wooden fuselage or any other
component flexing on landing. The strap was added as an afterthought,
and only as an optional suggestion per the plans, as a safety device to
tie the struts together in case the bolts pulled out of the fuselage. at
the gear/strut fitting. The wood, metal, workmanship, and maintenance
and upkeep of amateur builders in the 1930's was such that a rotten
longeron or two was not out of the question. The quality materials and
workmanship we have on this list, I believe, negates any need for that
strap. I am not going to install it, just something else to bow,
corrode, hold moisture against the wood, and look bad.
Just my two cents worth.
Gene
----- Original Message -----
From: Dan Loegering<mailto:danl@odayequipment.com>
To: pietenpol-list@matronics.com<mailto:pietenpol-list@matronics.com>
Sent: Friday, September 22, 2006 9:08 AM
Subject: Pietenpol-List: Fuse construction
--> Pietenpol-List message posted by: "Dan Loegering"
<danl@odayequipment.com<mailto:danl@odayequipment.com>>
Since it has been rather quiet out here lately, I thought I'd post a
building question to see what kind of tips everyone has.
We should have wood for the fuselages arriving within a week or two
and will start construction on fuse sides shortly after that. The
question is... Were there any points during building the fuselage that
you were stumped at, or that were not entirely clear - and if so, what
did you do to resolve the problem you encountered.
A short history - There are currently two Piet's being constructed
locally, with a third to start as soon as the wood shows up. The first
two are progressing nicely with all wing ribs complete, and all tail
surfaces complete. Both will be powered by A65-8 engines. The third
will begin rib construction and he hasn't decided on engine choice yet.
Of the two currently under construction, we are planning on the long
fuselage version - one at stock 24" width, and one either 26" or 28".
Both will have the "Cub" style gear.
So, relive your building days! What did you enjoy, what did you find
challenging, what did you hate...
Of course the reward will come when we are finished, and some day all
three of us fly to Brodhead in loose formation!
Dan Loegering
Fargo, ND
http://www.matronics.com/Navigator?Pietenpol-List<http://www.matronics.co
m/Navigator?Pietenpol-List>
http://www.matronics.com/contribution<http://www.matronics.com/contributi
on>
Message 10
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| Subject: | Fuse construction |
Amen to that partner.I'm calling mine a Piet no matter what.When it
comes down to some conversation about the plane ,just standin around
shootin the bull ,then I might add in"oh ya it has some Grega mods in
there too" and I'll bet there won't be anyone that will say"well you
can't call that a Piet now",When you go to the museum and you see a
Wright flyer there representing the first flight ,you don't say"that's
not a Wright flyer" because the very first one doesn't exist anymore.It
was wrecked in a crash and they never fixed it or rebuilt the same
model.From then on it evolved.Evolusion is good for Piets sake!
________________________________
From: owner-pietenpol-list-server@matronics.com
[mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Gordon
Bowen
Sent: September 22, 2006 4:16 PM
Subject: Re: Pietenpol-List: Fuse construction
I don't think anyone actually builds the exact plane that Pietenpol
designed, too many modern materials available and necessary. Afterall
who'd want to use a tractor mag when there are better options, or grade
3 bolts. Same goes for the original Rutan designs for the Varieze and
Longeze, every builder adds or subtracts their own mods. That's why
it's called experimental. But we still have the purist out there that
insist it ain't a Piete unless it is build just like Bernard did, fer
git abouut it dreamers. N-1003B's 4130 fuselage, 0-235Lycosauros engine
and Aeronca wings, flies just fine thanks. Got $5 bucks that says my
"Piete" can beat anyone out there's Piete in time to climb to 3000' agl,
even the purist, how about Lakeland in Apr07. Better materials make
better planes, just like the Papa John's Pizza commercial. Think
Bernard would appreciate the improvements and still be proud to stick
his name on the design.
Gordon Bowen
----- Original Message -----
From: harvey.rule@bell.ca
To: pietenpol-list@matronics.com
Sent: Friday, September 22, 2006 11:04 AM
Subject: RE: Pietenpol-List: Fuse construction
When does the plane actually begin to become a gn-1 ?Is it after
the first mod or the last one?A Rose by any other name is still a
Rose.So it is with the Pietenpol.Mine has gn-1 mods but the plans still
say Pietenpol.People who see it say "oh you have a Pietenpol".I don't
correct them and say it is a gn-1,that would be rude.I think,you know
your absolutely right ,it is a Pietenpol,you get a gummy bear!
________________________________
From: owner-pietenpol-list-server@matronics.com
[mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Bill
Church
Sent: September 22, 2006 2:48 PM
To: pietenpol-list@matronics.com
Subject: FW: Pietenpol-List: Fuse construction
<<20060917_134.JPG>>
I think the key word here is "style". Cub style gear, not actual
Cub gear.
The 1933/34 improved Pietenpol Air Camper plans show a split
axle "Cub style" landing gear. The GN-1 was designed to use actual Piper
Cub landing gear. So it is possible to have an authentic Pietenpol Air
Camper with Cub style gear. You need to go back to the Flying and Glider
plans to get the straight axle "Jenny style" gear. And that is authentic
Pietenpol too, since it's not actual Jenny gear either.
Speaking of landing gear, I was at an open house for the Tiger
Boys, up in Guelph, Ontario (Canada) last weekend (got a short ride in a
deHavilland Tiger Moth, piloted by a Hatz builder - that was cool). A
couple of WW1 replicas flew in from nearby Brampton - a Fokker DR-1 and
an S.E.5a. The S.E.5a had interesting landing gear (see photo attached).
It appears to be varnished wood, similar to the Jenny-style Pietenpol
gear, but if you look closely, you'll notice that it's actually
streamlined steel tubing, painted to look like wood. This same technique
could be applied to the Pietenpol Cub STYLE gear, giving the strength of
steel, and the look of wood.
Bill C.
-----Original Message-----
Subject: Re: Pietenpol-List: Fuse construction
--> Pietenpol-List message posted by: "Roman Bukolt"
--> <conceptmodels@tds.net>
Cub style gear?? Those must be GN-1's not Pietenpol. The
GN-1 is a
modified Pietenpol with enough changes to no longer be called a
Pietenpol.
ronics.com/Navigator?Pietenpol-List
Message 11
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| Subject: | Re: Fuse construction |
Gene and all
Tell me if I am wrong here in thinking that since I am using the Jenny
type LG, these issues dont apply. The cross brace wires and the bungees
absorbing shock straight upwards shouldn't cause compression loading in
the same way. Am I correct about that?
Dick N.
----- Original Message -----
From: Gene Rambo
To: pietenpol-list@matronics.com
Sent: Saturday, September 23, 2006 1:06 PM
Subject: Re: Pietenpol-List: Fuse construction
Dan:
Two of THE most talked about bugaboos with the fuselage that have not
been mentioned yet are:
(1) decide on your gear type and location BEFORE building.
Retrofitting the Jenny style gear to the '32 fuselage or later is a
bear;
(2) make SURE you understand the construction of the tailpost. Read
it, draw it, read it again. Too many people have glued in two 1/2 inch
pieces and tried to pull them together. It does not work like that.
Even after several readings, it is more difficult in practice than it
looks.
As for the discussion that has made it into this thread regarding the
steel strap across the belly, I maintain that it is not SUPPOSED to take
any compression loads and does not need to be square stock or anything
else. There is nothing wrong with a wooden fuselage or any other
component flexing on landing. The strap was added as an afterthought,
and only as an optional suggestion per the plans, as a safety device to
tie the struts together in case the bolts pulled out of the fuselage. at
the gear/strut fitting. The wood, metal, workmanship, and maintenance
and upkeep of amateur builders in the 1930's was such that a rotten
longeron or two was not out of the question. The quality materials and
workmanship we have on this list, I believe, negates any need for that
strap. I am not going to install it, just something else to bow,
corrode, hold moisture against the wood, and look bad.
Just my two cents worth.
Gene
----- Original Message -----
From: Dan Loegering
To: pietenpol-list@matronics.com
Sent: Friday, September 22, 2006 9:08 AM
Subject: Pietenpol-List: Fuse construction
--> Pietenpol-List message posted by: "Dan Loegering"
<danl@odayequipment.com>
Since it has been rather quiet out here lately, I thought I'd post a
building question to see what kind of tips everyone has.
We should have wood for the fuselages arriving within a week or two
and will start construction on fuse sides shortly after that. The
question is... Were there any points during building the fuselage that
you were stumped at, or that were not entirely clear - and if so, what
did you do to resolve the problem you encountered.
A short history - There are currently two Piet's being constructed
locally, with a third to start as soon as the wood shows up. The first
two are progressing nicely with all wing ribs complete, and all tail
surfaces complete. Both will be powered by A65-8 engines. The third
will begin rib construction and he hasn't decided on engine choice yet.
Of the two currently under construction, we are planning on the long
fuselage version - one at stock 24" width, and one either 26" or 28".
Both will have the "Cub" style gear.
So, relive your building days! What did you enjoy, what did you
find challenging, what did you hate...
Of course the reward will come when we are finished, and some day
all three of us fly to Brodhead in loose formation!
Dan Loegering
Fargo, nbsp; Features Subscriptions
title=http://www.matronics.com/Navigator?Pietenpol-List p; available
via title=http://forums.matronics.com/
-========================
nbsp; Email List title=http://wiki.matronics.com/ nbsp;
generous bsp;
title=http://www.matronics.com/contribution
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Message 12
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| Subject: | Re: proper prop for A-75 piet |
In a message dated 9/23/2006 9:21:49 AM Central Standard Time,
Andimaxd@aol.com writes:
Hey guys,
I have become a lurker, but, I need some feedback from you guys on props. I
have a prop off of a 65hp Aeronica mounted to my A-75 piet. I'm developing
2300-2400 rpm's. I was curious what others are using with their piets with
A-75's and what kind of number they're getting. I was visiting with Jim Markle
and he dug this up for me:
An A-75 is merely an A-65 that is rated at a higher rpm. The pistons are
different and the rods are drilled for extra cooling of piston skirt at the higher
rpm. The carb has a slightly larger venturi and different jetting. The motor
is timed slightly different. The prop is the only thing that actually makes a
difference in performance; the other changes are only for longevity at higher
rpm. A65 is rated at 2300,2150 cruise. A75 is rated at 2650,2300 cruise. The
extra rpm is the only thing increasing horsepower: if your prop is not allowing
the motor to wind up to proper rpm you simply have an A65. If you have an A65
that turns 23-2400 in a climb you have the performance of an A75. There was a
C-75 which was a slow running version of C-85, but A65 to A75 conversions are
much more common. A75 prop generally would be slightly less diameter and 2-3
inches less pitch than A65, but generally rpm is the only big change. With
proper prop A75 will climb slightly better and cruise about same as A65, but at
higher rpm.With an A65 prop an A75 will climb exactly the same(because it is
the same!) but you could cruise at 2300 which would be several mph faster.
Regardless, in the real world the weight of the airplane will make more difference
than A65 vs. A75. In my opinion a metal prop is far superior to wood in
thrust. Wood has less inertia and better throttle response, but metal definitely
performs better. I like an A65 to turn about 2300 in 75 mph climb. That means
about 25-2600 straight and level. Cruise about 2250 and you are still less than
75% at cruise.
P. S. There was no C65 only A65's .A series was A40,A50, A65,A75,and A80. C
series had slightly more displacement(188 cu .in. vs 173 cu. in.). C series was
C75,C85 at 188 cu.in.and C90 at 200 cu .in.
All that being said, I would like some exact performance numbers, prop
numbers and manufactures, so I'll know what to start looking for. Currently I
have
a Univar 72 X 42, and according to the above I've got a 65hp engine on my aero
plane. NX101XW is a little on the heavy side and so is the pilot, so I would
like all of the potential climb that I can get (Without going to an O-200 or
something!). I think I would like to stick with a wooden prop, unless there
is just a huge amount of additional thrust/climb from metal. Well, let me know
what you guys think, hell, maybe I should just stick with what I've got. It
(engine) would be de-rated and should last longer?
Any comments/help is greatly appreciated and as usual, thanks in advance,
later.
Max Davis
Arlington, TX.
NX101XW (Reserved)
Hey Max,
That was a great post, explaining the differences of the A65 & A 75
engines. The holes drilled in the rods squirt oil up under the bottom of the
piston / cylinder on the opposite side - for cooling effect, and the A75 pistons
have fins inside, above the wrist pin. The wrist pins are actually smaller on
the A75.
I think you should check your tach with an electronic hand held tach, to
see if your panel mounted one is accurate. If you are actually developing
2300 to 2400 rpm on static run up, then you will probably get to the rated rpm
of
the A75 engine (2600 rpm), once the prop unloads in straight level flight.
The Overhaul Manual notes: Prolonged running of the engine at or near "FULL
THROTTLE" position should be avoided on the ground.
I don't get anywhere near 2300 rpm on my full power static run up, with
my A65 and homebuilt 72 X 42 prop. When I built my prop, to get the shape of
the blades, I used the planform that Orin Hoopman drew up for the Model A
engine. I think I get about 2000 rpm (maybe a little less) on full power static
run up (brakes don't hold it), and when the prop unloads in straight level
flight, full power run yields just under 2300 rpm. I re-worked my prop two
different times in order to eventually get the rpm up to the rated power...not
by
decreasing the diameter or pitch, but by removing material from the trailing edge
of the blades, about half way out the diameter, and blending in the curved
forward surface, thus reducing the chord of the blades.
On a high drag plane like the Pietenpol, I don't think you should
decrease the diameter of the prop in order to get a higher rated rpm. High drag
airplanes require a large diameter prop. I think it would be MUCH better to
decrease the pitch of the prop.
It's true that a metal prop is more efficient, because it is a thinner
blade. However, a metal prop on an antique plane like the Piet, just looks too
much out of place.
All that said, I think you should always check, and re-check after in
service, the balance of the prop, and just stick with what you have, and fly the
plane for 50 or 60 hrs, and then decide if you want to mess around with
changing props.
Chuck G.
NX770CG
Message 13
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| Subject: | Re: Fuse construction / Bartlesville Flight |
In a message dated 9/24/2006 1:22:36 AM Central Standard Time,
horzpool@goldengate.net writes:
Gene and all
Tell me if I am wrong here in thinking that since I am using the Jenny type
LG, these issues dont apply. The cross brace wires and the bungees absorbing
shock straight upwards shouldn't cause compression loading in the same way. Am
I correct about that?
Dick N.
Dick,
Yes, you are right on. I think this is the reason the strap wasn't
originally installed in the design. In fact I think B.H.P. called it a 'Safety
Strap' for the split axle gear.
On my way to and from Bartlesville today, I sure am glad I had that strap
under there !! It was a Very bumpy ride, both ways. It was also 15 mph to
20 mph Direct crosswind take offs, and landings. There was a LOT planes there,
for an excellent turn out. I met Steve Ruse, and Chet Peek there. Steve is
an enthusiastic Pietenpol guy, and has been flying is plane a LOT. I think he
has about 150 hrs in about 1 1/2 yrs. Chet took care of the B17's in England
in '43 and '44. He has written 6 or 7 books about various light vintage
aircraft, and his latest one is titled 'The Pietenpol Story'. Should be out in
less than a month. I already ordered my copy !!
Chuck G.
NX770CG
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