Today's Message Index:
----------------------
1. 06:07 AM - flight testing Greg/Dale's plane (Oscar Zuniga)
2. 07:05 AM - Re: flight testing Greg/Dale's plane ()
3. 07:59 AM - Why lower the leading edge of the stabiliser? (Christian Bobka)
4. 08:11 AM - Re: [Flitzer-Builders] Second Pilot report (Christian Bobka)
5. 08:22 AM - Second pilot report comments (Christian Bobka)
6. 08:23 AM - More comments on second pilot report (Christian Bobka)
7. 08:24 AM - More comments from a noted European aircraft designer (Christian Bobka)
8. 09:41 AM - dihedral (Michael D Cuy)
9. 09:44 AM - flight testing Greg/Dale's plane (Oscar Zuniga)
10. 10:49 AM - Final comments to Mark Crawford the Aussie's post at the bottom (Christian Bobka)
11. 11:15 AM - Cork float fuel-proof varnish? (Steve Ruse)
12. 11:18 AM - Re: Cork float fuel-proof varnish? (Phillips, Jack)
13. 11:26 AM - Re: Cork float fuel-proof varnish? (Michael D Cuy)
14. 11:49 AM - offset thrust line (Oscar Zuniga)
15. 12:01 PM - Carb heat on the Piet (Christian Bobka)
16. 12:56 PM - Re: flight testing Greg/Dale's plane (Textor, Jack)
17. 01:20 PM - Re: Tailwheel control schemes (John E. Joyce)
18. 03:55 PM - Urbana (Isablcorky@AOL.COM)
19. 04:34 PM - Re: Urbana (Larry Nelson)
20. 05:36 PM - Grove Wheels/Brakes (Lynn Knoll)
21. 05:39 PM - Re: dihedral (Galen Hutcheson)
22. 06:49 PM - Re: Urbana (Christian Bobka)
23. 09:13 PM - Re: Cork float fuel-proof varnish? (Rcaprd@aol.com)
24. 10:51 PM - Re: Second Pilot report (Rcaprd@aol.com)
25. 11:16 PM - We mean the same thing (Christian Bobka)
Message 1
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Subject: | flight testing Greg/Dale's plane |
--> Pietenpol-List message posted by: "Oscar Zuniga" <taildrags@hotmail.com>
Chris wrote-
>changed the attack angle of the stabiliser by loosening up the front top
>turnbuckles by two turns and tightening the two lower front turnbuckles
>two turns. This had the effect of increasing the attack angle of the
>stabiliser
>making it more agressive in holding the nose up.
Wait. Wouldn't this *lower* the leading edge of the horizontal stabilizer?
That would indeed have the effect of making the nose go up.
Oscar Zuniga
San Antonio, TX
mailto: taildrags@hotmail.com
website at http://www.flysquirrel.net
Message 2
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Subject: | Re: flight testing Greg/Dale's plane |
--> Pietenpol-List message posted by: <gcardinal@mn.rr.com>
The stabilizer is already pushing down so
lowering the LE would, indeed,
change the angle of incidence and increase
the angle of attack.
Greg Cardinal
----- Original Message -----
From: "Oscar Zuniga" <taildrags@hotmail.com>
Subject: Pietenpol-List: flight testing
Greg/Dale's plane
> --> Pietenpol-List message posted by:
> "Oscar Zuniga" <taildrags@hotmail.com>
>
> Chris wrote-
>
>>changed the attack angle of the stabiliser
>>by loosening up the front top
>>turnbuckles by two turns and tightening the
>>two lower front turnbuckles
>>two turns. This had the effect of
>>increasing the attack angle of the
>>stabiliser
>>making it more agressive in holding the
>>nose up.
>
> Wait. Wouldn't this *lower* the leading
> edge of the horizontal stabilizer? That
> would indeed have the effect of making the
> nose go up.
>
> Oscar Zuniga
> San Antonio, TX
> mailto: taildrags@hotmail.com
> website at http://www.flysquirrel.net
>
>
> Forum -
> Navigator to browse
> Subscriptions page,
> Browse, Chat, FAQ,
>
>
>
Message 3
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d="scan'208"; a="1063437891:sNHT26025756"
"Flitzer" <Flitzer-Builders@yahoogroups.com>
Subject: | Why lower the leading edge of the stabiliser? |
--> Pietenpol-List message posted by: "Christian Bobka" <sbobka@charter.net>
Oscar Oscar Oscar,
Stand off of the LEFT wing tip about 30 feet and look at the airplane. It
should have the nose left and the tail right. From this perspective, the
pitching moment of the airfoil would be anticlockwise. In other words, the
center of pressure, defined as the point under the wing's airfoil where all
the air can be assumed to act, is aft of the center of gravity, the point at
which all the mass can be assumed to be positioned. If the center of
gravity is positioned at 19.5" aft of the leading edge and the center of
pressure is located at the 25% or the 1/4 chord point, as it is on most
airfoils, then a rotation is set up where the wing wants to flip nose over
and over. We see this when the wing comes off of our Sleek Streak rubber
powered 25 cent model that we flew as kids. The wing flips over and over on
the way down.
Therefore, the stabiliser acts downward to counter this rotation. Acting
downward means that it acts as an inverted wing. Lowering the leading edge
of the stabiliser works to increase ITS angle of attack, giving it more bite
into the air helping to force the tail down. We, in effect, "washed in" the
stabiliser.
Taking it further, assume a ship that looks like a Piet weighs 1000 lbs
loaded to fly. At our flight speed, the pitching moment of this ship's
airfoil is rather large requiring a 100 pound aerodynamic downforce at the
tail to keep the nose from tucking under. The wing now has to lift not only
the 1000 pound weight of the ship but also needs to "lift" against the 100
pound downforce of the stabiliser. Therefore, the wing is providing 1100
pounds of lift to fly a 1000 pound airplane. Lift is not free and the two
penalties are imposed is in the form of additional parasite drag due to the
wing being sized to carry 1100 pounds instead of 1000 pounds and, more
importantly and more significantly, the induced drag is commensurate with
1200 pounds of lift not 1000 pounds of lift like you might think. Wait,
1200 pounds? That is 20% higher induced drag than one would think! Yes,
1200 pounds because you are producing 1100 pounds worth of induced drag at
the wing and 100 pounds worth of induced drag at the stabiliser. Induce
drag is induced drag, it results whether the lift vector is up or down and
they do not cancel each other out!
The reason Burt Rutan revived the concept of the canard is so that both
airfoils are working the same way and not against each other. Put the tail
in the front and now it can lift to hold the nose up. If the ship wieghs
1000 lbs, now you can have the wing holding up 900 pounds and the canard
holding up the 100 pound pitching moment yielding a total induced drag
commensurate with 1000 pounds of lift, the ships weight, which is 5/6 of the
case of the tail mounted stabiliser, a significant drag reduction. The wing
area can be now be reduced as it only holds up 900 pounds vice 1100 pounds,
saving weight, which reduces the induced drag, increases the range and/or
payload, etc..
Flitzer los!
Chris
Chris
Braumeister und Inspektor der Flitzer und Flitzermotoren
----- Original Message -----
From: "Oscar Zuniga" <taildrags@hotmail.com>
Subject: Pietenpol-List: flight testing Greg/Dale's plane
> --> Pietenpol-List message posted by: "Oscar Zuniga"
<taildrags@hotmail.com>
>
> Chris wrote-
>
> >changed the attack angle of the stabiliser by loosening up the front top
> >turnbuckles by two turns and tightening the two lower front turnbuckles
> >two turns. This had the effect of increasing the attack angle of the
> >stabiliser
> >making it more agressive in holding the nose up.
>
> Wait. Wouldn't this *lower* the leading edge of the horizontal
stabilizer?
> That would indeed have the effect of making the nose go up.
>
> Oscar Zuniga
> San Antonio, TX
> mailto: taildrags@hotmail.com
> website at http://www.flysquirrel.net
>
>
Message 4
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d="scan'208,217"; a="969252404:sNHT140902746"
"Pietenpol" <pietenpol-list@matronics.com>
Subject: | Re: [Flitzer-Builders] Second Pilot report |
Mark,
We will test your concept in due time and after the left turning tendency is removed.
The problem is that we are at some physical limits as far as the airframe
is concerned. I am afraid that if I add more downthrust now, then at 2000
rpm in cruise, the nose will want to take on a nose down attitude due to the
additional downthrust. This would normally be countered by lowering the leading
edge of the horizontal stabiliser which we can't lower much more by twisting
the LE unless we do a bunch of work at the tail. There is no provision for
shimming or unshimming the horizontal stabiliser as there is on the Flitzer.
As the stabiliser sits on the longeron, lowering the stabiliser front attach point
is not an option. We would instead have to raise the rear spar of the stabiliser.
Doing this would require a reposition of the rudder hinge that is on
the tail post or that is on the rudder which would be difficult. Eventually,
these fixes will need to be incorporated. But that is what winter is for!
We are in flying season now!
Flitzer los!
Chris
Braumeister und Inspektor der Flitzer und Flitzermotoren
----- Original Message -----
From: Mark Crawford
To: Flitzer-Builders@yahoogroups.com
Sent: Wednesday, June 01, 2005 9:39 AM
Subject: Re: [Flitzer-Builders] Second Pilot report
I'm no expert on this matter, but in model aircraft (R/C and free flight) if
the aircraft is climbing a lot with the increasing of power (esp, if tailplane
and wing incidence has been addressed) it normally indicates a need for more
engine downthrust.
Just my 2 cents - don't kill yourself on my advice :P
Mark
----- Original Message -----
From: Christian Bobka
To: Flitzer-Builders@yahoogroups.com
Sent: Wednesday, June 01, 2005 10:11 PM
Subject: Re: [Flitzer-Builders] Second Pilot report
Lynn,
I agree. The enlargement of the vertical stabiliser was recommended in the
first pilot report. A bigger rudder to match was not mentioned by me, though,
but would be commensurate. The fixed portion is the part that is undersized
(undersised?), though, so that should be emphasised.
Bernard Pietenpol did not have any dihedral in any of his ships, like Lindbergh's
NYP or the original Monocoupe/Monoprep, all contemporaries. Many of the
builders think the wing looks like it sags to the point of being drooped at
the tips so they insist on having dihedral. If it were up to me, I would build
it with zero dihedral as it looks the period amd it is what the designer wanted.
Greg is adamant on keeping the tips up. Sad.
Thanks for the input. I will send it on to Greg and Dale. Financially, it
would not be much to effect a change in the verticals. It is merely the price
of the wood, fabric, and paint and the time to do the work. All the fitting
could be retained. This might be 100 dollars/50 pounds. No reinspection needed
under the current rules! At the same time, a shim under the rear spar of
the horizontal stabiliser could be accomodated to make the corrections more permanemt.
Again, no reinspection needed under the current rules! Move to the
US!
Cheers,
Chris
Braumeister und Inspektor der Flitzer und Flitzermotoren
----- Original Message -----
From: Lynn Williams
To: Flitzer-Builders@yahoogroups.com
Sent: Wednesday, June 01, 2005 4:10 AM
Subject: Re: [Flitzer-Builders] Second Pilot report
Chris,
Regarding some of the trimming problems, as yaw and roll are connected, and
these to dihedral effect, since you cannot and need not increase dihedral without
further centre-of-drag issues, then the best solution to some of the wayward
characteristics might be an enlarged fin and rudder with zero dihedral.
Although that may not be really practical from a financial point of view, it would
at least mean that the offset-thrust could be minimised, so the cowling need
not be re-made.
Lynn
----- Original Message -----
From: walter mitchell
To: Flitzer-Builders@yahoogroups.com
Sent: Wednesday, June 01, 2005 7:06 AM
Subject: Re: [Flitzer-Builders] Second Pilot report
A caution for those of us who would casually modify a proven design!
-Von Schneer
----- Original Message -----
From: Christian Bobka
To: pietenpol-list@matronics.com ; Paul Shenton ; Pete Gavin ; Flitzer
Sent: Tuesday, May 31, 2005 10:54 PM
Subject: [Flitzer-Builders] Second Pilot report
There is a lot of good news to report on Greg and Dale's Pietenpol.
This past weekend, we took Chuck Gantzer's and other folks' from around the world
advice and changed the attack angle of the stabiliser by loosening up the
front top turnbuckles by two turns and tightening the two lower front turnbuckles
two turns. This had the effect of increasing the attack angle of the stabiliser
making it more agressive in holding the nose up. At 2000 rpm or so, the
pitch is now in trim in level cruising flight with no forward or aft pressure
required to hold a constant altitude/attitude. At cruising speed, if you increase
the power above 2000 rpm, the nose goes up. If you pull the power to an
amount less than 2000 rpm, the nose will drop. It is obvious from this that
the center of thrust is not colocated with the center of drag, the C of T being
below the C of D.
I identify this as a negative side effect of lengthening the cabane struts
and adding dihedral. The induced and parasitic drag of the wing is a large
component of the total drag of the ship. As the wing is moved higher and
higher above the fuselage, it moves the center of drag up. We are trying to move
the C of T and the C of D closer together, not farther apart. Ideally, they
would be colocated. I would recommend that if you plan to raise the wing an
inch or more from stock location, then raise the thrust line by a like amount
to keep the C of D and C of T relationship intact.
I have recommended to Dale and Greg that they remove the dihedral to
help lower the center of drag. If the tips are 2" higher than the root, it has
the undesireable effect of raising the wing an average of yet another inch.
As for power setting in cruise, the airplane seems to be very comfortable
at 2000 rpm.
The way the power setting effects pitch could be worrisome for a first
time flyer as a departure stall could easily occur unless briefed of the phenomenon
ahead of time. You could "fly the ship off the ground" only to experience
a nose up movement due to the low thrust line that could put you right into
a low altitude stall. Dick Navratil warned me of this as it has bitten him
more than once but he also said that once you know what to do, it is easy to
handle, and that is what I have found. I fly the initial climb out right where
the red turns to white on the Johnson airspeen indicator. This is backed up
by the site picture of the top of the J-3 style eyebrows being held right on
the horizon.
At 2000 rpm, right rudder pedal deflection of about 1/2" to 1" is still
required to hold the ball centered. A little left wing heaviness was still
being experienced early in the day. In addition, it also seemed that whenever
a upward vertical gust was encountered, it was always the right wing that raised
up and not the left. Over the course of the day, the right rear strut was
lengthened a total of two turns on top of adjustments made the previous weekend.
After the above adjustments to the stabiliser and the wing strut, if
power is removed to about 13-1500 rpm in order to approximate a zero thrust glide,
and with hands off the stick, the nose will drop and stay dropped as speed
is gained. It does not appear to try to recover or raise the nose without adding
power to get some thrust acting to pitch the nose up. This is at least
to the speed that I have tested it to which is 80 mph as indicated on the Johnson
airspeed indicator. In addition, with power at this 13-1500 rpm setting,
the aircraft would not need any rudder input nor would it need any roll input.
I am pretty sure that the wing heaviness is now fully corrected. It is difficult
to separate rudder and roll inputs as they are so related but I think that
doing the neutral thrust glides helps to iron this out.
We have taken all the shims out of the motor mount on its right side
but it is apparent that we still need more right thrust to get rid of the remaining
right rudder that must be held at cruise. The next change to be made will
be to add 1/8" shims at top left and bottom left. We are almost to the point
where the cowling does not fit anymore! Believe me when they tell you how
much right thrust you need. It will be a lot!
I also tried a few power-on (2000 rpm) and -off (idle) full rudder side
slips while at altitude to see how the ship would recover. Initial recovery
technique was by removing my foot completely from the fully displaced rudder.
She would slowly return to normal attitude and would positively do so. Of
course, this is still tainted in the power-on condition by the need for yet more
right thrust. As Forrest said, she may be loathe to recover briskly unless
postive input is made. Power-on recovery was a lot better than power-off.
She has so much drag on final that pulling the power to idle and pointing agressively
down will give a good rate of descent at a constant airspeed so slips
to landing should not be often necessary.
The final item to mention is that the motor feels like it is trying to
tumble a bunch of rocks in a rock tumbler. The ship sports a homemade propeller
that Dale made. The prop is copied from an old Sensenich 7242 prop and turns
2200 rpm flat out level. I have a spare Sensenich W70DK-42 with only 20
hours on it since new about 4 years ago that we will try out. This will enable
us to determine whether the homemade prop is out of balance and whether it should
be reshaped to get more RPM. Like his nose bowl, the leading edge on Dale's
creation is rather blunt. Rounding the leading edge more may give us the
needed 100 rpm to make rated power. The W70DK42 propeller is normally used on
an A-75 powered Taylorcraft. I have a few other props to try out and once the
best is found, we will have Dale consider another winter prop project.
Total time now is 6:28 up from 3:40 the previous week.
Flitzer los!
Chris
For Flitzer FAQs and much more, visit the Flitzer Sportflug Verein (Flitzer Sport Flying Association) site at http://www.av8rblake.com/flitzer/
For Flitzer FAQs and much more, visit the Flitzer Sportflug Verein (Flitzer Sport Flying Association) site at http://www.av8rblake.com/flitzer/
For Flitzer FAQs and much more, visit the Flitzer Sportflug Verein (Flitzer Sport Flying Association) site at http://www.av8rblake.com/flitzer/
For Flitzer FAQs and much more, visit the Flitzer Sportflug Verein (Flitzer Sport Flying Association) site at http://www.av8rblake.com/flitzer/
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d="scan'208,217"; a="1152996296:sNHT19659096"
Subject: | Second pilot report comments |
Chris,
Regarding some of the trimming problems, as yaw and roll are connected, and these
to dihedral effect, since you cannot and need not increase dihedral without
further centre-of-drag issues, then the best solution to some of the wayward
characteristics might be an enlarged fin and rudder with zero dihedral. Although
that may not be really practical from a financial point of view, it would at
least mean that the offset-thrust could be minimised, so the cowling need not
be re-made.
Lynn
Message 6
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d="scan'208,217"; a="964387044:sNHT61060554"
Subject: | More comments on second pilot report |
Lynn,
I agree. The enlargement of the vertical stabiliser was recommended in the first
pilot report. A bigger rudder to match was not mentioned by me, though, but
would be commensurate. The fixed portion is the part that is undersized (undersised?),
though, so that should be emphasised.
Bernard Pietenpol did not have any dihedral in any of his ships, like Lindbergh's
NYP or the original Monocoupe/Monoprep, all contemporaries. Many of the builders
think the wing looks like it sags to the point of being drooped at the
tips so they insist on having dihedral. If it were up to me, I would build it
with zero dihedral as it looks the period amd it is what the designer wanted.
Greg is adamant on keeping the tips up. Sad.
Thanks for the input. I will send it on to Greg and Dale. Financially, it would
not be much to effect a change in the verticals. It is merely the price of
the wood, fabric, and paint and the time to do the work. All the fitting could
be retained. This might be 100 dollars/50 pounds. No reinspection needed
under the current rules! At the same time, a shim under the rear spar of the
horizontal stabiliser could be accomodated to make the corrections more permanemt.
Again, no reinspection needed under the current rules! Move to the US!
Cheers,
Chris
Message 7
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d="scan'208,217"; a="964388605:sNHT427261200"
Subject: | More comments from a noted European aircraft designer |
In Greg's position, I'd zero-out the dihedral and build a 'false leading edge'
extension onto the fin, keeping the rudder as is, or maybe adding a fixed rudder
tab, to provide a bit moe bite perhaps. The 'false leading edge' would be fitted
temporarily, but of course, very carefully and safely so it doesn't come
adrift, and see what happens to the handling.
Ultimately a new fin could be fabricated as you've suggested, which would still
convey the character of the Pietenpol. I think the 'drooping' effect created
by the zero dihedral wing, while not uncommon among straight winged biplanes,
parasols, an high-wingers, is partly due to the airfoil section which near the
tip, due to the high undercamber and parallel chord with a squarish tip, creates
a 'downswept' effect from some angles.
I don't see anything wrong with this, which is anyway redolent of so many classic
types from that era, the Ryan NYP, Brougham, and American Eagle being excellent
examples.
Cheers,
Lynn
Message 8
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--> Pietenpol-List message posted by: Michael D Cuy <Michael.D.Cuy@grc.nasa.gov>
sure makes it easier to pee in a bottle by steering with your feet while
your hands
are busy. Beats stopping for fuel when you don't have to on an x-country
and wasting 45 minutes:)
Mike C.
Message 9
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Subject: | flight testing Greg/Dale's plane |
--> Pietenpol-List message posted by: "Oscar Zuniga" <taildrags@hotmail.com>
Chris (and others)- thanks for the explanation; perfectly clear! I guess
what threw me off was the notion that the tailplane is acting as an inverted
wing to provide downforce to the tail, thus in fact lowering the leading
edge (relative to terra firma) INCREASES the angle of attack of the
horizontal stabilizer. Got it!
Funny thing is, I guess I'll be facing this same issue once 41CC is back in
the air. Corky had fitted both a fixed elevator trim tab and an adjustable
bungee around the control stick to apply variable back pressure to the stick
while in level cruise, it requiring steady back pressure to keep the nose up
in cruise. I can also shim the engine to adjust the thrustline (it's off
the mount at the moment). To my knowledge though, the HS is presently
rigged straight and level, so I can still add the two turns or so on the
turnbuckles at the HS to 'wash it in' as you've done on Greg/Dale's plane,
as a first step.
Oscar Zuniga
San Antonio, TX
mailto: taildrags@hotmail.com
website at http://www.flysquirrel.net
Message 10
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d="scan'208,217"; a="964293442:sNHT51107084"
Subject: | Final comments to Mark Crawford the Aussie's post at the |
bottom
Mark,
Maybe there is a reason WHY the rudder in the plans is longer than the tail post
plus the horizontal stabiliser thickness plus the vertical stabiliser height.
As Greg pointed out to me the other day, there is room AVAILABLE for a shim
if only the lower rudder hinge could be easily repositioned.
Mark, In many ways I agree with your statement. The ship originally was short
nosed and made for the heavy Model A Ford, then adapted to a Corvair and a small
Continental which messes up the vertical surface area proportions with those
motors' lighter weight and needed extended nose. Then people got bigger so
they can't get in and out so they raised the wing and shifted it aft and added
a flop for access, and then the ship needed the axle moved to make it handle
on the ground, and then the aft shifted wing, gear, payload, and resulting CG
upsets the tail moment arm (tail volume if you will) of the stabilisers so they
are undersized now and effectively getting smaller as time goes on.
Then the plane is yet heavier with the three piece wing which causes it to cruise
it at a higher angle of attack which increases the pitching moment which calls
for a bigger horizontal stabiliser that nobody is willing to give it.
For these reasons, although I appreciate the Peitenpol design for what it was and
is, it has lost its attractiveness for my purposes although it can get the
builder in the air cheaply, and probably the cheapest, if that is where he wants
to be. And I don't blame him for wanting to be there but the choice should
be rethought. Palns are virtually free and so is the advice which is worth what
you pay for it.
It took I few years for me to make the realiasation that too many changes have
made the design get to the point where it should be redesigned from a clean sheet
of paper, sized and proportioned to be of utmost utility in the future. They
are barely true Pietenpols anymore and all the accomodations and bandaids
speak of this and detract from the excellence of the no longer adequate original.
That is why I have become such a proponent of Lynn William's Staaken Flitzer line
as the aircraft fit today's people, use today's available and reliable motors
(does not the Ferdinand Porche flat four date to 1914 or something like that?
So much for today's motors) like the mere 50 year old Corvair, Rotec R2800,
Aerovee, etc,, yet look REALLY good and period, fly well, and can be constructed
using the same EXACT traditional methods as the Pietenpol and just as inexpensively.
We have it all in the Flitzer line including the cult status the Pietenpol
enjoys. We just need to get the word out.
Much fame could be had (and maybe some money, Gary) if a gifted designer took all
the old classics and made them again viable by upsizing them 10-15% or even
20% and adding 75 years of design experience to economise on the structure while
preserving the ORIGINAL construction methods and handling: Buhl Bull Pup,
Long Longster, Georgias Special, Pietenpol Camper and Scout, Heath Baby Bullet
and Parasol, American Eaglet, Church Midwing, Chilton DW1, UT-1, Urbitis' ships,
and the list goes on and on. Just look at original editions of the Flying
and Glider Manual (not the chopped up EAA editions that are missing half of
the original content). The demand is there but nobody with the ability has stepped
up to the plate except Lynn and he is overwhelmed. I wish I had the ability
but lack the schooling and the process is yet still mystifying to me. For
all the books I have, a hands on, start to finish design has never been put
in book form to the extent that I believe necessary for me to be able to copy
the technique and eventually be able to do it on my own. Hiscocks or Pazmany
come closest but use sheet metal as the medium which is personally undesireable
. This book form analysis would have to include flight testing and retrospective
design analysis as a result of the corrections made in the field as a result
of flight testing. I am truly jealous of the engineer's abilities! It
seems that there is a plethora of magazine articles or series of articles that
nibble at the design process yet never stick to it through to the end. It is
apparent that few individuals possess the designer's ability.
Piper figured it out as 10 years after the J-3 Cub, they upsized it to the PA-18
Super Cub, and that was after upsizing it to the J-5 and PA-12 and PA-14.
I could imagine that the 1929 Piet with a Model A motor and one piece wing built
to the Hoopman plans (really! yeah right) and flown by a 150 pound pilot flies
as sweet as can be. But that design is no longer realistic for today's sized
people.
Mike, don't pee on yourself. And don't forget to zip and don;t get Roscoe caught
in the zipper. Guys, don't shake his hand after he climbs out of his ship
and don't drink any Mountain Dew he may offer you. Uric acid eats at the wood
so be careful of structural deterioration... Inspect and rinse often.
I am not advocating building a GN-1.....
Flitzer los!
Chris
Braumeister und Inspektor der Flitzer und Flitzermotoren
----- Original Message -----
From: Mark Crawford
To: Flitzer-Builders@yahoogroups.com
Sent: Wednesday, June 01, 2005 10:25 AM
Subject: Re: [Flitzer-Builders] Second Pilot report
What a bloody stupid design! Adjusting of tailplane incidence is a pretty important
thing -esp. when homebuilt aircraft are concerned (diff materials, workmanship,
quality, accuracy, engines, etc). As I said "I'm no expert" but at least
the Flitzer has a pretty simple method of adjustment.
Good to hear that the original problems have at least been reduced. At least
the Piet is a tried and true design - even without the adjustable tailplane.
We are getting into our winter now, so have fun in the sun you dogs :P
Mark
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Subject: | Cork float fuel-proof varnish? |
--> Pietenpol-List message posted by: Steve Ruse <steve@wotelectronics.com>
I am replacing the cub-style fuel guage rod in my plane, and would like to
re-coat the cork while I have it out. There are a few chips in the existing
varnish, and I want to make sure it doesn't start absorbing fuel and sink
in-flight, as I've been told this can happen.
Thanks,
Steve Ruse
N6383J - KFTW
Message 12
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Subject: | Cork float fuel-proof varnish? |
--> Pietenpol-List message posted by: "Phillips, Jack" <jphillip@alarismed.com>
I coated mine with Stit's Epoxy Varnish, as I've found that stuff to be
as near bulletproof as any coating I've seen
Jack Phillips
--> Pietenpol-List message posted by: Steve Ruse
<steve@wotelectronics.com>
I am replacing the cub-style fuel guage rod in my plane, and would like
to
re-coat the cork while I have it out. There are a few chips in the
existing
varnish, and I want to make sure it doesn't start absorbing fuel and
sink
in-flight, as I've been told this can happen.
Thanks,
Steve Ruse
N6383J - KFTW
Message 13
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Subject: | Re: Cork float fuel-proof varnish? |
--> Pietenpol-List message posted by: Michael D Cuy <Michael.D.Cuy@grc.nasa.gov>
Steve-- upon the advice of my IA and several restoration guys at our
airport, I dipped
my cork in a can of shellac, let it dry and repeated this about 4
times. No chips or
troubles (like not floating) in almost 7 years of using avgas and a rare
dose of autofuel.
I did re-coat the cork about 2 years ago just to make sure she had a good
seal. Shellac
is light too--epoxies can become heavy I think. Let's hear what the
other experts might
have to say though before you take my word:)
Mike C.
Message 14
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Subject: | offset thrust line |
--> Pietenpol-List message posted by: "Oscar Zuniga" <taildrags@hotmail.com>
As a bit of a support to what Chris said about engine thrustline and how it
affects handling and feel, here's a snip from a post from William Wynne on
this subject. It originally related to where to set the Corvair engine in
the Piet, but the comments are general as well.
=================
Reply from WW:
My Pietenpol had the short 1933 fuselage. The cabane struts were vertical.
The empty weight of the plane was 732lbs., measured on electronic scales. It
had a full electrical system, brakes, tailwheel, etc. The distance from the
firewall to the rear bolt hole was 15". If you are building a newer
fuselage, this will be several inches less. I highly recommend the longer
fuselage. When my plane was painted orange, the thrust line was in the stock
location. When it was blue and silver, I built a new mount which moved the
thrust line up to be in line with the top longeron. It flew slightly better
that way, and I think it looked a lot better... build the motor mount to
give you the correct CG with an appropriately weighted pilot in his seat. We
set this perfectly when I built the second motor mount. With a 150lb. pilot,
the CG was at 15"; with a 300lb. pilot, the CG was at 20". The axels were at
the leading edge of the wing. The plane had excellent ground handling and
flew well.
==================
Oscar Zuniga
San Antonio, TX
mailto: taildrags@hotmail.com
website at http://www.flysquirrel.net
Oscar Zuniga
San Antonio, TX
mailto: taildrags@hotmail.com
website at http://www.flysquirrel.net
Message 15
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d="scan'208,217"; a="1064122366:sNHT29667146"
Subject: | Carb heat on the Piet |
Oscar writes:
From: "Oscar Zuniga" <taildrags@hotmail.com>
> Chris- is this Greg and Dale's Piet (see photo)? If so, I'd like to know
> how the carb heat is working on it. My rebuilt exhaust stacks will be
> similar to this and I'm curious to know how well theirs works.
I meant to talk of this in the second pilot report. I get about a 20 rpm drop
when the carb heat is turned on so I would deem it inadequate in its present configuration.
I just looked at Bingelis' Firewall Forward, around pages 109 plus
or minus a few, and he is silent on the minimum rpm drop. My Cessna 140 gives
a 100 rpm drop at 1700 rpm. My Continental books all do not indicate a drop
required.
The way Greg and Dale's ship is set up, there is no "scooping" effect of the ram
air to force it through the heat muff which is stuffed with springs or something
to increase the surface area that the air can whip around as it warms up.
Without the scoop, it is only a suction effort of the motor to get air through
the muff. This suction effort, therfore, can suck through any other leaks
and cracks in the system, diluting the heating effect of what comes through the
muff. I believe that there should be positive, above ambient pressure in the
airbox whether the heat is on or off. This can only come with some attempt
at ram effect which exists with every small factory ship I can think of, most
taking the air pressure from the upper, pressurised plenum of the pressure cowl.
Look at the SIZE muff of what a Piper Cub or Taylorcraft has and use it as a guide. I also recommend a review of carb ice at William Wynne's Corvair site as he and Grace are now the authority on this subject since his accident. Call the hangar and talk to Grace, she will get all the answers. The website is www.flycorvair.com/carbice.html Read this all the way through noting the comments in the final paragraphs.
The current FAA approved operating manual, Form X30012, for the A, C and O-200
series from Continental reads, "The correct way to use carburetor heat is to
first apply full heat to remove any ice that has formed. Determine the minimum
amount of heat required to prevent ice forming, each time removing any ice that
has formed by applying full heat." It also states to use heat full on during
all ground operations as ice easily forms on the ground with the engine idling
with dire results upon takeoff. The carb heat should be on full "until the
throttle is advanced for the take-off run" which is when cold air is selected....
FAR 23.1093, advisory to us homebuilders, reads:
Sec. 23.1093
Induction system icing protection.
(a) Reciprocating engines. Each reciprocating engine air induction system must
have means to prevent and eliminate icing. Unless this is done by other means,
it must be shown that, in air free of visible moisture at a temperature of 30=B0
F.--
(1) Each airplane with sea level engines using conventional venturi carburetors
has a preheater that can provide a heat rise of 90=B0 F. with the engines at
75 percent of maximum continuous power;
The preceding applies to our carburated ships
Some irrelevent stuff omitted in this spot
(4) Each airplane with a sea level engine(s) using a fuel metering device tending
to prevent icing has a sheltered alternate source of air with a preheat of
not less than 60=B0F with the engines at 75 percent of maximum continuous power;
The preceding would apply to an Aerocarb or Ellsion equipped injected ship
(5) Each airplane with sea level or altitude engine(s) using fuel injection systems
having metering component on which impact ice may accumulate has a preheater
capable of providing a heat rise of 75=B0 F. with the engine is operating
at 75 percent of its maximum continuous power; and
(6) Each airplane with sea level or altitude engine(s) using fuel injection systems
not having fuel metering components projecting into the airstream on which
ice may form, and introducing fuel into the air induction system downstream
of any components or other obstruction on which ice produced by fuel evaporation
may form, has a sheltered alternate source of air with a preheat of not less
than 60=B0F with the engines at 75 percent of maximum continuous power.
The preceding applies to fuel injected ships
It appears that you would need a 90 degree rise on a a 30 degree day. Unfortunately,
they just tell what you need to have rather than the means to get there.
I am amazed that Bingelis is silent as well. How can he write abook called
Firewall Forward and not talk of such a value or goal to design to? It has to
be in there but I must not be seeing it.
Flitzer los!
Chris
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Subject: | flight testing Greg/Dale's plane |
--> Pietenpol-List message posted by: "Textor, Jack" <jtextor@thepalmergroup.com>
All,
Has anyone constructed a Piet with a "flying tail"? In my model days I
built several Sig Cadet Seniors. A great trainer, high wing, lot's of
dihedral, 80" wings. After the first one I built some airfoil into the
horizontal stabalizer and converted to conventional gear. It really
improved the flight characteristics.
Jack Textor
Des Moines
Message 17
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Subject: | Tailwheel control schemes |
Hi Rick:
Would like to see the pick of the tailwheel modification but get only a
thumbnail when trying to open with Windows XP and MS Picture It. A
repost would be appreciated. Thanks.
John Joyce
9 Sylvia Road
North Reading, MA 01864
978.664.3578
-----Original Message-----
From: owner-pietenpol-list-server@matronics.com
[mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Rick
Holland
Subject: Pietenpol-List: Tailwheel control schemes
After reading many archive messages about tailwheel control setup it
appears that many people have seen a need to make the tailwheel control
less sensitive than the rudder control. I am assuming I will want this
also so I figure its easier to build it in now that later. Have seen
many ingenious methods to do this but the 'Hanging two tubes off the
bellcrank tube' method in the attached photo seems to be the cleanest I
have found so far. And by placing multiple tabs or holes in the hanging
tubes the sensitivity can be easily changed. (Sorry I don't know the
name of the builder to give him credit).
Opinions?
--
Rick Holland
Castle Rock, CO
(Density altitude up to 8356 ft. currently, and its not even hot yet!)
Message 18
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|
Pieters
Are any you list regulars making plans to attend the SAA weekend, June 10,
11 12 at Urbana, Ill? It is not an advertised event. Membership is priced on
voluntary contributions. Of course you have to pay for the meals being served.
Should be a nice experience. Paul is trying to make SAA what EAA was about
55to 60. We are thinking about it but can't plan that far ahead.
Corky and Isabelle
Message 19
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|
s=s1024; d=yahoo.com;
b=C1PBRZCHq45SmJbwzk2NgMOaErdQncmy9GCbrllv2df2VZD1CtSFkS+CCwfRAgDo7b6nc3zOi2fTBZdOia7fSnc3A6LOeju1qGRIAVpNryngeX36Jsp0dWKpMWBU/LvtxiMrg6cjVhV3K0iDOeEjeG0WNd617VPmIybKEpyHvcI=
;
--> Pietenpol-List message posted by: Larry Nelson <lnelson208@yahoo.com>
If the WX allows me to fly, I will be there in Bonanza
V-35B N2980A, camping by my plane. Pietenpol N444MH
will have to stay home.
--- Isablcorky@aol.com wrote:
> Pieters
>
> Are any you list regulars making plans to attend the
> SAA weekend, June 10,
> 11 12 at Urbana, Ill? It is not an advertised event.
> Membership is priced on
> voluntary contributions. Of course you have to pay
> for the meals being served.
> Should be a nice experience. Paul is trying to make
> SAA what EAA was about
> 55to 60. We are thinking about it but can't plan
> that far ahead.
>
> Corky and Isabelle
>
Larry Nelson
Springfield, MO
Beechcraft Bonanza V-35B N2980A
Pietenpol Air Camper N444MH
1963 GMC 4106-1618
SV/ Spirit of America
ARS WB0JOT
Message 20
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|
Subject: | Grove Wheels/Brakes |
It's shopping time for wheels, brakes, tires, & master cylinders and there is a
large price savings with Grove's.
What advice can you all give?
Message 21
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s=s1024; d=yahoo.com;
b=4hMQn6C9n0vhs0hK5xPjINHJgSfqtejf5BKpFk7sU4EevohvwGKtRyisxk+Q1MzsJ8U6e1HC798ZdmyR+RBjwPI98HaY2WUC8S5MHMlY2Z1Y7+EkDK2qrohBF4KBaRL19iU9SK+hgNv9FYviKy7LE78ISGg6IQaeCbvk4CvspXQ=
;
--> Pietenpol-List message posted by: Galen Hutcheson <wacopitts@yahoo.com>
Half gallon milk jugs work great! Make sure the
bottom of the bottle is pointed downward (or put the
plane in a dive) to prevent having to fly around until
your pants dry. :)
Doc
--- Michael D Cuy <Michael.D.Cuy@grc.nasa.gov> wrote:
> --> Pietenpol-List message posted by: Michael D Cuy
> <Michael.D.Cuy@grc.nasa.gov>
>
> sure makes it easier to pee in a bottle by steering
> with your feet while
> your hands
> are busy. Beats stopping for fuel when you don't
> have to on an x-country
> and wasting 45 minutes:)
>
> Mike C.
>
>
>
>
>
>
> browse
> Subscriptions page,
> FAQ,
>
>
>
>
>
>
>
>
>
>
Message 22
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d="scan'208,217"; a="981089871:sNHT30629186"
Corky,
I went two years ago. Might make it depending on what the airline wants to do
with me.
Chris
Braumeister und Inspektor der Flitzer und Flitzermotoren
----- Original Message -----
From: Isablcorky@aol.com
To: pietenpol-list@matronics.com
Sent: Wednesday, June 01, 2005 5:54 PM
Subject: Pietenpol-List: Urbana
Pieters
Are any you list regulars making plans to attend the SAA weekend, June 10, 11
12 at Urbana, Ill? It is not an advertised event. Membership is priced on voluntary
contributions. Of course you have to pay for the meals being served. Should
be a nice experience. Paul is trying to make SAA what EAA was about 55to
60. We are thinking about it but can't plan that far ahead.
Corky and Isabelle
Message 23
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Subject: | Re: Cork float fuel-proof varnish? |
In a message dated 6/1/2005 2:15:40 PM Central Standard Time,
steve@wotelectronics.com writes:
I am replacing the cub-style fuel guage rod in my plane, and would like to
re-coat the cork while I have it out. There are a few chips in the existing
varnish, and I want to make sure it doesn't start absorbing fuel and sink
in-flight, as I've been told this can happen.
Steve,
I built both my tanks using fiberglass and Polyester Resin (auto body stuff).
Problem is that any alcohol in the fuel could soften up the resin. For this
reason, I coated my float with polyester resin to fuel proof it, as well as
use it as a monitor for any softening effect of accidental alcohol in the fuel.
Chuck G.
Message 24
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Subject: | Re: Second Pilot report |
Chris,
You have posted some very informative info for all to see !!
Just a little note:
you said -
This had the effect of increasing the attack angle of the stabiliser making
it more agressive in holding the nose up.
To be specific, the angle of incidence is the angle between the Mean
Aerodynamic Chord of the airfoil and the longitude line, or 'Thrust Line' of the
airframe. Thus, lowering the leading edge of the stabilizer, Decreases the angle
of Incidence of the stab. This also decreases the angle of attack of the
stab, thus pushing down on the tail - thus Increasing the Angle of Attack of the
Wing. Angle of Attack is the angle between the MAC and the Relative Wind.
2000 rpm cruise is a pretty good range, and is the same as on my plane. A
difference in just 100 rpm effects pitch attitude for reasons you stated. This
is a typical Pietenpol Characteristic. Some of these things you just have to
accept as design characteristics, such as the Straight Wing as opposed to
Dihedral. I prefer straight wing, as designed. Neutral Thrust Glide sounds like
you have most of the wing heavy, and pitch problems worked out. Right Rudder
in cruise is due to torque, and if you adjust it out by shimming the engine
mount, it will probably show up in another way. Nothing is free. I just rest
my right foot on the rudder bar, and live with it. Hardly noticeable in
cruise, until I lift my foot off the rudder bar, causing a left yaw.
you said -
She has so much drag on final that pulling the power to idle and pointing
agressively down will give a good rate of descent at a constant airspeed so slips
to landing should not be often necessary.
This is true, but it's a good thing to practice, to prepare for squeezing
into a very short landing field, in case of an emergency.
If the engine mount was long enough to get rid of that 60 lbs of ballast, the
ship will handle MUCH better !!
Chuck Gantzer
NX770CG
Message 25
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d="scan'208,217"; a="342106960:sNHT1228576680"
"Paul Shenton" <paul@pjshenton.go-plus.net>
Subject: | We mean the same thing |
Chuck,
We are both trying to say the same thing. If you are the stab and you were having
a good day and were talking to the engineer who was designing you, you might
suggest to him that he use an airfoil shape and have the airfoil inverted as
it would then have the greatest effect. The stab holds the nose up by it providing
lift DOWN. Just as I increase the angle of attack of the big wing by
raising its leading edge, I increase the angle of attack of the stabilizer by
lowering its leading edge.
Look at an old Fleet and you will see exactly what not to do. Look at a handful
of Waco Model 10s that were lucky enough to come with an airfoil shaped stab
and you will see exactly what to do.
Formal definitions aside, this is was it going on with all the lifties....and now
Oscar has a grasp on a concept new to him.
As for the 60 pounds of ballast, Greg and I plan a reweigh so that we can determine
a couple of things not done the first time around (when I was not there although
Greg is a big proponent of this). We will run ship level tail up weight
numbers with occupants in one then both cockpits in order to determine the
true CG of each seat with a live person in the seat(s) rather than estimating
the position of the CG of each occupant. This should dial in some really good
numbers to make sure we are not penalising ourselves by assuming a too far aft
position of the occupant's own CG.
Likewise, we will run weight numbers with the aircraft in a taildown position with
one then both seats occupied by the same "dummies" and, after noting the angle
the ship sits at, we can run a little math that will enable us to determine
the true vertical CG of the ship. This final exercise is all to widen the
knowledge base of the user group.
Cheers,
Chris,
Chris
Braumeister und Inspektor der Flitzer und Flitzermotoren
----- Original Message -----
From: Rcaprd@aol.com
To: pietenpol-list@matronics.com
Sent: Thursday, June 02, 2005 12:51 AM
Subject: Re: Pietenpol-List: Second Pilot report
Chris,
You have posted some very informative info for all to see !!
Just a little note:
you said -
This had the effect of increasing the attack angle of the stabiliser making it
more agressive in holding the nose up.
To be specific, the angle of incidence is the angle between the Mean Aerodynamic
Chord of the airfoil and the longitude line, or 'Thrust Line' of the airframe.
Thus, lowering the leading edge of the stabilizer, Decreases the angle
of Incidence of the stab. This also decreases the angle of attack of the stab,
thus pushing down on the tail - thus Increasing the Angle of Attack of the Wing.
Angle of Attack is the angle between the MAC and the Relative Wind.
2000 rpm cruise is a pretty good range, and is the same as on my plane. A difference
in just 100 rpm effects pitch attitude for reasons you stated. This
is a typical Pietenpol Characteristic. Some of these things you just have to
accept as design characteristics, such as the Straight Wing as opposed to Dihedral.
I prefer straight wing, as designed. Neutral Thrust Glide sounds like
you have most of the wing heavy, and pitch problems worked out. Right Rudder
in cruise is due to torque, and if you adjust it out by shimming the engine mount,
it will probably show up in another way. Nothing is free. I just rest my
right foot on the rudder bar, and live with it. Hardly noticeable in cruise,
until I lift my foot off the rudder bar, causing a left yaw.
you said -
She has so much drag on final that pulling the power to idle and pointing agressively
down will give a good rate of descent at a constant airspeed so slips
to landing should not be often necessary.
This is true, but it's a good thing to practice, to prepare for squeezing into
a very short landing field, in case of an emergency.
If the engine mount was long enough to get rid of that 60 lbs of ballast, the
ship will handle MUCH better !!
Chuck Gantzer
NX770CG
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