Today's Message Index:
----------------------
1. 01:02 AM - horsepower (Clif Dawson)
2. 05:30 AM - Re: Pitch Trimming (FTLovley@AOL.COM)
3. 05:43 AM - flying at 19 or 20" of aft CG (Michael D Cuy)
4. 05:51 AM - Re: flying at 19 or 20" of aft CG (Phillips, Jack)
5. 09:01 AM - Re: flying at 19 or 20" of aft CG (Gordon Bowen)
6. 09:39 AM - Re: flying at 19 or 20" of aft CG (Phillips, Jack)
7. 10:48 AM - spar testing (Oscar Zuniga)
8. 01:54 PM - Re: Pitch Trimming (GCARDINAL@mn.rr.com)
9. 03:43 PM - Re: Pitch Trimming (Ed G.)
10. 11:30 PM - Re: Pitch Trimming (Rcaprd@aol.com)
Message 1
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Play with this for a while boys;
http://www.tc.gc.ca/CivilAviation/Regserv/Affairs/cars/Part5/Standards/549/sub-b.htm#549.109
Also in combo with 111 right below it.
The Vimy is now in Toronto! Now that's one huge Pietenpol!
Clif, controls almost done;
http://clifdawson.ca/Pietenpol4.html
There is nothing, absolutely nothing, half as much worth doing
as simply messing about in airplanes! ( Wind In The Willows )
Message 2
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Subject: | Re: Pitch Trimming |
--> Pietenpol-List message posted by: FTLovley@aol.com
Chris...be really carefull while flying a Continental powered Pietenpol with
its extra forward side area while having a CG at 20 inches aft of the leading
edge. It will probably fly just fine, but if you spin it , you will be in
deep do-do. They are even worse if the landing gear V's are covered with fabric,
increasing the forward area. Also, be careful slipping the airplane close to
the ground, as they can sometimes take extra time to recover. I've been away
from the Piets for a while, but my memory is still good, and I learned some
of this stuff the hard way. I had 1000 hours in Pietenpols before I was old
enough to vote, but that was back when I was bullet proof and invisible. Fly
Safe...
Forrest Lovley
Message 3
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Subject: | flying at 19 or 20" of aft CG |
--> Pietenpol-List message posted by: Michael D Cuy <Michael.D.Cuy@grc.nasa.gov>
Starts getting light in the nose at about 20" aft CG and I have to hold
forward
stick at 21". The stab should be in line with the top longerons. You
should not
have to mess with that. Something doesn't add up.
Mike C.
Message 4
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Subject: | flying at 19 or 20" of aft CG |
--> Pietenpol-List message posted by: "Phillips, Jack" <jphillip@alarismed.com>
I agree with you, Mike. My Piet has the long fuselage, 65 Continental,
wire wheels. At CG 20" aft of the LE, I have to hold a little forward
stick, even with full nose down trim. I will shim the leading edge of
the stabilizer up a little more when I finish the rebuild.
Jack Phillips
-----Original Message-----
--> Pietenpol-List message posted by: Michael D Cuy
<Michael.D.Cuy@grc.nasa.gov>
Starts getting light in the nose at about 20" aft CG and I have to
hold
forward
stick at 21". The stab should be in line with the top longerons. You
should not
have to mess with that. Something doesn't add up.
Mike C.
Message 5
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Subject: | Re: flying at 19 or 20" of aft CG |
--> Pietenpol-List message posted by: "Gordon Bowen" <gbowen@ptialaska.net>
Flying on the back edge of CG limit is an invitation to a tail heavy
(non-recoverable) stall. Most everyone should have to hold a little nose
down/stick forward pressure at 20" aft loaded CG, but if normally operating
in the back side of the CG envelope while still below gross limit, I think
any builder should consider moving around some heavy stuff inside the plane
to get their loaded CG forward to 15"-17" aft of LE wing.. It's common in
a lot of other homebuilts to build a "pocket" somewhere forward or aft to
hold extra bags of lead shot. The pilot determines when they need to add
more shot when flying alone or with a non-standard load. All Longezes,
Variezes and Cozys have a pocket in the nose to add lead shot so a
lightweight pilot cannot get into a tail heavy (repeat repeat
NON-RECOVERABLE) stall.
Gordon Bowen -Homer Alaska
Cozy IV N64CY
Osprey II N64SY
Pietenpol N-1033B
" But such is the constitution of my mind I cannot avoid forming an
opinion", John Adams
----- Original Message -----
From: "Phillips, Jack" <jphillip@alarismed.com>
Subject: RE: Pietenpol-List: flying at 19 or 20" of aft CG
> --> Pietenpol-List message posted by: "Phillips, Jack"
<jphillip@alarismed.com>
>
> I agree with you, Mike. My Piet has the long fuselage, 65 Continental,
> wire wheels. At CG 20" aft of the LE, I have to hold a little forward
> stick, even with full nose down trim. I will shim the leading edge of
> the stabilizer up a little more when I finish the rebuild.
>
> Jack Phillips
>
> -----Original Message-----
> --> Pietenpol-List message posted by: Michael D Cuy
> <Michael.D.Cuy@grc.nasa.gov>
>
> Starts getting light in the nose at about 20" aft CG and I have to
> hold
> forward
> stick at 21". The stab should be in line with the top longerons. You
>
> should not
> have to mess with that. Something doesn't add up.
>
> Mike C.
>
>
Message 6
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Subject: | flying at 19 or 20" of aft CG |
--> Pietenpol-List message posted by: "Phillips, Jack" <jphillip@alarismed.com>
I agree Gordon. However, extensive stalls (I have not spun it, yet)
show the plane recovers quickly and easily. I have read that
undercambered wings like the Pietenpol can be flown at further aft cg's
than more "normal" airfoils. My centersection fuel tank does not change
the CG much as fuel burns off, but what change there is tends to move
the CG forward. I don't think a pilot that weighs more than my 200 lbs
should fly it without adding ballast in the baggage compartment.
After the rebuild the CG situation should be much improved. My new axle
is 8 lbs heavier than the original, and I am using the BHP coil spring
tailwheel design in place of the leafspring type I had before, which
saves a whopping 1-1/2 lbs at the tail. Both should help shift the CG
forward a bit.
Jack Phillips
NX899JP
-----Original Message-----
From: owner-pietenpol-list-server@matronics.com
[mailto:owner-pietenpol-list-server@matronics.com] On Behalf Of Gordon
Bowen
Subject: Re: Pietenpol-List: flying at 19 or 20" of aft CG
--> Pietenpol-List message posted by: "Gordon Bowen"
<gbowen@ptialaska.net>
Flying on the back edge of CG limit is an invitation to a tail heavy
(non-recoverable) stall. Most everyone should have to hold a little
nose
down/stick forward pressure at 20" aft loaded CG, but if normally
operating
in the back side of the CG envelope while still below gross limit, I
think
any builder should consider moving around some heavy stuff inside the
plane
to get their loaded CG forward to 15"-17" aft of LE wing.. It's common
in
a lot of other homebuilts to build a "pocket" somewhere forward or aft
to
hold extra bags of lead shot. The pilot determines when they need to
add
more shot when flying alone or with a non-standard load. All Longezes,
Variezes and Cozys have a pocket in the nose to add lead shot so a
lightweight pilot cannot get into a tail heavy (repeat repeat
NON-RECOVERABLE) stall.
Gordon Bowen -Homer Alaska
Cozy IV N64CY
Osprey II N64SY
Pietenpol N-1033B
" But such is the constitution of my mind I cannot avoid forming an
opinion", John Adams
----- Original Message -----
From: "Phillips, Jack" <jphillip@alarismed.com>
Subject: RE: Pietenpol-List: flying at 19 or 20" of aft CG
> --> Pietenpol-List message posted by: "Phillips, Jack"
<jphillip@alarismed.com>
>
> I agree with you, Mike. My Piet has the long fuselage, 65
Continental,
> wire wheels. At CG 20" aft of the LE, I have to hold a little forward
> stick, even with full nose down trim. I will shim the leading edge of
> the stabilizer up a little more when I finish the rebuild.
>
> Jack Phillips
>
> -----Original Message-----
> --> Pietenpol-List message posted by: Michael D Cuy
> <Michael.D.Cuy@grc.nasa.gov>
>
> Starts getting light in the nose at about 20" aft CG and I have to
> hold
> forward
> stick at 21". The stab should be in line with the top longerons.
You
>
> should not
> have to mess with that. Something doesn't add up.
>
> Mike C.
>
>
Message 7
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--> Pietenpol-List message posted by: "Oscar Zuniga" <taildrags@hotmail.com>
Dave asked-
>How did you do your testing?
There is another (simple) methodology on my website, at
http://www.flysquirrel.net/wing/spartest.html
Oscar Zuniga
San Antonio, TX
mailto: taildrags@hotmail.com
website at http://www.flysquirrel.net
Message 8
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Subject: | Re: Pitch Trimming |
--> Pietenpol-List message posted by: GCARDINAL@mn.rr.com
Chuck,
Changing power does not affect the nose down tendency. It is something
aerodynamic.
Please send picture of your trim tab.
Thanks, Greg
----- Original Message -----
From: Rcaprd@aol.com
Subject: Re: Pietenpol-List: Pitch Trimming
> Adjusting the leading edge of the horiz stab down, does
> indeed help the
> nose down pitch tendency. I adjusted mine down on three different
> occasions,
> lengthening the top turnbuckles by 2 turns, and tightening the
> bottom ones by
> 2 turns. Each time it helped, but didn't cure it. Standing in
> front of the
> plane, you could see the leading edge of the stab, how it curved
> down on each
> side. I finally added a fixed trim tab on the elevators
> (flippers). I made
> it from balsa wood, blending the trailing edge of the flippers
> into the trim
> tabs. Each is about 5" long, and have a chord of about 2" and
> angled down about
> 10. Initially, I tested the positon of the trim tab holding it
> on with duct
> tape. When I was satisfied with the placement, I used fabric &
> paint for the
> final install. With these trim tabs, I was able to remove all the
> leading
> edge down adjustments of the horiz stab, and now the stab is
> straight. I could
> take some pictures of it if you're interested.
> I believe some of the pitch down tendency when you pull power,
> can be
> attributed to the drag of the landing gear. Does it climb with
> full power, and
> no back pressure on the stick ? I would also suggest you check
> the symatry
> again, as well as wing washout - doesn't take much time.
>
>
Message 9
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Subject: | Re: Pitch Trimming |
--> Pietenpol-List message posted by: "Ed G." <flyboy_120@hotmail.com>
Hi Everyone...If my waneing memory serves me right Corky posted that on his
test flights that he had to twist the leading edge of his Stabilizer down
three times until he cured his nose down tendency...Now Greg is haveing a
similar problem and Chuck comes back and says that he had to add a trim tab
for the same reason...I havent installed my lower rudder hinge yet so there
is still time to ask a question that I really struggled with when building
my Horiz. Stab....I built my stab. with the center line parralell to the
upper longerons because that is what some trusted people on the list said it
should be...Reading the plans carefully shows that the leading edge should
be up more than 1/16" beacuse; The trailing edge member is 1" thick and the
narrow section where the 3/16" plywood sits is 5/8" ( the plywood sits flush
with the 1")...The center beam is 3/4" thick with 3/16" ply top and bottom;
3/4' + 3/16"+ 3/16" = 1 1/8" ....Divideing by two to get the center line =
9/16" at the center beam and 1/2' at the trailing edge. this would put the
center beam's C/L 1/16" higher than the trailing edge and the leading edge
slightly higher yet...Sooo...if you build to the plans the the stabilizer's
C/L is NOT parallel to the upper longeron but raised at the front...So my
question is; Did Corky, Chuck and Greg build theirs to the plans or did they
build them parallel to the longerons?? This will help those of us who are
still building get a better idea of what the incidence should be...If theirs
were parallel maybe we should build in adjustments to drop ours even more if
needed and if they built theirs to the plans we might be okay....
thanks in advance...Ed Grentzer assembleing
my engine and fuel system
>From: GCARDINAL@mn.rr.com
>Reply-To: pietenpol-list@matronics.com
>To: pietenpol-list@matronics.com
>Subject: Re: Pietenpol-List: Pitch Trimming
>Date: Thu, 26 May 2005 15:54:40 -0500
>
>--> Pietenpol-List message posted by: GCARDINAL@mn.rr.com
>
>Chuck,
>Changing power does not affect the nose down tendency. It is something
>aerodynamic.
>Please send picture of your trim tab.
>
>Thanks, Greg
>
>----- Original Message -----
>From: Rcaprd@aol.com
>Date: Wednesday, May 25, 2005 11:57 pm
>Subject: Re: Pietenpol-List: Pitch Trimming
> > Adjusting the leading edge of the horiz stab down, does
> > indeed help the
> > nose down pitch tendency. I adjusted mine down on three different
> > occasions,
> > lengthening the top turnbuckles by 2 turns, and tightening the
> > bottom ones by
> > 2 turns. Each time it helped, but didn't cure it. Standing in
> > front of the
> > plane, you could see the leading edge of the stab, how it curved
> > down on each
> > side. I finally added a fixed trim tab on the elevators
> > (flippers). I made
> > it from balsa wood, blending the trailing edge of the flippers
> > into the trim
> > tabs. Each is about 5" long, and have a chord of about 2" and
> > angled down about
> > 10. Initially, I tested the positon of the trim tab holding it
> > on with duct
> > tape. When I was satisfied with the placement, I used fabric &
> > paint for the
> > final install. With these trim tabs, I was able to remove all the
> > leading
> > edge down adjustments of the horiz stab, and now the stab is
> > straight. I could
> > take some pictures of it if you're interested.
> > I believe some of the pitch down tendency when you pull power,
> > can be
> > attributed to the drag of the landing gear. Does it climb with
> > full power, and
> > no back pressure on the stick ? I would also suggest you check
> > the symatry
> > again, as well as wing washout - doesn't take much time.
> >
> >
>
>
Message 10
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Subject: | Re: Pitch Trimming |
It seems to me you have some aerodynamic stuff going on here. I have to
assume Greg & Dale built the fwd cabane struts 1" longer than the aft ones.=20
This sets the wing at approximately 3=BA positive incidence. That's according
to
plans...no matter if they are all lengthened a couple of inches. However, if
there is a great deal of washout in both wings, this will cause a nose down
tendency. Also, if the wing is not square with the fuse, it will cause a roll
tendency, especially with too much washout...that's why I suggested
re-checking symmetry and washout. Rig the wing by measuring from the exact=20same
spot of
each wing tip, to a point in the center of the fuselage (aft edge of turtle
deck), just ahead of the leading edge of the horiz / vert stab. Make a dot
with a sharpie pen, to measure to. In fact, I do it from two different points
on
the wing - one at the outboard trailing edge of the wing, ahead of the
aileron, and another time at the inboard end of the aileron, trailing edge of the
wing. Not the aileron, but the wing. Two people with a tape measure stretched
tight, and it only takes a couple of minutes. Record your measurements on the
sketch of a plan view of the plane. To check for washout, level the
longerons for & aft and left & right, and use a 4 foot level (confirm the level
reads
the same both sides up) at a point on the bottom of the rib, just outboard of
the cabane struts. Note the gap at the fwd end of the level. Measure again
at the lift strut attachment, then again at the tip rib. Record all these
measurements. Very little washout is all you need - maybe 1/8" at the very=20most.
Just so you err on the side of washout, and it's the same amount on both
sides. Sit down and study the measurements. If you have to change the symmetry,
it will change the washout also. You will have to loosen all the lift strut
bolts, cabane strut bolts, and jury strut bolts to change the symmetry. Then
you have to re-check and re-adjust the washout. Record every measurement, date
& time, you take. I think your gremlins are in the rigging. Check it all,
and chase 'em out !!
The other things that inherently cause nose down pitch is the pendulum
effect of parasitic drag, the negative pitching moment of an undercambered
airfoil, and the actual mass of the flippers being behind the hinge line.
Adjusting the leading edge of the stab down maybe 2 or 3 turns on the
turnbuckles, and go fly. You can even raise the trailing edge up about one=20or
two turns on the turnbuckles. This is an effective method to trim the nose=20up,
but you need to use small increments between flights.
How far back is the wing from vertical ? I think you should take
advantage of the unique design feature of the Pietenpol, in that you can move your
wing aft, to bring the CG forward to a safer range. It would likely require
making some new cables, but re-terminate the long ones, to use them on the short
side. Like others have said to guard against an aft CG...it just simply
gives me the Hiebie Jiebies !!
Adding ballast also gives me the Hiebie Jiebies - that's why I made the
engine mount on my plane so long. My wing is 3 1/2" aft of vertical, and with
my 210 - 215 lbs. of fat butt in there, the C.G. is just under 20" aft of
Leading Edge of the wing, even with Zero fuel in both tanks. The Hard Line, No
More Aft C.G. is 20" aft of Leading Edge - No Excuses !!
Adding ballast in the front seat does very little to effect the CG. I
doubt if 100 lbs would move it more than 1/8" forward. If you can't possibly
move the wing aft, and you don't want to build a new engine mount, cowling,=20and
everything else, here is one suggestion:
Cast a couple of long Lead ingots (using shotgun shot) to fit the outer
diameter of the lower tubes on the engine mount. Use thin rubber strips to=20isolate
them from the steel tubes, and isolate some type of clamp, to keep from
scratching the paint off the engine mount. This could possibly even reduce=20the
vibration of the engine from being transmitted to the fuselage. Another option
is using a metal prop.
Greg - I'll get a couple of low resolution pictures of my trim tabs
tomorrow, and post them to the group. I'm very satisfied with these trim tabs,
because they work well holding the nose up aerodynamically, as opposed to a=20bunji
chord method of pulling on the top elevator cable. And like I said, I was
able to re-adjust the horizontal stabilizer back to neutral and flat. I
couldn't shim the aft edge of the horizontal stab up, because my ship was complete
and flying, and I already had the lower rudder hinge located.
Chuck Gantzer
NX770CG
I spent 45 minutes playing in the pattern this evening, shooting
landings. I used an abbreviated pattern, but still got up to over 600' agl=20on
downwind, turn base early, pull power to 1500 and let the nose drop to maintain
65
mph. On base leg, I pull power almost all the way to idle and slip it down=20past
the cones at the beginning of the runway to about 10', but I maintained above
65 mph the whole way down. Very steep decent. My landing gear Vee's are NOT
covered. Easily comes out of the slip, align right up with the runway, and
it bleeds of speed like she had a drag chute !! Before anyone ever tries this
so close to the ground, you need a properly rigged ship, and become VERY
familiar with your ship at 2500 or 3000 agl.
I was also practicing a unique takeoff. Clear the runway, hold brakes
tight, full power, smoke ON, lots of forward stick, lift the tail off the ground
before beginning to roll, drag the brakes for the first 50 feet so the tail
wouldn't come back down, then let 'er go !! Ya can't practice this one from
2500' agl :)
Two hot air balloons took off about 100 feet from my hanger.
What an Excellent evening !!
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