Today's Message Index:
----------------------
1. 08:43 AM - Re: MkIII Xtra (Richard Girard)
2. 09:27 AM - Re: MkIII Xtra (Mike Welch)
3. 11:15 AM - Re: MkIII Xtra (Richard Girard)
4. 11:29 AM - Re: Re: MkIII Xtra (NeilsenRM@gmail.com)
5. 02:16 PM - Re: Bi-Fold Aircraft Doors (Dennis Thate)
6. 03:01 PM - Re: Re: MkIII Xtra (Richard Girard)
7. 04:30 PM - Re: Re: MkIII Xtra (william sullivan)
Message 1
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The reference to my talk with Bryan was poorly stated for the information I
was trying to convey. What I was trying to say was that lowering the wing
incidence works to negate the downward pressure exerted by the "X" fuselage
pod, that several builders have done them incorrectly and welding up the
holes and remounting them solved the problem.
So, I got up before dawn, made final adjustments to the flaps to eyeball
them in to being equal side to side, and went flying. It was done sans any
center gap seal at all. The wings are now so low that the old one can't be
hacked up to even mount it much less offer any kind of drag reduction.
Immediately after take off I was disappointed to find that there was little
improvement in pitch. As I passed over the departure end of the runway and
started searching the pattern just in case someone else was up early to come
visiting, I noticed that I had neglected to pull on any trim. Pulling the
trim handle meant slipping out of my shoulder harness to reach it (I fly
right seat) and once adjusted, which yielded a small improvement in back
pressure on the stick, I couldn't refasten the buckle. This was now going to
be a flight around the pattern, rather than the slightly longer one to get a
little more altitude and try nudging up to stall speed to see how optimistic
the airspeed indicator is, that I had planned.
Being a windy morning, I started my turn to base from abeam the runway end,
made my turn and slid along at a roughly 45 degree angle to my actual
direction of travel until it was time to turn final. I was quite high, but I
counted on the wind gradient to give me a steep approach angle even without
flaps and at 600 feet and roughly about the same from the end of the runway,
I pulled the power to idle. SURPRISE!, all the back pressure went away. As a
glider, the airplane is now completely neutral. Landing number seven was the
most pleasant I've made in Ken's airplane. While I still kept the airspeed
up to 60 indicated, I was able to relax my death grip on the stick and, for
a few seconds at least, enjoy flying the aircraft.
So, the change to wing incidence seems to have alleviated the negative lift
of the "platypus nose" fuselage pod and it appears I'm dealing with a thrust
line issue.
John H., if you're reading this, try not to say "I told you so". He did, by
the way, so I deserve it.
Anyway, even though the engine is 5/16" lower than the factory mounting for
a 618 with the "E" gearbox, the combination of the extra height, 70"
propeller, and changed thrust line from the IIIC seems to be the cause of
the nose down pitch attitude.
Here are the angles as they are since I moved the wing incidence, adjusted
for the motor mount being level.
Left and Right wing 2.8 degrees
Boom 7 degrees
H Stab 7 degrees
There are some small changes in the readings of the boom and horizontal
stabilizers since the ones I took last. I measured each twice this time,
rotating the protractor 180 degrees in the horizontal plane and taking the
average of the two measurements.
As a firm believer in doing the cheapest "fix" first, I'm going to lower the
front of the motor mount to change the thrust angle by the difference
between the C and X wing incidence.
It's not forecast to be flyable, at least for test flying, again until
Thursday at dawn so I'll know more then.
On Mon, Jun 6, 2011 at 9:10 PM, Mike Welch <mdnanwelch7@hotmail.com> wrote:
> Rick,
>
> I was only relaying the factory recommended numbers that Bryan says, not
> suggesting
> a particular solution in your case. You are infinitely more qualified to
> know how to handle
> what your situation requires than me. I'm just an interested observer
> who's trying to find
> some very valuable information.
>
> I got lost in your explanation *"He assured me that he had welded up
> holes before that *
> *were drilled so as to set the wing incidence too high and it had fixed
> the problem." *I did
> not understand what you were getting at. ???
>
> If you have the horizontal stabs set right down the middle of the boom
> tube, then that means
> they are essentially -6.1 degrees (or real close) Since there is no
> adjustment of the boom
> tube angle of -6.1 degrees....compared to the motor mount, obviously
> something parallel to it
> would be the same. Now, maybe this helps make the plane fly better, but
> it sure does NOT
> sound like the angles I've been led to believe are correct for an Xtra.
> Bryan told me those
> numbers I posted. If they don't work very well on Ken's plane, I think I'd
> be doing some
> serious investigating.
>
> I still say......"sumptin's up!!"
>
> Maybe we could get an Xtra owner/flyer to share what his angles and W&B
> information is.
> There's nothing like having someone tell us all what works GREAT for him.
> Plus, it might
> give a good indication why that stab has to be so low, compared to the OEM
> setting.
>
> *How about it, Xtra owners, anybody have the digital incidences and
> angles, and the W&B on a *
> *decent flying plane??*
>
> BTW, it would seem to me that lowering the main wings' incidence down to
> their proper angle,
> would make the plane even more nose heavy. At least, that's how I would *
> think* it would act.
> I look forward to a successful pirep!!
>
> Mike Welch
>
>
> ------------------------------
> Date: Mon, 6 Jun 2011 17:57:50 -0500
>
> Subject: Re: Kolb-List: MkIII Xtra
> From: aslsa.rng@gmail.com
> To: kolb-list@matronics.com
>
> Mike, All I can tell you is that the horizontal stabs are now set right
> down the center of the boom. I started out with them in the upper most hole
> of the bracket and moved them down in steps to try and relieve the nose
> heaviness. Lower was better in each step to the lowest position.
> It was Bryan that suggested I lower the wings to the lowest setting. I was
> concerned about being able to get the aircraft to rotate. He assured me that
> he had welded up holes before that were drilled so as to set the wing
> incidence too high and it had fixed the problem.
> Since I have the CG at the almost the farthest aft position, 34.28% (I use
> 35% as most aft), and I'm running the trim in the most up position, I don't
> think less horizontal stabilizer incidence is the way to go.
> The nice thing about having a flying aircraft is that theory can be tested
> against reality PDQ. With any luck, I'll know in the morning.
>
> Rick
>
>
> *
>
>
> *
>
>
--
Zulu Delta
Mk IIIC
Thanks, Homer GBYM
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
Message 2
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Rick=2C
Sounds like you're on the right path. Good luck on your next attempt to
get it fixed.
I am curious=2C before you change the existing thrust line=2C can you che
ck what the present
angle is? You could probably figure an accurate way to do it=2C but maybe
using a
large rectangle of cardboard=2C with your protractor taped in place 90 degr
ees from the
edge you line up with the prop blades.
Aslo=2C can you measure the EXACT height of the propeller centerline to t
he boom tube? I'm
curious how my GEO motor prop centerline measures up against the Rotax 582.
Mike Welch
out in my shop today painting blue & yellow accent stripes
high 90's heat and humidity is rough!!!
Message 3
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Mike, The thrust line, barring flex of the Lord mounts is right down the
engine mount. There are no shims installed at this time. The center of the
prop is 36" above the top of the boom tube.
Rick
On Tue, Jun 7, 2011 at 11:24 AM, Mike Welch <mdnanwelch7@hotmail.com> wrote:
> Rick,
>
> Sounds like you're on the right path. Good luck on your next attempt to
> get it fixed.
>
> I am curious, before you change the existing thrust line, can you check
> what the present
> angle is? You could probably figure an accurate way to do it, but maybe
> using a
> large rectangle of cardboard, with your protractor taped in place 90
> degrees from the
> edge you line up with the prop blades.
>
> Aslo, can you measure the EXACT height of the propeller centerline to the
> boom tube? I'm
> curious how my GEO motor prop centerline measures up against the Rotax 582.
>
> Mike Welch
> out in my shop today painting blue & yellow accent stripes
> high 90's heat and humidity is rough!!!
>
>
> *
>
> *
>
>
--
Zulu Delta
Mk IIIC
Thanks, Homer GBYM
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
Message 4
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Rick/All
I had a long discussion with Brian M at Sun-N-Fun before the tornado hit.
He said that the early xtras had a larger horizontal stabilizer to
compensate for what they later found was down pressure on the nose from
flying nose low. Reducing the wing incidence fixed the problems and
increased speeds.
Now for the downward pitching problem I will suggest one more time that you
get that trim system working properly. You may need to add a spring or
change to a heaver one. Just keep playing with it till it flies level.
Flying solo you should be near the low end of pitch trim adjustment so that
you will have plenty more trim when you have a heavy passenger. Go ahead
and play with the thrust angle but that, according to John H, it will have
little impact. For best performance set the thrust angle to level in level
flight.
I set my trim for hands off for cruise. I fine tune the trim by adding or
reducing power a bit. Kolbs with high thrust engines change the pitch trim
it is the nature of the beast. I find that pitch trim at cruise power or
low power with one notch of flaps on approach is about the same pitch trim.
Rick Neilsen
Redrive VW Powered MKIIIC
On , Mike Welch <mdnanwelch7@hotmail.com> wrote:
> Rick,
> Sounds like you're on the right path. Good luck on your next attempt to
> get it fixed.
> I am curious, before you change the existing thrust line, can you check
> what the present
> angle is? You could probably figure an accurate way to do it, but maybe
> using a
> large rectangle of cardboard, with your protractor taped in place 90
> degrees from the
> edge you line up with the prop blades.
> Aslo, can you measure the EXACT height of the propeller centerline to the
> boom tube? I'm
> curious how my GEO motor prop centerline measures up against the Rotax
> 582.
> Mike Welch
> out in my shop today painting blue & yellow accent stripes
> high 90's heat and humidity is rough!!!
Message 5
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| Subject: | Re: Bi-Fold Aircraft Doors |
We have been battling high winds and high heat all week. Hope to get the bi/fold
installed this weekend....note the trees bending over in the background.
--------
Both optimists and pessimists contribute to our society. The optimist invents
the airplane and the pessimist the parachute. ~Gil Stern
Faith is believing what you know ain't so - Mark Twain
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=342339#342339
Attachments:
http://forums.matronics.com//files/dsc01664_119.jpg
Message 6
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Rick, So far as I can tell, without putting a force gage on the elevator,
the trim system is working properly, at least compared to my Mk III.
I was up at Jabara Airport in Wichita today and got to talking with the
pilot of a Piaggio Avanti II turboprop. On the way home I got to thinking
that If changing the thrust line doesn't work I'm going to make a composite
canard and fasten it to the end of the fuselage truss. By my calculations
about an 8' span should give just the required lift. Ken will have the first
three lifting surface control Kolb.
Rick
On Tue, Jun 7, 2011 at 1:27 PM, <NeilsenRM@gmail.com> wrote:
> Rick/All
>
> I had a long discussion with Brian M at Sun-N-Fun before the tornado hit.
> He said that the early xtras had a larger horizontal stabilizer to
> compensate for what they later found was down pressure on the nose from
> flying nose low. Reducing the wing incidence fixed the problems and
> increased speeds.
>
> Now for the downward pitching problem I will suggest one more time that you
> get that trim system working properly. You may need to add a spring or
> change to a heaver one. Just keep playing with it till it flies level.
> Flying solo you should be near the low end of pitch trim adjustment so that
> you will have plenty more trim when you have a heavy passenger. Go ahead and
> play with the thrust angle but that, according to John H, it will have
> little impact. For best performance set the thrust angle to level in level
> flight.
>
> I set my trim for hands off for cruise. I fine tune the trim by adding or
> reducing power a bit. Kolbs with high thrust engines change the pitch trim
> it is the nature of the beast. I find that pitch trim at cruise power or low
> power with one notch of flaps on approach is about the same pitch trim.
>
> Rick Neilsen
> Redrive VW Powered MKIIIC
>
>
> On , Mike Welch <mdnanwelch7@hotmail.com> wrote:
> >
> >
> >
> >
> >
> > Rick,
> >
> >
> >
> > Sounds like you're on the right path. Good luck on your next attempt
> to get it fixed.
> >
> >
> >
> > I am curious, before you change the existing thrust line, can you check
> what the present
> >
> > angle is? You could probably figure an accurate way to do it, but maybe
> using a
> >
> > large rectangle of cardboard, with your protractor taped in place 90
> degrees from the
> >
> > edge you line up with the prop blades.
> >
> >
> >
> > Aslo, can you measure the EXACT height of the propeller centerline to
> the boom tube? I'm
> >
> > curious how my GEO motor prop centerline measures up against the Rotax
> 582.
> >
> >
> >
> > Mike Welch
> >
> > out in my shop today painting blue & yellow accent stripes
> >
> > high 90's heat and humidity is rough!!!
> >
> >
> >
> >
> >
> >
> =====================
> >
> >
> >
>
> *
>
> *
>
>
--
Zulu Delta
Mk IIIC
Thanks, Homer GBYM
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- Groucho Marx
Message 7
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- A Kolb bi-plane!!!
-
do not archive
--- On Tue, 6/7/11, Richard Girard <aslsa.rng@gmail.com> wrote:
From: Richard Girard <aslsa.rng@gmail.com>
Subject: Re: RE: Kolb-List: MkIII Xtra
Rick, So far as I can tell, without putting a force gage on the elevator, t
he trim system is working properly, at least compared to my Mk III.
I was up at Jabara Airport in Wichita today and got to talking with the pil
ot of a Piaggio Avanti II turboprop. On the way home I got to thinking that
If changing the thrust line doesn't work I'm going to make a composite can
ard and fasten it to the end of the fuselage truss. By my calculations abou
t an 8' span should give just the required lift. Ken will have the first th
ree lifting surface control Kolb.
Rick-
On Tue, Jun 7, 2011 at 1:27 PM, <NeilsenRM@gmail.com> wrote:
Rick/All
I had a long discussion with Brian M at Sun-N-Fun before the tornado hit. H
e said that the early xtras had a larger horizontal stabilizer to compensat
e for what they later found was down pressure on the nose from flying nose
low. Reducing the wing incidence fixed the problems and increased speeds.
Now for the downward pitching problem I will suggest one more time that you
get that trim system working properly. You may need to add a spring or cha
nge to a heaver one. Just keep playing with it till it flies level. Flying
solo you should be near the low end of pitch trim adjustment so that you wi
ll have plenty more trim when you have a heavy passenger. Go ahead and play
with the thrust angle but that, according to John H, it will have little i
mpact. For best performance set the thrust angle to level in level flight.
I set my trim for hands off for cruise. I fine tune the trim by adding or r
educing power a bit. Kolbs with high thrust engines change the pitch trim i
t is the nature of the beast. I find that pitch trim at cruise power or low
power with one notch of flaps on approach is about the same pitch trim.
Rick Neilsen
Redrive VW Powered MKIIIC
On , Mike Welch <mdnanwelch7@hotmail.com> wrote:
>
>
>
>
>
> Rick,
>
> -
>
> - Sounds like you're on the right path.- Good luck on your next attem
pt to get it fixed.
>
> -
>
> - I am curious, before you change the existing thrust line, can you che
ck what the present
>
> angle is?-- You could probably figure an accurate way to do it, but m
aybe using a
>
> large rectangle of cardboard, with your protractor taped in place 90 degr
ees from the
>
> edge you line up with the prop blades.
>
> -
>
> - Aslo, can you measure the EXACT height of the-propeller centerline
to the boom tube?- I'm
>
> curious how my GEO motor prop centerline measures up against the Rotax 58
2.
>
> -
>
> Mike Welch
>
> out in my shop today painting blue & yellow accent stripes--
>
> high 90's heat and humidity is-rough!!!
> -
>
> -
>
>
>
=====================
>
>
>
get="_blank">http://www.matronics.com/Navigator?Kolb-List
tp://forums.matronics.com
_blank">http://www.matronics.com/contribution
--
Zulu Delta
Mk IIIC
Thanks, Homer GBYM
It isn't necessary to have relatives in Kansas City in order to be unhappy.
- - Groucho Marx
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