Today's Message Index:
----------------------
1. 02:47 AM - Re: Thrust lines (Patrick Ladd)
2. 08:40 AM - Re: Thrust lines (B Young)
3. 09:45 AM - Re: Thrust lines (Bill Berle)
4. 10:07 AM - Re: Thrust lines (Bill Berle)
5. 10:14 AM - Re: Thrust lines (John Hauck)
6. 10:26 AM - Re: Thrust lines (John Hauck)
7. 03:22 PM - Re: Thrust lines (mojavjoe@comcast.net)
8. 03:38 PM - Re: Thrust lines (Bill Berle)
Message 1
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| Subject: | Re: Thrust lines |
Hi Rick,
I think the discussion had gone beyond just the mounting of the HKS into th
e general behaviour of engines mounted away from the centre line of the a/c
.i.e. most pushers. Obviously the closer to the centre line the better but
the effects of the high thrust line can be minimised (but not eliminated)
by changing the angle of the thrust, hence my suggestion of tipping the eng
ine slightly by adding washers. I remember flying a pretty little biplane
amphibian in France on the Gulf de Morbihan many years ago. The prop was mo
unted like the Kolb as a high pusher to keep it out of the spray when landi
ng in the sea. The pilot was at great pains to explain the importance of se
tting up the engine at the correct angle which was NOT parallel to the flig
ht line. Set up wrongly full chat at takeoff could stuff your nose into the
water.
As an aside. I met that pilot by accident at Sun `n` Fun a couple of years
later. The flying world is very small.
Ok ,I have stopped digging
Cheers
Pat
________________________________
From: owner-kolb-list-server@matronics.com <owner-kolb-list-server@matronic
s.com> on behalf of Rick Neilsen <neilsenrm@gmail.com>
Sent: 21 September 2016 16:31:23
Subject: Re: Kolb-List: Thrust lines
Pat
Bill asked the question about mounting his HKS. This engine isn't a real co
mmon engine yet. It was a good question. The correct answer is mount it as
low as you can for the best all around performance. A washer or two doesn't
help when the prop is too high, tried that also.
We have a saying in this country...your digging a hole for your self, quit
digging.
Please please do not archive
Rick Neilsen
On Wed, Sep 21, 2016 at 5:17 AM, Patrick Ladd <patrickjladd@hotmail.com<mai
lto:patrickjladd@hotmail.com>> wrote:
Oh dear, I didn`t mean to stir up such a furore.
My comments applied to a properly set up machine. If you cannot get off the
ground or climb at full chat with normal control inputs then there is some
thing wrong with the machine . The thrust line, which can be adjusted by a
few washers is an easy option. is the weight and balance correct is another
. Sorry if I sound as if I am teaching grannie to suck eggs but if you hav
e to throttle back to takeoff then the basics are very wrong. Pat
Message 2
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| Subject: | Re: Thrust lines |
Pat
If the pusher engine is not mounted in line with flight, did you raise
the front or the back to eliminate the nose over tendency? Also that is
the trim difference in straight and level flight, with the front raised vs
having the back raised????
Boyd
...........................
The prop was mounted like the Kolb as a high pusher to keep it out of the
spray when landing in the sea. The pilot was at great pains to explain the
importance of setting up the engine at the correct angle which was NOT
parallel to the flight line. Set up wrongly full chat at takeoff could
stuff your nose into the water.
Pat
Message 3
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| Subject: | Re: Thrust lines |
On Thu, 9/22/16, Patrick Ladd <patrickjladd@hotmail.com> wrote:
"Set up wrongly full chat at takeoff could stuff your nose into the water."
As an aside, completely separate from the thrust line discussion... the last time
I saw the expression "full chat" used, I believe it was in an article written
by the great British racing and test pilot Ranald Porteous, regarding his experiences
in the incredible little Chilton Monoplane. Every time I see that old
black and white picture of him just strutting along down the flight line, holding
the tailskid of the Chilton in his hand, it makes me smile. What a time
to have been in aviation ! Thanks to Roy Nerou for keeping the Chilton legacy
alive :)
OK... back to Kolbs. I intend to mount my engine in such a way as to put the thrust
line as low as practicable. I am very happy that the cumulative knowledge
and field experience and the members of this discussion group seems to strongly
support this concept.
Bill Berle
FireStar 2 / HKS 700E being mounted
Los Angeles
Message 4
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| Subject: | Re: Thrust lines |
The concept on high mounted engines (Lake Buccaneer and others) is to angle the
thrust line so that the wind from the propeller is blowing downward a little
onto the stabilizer. This pushes the back end of the airplane downward a little,
which (hopefully) compensates for the engine trying to push the nose down.
The Kolb ALREADY has a little of this built in, you can see it very easily. The
bottom of the propeller arc is further forward (closer to the steel cage) than
the top of the propeller arc. Homer Kolb and/or the other designers/engineers
on the project built that angle in to the airplane, based on well known and
proven principles. They were smart to do it, and it worked. I'm guessing that
the angle built into the Kolb fuselage is correct for the originally installed
engines, which is why it is always reported that the original "stock" Kolb flies
perfectly. Makes perfect sense. Homer did it right.
If you are adding a lot more power to the aircraft (or raising the thrust line
because of a redrive), adding washers under the front of the engine mounts will
raise the front of the engine, INCREASING the downward angle of the prop airflow
as it hits the tail, and pushing down on the tail a little more. There is
nothing wrong with trying to adjust the thrust line this way, so long as it doesn't
allow the propeller tip to get too close to the tailboom, or the rear of
the steel cage.
HOWEVER, the height of the thrust line (above the CG) will have a lot more effect
on the airplane than the angle blowing down on the tail.... so there is only
so much you can do with washers, and it easily may not be enough to overcome
the "leverage" of the engine trying to push the nose down.
Bill Berle
www.ezflaphandle.com - safety & performance upgrade for light aircraft
www.grantstar.net - winning proposals for non-profit and for-profit entities
--------------------------------------------
On Thu, 9/22/16, B Young <byoungplumbing@gmail.com> wrote:
Subject: Re: Kolb-List: Thrust lines
To: kolb-list@matronics.com
Date: Thursday, September 22, 2016, 8:40 AM
Pat
If the pusher engine is not mounted in line with
flight, did you raise the front or the back to
eliminate the nose over tendency? Also that is the trim
difference in straight and level flight, with the front
raised vs having the back raised????
Boyd
...........................
The prop was mounted like the Kolb as a high
pusher to keep it out of the spray when landing in the sea.
The pilot was at great pains to explain the importance of
setting up the engine at the correct angle which was NOT
parallel to the flight line.Set up wrongly full chat at
takeoff could stuff your nose into the water.
Pat
Message 5
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Boyd Y/Kolbers:
Early on I experimented with changing the thrust line, both up and down,
front and rear, with as much as 5/8ths inch difference from stock
position. After a lot of wrenching and flying, I put things back to
where they belonged. I found no difference in airspeed, pitch trim, or
anything else.
Much like my experiments with the leading edge of the upper vertical
stabilizer. After a lot of drilling and riveting difference positions
to try and counteract adverse yaw, I ended up back where I started.
Homer and Dennis did a good job designing the MKIII original.
john h
mkIII
Rock House, Oregon
From: owner-kolb-list-server@matronics.com
[mailto:owner-kolb-list-server@matronics.com] On Behalf Of B Young
Sent: Thursday, September 22, 2016 9:40 AM
Subject: Re: Kolb-List: Thrust lines
Pat
If the pusher engine is not mounted in line with flight, did you
raise the front or the back to eliminate the nose over tendency? Also
that is the trim difference in straight and level flight, with the
front raised vs having the back raised????
Boyd
...........................
The prop was mounted like the Kolb as a high pusher to keep it out of
the spray when landing in the sea. The pilot was at great pains to
explain the importance of setting up the engine at the correct angle
which was NOT parallel to the flight line. Set up wrongly full chat at
takeoff could stuff your nose into the water.
Pat
Message 6
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As I was reading my msg below, not only did I think of another
experiment I did, I also noticed I misspelled "different".
To counteract adverse yaw on my original Firestar I elongated the engine
mounting holes to allow me to twist the engine and change the thrust
line laterally. That experiment didn't prove anything either, but cost
me a new mounting plate.
john h
mkIII
Rock House, Oregon
From: owner-kolb-list-server@matronics.com
[mailto:owner-kolb-list-server@matronics.com] On Behalf Of John Hauck
Sent: Thursday, September 22, 2016 11:15 AM
Subject: RE: Kolb-List: Thrust lines
Boyd Y/Kolbers:
Early on I experimented with changing the thrust line, both up and down,
front and rear, with as much as 5/8ths inch difference from stock
position. After a lot of wrenching and flying, I put things back to
where they belonged. I found no difference in airspeed, pitch trim, or
anything else.
Much like my experiments with the leading edge of the upper vertical
stabilizer. After a lot of drilling and riveting difference positions
to try and counteract adverse yaw, I ended up back where I started.
Homer and Dennis did a good job designing the MKIII original.
john h
mkIII
Rock House, Oregon
From: owner-kolb-list-server@matronics.com
[mailto:owner-kolb-list-server@matronics.com] On Behalf Of B Young
Sent: Thursday, September 22, 2016 9:40 AM
Subject: Re: Kolb-List: Thrust lines
Pat
If the pusher engine is not mounted in line with flight, did you
raise the front or the back to eliminate the nose over tendency? Also
that is the trim difference in straight and level flight, with the
front raised vs having the back raised????
Boyd
...........................
The prop was mounted like the Kolb as a high pusher to keep it out of
the spray when landing in the sea. The pilot was at great pains to
explain the importance of setting up the engine at the correct angle
which was NOT parallel to the flight line. Set up wrongly full chat at
takeoff could stuff your nose into the water.
Pat
Message 7
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| Subject: | Re: Thrust lines |
It seemed to me that this discussion started about raising the HKS engine to clear
the exhaust on one side. Couldn't those washers be used on that one side to
raise it the required distance while raising the thrust line only half that
distance.
Joe
----- Original Message -----
From: "John Hauck" <jhauck@elmore.rr.com>
Sent: Thursday, September 22, 2016 1:25:45 PM
Subject: RE: Kolb-List: Thrust lines
As I was reading my msg below, not only did I think of another experiment I did,
I also noticed I misspelled "different".
To counteract adverse yaw on my original Firestar I elongated the engine mounting
holes to allow me to twist the engine and change the thrust line laterally.
That experiment didn't prove anything either, but cost me a new mounting plate.
john h
mkIII
Rock House, Oregon
From: owner-kolb-list-server@matronics.com [mailto:owner-kolb-list-server@matronics.com] On Behalf Of John Hauck
Sent: Thursday, September 22, 2016 11:15 AM
Subject: RE: Kolb-List: Thrust lines
Boyd Y/Kolbers:
Early on I experimented with changing the thrust line, both up and down, front
and rear, with as much as 5/8ths inch difference from stock position. After a
lot of wrenching and flying, I put things back to where they belonged. I found
no difference in airspeed, pitch trim, or anything else.
Much like my experiments with the leading edge of the upper vertical stabilizer.
After a lot of drilling and riveting difference positions to try and counteract
adverse yaw, I ended up back where I started.
Homer and Dennis did a good job designing the MKIII original.
john h
mkIII
Rock House, Oregon
From: owner-kolb-list-server@matronics.com [ mailto:owner-kolb-list-server@matronics.com ] On Behalf Of B Young
Sent: Thursday, September 22, 2016 9:40 AM
Subject: Re: Kolb-List: Thrust lines
Pat
If the pusher engine is not mounted in line with flight, did you raise the front
or the back to eliminate the nose over tendency? Also that is the trim difference
in straight and level flight, with the front raised vs having the back raised????
Boyd
...........................
The prop was mounted like the Kolb as a high pusher to keep it out of the spray
when landing in the sea. The pilot was at great pains to explain the importance
of setting up the engine at the correct angle which was NOT parallel to the
flight line. Set up wrongly full chat at takeoff could stuff your nose into the
water.
Pat
Message 8
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| Subject: | Re: Thrust lines |
Apparently the aileron interference problem is solved by moving the aileron one
way or another during assembly, so it is now a non-issue. I will be going out
to the hangar this evening to test that theory !
Bill Berle
www.ezflaphandle.com - safety & performance upgrade for light aircraft
www.grantstar.net - winning proposals for non-profit and for-profit entities
--------------------------------------------
On Thu, 9/22/16, mojavjoe@comcast.net <mojavjoe@comcast.net> wrote:
Subject: Re: Kolb-List: Thrust lines
To: "kolb-list" <kolb-list@matronics.com>
Date: Thursday, September 22, 2016, 3:21 PM
It seemed to me that this
discussion started about raising the HKSengine to clear
the exhaust on one side. Couldn't those washers be used
on that oneside to raise it the required distance while
raising the thrust line only half that distance.
Joe
From: "John
Hauck" <jhauck@elmore.rr.com>
To: "kolb-list"
<kolb-list@matronics.com>
Sent:
Thursday, September 22, 2016 1:25:45 PM
Subject: RE: Kolb-List: Thrust lines
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#yiv7640047964 As I was reading my msg below, not
only did I think of another experiment I did, I also noticed
I misspelled "different".To counteract adverse yaw on my
original Firestar I elongated the engine mounting holes to
allow me to twist the engine and change the thrust line
laterally. That experiment
didn't prove anything either, but cost me a new mounting
plate.john hmkIIIRock House,
OregonFrom:
owner-kolb-list-server@matronics.com
[mailto:owner-kolb-list-server@matronics.com] On Behalf Of John
Hauck
Sent: Thursday,
September 22, 2016 11:15 AM
To:
kolb-list@matronics.com
Subject: RE: Kolb-List:
Thrust linesBoyd
Y/Kolbers:Early on I experimented with
changing the thrust line, both up and down, front and rear,
with as much as 5/8ths inch difference from stock
position. After a lot of wrenching
and flying, I put things back to where they belonged. I found no difference in
airspeed, pitch
trim, or anything else.Much like my experiments with the
leading edge of the upper vertical stabilizer. After a lot of drilling and riveting
difference positions to try and counteract adverse yaw, I
ended up back where I started.Homer and Dennis did a good job
designing the MKIII original.john hmkIIIRock House,
OregonFrom: owner-kolb-list-server@matronics.com
[mailto:owner-kolb-list-server@matronics.com]
On Behalf Of B
Young
Sent: Thursday,
September 22, 2016 9:40 AM
To: kolb-list@matronics.com
Subject: Re: Kolb-List:
Thrust linesPat
If the pusher
engine is not mounted in line with flight, did you
raise the front or the back to eliminate the nose over
tendency? Also that is the trim difference in straight and
level flight, with the front raised vs having the back
raised????Boyd...........................The prop was mounted like the Kolb
as a high pusher to keep it out of the spray when landing in
the sea. The pilot was at great pains to explain the
importance of setting up the engine at the correct angle
which was NOT parallel to the flight line.Set up wrongly
full chat at takeoff could stuff your nose into the
water.
Pat
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