Today's Message Index:
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1. 04:44 AM - Re: SV: Re: KIS IT-1 Aerodynamics - Julians mod ()
2. 09:22 AM - Re: SV: Re: KIS IT-1 Aerodynamics - Julians mod (Mark Kettering)
3. 11:41 AM - Re: KIS IT-1 Aerodynamics - Main wheel location (Hans Christian Erstad)
4. 12:00 PM - Re: Re: KIS IT-1 Aerodynamics - Main wheel location (JOHN JACKSON)
Message 1
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Subject: | Re: KIS IT-1 Aerodynamics - Julians mod |
7/7/2010
Hello Hans Christian, Thank you for this input and the very interesting
picture attached -- it may be seen here:
http://forums.matronics.com/viewtopic.php?t=72540
It reveals a point regarding the KIS TR-1C tail dragger that I did not know
before -- that is the junction relationship of the upper end of the main
landing gear strut fairing, the fuselage, and the inboard wing leading edge.
The RV-8 people make a fuss over the effect on their airplane's aerodynamics
of the upper main landing gear strut fairing at that same fuselage junction.
Some RV-8 builders have put a small curved strake just forward of this
junction to shape the airflow. See a picture about one third down this page:
http://www.rv8.ch/index.php?topic=General
It looks like Julian has no fairing or strake at all at that junction so
some of his airplane's aerodynamics may be affected by this fact.
'OC' Baker Says: "The best investment we can make is the time and effort to
gather and understand knowledge."
PS: Hello Julian, Even though you may no longer be subscribed to the
Matronics Kis listing you may want to go to the KIS archives and take a look
at all the KIS TR-1 aerodynamics related posts over the last month or so.
======================================================================
----- Original Message -----
From: "Hans Christian Erstad" <hans-chr.erstad@c2i.net>
Sent: Tuesday, July 06, 2010 4:26 AM
Subject: SV: SV: KIS-List: Re: KIS IT-1 Aerodynamics - Julians mod
Tim
Yes, Julians was a tail dragger, and he was operating from what I would call
"STOL fields". He is now building a GlaStar, and he is not on this forum
anymore?
I have encosed a picture I took of Julians plane in 2004 at Stauning,
Denmark.
I should have taken the photo from the rear, to show the fairing from that
angle.
In my understaning, the fairing can start with a small radius at the leading
endge, and should increase the radius toward the rear. Julian had what
looked like a constant radius.
But as Mark comment - and I also agree on - is that we want some warning of
"close to stall condition". Apparently Lancair have a bad stall-crach
record, and Lancair owners I know have installed AOA system with audible
warning. ("ear-shaker" instead of stick-shaker?)
Again, regards, Hans Christian
Message 2
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Subject: | Re: KIS IT-1 Aerodynamics - Julians mod |
Hi OC,
I also noticed that the gear leg to fuselage junction was not faired and was thinking
this would be draggy. But now that you mentioned it I agree this could
be a cause of problems at the wing root on the upper surface at high AOA. This
could also explain why my nose dragger does not exhibit the same problem.
Mark
>
>It reveals a point regarding the KIS TR-1C tail dragger that I did not know
>before -- that is the junction relationship of the upper end of the main
>landing gear strut fairing, the fuselage, and the inboard wing leading edge.
>
>The RV-8 people make a fuss over the effect on their airplane's aerodynamics
>of the upper main landing gear strut fairing at that same fuselage junction.
>Some RV-8 builders have put a small curved strake just forward of this
>junction to shape the airflow. See a picture about one third down this page:
>
>http://www.rv8.ch/index.php?topic=General
>
>It looks like Julian has no fairing or strake at all at that junction so
>some of his airplane's aerodynamics may be affected by this fact.
>
Message 3
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Subject: | Re: KIS IT-1 Aerodynamics - Main wheel location |
Hello Mark
Your wrote: "Next time you fly please try this for me but be very careful
and let me know what happens!"
I went flying today, and on takeoff I held the stick back just enough to
lift the nose wheel and take off. I held the stick in that position for a
while (2-3 seconds?). The nose became too high and speed too low. Just as
you predicted.
I have not really noticed this, but apparently I always reduce stick back
pressure when the airplane lifts off, to keep pich angle more or less
constant, and low enough for the speed to increase.
Landing again, I can keep the nose wheel from comming down immediately after
landing, and can keep it raised for the first 50-100 meters or so. With CG
at max fwd position, I need to be concentrated to manage this. If I land at
a short runway, I let the nosewheel come down, in order to start braking.
Regards, Hans Christian
-----Opprinnelig melding-----
Fra: owner-kis-list-server@matronics.com
[mailto:owner-kis-list-server@matronics.com] P vegne av Mark Kettering
Sendt: 5. juli 2010 20:18
Til: kis-list@matronics.com
Emne: Re: SV: KIS-List: Re: KIS IT-1 Aerodynamics
Hello Hans,
>I have flown my KIS 1 for 10 years now, and I agree with 'OC' comments
>about the handling with respect to difficulties making consistent
>landings and keeping the nose wheel up.
I have flown a TR1 with the main gear in the stock position and with that
aircraft I also had the same problems. So I made some calculations and
found out that the stock main gear location was too far aft. On my TR1 I
then moved it forward and fully eliminated not only this problem on my
aircraft but also the takeoff tendency to over rotate. When flying with
Rich and watching the stick I noted that he had to pull way back to rotate
then quickly release this back force and movement to prevent over rotation
on lift off.
>About the wing/fuselage fairing. I have meet Julian several times at
>fly-in. He told that the fairing modification made the landings with a
>low approach speed a lot easier. Why not believe his experience? I
>think he is the only one to make the modification, and having
>experiencd what difference it makes. I have fairing modification on my
>to-do list. But I may never come to that item on my list, as I feel the
>landings are still OK, and I do not operate from runways shorter than
>800 meters. I usually keep a little power on in the flare.
Well, I am not a believer! But that has little to do with Julian's
experiences. More to do with science and engineering methods. At some
point with more data I may agree that the elevator loses authority due to
wing fuselage junction separation. At this point I am waiting on seeing the
video for myself. The one still picture I have seen does not seem to
support the conclusion that the wing fuselage junction is causing separation
of flow over the tail. I also never have a sudden loss or any loss of
elevator authority with my aircraft at any time and I have the stock wing
root fairings so this data also does not seem to support that conclusion.
But this is not to say that Julian did not have this problem. Maybe his
plane is slightly different than mine. Maybe my more poor (or maybe better)
fit of my parts in this area prevented a problem that his plane had. Who
knows?
But I do do know the stock main gear location is too far aft relative to the
CG (range) location. I also know that angling the gear forward (moving the
gear contact point forward) reduces the hard nose let down at all CG
locations and cures the tendency to over rotate.
Next time you fly please try this for me but be very careful and let me know
what happens! As you pull back to rotate just hold the stick in the same
location and fly off the runway. This is how a good handling aircraft
should takeoff. It should not need pilot input beyond a steady back
pressure. You should not need to release or push forward. The plane should
literally "fly itself" off the runway. But if you do this in the TR1 with
the main gear in the stock location you will over rotate and need to move
the stick forward. Or you will stall and maybe worse.
Also please keep in mind that the gear location is very easy to change.
Thanks,
Mark
Message 4
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Subject: | Re: KIS IT-1 Aerodynamics - Main wheel location |
Hello all=0A=0AI'm not sure if-this is-worth anything to the discussion
but there's a video on =0Ayoutube of my TR-1 landing on a short grass stri
p last weekend.=0A=0Ahttp://www.youtube.com/watch?v=ZZz2DuQXACo&feature
=related- at 8minutes 48 =0Aseconds onwards.=0A=0AI hold the power at a
bout 1200rpm until the very late, short flare.- The nose =0Awheel could h
ave been held off but I let it lower early to begin braking.- I =0Athen h
ad to pick it up again to cross a small track that I'd not noticed until
=0Aquite late in the landing.=0A=0AI was one-up with about 30ltrs of fuel a
nd needed about 350m on the downslope to =0Acome to a halt.=0A=0AJJ=0A=0A
=0A=0A=0A________________________________=0AFrom: Hans Christian Erstad <ha
ns-chr.erstad@c2i.net>=0ATo: kis-list@matronics.com=0ASent: Wednesday, 7 Ju
ly, 2010 19:39:55=0ASubject: KIS-List: Re: KIS IT-1 Aerodynamics - Main whe
=0A<hans-chr.erstad@c2i.net>=0A=0AHello Mark=0A=0AYour wrote: "Next time yo
u fly please try this for me but be very careful=0Aand let me know what hap
pens!" =0A=0AI went flying today, and on takeoff I held the stick back just
enough to=0Alift the nose wheel and take off. I held the stick in that pos
ition for a=0Awhile (2-3 seconds?).- The nose became too high and speed t
oo low.- Just as=0Ayou predicted.=0A=0AI have not really noticed this, bu
t apparently I always reduce stick back=0Apressure when the airplane lifts
off, to keep pich angle more or less=0Aconstant, and low enough for the spe
ed to increase. =0A=0ALanding again, I can keep the nose wheel from comming
down immediately after=0Alanding, and can keep it raised for the first 50-
100 meters or so.- With CG=0Aat max fwd position, I need to be concentrat
ed to manage this.- If I land at=0Aa short runway, I let the nosewheel co
me down, in order to start braking.=0A=0ARegards, Hans Christian=0A=0A-----
Opprinnelig melding-----=0AFra: owner-kis-list-server@matronics.com=0A[mail
to:owner-kis-list-server@matronics.com] P=E5 vegne av Mark Kettering=0ASend
t: 5. juli 2010 20:18=0ATil: kis-list@matronics.com=0AEmne: Re: SV: KIS-Lis
ering <mantafs@earthlink.net>=0A=0AHello Hans,=0A=0A>I have flown my KIS 1
for 10 years now, and I agree with 'OC' comments =0A>about the handling wit
h respect to difficulties making consistent =0A>landings and keeping the no
se wheel up.=0A=0AI have flown a TR1 with the main gear in the stock positi
on and with that=0Aaircraft I also had the same problems.- So I made some
calculations and=0Afound out that the stock main gear location was too far
aft.- On my TR1 I=0Athen moved it forward and fully eliminated not only
this problem on my=0Aaircraft but also the takeoff tendency to over rotate.
- When flying with=0ARich and watching the stick I noted that he had to p
ull way back to rotate=0Athen quickly release this back force and movement
to prevent over rotation=0Aon lift off.=0A=0A>About the wing/fuselage fairi
ng.- I have meet Julian several times at =0A>fly-in.- He told that the
fairing modification made the landings with a =0A>low approach speed a lot
easier. Why not believe his experience? I =0A>think he is the only one to m
ake the modification, and having =0A>experiencd what difference it makes.
- I have fairing modification on my =0A>to-do list. But I may never come
to that item on my list, as I feel the =0A>landings are still OK, and I do
not operate from runways shorter than =0A>800 meters. I usually keep a litt
le power on in the flare.=0A=0AWell, I am not a believer!- But that has l
ittle to do with Julian's=0Aexperiences.- More to do with science and eng
ineering methods.- At some=0Apoint with more data I may agree that the el
evator loses authority due to=0Awing fuselage junction separation. At this
point I am waiting on seeing the=0Avideo for myself.- The one still pictu
re I have seen does not seem to=0Asupport the conclusion that the wing fuse
lage junction is causing separation=0Aof flow over the tail.- I also neve
r have a sudden loss or any loss of=0Aelevator authority with my aircraft a
t any time and I have the stock wing=0Aroot fairings so this data also does
not seem to support that conclusion.=0A=0ABut this is not to say that Juli
an did not have this problem.- Maybe his=0Aplane is slightly different th
an mine.- Maybe my more poor (or maybe better)=0Afit of my parts in this
area prevented a problem that his plane had.- Who=0Aknows?=0A=0ABut I do
do know the stock main gear location is too far aft relative to the=0ACG (r
ange) location.- I also know that angling the gear forward (moving the=0A
gear contact point forward) reduces the hard nose let down at all CG=0Aloca
tions and cures the tendency to over rotate.=0A=0ANext time you fly please
try this for me but be very careful and let me know=0Awhat happens!- As y
ou pull back to rotate just hold the stick in the same=0Alocation and fly o
ff the runway.- This is how a good handling aircraft=0Ashould takeoff.-
It should not need pilot input beyond a steady back=0Apressure.- You sho
uld not need to release or push forward.- The plane should=0Aliterally "f
ly itself" off the runway.- But if you do this in the TR1 with=0Athe main
gear in the stock location you will over rotate and need to move=0Athe sti
ck forward.- Or you will stall and maybe worse.=0A=0AAlso please keep in
mind that the gear location is very easy to change.=0A=0AThanks,=0AMark=0A
=========================0A
=================
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