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BlueSkyFlier
Joined: 27 Jan 2011
Posts: 74
Location: UK
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 Posted: Fri Apr 08, 2011 9:07 am Post subject: Re: Landing the KIS TR-1 |
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In an earlier posting Graham enquired about the actual airfoil profile for the TR-1. Attached herewith a diagram which can be used for that purpose to a very close approximation.
It is a comparison between the 63(2)-215 [in red] and 63(2)A-015 profile [in green] with identical chord length.
For all practical purposes the TR-1 wing profile could be considered to match the red outline for the left half of the chord and then follow the green outline for the rear section of the chord.
This diagram can be accessed at: http://www.worldofkrauss.com/foils/show_compare?sform_contains=63%282%29&items_per_page=50&commit=Compare&id[]=1416&id[]=1688
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| Description: |
| This diagram can be accessed at: http://www.worldofkrauss.com/foils/show_compare?sform_contains=63%282%29&items_per_page=50&commit=Compare&id[]=1416&id[]=1688 |
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bakerocb
Joined: 15 Jan 2006
Posts: 727
Location: FAIRFAX VA
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| Posted: Fri Apr 08, 2011 9:38 am Post subject: Landing the KIS TR-1 |
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4/8/2011
Hello Mark, You wrote:
1) "Has this ever happened to anyone?"
Absolutely. This is what has generated the majority of the initial postings
on the subject of "how to land the KIS TR-1". Pilots were surprised /
frightened by a sudden nose drop after they had started the landing flare at
what they considered an acceptable approach airspeed.
2) "I think that if this has happened it was due to normal stalling of the
wing ......"
Because these surprised / frightened pilots had started the landing flare
with an acceptable approach airspeed they began to search for explanations
for the sudden nose drop other than, or in addition to, "... normal stalling
of the wing...". In the course of this search there have been many postings
on subjects such as:
A) Inadequate wing-to-fuselage fairing diameter creating a burble as the
nose is raised during the landing flare. This burble flows back to the
horizontal tail surfaces and suddenly reduces those surface's down force.
Julian Bone extensively researched this characteristic by installing yarn
tufts and video taping them. He subsequently significantly modified his
wing-to-fuselage fairings.
B) Inadequate elevator surface area / pitch authority. This characteristic
was recognized early on and several builders subsequently extended the
trailing edges of their airplane's elevator.
C) More recently Alfred has been focusing on KIS TR-1 wing airfoil
characteristics to explain this sudden nose drop phenomena.
3) ".... work to prevent it by watching airspeed and AOA."
I don't know of very many pilots that watch airspeed readings during the
landing flare and then use those readings to control pitch attitude.
I don't know of very many KIS TR-1 airplanes that are equipped with angle of
attack indicators and I don't know of many pilots that would use changing
angle of attack indications during the landing flare to control pitch
attitude.
I think that what most pilots use during the landing flare to adjust their
pitch attitude is what they see by looking out of the canopy and comparing
what they see, both in terms of pitch attitude and distance above the
landing surface, with what they think is acceptable to see.
The consensus that I see arising out of the many postings on the subject of
"how to land the KIS TR-1" is that nose high pitch attitudes close to the
landing surface is not a good idea and can result in unpleasant nose drop
surprises. The KIS TR-1 is not your father's Cessna 172 when it comes to the
landing flare.
4) "I am not so sure this is just a nuisance. When a nose gear breaks due
to repeated slamming it could get very expensive."
That is exactly my clarification issue. A nose gear can contact the landing
surface when the pilot really doesn't want it to under three circumstances:
A) The pilot flys his approach at such an excessive airspeed and low pitch
attitude that the nose gear is the first thing to contact the landing
surface. This has not been an issue in our previous postings.
B) The pilot touches down at an acceptable attitude after an appropriate
approach airspeed and landing flare, but the design of the airplane, main
landing gear placement, inadequate pitch authority, or some factor causes
the nose gear to contact, not slam onto, the landing surface. This falls
into the nuisance or annoyance category because the pilot could not
initially aerodynamically brake as he wished to.
C) The nose gear does indeed slam into the landing surface, either at the
same time as the main landing gear contacts the landing surface or a
fraction of a second after main landing gear contact, because the airplane's
pitch attitude has abruptly changed nose down when the pilot did not expect
it to and too quickly for him to avoid nose gear slam. This is what some
pilots landing the KIS TR-1 have experienced and they then searched for a
reason and a solution in this forum.
My posting was intended to differentiate between B and C and the
significance of those two events regarding safe operations when landing the
KIS TR-1.
'OC' Baker Says: "The best investment we can make is the time and effort to
gather and understand knowledge."
==============================================
From: "Mark Kettering" <mantafs(at)earthlink.net>
To: <kis-list(at)matronics.com>
Sent: Friday, April 08, 2011 11:31 AM
Subject: Re: Re: Landing the KIS TR-1
| Quote: |
>However I would like to clarify and emphasize that:
>
>A) The danger / discomfort of having the nose abruptly drop while still
>airborne and close to the landing surface, and
Has this ever happened to anyone? If so was it caused by stalling the
wing? If so was this due to "normal stall" or a ground effect problem? I
think that if this has happened it was due to normal stalling of the wing
and the pilot should expect this and work to prevent it by watching
airspeed and AOA.
>B) The nuisance of not being able to hold the nose off after controlled
>main
>landing gear touchdown,
>
I am not so sure this is just a nuisance. When a nose gear breaks due to
repeated slamming it could get very expensive.
Mark
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lgdavid(at)roadrunner.com
Guest
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| Posted: Fri Apr 08, 2011 10:00 am Post subject: Landing the KIS TR-1 |
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Hi Mark,et al,
I recall in the early days of this list there were a number of bent nose
gears, broken props, and a picture of one nose over in a muddy field.
Maybe Rich can recall more specifics. I recall there was a quasi AD to
strengthen the nose gear. Over the years there were a number of patches
to resolve this common problem (or problems) that the current
discussions suggest is design related. I wish Vance Jaqua were still
with us. He would love this discussion. I almost wish I had a project
to try out these fresh ideas. Larry
On 4/8/2011 8:31 AM, Mark Kettering wrote:
| Quote: |
> However I would like to clarify and emphasize that:
>
> A) The danger / discomfort of having the nose abruptly drop while still
> airborne and close to the landing surface, and
Has this ever happened to anyone? If so was it caused by stalling the wing? If so was this due to "normal stall" or a ground effect problem? I think that if this has happened it was due to normal stalling of the wing and the pilot should expect this and work to prevent it by watching airspeed and AOA.
> B) The nuisance of not being able to hold the nose off after controlled main
> landing gear touchdown,
>
I am not so sure this is just a nuisance. When a nose gear breaks due to repeated slamming it could get very expensive.
Mark
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BlueSkyFlier
Joined: 27 Jan 2011
Posts: 74
Location: UK
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| Posted: Fri Apr 08, 2011 1:16 pm Post subject: Re: Landing the KIS TR-1 |
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I think it would be quite unfair to characterize the behaviours we are discussing here as a design problem/deficiency.
Instead, it should simply be recognized that a laminar flow wing has peculiar drag characteristics which change abruptly when angle of attack gets outside of a specific range. With full flaps in ground effect that angle may well be significantly smaller than one would otherwise expect. (Mark and I independently arrived at a maximum attitude of about 5 to 6 degrees during landing)
There are no free lunches. The price to be paid for the excellent high speed performance of the TR-1 is that a conservative angle of attack is advisable during landing to avoid all the potential pitfalls resulting from the speed-optimised configuration.
The main gear location could perhaps have been better, but it hasn't caused me any problems, provided that the wheels touch down gently enough.
Like any other vehicle this one has its particular idiosynchrasies. Now that we have a fairly good idea what they are, all we need to do is to respect them.
Happy landings,
Alfred.
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ftyoder(at)yoderbuilt.com
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| Posted: Fri Apr 08, 2011 7:16 pm Post subject: Landing the KIS TR-1 |
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All Ya All,(Texas speak)
I land my TR-1 with full flaps and 1100 to 1300 RPM. Touch down is about 75 MPH and I can always hold the nose gear off, if my timing is good. If I am tardy, the nose gear will hit but not hard. I have the elevator extension also. Sometimes my AOA is high enough that I loose the runway in the flair and have to look out the door window, the nose gear is still easy to hold off at main gear touchdown.
[quote] ---
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