Today's Message Index:
----------------------
1. 03:59 AM - long legs (Patrick Ladd)
2. 04:25 AM - Re: long legs (Richard Pike)
3. 06:34 AM - Re: long legs (Charlie England)
4. 06:46 AM - Re: long legs (Dennis Rowe)
5. 07:40 AM - Re: long legs (Patrick Ladd)
6. 08:28 AM - Re: long legs (Charlie England)
7. 10:18 AM - Re: Re: long legs (Patrick Ladd)
Message 1
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I may be sticking my neck out here and asking get slapped down but will
someone explain why having longer legs increases the STOL capability of
our a/c. Excepting of course the case where you deliberately hold the
tail down on take off.
I agree with all the advantages which John listed, more wing area
exposed thus slowing landing run etc. However the first thing which
most of us do on take off is to get the tail up into flying position
thus reducing drag and allowing increased acceleration. When the tail is
up the the length of the u/c is irrelevant. In fact having the extra
wing area exposed by having long legs slows the planes acceleration for
exactly the same reason that it shortens the landing run.
When the plane is up on two wheels the AOA is that which was designed
in.
Comments about commercial a/c are largely irrelevant as they are
(mainly) tricycle gear and the wing is in flying position (more or less)
the whole time.
There may be good reasons for making u/c legs longer but I am not
convinced that STOL is one of them except the `keep the skid on the
ground until she drags herself off` scenario which I mentioned..
Enlightenment please.
Pat
Message 2
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Make the gear legs long enough and your fat friends will not be able to get in.
Which enables the airplane to get off the ground quicker.
Glad to help out.
--------
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0
Would you consider yourself to be a good person?
https://www.youtube.com/watch?v=VWcDXT6pH7A
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=453919#453919
Message 3
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On Sat, Mar 19, 2016 at 5:58 AM, Patrick Ladd <patrickjladd@hotmail.com>
wrote:
> I may be sticking my neck out here and asking get slapped down but will
> someone explain why having longer legs increases the STOL capability of our
> a/c. Excepting of course the case where you deliberately hold the tail down
> on take off.
> I agree with all the advantages which John listed, more wing area exposed
> thus slowing landing run etc. However the first thing which most of us do
> on take off is to get the tail up into flying position thus reducing drag
> and allowing increased acceleration. When the tail is up the the length of
> the u/c is irrelevant. In fact having the extra wing area exposed by having
> long legs slows the planes acceleration for exactly the same reason that it
> shortens the landing run.
> When the plane is up on two wheels the AOA is that which was designed in.
> Comments about commercial a/c are largely irrelevant as they are (mainly)
> tricycle gear and the wing is in flying position (more or less) the whole
> time.
> There may be good reasons for making u/c legs longer but I am not
> convinced that STOL is one of them except the `keep the skid on the ground
> until she drags herself off` scenario which I mentioned..
> Enlightenment please.
> Pat
>
I'll take a crack at it, in general terms. You can decide if it applies to
Kolbs.
If you watch videos of hard core bush flying, the pilot will hold the
brakes and raise the tail prior to starting the takeoff roll (to minimize
wing drag, as you point out). When he's got max available power, he
releases the brakes. As soon as he's got minimum flying speed, he rotates &
the plane jumps into the air. Now, most taildraggers sit on the ground with
the wing at a significantly lower angle than critical (stall) AOA. So in
stock condition, they can't be rotated to lift off at anywhere near stall
speed. So, their minimum speed for takeoff is limited (made higher) by the
length of the main gear legs. If the same trick is tried with 'short legs',
the pilot would slam the tailwheel into the ground when he rotates. FWIW,
there are videos of airliners actually dragging the rear of the fuselage on
the ground when they over-rotate. Airliners (at least some of them)
actually give up significant landing speed reduction because they don't
want the weight of long gear legs when they always have plenty of runway
for 'driving it on' in landing.
In landing mode, it's just as important. In normal flying, a pilot would
try to '3 point', having the mains & tailwheel touch at the same time to
land at minimum airspeed. But, since the wing isn't at critical AOA in 3
point attitude, he's not really landing at minimum airspeed. If the mains
were longer, he could land slower. In bush flying, it gets worse. Again,
watching extreme bush flying, you'll see the pilot wheel land and keep the
tail off the ground until he's almost stopped. With a typical taildragger,
he's carrying quite a bit of extra airspeed to 'wheel land' the plane, but
he does it to protect the tailwheel from damage, from rough ground and from
impact damage of dropping it in. If the legs are extended enough, he can
have full stall AOA available from the wing, without the tailwheel being on
the ground. Obviously, this will let him land slower & shorter.
Does any of that apply to Kolbs?
Message 4
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Bingo on all points.
Do not archive
Dennis "Skid" Rowe
> On Mar 19, 2016, at 9:34 AM, Charlie England <ceengland7@gmail.com> wrote:
>
>
>
>> On Sat, Mar 19, 2016 at 5:58 AM, Patrick Ladd <patrickjladd@hotmail.com> w
rote:
>> I may be sticking my neck out here and asking get slapped down but will s
omeone explain why having longer legs increases the STOL capability of our a
/c. Excepting of course the case where you deliberately hold the tail down o
n take off.
>> I agree with all the advantages which John listed, more wing area exposed
thus slowing landing run etc. However the first thing which most of us do o
n take off is to get the tail up into flying position thus reducing drag and
allowing increased acceleration. When the tail is up the the length of the u
/c is irrelevant. In fact having the extra wing area exposed by having long l
egs slows the planes acceleration for exactly the same reason that it short
ens the landing run.
>> When the plane is up on two wheels the AOA is that which was designed in.
>> Comments about commercial a/c are largely irrelevant as they are (mainly)
tricycle gear and the wing is in flying position (more or less) the whole t
ime.
>> There may be good reasons for making u/c legs longer but I am not convinc
ed that STOL is one of them except the `keep the skid on the ground until s
he drags herself off` scenario which I mentioned..
>> Enlightenment please.
>> Pat
>
> I'll take a crack at it, in general terms. You can decide if it applies to
Kolbs.
>
> If you watch videos of hard core bush flying, the pilot will hold the brak
es and raise the tail prior to starting the takeoff roll (to minimize wing d
rag, as you point out). When he's got max available power, he releases the b
rakes. As soon as he's got minimum flying speed, he rotates & the plane jump
s into the air. Now, most taildraggers sit on the ground with the wing at a s
ignificantly lower angle than critical (stall) AOA. So in stock condition, t
hey can't be rotated to lift off at anywhere near stall speed. So, their min
imum speed for takeoff is limited (made higher) by the length of the main ge
ar legs. If the same trick is tried with 'short legs', the pilot would slam t
he tailwheel into the ground when he rotates. FWIW, there are videos of airl
iners actually dragging the rear of the fuselage on the ground when they ove
r-rotate. Airliners (at least some of them) actually give up significant lan
ding speed reduction because they don't want the weight of long gear legs wh
en they always have plenty of runway for 'driving it on' in landing.
>
> In landing mode, it's just as important. In normal flying, a pilot would t
ry to '3 point', having the mains & tailwheel touch at the same time to land
at minimum airspeed. But, since the wing isn't at critical AOA in 3 point a
ttitude, he's not really landing at minimum airspeed. If the mains were long
er, he could land slower. In bush flying, it gets worse. Again, watching ext
reme bush flying, you'll see the pilot wheel land and keep the tail off the g
round until he's almost stopped. With a typical taildragger, he's carrying q
uite a bit of extra airspeed to 'wheel land' the plane, but he does it to pr
otect the tailwheel from damage, from rough ground and from impact damage of
dropping it in. If the legs are extended enough, he can have full stall AOA
available from the wing, without the tailwheel being on the ground. Obvious
ly, this will let him land slower & shorter.
>
> Does any of that apply to Kolbs?
Message 5
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Thanks Charlie,
i can see the reasoning and in fact I saw a guy up in Fairbanks in a
Super Cub pulling the `tail up, full throttle trick`. He powered up,
standing on the brakes, hauled it off the ground by pushing the tail
down and climbing out at just above stall speed.. He did a circuit and
landed again, tail down and hanging on his prop at full chat, like a
helicopter. All in an incredibly short time. I filmed it with a video
camera in one take.
I somehow doubt that many Kolbers have the brakes, to be able to come
close to emulating that performance. Without some actual measurements it
is impossible to calculate accurately the increased AOA available and I
was never any good at trig anyway but assuming 10ft between mains and
tail wheel and an increase in height of the gear legs of say 4 inches,
by how many degrees does that increase the AOA? 1 degree? 1.5 degrees.?
No doubt someone on the list will work it out.
It may well be worth extending legs for other reasons but STOL?.
Questionable.
Pat
From: Charlie England
Sent: Saturday, March 19, 2016 1:34 PM
Subject: Re: Kolb-List: long legs
On Sat, Mar 19, 2016 at 5:58 AM, Patrick Ladd <patrickjladd@hotmail.com>
wrote:
I may be sticking my neck out here and asking get slapped down but
will someone explain why having longer legs increases the STOL
capability of our a/c. Excepting of course the case where you
deliberately hold the tail down on take off.
I agree with all the advantages which John listed, more wing area
exposed thus slowing landing run etc. However the first thing which
most of us do on take off is to get the tail up into flying position
thus reducing drag and allowing increased acceleration. When the tail is
up the the length of the u/c is irrelevant. In fact having the extra
wing area exposed by having long legs slows the planes acceleration for
exactly the same reason that it shortens the landing run.
When the plane is up on two wheels the AOA is that which was designed
in.
Comments about commercial a/c are largely irrelevant as they are
(mainly) tricycle gear and the wing is in flying position (more or less)
the whole time.
There may be good reasons for making u/c legs longer but I am not
convinced that STOL is one of them except the `keep the skid on the
ground until she drags herself off` scenario which I mentioned..
Enlightenment please.
Pat
I'll take a crack at it, in general terms. You can decide if it applies
to Kolbs.
If you watch videos of hard core bush flying, the pilot will hold the
brakes and raise the tail prior to starting the takeoff roll (to
minimize wing drag, as you point out). When he's got max available
power, he releases the brakes. As soon as he's got minimum flying speed,
he rotates & the plane jumps into the air. Now, most taildraggers sit on
the ground with the wing at a significantly lower angle than critical
(stall) AOA. So in stock condition, they can't be rotated to lift off at
anywhere near stall speed. So, their minimum speed for takeoff is
limited (made higher) by the length of the main gear legs. If the same
trick is tried with 'short legs', the pilot would slam the tailwheel
into the ground when he rotates. FWIW, there are videos of airliners
actually dragging the rear of the fuselage on the ground when they
over-rotate. Airliners (at least some of them) actually give up
significant landing speed reduction because they don't want the weight
of long gear legs when they always have plenty of runway for 'driving it
on' in landing.
In landing mode, it's just as important. In normal flying, a pilot would
try to '3 point', having the mains & tailwheel touch at the same time to
land at minimum airspeed. But, since the wing isn't at critical AOA in 3
point attitude, he's not really landing at minimum airspeed. If the
mains were longer, he could land slower. In bush flying, it gets worse.
Again, watching extreme bush flying, you'll see the pilot wheel land and
keep the tail off the ground until he's almost stopped. With a typical
taildragger, he's carrying quite a bit of extra airspeed to 'wheel land'
the plane, but he does it to protect the tailwheel from damage, from
rough ground and from impact damage of dropping it in. If the legs are
extended enough, he can have full stall AOA available from the wing,
without the tailwheel being on the ground. Obviously, this will let him
land slower & shorter.
Does any of that apply to Kolbs?
Message 6
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Since typical AOA is around 14-15 degrees at stall, a 1.5 degree increase
could be close to a 10% increase in 3 point attitude. Not something to
sneeze at.
Again, you must decide if it applies to Kolbs, and whether it actually
matters to you for your style of flying. Who would think that a stock Super
Cub needed shorter field performance, but a lot of bush fliers obviously
consider it inadequate for their purposes.
On Sat, Mar 19, 2016 at 9:40 AM, Patrick Ladd <patrickjladd@hotmail.com>
wrote:
> Thanks Charlie,
> i can see the reasoning and in fact I saw a guy up in Fairbanks in a Super
> Cub pulling the `tail up, full throttle trick`. He powered up, standing on
> the brakes, hauled it off the ground by pushing the tail down and climbing
> out at just above stall speed.. He did a circuit and landed again, tail
> down and hanging on his prop at full chat, like a helicopter. All in an
> incredibly short time. I filmed it with a video camera in one take.
> I somehow doubt that many Kolbers have the brakes, to be able to come
> close to emulating that performance. Without some actual measurements it is
> impossible to calculate accurately the increased AOA available and I was
> never any good at trig anyway but assuming 10ft between mains and tail
> wheel and an increase in height of the gear legs of say 4 inches, by how
> many degrees does that increase the AOA? 1 degree? 1.5 degrees.? No doubt
> someone on the list will work it out.
> It may well be worth extending legs for other reasons but STOL?.
> Questionable.
>
> Pat
>
> *From:* Charlie England <ceengland7@gmail.com>
> *Sent:* Saturday, March 19, 2016 1:34 PM
> *To:* kolb-list@matronics.com
> *Subject:* Re: Kolb-List: long legs
>
>
> On Sat, Mar 19, 2016 at 5:58 AM, Patrick Ladd <patrickjladd@hotmail.com>
> wrote:
>
>> I may be sticking my neck out here and asking get slapped down but will
>> someone explain why having longer legs increases the STOL capability of our
>> a/c. Excepting of course the case where you deliberately hold the tail down
>> on take off.
>> I agree with all the advantages which John listed, more wing area exposed
>> thus slowing landing run etc. However the first thing which most of us do
>> on take off is to get the tail up into flying position thus reducing drag
>> and allowing increased acceleration. When the tail is up the the length of
>> the u/c is irrelevant. In fact having the extra wing area exposed by having
>> long legs slows the planes acceleration for exactly the same reason that it
>> shortens the landing run.
>> When the plane is up on two wheels the AOA is that which was designed in.
>> Comments about commercial a/c are largely irrelevant as they are (mainly)
>> tricycle gear and the wing is in flying position (more or less) the whole
>> time.
>> There may be good reasons for making u/c legs longer but I am not
>> convinced that STOL is one of them except the `keep the skid on the ground
>> until she drags herself off` scenario which I mentioned..
>> Enlightenment please.
>> Pat
>>
>
> I'll take a crack at it, in general terms. You can decide if it applies to
> Kolbs.
>
> If you watch videos of hard core bush flying, the pilot will hold the
> brakes and raise the tail prior to starting the takeoff roll (to minimize
> wing drag, as you point out). When he's got max available power, he
> releases the brakes. As soon as he's got minimum flying speed, he rotates &
> the plane jumps into the air. Now, most taildraggers sit on the ground with
> the wing at a significantly lower angle than critical (stall) AOA. So in
> stock condition, they can't be rotated to lift off at anywhere near stall
> speed. So, their minimum speed for takeoff is limited (made higher) by the
> length of the main gear legs. If the same trick is tried with 'short legs',
> the pilot would slam the tailwheel into the ground when he rotates. FWIW,
> there are videos of airliners actually dragging the rear of the fuselage on
> the ground when they over-rotate. Airliners (at least some of them)
> actually give up significant landing speed reduction because they don't
> want the weight of long gear legs when they always have plenty of runway
> for 'driving it on' in landing.
>
> In landing mode, it's just as important. In normal flying, a pilot would
> try to '3 point', having the mains & tailwheel touch at the same time to
> land at minimum airspeed. But, since the wing isn't at critical AOA in 3
> point attitude, he's not really landing at minimum airspeed. If the mains
> were longer, he could land slower. In bush flying, it gets worse. Again,
> watching extreme bush flying, you'll see the pilot wheel land and keep the
> tail off the ground until he's almost stopped. With a typical taildragger,
> he's carrying quite a bit of extra airspeed to 'wheel land' the plane, but
> he does it to protect the tailwheel from damage, from rough ground and from
> impact damage of dropping it in. If the legs are extended enough, he can
> have full stall AOA available from the wing, without the tailwheel being on
> the ground. Obviously, this will let him land slower & shorter.
>
> Does any of that apply to Kolbs?
>
Message 7
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Good point Richard.
In general my fat friends did not get a look in. Fat girls now.....Pat
-----Original Message-----
From: Richard Pike
Sent: Saturday, March 19, 2016 11:24 AM
Subject: Kolb-List: Re: long legs
Make the gear legs long enough and your fat friends will not be able to get
in. Which enables the airplane to get off the ground quicker.
Glad to help out.
--------
Richard Pike
Kolb MKIII N420P (420ldPoops)
Kingsport, TN 3TN0
Would you consider yourself to be a good person?
https://www.youtube.com/watch?v=VWcDXT6pH7A
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=453919#453919
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