About that YAK

Just got an answer on an email I sent out last night to a friend of mine who
has also watched the "Yak Near Miss" tape. We both agree the tape is real.
Both of us have flown this same maneuver in warbird demonstration flights
many times. We could be wrong of course, but our collective opinion is that
the tape is quite real.
Actually, my friend is more observant than I was in viewing the tape. He
noticed the Snowbirds parked on the line that you can see for just a nano
second as the Yak exits low. (hint...concentration on the YAK can easily
miss this :-)
I also believe I see the vertical stabilizer of one of the Blue Angels'
Hornets on that line as well.
This would indicate a rather large airshow on the North American continent
somewhere.
As an aside, if anyone is even remotely interested in the technical aspects
involved in low altitude vertical recoveries like this one when being flown
by demonstration pilots flying WW2 warbirds, I cover the subject extensively
for the P51 Mustang in a piece done by Gen Des Barker of the South African
Air Force for Aeroplane Monthly in the Feb 2004 issue; see "Precision
Decision" in that issue. Back copies can be obtained at the following
www.aeroplanemonthly.com.

Hope this helps a bit
Dudley Henriques

On 2006-12-28, Dudley Henriques wrote:
As an aside, if anyone is even remotely interested in the technical aspects
involved in low altitude vertical recoveries like this one when being flown

I'm curious to know if he actually saved it because of the extra lift
of ground effect right at the bottom, or if he really hit the ground.
Since he executed a victory roll afterwards I figured he was not worried
about the plane coming apart...

--
Ben Jackson AD7GD

http://www.ben.com/

The prop seems to be undamaged.


http://www.youtube.com:80/watch?v=C2PvcG4Vmyw

For those who did not see the link




"Ben Jackson" wrote in message
...
| On 2006-12-28, Dudley Henriques
wrote:
| As an aside, if anyone is even remotely interested in
the technical aspects
| involved in low altitude vertical recoveries like this
one when being flown
|
| I'm curious to know if he actually saved it because of the
extra lift
| of ground effect right at the bottom, or if he really hit
the ground.
| Since he executed a victory roll afterwards I figured he
was not worried
| about the plane coming apart...
|
| --
| Ben Jackson AD7GD
|
| http://www.ben.com/

I don't think he "saved it" really. He just bottomed out too low and the
mush gave him just enough room to clear.
He would have known instinctively how much back pressure he had left and
couldn't have gone past that anyway.
Once you have all the g in there that the airplane's recovery profile can
give you, you're totally committed to the recovery line that amount of g
provides. Feed in more and you're topping off the CL curve and you're done
for when that happens. If anything, he had all the stick in there the line
was giving him and just sweated out the exit .
Ground effect won't save you going through a bad recovery line. The impetus
will take you right through it into ground contact. He maxed out the line
and went tail low with just enough air under him to clear the prop tips. Had
he caught the tips with that much power on the airplane, the vibration would
have probably torn him apart through the exit.
I think I know who it was. This guy is a very good warbird pilot. He just
blew the line on this one and got away with it.
He's an even better warbird pilot now :-))
Dudley Henriques


"Ben Jackson" wrote in message
...
On 2006-12-28, Dudley Henriques wrote:
As an aside, if anyone is even remotely interested in the technical
aspects
involved in low altitude vertical recoveries like this one when being
flown

I'm curious to know if he actually saved it because of the extra lift
of ground effect right at the bottom, or if he really hit the ground.
Since he executed a victory roll afterwards I figured he was not worried
about the plane coming apart...

--
Ben Jackson AD7GD

http://www.ben.com/

Years ago Air Progress magazine had a picture of an F-15 in
Germany that did the same thing, except it was about 6
inches into the ground. The top side appeared undamaged but
there must have been a ton of dirt in the engines.



"Dudley Henriques" wrote in message
...
|I don't think he "saved it" really. He just bottomed out
too low and the
| mush gave him just enough room to clear.
| He would have known instinctively how much back pressure
he had left and
| couldn't have gone past that anyway.
| Once you have all the g in there that the airplane's
recovery profile can
| give you, you're totally committed to the recovery line
that amount of g
| provides. Feed in more and you're topping off the CL curve
and you're done
| for when that happens. If anything, he had all the stick
in there the line
| was giving him and just sweated out the exit .
| Ground effect won't save you going through a bad recovery
line. The impetus
| will take you right through it into ground contact. He
maxed out the line
| and went tail low with just enough air under him to clear
the prop tips. Had
| he caught the tips with that much power on the airplane,
the vibration would
| have probably torn him apart through the exit.
| I think I know who it was. This guy is a very good warbird
pilot. He just
| blew the line on this one and got away with it.
| He's an even better warbird pilot now :-))
| Dudley Henriques
|
|
| "Ben Jackson" wrote in message
| ...
| On 2006-12-28, Dudley Henriques
wrote:
| As an aside, if anyone is even remotely interested in
the technical
| aspects
| involved in low altitude vertical recoveries like this
one when being
| flown
|
| I'm curious to know if he actually saved it because of
the extra lift
| of ground effect right at the bottom, or if he really
hit the ground.
| Since he executed a victory roll afterwards I figured he
was not worried
| about the plane coming apart...
|
| --
| Ben Jackson AD7GD
|
| http://www.ben.com/
|
|

Some guys just live right! :-))
DH


"Jim Macklin" wrote in message
...
Years ago Air Progress magazine had a picture of an F-15 in
Germany that did the same thing, except it was about 6
inches into the ground. The top side appeared undamaged but
there must have been a ton of dirt in the engines.



"Dudley Henriques" wrote in message
...
|I don't think he "saved it" really. He just bottomed out
too low and the
| mush gave him just enough room to clear.
| He would have known instinctively how much back pressure
he had left and
| couldn't have gone past that anyway.
| Once you have all the g in there that the airplane's
recovery profile can
| give you, you're totally committed to the recovery line
that amount of g
| provides. Feed in more and you're topping off the CL curve
and you're done
| for when that happens. If anything, he had all the stick
in there the line
| was giving him and just sweated out the exit .
| Ground effect won't save you going through a bad recovery
line. The impetus
| will take you right through it into ground contact. He
maxed out the line
| and went tail low with just enough air under him to clear
the prop tips. Had
| he caught the tips with that much power on the airplane,
the vibration would
| have probably torn him apart through the exit.
| I think I know who it was. This guy is a very good warbird
pilot. He just
| blew the line on this one and got away with it.
| He's an even better warbird pilot now :-))
| Dudley Henriques
|
|
| "Ben Jackson" wrote in message
| ...
| On 2006-12-28, Dudley Henriques
wrote:
| As an aside, if anyone is even remotely interested in
the technical
| aspects
| involved in low altitude vertical recoveries like this
one when being
| flown
|
| I'm curious to know if he actually saved it because of
the extra lift
| of ground effect right at the bottom, or if he really
hit the ground.
| Since he executed a victory roll afterwards I figured he
was not worried
| about the plane coming apart...
|
| --
| Ben Jackson AD7GD
|
| http://www.ben.com/
|
|