Scary story about landing on a Lake Tahoe golf course

On Sat, 01 Aug 2020 08:29:13 -0700, jfitch wrote:

This is slightly off topic, as its about an engine failure in a P-51, but
is well worth watching because the majority of it is concerned with the
pilot talking us through a video shot from the aircraft followed by a
very interesting discussion as he and the interviewer unpick his thought
processes. Here's the link:

https://youtu.be/BBpqvPujZgM

FWIW the URL was posted in a club heads-up about power loss in a tug or
TMG.



--
Martin | martin at
Gregorie | gregorie dot org

Great video, there are couple of questions I would ask though.

1) Why did he not turn much tighter to return to the airfield, one looses much less height in a tight turn that a shallow one? From a tight turn he might have been able to land downwind. Of course I do not know what the winds were, or how feasible is to land P-51 downwind.

2) Why did he cross the highway, surely he could have turned base halfway down the strip and have enough runway to stop.

Whilst I appreciate that he did not do it under the pressure of the situation, I was surprised however, that it did not come up in the discussion.

Cheers

Paul

On Sunday, 2 August 2020 03:05:48 UTC+10, Martin Gregorie wrote:
On Sat, 01 Aug 2020 08:29:13 -0700, jfitch wrote:

This is slightly off topic, as its about an engine failure in a P-51, but
is well worth watching because the majority of it is concerned with the
pilot talking us through a video shot from the aircraft followed by a
very interesting discussion as he and the interviewer unpick his thought
processes. Here's the link:

https://youtu.be/BBpqvPujZgM

FWIW the URL was posted in a club heads-up about power loss in a tug or
TMG.



--
Martin | martin at
Gregorie | gregorie dot org

On Sun, 02 Aug 2020 03:39:34 -0700, Paul B wrote:

Great video, there are couple of questions I would ask though.

1) Why did he not turn much tighter to return to the airfield, one
looses much less height in a tight turn that a shallow one? From a tight
turn he might have been able to land downwind. Of course I do not know
what the winds were, or how feasible is to land P-51 downwind.

2) Why did he cross the highway, surely he could have turned base
halfway down the strip and have enough runway to stop.

If you have Google Earth or similar, go he
52° 5'32.77"N 0° 7'43.46"E

Take a look at the situation. From the video it looks as though he was
flying a left-hand circuit, with the downwind leg on the north of the
airfield. This means that there was an easterly, so they would have
crossed the motorway immediately after takeoff. The main runway was
shortened when the M11 motorway was built across it in 1977, 1200ft from
its eastern end.

Here I'm guessing but its likely the formation formed up ENE from the
airfield, maybe somewhere south of Whittlesford or Pampisford, ready for
a pass down runway 24.

Turning in early wouldn't have been a good idea with lots of buildings to
cross: you can see them off to his left in the video and doing so would
also have meant flying over a lot of spectators, so definitely a no-no.

Whilst I appreciate that he did not do it under the pressure of the
situation, I was surprised however, that it did not come up in the
discussion.

I thought the pilot said he considered and discarded that option. Reason
left unsaid, but buildings and lots of people would have been a good
enough reason for that.

This is slightly off topic, as its about an engine failure in a P-51,
but is well worth watching because the majority of it is concerned with
the pilot talking us through a video shot from the aircraft followed by
a very interesting discussion as he and the interviewer unpick his
thought processes. Here's the link:

https://youtu.be/BBpqvPujZgM



--
Martin | martin at
Gregorie | gregorie dot org

I recall hearing the pilot say that he had his gear up to extend his
glide and someone yelled on the radio about that.Â* In the heat of the
moment the radio call made him turn away from the airport.

On 8/2/2020 5:41 AM, Martin Gregorie wrote:
On Sun, 02 Aug 2020 03:39:34 -0700, Paul B wrote:

Great video, there are couple of questions I would ask though.

1) Why did he not turn much tighter to return to the airfield, one
looses much less height in a tight turn that a shallow one? From a tight
turn he might have been able to land downwind. Of course I do not know
what the winds were, or how feasible is to land P-51 downwind.

2) Why did he cross the highway, surely he could have turned base
halfway down the strip and have enough runway to stop.

If you have Google Earth or similar, go he
52° 5'32.77"N 0° 7'43.46"E

Take a look at the situation. From the video it looks as though he was
flying a left-hand circuit, with the downwind leg on the north of the
airfield. This means that there was an easterly, so they would have
crossed the motorway immediately after takeoff. The main runway was
shortened when the M11 motorway was built across it in 1977, 1200ft from
its eastern end.

Here I'm guessing but its likely the formation formed up ENE from the
airfield, maybe somewhere south of Whittlesford or Pampisford, ready for
a pass down runway 24.

Turning in early wouldn't have been a good idea with lots of buildings to
cross: you can see them off to his left in the video and doing so would
also have meant flying over a lot of spectators, so definitely a no-no.

Whilst I appreciate that he did not do it under the pressure of the
situation, I was surprised however, that it did not come up in the
discussion.

I thought the pilot said he considered and discarded that option. Reason
left unsaid, but buildings and lots of people would have been a good
enough reason for that.

This is slightly off topic, as its about an engine failure in a P-51,
but is well worth watching because the majority of it is concerned with
the pilot talking us through a video shot from the aircraft followed by
a very interesting discussion as he and the interviewer unpick his
thought processes. Here's the link:

https://youtu.be/BBpqvPujZgM



--
Dan, 5J

He mentioned multiple times that he was low energy - low altitude, low airspeed. In another portion of the interview he mentioned the machine guns were whistling, which is a well known indicator that your angle of attack is critical. Turning tighter would increase wing load, which increases stall speed, which increases the chance of a low speed stall/spin. My guess is that was a top concern at the time.

On Sunday, August 2, 2020 at 5:39:36 AM UTC-5, Paul B wrote:
Great video, there are couple of questions I would ask though.

1) Why did he not turn much tighter to return to the airfield, one looses much less height in a tight turn that a shallow one? From a tight turn he might have been able to land downwind. Of course I do not know what the winds were, or how feasible is to land P-51 downwind.

2) Why did he cross the highway, surely he could have turned base halfway down the strip and have enough runway to stop.

Whilst I appreciate that he did not do it under the pressure of the situation, I was surprised however, that it did not come up in the discussion.

Cheers

Paul

On Sunday, 2 August 2020 03:05:48 UTC+10, Martin Gregorie wrote:
On Sat, 01 Aug 2020 08:29:13 -0700, jfitch wrote:

This is slightly off topic, as its about an engine failure in a P-51, but
is well worth watching because the majority of it is concerned with the
pilot talking us through a video shot from the aircraft followed by a
very interesting discussion as he and the interviewer unpick his thought
processes. Here's the link:

https://youtu.be/BBpqvPujZgM

FWIW the URL was posted in a club heads-up about power loss in a tug or
TMG.



--
Martin | martin at
Gregorie | gregorie dot org

He could safely turn tighter by letting the speed increase as he banked more; put
another way, maintain his angle of attack (NOT the airspeed) as he increases the bank.

wrote on 8/2/2020 8:34 AM:
He mentioned multiple times that he was low energy - low altitude, low airspeed. In another portion of the interview he mentioned the machine guns were whistling, which is a well known indicator that your angle of attack is critical. Turning tighter would increase wing load, which increases stall speed, which increases the chance of a low speed stall/spin. My guess is that was a top concern at the time.

On Sunday, August 2, 2020 at 5:39:36 AM UTC-5, Paul B wrote:
Great video, there are couple of questions I would ask though.

1) Why did he not turn much tighter to return to the airfield, one looses much less height in a tight turn that a shallow one? From a tight turn he might have been able to land downwind. Of course I do not know what the winds were, or how feasible is to land P-51 downwind.

2) Why did he cross the highway, surely he could have turned base halfway down the strip and have enough runway to stop.

Whilst I appreciate that he did not do it under the pressure of the situation, I was surprised however, that it did not come up in the discussion.

Cheers

Paul

On Sunday, 2 August 2020 03:05:48 UTC+10, Martin Gregorie wrote:
On Sat, 01 Aug 2020 08:29:13 -0700, jfitch wrote:

This is slightly off topic, as its about an engine failure in a P-51, but
is well worth watching because the majority of it is concerned with the
pilot talking us through a video shot from the aircraft followed by a
very interesting discussion as he and the interviewer unpick his thought
processes. Here's the link:

https://youtu.be/BBpqvPujZgM

FWIW the URL was posted in a club heads-up about power loss in a tug or
TMG.



--
Martin | martin at
Gregorie | gregorie dot org



--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

I must be missing something. He has no excess altitude to convert to speed.. He has no engine to add thrust. So, exactly how is he supposed to increase speed?

On Sunday, August 2, 2020 at 11:46:24 AM UTC-5, Eric Greenwell wrote:
He could safely turn tighter by letting the speed increase as he banked more; put
another way, maintain his angle of attack (NOT the airspeed) as he increases the bank.

res wrote on 8/2/2020 8:34 AM:
He mentioned multiple times that he was low energy - low altitude, low airspeed. In another portion of the interview he mentioned the machine guns were whistling, which is a well known indicator that your angle of attack is critical. Turning tighter would increase wing load, which increases stall speed, which increases the chance of a low speed stall/spin. My guess is that was a top concern at the time.

On Sunday, August 2, 2020 at 5:39:36 AM UTC-5, Paul B wrote:
Great video, there are couple of questions I would ask though.

1) Why did he not turn much tighter to return to the airfield, one looses much less height in a tight turn that a shallow one? From a tight turn he might have been able to land downwind. Of course I do not know what the winds were, or how feasible is to land P-51 downwind.

2) Why did he cross the highway, surely he could have turned base halfway down the strip and have enough runway to stop.

Whilst I appreciate that he did not do it under the pressure of the situation, I was surprised however, that it did not come up in the discussion..

Cheers

Paul

On Sunday, 2 August 2020 03:05:48 UTC+10, Martin Gregorie wrote:
On Sat, 01 Aug 2020 08:29:13 -0700, jfitch wrote:

This is slightly off topic, as its about an engine failure in a P-51, but
is well worth watching because the majority of it is concerned with the
pilot talking us through a video shot from the aircraft followed by a
very interesting discussion as he and the interviewer unpick his thought
processes. Here's the link:

https://youtu.be/BBpqvPujZgM

FWIW the URL was posted in a club heads-up about power loss in a tug or
TMG.



--
Martin | martin at
Gregorie | gregorie dot org



--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

The tighter turn works for gliders after a rope break, so I'm thinking (as did
Paul B), it would work for the P51 pilot.

There is an optimum bank for minimizing the loss of altitude (and he did have some
altitude). Had he turned tighter (about 40 degrees typically), he would have made
it further around the turn than making a wide turn. Yes, initially he would be a
bit lower, but his greater turn rate would more than compensates for that, and he
can get back some of the that altitude when he stops turning and slows down.


wrote on 8/2/2020 11:10 AM:
I must be missing something. He has no excess altitude to convert to speed.. He has no engine to add thrust. So, exactly how is he supposed to increase speed?

On Sunday, August 2, 2020 at 11:46:24 AM UTC-5, Eric Greenwell wrote:
He could safely turn tighter by letting the speed increase as he banked more; put
another way, maintain his angle of attack (NOT the airspeed) as he increases the bank.

res wrote on 8/2/2020 8:34 AM:
He mentioned multiple times that he was low energy - low altitude, low airspeed. In another portion of the interview he mentioned the machine guns were whistling, which is a well known indicator that your angle of attack is critical. Turning tighter would increase wing load, which increases stall speed, which increases the chance of a low speed stall/spin. My guess is that was a top concern at the time.

On Sunday, August 2, 2020 at 5:39:36 AM UTC-5, Paul B wrote:
Great video, there are couple of questions I would ask though.

1) Why did he not turn much tighter to return to the airfield, one looses much less height in a tight turn that a shallow one? From a tight turn he might have been able to land downwind. Of course I do not know what the winds were, or how feasible is to land P-51 downwind.

2) Why did he cross the highway, surely he could have turned base halfway down the strip and have enough runway to stop.

Whilst I appreciate that he did not do it under the pressure of the situation, I was surprised however, that it did not come up in the discussion..

Cheers

Paul

On Sunday, 2 August 2020 03:05:48 UTC+10, Martin Gregorie wrote:
On Sat, 01 Aug 2020 08:29:13 -0700, jfitch wrote:

This is slightly off topic, as its about an engine failure in a P-51, but
is well worth watching because the majority of it is concerned with the
pilot talking us through a video shot from the aircraft followed by a
very interesting discussion as he and the interviewer unpick his thought
processes. Here's the link:

https://youtu.be/BBpqvPujZgM

FWIW the URL was posted in a club heads-up about power loss in a tug or
TMG.



--
Martin | martin at
Gregorie | gregorie dot org



--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1



--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "A Guide to Self-Launching Sailplane Operation"
https://sites.google.com/site/motorg...ad-the-guide-1

On Sun, 2 Aug 2020 13:40:28 -0700, Eric Greenwell
wrote:

The tighter turn works for gliders after a rope break, so I'm thinking (as did
Paul B), it would work for the P51 pilot.

There is an optimum bank for minimizing the loss of altitude (and he did have some
altitude). Had he turned tighter (about 40 degrees typically), he would have made
it further around the turn than making a wide turn. Yes, initially he would be a
bit lower, but his greater turn rate would more than compensates for that, and he
can get back some of the that altitude when he stops turning and slows down.

Hi Eric,

From the video one can clearly see that his energy is barely enough to
cross the extended center line, including the flare. Definitely not
enough energy to make a turn, not to mention to drop the gear.


Let's do some maths:
When he started the turn to base leg he was between 250 and 350 ft AGL
(depending on his altimeter settings) and 150 mph.

P-51D stall speed clean: 100 mph, hence stall speed at 40 degreed
bank: 114 mph .

So, if he had flown a perfect approach at 120 MPH and 40 degrees of
bank, he would have had a turn diameter of 2305 ft, resulting in a
flight path distance of 3620 ft.

Having an altitude of 350 ft AGL, this would have needed an L/D of
10.3, with 250 ft he would have needed 14.5.

At 175 mph the L/D of the P-51D is 15:1, prop in high pitch. Close to
the stall speed L/D is an estimated 30 percent less, hence 10:1.
Propellor in low pitch will further reduce this number. I found no
numbers on the influence of open cooling flaps.
Let's assume an L/D of 10:1 for now (from the video probably a lot
lower).


Hence, the pilot might have had the chance to complete his turn if all
his factors had been in his favour, but even under these circulstances
he would not have had the energy to extend the gear. He didn't have
the altitude to extend it over the runway after the turn, and
extending it during the turn would have affected his L/D so much that
a crash was unavoidable.


If he had run out of energy (altitude and/or speed) in the last phase
of the turn, he would have definitely crashed, directly in front of
him the M-11 motorway, his flightpath still pointing at the thousands
of spectators. Hardly survivable.



Conclusion:
This landing is a perfect example of getting one's priorities right:

Fly the plane to a safe controlled landing instead of trying to get
back to the airfield, risking a probably deadly crash if only the
slightest thing goes wrong.


Cheers
Andreas

On Sun, 02 Aug 2020 08:34:47 -0700, resigler wrote:

He mentioned multiple times that he was low energy - low altitude, low
airspeed. In another portion of the interview he mentioned the machine
guns were whistling, which is a well known indicator that your angle of
attack is critical. Turning tighter would increase wing load, which
increases stall speed, which increases the chance of a low speed
stall/spin. My guess is that was a top concern at the time.

That, by itself was an interesting remark, to me anyway.

For several years I've gone to the "Little Gransden Charity Air & Car
Show", in part because its a small field, so displaying aircraft are
quite close and the tiedown area is very close. It also gets an amazing
collection of aircraft. Te Vulcan (when it was flying, BBMF aircraft and
Memphis Bell have all displayed there, along with a couple of P-51s.

Anyway, because the displays are close in, the blast of sound as a P-51
pulls G is quite obvious. I always wondered what caused it since I've not
heard any other aircraft make that noise. Now I know what it is: the gun-
barrels whistling at high AOA.

BTW, when I say Little Gransden is small, think Old Reinbeck - those
living near NYC will know what I mean. If you want to see what it's like,
here's the reference: 52° 9'58.11"N 0° 9'0.54"W The single grass strip
is 2500ft and there's usually at least one P-51 on the field during the
airshow.


--
Martin | martin at
Gregorie | gregorie dot org