Scary story about landing on a Lake Tahoe golf course

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

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

Yes, but only in the last 5 seconds of the flight. Right before he aborted the left hand turn, he was going to land on the strip. That was his plan.

My point is that he should have turned before he reached the freeway. Not necessarily when it was all happening, I am aware of the pressure that he was under.

However he clearly was desperate to make the runway and that mistake, to me, was a teaching moment. He did allude to the fact that a disabled aircraft is simply a tool dissipate energy, but did not discussed the fact that he was trying to reach the runway when he should not have.

Also, Martin G, from the video and the topology, his downwind was to the south of the airfield, flying West to East (approx), otherwise a left hand turn could not take him across the freeway. And as you have noted there are no obstacles or crowds on that side. So he had choices.

To reiterate, I am NOT discussing his performance during the event. I know nothing about flying P-51 etc.

I am only discussing the debrief.

Cheers

Paul







On Tuesday, 4 August 2020 10:34:35 UTC+10, Andreas Maurer wrote:
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 Mon, 03 Aug 2020 22:01:17 -0700, Paul B wrote:

Also, Martin G, from the video and the topology, his downwind was to the
south of the airfield, flying West to East (approx), otherwise a left
hand turn could not take him across the freeway. And as you have noted
there are no obstacles or crowds on that side. So he had choices.

Yes, you're right - after reviewing the start of the video a few times I
now see that I was 180 out of sync. He was turning to base when he
crossed the M.11, and then realised that he wasn't going to make the
runway, which would have required crossing the road a second time and put
it down parallel to road.


--
Martin | martin at
Gregorie | gregorie dot org

On Mon, 3 Aug 2020 22:01:17 -0700 (PDT), Paul B
wrote:

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

Yes, but only in the last 5 seconds of the flight. Right before he aborted the left hand turn, he was going to land on the strip. That was his plan.

Indeed. And instead of trying to scratch into the field, he chose the
safe option while he was still high and fast enough.


My point is that he should have turned before he reached the freeway. Not necessarily when it was all happening, I am aware of the pressure that he was under.


Even if he had started his turn earlier (in the middle of the downwind
leg) he would not have had the engery to complete it and would have
crashed into the fields south of the runway, still heading toward the
crowd - and the row of parked GA aircraft (and their personnel) in the
South of the runway.

Not to mention that the remaining runway length - if he had been able
to reach the airfield - was very close to the landing distance of a
P-51. Overshooting the runway in a tail dragger and risking a
somersault? Hmmm...


Clear case:
He made the best decision, without a doubt.

Cheers
Andreas


p.s.
And of course there are a couple of other points to consider - for
example the fact that the engine finally seized up just when he
started his turn to final. If it had delivered power for another four,
five seconds, he would have made it into the field.

"And of course there are a couple of other points to consider - for
example the fact that the engine finally seized up just when he
started his turn to final. If it had delivered power for another four,
five seconds, he would have made it into the field."

Andreas, you cannot have it both ways, if indeed the engine delivered power for extra four or five seconds AND he turned early, than he would landed without an issue. Instead his plan, up to the time when he straightened to land, was to cross a busy highway twice. Cannot see that as the best decision.

On Tuesday, August 4, 2020 at 11:47:29 PM UTC-7, Paul B wrote:
"And of course there are a couple of other points to consider - for
example the fact that the engine finally seized up just when he
started his turn to final. If it had delivered power for another four,
five seconds, he would have made it into the field."

Andreas, you cannot have it both ways, if indeed the engine delivered power for extra four or five seconds AND he turned early, than he would landed without an issue. Instead his plan, up to the time when he straightened to land, was to cross a busy highway twice. Cannot see that as the best decision.

Again, I am not questioning what he did, simply saying that he could have addressed his desire to reach the runway of a normal circuit in the briefing. I am sure that not modifying a circuit as appropriate has killed many.


Cheers

Paul




On Wednesday, 5 August 2020 at 12:51:20 am UTC+10, Andreas Maurer wrote:
On Mon, 3 Aug 2020 22:01:17 -0700 (PDT), Paul B
wrote:
"Conclusion:
This landing is a perfect example of getting one's priorities right"

Yes, but only in the last 5 seconds of the flight. Right before he aborted the left hand turn, he was going to land on the strip. That was his plan.
Indeed. And instead of trying to scratch into the field, he chose the
safe option while he was still high and fast enough.

My point is that he should have turned before he reached the freeway. Not necessarily when it was all happening, I am aware of the pressure that he was under.
Even if he had started his turn earlier (in the middle of the downwind
leg) he would not have had the engery to complete it and would have
crashed into the fields south of the runway, still heading toward the
crowd - and the row of parked GA aircraft (and their personnel) in the
South of the runway.

Not to mention that the remaining runway length - if he had been able
to reach the airfield - was very close to the landing distance of a
P-51. Overshooting the runway in a tail dragger and risking a
somersault? Hmmm...


Clear case:
He made the best decision, without a doubt.

Cheers
Andreas


p.s.
And of course there are a couple of other points to consider - for
example the fact that the engine finally seized up just when he
started his turn to final. If it had delivered power for another four,
five seconds, he would have made it into the field.

I'm still waiting for anyone to describe just when a P51 has ever been used as a towplane.

Tom

Andreas Maurer wrote on 8/3/2020 5:34 PM:
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.



Two things
- you are supposed to fly the 40 degree turn at the minimum sink speed for that
bank angle, not near stall. So, the L/D would be significantly higher than 10
- I wasn't suggesting the tighter turn would be a better choice, only that it
would get him further around. Your answer may be what Paul B is looking for, as
the person who won

--
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