XP-39 and the Claims

[FLYBOYJ]

We're talking about stalls, not spins. To spin a plane has to stall first. Spinning was prohibited in almost every AAF fighter flight manual.

Not in that P-39 manual and again it is cautioned.

"In any condition" means clean, gear and flaps down and any combination thereof.

No, you're wrong - research stalling configurations and types, more than just putting the stick forward.

"At any time after the stall occurred" means just that.

Don't know what you're talking about on that one

Again it's quite evident you don't know different types of stalls and aircraft configurations aircraft can be stalled to.

 

[FLYBOYJ]

"Recovery could be effected promptly by applying down elevator." Straight from an official test. Hard to argue with that, but know some of you will.

You edited your post so I'll address that - yes, elevator straight down but that's not the only thing happening

 

[tyrodtom]

Most spins occur when you stall while turning.
You tighten up the turn too much, the wing on the inside of the turn stalls first, it drops, and you've got a spin.
I've flown, I've experienced this with a instructor, it's a eye opener.

And there's several members of this forum that has 100 of times more experience than I have, I would never consider disagreeing with them on stalls and spins.
And yet you, P-39 expert, evidently seem to think you know more from a little online research.

 

[DerAdlerIstGelandet]

I love this "Not having stall warning has no bearing on the stall characteristics of an aircraft" BS. You stall an aircraft at low altitude because there was no warning, you may not recover it before making a hole in the ground. Then this whole "we are talking about stalls not spins" BS is also tiring. If you stall without warning you are more likely to spin the aircraft.

Anybody else think this thread has run its course, serves no more purpose, and should go the way of the dodo bird?

 

[FLYBOYJ]

I love this "Not having stall warning has no bearing on the stall characteristics of an aircraft" BS. You stall an aircraft at low altitude because there was no warning, you may not recover it before making a hole in the ground. Then this whole "we are talking about stalls not spins" BS is also tiring. If you stall without warning you are more likely to spin the aircraft.

Anybody else think this thread has run its course, serves no more purpose, and should go the way of the dodo bird?

Yeah - it's like talking to a disconnected telephone

 

[DerAdlerIstGelandet]

Most spins occur when you stall while turning.
You tighten up the turn too much, the wing on the inside of the turn stalls first, it drops, and you've got a spin.
I've flown, I've experienced this with a instructor, it's a eye opener.

And there's several members of this forum that has 100 of times more experience than I have, I would never consider disagreeing with them on stalls and spins.
And yet you, P-39 expert, evidently seem to think you know more from a little online research.

Yeap, I mentioned it earlier in this thread, but on my first cross country solo I was flying into my second destination. Tower told me to fly right traffic to avoid some obstacle. As I was turning base to final I misjudged my turn. I turned hard right to correct the turn. I was already at slow speed, and low altitude in the pattern. The high bank angle bled off even more speed, and the stall warning went off. I eased the bank angle, and prevented the stall. Then corrected my approach and performed one of the worst landings I have ever done. The entire situation scared the living shit out of me. At the altitude I was at, there was no chance of recovery had I stalled (and probably spun because I was uncoordinated at the time). It was a very humbling learning experience to say the least.

Now imagine this happening in low altitude combat in a high performance fighter aircraft with little to no stall warning...

 

[DerAdlerIstGelandet]

I have the solution to all of these problems...

Take a P-39 and put Balkan Crosses on it, and rename it the Mustang and it will never stall, ever.

 

[buffnut453]

Yeah - it's like talking to a disconnected telephone

Sorry, were you saying something?

I couldn't resist!!

 

[XBe02Drvr]

We're talking about stalls, not spins. To spin a plane has to stall first. Spinning was prohibited in almost every AAF fighter flight manual.

This is where your understanding falls short. Stalls and spins are parts of the same elephant. In fact a spin is basically a steady state partial stall; one wing firmly stalled while the other is still flying. That's what gives it the corkscrew motion, like a descending maple seed. Spins occur when one wing stalls before the other, usually as a result of a yawing motion, or a slipping or skidding condition as the critical AoA is approached. In this case the advancing wing experiences a slight increase in airspeed and reduction in AoA, while the retreating wing loses airspeed and its AoA goes critical, stalling the airflow, losing lift, and dramatically increasing drag. Retreating wing is dragged back and down, advancing wing gains airspeed and lift, rising up and over the top, while the windshield fills up with trees that start to go round and round and get bigger quickly. So there you are in a fully developed spin without ever fully stalling your airplane.
I just described a docile spin entry entered from 1 G level flight without a whole lot of power on the plane, caused by a "sloppy" approach to a stall. An instructor gets used to seeing this, as most students haven't developed the finesse yet to exert precise rudder-aileron coordination at high AoAs. That's why we devote a lot of attention to slow flight maneuvering before we start messing with stalls.
Now reenact this scenario in a 60° banked 2 G turn with the engine at full power to maintain altitude. As you approach critical AoA, the difference in lift between your faster traveling outboard wing and your inboard wing is starting to become significant, subtly changing the balance point of rudder-aileron coordination. With 2 Gs on, the consequences of any inadvertent asymmetry will radically increase the rolling motion when one wing stalls before the other, likely resulting in a head banger.
Now put yourself in a P39, an FW190, a P40, or fighter of your choice, pulling 4 Gs with tracers zinging under your tailfeathers from a bad guy "saddled up" in your six. Wouldn't it be nice to have a buffet or a burble, or even a stall horn to let you know that if you pull just a little harder, you're going to snap roll into his line of fire?

 

[P-39 Expert]

Not in that P-39 manual and again it is cautioned.

No, you're wrong - research stalling configurations and types, more than just putting the stick forward.

Don't know what you're talking about on that one

Again it's quite evident you don't know different types of stalls and aircraft configurations aircraft can be stalled to.

I know that "any configuration" means just that. Why are you trying to disagree with an official performance test conducted by the NACA for the AAF? It's right there in black and white. That's all new material, only posted to the wwiiaircraft site in 2012. You persist in quoting 75 year old heresay when you have the actual report right there.

And please keep telling me that I don't know what I am talking about when I'm quoting verbatim an official report. And please tell the posters on here to keep insulting me with comments like "SMH", like I don't know what that means. Can we have a grownup discussion here? That means people expressing differing views in a civilized manner.

 

[tyrodtom]

I know that "any configuration" means just that. Why are you trying to disagree with an official performance test conducted by the NACA for the AAF? It's right there in black and white. That's all new material, only posted to the wwiiaircraft site in 2012. You persist in quoting 75 year old heresay when you have the actual report right there.

And please keep telling me that I don't know what I am talking about when I'm quoting verbatim an official report. And please tell the posters on here to keep insulting me with comments like "SMH", like I don't know what that means. Can we have a grownup discussion here? That means people expressing differing views in a civilized manner.

You're quoting a report meant to be read by pilots, it presupposes more than a little knowledge of aviation.

 

[pbehn]

United States World War II Aircraft Loss Statistics during Flight Training

The P-39 had 1,934 accidents in USA training, 369 were fatal involving 395 deaths and 865 planes destroyed an accident rate of 245 per 100,000, this by far the worst of any S/E type used apart from the A-36 which was a dive bomber.

 

[P-39 Expert]

This is where your understanding falls short. Stalls and spins are parts of the same elephant. In fact a spin is basically a steady state partial stall; one wing firmly stalled while the other is still flying. That's what gives it the corkscrew motion, like a descending maple seed. Spins occur when one wing stalls before the other, usually as a result of a yawing motion, or a slipping or skidding condition as the critical AoA is approached. In this case the advancing wing experiences a slight increase in airspeed and reduction in AoA, while the retreating wing loses airspeed and its AoA goes critical, stalling the airflow, losing lift, and dramatically increasing drag. Retreating wing is dragged back and down, advancing wing gains airspeed and lift, rising up and over the top, while the windshield fills up with trees that start to go round and round and get bigger quickly. So there you are in a fully developed spin without ever fully stalling your airplane.
I just described a docile spin entry entered from 1 G level flight without a whole lot of power on the plane, caused by a "sloppy" approach to a stall. An instructor gets used to seeing this, as most students haven't developed the finesse yet to exert precise rudder-aileron coordination at high AoAs. That's why we devote a lot of attention to slow flight maneuvering before we start messing with stalls.
Now reenact this scenario in a 60° banked 2 G turn with the engine at full power to maintain altitude. As you approach critical AoA, the difference in lift between your faster traveling outboard wing and your inboard wing is starting to become significant, subtly changing the balance point of rudder-aileron coordination. With 2 Gs on, the consequences of any inadvertent asymmetry will radically increase the rolling motion when one wing stalls before the other, likely resulting in a head banger.
Now put yourself in a P39, an FW190, a P40, or fighter of your choice, pulling 4 Gs with tracers zinging under your tailfeathers from a bad guy "saddled up" in your six. Wouldn't it be nice to have a buffet or a burble, or even a stall horn to let you know that if you pull just a little harder, you're going to snap roll into his line of fire?

Yet again, you're going an awfully long way here and you are not proving anything, except to tell me that I don't understand something. Please keep insulting me, it's always appreciated. Your example is applicable to any WWII fighter plane, including those with abysmal stalling characteristics.

 

[DerAdlerIstGelandet]

I know that "any configuration" means just that. Why are you trying to disagree with an official performance test conducted by the NACA for the AAF? It's right there in black and white. That's all new material, only posted to the wwiiaircraft site in 2012. You persist in quoting 75 year old heresay when you have the actual report right there.

And please keep telling me that I don't know what I am talking about when I'm quoting verbatim an official report. And please tell the posters on here to keep insulting me with comments like "SMH", like I don't know what that means. Can we have a grownup discussion here? That means people expressing differing views in a civilized manner.

I never doubted that you know what SMH means (its the one thing I don't doubt). I am SMH because of your posts. If someone shaking their head insults you, thats your problem and maybe you should figure out why.

 

[DerAdlerIstGelandet]

Yet again, you're going an awfully long way here and you are not proving anything, except to tell me that I don't understand something. Please keep insulting me, it's always appreciated. Your example is applicable to any WWII fighter plane, including those with abysmal stalling characteristics.

Like the P-39?

 

[FLYBOYJ]

I know that "any configuration" means just that. Why are you trying to disagree with an official performance test conducted by the NACA for the AAF? It's right there in black and white. That's all new material, only posted to the wwiiaircraft site in 2012. You persist in quoting 75 year old heresay when you have the actual report right there.

Because it's not as simple as what you're trying to make it. You don't even understand that there are different types of stalls and configurations and that manual is not addressing those configurations and you continue to NOT under stand the bigger picture either by ignorance or stubbornness - typical armchair response.

And please keep telling me that I don't know what I am talking about when I'm quoting verbatim an official report. And please tell the posters on here to keep insulting me with comments like "SMH", like I don't know what that means. Can we have a grownup discussion here? That means people expressing differing views in a civilized manner.

We are/ were having a grown up discussion but its YOU who continually tries to second guess some of us who have flown and worked on aircraft, some of these folks are former military pilots and ATPs who have hundreds if not thousands of hours flying. Your "hands on" aviation experience??????

No - you're creating your own firestorm by some of your own assumptions and refusing to listen to real world experience. If this is too overwhelming for you I can suggest one thing....

 

[P-39 Expert]

United States World War II Aircraft Loss Statistics during Flight Training

The P-39 had 1,934 accidents in USA training, 369 were fatal involving 395 deaths and 865 planes destroyed an accident rate of 245 per 100,000, this by far the worst of any S/E type used apart from the A-36 which was a dive bomber.

The primary role of the P-39 in the AAF from 1943 forward was advanced combat training. One would expect more accidents from pilot trainees than graduate combat pilots who had moved on to P-38s, P-47s and P-51s. Also consider the average length of each mission by type. Those P-39s held 120 gallons internal, some only 88 gallons. If they average 108 gallons each and burn 100gallons/hour then they are making 92,600 takeoffs/landings per 100000hours. A P-38 or P-40 held 150gal per engine, meaning 1.5hrs per flight or 66,670 takeoffs/landings per 100000hrs. A P-51 held 265gal or 2.65hrs per flight or 37,750 takeoffs/landings. P-47s held 305gal and burned an average of, say 150gph or 2 hours per flight. They averaged 50000 takeoffs/landings per 100000hrs. A P-39 would then make 1.4 times as many takeoffs/landings than a P-38 or P-40, 2.5 times as many as a P-51 and 1.9 times as many as a P-47. A P-38 would have 195 accidents per takeoff/landing, a P-40 would have 263 accidents per TO/L, a P-51 would have 262 per TO/L and the P-47 would have 241 accidents per TO/L. All pretty close to the P-39 with 245. All about the same, really. And the P-39 was being flown by trainees while the other models were being flown by graduate pilots. Just another way to look at it.

 

[nuuumannn]

This is turning into the Lancaster as an Atom Bomber thread. Pretty soon they'll be hanging a Fat Man under a P-39, claiming it has no detrimental impact on its aerodynamics because a turret's been removed and flying it from Okinawa to successfully bomb Nagasaki... Anything I missed?

 

[pbehn]

The primary role of the P-39 in the AAF from 1943 forward was advanced combat training. One would expect more accidents from pilot trainees than graduate combat pilots who had moved on to P-38s, P-47s and P-51s. Also consider the average length of each mission by type. Those P-39s held 120 gallons internal, some only 88 gallons. If they average 108 gallons each and burn 100gallons/hour then they are making 92,600 takeoffs/landings per 100000hours. A P-38 or P-40 held 150gal per engine, meaning 1.5hrs per flight or 66,670 takeoffs/landings per 100000hrs. A P-51 held 265gal or 2.65hrs per flight or 37,750 takeoffs/landings. P-47s held 305gal and burned an average of, say 150gph or 2 hours per flight. They averaged 50000 takeoffs/landings per 100000hrs. A P-39 would then make 1.4 times as many takeoffs/landings than a P-38 or P-40, 2.5 times as many as a P-51 and 1.9 times as many as a P-47. A P-38 would have 195 accidents per takeoff/landing, a P-40 would have 263 accidents per TO/L, a P-51 would have 262 per TO/L and the P-47 would have 241 accidents per TO/L. All pretty close to the P-39 with 245. All about the same, really. And the P-39 was being flown by trainees while the other models were being flown by graduate pilots. Just another way to look at it.

If taking off and landing is an issue with your tricycle undercart advanced trainer you need to take a look at your basic training aircraft and methods. What on earth makes you think all training missions used full tanks and ran them to empty?

 

[fubar57]

Interesting quote from Zenos, "The 39 was widely used as a trainer in the US and had a reputation for weeding out poor pilots -- permanently."