Improve That Design: How Aircraft Could Have Been Made Better

[P-39 Expert]

I'm beginning to wonder if you do.
I'm pointing out that .30 caliber proof armor is minimum armor, no aircraft I'm aware of carried a smaller caliber weapon, while almost any axis aircraft you would meet ( with the exception of the Ki-43 early in the war) had additional guns that were bigger than .30 cal.
So just what good did the armor do?
What Larry Bell did IMO was create a aircraft that was so different from other aircraft it was dangerous.
Right at the end of a combat mission when the ammo is low or out, and the pilots flying skills aren't the best because he's probably dog tired.
Most aircraft handle the best at the end of the flight, if there's no battle damage, lower total weight, lower stalling speed, etc.
But in the P-39's case that's when it's most sensitive, with close to aft CG.
Pull that turn to final a little too tight, or rough, and you'll end up in a stall/spin that'll take more altitude to recover from than you've got.

Most aircraft destroyed in combat in the WW2 era would get no investigation under most conditions.
The pilot, if he survived, sometimes might have a clue. His squadron friends might see it, but are likely too busy with the mission, or their own survival , to really concentrate on exactly what happened.
And even if they could find a secure crash site, no one had the time to do a complete forensic investigation on a smoking hole in the ground, like modern crash investigations .

I feel like this is a waste of time trying to have a adult conversation with someone who evidently has no knowledge beyond what he reads, and has no real experience with anything mechanical.

The slightly aft CG after ammunition was expended did not affect approach or landing. Or any normal maneuvers for that matter, just post-stall. P-39 was as safe as any other AAF fighter.

 

[tyrodtom]

It wouldn't need to. What's going to happen when a hollow tube carrying the torque from 1150 HP in walls .020" thick at 3,000 RPM, carefully balanced and tuned to avoid resonances, is holed or furrowed by a 7.7MM round, upsetting all that balancing and tuning? I suspect the shaft would shake itself loose, possibly ripping the intermediate coupling loose from its supporting structure.

Actually, it is. Imagine you're in a dogfight, pulling 3,000 RPM and all the MP the supercharger will give you, plus fluctuating G and gyroscopic loads from your gyrations, and your reduction gearbox is disabled, suddenly unloading that engine ri

The slightly aft CG after ammunition was expended did not affect approach or landing. Or any normal maneuvers for that matter, just post-stall. P-39 was as safe as any other AAF fighter.

Sometimes landings can get a little more extreme than you seem to think, more accidents happen during landing than any other normal flight operation.
You can choose when to take off, but when landing you have to accept whatever the weather is, and your decision might be pressured by fuel shortage, then add in a tired pilot.

 

[GregP]

Regarding post 898, Graugeist, I assume you're just being sarcastic.

Other airplanes had engines mounted in engine mounts that were attached to the firewall and airframe. A few well-placed, or badly-placed depending on how you look at it, shots could essentially remove an engine mount. Especially cannon shots. The engine could depart the airframe in those cases, along with other bits and pieces that were attached to the engine somehow. We've all seen it in gun cam clips.

In the P-39, the engine was mounted to the center of the fuselage. To make the engine drop away from the airpolane, you'd have to blow the airplane in half. I'm sure that happened in combat at some point, but it didn't return from combat if it was blown in half, so there isn't a recorded driveshaft failure for it. Nobody said there wasn't driveshaft damage, what they said was therre was no recorded driveshaft failure in planes that returned from combat. There well might be and likely were driveshaft failures in airplanes that went down in combat. I'd be very surprised if there weren't, but the driveshaft was not a problem failure point for the airplane or even a blip on the chart of issues.

That doesn't magically make the P-39 a better airplane. All it means is that the driveshaft was not an issue. There were plently of other issues with the P-39, as we have expounded upon at length in the groundhog thread.

 

[XBe02Drvr]

The slightly aft CG after ammunition was expended did not affect approach or landing. Or any normal maneuvers for that matter, just post-stall. P-39 was as safe as any other AAF fighter.

BULLPUCKY! Even a docile, user friendly airplane like a Cessna 150 or Piper Warrior, or even a Beech T34 stalls more suddenly, more violently and less predictably when loaded to its aft CG limit. I used to explore this with my students, knowing that most of their future recreational and/or professional flying would be done in aft loaded planes, unlike the forward loaded scenario that prevails in training flights. We would do a careful W&B calculation, then ballast the aft baggage space to put the CG right at the aft limit at the worst case scenario for the flight, as some planes shift CG aft with fuel burn. Sometimes this would entail calculating how far forward of the aft limit we would have to set the CG to not go out of limit during the time of the lesson. A good exercise for a student who you know is going to take the family out for a ride as soon as the ink is dry on their license.
As CG approaches aft limit, stick force gradient gets lighter and lighter, and the tendency to over control increases exponentially. The last few degrees of angle of attack come much faster than expected, you get a brief "bleep" of the stall horn, and WHAM!, the nose and one wing drop sharply, your stomach tries to egress through your esophagus, and the windshield is full of trees. Not the gentle "rocking chair ride", easily controllable stall you've become accustomed to in your docile pussycat airplane. The key here is unpredictability: when it will occur, the minimal to non-existent warning, and the asymmetry of the stall break.
Now translate this to a mid-engine, high performance, high wing loading fighter plane with reduced inherent stability, a propensity for aft CG loading, and an acknowledged out-of-AAF-spec super light stick force gradient, and the assertion that approach and landing at aft CG limit (or perhaps beyond it) were "normal" is pretty hard to swallow.
Even in light, stable, easy-to-fly GA airplanes, it's not the set piece straight and level stall that will kill you; it's the descending, turning, close to the ground stall that sneaks up on you and bites you in the ass. Exponentially more so with higher performance aircraft.
And still, terrestrial aviation hasn't embraced the AoA indicator, something the sea services have been relying on for over a half century.

 

[GrauGeist]

Regarding post 898, Graugeist, I assume you're just being sarcastic

No sarcasm - I just recently watched some Luftwaffe guncam footage and in one segment, a Bf110G-2 closed in a B-24 and tore it apart, literally. The inboard engine on the starboard wing tumbled free after cannon hits. It was horrible to see.

There's other instances, but this shows that an aircraft under fire is subject to damage - in some cases, catastrophic damage.

 

[Tord55]

P-61A:

Eliminate the gunner and the turret. Put the pilot and radar operator under a tandem canopy, that is jump right to the P-61E configuration. Getting rid of the turret and gunner would probably save close to a ton in empty weight, twenty percent in zero-lift drag, and months in development

Tandem-seating has proved over and over as draggier than side by side (see Hawker Hunter, Skyraider, and many more). The ideal in sub-sonic speeds are quite corpulent fuselages unless we are talking laminar flow, at transonic speeds.

 

[tyrodtom]

I about got caught by a stall on final in a Piper Cherokee.
Cross wind , turned from base to final a little late, tightened the turn too much to try and line up with the runway.
Horn went off, aircraft shook a little, and I eased out of the bank, put the nose down a little, then lined up late on final.
I almost landed short. A experienced pilot who observed my landing was pretty critical of my performance.

I should have aborted that landing and went around.
That's same scenario has killed a lot of people.

If I had had two people in the rear seat, and luggage, I probably would have not have had enough control authority to ease the bank, or lower the nose.

 

[Tord55]

I would have liked to have seen the Spit reach it's full potential. The interim models were needed, MkV-IX-XIV but I can't help but think the blooding of the spit in 1941-42 by the likes of the FW190A would not have happened if the MkIII running 2 stage Merlin XX's could have been made.

Bigger, better flaps would have made a hell of a change, too!

 

[BiffF15]

The slightly aft CG after ammunition was expended did not affect approach or landing. Or any normal maneuvers for that matter, just post-stall. P-39 was as safe as any other AAF fighter.

P39Expert,

If the P-39 was as safe as other fighters why did it have a reputation for tumbles / squirrely handling, or why did the USAAF do a spin demo film on it AND show one crash?

Hint: the crash was at the end as a punctuation point to the novice fighter pilots, a poke in the chest if you will.

Just because a person repeats something DOESN'T make it true no matter how many times it's said.

Also realize there are actual experienced pilots on here who can and do refute erroneous statements so please don't take it personal.

V/R,
Biff

 

[P-39 Expert]

P39Expert,

If the P-39 was as safe as other fighters why did it have a reputation for tumbles / squirrely handling, or why did the USAAF do a spin demo film on it AND show one crash?

Hint: the crash was at the end as a punctuation point to the novice fighter pilots, a poke in the chest if you will.

Just because a person repeats something DOESN'T make it true no matter how many times it's said.

Also realize there are actual experienced pilots on here who can and do refute erroneous statements so please don't take it personal.

V/R,
Biff

Biff, if I took any of this personal then I wouldn't continue to post on this board.

Virtually every AAF pursuit pilot trained on a P-39. If they were as dangerous as some on here claim then their role as trainers would have been curtailed. It wasn't. Chuck Yeager's favorite plane (until he got a Merlin P-51). He also said he didn't know anyone who didn't like the the P-39, and all the people who made those adverse claims had never flown a P-39. That includes the pilots who post on here.

And deliberate spinning was prohibited in virtually every AAF pilot's manual. The magnificent Merlin P-51 was a bitch in a spin too.

 

[XBe02Drvr]

If they were as dangerous as some on here claim then their role as trainers would have been curtailed. It wasn't.

It wasn't, because training command P39s were ballasted to keep CG away from the limits of the envelope, and didn't need as much aft mounted radio gear as combat zone planes did. This still didn't keep it from acquiring a "weirdo" rep amongst the pilots, as its ergonomics, its "feel", its handling, and especially its operating speeds were so different from the AT6s they were used to. Chuck Yeager was that rare nugget: a gifted "natural" from the get-go, who had the analytical mind, the disciplined approach, the confidence, and the reflexes and vision to quickly master a plane, and once past its quirks, appreciate its potential. Not a representative sample. I'm sure he appreciated its "hotrod" nature vs the Texan he'd been flying, and revelled in it, rather than be intimidated by it.
Ever wonder why so many P39s were stateside as fighter trainers when so many fighters were needed in combat theatres? They weren't actually optimum for the job, as their handling characteristics were so different from the advanced trainers and frontline fighters the students had come from and would go to, but they were available stateside, while every P40, and later P47 and P51, was urgently needed for combat. Makes you wonder, doesn't it?

 

[P-39 Expert]

It wasn't, because training command P39s were ballasted to keep CG away from the limits of the envelope, and didn't need as much aft mounted radio gear as combat zone planes did. This still didn't keep it from acquiring a "weirdo" rep amongst the pilots, as its ergonomics, its "feel", its handling, and especially its operating speeds were so different from the AT6s they were used to. Chuck Yeager was that rare nugget: a gifted "natural" from the get-go, who had the analytical mind, the disciplined approach, the confidence, and the reflexes and vision to quickly master a plane, and once past its quirks, appreciate its potential. Not a representative sample. I'm sure he appreciated its "hotrod" nature vs the Texan he'd been flying, and revelled in it, rather than be intimidated by it.
Ever wonder why so many P39s were stateside as fighter trainers when so many fighters were needed in combat theatres? They weren't actually optimum for the job, as their handling characteristics were so different from the advanced trainers and frontline fighters the students had come from and would go to, but they were available stateside, while every P40, and later P47 and P51, was urgently needed for combat. Makes you wonder, doesn't it?

Yes I really do wonder. Half of them went to the Soviets where they won the war and the other half were used as trainers here. And ANY combat plane would be a major step up from an AT-6 Texan.

You can keep grasping for any straw and rumor to somehow make the P-39 a deathtrap, but in reality it was a very serviceable combat plane. Do you consider the F6F Hellcat to be a good plane? Scourge of the Japanese and kings of the Pacific. Shot down more Japanese aircraft than any other plane. Look at the attached graph (wwiiaircraftperformance.org) with P-39N performance overlayed in red. Pretty competitive, no? And consider that the P-39N was out of production before the Hellcat had it's first combat with the USN.

 

[PAT303]

No sarcasm - I just recently watched some Luftwaffe guncam footage and in one segment, a Bf110G-2 closed in a B-24 and tore it apart, literally. The inboard engine on the starboard wing tumbled free after cannon hits. It was horrible to see.

There's other instances, but this shows that an aircraft under fire is subject to damage - in some cases, catastrophic damage.

Plus you need to add the aerodynamic loading G forces etc, there are many video's of aircraft being hit while turning hard and suddenly having a wing fold or pitch up into a stall and drop like a lead fart, as a former heavy vehicle mechanic I didn't see many driveshaft failures but when it did happen the damage was catastrophic, having a universal joint fail while hauling a load at very slow speed, like pulling away from the lights meant the engine immediately redlined and the tail shaft thrashed the underside to pieces, the energy released and the damage it causes has to be seen to be believed, I cannot image an aircraft can go through an entire war with a 12' driveshaft through it's middle not having a failure, whether by mechanical failure or by battle damage, the shaft is simply to big a component to not be hit by enemy fire.

 

[PAT303]

while every P40, and later P47 and P51, was urgently needed for combat. Makes you wonder, doesn't it?

That one line describes the P-39, if it was such a war winner why didn't it go to war?

 

[GrauGeist]

Bill Overstreet (P-51C pilot) absolutely hated it.

And in a twist of irony, the only American P-39 ace, Bill Fiedler, was killed by a P-38 - while sitting in the cockpit of his P-39 on the ground.

 

[swampyankee]

The P-39 and P-63 did go to war, it's just that the war they seemed to be good at fighting wasn't the war that the US or Commonwealth were fighting. In the Pacific, it really didn't have the range (or carrier compatibility) to be much use in the island-hopping campaigns and its range may have been an issue with its lack of use in the China-Burma-India theatre. It's also entirely possible that it, like some other aircraft, was competitive against German aircraft but struggled against the Japanese ones.

 

[Milosh]

Yes I really do wonder. Half of them went to the Soviets where they won the war and the other half were used as trainers here. And ANY combat plane would be a major step up from an AT-6 Texan.

The AT-6 wasn't exactly a docile a/c.

Talk to ten different people with first-hand knowledge of a particular aircraft and you get ten different accounts of the same aircraft. Not so with the T-6 "Texan". All agree the Texan had some terrible flight characteristics (fairly normal for a low wing monoplane of the mid 30's),

 

[GrauGeist]

The AT-6 (aka T-6/Harvard/SNJ/etc.) has quite a legacy for a 1930's aircraft, being used by dozens of nations for everything from training to combat, finally being retired by several air forces in the 1990's.

Not many interwar aircraft types can lay claim to that notoriety.

 

[swampyankee]

Tandem-seating has proved over and over as draggier than side by side (see Hawker Hunter, Skyraider, and many more). The ideal in sub-sonic speeds are quite corpulent fuselages unless we are talking laminar flow, at transonic speeds.

The problem with the P-61 wasn't tandem vs side-by-side seating, it was that the center nacelle was sized for three crew members and a bulky turret. The P-61E/F-15 nacelle was significantly smaller than that of the other P-61 models.

 

[BiffF15]

Yes I really do wonder. Half of them went to the Soviets where they won the war and the other half were used as trainers here. And ANY combat plane would be a major step up from an AT-6 Texan.

You can keep grasping for any straw and rumor to somehow make the P-39 a deathtrap, but in reality it was a very serviceable combat plane. Do you consider the F6F Hellcat to be a good plane? Scourge of the Japanese and kings of the Pacific. Shot down more Japanese aircraft than any other plane. Look at the attached graph (wwiiaircraftperformance.org) with P-39N performance overlayed in red. Pretty competitive, no? And consider that the P-39N was out of production before the Hellcat had it's first combat with the USN.

P39 Expert,

Okay, the P39 versus F6F comparison is really not that good.
A. The P39 wasn't carrier capable, wasn't able to carry the bomb load, nor did it make as many aces as did the F6F.
B. Range?
C. Grumman was known for making great flying planes. Did the F6F have any problems qualifying on the carrier, did the guys complain about it biting them in any manner similar to what the P39 experienced? The F6F was a large plane due to performance requirements as well as carrier operations imposed weight penalties.

Guys have spent a LARGE amount of time on here trying to show you where you are making assumptions that are not correct, or coming to conclusions based on incomplete or incorrect data.

Your ability to ignore facts, or information you don't agree with is TREMENDOUS.

Good luck.

V/R,
Biff