Which performance aspects of a fighter were most crucial?

[GrauGeist]

Just something to think about here...

My uncle started out with the P-36 and as the war got underway in the Pacific, was assigned briefly to the P-39 and then the P-38 for the duration.

He hated the P-39 with a passion and spoke highly of the P-38. However, his passion was the P-36 and said that had it been armed better, it would have been a deadly adversary to the A6M NOT because of speed but it's ability to hold it's energy in a turn. His thoughts on engaging an adversary were that speed allowed you the luxury of dictating when and where you confronted the enemy but being able to out perform the adversary was #1.

In otherwords, you can be the fastest ride on the block, but that doesn't mean sh!t unless you can take down your opponent...

 

[GregP]

I hadn't heard it quite like that before, Graugeist, but though I believe speed to be important, I'm don't rank it number 1 in flight characteristics. It's nice to near it from another source other than the pilots I have heard speak on their experiences.

Not to change direction, but we have a local fellow here who is building a P-36 for himself. That would be Matt Nightengale. You can bet I'll post pics when it flies!

 

[GregP]

Early Viet Nam was a study in how not to use fighters and tactical air correctly. Later they improved, probably through total embarrassment.

 

[davparlr]

Historically, the one design criteria most emphasized in the development of the aircraft, including fighters, is increasing speed. Biff already mentioned the Me 262, but many other examples exist where speed alone changed the equation, the mono wing quickly made biplanes obsolete, retractable gear did away with fixed gear, swept wing Migs chased the slower F-80/F-84/F9F/F2Hs out of the dogfight. Powerful engines made subsonic fighters obsolete. Biff already explained the Hiccup the Mig-17 caused in Vietnam due to poor missiles, poor tactics, and poor training. Only when the adiabatic heating of the air approached the weakening point of aluminum, around Mach 2, has this pursuit of higher speed slowed down. It did shift to cruise speed where supersonic cruise became important. Energy level has also been mentioned which is a function of altitude (potential energy) and speed (dynamic energy). Speed, however is squared function whereas altitude is linear. Doubling speed quadruples energy, an important factor in combat maneuvering.

 

[drgondog]

Just something to think about here...

My uncle started out with the P-36 and as the war got underway in the Pacific, was assigned briefly to the P-39 and then the P-38 for the duration.

He hated the P-39 with a passion and spoke highly of the P-38. However, his passion was the P-36 and said that had it been armed better, it would have been a deadly adversary to the A6M NOT because of speed but it's ability to hold it's energy in a turn. His thoughts on engaging an adversary were that speed allowed you the luxury of dictating when and where you confronted the enemy but being able to out perform the adversary was #1.

In otherwords, you can be the fastest ride on the block, but that doesn't mean sh!t unless you can take down your opponent...

Dave - my point is that the thread was about "Which Performance Attributes Were Most Critical"

My observation about your uncle's comments are twofold. First, after flying the P-38 would he have chosen a 'new P-36' with better armament? Second, would he have liked to fight the A6M with a P-38 absent turbosuperchargers. That version of a P-38 doesn't do well against any front line adversary as the P-322 would not have (and RAF recognized such) done well against anybody. The Difference? Top speed across the entire performance envelope, which in turn drove excess power available over drag for climb and turn performance - given the same wing and gross weight.

I am fully aware that maneuverability is extremely important, but for WWII increase in speed (and Range) was driving US fighter designs. The aircraft that failed to achieve the AAF spec on speed failed to become front line fighters. For the USN, speed was important but Carrier Qual/low speed handling characteristics were equally important - which is why the USN held back on F4U and initially gave them to USMC. The Brits on the other hand, looked at F4F and Martlet, looked at F4U - and said 'no brainer'.

Case in point - when the P-51 was upgraded with the Merlin, the handling characteristics suffered as well as relative turn rate maneuverability comparisons versus the P-40 and P-39. At no time was NAA asked to re-design the P-51B/D wing to restore turn comparison or increase climb via increased wing area. They ultimately achieved both by reducing the weight of the P-51H and reducing the drag while increasing HP - and speed.

The F4F could close on an F4U in less than a full turn - but lost every other attribute for combat usefulness. The A6M was arguably the best fighter in the world in 1942 and brutalized everything we put up against it - because its speed was near equal but had every other maneuver attribute except dive in its favor (possible exception P-36 according to your uncle). When our much faster fighters arrived in PTO, the tables were turned even though the Zero still held most of the maneuverability advantages in a dogfight - if our fighters chose to engage. The Tactics were modified to capitalize on the big advantage - Speed.

To your uncle's example, the P-36C was the last production ship with top speed of 313mph, W/L of 24psf and max climb rate of 3400 fpm. The A6M mod zero-21 of 1941 was about the same overall performance, much heavier firepower, edge to P-36 for dive.. good match.

Take it to Europe or Russia and see how it does against the 109F which was 80mph faster, But had a greater W/L, same ROC, greater dive speed and greater firepower? P-36, like the P-39, like the P-40 could all out turn the 109F/G - but how did they perform against the front line German (or A6M) until the P-47, P-51 and P-38 arrive in numbers.

My point, which I am sure will elude the other guy in this debate, is that Speed requirement was first or near first on the Specs and RFP's. Top Speed drives the aerodynamics and thus the wing airfoil and fuselage lines as well as Power plant. If Power plant a given (i.e. Allison for in-line until 1942 when Merlin was 'possible, or R-2800 for radial fighters after P-36 and F4F were obsolete). Range drives aerodynamics, weight, fuel load, W/L and AR. Take off and landing drives wing area, flap considerations, empennage sizing - and also increases weight and drag, thereby lowering speed for same power available.

Requiring iterations and design compromises regarding the secondary factors. For USN lading speed and takeoff length was Not secondary - but landing speed over the fantail Did drive empennage and flap and wing area - necessitating compromise of top speed absent those considerations.

But picking big wing, high AR and big fuel load increases drag, lowers climb and turn and lowers top speed. BTW, the F6F was a leap over the F4F but fell short of the F4U except for turn rate.

My only point is that designing a single engine Fighter during WWII focused on the initial attributes of top speed attainable while factoring in the Range/fuel load/AR/GW on one hand and Flap Area, elevator and rudder for low speed mandates on the other.

Neither the AAF nor USN started with Max Turn Rate or even Max Climb rate as those attributes, after optimal fuselage and wing design were conceived, could then be factored in by sacrificing top speed in your conceptual design - or reach an unacceptable Speed capability and start major compromises on Range or Ceiling (both MUCH more important that Rate of Turn and Climb(both of which is driven by Excess Power available, Lift CL, Wing area and Drag).

BTW the P-38 Spec was driven by 1.) Top Speed, and 2.) Rate/time of Climb and 3.) Ceiling which is why only a fat wing, twin turbosupercharged engine configuration would work in 1938. The Fat Wing compromised top speed later on as well as controllability in a dive - both of these learning experiences translated into a better design with the F7F, even though the F7F also had to build Carrier Qual into wing/flap, GW and tail design that the P-38 didn't have to worry about.

Thanks, Dave for the anecdote from your uncle..

 

[GrauGeist]

You know, Bill, I honestly think he would have dropped the P-38 if he could have gotten back into a P-36.

He honestly felt that there was a great deal of overlooked potential and when people would point out that the P-40 was just a "P-36 with a water-pumper" he'd reply with "Bullsh!t...night and day!"

As far as his P-38 experiences versus IJN/IJA adversaries, he certainly used speed to his advantage, it was a great tool for ambush just as much as it was a great tool for survival when things got a little too "hot". While his rides may have been roughed up on a few occasions, he was never shot down, so he definately knew his (and his opponents) limitations.

Perhaps he was a bit "old school", he did have his start with the USAAC, after all...

 

[drgondog]

I'd say, Bill, that if one had a choice between a P-40 and P-51, the choice would be obyious, and please note I didn't ever say anybody would pick a P-40 over a P-51. Where exactly did that come from?

Why obvious Grep? The primary performance difference between a P-51 and the P-40 was speed with the same engine, but the P-40 had a slightly better roll and turn rate. The P-51B with the Merlin gained in Excess Power to increase Speed despite GW increase and also increased climb - but turn and roll remained with the P-40? So which performance attribute do you not like about the P-40?

Since I'm an engineer, I'm well aware of the formula for kinetic energy.

Ah, so you say. But you demonstrate zero grasp when differentiating MV with respect to time Somehow the concept of the climb performance characteristics between the P-51H and D seemed to elude you, as well as the features of lower drag when comparing same power - but perhaps a quick refresher in Physics 101 would help you to move on to Free Body diagrams.

Anybody who thinks about it doesn't expect a spec for fighting at medium speed. But you NEVER get the chance to get to maximum speed if you are bounced or if the bombers you are escorting are bounced while you are cruising overhead.

In a word BS. Most folks knowledgeable in the tactics of WWII escort fighters will comprehend a roll and split S to follow an attacker - or a turn into a diving attacker followed by a reversal into a diving turn. Are you serious Greg. Go back to the Energy equations you speak so knowledgeably about above? Recall Energy is both a function of Kinetic and Potential (based on elevation datum)Energy? So what happens Greg when said fighter converts Potential Energy by initiating a dive and chase? Does it slow down? Does it find an equilibrium at an intermediate speed - or quickly approach top level speed - and beyond?

You get bounced at whatever speed you are going at the time. Your ability to get to maximum speed will be zero unless you roll over and head for the ground immediately. If the guys who bounced you come from above, they are already much faster than you and are no doubt back above you and can probably catch you anyway even if you accelerate with WER power.

So, back to US Fighter Tactics 101 - when attacked from above, make an immediate turn into the attacker and then follow - or not - into a dive to chase. The Germans largely were familiar with Your tactic and repeatedly attempted to dive away from an attack from above - such tactics were often successful in the East, were occasionally successful during BoB with the carb set up of the Merlin, but rarely successful against the faster US fighters (exception P-38 )

I suppose we'll just have to disagree.

You keep saying that - but keep repeating silly statements - then saying that. Try this. Gather Facts - historical or mathematical-engineering. Leave anecdotes alone, you're not good at it, you don't source them, and you don't frame them with context.

And you should get your head back to the bombers since that was the primary mission of the P-51 in the ETO, unless we read completely different histories. What was aked about were the important qualities of a fighter in order.

I truly wonder if you are well read on ETO history, tactics and objectives. I truly doubt it. I recommend (Highly) that you Google "The Long Reach - Deep Fighter Escort Tactics", published by VIII Fighter Command, 29 May 1944. If you can't find it, I have reproduced in "Our Might Always, starting page 496, about 10 pages from Hub Zemke, Everett Stewart, and others discussing ALL aspects of the mission, the formation tactics, the engagement processes, and most of all - the ATTITUDE which is Attack. If you understand what the leaders of those escort fighters convey to you, you will stop blathering

I never said speed wasn't important, I said it wasn't at the top ... and I don't think it is. If so, then surely a follow-on fighter should be faster than the one before it. That hasn't been the case since the F-15 came out 40+ years ago. I don't think an F-22 can catch an F-15. But it has WAY better avionics and can make moves an F-15 can't.

All true - but the top speed and cruise speed for a Stealthy airframe was the top airframe spec for the F-22. It represented a quantum leap over the F-117 which was its progenitor - not the F-15.

The F-15 was preceded in design approach by the F-16 (Extension of Lightweight Fighter Concept) but flew first and its primary difference (both designed for high top speed was the radar dish size which gave the F-15 a greater threat capability air to air in stand off - but required a bigger airframe and more power to approach the F-16 air to air maneuverability. Nobody in the USAF that flies the Lawn Dart is particularly awed by the F-15, F-14, F-18 but it can't 'see' as far to engage air to air missles in stand off as the F-15

There were versions of the Bf 109 that, at the right height, were faster than a P-51. I'd still take the P-51, myself. The Spitfire also wasn't the fastest steed in the cloest, but I'd take one if I knew I was in for a fight.

And there was a version (P-51H) that was faster than the 109K-4. The mark XIV was slightly faster than the P-51B (all versions) and as fast as the 109K-4 but would out turn and out climb both. So, may we remind ourselves that the focus was to shove more HP into same airframe to get more SPEED.

We very probably have the same characteristics in mind for a fighter, but don't have them quite in the same order you do and likely won't. I don't need a re-education every time we talk with one another. We see much the same information with a slight shuffle of what was more important. In the relative world of personal opinion we really aren't all that far apart since we both see to be fans of the same war.



I sort of like it that we have different opinions because it keeps it interesting.

Actually we are often quite far apart with respect to historical perspectives, flight characteristics, engineering comparisons and debate styles. What I find most objectionable is your repeated failure to bring true engineering/fact based arguments into any discussion, where such approach is required.

 

[Shortround6]

You know, Bill, I honestly think he would have dropped the P-38 if he could have gotten back into a P-36.

He honestly felt that there was a great deal of overlooked potential and when people would point out that the P-40 was just a "P-36 with a water-pumper" he'd reply with "Bullsh!t...night and day!"
:

From a few things I have read the P-36 was a delightful airplane to fly. It's controls were supposed to be better co-ordinated than an early Spitfire. But the Early Brewster Buffalo was supposed to be quite nice to fly also.

Many pilots claimed they were "ruined" as newer versions came out. But the early planes, while nice and responsive to fly, weren't very good warplanes. Unfortunately heavier armament, armor, selfsealing tanks all impacted not only speed and climb but turning ability. Center of gravity may have shifted, not to the point of being unsafe but enough to affect control response. Or in the case the P-40 the longer nose (or weight further from the CG even if in balance) caused a slight delay in control response?
Beefed up structure to handle the heavier weights also hurt. The P-36 may have had "potential" but even sticking four .50s in the wings (and ditching the fuselage guns) adding armor, adding self-sealing tanks id going to added hundreds of pounds to the P-36
and may cause it's handling to deteriorate.

 

[FLYBOYJ]

F-22 top speed, Mach 2.25 (estimated)
F-15 top speed, Mach 2.5

 

[drgondog]

You know, Bill, I honestly think he would have dropped the P-38 if he could have gotten back into a P-36.

He honestly felt that there was a great deal of overlooked potential and when people would point out that the P-40 was just a "P-36 with a water-pumper" he'd reply with "Bullsh!t...night and day!"

As far as his P-38 experiences versus IJN/IJA adversaries, he certainly used speed to his advantage, it was a great tool for ambush just as much as it was a great tool for survival when things got a little too "hot". While his rides may have been roughed up on a few occasions, he was never shot down, so he definately knew his (and his opponents) limitations.

Perhaps he was a bit "old school", he did have his start with the USAAC, after all...

He is right about the P-36 being in the same basic envelope as the A6M - but I doubt that he would be alive if he had the rank and the spare parts to insist on continue fighting with it.

My father and many of his friends and comrades that flew both the P-51B and D remarked that the D was a very slight step back in performance - all basically traceable to extra AN/M2 50's plus 400 more rounds of ammo. When I was old enough to understand the differences I did ask the questions - So, why didn't You as Squadron CO and having the pick of the airframes, including his P-51C-10NT with Malcolm Hood, choose to stay in it instead of taking the new P-51D and every succeeding D model after that? Second question - Do you know of a single fighter pilot that chose to fly the B/C when a D was presented for him, given a choice?

His answer "I liked the visibility and the firepower advantage, and the few fpm in climb or turn didn't offset the B performance advantage", and "no". The unanimous opinion of all the fighter pilots I talked to growing up and all the way through current days is that the P-51D was THE preferable Mustang to go fight with.

Nothing but respect for your uncle. There were also a lot of Finns that did very well with a Buffalo, so who am I to question their preferences?

 

[bobbysocks]

Many pilots claimed they were "ruined" as newer versions came out.

i have heard the same said by german pilots. several favored the 109F and thought the later models were too heavy, etc....

from the franz stigler interview...

Q. Your favourite was the F model, yet the one that was produced the most was the G6…

FS. Yeah…

Q…But most pilots preferred, like yourself, the F models and the earlier G's, like the G-2. What was the reason behind that?

FS. The G6 basically had a heavier motor and could fly higher…not more speed, but that's it…it starts getting heavier every time they put something new in.

 

[GregP]

Bill,

Apparently you lack the facility for civil discussion and are again resorting to condescending insults.

Why not try to discuss like an adult instead of resorting arguing like a child? I reserve the right to state my observations and opinions ... just the same as you do, and I can see that you seemingly must focus on our differences rather than what our observations have in common.

So, in the future please just just leave me alone and I'll reciprocate. Promise.

 

[pbehn]

F-22 top speed, Mach 2.25 (estimated)
F-15 top speed, Mach 2.5

How fast are the missiles carried by the F 22?

 

[BiffF15]

Pbehn,

I don't think those speed comparisons are correct (F22vF15). I could be wrong though...

The missile speed is a value of what it can generate PLUS the launch A/C Mach. The higher the launch Mach the faster the missile goes.

Cheers,
Biff

 

[FLYBOYJ]

Pbehn,

I don't think those speed comparisons are correct (F22vF15). I could be wrong though...

Got those from Wiki - it seems the F-22's top speed may be classified.

 

[drgondog]

Bill,

Apparently you lack the facility for civil discussion and are again resorting to condescending insults.

No, I do have the facility, and frequently the inclination. Look to the mirror however if you seek examples of the condescending and supercilious reposte while layered with abundant sweetness.

Why not try to discuss like an adult instead of resorting arguing like a child? I reserve the right to state my observations and opinions ... just the same as you do, and I can see that you seemingly must focus on our differences rather than what our observations have in common.

Now, I'm gonna cry. OK Greg, try going back to the multiple threads of blather that you have posted in this thread and try an exercise?

For every instance where you say Speed is not at the top of the AAF or RAF fighter design requirements, list your own - in rank - and tell us how the fighter(s) you wish to pose as examples, 1.) deviated from High Speed to 'XYZ' and 'ABC' to achieve the Requirements YOU think were more important, and 2.) show how those fighters attained dominance over both the target adversary as well as emerged superior to a comparable timeline competitor.

So, in the future please just just leave me alone and I'll reciprocate. Promise.

I blessed you a couple of posts back with the design approach that would be considered by the preliminary design team responding to an RFP - but if you don't like what I posted - well, knock yourself out with the Way They Really Did it after gleaning this knowledge from all the folks that you have 'heard at POF'.

Or, If I missed something in your resume, explain what exactly what you learned at Purdue (?) and how that background was honed in your career?

BTW - the F6F is a derivative or extension of the F4F design for both mission and application and you could on one hand state that top speed wasn't as important as 'xyz' but you would do well to remember that the F6F was considerably faster, but did not improve on turn performance, so what were they differentiating for their airframe design?

You might state that your fav, the P-40Q, is an extension of the P-40 - and it is. But why did they lay a laminar flow wing on it? It didn't improve turn or roll performance but was a significantly Faster fighter than ANY P-40. Why did Curtiss take a Speed driven design approach?

Express your opinion Greg! but why not step out of your mold and lay some facts around the discussion?

 

[pbehn]

Got those from Wiki - it seems the F-22's top speed may be classified.

I was just making the point that speed is important to break off an engagement by outrunning your opponent, in the jet age you must out run his missiles or break of its Radar/IR homing system.

 

[soulezoo]

F-22 pilots at Kadena, after mock dogfights with -15's, have told me in effect "the -22 is a little faster at the top than a -15"

It gets there faster too...

In same conversation, pilots were telling me it usually takes at least 3 and usually 4 -15's to take out a -22.

Comments made during maintenace debriefing.

Full disclosure: I am not a pilot and am only repeating what the pilots told me.

 

[grampi]

F-22 pilots at Kadena, after mock dogfights with -15's, have told me in effect "the -22 is a little faster at the top than a -15"

It gets there faster too...

In same conversation, pilots were telling me it usually takes at least 3 and usually 4 -15's to take out a -22.

Comments made during maintenace debriefing.

Full disclosure: I am not a pilot and am only repeating what the pilots told me.

I'd like to hear what they'd have to say about the 22 vs a 16...I'm sure the 22 is faster, but the 16 has got to be much more maneuverable...

 

[FLYBOYJ]

I'd like to hear what they'd have to say about the 22 vs a 16...I'm sure the 22 is faster, but the 16 has got to be much more maneuverable...

It probably is, but what good is all that maneuvability when you're targeted and killed from an aircraft 40 miles away that was never seen to begin with?