Diving - which fighters used it best, and how?

barney said:

To me, when we talk of diving, I don't think of a shallow dive to drop a bomb or strafe an airfield, I think of the monumental dives from bomber altitude to deck chasing or being chased by e/a.

When entering a dive, most planes had to be trimmed a certain way, altitude and speed had to be monitored and the pullout begun at a specific altitude depending on the speed and altitude where the dive was initiated. I can imagine this easily going wrong in combat.

So, I suggest the best diver would be the plane most likely to keep you alive when the execution of this maneuver is less than perfect. Better yet, I think a wise pilot in chase would feign the vertical dive and then go shallow. Let the guy below display his diving skills.

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That's pretty much exactly right. Did you know the Navy even had a way of monitoring the angles of the dives? The pilots got their initial training in dive-bombing in the SBDs in the Gulf and the Atlantic. My Dad got his out of NAS Okalaka.

VBF-13 said:

I beg your pardon? Why don't you research NAS Fallon, NV, late-1944, early-1945, for starters. Find out what the boys over there in those bombing-fighting squadrons were training on. I'll give you a hint, it wasn't just gunnery target practice and acrobatics. The F6Fs were made to dive-bomb, that was a built-in role. They were bombing-fighting aircraft, not just fighting aircraft.

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OK, now you boys got me talking to myself, replying to myself. I think this is useful to know, however. So, here we go...

Let's get our heads out of Wikipedia for a moment and try to get a grasp on the big picture. Why was Leroy Grumman put to the task of the F6Fs? One reason, to neutralize the Japanese air power. Grumman was the most logical choice for that as he was the manufacturer who was the most familiar with carrier constraints. Let's talk about those for a moment. One is, space. That meant not only the retractable wing designs, but pack as many roles into that aircraft as you can. When the mission priorities change, you want the machinery, right there, on board, to do the job. That's the reason those bombing capabilities were built into this fighter aircraft. Another is, maintenance. You want something simple. Another is, durability. You want something strong. The F6Fs filled out those constraints, as well.

OK. Indeed, the first F6F squadrons were VF (i.e., fighting) squadrons. Why? That was the priority. You don't drop bombs on enemy aircraft, you fight them. As that priority transitioned to encompass bombing, understand, these pilots had already been trained on that, well before the F6Fs even came out of production. They got their wings, they went straight to the SNJs, then to the SBDs. They already knew how to dive-bomb. And, indeed, those later F6F squadrons were VBF (i.e., bombing-fighting) squadrons.

Finally, on the subject of this thread, generally, I'll implore you all to think of this. You take any of these aircraft discussed, you put a pilot in there who knows what he's doing, he's going to put that bomb on the pitcher's mound on a baseball diamond. That's how good these aircraft were in that role. All they required was that crack pilot. How do you think our SBDs got those carriers at Midway? And, note, those weren't standing still like land targets. I rest my rant.

My father has officially documented in combat reports that his P-47 regularly did up to 600 mph in a dive and needed to apply his dive brakes to stop from overtaking the fleeing kraut in front of him.
When Gladych and he joined the 56th FG after flying spits in various Polish squadrons, they were asked to assess the combat capabilities of the jug. To summarise, climbing and diving the best they had ever flown but very lacking in combat capability below 15,000 feet.
It was only the later marks of spit that were capable of safely diving at speed. Several Polish pilots were killed when the "wings marched off" (as my father stated) or the fuselage twisted out of line rendering the spit to the scrap heap. One Polish pilot 'Feric' is in Northolt runway having proved the point to the farnborough engineers that the wings separated in a steep dive. He was reported to have been killed in a 'flying accident'

Xjrtaz said:

Several Polish pilots were killed when the "wings marched off" (as my father stated)...

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My father told me that same thing in reference to the Kamikazes when they came in "hot" and yet nobody here believed it because I couldn't back it up in a Wikipedia reference or some such thing. Suffice it to say, I believe you.

Xjrtaz said:

My father has officially documented in combat reports that his P-47 regularly did up to 600 mph in a dive and needed to apply his dive brakes to stop from overtaking the fleeing kraut in front of him.

His impression of 600mph was due to the inability of the pitot tubes to correctly get true airspeed stagnation pressures and temperatures.

When Gladych and he joined the 56th FG after flying spits in various Polish squadrons, they were asked to assess the combat capabilities of the jug. To summarise, climbing and diving the best they had ever flown but very lacking in combat capability below 15,000 feet.

It was only the later marks of spit that were capable of safely diving at speed.

Actually, no. While the Spit attained .89M and the P-51 and P-47 attained .85M, those speeds were far from "Safe". Many of all three of those ships were written off after RTB and the ones that didn't return - crashed.
Several Polish pilots were killed when the "wings marched off" (as my father stated) or the fuselage twisted out of line rendering the spit to the scrap heap. One Polish pilot 'Feric' is in Northolt runway having proved the point to the farnborough engineers that the wings separated in a steep dive. He was reported to have been killed in a 'flying accident'

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Even the P-51 and P-47 which were the top divers for US were 'restricted' at 505mph TAS and/or .75M.

Xjrtaz said:

My father has officially documented in combat reports that his P-47 regularly did up to 600 mph in a dive and needed to apply his dive brakes to stop from overtaking the fleeing kraut in front of him.
When Gladych and he joined the 56th FG after flying spits in various Polish squadrons, they were asked to assess the combat capabilities of the jug. To summarise, climbing and diving the best they had ever flown but very lacking in combat capability below 15,000 feet.
It was only the later marks of spit that were capable of safely diving at speed. Several Polish pilots were killed when the "wings marched off" (as my father stated) or the fuselage twisted out of line rendering the spit to the scrap heap. One Polish pilot 'Feric' is in Northolt runway having proved the point to the farnborough engineers that the wings separated in a steep dive. He was reported to have been killed in a 'flying accident'

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Your father assessed the P-47 as the best climber he'd flown to date? Did he mean zoom climb?

drgondog said:

Originally Posted by Xjrtaz
My father has officially documented in combat reports that his P-47 regularly did up to 600 mph in a dive and needed to apply his dive brakes to stop from overtaking the fleeing kraut in front of him.

His impression of 600mph was due to the inability of the pitot tubes to correctly get true airspeed stagnation pressures and temperatures.

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Are you saying the pitot tube can't measure true air speed in a dive? I never heard of that. Air speeds were measured all the time in diving training.

At any rate, his father's impression he regularly had to apply his dive brakes while descending on a fleeting fighter means to me he had that P-47 cooking pretty darn fast.

VBF-13 said:

Are you saying the pitot tube can't measure true air speed in a dive? I never heard of that. Air speeds were measured all the time in diving training.

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Compressibility error -
The error in the readings of a differential-pressure-type airspeed indicator due to compression of the air on the forward part of the pitot tube component moving at high speeds.


Read more: compressibility error: Definition from Answers.com

CobberKane said:

Your father assessed the P-47 as the best climber he'd flown to date? Did he mean zoom climb?

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Yes, best one to date.
After the war he flew jets with 167 Sq

FLYBOYJ said:

Compressibility error -
The error in the readings of a differential-pressure-type airspeed indicator due to compression of the air on the forward part of the pitot tube component moving at high speeds.


Read more: compressibility error: Definition from Answers.com

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Thanks. I suppose then I can say at slower speeds it's more reliable? I don't understand the science, that's why I'm asking.

VBF-13 said:

Thanks. I suppose then I can say at slower speeds it's more reliable? I don't understand the science, that's why I'm asking.

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For the most part yes. On some installations there is actually a correction card that will account for compressibility error

FLYBOYJ said:

For the most part yes. On some installations there is actually a correction card that will account for compressibility error

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Appreciate it, FLYBOYJ. I honestly never even knew there was an issue there.

Even if there wasn't an iota of data to support it, the anecdotal evidence from both sides of the conflict would be enough to secure the Thunderbolts reputation as one of the best divers of the war. The RAE established that other aircraft, including contemporary 109s and 190s, had outright higher diving speeds, but possibly that wasn't much use in practice because if the P 47 accelerated in the dive as quickly as it's pilots said, it would have overhauled those fighters while they were still building up speed. Maybe that's where the P47's great strength lay; in dive acceleration from a typical combat manouvering speed up to, say 500mph, combined with its steadyness as a gun platform at those speeds. The specific adavantage of a 109 or 190 in outright eventual dive speed wouldn't be much use if it had a P47 up its clacker filling it with .50s while it was waiting to get there.

Xjrtaz said:

Yes, best one to date.
After the war he flew jets with 167 Sq

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Gotcha. I would have been very suprised if your grandfather had been singing the praises of the P-47 as a climber afer coming from Spits, but as a zoom-climber it was supposed to be very good. The Tempest may have been better still, though it couldn't go as high as the 47, and probably came along a bit late in the war to really cement its reputation.

CobberKane said:

The RAE established that other aircraft, including contemporary 109s and 190s, had outright higher diving speeds, but possibly that wasn't much use in practice because if the P 47 accelerated in the dive as quickly as it's pilots said, it would have overhauled those fighters while they were still building up speed. Maybe that's where the P47's great strength lay; in dive acceleration from a typical combat manouvering speed up to, say 500mph, combined with its steadyness as a gun platform at those speeds. The specific adavantage of a 109 or 190 in outright eventual dive speed wouldn't be much use if it had a P47 up its clacker filling it with .50s while it was waiting to get there.

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Kobber - do you have those reports from RAE? You may recall Gunther Rall was assigned to Rechlin during rehab where he both flew the P-51, P-47 against the latest LW ships during the Fighter School part of his assignment there but also had access to all the test pilots and data. He was very clear in his autobiography that he could not escape in a dive against the chasing 47s.

Another factor to consider is that if the 109 or 190 began a dive to evade say 800-1000 yards ahead of a 47 or 51, and was truly faster in a dive, there would be no hope of the P-47 (or P-51) catching up - and yet catch up they did (and often) as evidenced by so many Encounter reports.

The drag coefficient of the P-51 was 2/3 of the 109/190...which leads to interesting questions regarding the RAE tests.

As far as wings ripping off one has to account for different variants that had different armaments in the wings. More guns.....heavier wing that would come off more easily than a wing with less guns in it. I believe in testing either a version of the mustang or even the jug shed its wing because of steps taken to lighten the aircraft and less guns were put in to compensate until the wing root was strengthened. Can't remember where I read that but I will check my "jug bible" when I get home tonight.

Arossihman said:

As far as wings ripping off one has to account for different variants that had different armaments in the wings. More guns.....heavier wing that would come off more easily than a wing with less guns in it. I believe in testing either a version of the mustang or even the jug shed its wing because of steps taken to lighten the aircraft and less guns were put in to compensate until the wing root was strengthened. Can't remember where I read that but I will check my "jug bible" when I get home tonight.

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Two Mustang wing failures (P-51) were traced to landing gear lock failing in high G pull - in which the gear door was popped open, one suspect was due to ammo doors failing at very high speed. Production fits were made to provide LG uplock and redesigned door from B to D as wellas replace .188 thick ammo door with .25 thickness.

Most failures of the 51 were in rolls for which there were large asymmetric loads. The only 51 that had conscious weight reduction program was the P-51H - it was designed to 7 1/2 G at 8800 pounds IIRC which was a higher stress Design Limit Load than the P-51B/D at 8G for 8000 pounds GW

drgondog said:

Kobber - do you have those reports from RAE? You may recall Gunther Rall was assigned to Rechlin during rehab where he both flew the P-51, P-47 against the latest LW ships during the Fighter School part of his assignment there but also had access to all the test pilots and data. He was very clear in his autobiography that he could not escape in a dive against the chasing 47s.

Another factor to consider is that if the 109 or 190 began a dive to evade say 800-1000 yards ahead of a 47 or 51, and was truly faster in a dive, there would be no hope of the P-47 (or P-51) catching up - and yet catch up they did (and often) as evidenced by so many Encounter reports.

The drag coefficient of the P-51 was 2/3 of the 109/190...which leads to interesting questions regarding the RAE tests.

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Unfortunately, I don't have the reports. I'm going on the account of Eric Brown in his book. But I agree that in practise a P-47 could out dive pretty much anything, either offensively or defensively – all the pilot accounts I've read from both sides of the conflict confirm it.
From what I've read the P-47 accelerated very quickly in the dive and retained the speed it built up very efficiently, either of which characteristics would enable it to overhaul a fleeing opponent, either during the dive or immediately afterwards, irrespective of whether the other plane might have had a slightly higher maximum dive speed under controlled circumstances. My thinking is that even with a fairly extended separation these qualities must have been enough to give the P-47 a significant edge in the area of diving. The alternative would be to assume the RAE results were wrong, which I'm disinclined to do

I pressed Wing Captain Brown on this topic back in the 80's and could get no back up to his claim that the Mcr of the FW 190 was higher than both the P-47 and P-51, enabling it to dive faster. I'm open to belief that RAE tested all three to critical limits but I have only found the Mustang IV and P-47D-30 (?) dive tests (with wing flap), which given all the access via internet is pretty curious that the results for 190 and 109 are not available.

As to accelerating in a Dive - and then extending the lead - the Mustang out accelerated the Spit IX at all altitudes then maintained the separation, the Tempest V above 24000 feet (the Tempest slightly superior below 24,000 feet), the FW 190 and Me 109G always at all altitudes according to the RAF Wettering report dated 8 March 1944. These are the only published Tactical Comparisons I have seen.

Page 58-61 of Jeff Ethell's "Mustang"

The Army Air Forces Board Project No. (M-1) 50 "Tactical Employment Trials on North American P-51B-1 Airplane" was a Tactical Trial between the P47D-10, P-38J-5, the P39N-0 and P-40N.

Comments - regarding individual characteristics in which the Mustang was out performed.
1. Both the P-39 and P-40 had a slightly better turn.
2. The P-47 had a slightly better rate of Roll, but the P-51 has a faster rate of roll than all the others
3. It notes that only the P-38J can initially out-accelerate (to a couple of hundred feet in front), before being rapidly caught from behind by the 51 from level flight.
4. The P-38 and P-51 are even in Zoom cimb initially from level flight at low and medium speeds, but the P-38 keeps climbing after the 51 falls away. At high speeds however the 51 pulls away and zoom ends 'considerably higher'.
5. The P-51 out zooms the P-47 from level flight at all speeds, and recovering from dives the P-51 out accelerates and outclimbs the 47.
6. The P-47 is slightly faster than the P-51 above 30,000 feet but the Mustang will attain 400 mph all the way to 40,000 feet.

One other important note - "The P-47 and P-51 are equal in Dive from level flight but the P-51 'jumps ahead several hundred feet' then maintains that separation neither gaining nor losing distance."

Inference - if the FW 190 and Me 109 have a superior dive speed according to Brown to both the P-51 and P-47 then the acceleration period to terminal dive velocity should be a pretty short interval - implying that neither the Mustang nor Thundebolt should Ever catch the 109/190 in a dive initiated from equal altitudes if the German fighters have several hundred yards of separation. History is unkind to that theory.


Pages 49-50 from Jeff Ethell's "Mustang" - I haven't looked but think this report is on SpitfirePerformance website.

The net of the discussion is there seems to be no published comparisons citing the Fw 190 or Me 109 as superior either in dive acceleration or max dive velocity to either the Mustang or Thunderbolt.

Must say, some really interesting posts on this thread. great stuff all, very knowledgeable, hats off to you all