Navalized P-38 Lightning?

Scott Peterson wrote:

Guy Alcala wrote:

Certainly. I'll have to use the figures for the PBJ-1H, essentially the
marine version of the B-25H. With a bombload of 6 x 500 lb bombs plus the
75mm cannon and ammo, at a t/o weight of 35,106 lb. (considerably heavier
than Doolittle's B-25Bs), the t/o runs are as follows (note, this is for a
field not a carrier deck):

0 wind, 1495 feet.
15 knots, 1064 feet.
25 knots, 813 feet.

Nice of you to use a version that's almost 7000 pounds heavier.

The discussion was about the ability of a P-47 to make a free-running t/o from a
CVE. I used the heaviest weight B-25 data I had to show that even _that_
version only needed between 2/3rds and 3/5ths of the t/o run that a clean but
fully fueled and armed P-47 does (2,220 - 2,540 feet). Hell, the PBj-1H's power
on stall speed at that weight was only 93 knots (see Hornet WoD below).
Naturally, lighter B-25s like Doolittle's (about 31,000 lb. was the predicted
weight, or about 4,000 lb. less than the above -- see

http://www.ibiblio.org/hyperwar/AAF/...B-Special.html

have even shorter t/o runs, given them an even more significant advantage over
the P-47.

Please note that the Hornet was worked up to just about full speed, i.e.
30+ knots, and there was a considerable natural wind blowing when Doolittle
& Co. took off.

Glad it wasn't an unnatural wind. But so what? From what I remember
they were anticipating and trained based on about 40 knots over the
bow when they took off. That they got more was a bonus.

Here's so what. 40 knots WoD (combination of 'unnatural' wind, i.e. ship speed,
and natural wind) is considerably more than an 18 kt. CVE is likely to be able
to supply in the generally warmer and calmer tropics, while a 30+ kt. CV in the
North Central Pacific can almost guarantee it. Actually, checking Hornet's
after action report at

http://www.ibiblio.org/hyperwar/USN/...cv8-Tokyo.html

it seems that the Hornet was steaming at only 22 kts, as there was 40+ knots of
natural wind (see para. 1(j). of the above), for a WoD of 62kts or better. And
the lead a/c (Doolittle's) had a 467 ft. deck run available (para 1(g), same
ref.), i.e. 25 feet more than the_total_ length of a Bogue's flight deck (442
feet) and only 10 feet less than the total length of a Casablanca (477 feet). A
ferry carrier would have to catapult its entire deck load off first, before it
had anywhere close to that much t/o run available.

In point of fact, the Navy conducted flight tests using a slightly
modified P-51D (I think) on USS Shangrila in 1944. The plane was
easily able to take off using the same space as Navy fighters

And how, pray tell, was it able to "take off using the same space as a navy
fighter," when (even assuming the '1,185 ft.' figure for the P-51D's t/o
run given in "America's Hundred Thousand," is _not_ a typo) the
contemporary F6F-5 and F4U-1D only required t/o runs under the same
conditions of 780 ft. (405 feet less than the P-51D) and 840 feet (345 feet
less) respectively?


Apparenttly very easily. If you read the rest of the report you quote
below it mentions that they had deck left when they lifted on all the
takeoffs.

Not sure which report you're referring to. It's not in Brown's account which I
quoted. But how long was the deck run, exactly, what were the WoD conditions,
what did the P-51s weigh, and what were they loaded with (and where was the
Cg)? I'd be kind of surprised if the rear tank was filled.

and no
catapult and easily landed using a hook fitted for the tests. The
results were quite favorable but not compelling enough to continue.

'Quite favorable' is an interesting way of putting it. Eric Brown's
comments are rather different:

"Landing the Mustang required concentration, for at an approach speed of
105 mph the view was bad, and high-rebound ratio landing gear made a
three-point landing tricky, This state of affairs was exacerbated by the
aircraft's lack of directional stability, on the landing run. The U.S.
Navy abandoned the Mustang's deck-landing trials on an aircraft carrier for
these reasons."

It just shows you're taking material out of context. The problems
were because they had made so few modifications for the initial tests.
Had they continued, modified landing gear and modified tail were among
the anticipated changes.

Sure, they could maybe have made the a/c work, about as well as the Seafire
eventually did, and probably considerably less well than the Corsair (and look
how long that took to get right), which had, after all, been designed for the
job.

The view was bad, but certainly no worse than the Corsair. And until
strut changes were made to the Corsair it had the same bouncing
problems.

Uh-huh. and look how long it took to get those fixed (and the slow-speed control
problems, and the stall, etc.). If you haven't already read it, I can recommend
Boone T. Guyton's "Whistling Death: the Test Pilot's story of the F4U Corsair,"
as he was Vought's project pilot for the a/c.

And tests were not abandoned because of poor results. The results were
quite good. They were abandoned because the P-51 did not show any
significant advantage over the naval aircraft it would have replaced.

Sure. Why go to all that trouble to modify the a/c (adding lots of weight),
when you've got the F4U-4 available that has equal or better performance.

All of which makes the later Corsair sound like a great deck-landing a/c by
comparison.

Why should it? The Corsair was notorious for bad visibility during
landing.

Until they raised the seat 7" and bulged the hood, which is why I specified the
'later' Corsairs, i.e. -1A and subsequent. Still not great, but much improved.

But what, exactly, does this digression have to do with the
ability of a P-47 to make a non-catapult take off from a Casablanca or
Bogue class CVE that's only allows roughly half the t/o run, and is 15
knots slower than the Shangri-La?

P-51's were mentioned in the discussion and you posted those
meaningless numbers which had nothing to do with getting a plane off
of a carrier..

I posted the t/o numbers for context, during a discussion of the ability of the
P-47 (and for that matter, most army fighters) to get off a CVE unassisted,
which (barring unusual circumstances), it couldn't. And I'm curious as to why
you think a/c t/o run distances, whether relative or in this case absolute, are
meaningless and have nothing to do with getting a plane off a carrier. Which
numbers do you think would be more relevant?

Guy

Guy Alcala wrote:

Not sure which report you're referring to. It's not in Brown's account which I
quoted. But how long was the deck run, exactly, what were the WoD conditions,
what did the P-51s weigh, and what were they loaded with (and where was the
Cg)? I'd be kind of surprised if the rear tank was filled.

Checking Hardy's "North American Mustang", taking off from the 600
foot mark, the deck run was 250 feet. I don't know which tanks were
filled. The aircraft was at a gross weight of 9600 lbs. The run out
on landing was 82 feet.


Sure, they could maybe have made the a/c work, about as well as the Seafire
eventually did, and probably considerably less well than the Corsair (and look
how long that took to get right), which had, after all, been designed for the
job.

The view was bad, but certainly no worse than the Corsair. And until
strut changes were made to the Corsair it had the same bouncing
problems.

Uh-huh. and look how long it took to get those fixed (and the slow-speed control
problems, and the stall, etc.). If you haven't already read it, I can recommend
Boone T. Guyton's "Whistling Death: the Test Pilot's story of the F4U Corsair,"
as he was Vought's project pilot for the a/c.

I don't think it's a valid argument that because one plane had
teething problems that took a long time to resolve that another
entirely different plane would take as long.


And tests were not abandoned because of poor results. The results were
quite good. They were abandoned because the P-51 did not show any
significant advantage over the naval aircraft it would have replaced.

Sure. Why go to all that trouble to modify the a/c (adding lots of weight),
when you've got the F4U-4 available that has equal or better performance.

In many categories. Which is why they chose not to continue. But you
also have to remember that these tests were conducted in 1944, not
long after the Corsair had been certified for carrier use and before
the first Corsair squadrons went into carrier service in December of
that year. Maybe it didn't seem so unreasonable at the time.

I posted the t/o numbers for context, during a discussion of the ability of the
P-47 (and for that matter, most army fighters) to get off a CVE unassisted,
which (barring unusual circumstances), it couldn't. And I'm curious as to why
you think a/c t/o run distances, whether relative or in this case absolute, are
meaningless and have nothing to do with getting a plane off a carrier. Which
numbers do you think would be more relevant?

Because I don't think the numbers you posted are maximum performance
takeoffs and certainly do not reflect what it takes to get off a
carrier. Note the 250' takeoff distance for these tests as compared
to the standard performance takeoff numbers you quote.



Scott Peterson

--
Ed Knott was shot, and Sam Shott was not.
So, it is better to be Shott, than Knott!
Some say that Knott was not shot, but Shott
says he shot Knott!
Either the shot Shott shot shot Knott, or
the shot Shott shot at Knott was not shot,
or, Knott was not shot! If the shot Shott
shot shot Knott, Knott was shot. But, if
the shot Shott shot shot Shott, then Shott
was shot, not Knott! However, the shot Shott
shot, shot not Shott, but Knott!

80/570

Scott Peterson wrote:

Guy Alcala wrote:

Not sure which report you're referring to. It's not in Brown's account which I
quoted. But how long was the deck run, exactly, what were the WoD conditions,
what did the P-51s weigh, and what were they loaded with (and where was the
Cg)? I'd be kind of surprised if the rear tank was filled.

Checking Hardy's "North American Mustang", taking off from the 600
foot mark, the deck run was 250 feet. I don't know which tanks were
filled. The aircraft was at a gross weight of 9600 lbs. The run out
on landing was 82 feet.

Thanks for that info. I've read the details somewhere a few years back, but can't
remember/find the source. At 9,600 lb. it's clear that the rear tank wasn't filled.
With the aft tank full a clean, fully armed P-51B would be about 9,800 lb., a P-51D
about 10,100 lb. The aft tank holds 85 (US) gallons, or 510 lb. of gas., so that
checks with a P-51D weight above. It's possible that for carrier use the P-51D might
not need the aft tank, as the Hellcat (250 gal.) and Corsair (234-237 gal.) would
have had similar ranges as a P-51 with just the 184 gallons in the wing tanks. OTOH,
endurance might have been inadequate especially when escorting strike a/c, as the
P-51 tended to cruise a lot faster than the navy fighters were designed to. I take
it that 82 feet was the arresting gear pull-out? Either that, or the WoD must have
been really high, if that's braking distance. BTW, you didn't mention the WoD, a
rather critical value. Do you not have that info, or did you just forget?

Sure, they could maybe have made the a/c work, about as well as the Seafire
eventually did, and probably considerably less well than the Corsair (and look
how long that took to get right), which had, after all, been designed for the
job.

The view was bad, but certainly no worse than the Corsair. And until
strut changes were made to the Corsair it had the same bouncing
problems.

Uh-huh. and look how long it took to get those fixed (and the slow-speed control
problems, and the stall, etc.). If you haven't already read it, I can recommend
Boone T. Guyton's "Whistling Death: the Test Pilot's story of the F4U Corsair,"
as he was Vought's project pilot for the a/c.

I don't think it's a valid argument that because one plane had
teething problems that took a long time to resolve that another
entirely different plane would take as long.

Well, let's see. North American was going to have to design a folding wing, beef up
the landing gear and its attachment points, increase the stroke and change the
rebound ratio (it often takes quite a bit of testing to arrive at the proper ratio),
beef up the rest of the structure to absorb repeated cat shots and arrested landings
(just because experienced test pilots can land fairly easily in fairly benign
conditions without bending the a/c, doesn't mean some nugget fresh from the FRS can
do so repeatedly under operational conditions), probably decrease the stall speed by
enlarging the wing (and also to deal with all the extra weight that has been added),
probably modify the ailerons and flaps to improve low speed control and get the stall
speed down to a reasonable level, possibly play around with the throttle box to give
the precise speed adjustments necessary for landing, find the proper location for the
arrestor hook ( a big problem with the Seafire prior to the sting hook on the XV) and
beef up that structure, etc., and then build/modify all the tooling jigs for the new
parts for mass production. Since it's wartime, let's say 1 year minimum, 18-24
months more likely, and that's assuming there are no major problems (and NAA had no
carrier-compatibility design experience).

The Spitfire, which had a far lower stall speed, much lower weight (ca. 7,100 lb. for
a Seafire IIC) and better low speed handling than the P-51, took quite awhile to tame
for carrier use. Indeed, the Seafires' stall speed was lower than either the
Hellcat or Corsair, and it had a shorter t/o run than either owing to its low wing
and power loading. Yet see the poor results at Salerno when operating from escort
carriers, although that was primarily an issue of deck-landing. Quoting from Jeff
Quill's "Spitfi A Test Pilot's Story":

"At this time delivery to the Royal Navy of the American-built Type G-3 [Sic. C-3,
i.e. British versions of the Bogue class]escort carriers (CVEs) was getting started .
.. . . They were, on the whole, very effective ships but their principal shortcoming
was lack of speed; they could not raise more than about 17 knots and in some cases
only 14. This was adequate provided there was at least 10 to 15 knots of natural
surface wind to ensure a 25- to 28-knot wind over the deck which the Seafire liked to
have for landing on. If the wind speed over the deck was below this, serious
problems could arise especially for the less experienced pilots. . . . [skipping to a
discussion of the Seafire in Operation Avalanche]

"D-Day for the assault was 9 September and the first fighter patrols were airborne at
0615. By the end of the day Force V had flown a total of 265 Seafire sorties making
an average of 2.5 sorties for every aircraft embarked. There was no surface wind
throughout the day with the result that there was only 17 knots of wind speed over
the deck for landing; also it was very hot. This lead to a very high incidence of
aircraft damaged in deck landing accidents; by dawn on D plus One the number of
Seafires available in force V had dropped from 105 to 65. As no shore base had been
captured or established on the first day the carriers had to continue to provide the
main fighter cover on the second day, D plus One . . . By dawn on D plus Two the
remaining force of serviceable Seafires was down to 39, but still 160 sorties were
flown during that day. . . . The inescapable conclusion to be drawn from Avalanche
was that the accident rate in landing Seafires on the small escort carriers in
conditions of no surface wind was unacceptably high. A total of 713 sorties had
resulted in 73 deck-landing accidents of which 32 were write-offs, 24 were damaged
beyond immediate repair, and 17 sustained damage to their undercarriage. Throughout
the operations four a/c were lost due to engine failure and a further six from
miscellaneous accidental causes not associated with deck landing. Altogether a total
of 42 Seafires had been written off in accidents and a further 41 damaged ut of a
total embarked force, including those embarked with the covering force [the fleet
carriers], of 121 Seafires."

Realistically, the Seafire XV was the first version that was really carrier-suitable,
and even with them and subsequent versions buckled or wrinkled fuselages weren't all
that uncommon, especially after the Brits went over to American LSO batting
techniques (for commonality), which resulted in a harder landing than British
technique. The Brits made do with the earlier versions because they had to. The
P-51 is probably somewhat stronger structurally to start with than the
Spitfire/Seafire, although still a long way down on strength compared to the products
of the Iron Works. And provided it was only operated from the CVs it would have had
better conditions than the Seafires operating from CVEs had to put up with, but
there's still all that extra weight and higher stall/landing speeds that the P-51
would have to deal with. Stock, the P-51D was still markedly inferior to the Corsair
for carrier compatibility. See, for example:

http://www.geocities.com/slakergmb/id101.htm

and

http://www.geocities.com/slakergmb/id102.htm

for comments about the P-51's stall speed and aileron control at slow speed. This is
a comparison of the P-51B vs. F4U-1 and -1A, and all a/c are somewhat
unrepresentative of stock, but it's still a good source. Be sure to check out

http://www.geocities.com/slakergmb/id3.htm

at the same site, for S.A.C. charts for various Hellcat and Corsair versions, as well
as comparisons between the Hellcat, Corsair and FW-190A-5/U4.


snip

I posted the t/o numbers for context, during a discussion of the ability of the
P-47 (and for that matter, most army fighters) to get off a CVE unassisted,
which (barring unusual circumstances), it couldn't. And I'm curious as to why
you think a/c t/o run distances, whether relative or in this case absolute, are
meaningless and have nothing to do with getting a plane off a carrier. Which
numbers do you think would be more relevant?

Because I don't think the numbers you posted are maximum performance
takeoffs and certainly do not reflect what it takes to get off a
carrier. Note the 250' takeoff distance for these tests as compared
to the standard performance takeoff numbers you quote.

Since we don't have the WoD during the tests or the power settings, the t/o run by
itself is meaningless. Could all of these a/c take off in shorter distances? Sure,
if they had very high WoD, or used War Emergency rather than take off power, but
those aren't things you can do routinely. And, as I mentioned above, the performance
that experienced test pilots can accomplish in lightly loaded, (probably clean and
new) a/c in benign conditions is not indicative of typical operational capability.
I've seen Bob Hoover fly his Commander deadstick through a landing circuit while
doing an 8 (or was it 16) point hesitation roll, land and roll to a stop exactly
where he started engines from without ever touching the brakes, but I don't consider
that reperesentative of what the average pilot can do, routinely or otherwise ;-)

Guy

On Tue, 24 Feb 2004 10:50:38 GMT, Guy Alcala
wrote:



at the same site, for S.A.C. charts for various Hellcat and Corsair versions, as well
as comparisons between the Hellcat, Corsair and FW-190A-5/U4.


Thats an interesting read. One wonders at the possibility of corsairs
providing top cover for daylight bombing raids all the way to Berlin a good
12-18 months before merlin engined mustang was available.


Interesting choice. Build thunderbolts or an equivalent number of corsairs
instead.

greg

--
You do a lot less thundering in the pulpit against the Harlot
after she marches right down the aisle and kicks you in the nuts.

In article ,
Greg Hennessy writes:
On Tue, 24 Feb 2004 10:50:38 GMT, Guy Alcala
wrote:

at the same site, for S.A.C. charts for various Hellcat and Corsair versions, as well
as comparisons between the Hellcat, Corsair and FW-190A-5/U4.


Thats an interesting read. One wonders at the possibility of corsairs
providing top cover for daylight bombing raids all the way to Berlin a good
12-18 months before merlin engined mustang was available.

I dount it - a Mustang's economical cruise burns about 40-45 US
Gal/Hr. An F4U burns about 100 U.S. Gal/Hr.
The Miustang also has its best cruist at 'bout 185 mph IAS. The
Corsair's is 170.

I'm glad that Guy brought up that report, though. It's an intersting
example of how a report can be "cooked". In this case, it happens in
two areas. First is the preparation of teh three aircraft involved.
The P-51C is entirely stock, with a light sanding of the wing. That
cleans it up, some, certainly. The F4U-1A receives a similar prep,
and has the tailhook removed. That also wasn't unreasonable, and was
often dome when the Corsairs were operating exclusively from land
bases. The F4U-1, though, is a different matter entirely. Not only
was the entire surface prepped, but the wing fold joints were filled
and sealed, and the cowling was sealed. Those measures aren't
practical in service. The wing fold seams weren't the worst
offenders, but they did controibute to the drag burden. The real
killer, though, in terms of drag, are the cowling seams. In normal
service condition, those add a serious burden.

The second area, and this is the big one, is the issue of engine
ratings. While the Mustang was held to its handbook limits, both
Corsairs were being operated in excess of their emergency ratings -
slightly so, in the case of the F4U-1A (60" MAP/2700RPM, instead of
57.5" Neutral Aux Stage/59" Low or High Aux / 2700R), and
significantly so in the case of the F4U-1. (65" MAP/2700R).

Nor are the aircraft being compared at the more useful Military Power
rating, which, since the Merlin in the Mustang isn't relying on
Anti-Dtonant Injection, means less of a penalty.

Plotting the performance of the stock (but new) F4U-1D from the SAC
Chart from the same site, (Which uses the same flight test data used
to produce the Pilot's Handbooks), The V1650-3 engined P-51B/C holds
an advantage at all heights. In Military Power (61"/3000R for the
P-51, 53"/2700R for the Corsairs), the P-51 has a significant
advantage at all heights above 'bout 4500'. adn an advantage over the
stock Corsair using Emergency Power above 16.500'. Note that the
reason for the Corsair's better performacne at low altitude in this
case is due to the fact that the external auxiliarry stage
supercharger could be turned off (Neutral Aux) when its extra
compression wasn't needed.

There's one other sneaky trick that is pulled in the presentation of
the report itself. The graph showing the comparative speed
performance is truncated, showing only the true airspeed range between
350 mph amd 480 mph, with the data biased to the left side of the
plot. This does two things. It exaggerates the relatively small
differnces in performance between all 3 airplanes, and puts the
"Juiced-up" Corsair's plot in the center of the plot, where it will
tend to catch the eye. (Right out of "How To Lie With Statistics",
that is.)

Now, even with all that I've said, I don't think that the Corsair was
significantly worse than the Mustang, or vice versa. But this
particular report, which was put together by Navy Pilots, to justify
the development of a Navy Aircraft. (In this case, the F4U-4) If it
had been an Army Air Forces test of the same aircraft types, I'd bet
that the data presented, and the conclusions drawn, would be shaded
just as much the other way.

Interesting choice. Build thunderbolts or an equivalent number of corsairs
instead.

Ah, but P-47s had their own set of advantages/disadvanges. Since they
used turbosuperchargers as their auxiliary stage, rather than a
gear-driven blower, hey had significantly more power as they gained
altitude. (About 350 HP at 21,00o', with that margin increasing up to
the P-47's Critical ALtitude af around 28-30,000'. The P-47 was also
unique among WW 2 fighters in that its controls (Especially roll
control) didn't heavy-up significantly while pulling G. This was a
significant advantage.

I don't think that there were any Corsairs to spare, though. The Navy
had 3 separate manufacturers (Vought, Goodyear, and Brewster) going
flat out to build as many as they, the Brits, and the New Zealanders
could use. (Well, maybo not quite flat out, in the case of Brewster)

--
Pete Stickney
A strong conviction that something must be done is the parent of many
bad measures. -- Daniel Webster

Peter Stickney wrote:

In article ,
Greg Hennessy writes:
On Tue, 24 Feb 2004 10:50:38 GMT, Guy Alcala
wrote:

at the same site, for S.A.C. charts for various Hellcat and Corsair versions, as well
as comparisons between the Hellcat, Corsair and FW-190A-5/U4.


Thats an interesting read. One wonders at the possibility of corsairs
providing top cover for daylight bombing raids all the way to Berlin a good
12-18 months before merlin engined mustang was available.

I dount it - a Mustang's economical cruise burns about 40-45 US
Gal/Hr. An F4U burns about 100 U.S. Gal/Hr.
The Miustang also has its best cruist at 'bout 185 mph IAS. The
Corsair's is 170.

I'm glad that Guy brought up that report, though. It's an intersting
example of how a report can be "cooked".

Yup. ISTR we discussed this in the past..

In this case, it happens in
two areas. First is the preparation of teh three aircraft involved.
The P-51C is entirely stock, with a light sanding of the wing. That
cleans it up, some, certainly. The F4U-1A receives a similar prep,
and has the tailhook removed. That also wasn't unreasonable, and was
often dome when the Corsairs were operating exclusively from land
bases. The F4U-1, though, is a different matter entirely. Not only
was the entire surface prepped, but the wing fold joints were filled
and sealed, and the cowling was sealed. Those measures aren't
practical in service. The wing fold seams weren't the worst
offenders, but they did controibute to the drag burden. The real
killer, though, in terms of drag, are the cowling seams. In normal
service condition, those add a serious burden.

The second area, and this is the big one, is the issue of engine
ratings. While the Mustang was held to its handbook limits, both
Corsairs were being operated in excess of their emergency ratings -
slightly so, in the case of the F4U-1A (60" MAP/2700RPM, instead of
57.5" Neutral Aux Stage/59" Low or High Aux / 2700R), and
significantly so in the case of the F4U-1. (65" MAP/2700R).

Nor are the aircraft being compared at the more useful Military Power
rating, which, since the Merlin in the Mustang isn't relying on
Anti-Dtonant Injection, means less of a penalty.

Plotting the performance of the stock (but new) F4U-1D from the SAC
Chart from the same site, (Which uses the same flight test data used
to produce the Pilot's Handbooks), The V1650-3 engined P-51B/C holds
an advantage at all heights. In Military Power (61"/3000R for the
P-51, 53"/2700R for the Corsairs), the P-51 has a significant
advantage at all heights above 'bout 4500'. adn an advantage over the
stock Corsair using Emergency Power above 16.500'. Note that the
reason for the Corsair's better performacne at low altitude in this
case is due to the fact that the external auxiliarry stage
supercharger could be turned off (Neutral Aux) when its extra
compression wasn't needed.

Of course, it would have been the heavier and slightly draggier P-51D rather than the B/C,
but then again that would have used the -7 engine, fattening up the climb and speed in the
low/mid altitudes where the F4U tended to be superior, while falling off more at the higher
altitudes (where it already held the advantage).

There's one other sneaky trick that is pulled in the presentation of
the report itself. The graph showing the comparative speed
performance is truncated, showing only the true airspeed range between
350 mph amd 480 mph, with the data biased to the left side of the
plot. This does two things. It exaggerates the relatively small
differnces in performance between all 3 airplanes, and puts the
"Juiced-up" Corsair's plot in the center of the plot, where it will
tend to catch the eye. (Right out of "How To Lie With Statistics",
that is.)

Now, even with all that I've said, I don't think that the Corsair was
significantly worse than the Mustang, or vice versa. But this
particular report, which was put together by Navy Pilots, to justify
the development of a Navy Aircraft. (In this case, the F4U-4) If it
had been an Army Air Forces test of the same aircraft types, I'd bet
that the data presented, and the conclusions drawn, would be shaded
just as much the other way.

What? NIH? Surely you jest;-) But I do like the conclusions in the F6F/F4U/FW-190
comparo, especially since Eric Brown, who'd flown all three a/c extensively, was in no
doubt as to which one he considered superior in combat, and it wasn't either of the ones in
dark navy blue;-) And he was a fan of the Hellcat as a naval fighter. Specifically, in
reference to the Corsair II (F4U-1A) head to head vs. an FW-190A-4, he writes:

"This would be a contest between a heavyweight and a lightweight fighter, with virtually
all the advantages on the side of the latter. Having flown both aircraft a lot, I have no
doubt which one I would rather fly. The FW-190 could not be bested by the Corsair."

Which isn't to say that the report is inaccurate as far as it goes, just that there can be
a bit more to it than statistical figures of performance. Handling qualities, personal
preference, flying style and ability are also factors, and besides, the A-5 would have been
a bit long in the tooth by the time the F4U-1D was in service -- the A-8 would be more
contemporary, or even the D-9. The Corsair would be one of the few a/c that could roll
with an FW-190, though.

Interesting choice. Build thunderbolts or an equivalent number of corsairs
instead.

Ah, but P-47s had their own set of advantages/disadvanges. Since they
used turbosuperchargers as their auxiliary stage, rather than a
gear-driven blower, hey had significantly more power as they gained
altitude. (About 350 HP at 21,00o', with that margin increasing up to
the P-47's Critical ALtitude af around 28-30,000'. The P-47 was also
unique among WW 2 fighters in that its controls (Especially roll
control) didn't heavy-up significantly while pulling G. This was a
significant advantage.

And besides, even the razorback P-47s had 305 gallons internal fuel (the bubble-canopy D-25
and subsequent had 370), while the F4U-1/-1A had 361, but only 237 of that was in
self-sealing tanks. The other 124 gallons were in unprotected tanks in the outer wings.
There was also an inerting system for at least some of the internal tanks (IIRC it was
CO2), but I don't remember if it extended to the wing tanks or not. But those tanks were
removed from the -1D and subsequent models, presumably to reduce vulnerability, leaving the
internal fuel (with the same basic engine, although different supercharging) considerably
less than the P-47 had. The F4U did have larger drop tanks available earlier, though.
IIRR, it was around Big Week or a bit later that the P-47s first got the "150" gallon
(actual capacity 165 gallon) drop tanks.

Guy

Guy Alcala wrote:
Peter Stickney wrote:

In article ,
Greg Hennessy writes:
On Tue, 24 Feb 2004 10:50:38 GMT, Guy Alcala
wrote:

at the same site, for S.A.C. charts for
various Hellcat and Corsair versions, as well
as comparisons between the Hellcat, Corsair
and FW-190A-5/U4.


Thats an interesting read. One wonders at
the possibility of corsairs
providing top cover for daylight bombing
raids all the way to Berlin a good
12-18 months before merlin engined mustang
was available.

I dount it - a Mustang's economical cruise
burns about 40-45 US
Gal/Hr. An F4U burns about 100 U.S. Gal/Hr.
The Miustang also has its best cruist at 'bout
185 mph IAS. The
Corsair's is 170.

I'm glad that Guy brought up that report,
though. It's an intersting
example of how a report can be "cooked".

Yup. ISTR we discussed this in the past..

In this case, it happens in
two areas. First is the preparation of teh
three aircraft involved.
The P-51C is entirely stock, with a light
sanding of the wing. That
cleans it up, some, certainly. The F4U-1A
receives a similar prep,
and has the tailhook removed. That also wasn't
unreasonable, and was
often dome when the Corsairs were operating
exclusively from land
bases. The F4U-1, though, is a different
matter entirely. Not only
was the entire surface prepped, but the wing
fold joints were filled
and sealed, and the cowling was sealed. Those
measures aren't
practical in service. The wing fold seams
weren't the worst
offenders, but they did controibute to the
drag burden. The real
killer, though, in terms of drag, are the
cowling seams. In normal
service condition, those add a serious burden.

The second area, and this is the big one,
is the issue of engine
ratings. While the Mustang was held to its
handbook limits, both
Corsairs were being operated in excess of
their emergency ratings -
slightly so, in the case of the F4U-1A (60"
MAP/2700RPM, instead of
57.5" Neutral Aux Stage/59" Low or High Aux
/ 2700R), and
significantly so in the case of the F4U-1.
(65" MAP/2700R).

Nor are the aircraft being compared at the
more useful Military Power
rating, which, since the Merlin in the Mustang
isn't relying on
Anti-Dtonant Injection, means less of a penalty.

Plotting the performance of the stock (but
new) F4U-1D from the SAC
Chart from the same site, (Which uses the
same flight test data used
to produce the Pilot's Handbooks), The V1650-3
engined P-51B/C holds
an advantage at all heights. In Military
Power (61"/3000R for the
P-51, 53"/2700R for the Corsairs), the P-51
has a significant
advantage at all heights above 'bout 4500'.
adn an advantage over the
stock Corsair using Emergency Power above
16.500'. Note that the
reason for the Corsair's better performacne
at low altitude in this
case is due to the fact that the external
auxiliarry stage
supercharger could be turned off (Neutral
Aux) when its extra
compression wasn't needed.

Of course, it would have been the heavier and
slightly draggier P-51D rather than the B/C,
but then again that would have used the -7 engine,
fattening up the climb and speed in the
low/mid altitudes where the F4U tended to be
superior, while falling off more at the higher
altitudes (where it already held the advantage).

There's one other sneaky trick that is pulled
in the presentation of
the report itself. The graph showing the
comparative speed
performance is truncated, showing only the
true airspeed range between
350 mph amd 480 mph, with the data biased
to the left side of the
plot. This does two things. It exaggerates
the relatively small
differnces in performance between all 3 airplanes,
and puts the
"Juiced-up" Corsair's plot in the center of
the plot, where it will
tend to catch the eye. (Right out of "How
To Lie With Statistics",
that is.)

Now, even with all that I've said, I don't
think that the Corsair was
significantly worse than the Mustang, or vice
versa. But this
particular report, which was put together
by Navy Pilots, to justify
the development of a Navy Aircraft. (In this
case, the F4U-4) If it
had been an Army Air Forces test of the same
aircraft types, I'd bet
that the data presented, and the conclusions
drawn, would be shaded
just as much the other way.

What? NIH? Surely you jest;-) But I do like
the conclusions in the F6F/F4U/FW-190
comparo, especially since Eric Brown, who'd
flown all three a/c extensively, was in no
doubt as to which one he considered superior
in combat, and it wasn't either of the ones
in
dark navy blue;-) And he was a fan of the Hellcat
as a naval fighter. Specifically, in
reference to the Corsair II (F4U-1A) head to
head vs. an FW-190A-4, he writes:

"This would be a contest between a heavyweight
and a lightweight fighter, with virtually
all the advantages on the side of the latter.
Having flown both aircraft a lot, I have no
doubt which one I would rather fly. The FW-190
could not be bested by the Corsair."

Which isn't to say that the report is inaccurate
as far as it goes, just that there can be
a bit more to it than statistical figures of
performance. Handling qualities, personal
preference, flying style and ability are also
factors, and besides, the A-5 would have been
a bit long in the tooth by the time the F4U-1D
was in service -- the A-8 would be more
contemporary, or even the D-9. The Corsair
would be one of the few a/c that could roll
with an FW-190, though.

Interesting choice. Build thunderbolts or
an equivalent number of corsairs
instead.

Ah, but P-47s had their own set of advantages/disadvanges.
Since they
used turbosuperchargers as their auxiliary
stage, rather than a
gear-driven blower, hey had significantly
more power as they gained
altitude. (About 350 HP at 21,00o', with that
margin increasing up to
the P-47's Critical ALtitude af around 28-30,000'.
The P-47 was also
unique among WW 2 fighters in that its controls
(Especially roll
control) didn't heavy-up significantly while
pulling G. This was a
significant advantage.

And besides, even the razorback P-47s had 305
gallons internal fuel (the bubble-canopy D-25
and subsequent had 370), while the F4U-1/-1A
had 361, but only 237 of that was in
self-sealing tanks. The other 124 gallons were
in unprotected tanks in the outer wings.
There was also an inerting system for at least
some of the internal tanks (IIRC it was
CO2), but I don't remember if it extended to
the wing tanks or not. But those tanks were
removed from the -1D and subsequent models,
presumably to reduce vulnerability, leaving
the
internal fuel (with the same basic engine, although
different supercharging) considerably
less than the P-47 had. The F4U did have larger
drop tanks available earlier, though.
IIRR, it was around Big Week or a bit later
that the P-47s first got the "150" gallon
(actual capacity 165 gallon) drop tanks.

Guy

So how would the F4U fared over Europe against the Me-109 and Fw-190? Assuming
there were no encounters between Royal Navy Corsairs (or Hellcats) and Luftwaffe
fighters in Norway. (Although there had to be some?)

Posted via www.My-Newsgroups.com - web to news gateway for usenet access!

"Greg Hennessy" wrote in message
...

Thats an interesting read. One wonders at the possibility of corsairs
providing top cover for daylight bombing raids all the way to Berlin a
good 12-18 months before merlin engined mustang was available.


Not possible, for several reasons.

There were no combat-ready Corsairs 18 months before the Merlin Mustang.
The Merlin Mustang entered combat in December 1943, 12-18 months prior to
that would be the period June to December 1942. The first F4U-1s were
delivered to VMF-124 in September 1942, and that unit was declared
combat-ready three months later.

The F4U-1 could not reach Berlin from England.

There were no US bombing raids on Berlin 12-18 months before Merlin engined
Mustang was available, the first USAAF strike on Berlin was in March 1944.



Interesting choice. Build thunderbolts or an equivalent number of corsairs
instead.


The only real advantage the Mustang had over the Thunderbolt was range. If
the Thunderbolt had been able to reach Berlin in 1943 the USAAF wouldn't
have gone to the Merlin Mustang as an escort fighter.

"Steven P. McNicoll" wrote:

"Greg Hennessy" wrote in message
...

Thats an interesting read. One wonders at the possibility of corsairs
providing top cover for daylight bombing raids all the way to Berlin a
good 12-18 months before merlin engined mustang was available.


Not possible, for several reasons.

There were no combat-ready Corsairs 18 months before the Merlin Mustang.
The Merlin Mustang entered combat in December 1943, 12-18 months prior to
that would be the period June to December 1942. The first F4U-1s were
delivered to VMF-124 in September 1942, and that unit was declared
combat-ready three months later.

And first saw combat on Feb. 14th, 1943.

The F4U-1 could not reach Berlin from England.

Well, it could, but didn't have enough internal fuel for the normal allowance
for combat and the return. The P-47D-25 and subsequent, with 370 gallons
internal and a pair of 150 gal. drop tanks, could just escort to Berlin and back
with a combat allowance given an experienced group and direct routing, but by
the time enough bubble-canopy Jugs were available to re-equip an entire group
the 8th AF transition to P-51s was well along, and the P-51s still had better
range and endurance. The P-47s were more comfortable, though. The radius king
was the P-47N (556 gallons internal), but that barely made it into the war in
the Pacific.

Guy

of the Iron Works. And provided it was only operated from the CVs it would have had
better conditions than the Seafires operating from CVEs had to put up with, but
there's still all that extra weight and higher stall/landing speeds that the P-51
would have to deal with. Stock, the P-51D was still markedly inferior to the Corsair
for carrier compatibility. See, for example:

http://www.geocities.com/slakergmb/id101.htm

Guy

In addition to the specialized requirements for operation from a
carrier deck, the US navy would have put some weight on the practical
advantages of standardizing on a proven radial engine, such as the
R-2800, which was also used by the other naval types, including the
Hellcat and Avenger. This would have simplified requirements for
maintainance and spares, not a small consideration on an aircraft
carrier. The radial engines also had the advantage of being less
vulnerable to combat damage, a consideration that might receive some
extra emphasis for over water operation. Furthermore, there were
promising prospects for further performance improvements with the C
series R-2800s and R-4360.

Given that operational requirements for naval operations would have
emphasized performance at low and medium altitudes, particularly for
the Pacific theatre, the Mustang's fine high altitude performance
would have been relatively unimportant.

Robert