Which is the better fighter, P-40F or Typhoon?

[pbehn]

Dive speed, unless under full control is academic. The Spitfire achieved the highest recorded speed, but under very controlled conditions to prevent it being another "lawn dart" statistic, and then it lost a prop. Under normal combat circumstances the Spitfire would be out performed in dive by the P-47 with the Spitfire catching it just before they hit the ground, if the dive continued.

 

[Greyman]

I decided to get a bit deeper into the Typhoon's aileron characteristics and I'm starting to think the RAE and NACA graph (link) I've been using---and looking no further--may not be giving the full picture for one reason or another re: the Typhoon.

In reverse chronological order:


A&AEE, Typhoon Ib Brief Handling Trials, 6 Feb 1944
Results of tests

The aircraft was dived to 480 mph A.S.I. when trimmed for all-out level flight. ... Acceleration tended to build up to some extent but no violent tendencies were present and control column forces were light.​

Army Air Forces Materiel Command, Memorandum Report on Typhoon I, 6 Dec 1943 (link)
Handling & Control at Various Speeds

All control forces are reasonable up to about 450 I.A.S. where the ailerons become heavy. ...​

Maneuverability and Aerobatics

In general, handling during maneuvers and in aerobatics is very good. Radius of turn is short, and the airplane rolls well although the aileron forces are heavy. ...​

Conclusions

The Typhoon has proved to be a very useful fighter-bomber. Good high speed and maneuverability at low altitudes coupled with sufficient fire power and exceptional load carrying ability make it a formidable weapon.​

A&AEE, Typhoon Ib Handling Trials, 10 Mar 1943
Controls

Although the controls become heavier with increase of speed, particularly the rudder, they are moderately light and effective throughout the speed range.​

AFDU, FW.190 Trials vs. 4-cannon Typhoon, 9 Aug 1942
Dive

The controls of the Typhoon, although good in a dive, are not so light and responsive as those of the FW.190.​

Air Fighting Development Unit, Tactical Trials – Typhoon I Aircraft, 30 Oct 1941
Flying Characteristics

The controls are well-balanced and comparatively light, and at speeds above 400 m.p.h., I.A.S., there is little tendency to "heavy-up" ...​

Conclusions

The aircraft is comparatively light on controls, especially at high speeds.​

A&AEE, Typhoon P.5212 Fuel Consumption, handling and Diving Trials, 18 Dec 1940
Behavior in the dive

The controls generally are very effective up to the maximum A.S.I. and remain moderately light.​

Conclusions

In the dive the handling qualities are excellent ...​

A&AEE, Typhoon P.5212 Interim Report on Performance and Handling Trials, 29 Oct 1940
Diving

All controls were used at 475 I.A.S. The ailerons are moderately light and sufficiently effective up to this speed ...​

Conclusions and Recommendations

The controls are light and well harmonized throughout the very wide speed range and show signs of careful and painstaking development.​

Perhaps when low stick forces are used the Typhoon feels fine, but when higher forces are used it loses effectiveness. The NACA noted this when testing the Spitfire and Hurricane. At 5lb stick force the British fighters were far better than the P-36 and P-40, but when lateral forces reached 30-lb the US fighters were clearly superior.

For what it's worth, British tests on the P-40:


A&AEE, Kittyhawk I Handling Trials, 3 Dec 1942
Controls

The ailerons are light and quick in response at all speeds up to maximum level speed. ... The control becomes heavier with increase of speed, but is not excessively so at maximum level speed. At speeds over 400 m.p.h. A.S.I. the control heaviness increases rapidly, the ailerons becoming almost immovable at 460 m.p.h. A.S.I., the limiting diving speed.​

A&AEE, Kittyhawk II Brief Handling Trials, 3 Mar 1943
Dives

The aircraft was trimmed for all-out level flight and dived to 450 m.p.h. A.S.I. at both loadings. In both cases it tended to yaw to the right and above about 400 m.p.h. A.S.I. the force required on the rudder pedal to hold the aircraft straight became excessive and some retrimming necessary.​

The push force on the control column during the dive was moderately heavy for the normal loading. ... The aircraft was steady in the dives.​

Recovery was normal on releasing the push force, no excessive accelerations resulting.​

 

[pbehn]

I don't know if the use changes the judgement, in 1940 were cannons (or any weapons) fitted, by 1943 it is appraised as a fighter bomber I believe.

 

[wuzak]

Dive speed, unless under full control is academic. The Spitfire achieved the highest recorded speed, but under very controlled conditions to prevent it being another "lawn dart" statistic, and then it lost a prop. Under normal combat circumstances the Spitfire would be out performed in dive by the P-47 with the Spitfire catching it just before they hit the ground, if the dive continued.

I always thought that acceleration in the dive was more important than maximum dive speed. At least in combat situations.

 

[wuzak]

And the response in this specific comparison between two aircraft (the result of a challenge from another thread) is a series of diversions to explain why P-40F pilots made so many more victory claims than the Typhoon, (and seemed to like their aircraft better), each easily debunked.

• They made a lot more P-40s (but not of this version - only 2000 P-40F/L vs 3000 Typhoons)
• The P-40 faced weak opposition consisting of Bombers and obsolete Japanese planes (not true - and most of the victories by P-40Fs were against fighters, and mostly Bf 109s)
• But Macchi 202s were second rate! (Not true either, or certainly an outlier position)
• The Typhoon didn't fight for as long so had fewer opportunities (P-40 F/L were in combat from roughly August 1942 to Sept 1944, but 90% of their victory claims were before Sept 43.)
• The P-40 fought in multiple Theaters (but not this version - 17 out of 18 squadrons using the plane were in the Med)
• The Typhoon shot down Fw 190s and the P-40 couldn't (P-40's clearly did)

• 3,000 Typhoons were built between 1941 and 1945. 2,000 P-40Fs and Ls were built in around a year, possibly less, about 1942. The P-40Fs and Ls were available in greater numbers earlier. Some Typhoon squadrons only started using them in late 1943, and a couple I've looked up only operated them for a short while before converting to Lancasters!
• There may be some confusion as to which P-40 is being spoken about.
• I don't know enough about Macchi 202s. The comments I have read in here seem to indicate they were lightly armed, which would certainly make it more difficult for them to shoot down P-40s.
• The Typhoon started its career, possibly too early, chasing down hit and run raiders. That was in 1942 (maybe late 1941). Home defence remained priority until 1943. By late 1943 the Typhoon was largely relegated to fighter-bomber duties. Certainly countering the raiders was important, but these weren't massed attacks - usually a handful of aircraft, often just the one. The Med was a more active theatre than England was in 1942/43. And the German fighter efforts were concentrated in the Russian front, mostly, and the Med at that time, but starting to build up in the west in the latter half of 1943 as the 8th AF threat increased.
• The Typhoon only fought in the ETO.
• No-one said that the P-40 couldn't shoot down Fw 190s, but they couldn't have chased them down the way Typhoons did against low level raiders. P-40Fs could not have chased down V-1s either, but Typhoons could.

 

[pbehn]

I always thought that acceleration in the dive was more important than maximum dive speed. At least in combat situations.

That's what I said, maximum dive speed is (or was) an academic execise, look at the starting altitude, the angle of dive and the pull out. The Spitfire was never considered to be a good performer in dive situations.

 

[GrauGeist]

I don't know enough about Macchi 202s. The comments I have read in here seem to indicate they were lightly armed, which would certainly make it more difficult for them to shoot down P-40s.

The MC.202 was a fast, agile fighter, but it was indeed lightly armed.
It's armament consisted of two 12.7mm MGs in the cowling and two 7.7mm MGs in the wings (one per side).

 

[Schweik]

3,000 Typhoons were built between 1941 and 1945. 2,000 P-40Fs and Ls were built in around a year, possibly less, about 1942. The P-40Fs and Ls were available in greater numbers earlier. Some Typhoon squadrons only started using them in late 1943, and a couple I've looked up only operated them for a short while before converting to Lancasters!

Of the 5 US fighter groups flying the P-40F /L, the Group whose stats I posted upthread, the 325 "Checkertails", scored all of their 133 claimed victories with the P-40 between May 1943 and October 1943. That is five months. The similarly successful 57th FG scored all 144 of their claims between August 1942 and January 1944. None of these groups flew P-40s for more than two years.

There may be some confusion as to which P-40 is being spoken about.

Maybe by some people? But I pointed it out in the Thread title and about 4 times since, as everybody keeps using the excuse of vastly more P-40s built. This thread is a comparison of the Merlin powered P-40F and L vs. the Typhoon. Not all P-40s.

I don't know enough about Macchi 202s. The comments I have read in here seem to indicate they were lightly armed, which would certainly make it more difficult for them to shoot down P-40s.

Well, I know this is yet another silly debate about WW2 fighters, but some of the best had a relatively small number of guns. Without really getting into the larger issue, the German contemporary of the MC 202 which fought along side it was the Bf 109 F-2, which had 1 x 15mm cannon in the spinner and 2 x 7.92 machine guns on the nose, firing through the prop, and the Bf 109 F-4 which had a single 20mm cannon in the spinner and the two light machine guns on the nose. I think their armament was pretty close to equivalent.

The Typhoon started its career, possibly too early, ... By late 1943 the Typhoon was largely relegated to fighter-bomber duties.... The Med was a more active theatre than England was in 1942/43. And the German fighter efforts were concentrated in the Russian front, mostly, and the Med at that time,

Well I think the truth is the Germans were mostly focused on the Russian Front in general, the kind of neglected the Med too. But regardless, the P-40 was also supposedly relegated to fighter bomber duties in the same period. The Typhoon, albeit troubled in it's early years, was deployed from 1941 to 1945, whereas the P-40F was deployed from 1942 - 1944 and I believe in smaller numbers. Parts of that period had a lot of air to air combat, but long stretches did not. As you noted, activity picked up quite a bit in 1943 and 1944 in the English Channel. So I think it equals out.

The Typhoon only fought in the ETO.

Yes. And my point was - the P-40F / L only fought in the MTO (barring one squadron)

No-one said that the P-40 couldn't shoot down Fw 190s, but they couldn't have chased them down the way Typhoons did against low level raiders. P-40Fs could not have chased down V-1s either, but Typhoons could.

Well, they did chase them down as low level raiders over Sicily, Anzio etc. But I grant you P-40s could not have caught V-1s or Me 262s.

 

[michael rauls]

This is an interesting comparison of two planes I have never seen compaired before which makes sense as they were used mostly in different theaters and were on the same side.
I would say that the Typhoon certainly looks better on paper. However, when one takes into account stability issues with the Typhoon( not even sure what these were just read vague references to " stability issues" sometimes in articles but that sounds ominous) and the fumes in the cockpit thing apparently never being sorted out I'm not so sure.
This may be a case of qualities that dont show up in performance stats that are good or maybe not so good.
I have read the p 40 was quite fast down low compaired to most other ww2aircraft.
For example I have read that below 5000 feet it was slightly faster than a p51d and about the same up to 10,000. Is this true?
Although if the Typhoon was doing 400 mph + at low altitude that is truly scorching
along. Dont think the p40, or much else for that matter, was close to that at low altitude.

 

[Shortround6]

[QUOTE="michael rauls, post: 1448050, member: 69991
I have read the p 40 was quite fast down low compaired to most other ww2aircraft.
For example I have read that below 5000 feet it was slightly faster than a p51d and about the same up to 10,000. Is this true?[/QUOTE]

only in a P-40s Fanboy's head.

A P-51D could do 365mph at sea level using Military power. (61in MAP)
The Australians got a P-40N up to 315mph at sea level using WEP (57in of MAP)
The best anybody has claimed for P-40N was 378mph at 10500ft using 57in of Map. please note that the throttle is fully open, there is no more boost to be had at this altitude.
A P-51D could 360mph at 10,000ft on cruising power (2700rpm and 46in) and 400mph at 3000rpm and 61in. The P-51 was allowed 67in at WEP.

Although if the Typhoon was doing 400 mph + at low altitude that is truly scorching
along. Dont think the p40, or much else for that matter, was close to that at low altitude.

Typhoons were good for anywhere between 340 mph and the low 360s depending on allowable boost (it was changed at least once) and drag reduction measures taken.

340mph at sea level was pretty darn good in late 1941 and early 1942.

360mph in 1944???

 

[Schweik]

As Shortround noted (dude you need to fix your quote tags) P-51 was very fast down low. The Allison Engned P-51A / Mustang I was getting close to 400 mph at pretty low altitude. A maxed out overboosting P-40K might be close at sea level, but probably still a bit slower. Generally the P-51 would be faster at all altitudes due to their excellent streamlining, quasi laminar flow wings and the jet effect of their exhaust.

The reason a lot of pilots in the CBI for example preferred the P-40 was A) because the cooling systems being up front in the nose, they were considered less vulnerable to groundfire (which tended to hit further back on the body of the aircraft), and B) the P-40 was a lot more maneuverable than the P-51 down low, so it helped deal with Japanese fighters (even though the normal strategy was to 'boom and zoom', sometimes it helped a lot to do a quick turn or two). That is why P-40 units had more victory claims and better survival ratios in that Theater than P-51 units.

 

[Kevin J]

This is an interesting comparison of two planes I have never seen compaired before which makes sense as they were used mostly in different theaters and were on the same side.
I would say that the Typhoon certainly looks better on paper. However, when one takes into account stability issues with the Typhoon( not even sure what these were just read vague references to " stability issues" sometimes in articles but that sounds ominous) and the fumes in the cockpit thing apparently never being sorted out I'm not so sure.
This may be a case of qualities that dont show up in performance stats that are good or maybe not so good.
I have read the p 40 was quite fast down low compaired to most other ww2aircraft.
For example I have read that below 5000 feet it was slightly faster than a p51d and about the same up to 10,000. Is this true?
Although if the Typhoon was doing 400 mph + at low altitude that is truly scorching
along. Dont think the p40, or much else for that matter, was close to that at low altitude.

I think you'll find it was the Mustang I/Ia with over boost that was faster than a P-51B/C/D/K below 5000 feet and about the same up to 10,000 which is why the RAF were still using them for fighter recce right up to the end of the war. If you want to carry 8 60 lb rockets then its a Typhoon for me, just think of the speed loss that would occur on a P-40 which is at least 30 mph slower at all heights. If I wanted a low/medium altitude interceptor then I would choose a P-40K in 1942 using over boost, one powered by a single stage low rated Merlin engine in 1943, and one powered by a two stage Merlin that could operate on 150 grade fuel from 1944. http://www.wwiiaircraftperformance.org/Aircraft_Engines_of_the_World_Rolls-Royce_Merlin.pdf

 

[MIflyer]

Best book I have found about the Typhoon and Tempest in combat is "Tempest Pilot" by Sdrn Leader CJ Sheddan DFC RNZAF.

Among other things, he describes his experience in landing a Typhoon in the channel. It's poor ditching characteristics were a result of the wing shape, rather than the big airscoop. The Tempest, with the same engine and airscoop, ditched just fine.

Another very good book with pilot experiences relative to the Whirlwind, Typhoon, and Tempest is "Flying Under Fire" about Canadian pilots in WWII.

 

[GrauGeist]

The reason a lot of pilots in the CBI for example preferred the P-40 was A) because the cooling systems being up front in the nose, they were considered less vulnerable to groundfire (which tended to hit further back on the body of the aircraft), and B) the P-40 was a lot more maneuverable than the P-51 down low, so it helped deal with Japanese fighters (even though the normal strategy was to 'boom and zoom', sometimes it helped a lot to do a quick turn or two). That is why P-40 units had more victory claims and better survival ratios in that Theater than P-51 units.

The reason the P-40 had more victories in the CBI, is because it was there first (late 1941 onward) and in greater numbers.
The P-51 didn't reach the CBI until 1944 and they were the C/D/K and CA-17 variants.

Chennault also expressed concern over the P-40's vulnerability because it was water-cooled...

 

[Elmas]

Too many people seems to rely too much on numbers.
As a structural engineer I have nothing to say about numbers but ...
When it was necessary to bring the Macchi MC.200 prototype from Varese to Guidonia for flight experiments, the distance was far greater than the autonomy of the aircraft and therefore an intermediate refuel was arranged.
At the intermediate refueling airport, no trace of the precious MC.200 prototype, so frantic rescue expeditions were immediately organized.
A short time later the MC200 showed up directly at Guidonia Airport, where it landed regularly.
The Pilot, Cap. Adriano Mantelli, had found a powerful jet stream.
Needless to say, Capt. Mantelli received a severe reprimand for this...

 

[Shortround6]

There were some P-51As used in the CBI theater but the quantities were low. Probably no more than 1-3 squadrons at any one time. On dec 31st 1943 it was listed that 60 P-51As total were serving in the CBI and North African Theaters.
Likewise there were two P-38 squadrons (one in India and ome in Burma?) and we can argue all week about survival rates and such but it just may be that the P-38 and Allison P-51s were being used in such small numbers as to make drawing valid conclusions from statistics rather difficult.
I mean if you only have 12 planes operational for a mission and you lose 2 you have lost 16.6%.
If you have 36 planes on a mission and lose 4 you have 11% losses.
Nobody can say if you had more of the rarer planes if they would have lost more on the same mission.

 

[Schweik]

Generally, in WW2, you have two kinds of successful fighter designs: Low wing-loading fighters good at turning but relatively slow ("Turn and Burn" fighters), and high wingloading fighters not so good at turning, but relatively fast ("Boom and Zoom" fighters) . Over time, for the faster planes, it also helped to have a good rate of climb and / or dive, (a high mach number helped a lot) and a very good roll rate seemed to be very important.

But both methods worked. The game for the low wing loading fighters was to wait for the right situation and pounce, the longer the fight lasted the better. The game for the high wing loading fighters was to hit and run. Both methods had their Tactical and Operational advantages,

So for example in terms of aircraft active in combat in the Spanish Civil War and Manchuria, you had:

1936-1939

Low wing loading / Slow
Ki-27
Cr -32
I-15
He 51
Hawker Fury

High wing loading / Fast
I-16
Me 109D
He - 100
Fiat G.50

Later in the Battle of France, Battle of Britain, conquest of Poland, continued fighting in China and the Pacific, the Winter War, early fighting in the Middle East and the Battle of Greece, you have newer faster monoplane fighters really coming into their own.

1940-1941

Low wing loading / Slow ("TnB")
Hurricane
P-36 / Hawk - 75
D.520
Ki-43
A6M
LaGG-3
I-153
Cr 42
Gladiator
Pzl P-11

High wing loading / Fast ("BnZ")
Bf 109E and later F
Bf 110
Ki-45
MC 200
I-16

The Spitfire really stands out here because it was fast at ~ 360 mph, but also had a very low wing loading. So it's kind of both. And that is why it was so good.

By 1942 - the key turning point year of the war, things are moving very fast indeed. Biplanes are now almost exclusively relegated to Close Air Support or point defense (and suffering heavy losses). In the beginning of the year the Allies are losing badly and barely hanging on. By the end of the year they have rallied and are winning key victories on all fronts.

1942

Low wing loading / Slow (TnB)
A6M
Ki 43
Hurricane II
P-40
F4F
La - 5
Yak -1
LaGG -3
I-16
MC. 200

High wing loading / Fast (Bnz)
Bf 109 F4 and G
MC 202
Ki-61
Fw 190
MiG- 3
Typhoon
P-38F
P-51A (Allison Engined)

The Spitfire is once again in the middle, being fast while having low wing loading, but the Spitfire Mk V is slipping back toward the 'Turn and Burn' role, being a bit slower than the newer Bf 109s and outclassed in terms of performance by the appearance of the Fw 190. The newer Spit IX and VIII are fast enough to comfortably straddle both roles.

Through the war, speed and performance were a moving bar that fighter designs had to keep up with, there was a certain minimum below which a fighter just wasn't viable because it couldn't catch bombers, couldn't catch enemy fighters and couldn't refuse combat or disengage at will. So for example in 1940 the MC 200 and the Bf 110 were fairly successful in the "boom and zoom" role, but by 1941 they were already reaching their design limits due mainly to speed. Boom and Zoom fighters in particular have to be faster than the low wing loading fighters they are competing with because they will lose in a turn fight. However wing loading also tends to creep up over time, so fighters that had decent turning capability but were originally designed for the "Boom and Zoom" role sometimes found a second life (or death) in the "Turn and Burn" niche. So for example the I-16 and MC 200, both hit and run fighters against biplanes earlier in their career, have become "Turn and Burn" fighters by 1942 against their faster and more modern opponents (Bf 109 and P-40 respectively). Other like the MiG-3, Ki-45 and Bf-110 either got phased out or made into fighter bombers or night fighters.

The best fighters- the ones with the longest most successful careers, brought something extra to the table. The Spitfire is the standout in the early years of the war becuase of it's almost unique combination of very high speed and very low wing loading. The Bf 109 also stands out because though it's clearly a higher wing loading, BnZ fighter, it is still pretty agile, and also has very good altitude performance. The A6M combines very low wing loading with an excellent climb rate and especially the ability to climb at a steep angle, enabling it to for example do a loop and come down behind a pursuing aircraft. The early P-38, for all it's faults brought good high altitude performance and was fast enough in the Pacific that it could disengage from just about any Japanese fighter in a high speed climb.

The advantage the P-40 had was that it was pretty good at a lot of things. Though it was basically a "Turn and Burn" fighter in Russia and the Med, being slower but more maneuverable than the Bf 109 and Fw 190, but speed was just at the bottom end of the "Fast" family, maybe more in the middle down low, and it was substantially faster than most of the fighters in the Pacific and CBI and could therefore act more like a "Boom and Zoom" fighter there. In both Theaters the combination of excellent roll rate, good high speed handling and very fast dive speed meant that P-40 pilots were able to disengage from combat when they needed to (albeit, with some risk to their engines) and that is why it remained in front line fighter service long after many of it's near contemporaries like the Hurricane had been taken out of the front line.

The major flaw of course was the altitude limitation. It wasn't the only fighter to have that issue - A6Ms did to some extent as well, almost all the Soviet fighters did, the P-51A of course, and so on. But that kept it out of the big-bomber war in 1943-1945 and that is what most people concentrate on in WW2 aviation history. Other fighters also had significant flaws of course - the Spitfire and Bf 109 series always had short range, as did most of the Soviet fighters. The early to mid-war Spitfires had the flooding carburator. The 109 series had notoriously tight controls at higher speeds. The early to midwar Japanaese fighters had no armor or effective self sealing fuel tanks. The P-38 had a host of issues notably compressability limiting diving capability which was a major problem in the BnZ role. But flaws could be offset by good training and tactics. When training and pilot quality were very high, as was generally the case for the Axis early in the war, they could offset the flaws of their planes. When training and pilot quality declined, they no longer could as well, accelerating their death spiral.

 

[Schweik]

The reason the P-40 had more victories in the CBI, is because it was there first (late 1941 onward) and in greater numbers.
The P-51 didn't reach the CBI until 1944 and they were the C/D/K and CA-17 variants.

Lets try to keep in mind - the Merlin type P-51 B / D etc. arrived quite late in most Theaters, but it still racked up a high victory ratio anyway. For example (merlin engined) Mustang units didn't get to the Med until later in 1944, but claimed 1053 in the Med, compared to 592 for (American) P-40s and 263 for P-47s. Arriving late generally meant that the Axis pilots weren't as experienced. And there was till air to air combat going on regularly in the CBI and Pacific to the end of the war.

Chennault also expressed concern over the P-40's vulnerability because it was water-cooled...

That is true - a radial engined fighter is generally much less vulnerable to ground fire or to a 'golden BB' taking them out. This was heavily emphasized by Japanese pilots according to their own records and memoirs. However available Allied fighters didn't seem to perform that well against Japanese fighters down low where most (though definitely not all) of the combat was in that Theater. The best candidate would have probably been the Hellcat but they didn't send any to that Theater.

The P-40 also apparently had some armor added to the radiator at some point though the precise details remain mysterious.

 

[Clayton Magnet]

Bf 109 F-4 which had a single 20mm cannon in the spinner and the two light machine guns on the nose. I think their armament was pretty close to equivalent.

the MG 151/20 was a fearsome weapon, and certainly superior to 2 synchronized Breda-SAFAT machine guns

But that kept it out of the big-bomber war in 1943-1945 and that is what most people concentrate on in WW2 aviation history

...and that is what most people Americans concentrate on...

 

[MIflyer]

I recall reading that a P-51 pilot who was shot down in Korea saying that he preferred the P-40 to the P-15 for ground attack. His reasoning was that with ground attack missions the aircraft tend to get hit in the aft section and that is where the P-51's radiator was. The P-40 was liquid cooled but the radiator was up front and was less like to get damaged.

Note that in the CBI the Hawk 75 Mohawk with the R-1820 engine was considered to be adequate until it was replaced by the Hurricane in 1943, which was considered to be adequate well into 1944 and was not fully replaced by the P-47 until almost the end of the war.

One Hurricane pilot said that after the Japanese took the big losses in the Pacific battles that there was a huge drop off in enemy air activity in the CBI.