P-61 or Reverse Lend Lease Mosquito

IIRC, the unit the operated the P-61 in the Pacific had a Staff Sargent will one aerial credit. I would guess he was the radio/ radar operator who operated the turret!

pinehilljoe said:

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I have always loved the Airacuda. It looks like a plane straight out of Sky Captain and The World of Tomorrow,

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Sky Captain's P-40 was pretty cool, too!



Didn't mean to stray off the topic...but it WAS a good movie

Now to be fair or put things in perspective the US had already built the XB-15


149 ft wingspan and 2780 sq ft of wing area and they were working on the XB-19

212 ft wing span (over twice the Lancaster) and 4392 sq ft of wing area means that they were also working on something to shoot them down. Assuming that if they could a bomber that size a potential enemy could also.

GregP said:

The worst criticism of the Mosquito is also still valid today. It hs the highest Vmc of any twin in WWII. As long as both fans were turning and you accelerated past Vmc, you were OK. If you lost an engine before that, it was going to land straight ahead or crash with finality. Steve Hinton said when he flew the Mosquito that came out of New Zealand that it had a higher Vmc than the crusie speed of many plane he had flown. Once it was comfortably fast, thingfs were dandy.

By way of example, in a Mosquito FB6, safety speed (Vmc) at 17,000 pounds, +9" boosty, and flaps up or 15° down was 155 knots. At +18 lbs boost it was 170 knots! The manul sattes these spees vary considerably between aircraft! So, they could be higher!

That ain't good for a plane operating from a short island strip.

By contrast, Vmc for a P38J/L was 120 mph (104 knots). You can see it would be an unusual flight experience for a US pilot. Can't find Vmc for a P-61 right now, but the stall speeds are lower than for a P-38.

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Is the Vmc related to the stall speed?

Shortround6 said:

Now to be fair or put things in perspective the US had already built the XB-15


149 ft wingspan and 2780 sq ft of wing area and they were working on the XB-19

212 ft wing span (over twice the Lancaster) and 4392 sq ft of wing area means that they were also working on something to shoot them down. Assuming that if they could a bomber that size a potential enemy could also.

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They had the manning squared away in the XB-15 squadron...

Cheers,
Biff

GrauGeist said:

The learning curve for turret fighters was being learned while the P-61 was already in development - the solution for the turret on the P-61 was to be remote and more aerodynamic, still was found to be troublesome when it was put into service, so in some cases it was removed and the well was used for additional fuel storage.

Even though the U.S. didn't make any turret fighters, they still came up with fighter ideas that were not all that great.

View attachment 352722

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Here's a shot of the cockpit...

Flash Gordon could fly anything (even a turret fighter!)

The closer the engines are together, the closer to Vmc will be to stall and vice versa. Vmc is ALSO related to both the fin and rudder area as well as the rudder angle limit stops.

The P-38 had a rudder directly behind each engine in the propeller airflow. The Mosquito had a single fin not in the propeller airflow, so it had little yaw control by rudder until at least medium airspeed had been attained, probably at least 60 knots to generate some tail torque effect with rudder deflection. I haven't looked up that number ... just a SWAG. My thought is that had de Havilland put a twin fin Mosquito together, the effect on top speed would have been slight, but the effect on Vmc would have been dramatic.

Of course, I have no proof of same since they didn't build one of those puppies, and do not have the time or interest to try the calculations myself. I'd have to drag out an aerodynamics text anyway.

I have heard more than once that this was a primary reason for less than sharp US interest on the Mosquito, but have never seen it listed in any official documents, so it is hearsay at best.

For USAAF night fighter crews in Italy the P61 must have been welcome as their old Bristol Beaufighters were having trouble catching modern Luftwaffe bombers unladen in stern chases. They had been asking for RAF Mosquitos to be released to them.

I've been working on this story for over 45 years - now it's time I should got to stop everything else and write it all down.

The P-61 was a massive failure as a night fighter. The Mosquito was superior in every way but one - it wasn't available when the AAF most needed it.

The great night fighter fly-off was rigged, but not by the British pilot. Knowing that the P-61 lost any advantage above 20,000 feet, the test was run at 5,000 feet, 10,000 feet, 15,000 feet, and 20,000 feet. The two aircraft flew toward each other in daylight, then tried to get on each other's tail. The P-61, while slow, altitude limited, and restricted in range, was a terrific dog-fighter -- of course, night fighting made nearly no use of dogfighting abilities. The American crews got to keep their aircraft, their esprit d'corps, and their bragging rights, but they lost out on a superior aircraft.

The Mosquito's single-engine capabilities were known, but not fatal -- in the MTO, the single AAF Ju 188 kill involved a chase across most of Italy, over the Apennines, into Austria. The entire chase was flown with the dead right engine windmilling.

Cheers,



Dana

Hi Dana, and welcome to the forum!

Dana Bell said:

...The P-61 was a massive failure as a night fighter...

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I am curious about this.

In what context can the P-61 be called a "massive failure"?

Glider said:

How comes someone nearly always wants to blame the UK for every daft idea the USA came up with!!!

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All the "daftness" in the Black Widow came straight from Northrop, the most unconventional a/c builder in the US. Can't lay that one on the Brits! "Daft" or not, an awesome machine none the less. Apparently there was a west coast P-61 instructor pilot who would repeatedly take on four plane flights of ponies, bolts, cats, or Corsairs in daytime close-in dogfights and score "kills" on all four while remaining untagged. Thanks to that turret and asymmetric thrust.

The P-61 was not a massive failure. It did well, in all theaters of operation. You could make a case for the Mosquito, perhaps a decent one, but the P-61 was a good night fighter that could turn with most much lighter aircraft. It could EASILY out-turn the Mosquito, and only later models of the Mosquito were faster.

The Mosquito used for the test was an MF Mk XVII and it was about as fast as a P-61A. The Mosquito NF 30 was faster. but didn't fly until March 1944. We didn't need the Mosquito in place of the P-61. We could have used some Mosquitos, true, but would probably have assigned them to duties other than P-61 duties.

Hi Folks,

I didn't touch on the turrets, but I'm afraid this one actually did come from the Brits. Before the US entered the war, Ira Eaker visited the UK to report on the RAF's latest technical advances. I interviewed him in 1977, have his pre-war report - the RAF convinced him that the ultimate future night fighter would carry a remote control turret, and that information was passed on to Northrop. The big problem was the radar-guided, automatic gun-laying system being designed for the P-61 - it never worked. In the ultimate irony, the AAF's final report on the P-61s problems noted (on the first page) that the turret helped the aircraft overcome its many disadvantages, but recommended (on page 3) that the turret be removed to add fuel.

Arnold and Spaatz had planned to replace all P-61s in Europe and the MTO with Mosquitos in May/June 1944 - we wanted the Mk.30s, but production problems meant we couldn't have any until November - long after they weren't needed over the invasion beachheads.

The P-61 was, in test pilot Vance Breeze's words, an "old man's airplane" - easy to fly, safe to land in the dark, and very forgiving. It was wonderfully maneuverable, had a great rate of climb, and was heavily armed. But it was too slow, it couldn't fly high enough to reach German and Japanese night bombers, and it's missions were of limited duration - generally around two hours. My opinion doesn't matter on this -- the theater commanders and Arnold himself were desperate for a replacement even before the first combat missions.

Highly motivated, well trained crews made the aircraft do amazing things - but its roles were of limited range, altitude, and speed. When the 422nd went out with the Brits on a target-rich evening, they were generally the only unit to return without a kill. (The Brits had a way of saying, "Not to worry, you'll do better next time" that clearly meant the Yanks weren't up to snuff -- both sides knew it, and the Americans were pretty well torched off about.) In the Pacific, P-61 pilots were met with jeers and cat calls when they left the evening movies to try to intercept high-flying Japanese night raiders. After repeated failures, the Black Widows on Middleburg were replaced by Hellcat night fighters - much to the relief of the folks on the ground, who were being bombed nightly.

The one 416th NFS Mosquito kill was the second interception of that Ju 188 that night - a P-61 nearly made the interception, but had to return to base due to lack of fuel.

I would describe a failure as an aircraft incapable of performing the assigned mission. The mission involved the downing of high-flying, high-speed night raiders, and the P-61 couldn't do it. The crews were told they had the best available aircraft - they weren't told the Mosquito wasn't available. They believed in the Black Widow - but higher command understood the aircraft's limitations and would have happily replaced it - not the definition of a success.

Cheers,



Dana

Wonder why the P-61 wasn't designed with 2-stage superchargers or turbochargers.

GregP said:

The Mosquito used for the test was an MF Mk XVII and it was about as fast as a P-61A. The Mosquito MF 30 was faster. but didn't fly until March 1944. We didn't need the Mosquito in palce of the P-61. We could have used some Mosquitos, true, but would probably have assigned them to duties other than P-61 duties.

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The Mosquito NF XXX began operations in July 1944, in limited numbers. About the same time that the P-61 began operations for the 8th AF.

gjs238 said:

Wonder why the P-61 wasn't designed with 2-stage superchargers or turbochargers.

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They had 2 stage superchargers - the P-61A had same engine as used in the F6F, and the P-61B used a similar model.

The problem may have been that the P-61 was as heavy empty as a Mosquito B.XVI with cookie on board and full of fuel (but not drop tanks).

gjs238 said:

Wonder why the P-61 wasn't designed with 2-stage superchargers or turbochargers.

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wuzak said:

They had 2 stage superchargers - the P-61A had same engine as used in the F6F, and the P-61B used a similar model.
....

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Inded, Hellcat, P-61A and P-61B used the came engine, 2-stage supercharged R-2800-10:

In hindsight, if the P-61 was so successful, (or if the brass at the time had so much faith in the aircraft) why this?