P-61 Without Turret

[wuzak]

The Mosquito was already in pipeline when the turret idea surfaced.

As a recon bird...

No, as a light bomber.

The prototype W4050 was, nominally, a bomber.

The second prototype, W4051, was the PR prototype.

W4052 was the fighter prototype - long range day fighter, not night fighter.

W4053 was the turret fighter prototype - still not a night fighter.

[tomo pauk]

I thought it was better for the following reasons

Aerodynamically-efficient engine-mounting: The P-38 for example, had an inline engine, turbochargers, the intake for the engine, the oil-coolers and radiators for the engine; I was under the impression that two huge engine-nacelles to mount that stuff with a single fuselage would have more drag than a twin-boomed aircraft with a small gondola in between.

The Hornet have had all of that, but not turboes, that were anyway above the wing of the P-38. The long winded cooling system of the P-38 also drove the weight up. For a turboed aircraft in 'classic' layout, see McDonnel Moonbat.

A location to mount the landing-gear: The ability to flip the gear back into the booms avoid having to fold them into the wings, which in turns allows more fuel to be carried in the wings; the P-38 carries fuel in the booms.

Most of the 2-engind aircraft were featuring the U/C legs retracting in the nacelle, so twin booms don't add any advantage here.
The P-38 carried all of it's fuel in the wings plus the drop tanks. The 'classic' layout makes it far easier to have fuel in the fuselage, while the P-38 did not carry any fuel in the pod; not that it could not be done after a redesign.

Improved aerodynamic of efficiency of the wing and tail area in between the booms as they'd produce an endplate effect, plus you'd only need one elevator.

In order to judge this, we'd need a serious aerodynamic study. Historically, we know that other 'classic' twins, like the Whirlwind, Fw-187, Hornet or Tigercat have had favorable maneuverability and payload capabilities.
Twin boom, on the other hand, adds the surplus weight away from centreline, thus having the adwerse effect on the roll rate. Having the extra fuel outwards from the fuselage also messes with roll rate.
One big or two smaller elevators is a moot point IMO.

[tomo pauk]

Just to comment on the side by side, vs tandem seating debate, it must be remembered that the early radar scopes required a very dark compartment, or a viewing hood, to see the scope.  Side by side makes for a wider, draggier fuselage, and draggier canopy.  No way a F7 Tigercat could be side by side without a completely new fuselage. The F7 is really, really, skinny.   

I think having the radar operator in tandem, or even within another part of the fuselage, worked fine. Both arrangements have pros and cons.     

Much of the tandem crew layout advantages on the P-61 were negated by the pod being so wide, please see upper part of the http://zenoswarbirdvideos.com/Images/P-61/P-61anglesarmor.gif.
The gun belly didn't do much for streamlining either.

[PR19_Kit]

five US aircraft producers were approached with USAF request to produce the (then recon) Mosquito under license. All five rejected the offer, so let's give the USAF some credit here.

I think that the 5 companies were idiotic to do this...

'Not invented here Rules OK', especially amongst the US defence community........

[gral_rj]

It may even be simpler than that, the companies might have decided setting up a production line for a wooden plane(which would have required different skills from the working force as well as different tooling) not worth the bother. I don't doubt NIH played a role, but I'd say setting up costs would be more important to the companies.

[tomo pauk]

The mostly-wooden aircraft does not compete with metal aircraft for the work force, so the US company producing the mostly-wooden aircraft culd tap on the work force and tools/machines previously not used for the needs of war aircraft production. Setting up the facility to produce the military aircraft in the time od major war would mean the opportunity for earning the money.

I'd second on that NIH played a major role here.

[sandiego89]

To chime in on the "not invented here" thought, we must remember that many US companies were quite happy to build other designs under licence- Martin B-29's, Lockheed and Douglas B-17's, Goodyear Corsairs, etc etc.  Yes I realize these are US designs, but some of these companies were bitter rivals, but they took the opportunity when presentented.  This may be taken as some evidence that they were willing to produce other designs when they had the capacity, know how, and the profit looked right.    I agree with gral_rj that buiness descisions were perhaps part of the mix.  When a Mosquito was pitched for US prodcution perhaps few aviation companies had the know how and workforce to build a high performance, complex wooden airframe, for the the anticipated profit.  Finally perhaps they saw the end of wood and fabric and preferred to invest in production lines better sutied for metal airframes and growth.    

[dogsbody]

de Havilland Canada produced 1,134 Mosquitos.

https://en.wikipedia.org/wiki/De_Havilland_Canada



Chris

[wuzak]

To chime in on the "not invented here" thought, we must remember that many US companies were quite happy to build other designs under licence- Martin B-29's, Lockheed and Douglas B-17's, Goodyear Corsairs, etc etc.  Yes I realize these are US designs, but some of these companies were bitter rivals, but they took the opportunity when presentented.  This may be taken as some evidence that they were willing to produce other designs when they had the capacity, know how, and the profit looked right.    I agree with gral_rj that buiness descisions were perhaps part of the mix.  When a Mosquito was pitched for US prodcution perhaps few aviation companies had the know how and workforce to build a high performance, complex wooden airframe, for the the anticipated profit.  Finally perhaps they saw the end of wood and fabric and preferred to invest in production lines better sutied for metal airframes and growth.    

Slightly different scenarios. The US manufacturers named built the aircraft to US government order often in factories built and/or furnished by government investment. Not building whatthe government wants might have led to building nothing at all.

In the case of the Mosquito there was no order, just have a look and tell us what you think.

Beech, IIRC, was one of the five manufacturers asked to look at producing the Mosquito, but were particularly scathing about the wooden construction.

[PR19_Kit]

Beech, IIRC, was one of the five manufacturers asked to look at producing the Mosquito, but were particularly scathing about the wooden construction.

Like I said, Not Invented Here.............

[Rheged]

Beech, IIRC, was one of the five manufacturers asked to look at producing the Mosquito, but were particularly scathing about the wooden construction.

Like I said, Not Invented Here.............

Whereas, I sometimes wonder, do our revered political masters work the other way round.  "Invented here" seems to make them blench, cancel things, and buy from someone else.   (BITING SARCASM MODE DISENGAGE)

[PR19_Kit]

Beech, IIRC, was one of the five manufacturers asked to look at producing the Mosquito, but were particularly scathing about the wooden construction.

Like I said, Not Invented Here.............

Whereas, I sometimes wonder, do our revered political masters work the other way round.  "Invented here" seems to make them blench, cancel things, and buy from someone else.   (BITING SARCASM MODE DISENGAGE)

It certainly seems so, recent events going some way to prove that.

[KJ_Lesnick]

wuzak

No, as a light bomber.

The prototype W4050 was, nominally, a bomber.

The second prototype, W4051, was the PR prototype.

W4052 was the fighter prototype - long range day fighter, not night fighter.

W4053 was the turret fighter prototype - still not a night fighter.

In the context I was responding, I thought he was talking about the US making overtures to buy one: General Arnold wanted them as a reconnaissance bird, not as a bomber (we didn't really have a dedicated reconnaissance aircraft).  Admittedly, when one considers that the USAAF did fit one with a Norden sight, that might very well have changed had the manufacturers General Arnold requested built it.

As I understand it

• The primary role of the plane was a bomber: The reconnaissance capability was a logical development as it was fast and high flying
  
• Whether correct or not, I do remember reading of him proposing putting a tail-gun in the aircraft to placate the guys at the Air Ministry (he mostly wanted to keep the program alive)
  
• The fighter development was largely to keep the program alive
  
• I didn't know a turret-fighter was developed for day use, but the turret fighter was a popular idea among the brits and was eventually the basis for the night-fighter concept
  

.

Slightly different scenarios. The US manufacturers named built the aircraft to US government order often in factories built and/or furnished by government investment. Not building whatthe government wants might have led to building nothing at all.

Are we talking about the P-61 or the Mosquito?

In the case of the Mosquito there was no order, just have a look and tell us what you think.

Beech, IIRC, was one of the five manufacturers asked to look at producing the Mosquito, but were particularly scathing about the wooden construction.

Hap Arnold did have considerable political ties: Had he not been so erratic (the guy was a moody angry fuzzy bunny who had some mad-scientist qualities as well, such as the idea of dropping watches and booby-traps to kill Germans who captured them, and use the War Weary Bomber project as an American V-1), he could have probably used his connections to impose his will on the companies for an American Mosquito.


tomo pauk

The Hornet have had all of that, but not turboes

That greatly helped keep the size of the nacelle down -- while it's possible to make a compact turbo, in those days it seemed somewhat art as well as science.  The use of intercoolers that were always air-cooled seemed to be a problem too (I know it was the lighter option, but volume is important in planes too and the best analogy I got is to compare a 1.5 pound brick to a 1 pound bag of cotton).

that were anyway above the wing of the P-38.

Would it have been better if it was below?

The long winded cooling system of the P-38 also drove the weight up.

It also took up the inboard wing which could have otherwise carried a butt-load of fuel (which it did in the P-38J)

For a turboed aircraft in 'classic' layout, see McDonnel Moonbat.

I didn't know it used a turbo, but they did succeed in being more compact!  Consider that design flew in 1943 not 1939...

Most of the 2-engind aircraft were featuring the U/C legs retracting in the nacelle, so twin booms don't add any advantage here.

I didn't know that!

The P-38 carried all of it's fuel in the wings plus the drop tanks.

Actually the booms carried some fuel, but otherwise you're correct: The fuel was in the outboard wing initially, and after the early P-38J's in the inboard and outboard wings.

In order to judge this, we'd need a serious aerodynamic study. Historically, we know that other 'classic' twins, like the Whirlwind, Fw-187, Hornet or Tigercat have had favorable maneuverability and payload capabilities.

True

Twin boom, on the other hand, adds the surplus weight away from centreline, thus having the adwerse effect on the roll rate. Having the extra fuel outwards from the fuselage also messes with roll rate.

The P-38's roll rate was decent at low to medium speed, at higher speeds it was due to increased control-loads.

Much of the tandem crew layout advantages on the P-61 were negated by the pod being so wide, please see upper part of the http://zenoswarbirdvideos.com/Images/P-61/P-61anglesarmor.gif.

The pod is quite wide, and maybe thinning it would be a good idea.  However, one must also factor in fineness ratio, and the pod was very long and the radar dish was going to inevitably be a certain amount.

The gun belly didn't do much for streamlining either.

I'm not sure what effect it did, but it did have all the guns on the centerline made it easier to aim...


PR19_Kit

'Not invented here Rules OK', especially amongst the US defence community........

I personally do understand the position that it is preferable to have weapons built indigenously not under license.  There's a number of very good logical reasons

• It's important to make sure that there is an adequate number of people who work in the defense field: If you don't, you will end up being dependent on other nations for weapons
  
• Nations do not have friends: They have interests
  
• If one nation is responsible for supplying the defense needs of a multitude of smaller nations: It's defense industry becomes excessively large.  Iindustries work in their own interests; when they become powerful enough: They become able to game the system to suit their own needs, which leads to more wars and conflicts.  Look at the war in Iraq, for example (it was totally unnecessary, it was based on deception and lies; it was fought on the basis of oil, military contractors, and to a degree: High finance, after all they fund everything).
  
  

.
That being said, in times of war it's sometimes acceptable to bend the rules a little bit for the greater good.  Remember

• There would be no P-51's despite NAA developing such a magnificent design: It was only due to the British Purchasing Commission demanding large numbers of P-40's and happening to come across NAA's interesting proposal...
  
• We developed large numbers of Mk.XIV bombsights, which were not used by the USAAF or USN (far as I know) to be used on RAF bombers, which used them to devastating effect
  
• We developed a significant percentages of the Rolls Royce Merlins which were used in huge numbers on a number of fighters and at least three bombers I can think of offhand (Mosquito, Lancaster, Lincoln)
  
• The British developed the cavity magnetron which we used on night-fighters such as the P-61, and variants of the F4U, F6F, F7F, and P-38 variants
  
• The British Tube-Alloys project was instrumental to our nuclear-bomb program
  
• The British also provided us with blueprints to develop the Mosquito should we have chose to (we didn't); knowledge of early jet-engines; knowledge of how to build the Tallboys and Grand-Slams
  
• They also provided us integral data for supersonic flight (which we swiped from them), much to their later regret.
  

.

Rheged

Whereas, I sometimes wonder, do our revered political masters work the other way round.  "Invented here" seems to make them blench, cancel things, and buy from someone else.

If you mean in Europe, that's probably got to do with the E.U.

[tomo pauk]

That greatly helped keep the size of the nacelle down -- while it's possible to make a compact turbo, in those days it seemed somewhat art as well as science.  The use of intercoolers that were always air-cooled seemed to be a problem too (I know it was the lighter option, but volume is important in planes too and the best analogy I got is to compare a 1.5 pound brick to a 1 pound bag of cotton).

You might check out the size & weight of the B series turbos and see that weight was ~150 lbs, with diameter comparable with the diameter of the prop spinner, or the main wheel. The turbo will not push the width of nacelle up, it might push up the length, though.

Would it have been better if it was below?

'Above the wing' meaning 'it did not needed boom to house it'.

It also took up the inboard wing which could have otherwise carried a butt-load of fuel (which it did in the P-38J)

The wing inboard the engines always carried most of the fuel in the P-38. The outboard fuel tanks were added from P-38J on, 2 x 55 US gals. Compare that with fuel in fuselage carried by many S/E fighters, not just US produced, where, if/when needed, 200-370 gals were carried in the fuselage only.

I didn't know it used a turbo, but they did succeed in being more compact!  Consider that design flew in 1943 not 1939...

Let's not use the date as excuse. That location of turbo wasn't a result of any great invention or scientific/technological breakhrough.

Actually the booms carried some fuel, but otherwise you're correct: The fuel was in the outboard wing initially, and after the early P-38J's in the inboard and outboard wings.

I'm afraid you got this competetly wrong. There was no fuel tanks in the boom, plus what the P-38J brough re. fuel tanks. Please see the manuals for the P-38, that are available at least at avialogs.com,  ww2aircraft.net and at Zeno's warbirds site.

The P-38's roll rate was decent at low to medium speed, at higher speeds it was due to increased control-loads.

Nope - the roll rate was low on high speeds, a bit better at medium speeds and again low on high speeds. Introduction of the hydraulicaly operated ailerons improved rate of roll, most notably at high speeds.

The pod is quite wide, and maybe thinning it would be a good idea.  However, one must also factor in fineness ratio, and the pod was very long and the radar dish was going to inevitably be a certain amount.
[The gun belly didn't do much for streamlining either.]
I'm not sure what effect it did, but it did have all the guns on the centerline made it easier to aim...

The cannons can be installed higher, while still clearing the radar dish; or the wing roots, like at Tigercat, or at the side of the pod (like in Fw twins or Meteor), thus making cancelling plenty of the shortcoming of a 'thick' pod. Still makes a concentrated firepower.

[wuzak]

wuzak

No, as a light bomber.

The prototype W4050 was, nominally, a bomber.

The second prototype, W4051, was the PR prototype.

W4052 was the fighter prototype - long range day fighter, not night fighter.

W4053 was the turret fighter prototype - still not a night fighter.

In the context I was responding, I thought he was talking about the US making overtures to buy one: General Arnold wanted them as a reconnaissance bird, not as a bomber (we didn't really have a dedicated reconnaissance aircraft).  Admittedly, when one considers that the USAAF did fit one with a Norden sight, that might very well have changed had the manufacturers General Arnold requested built it.

As I understand it

• The primary role of the plane was a bomber: The reconnaissance capability was a logical development as it was fast and high flying
  
• Whether correct or not, I do remember reading of him proposing putting a tail-gun in the aircraft to placate the guys at the Air Ministry (he mostly wanted to keep the program alive)
  
• The fighter development was largely to keep the program alive
  
• I didn't know a turret-fighter was developed for day use, but the turret fighter was a popular idea among the brits and was eventually the basis for the night-fighter concept
  

I'm not sure who you mean by "him".

You are correct, though - a fixed rearward firing gun was proposed for the bomber and PR variants of the Mosquito, but not implemented in production.

A PR version was quickly adapted from the bomber as basically all that was needed was camera mountings and ports.

If anything it was the PR role that "saved" the Mosquito program.

The fighter prototype W4052 flew before the PR prototype W4051 only because the fuselage of W4050 was damaged and was replaced by that of W4051. W4051 then received the fir production fuselage, of what would have been the first PR.I.

The first 50 aircraft ordered contained a mix of PR, bomber and fighter versions, the numbers of which changed several times.

The turret day fighter had been an idea of teh RAF for some time. As evidenced by the Boulton Paul Defiant.

As for the night fighter concept, the Blenheim IF and IVFs had turrets, but it was based on the Blenheim I and IV respectively, which were light bombers with turrets. Similarly for the Defiant, soem of which were converted to night fighters.

Not the case for the Mosquito and Beaufighter NFs.

It was for the P-61, but whether that came from the RAF or USAAF I do not know.

Slightly different scenarios. The US manufacturers named built the aircraft to US government order often in factories built and/or furnished by government investment. Not building whatthe government wants might have led to building nothing at all.

Are we talking about the P-61 or the Mosquito?

I was talking of American firms building designs from other American firms during WW2 - such as Martin building B-29s.

Hap Arnold did have considerable political ties: Had he not been so erratic (the guy was a moody angry fuzzy bunny who had some mad-scientist qualities as well, such as the idea of dropping watches and booby-traps to kill Germans who captured them, and use the War Weary Bomber project as an American V-1), he could have probably used his connections to impose his will on the companies for an American Mosquito.

Remember that the Mosquito proposal was before US entered the war.

For a turboed aircraft in 'classic' layout, see McDonnel Moonbat.

I didn't know it used a turbo, but they did succeed in being more compact!  Consider that design flew in 1943 not 1939...

The XP-67's turbo was probably no closer to the engine than the P-38's.

The XP-67's main landing gear, which was sizeable, retracted into a space between the engine and the turbo.

The main difference with the X-67's turbo was its orientation - the turbo was mounted with its shaft roughly parallel with the direction of flight, so that both the turbo and wastegate exhausts were pointing rearwards and contributed some thrust.

http://www.warbirdsresourcegroup.org/URG/images/xp67-7.jpg

Most of the 2-engind aircraft were featuring the U/C legs retracting in the nacelle, so twin booms don't add any advantage here.

I didn't know that!

Have you ever looked at a photograph or cutaway drawing of twin engined aircraft of WW2?

'Not invented here Rules OK', especially amongst the US defence community........

That being said, in times of war it's sometimes acceptable to bend the rules a little bit for the greater good.  Remember

• There would be no P-51's despite NAA developing such a magnificent design: It was only due to the British Purchasing Commission demanding large numbers of P-40's and happening to come across NAA's interesting proposal...
  
• We developed large numbers of Mk.XIV bombsights, which were not used by the USAAF or USN (far as I know) to be used on RAF bombers, which used them to devastating effect
  
• We developed a significant percentages of the Rolls Royce Merlins which were used in huge numbers on a number of fighters and at least three bombers I can think of offhand (Mosquito, Lancaster, Lincoln)
  
• The British developed the cavity magnetron which we used on night-fighters such as the P-61, and variants of the F4U, F6F, F7F, and P-38 variants
  
• The British Tube-Alloys project was instrumental to our nuclear-bomb program
  
• The British also provided us with blueprints to develop the Mosquito should we have chose to (we didn't); knowledge of early jet-engines; knowledge of how to build the Tallboys and Grand-Slams
  

[/quote]

MkXIV bomb sights were built under licence, not developed, in the US.
Merlins were built under licence by Packard. This was to expand the supply of Merlins for Britain, though the initial contract of 9,000 specified 1/3 of production would go to the USAAF. Packard did do some parallel development to Rolls-Royce.
The Cavity Magnetron and radar designs were given to the US to develop as British priority at the time (1940) was in developing and producing weapons to defend against German attack. It, and teh plans for the Whittle Jet, was a bribe, in effect, to get access to the vast US industrial capacity for building weapons.