P-61 Without Turret

[KJ_Lesnick]

tomo pauk

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.

I was talking about the size of the inter-coolers...

The turbo will not push the width of nacelle up, it might push up the length, though.

That's right but the excess length of the nacelle probably does make it easy to arrive at the idea of just making it into a boom.

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

Width wise no

The wing inboard the engines always carried most of the fuel in the P-38.

I thought the inboards had the intercoolers and the outboards had the fuel?

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

True enough, but the nacelles were quite long, though some of the length had to do with the exhaust flow path

Nope - the roll rate was low on high speeds, a bit better at medium speeds and again low on high speeds.

So at low speeds it was the result of the high aspect ratio?

The cannons can be installed higher, while still clearing the radar dish; or the wing roots, like at Tigercat

The F7F-N's had 12.7mm in the fuselage; switch to 4 x 20mm cannon it might fit but your ammo will be low.


wuzak

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

Well in one case I was referring to tomo pauk; in the other case De Havilland himself.

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.

I didn't know the PR version had one actually...

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.

It was used in that role first

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

Yeah... it worked if the enemy thought it was a Hurricane, but otherwise it was slower and enemies just attacked from below

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.

The bombers were converted I guess because they were big and could easily accommodate the radar; the turret-fighter was used probably because it had a two-man crew; in both the guns were used like a turret-fighter...

Not the case for the Mosquito and Beaufighter NFs.

I thought the NF version was to have a turret initially, but it was removed because people at DH had their heads screwed on right...

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

It's not explicitly said in the Joe Baugher site, in Wikipedia it says the BPC demanded multi-turrets...

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

So, the government would have been less likely to accept factory space to build large numbers of P-61's if they proposed an alternate design as well as the normal submission?

While on this, I'm curious about something: Why modern day don't we have several aircraft manufacturers building each other's planes under license?

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

I guess after 12/7/41 the idea left his mind?

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.

Kind of like a jet a bit... is there any place one could find a diagram of the nacelle layout?

[wuzak]

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.

I didn't know the PR version had one actually...

It didn't. It was only proposed.

I thought the NF version was to have a turret initially, but it was removed because people at DH had their heads screwed on right...

No. It was never intended to have a turret.

The first NF was the NF.II - developed from the F.II which did not have a turret.

is there any place one could find a diagram of the nacelle layout?

Try Google.

[KJ_Lesnick]

wuzak

It didn't. It was only proposed.

Okay

No. It was never intended to have a turret.

These versions seem to be proposed around the same time as the P-61: I'm curious why they made us build a turret-fighter when they weren't going to use it on the DH98

Try Google.

I've already been doing that...

[wuzak]

No. It was never intended to have a turret.

These versions seem to be proposed around the same time as the P-61: I'm curious why they made us build a turret-fighter when they weren't going to use it on the DH98

"They" (the RAF) did not make "you" (the USAAC) do anything.

The initial specifications were drawn up by a USAAC board - the Emmons Board.

The saga of the Northrop P-61 Black Widow begins back in August 1940, at the height of the Blitz on London. During this time, the US air officer in London, Lt. Gen. Delos C. Emmons, underwent a briefing in which he was brought up to date on British progress on radar (Radio Detecting and Ranging).

At the same time, the British Purchasing Commission that was shopping for aircraft in the USA announced that they urgently required a night fighter that would be capable of stopping the German bombers that were attacking London by night. Such a fighter would have to be able to stay on station above London all night, which meant at least an 8-hour loiter time. In addition, the night fighter needed to have sufficient combat altitude in order to take on the bombers when they showed up.

When General Emmons returned to the USA, he reported that the British had an urgent need for night fighter aircraft, and that American industry might be able to supply that need. A preliminary specification was drawn up by the Emmons Board and was passed on to Air Technical Service Command at Wright Field in late 1940. Because of the heavy weight of the early AI radar and because of the high loiter time required, a twin-engined aircraft was envisaged.

http://www.joebaugher.com/usaf_fighters/p61_1.html


Though this says that Northrop were developing an aircraft to British specifications before the USAAC requirements were issued, both specifying turret armament.

[tomo pauk]

I was talking about the size of the inter-coolers...

Size of P-38's intercoolers have had nothing to do with the P-38 being twin boom aircraft.

That's right but the excess length of the nacelle probably does make it easy to arrive at the idea of just making it into a boom.

I'm not sure that nacelle was that long.

I thought the inboards had the intercoolers and the outboards had the fuel?

I know that.

So at low speeds it was the result of the high aspect ratio?

Probably that, plus the excess weight away from centreline.

[The cannons can be installed higher, while still clearing the radar dish; or the wing roots, like at Tigercat]
The F7F-N's had 12.7mm in the fuselage; switch to 4 x 20mm cannon it might fit but your ammo will be low.

The F7F-any-type have had 4 cannons in wing roots, that will do it either for the Tigercat or the 'P-61 light'.

[wuzak]

I thought the inboards had the intercoolers and the outboards had the fuel?

I know that.

The intercoolers were in the outer wing panels and the fuel in the inner wing sections.

http://www.enginehistory.org/Allison/V-1710Details/allisonv1710installationinp38.html

[kitnut617]

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.

I didn't know the PR version had one actually...

It didn't. It was only proposed.

I thought the NF version was to have a turret initially, but it was removed because people at DH had their heads screwed on right...

No. It was never intended to have a turret.

The first NF was the NF.II - developed from the F.II which did not have a turret.

is there any place one could find a diagram of the nacelle layout?

Try Google.

You two need to get the Sharp/Bowyer book on the Mosquito, there was no ""NF Mk.II"", and there was no intension of having a turret in the Mosquito.  The Air Ministry got into the 'we must have turrets' way of thinking and instructed De Havilland to investigate a turret option.  After some trials it was quickly abandoned ----  just the same when the Air Ministry instructed De Havilland to use Merlin Power Eggs over the leading edge radiators (like Lancaster engine nacelles). De Havilland was having none of it and refused on both accounts.

[PR19_Kit]

You two need to get the Sharp/Bowyer book on the Mosquito, there was no ""NF Mk.II"",

Erm, surely there was?

The radar equipped fighters, with the early AI Mk IV radar, 4 x 20 mm cannon and 4 x .303 MGs were designated NF MK II according to many references I have.

[kitnut617]

You two need to get the Sharp/Bowyer book on the Mosquito, there was no ""NF Mk.II"",

Erm, surely there was?

The radar equipped fighters, with the early AI Mk IV radar, 4 x 20 mm cannon and 4 x .303 MGs were designated NF MK II according to many references I have.

In the list of variants of the Mosquito (Appendice No.4, page 393), it just has F Mk.II, and then says, day and night long-range fighter and intruder.  Some even had the radar removed ( Mk.II (Special) ). The first Mosquito to have an actual NF designation was a MK.X which wasn't proceeded with, and the next mark was the NF Mk.XII which went into production.

Even in the Mosquito Genealogy map, on page 392 it doesn't show an NF Mk.II

[PR19_Kit]

And other books say differently.

Such are the pitfalls of research of course.

[kitnut617]

The Sharp/Bowyer book is supposed to be the definitive book on the Mosquito though ----  (had a look on Amazon to see if any are available, used ones start at C$100, while brand new ones are ....... C$999    )

[PR19_Kit]

How is one supposed to judge between the relative merits of one reference book vis a vis another one? 'Supposed to be' is a judgement made by people who themselves are open to question. Who's to say what is the definitive answer?

And that goes for almost every other statement on here or anywhere else........

[kitnut617]

I think having the Foreword of the book written by Geoffrey De Havilland himself goes a long way Kit --

[PR19_Kit]

<sigh>

Sorry, I refuse to play the 'my references are better than yours' game.

[wuzak]

http://www.mossie.org/Mosquito_var.htm

F.II Fighter. Developed from prototype W4052. Four 20mm cannon and four.303in Browning machine guns. Rolls-Royce Merlin 21 and 23 engines. Two were built experimentally with a rotating dorsal turret equipped with four .303in machine guns. Some examples converted to PR.II.

It doesn't list an NF.II, but:

NF.XII Fighter. Four cannon fighter developed from the NF.II, but with the four machine guns and the A.I. Mk. 5 radar being replaced by centimetric A.I. Mk 8 radar in nose radome. Merlin 21 and 23 engines. The 'standard wing' was not fitted.