Nightfighter for the USAF: you're in charge

[davebender]

Spare has nothing to do with it. The Mosquito factory production order would be increased by 500 aircraft. If that requires factory expansion then the factory gets expanded using funds which historically created P-61 assembly plant.

 

[tomo pauk]

Hello, I've tried to clump together parts dealing with different proposals:

Considering this a bit more the best bet for a quick dirty night fighter is probably trying to stick turbo Allisons onto an A -20 airframe.

The wright R-2600 seems to have trouble with having a high altitude version although this is inferred by no high altitude version ever making it to production.

How about the turbocharged R-1830 aboard the A-20? The engine is rated for 1200 HP in the P-43 from the get go (1940-41?), vs. 1150 HP for the V-1710 prior early 1942? Drag would equalize speed, but weight would be a bit on Twin Wasp's side.

Switching to turbo-Allisons on the A-20 gives up take-off power although by not carrying bombs this may help the weight-take off problem. Guns and ammo have to be kept to well under 2000lb though
Since the 1325hp turbo Allison shows up in P-38s in Feb/March of 1942 it seems viable and at any altitude much over 13-15,000ft is going to give more power than the R-2600s. Perhaps the larger engine nacelles of the A-20 (you still need to fit the original wheels/tires) offer space for a better intercooler set up than the wing leading edges of the P-38 so the A-20 night fighter won't have the problem with engine restrictions that some of the mid P-38s had?

The 4 cannons their ammo on the P-61 weighted 1000-1050 lbs (and .50 cal turret, guns ammo almost 1300 lbs) - we should be well within limits.
The better intercooler set-up should be able to push the V-1710 above 1300 HP indeed.

Another thing that might do well - V-1650-1 on the A-20? BTW, the wing of the A-20 was stressed to take both R-2600 and turbo - the single stage R-2800 should not weight more than that?

P-38 isn't big enough to hold the very early radars without playing with the fuselage although it didn't have to wait as long as it did to get the navy radar pod.

Was it the 'black boxes' or antennae? Maybe install some of the black boxes in the 75 gal tank?

If the Army and Douglas had got off the stump perhaps the A-26 nightfighter could have showed up earlier but you still have the engine problem for high altitude performance and the A-26B empty weighed with a few hundred pounds of a P-61B empty and the P-61 already had two stage engines.

Hmm- how about A-26 plus two stage engines? The wing was smaller (540 sq ft vs. 664) and of 'faster' profile - laminar flow wing; should push such an A-26 to 400 mph?

The Turbo P-61 has a bit of a problem in that the performance numbers for the P-61C need the R-2800-73 (same engine used in P-47M) engine so as good as that option may be it doesn't do any good until Fall/Winter of 1944.
Using the -21 engine out of the P-47B/C does increase the power at altitude but also picks up the weight of the turbo system (a P-61C picked up about 2000lbs in weight over a P-61B), perhaps an early version with lower powered engines doesn't need the bigger props used on the P-61C? or can save some weight other places?

Simply pulling the turret of the P-61 doesn't change a whole lot, 3-5mph in speed and with about 800lbs for the turret and 500-620lbs for .50 cal ammo (on a 30-31,000lb airplane clean) it does what for climb? Smaller fuselage will help but that takes longer once the drawings are finished for the big fuselage (when do you ditch the the turret in the planning stage?)

How about turbo engines, like the ones used on the P-47C/D, whose increased weight would be compensated via deletion of turret?

 

[yulzari]

Could we define the question more closely? When do I get to be in charge? When do the night fighters need to be in service? Certainly there was no spare Mosquito night fighter capacity IOTL. The USAAF was desperate to get Mosquitos to replace their tired Bristol Beaufighters in the Mediterranean but only began to replace them at the very end of the war. Starting in 1942 your only serious possibility is to use aeroplanes already in production, P70, P38 or maybe shoehorning an operator into a Mustang. But remember, whatever you use it will come out of existing numbers initially until the same resources that led to the P61 come on line.

In 1942 I would go with tweaking the Maryland as the source airframe to tweak. The Baltimore combined the new engines with greater weight. How about combining them with a bombless 2 man Maryland. By 1944 one might consider a P38.

 

[OldSkeptic]

The US made a big strategic mistake not setting up Mossie production in the US. The reality is that demand for Mossies was so high that the UK was very reluctant to give any to the US, though they did get some for photo recon.

Apart from having it as a nightfighter, and long range photo recon, as a fast daylight bomber (and for target marking) it would have been invaluable to them.

The P-61 was a bit of a kludge, complex, expensive and not that fast in real world deployment, bit like an uprated Beaufighter. Against the late war nuisance raids by night flying Me-410s and Fw-190s it would have struggled... a lot. Even the Mossies with Merlin xx series engines had to be boosted with No2 to be used against those (shortages delayed the Merlin 60 series nightfighter Mossies, with priority going to recon and bomber versions). Against V1s it was not even in the game.

Another problem was range, it was too little on internal fuel only, which meant speed sapping external tanks.

As an intruder, though it was faster than the 110s and early Ju-88s (without external tanks) you wouldn't want to go up against a 219 (or even a late model Ju-88G)in it. Common intruder tactics were to pick up a German nightfighter coming in from the rear, quick turn and acquire on radar and go for the kill. That requires speed, acceleration and manoeuvrability. Could a P-61 out turn a 110, 88 or 219, then accelerate fast enough (after losing speed in the turn) to catch up again?

That was the problem with the Beaufighter, didn't have enough speed to catch the later model German nightfighters (even struggled against 110s) and its range was too low for intruder operations.

So I'd vote for setting up Mossie US production lines for their night fighters and also reap the benefits of their other uses.

 

[Shortround6]

How about the turbocharged R-1830 aboard the A-20? The engine is rated for 1200 HP in the P-43 from the get go (1940-41?), vs. 1150 HP for the V-1710 prior early 1942? Drag would equalize speed, but weight would be a bit on Twin Wasp's side.

Maybe but the Twin Wasp dead ends, nowhere to go so you need a second fighter soon or redo the A-20 engine installation a second time.

the 1200hp versions were 20mph slower than the 1600hp versions at the lower altitudes. With the turbos you might split the difference at medium/high altitudes. more drag than the base Twin Wasp version. The extra guns and radar antenna will not help. Classic turbo trade off, slower below 15,000ft, about tied between 15,000 and 20,000 and faster above 20,000ft. The 1600hp version might still have over 1000hp at 19,000ft although it is fading fast.

And we start getting into the armament question. The original 1200hp DB-7s carried eight or twelve .303 guns in nightfighter roles. The .50 cal weighs about 3 times what a .30 or .303 does and the ammo is about 5 times heavier per round. A lot of the P-70s used four 20mm cannon, either in the nose or in the belly pack but as far as I know they used 60 round drums. Rather limits firing time even if the installation is a lot lighter than the 200 round belts used in the P-61( and they often flew with reduced ammo)

The speeds/performace for the 1200hp versions are often for a weight of 15,030lbs.

Hmm- how about A-26 plus two stage engines? The wing was smaller (540 sq ft vs. 664) and of 'faster' profile - laminar flow wing; should push such an A-26 to 400 mph?

It might, depends on altitude. You want two stage engines you need the inter-coolers and it is not really the weigh of the inter-coolers but the drag. Unless you have doors/flaps to seal off them when you aren't using them.

How about turbo engines, like the ones used on the P-47C/D, whose increased weight would be compensated via deletion of turret?

Here we get back into the timing thing. Late model P-47D engines are going to give you a lot more power high up and a lot more power down low. Early P-47 engines are going to give more power up high and zip (no) extra power for take-off or down low.
WHEN do you want it? and you have to start planning not only the aircraft but engine production and allocations up to year before the planes show up in squadrons in more than handfuls. Once you are tooled up and ready to go new, improved dash numbers of similar engines can be introduced with little trouble but switching from single stage to two stage is a bit harder. I have no idea of the reasoning but Ford never made a two stage R-2800 (although many of the engines they made were turboed) while Nash Kelvinator never made a single stage R-2800 and they built 2692 R-2800s in 1943 and 9259 R-2800s in 1944. Chevrolet and the P&W Kansas City plant both come in in 1944 with single stage R-2800 C series engines, having never built a B series engine.

 

[wuzak]

I have no idea of the reasoning but Ford never made a two stage R-2800 (although many of the engines they made were turboed) while Nash Kelvinator never made a single stage R-2800 and they built 2692 R-2800s in 1943 and 9259 R-2800s in 1944.

Simplify the production line, allowing more to be built?

 

[Shortround6]

Could very well be, only the Home plant/s built B's and C's with both single and two stages but that is to be expected.

Just trying to point out that allocating resources was often done well in advance and with good reason. Hartford and Kansas City are almost 1200 miles apart and the steel mills are in between. Steel allocations (and other alloys/materials) have to made and transportation arranged (and the bulk went long distance by rail) well in advance of actual production if things are to run smooth and production kept high. Individual plant complexes could have several thousand subcontractors.
as for distance it would be like the Germans having one satellite plant in Paris and another in Bucharest and trying to coordinate the two.
Programs often took on a life of their own because once started you could have parts for hundreds of airframes or engines in process at various stages even if not actually in the assembly factory.

 

[Koopernic]

Mosquito production was set up in Australia and Canada. One issue in Australia was that when substitute timbers were used the aero-elastic properties of the wing changed and handling properties developed.
Mosquito was not that easy to produce and used all sorts of odd ball wood, such as Ecuadorian timber. Perhaps Hughes could have built them.

 

[FLYBOYJ]

I'll get on my anti-wood soap box again.

Although the Mosquito was an excellent aircraft, wood as a whole does not lend itself well in the field, especially in climates with wide ranges of temperature and humidity changes and performing repairs in the field are a lot more difficult than aluminum. Case in point - post war Mosquitoes that were sent to Israel and Dominican Republic. They were basically falling apart prior to being removed from service

 

[GrauGeist]

...wood as a whole does not lend itself well in the field...

This was one of the major curses of the Ta154 project, also. Once they got past the engine supply issues, they discovered that the wings tended to delaminate.

 

[Shortround6]

A problem with more sophisticated wood structures like the Mosquito and some others compared to simple wood structures (think Piper Cub) is that you are not dealing with a whole lot of individual wood pieces held together with simple glue and screws that can be replaced fairly easily when they do deteriorate. If you are dealing with large areas of laminated wood and/or some fancy glues/adhesives/bonding agents (not talking just the Mosquito here, the US built a number of "wood" planes in the early 40s using some pretty fancy bonding techniques) "when" the time comes for 'field' repair things can get pretty complicated. Like if the skin starts to de-laminate where do you get the multi-ton press to push it back together even if you can get the right glue.
A lot of glues require a certain temperature range while curing in order to reach full strength, not too cold or too hot. That was a problem with some of the US construction, the fuselage (the part made of the laminated wood and "glue") had to be baked in an autoclave (or at least a fuselage sized oven) for a number of hours. Hard to find in the field The US construction may have stood up to weather fairly well but repairing battle or crash damage may have been more than a bit difficult. Russian construction used wood impregnated with a phenol-formaldehyde resin, Just getting another chuck of birch or fir and making it the right shape and gluing/screwing it in place is NOT going to give you the same strength and just coating the piece with the same resin isn't going to work either.

A "normal" wooden aircraft requires a certain skill set to maintain that is different than a metal aircraft. "Advanced" or sophisticated wooden aircraft may require equipment and/or equipment that is not available to maintainers in the field. And unless you use enough resin/epoxy/glue to reduce the wood to a supporting role for the 'chemicals' much like glass mat is a support in fiberglass wood is going to last a much shorter time when exposed to the elements.

 

[tomo pauk]

Maybe but the Twin Wasp dead ends, nowhere to go so you need a second fighter soon or redo the A-20 engine installation a second time.

You are right here, with V-1710s aboard the A-20 should be doing above 380 mph when 1600 HP versions are available? The turboed Twin wasp would have the advantage in timing - late 1941 maybe, after the 1st reports from the BoB are known in the USA?

the 1200hp versions were 20mph slower than the 1600hp versions at the lower altitudes. With the turbos you might split the difference at medium/high altitudes. more drag than the base Twin Wasp version. The extra guns and radar antenna will not help. Classic turbo trade off, slower below 15,000ft, about tied between 15,000 and 20,000 and faster above 20,000ft. The 1600hp version might still have over 1000hp at 19,000ft although it is fading fast.

The speeds/performace for the 1200hp versions are often for a weight of 15,030lbs.

The 1200 HP versions were actually having 1100 HP at 6200 ft, and 1000 HP at 14500 ft (no ram) - the turbo would be about equal under 10000 ft, and superior above? Above 14500 ft, the turbo R-1830 has more power than R-2600 on A-20s/P-70s; the P-70s were criticized because of bad hi-alt performance.
The R-2600-23 (from A-20/P-70) was making 1400 HP at 10800 ft; the R-2600-9 (from B-25) was offering some 150 HP more at 12000 ft; at 17500 ft it was ~1060 HP vs. 1200 HP - the -9 engine should be a better choice than the -23.

And we start getting into the armament question. The original 1200hp DB-7s carried eight or twelve .303 guns in nightfighter roles. The .50 cal weighs about 3 times what a .30 or .303 does and the ammo is about 5 times heavier per round. A lot of the P-70s used four 20mm cannon, either in the nose or in the belly pack but as far as I know they used 60 round drums. Rather limits firing time even if the installation is a lot lighter than the 200 round belts used in the P-61( and they often flew with reduced ammo)

I'd go with 6 HMGs, especially if the 1750 HP R-2600 or 1323 HP turbo V-1710 is aboard. Though, closely-packed 12 apostles (= .30s) should've bring a lot of problems for any pre-1943 bomber?

[re. 2-stagers on A-26:] It might, depends on altitude. You want two stage engines you need the inter-coolers and it is not really the weigh of the inter-coolers but the drag. Unless you have doors/flaps to seal off them when you aren't using them.

The 2-stage engines were providing circa 1800 HP from 5 to 15 kft, vs. 1600 HP from 5 to 13.5 kft for the 1-stagers - should at least equal the low alt performance of the A-26. Above 15000 ft, it would've been a really fast bird. The water injection was available for the 2-stagers, unlike for the 1-stagers of the R-2800 B series - that gives another 200-300 HP under 20000 ft in 1944 and on.
The intercoolers were a worthwhile tradeoff on most, if not all engine versions.

Here we get back into the timing thing. Late model P-47D engines are going to give you a lot more power high up and a lot more power down low. Early P-47 engines are going to give more power up high and zip (no) extra power for take-off or down low.

2 x 2000 HP should be more than enough for a nightfighter to take off Above 16-17000 ft, the difference in power is notable vs. 2-stage versions.

WHEN do you want it? and you have to start planning not only the aircraft but engine production and allocations up to year before the planes show up in squadrons in more than handfuls. Once you are tooled up and ready to go new, improved dash numbers of similar engines can be introduced with little trouble but switching from single stage to two stage is a bit harder. I have no idea of the reasoning but Ford never made a two stage R-2800 (although many of the engines they made were turboed) while Nash Kelvinator never made a single stage R-2800 and they built 2692 R-2800s in 1943 and 9259 R-2800s in 1944. Chevrolet and the P&W Kansas City plant both come in in 1944 with single stage R-2800 C series engines, having never built a B series engine.

The nightfighter will draw a token number of any type of engines in the USA, which, of all the countries, can allot them for that niche.

 

[davebender]

WWII Canada was a huge aluminum exporter. IMO Canada should have been designated primary producer for the aircraft which would have allowed aluminum construction.

Let British furniture manufacturers build something else such as gliders, landing craft or PT boats.

 

[Shortround6]

WWII Canada was a huge aluminum exporter. IMO Canada should have been designated primary producer for the aircraft which would have allowed aluminum construction.

Let British furniture manufacturers build something else such as gliders, landing craft or PT boats.

While raw materials are important there is a lot more to manufacturing than that. Production facilities are important. Furniture manufactures are NOT boat builders. Just because you can make a 5-6 drawer chest of drawers or a desk doesn't mean you can make a 70-80ft boat.

Aluminum ingots don't fly very well, you need rolling mills to turn the ingots into sheets and extrusions, you need factories to turn the sheets and extrusions into actual airframes.

In 1938 Canada built 200 aircraft TOTAL and the major type produces was..........wait for it..........The DH Tiger Moth!!!

DO you send the raw materials to the factories or do you send the factories and the workers to the raw materials?
BtW, where are the landing gear and brake makers? Where are the engine makers, where are the instrument makers, Hydraulic system makers, electrical system makers etc, etc, etc. ????

 

[yulzari]

For Mosquito tropical delamination one might want to visit the myths thread. There was a problem with a supplier using poor techniques. This was identified and dealt with in future production. The RAF used Hornets in Malaya for some years without problems so tropical Mosquitoes can be done. NW Europe is far wetter than Israel and wartime Mosquitos stood out in the rain much of their lives.

Having said that I still would look at using the Martin Maryland as the base airframe in the USA and using the production line that went on to the Baltimore IOTL.

 

[Shortround6]

It is not so much how wet an area's climate is, wooden boats do stand up fairly well after all, but extremes, long wet seasons alternating with long dry seasons. It takes weeks/months, not days, for wood, to dry out and shrink and more than one rain storm to raise the humidity enough for the wood to absorb enough water to swell again. It is the alternating shrinking and swelling that can play havoc with joints/lamination's.
Paint and other sealers do a good job of protecting wood from rain but they do not form a 100% vapor barrier.

 

[Glider]

For an early fighter then you would be hard pushed to better the Beaufighter so build them under license. For a later aircraft build a new aircraft and keep tight control on its weight. The P61 was too big, too complex and too late.
The body of the aircraft didn't need to be that size, two crew 4 x 20mm and the radar could easily be carried by a smaller airframe.
Converted bombers tend to be too large and US bombers tended to be bigger than most.

 

[tomo pauk]

The Beaufighter has the wing area some 10% greater than the A-20, but the P-61 was really big aircraft, indeed. The Beau made in the US (leaving the politics aside, eg. it would be a daunting task making that happen) would also need some US-built engine to power it. If we want 1750 HP version of the R-2600, the A-20 would be readily available for that. There is also a question of armament - 4 drum fed 20 mm vs, say, 6 belt fed .50s in the A-20?

Agreed re. P-61, if the requirement for the turret is nixed early enough, the NF can be built in a somewhat smaller size, that would benefit both performance and range.

 

[Glider]

The A20 didn't have the performance and never would have in particular the climb. In action the main problem with the A20 was that it took too long to get to the height required and nothing will change that.
The Beau had the wing it needed but a lot of the drag comes from the body of the aircraft and bombers generally are larger than fighters

 

[Shortround6]

Some A-20s were actually faster than the Beaufighters, although not by a lot. The British didn't like the A-20 at first because of it's narrow fuselage. Although after building the Hampden they didn't have lot of room to talk

A-20s had engines that had an FTL of under 12,000ft. Performance would tend to fall off at altitude. The problem was never seriously looked at as the Night fighter A-20s were looked at as trainers. A fair number of them also had the armament mounted in under fuselage trays which did nothing for performance.