Billy Mitchell: Fighters Are Essential to a Daytime Bombing Mission

[rickshaw]

The DH Hornet saw no combat in WWII, not entering service until 1946.

[sequoiaranger]

re: P-38 and their ilk as escort fighters---In Europe they were not so good against the agile single-seaters like the Fw-190 and Me-109. However, to defend against the Allied bombers, Germany used many twin-engined aircraft (like the Me-410 and Me-110) that could be useful in an escort-fighterless sky but would be cut to pieces with even a P-38 escort.

[dy031101]

However, to defend against the Allied bombers, Germany used many twin-engined aircraft (like the Me-410 and Me-110) that could be useful in an escort-fighterless sky but would be cut to pieces with even a P-38 escort.

I can see that the German idea sounded simple enough, but German industry simply couldn't build enough heavy fighters to do anything more than making the Allied bombers pay for their victory or single-engined fighters to keep bomber escorts at bay while heavy fighters did their work.

[KJ_Lesnick]

Weaver

I wonder about smaller, single-seaters. The Whirlwind proved quite adept in combat, and the DH Hornet amounted to a scaled-up Whirlwind.

The Whirlwind was an example of an effective heavy fighter (I don't know what it's range was though) in terms of it's cannon armament -- I should note it wasn't that heavy though, and not actually all that big. 

Other heavy fighters could include the P-38, P-39, P-61, P-63, and F7F. 

• The P-38 had an excellent rate of climb, top-speed, and long-range (especially with drop-tanks) enabling it to escort bombers, sustained agility at medium to low altitudes were very good and a great deal of firepower with early designs sporting a 37mm cannon (later replaced with a 20mm cannon) as well as 4 machine guns, and the means to carry 2,000 pounds of bombs.  It had shortcomings such as the fact that it's roll-rate was a bit poor (it was increased as time went on), it had serious compressibility problems in dives (though I'm not sure if that was due to it being a heavy fighter), and it's agility at high altitude, especially with drop-tanks seemed to have been a little less than ideal, possibly owing to it's wing-loading.
  
• The P-39 was originally fitted with a turbo, though there were reliability issues with it and a new one had to be installed.  The USAAC/F decided to fit it with a supercharger instead as they couldn't find a turbo that was effective enough and small enough to fit in the design, plus some didn't feel the high-altitude performance was all that important.  As far as I know, the aircraft had one major flaw with it's engine configuration (a hit above and behind could easily disable the cooling systems resulting in a huge-fireball), I've never heard anything to suggest it had agility problems, and top-speed though certainly not the best was comparable with a P-40 and F6F (if it had a turbo it would have been faster).  It had a 37mm cannon in addition to 6 machine guns.
  
• The P-61 was essentially a night-fighter and was created by a British request for a turret-equipped night-fighter that could loiter over London for 8-hours.  The aircraft ended up looking like a scaled-up, radial-powered, clunkified P-38 with a turret up-top; it had a crew of 3 with a pilot in the front, a turret-operator in the middle, and a radar-operator in the rear.  The plane was somewhere between the size of a A-20 and a B-25 with a wing-area bigger than both.  The aircraft was surprisingly agile for it's size, but that doesn't really say all that much: It had a good roll-rate (owing to it's interesting roll-spoiler system in addition to small ailerons) which was superior to the De Havilland Mosquito (which variants of it ended up being the RAF's preferred night-fighter) but it had a wider turning-arc, and less power.  In comparison to the best fighters, it couldn't hold a candle to in daylight; the P-61A/B could have afforded to have been a bit faster, though the P-61C was actually able to do like 430-440mph due to a turbocharger and possibly some aerodynamic refinements.
  
• The P-63 was basically an aerodynamically refined, bigger, and faster, P-39 with a turbocharger a heavier bomb-load.
  
• The F7F was almost as big as some light-bombers, and was no lightweight by the standards of a fighter.  Early models weighed in around 23,000 to 24,000, later models approaching 26,000.  Though it was not carrier suitable at first due to poor engine-out performance and the structure was a little flimsy, this aircraft was actually superbly agile, fast-climbing, with a high top-speed, and was loved by virtually every pilot who flew it.  It was also heavily armed, able to carry a torpedo or 2,000 pounds of bombs.  It was originally designed as an escort fighter, and later on developed into a day fighter able to be used as an interceptor, a day-fighter, and some variants were developed with night-fighter capabilities.  Though the USN didn't operate it off carriers during the war, the USMC used it as early as 1944.
  

...


KJ

[rickshaw]

When introduced into service the Whirlwind carried the heaviest armament of any fighter, Kendra.  No other operational fighter carried 4 x 20mm cannon.   It was also the first twin-engined modern heavy fighter introduced into operational service as well, beating the Bf110 by a few months and the P-38 by nearly a year IIRC.   So I rather suspect you're selling it a tad short there.   The P-38 had considerable teething problems as well, which prevented it becoming effective before about mid-1942.  Also, comparing late war aircraft to early war aircraft is like comparing apples and oranges.

[Old Wombat]

The Whirlwind's only major (&, eventually, fatal) failing was being tied too closely to the RR Peregrine engine which had teething difficulties at the wrong time (the beginning of WW2) leading to the Air Ministry to tell RR to stop trying to fix it & concentrate on their lead engine, the Merlin.

As a whif concept, perhaps, if the Peregrine had not had so many teething issues or the Air Ministry had given RR the time to fix it (assuming they could):

How would ongoing development of the Peregrine motor have effected development of the Whirlwind?
Would the Whirlwind have been able to upgrade to a larger engine later, as the Spitfire did?
Would it have needed to?
Given a similar development profile to the Merlin, what sort of performance could the Peregrine have eventually delivered?

I need at least 2 lives!

[Hobbes]

The Merlin was developed to 2000 shp, or 75 hp/litre. Apply the same to the Peregrine, and you get 1500 shp.

The Griffon could be used in place of the Merlin because they have similar dimensions (despite the Griffon having much larger displacement).

The Peregrine is almost as long as the Griffon, which suggests there is room in the Peregrine design to enlarge the cylinder bore to increase its displacement. I don't know if the cylinder bank design allows this, though (you may have to redesign the cooling channels).

[PR19_Kit]

I always wondered why they didn't just stuff two Merlins onto the Whirlwind and have done with it. It would have have almost pre-dated the Hornet's performance by a few years. It's been done on here more than once of course.

Maybe even two Grffons! 

[pyro-manic]

The Whirlwind was designed around the Peregrine. It couldn't have taken Merlins without serious redesign, IIRC.

[RussC]

I always wondered why they didn't just stuff two Merlins onto the Whirlwind and have done with it. It would have have almost pre-dated the Hornet's performance by a few years. It's been done on here more than once of course.

Maybe even two Grffons! 

  How about two Whittle or other early jet powerplants ?

[rickshaw]

The Whirlwind was designed around the Peregrine. It couldn't have taken Merlins without serious redesign, IIRC.

It may have required larger radiators but the Peregrine and the Merlin's dimensions were essentially the same, with the Merlin actually being slightly larger and heavier but putting out substantially more power.

Rolls-Royce Merlin 61

General characteristics

   * Type: 12-cylinder, supercharged, liquid-cooled, 60° "Vee", piston aircraft engine.
   * Bore: 5.4 in (137.16 mm)
   * Stroke: 6.0 in (152.4 mm)
   * Displacement: 1,647 cu in (27 L)
   * Length: 88.7 in (225.3 cm)
   * Width: 30.8 in (78.1 cm)
   * Height: 40 in (101.6 cm)
   * Dry weight: 1,640 lb (744 kg)[nb 15]

Performance

   * Power output: * 1,290 hp (962 kW) at 3,000 rpm at take-off.
         o 1,565 hp (1,167 kW) at 3,000 rpm at 12,250 ft (3,740 m, MS gear)[nb 16]
         o 1,580 hp (1,178 kW) at 3,000 rpm at 23,500 ft (7,200 m, FS gear)
   * Specific power: 0.96 hp/cu in (43.6 kW/L)
   * Compression ratio: 6:1
   * Fuel consumption: Minimum 39 Imp gal/h (177 L/h), maximum 88 Imp gal/h (400 L/h)[nb 17]
   * Power-to-weight ratio: 0.96 hp/lb (1.58 kW/kg) at maximum power.

Rolls-Royce Peregrine I

General characteristics

   * Type: 12-cylinder supercharged liquid-cooled 60-degree Vee aircraft piston engine
   * Bore: 5 inches (127 mm)
   * Stroke: 5.5 inches (140 mm)
   * Displacement: 1,296 in³ (21.2 L)
   * Length: 73.6 in (1,869 mm)
   * Width: 27.1 in (688 mm)
   * Height: 41.0 in (1,041 mm)
   * Dry weight: 1,140 lb (517 kg)

Performance

   * Power output: 885 hp (660 kW) at 3,000 rpm, +9 psi boost
   * Specific power: 0.68 hp/in³ (31.1 kW/L)
   * Compression ratio: 6:1
   * Power-to-weight ratio: 0.77 lb/hp

While the Merlin 61 was substantially later than the Peregrine I, you can get the idea...

The increased radiator area would have increased drag but as to whether the increase in power would have offset that I have no idea.  The increased weight would have been a substantial problem though.

I often wonder why people want to upgrade the Whirlwind when the Mosquito was just around the corner and was much more adaptable and useful than the Whirlwind.   You could use the Whirlwind for two roles (Fighter or Fighter-Bomber).  You could use a Mosquito for multiple roles and it would excel at all of them and at a substantially longer range.

[rickshaw]

How about two Whittle or other early jet powerplants ?

Bit of a problem there.  Where do you put the undercarriage?

[PR19_Kit]

I often wonder why people want to upgrade the Whirlwind.......

Because it's there!   

[rickshaw]

Fair enough.

Has anybody thought about using other engines than from the Rolls-Royce stable?

How about:

Centaurs
Hercules
Sabres

Does anybody do a ~1/60 scale Whirlwind?  Slight larger, to accept the larger engines... 

[Hobbes]

The Merlin was 50% heavier. An extra 500 kg is a lot (more than 10% of the empty weight). I'm guessing the weight would be in front of the CoG, assuming the Peregrines were placed as far aft as possible, against the main wing spar, so a Merlin would stick out another 50 cm.