An early 2-engined carrier based aircraft - worth the effort?

[tomo pauk]

The two engined aircraft for the ww2 carriers is something of a black sheep, the 1st such aircraft worth speaking of being the Sea Mosquito. The USN was offered with such an aircraft, the XF5F.
So - what one could expected from a 2-engined CV aircraft in a ww2 battlefield, against air, ship and ground targets? Would it be too much to expect that each such an aircraft accomplishes well all the three/four main jobs other planes were performing (scouting, air defense, bombing, torpedoing)? What kind of reduction of available aircrafts' numbers is to expect if a navy uses a big number of the 2-engined aircraft instead of 1-engined? Would the 2-engined layout bring out more benefits or problems, safety-wise?

 

[pattle]

What year would early be? I think a larger twin engine aircraft would come into existence only when it was impossible to create a single aircraft capable of doing what was needed of it.

 

[tomo pauk]

I was thinking about 1940-1943 time frame.

 

[Shortround6]

The two engined aircraft for the ww2 carriers is something of a black sheep, the 1st such aircraft worth speaking of being the Sea Mosquito. The USN was offered with such an aircraft, the XF5F.
So - what one could expected from a 2-engined CV aircraft in a ww2 battlefield, against air, ship and ground targets? Would it be too much to expect that each such an aircraft accomplishes well all the three/four main jobs other planes were performing (scouting, air defense, bombing, torpedoing)?

In a word, YES

The XF5F-1 First flies in the Spring of 1940 ( a month or so before the Corsair). What do you have for engines?
You won't get a real number of R-2800s until the end of 1941/beginning of 1942 and even then by robbing some other program.
The Skyrocket had a bit smaller wing than the Corsair (and a bit smaller than a Douglas SBD while using two of the SBD's engines) and a wing about 72% the size of a Curtiss SBC2 and 62% of the size of an Avenger wing.
Blasting your way off the flight deck with power (instead of wing lift) only works IF you have lots of power. Two R-2600's???
A junior F7F ??
Two 9 cylinder Wright Cyclones are NOT going to cut it for an all purpose airplane. It will either be too small to carry the bomber/torpedo load (and fuel) or it will be too big to be a decent fighter ( the XF5F-1 missed it's proposed performance figures by a good margin.)

What kind of reduction of available aircrafts' numbers is to expect if a navy uses a big number of the 2-engined aircraft instead of 1-engined? Would the 2-engined layout bring out more benefits or problems, safety-wise?

Depends on how/ where you fold the wing but figure even with folding the wings just out board of the engine nacelles about twice the width of F4F, F6F or Avengers. 2 engines cut both ways safety-wise. Much more likely to get back to he carrier with one engine out (zero chance with one engine) but landing with one engine out is going to be tricky. Take land based twin engine problems and multiply.

 

[pattle]

I was thinking about 1940-1943 time frame.

I can't really think of anything that it would have been possible to make in that time frame. Although how about a navalised P38, I know such a thing was proposed but rejected, I wonder where they were thinking of putting the arrester hook on it?

 

[cimmex]

First you should build new carriers with hangars large enough for twin engine planes…
cimmex

 

[tomo pauk]

Where do you reckon the Vals and Zeroes were stocked when carrier was at sea?

In a word, YES

The XF5F-1 First flies in the Spring of 1940 ( a month or so before the Corsair). What do you have for engines?
You won't get a real number of R-2800s until the end of 1941/beginning of 1942 and even then by robbing some other program.
The Skyrocket had a bit smaller wing than the Corsair (and a bit smaller than a Douglas SBD while using two of the SBD's engines) and a wing about 72% the size of a Curtiss SBC2 and 62% of the size of an Avenger wing.
Blasting your way off the flight deck with power (instead of wing lift) only works IF you have lots of power. Two R-2600's???
A junior F7F ??
Two 9 cylinder Wright Cyclones are NOT going to cut it for an all purpose airplane. It will either be too small to carry the bomber/torpedo load (and fuel) or it will be too big to be a decent fighter ( the XF5F-1 missed it's proposed performance figures by a good margin.)

Nah, not two of the big radials (though those are tempting). The Twin Wasp and Cyclone 9 will have to satisfy. The wing area should be somewhere around 350 sq ft? BTW, I don't buy the performance figures from Wikipedia, the USN tests give the speed as 357-358 mph at 17300 ft, on 2 x 900 HP, for the unarmed Skyrocket. The weight during the tests was just under 10900 lbs with 277 gals. It took 4.6 min to climb to 10000 ft, 10,5 to 20000 ft.
Sure enough, the fully 'war-capable' Skyrocket will be much heavier, probably around what F4U and F6F were. So the wing loading will be about the same.

Depends on how/ where you fold the wing but figure even with folding the wings just out board of the engine nacelles about twice the width of F4F, F6F or Avengers. 2 engines cut both ways safety-wise. Much more likely to get back to he carrier with one engine out (zero chance with one engine) but landing with one engine out is going to be tricky. Take land based twin engine problems and multiply.

We can remember several important aircraft that wen't featuring much or any of the folding wings - like Sea Hurricane, Dauntless, Zero or Val. SBD and Val were featuring rather big wings, so a folding wing 2-engined aircraft would've require less space.

I can't really think of anything that it would have been possible to make in that time frame. Although how about a navalised P38, I know such a thing was proposed but rejected, I wonder where they were thinking of putting the arrester hook on it?

The arrester hook was supposed to be attached to the central nacelle.

 

[wuzak]

Would a Fairey P.24 type engine count as a twin?

What about tandem engines, such as in the Kawasaki Ki 64 or Arsenal VB-10?

 

[wuzak]

Depends on how/ where you fold the wing but figure even with folding the wings just out board of the engine nacelles about twice the width of F4F, F6F or Avengers. 2 engines cut both ways safety-wise. Much more likely to get back to he carrier with one engine out (zero chance with one engine) but landing with one engine out is going to be tricky. Take land based twin engine problems and multiply.

Apart from when the wings are folded, the Mosquito was close in size to the Avenger. Heavier, however, but one could argue it was far more capable.

 

[Shortround6]

Nah, not two of the big radials (though those are tempting). The Twin Wasp and Cyclone 9 will have to satisfy. The wing area should be somewhere around 350 sq ft? BTW, I don't buy the performance figures from Wikipedia, the USN tests give the speed as 357-358 mph at 17300 ft, on 2 x 900 HP, for the unarmed Skyrocket. The weight during the tests was just under 10900 lbs with 277 gals. It took 4.6 min to climb to 10000 ft, 10,5 to 20000 ft.
Sure enough, the fully 'war-capable' Skyrocket will be much heavier, probably around what F4U and F6F were. So the wing loading will be about the same.

Part of the problem is not getting the plane into the air but getting it back down.

The Power Plant of Brewster F2A-3 2087lbs + 165 for the "engine" section. or 2252lb, this may or may not include fuel tank weight. double it is 4504lbs, The Power plant of an F6F went 3916lb not including fuel system but including 411lb so of engine section, engine, accessories, controls, prop, starting system, etc. so you have a 500-600lb weight penalty for the "twin" to begin with.
Initial Requirement for the Avenger included:

Missions:

1. Attack against heavy surface ships with bombs or torpedoes
2. Heavy smoke laying
3. Scouting
4. Strafing light surface vessels

Performance requirements:

1. Top speed of 300mph with normal fuel
2. Range of not less than 1000 miles while carrying one torpedo or thee 500lb bombs
3. service ceiling of not less than 30,000ft.
4. take-off distance when carring a torpedo and fuel for a combat range of 1,000 miles not to exceed 325ft with a 25kt wind over the deck
5. stalling speed when carrying a torpedo and less than half the fuel load not to exceed 70 mph.

Overall span limited to 60 ft and over all length limited to 39 ft and width with wings folded was 17 ft.

The Avenger did miss a few of those requirements/limits but a jumped up F5F-1 was going to miss a bunch of them. Avenger wound up with a 54ft wing span, 19ft when folded and depending on model 40-41ft in length and 490 sq ft of wing.

Aircraft carriers had limited storage for torpedoes and torpedoes were expensive ( both time and money) so torpedoes would NOT normally be dumped prior to a "standard" landing.

Now these requirements may have been relaxed a bit ( the need for torpedo bombers at 30,000ft was never explained) but shows what the Navy was looking for in 1939/40 and the Curtiss SBC-2 was the dive bomber equivalent. The Curtiss SBC-2 preceded the Avenger time wise ( first flying about 8 months earlier) but need for modifications ( and modifications and modifications and.........) delayed service until after the Avenger saw action.

Trying to combine fighter performance with the strike specification ( bomb load AND range) is the really hard part. Please remember that the F7Fs were intended to operate from the Midway class carriers.

We can remember several important aircraft that wen't featuring much or any of the folding wings - like Sea Hurricane, Dauntless, Zero or Val. SBD and Val were featuring rather big wings, so a folding wing 2-engined aircraft would've require less space.

Barely, an F7F was 32'2" with the wings folded and they arranged the wing fold to be at the edge of the prop circle.

An F5F-1 was supposed to be 21'2" with the wings folded but the wing folds look like they are inside the prop circles. Even when fitted with the longer nose (not the army version) the nose did not extend forward of the props which are rather close together, putting even a skinny fuselage between the props will require moving the engines out.

 

[tomo pauk]

Would a Fairey P.24 type engine count as a twin?

What about tandem engines, such as in the Kawasaki Ki 64 or Arsenal VB-10?

For the Western countries using Merlin or V-1710 the rear shaft could not 'travel' between cylinder banks, contrary to what DB or Hispano engines. However, maybe locating the engines side to side might've worked? The layout similar to P-75, but with two separate engines (instead of one double engine), the coolers moved to wings so more place is available for big bomb or torpedo?

 

[pinsog]

( the XF5F-1 missed it's proposed performance figures by a good margin.)

So what do you guys think the real world performance of an F5F would be? In tests it climbed at 4,000 feet per minute and had a top speed of around 357 mph. Add 4 .50
caliber machine guns and some armor. Even if you cut the climb by 25% down to 3000 feet per minute that is still almost double what a Wildcat could climb at. If top speed
remained around 350 mph, then it will be 20 to 35 mph faster than a Wildcat. Sounds like a better plane to be in when your fighting Zero's to me. At least when a raid has
been picked up on radar, with a climb of 3,000 fpm at least you would always ba able to make your first pass from above. AND when your taking on flights of Vals lined up
like ducks, those 4 .50's all concentrated together would be devistating. It might not be a Corsair, but it sounds like a lot better machine than a Wildcat for defending the
fleet.

So, best guess on F5F performance when it is ready to fight?

 

[Shortround6]

It is hard to figure what the combat capability of the F5F would be as the engines it was tested with lost power rapidly with altitude. the 1200hp rating was only good to about 1800ft (yes eighteen hundred) in low blower and 1000 hp was available to around 13,600ft in high blower. You are down to about 865hp per engine at just under 20,000ft. The Wildcat had about 1040hp at 18400ft or 1000hp at 19,000ft. Later versions of the Cyclone got a little bit better. Big improvements to the Cyclone (1300-150 hp take-off) don't show up until some time in 1943.
Somebody has said the F5F only had 227 gallons of fuel which is not a lot unless you are using drop tanks from the start.

Vision for carrier landing the F5F as built is best described as dismal given the location of the cockpit, wing and engines.

 

[davparlr]

If it could have been made to work on a carrier, the A-20A, possibly lightened (maybe even a DB-7 which was not much larger, or heavier, than the TBF), could have been a potent weapon for the early war Navy. With a top speed higher than the Zero, it would have been difficult to counter and certainly would have caused, pardon pun, havoc with the Japanese in the Solomons. Of course it would have taken a similar mind set change for the Navy to adapt to larger, faster aircraft, just as the AAF had to do, although not well, with the likes of the B-26. I think the effort would have been worth it and it might could have been made to work.

 

[Shortround6]

A major problem is what size and weight aircraft the carriers were designed to operate.

1. What size catapults (if any) the early carriers had.
2. What weight and speed the arresting gear was designed to handle, an A-20 at 20,000lbs stalls at 110-115mph. the later A-20Gs went 17,200lb empty, the A-20Cs went 15,625lbs empty. An Avenger weighs just under 18,000lb MAX loaded.
3. What weights and vertical impact speeds where the flight decks designed to handle.
4. What impact does a radical change in aircraft type have on logistics and operations?

According to one source aviation fuel capacities for US Carrier classes were as follows.

Saratoga in 1942-----137,450 gal
Ranger---------------135,840 gal
Yorktown------------177,950 gal
Wasp----------------162,000 gal
Essex----------------240,000 gal
Independence------- 120,000 gal
Midway--------------350,000 gal

Most of the escort carriers carried 90-100,000 gals.

Bomb (and torpedo/depth charge) magazines may have been sized in proportion.

A lot of the restriction of aircraft size for carriers was to fit them on the lifts/elevators and in some cases the navy may have wanted two aircraft on the lift at one time.

see: http://www.navsource.org/archives/02/020603.jpg

Foremost devestaor is sitting on one lift/elevator

Picture of carriers under construction:

I believe there were 3 lifts/elevators in this class, one forward, one midships just aft of the island/stack and one at near the stern.

If the goal is to have better fighters available in 1942 it doesn't do much good if the existing carriers cannot support them without some sort of refit program.

 

[pinsog]

It is hard to figure what the combat capability of the F5F would be as the engines it was tested with lost power rapidly with altitude. the 1200hp rating was only good to about 1800ft (yes eighteen hundred) in low blower and 1000 hp was available to around 13,600ft in high blower. You are down to about 865hp per engine at just under 20,000ft. The Wildcat had about 1040hp at 18400ft or 1000hp at 19,000ft. Later versions of the Cyclone got a little bit better. Big improvements to the Cyclone (1300-150 hp take-off) don't show up until some time in 1943.
Somebody has said the F5F only had 227 gallons of fuel which is not a lot unless you are using drop tanks from the start.

Vision for carrier landing the F5F as built is best described as dismal given the location of the cockpit, wing and engines.

Let us assume, if we may, that the F5F is equipped with the same engine as the F4F Wildcat. I wouldn't think that switch would be a big leap for the design team. Now you have a twin engine aircraft with 1040 hp per engine at 18,400 ft. Add 4 .50 machine guns and try to guess performance if you can/don't mind. I really think that it was a missed opportunity for the US to have a good performing aircraft with the available technology. If nothing else, it could have been great for land bases such as Midway and Guadalcanal.

 

[Shortround6]

The R-1830 engines were about 200lbs heavier per engine, not including the inter-coolers. It also does not include a difference in propellers which might be needed if trying to transmit 15% more power at altitude, or maybe not. As originally conceived the F5F was to use P&W R-1535 two row engines of smaller diameter with two stage superchargers but P&W stopped development of this engine. Why they went to the Wright Cyclones instead of shifting to the bigger P&W engines I don't know. I can speculate that it had something to do with the CG and weight problem as the engines are the furthest thing forward on the plane unlike The Lockheed Hudson and several other planes that seemed to use the engines interchangeably (so did the Curtiss Hawk 75 and the F4F but they also balanced the weight and length of the engines and were designed for the longer/heavier two row engine to begin with).

I dislike guessing at performance because so many things change. The P&W engines are smaller in diameter which helps drag but they use inter-coolers which add drag. The engine Nacelles have to be redone adding to the fact that the landing gear doors were never sorted out on the prototype. Smaller cowls may help the vision problem a little bit. Program got canned when Prototype F4U handily outran the the F5F. By the time you get a service F5F it is going to weigh as much as an F4U or F6F and have more drag.

 

[Glider]

I like the idea of a naval Beaufighter. It was early enough, the engines were close to the fuselage and with folding wings the footprint wouldn't be huge. As a strike aircraft of the time it had few peers and whilst it wouldn't be able to handle single engine fighters, it could take on anything else. Finally its firepower would be devastating against attacking bombers, it had plenty of ammunition, plus of course it had a respectable range and an ideal view of the deck for landing.

You could do worse

edit the undercarriage looks pretty solid as well

 

[Aozora]

I like the idea of a naval Beaufighter. It was early enough, the engines were close to the fuselage and with folding wings the footprint wouldn't be huge. As a strike aircraft of the time it had few peers and whilst it wouldn't be able to handle single engine fighters, it could take on anything else. Finally its firepower would be devastating against attacking bombers, it had plenty of ammunition, plus of course it had a respectable range and an ideal view of the deck for landing.

You could do worse

edit the undercarriage looks pretty solid as well

Two major problems - the only British carriers that could possibly have accommodated folding wing Beaufighters were the Courageous class and Ark Royal - there's no way the Illustrious class could have serviced Beaufighters in their hangers unless the Beaufighter's wings could be arranged to fold parallel with the fuselage a la the Grummans, otherwise Beaufighters would have been parked and serviced on deck at all times. Another major problem was the aviation fuel capacity of British carriers: of those available from 1940-42 avgas capacity was:

Courageous Class = 34,500 imp gal
Ark Royal = 100,000 imp gal
Illustrious Class = 50,540 imp gal

vs American carriers

Lexington Class = 114,495 imp gal
Yorktown Class = 148,332 imp gal
Wasp = 134,946 imp gal
Essex = 199,920 imp gal

Each Beaufighter would have needed roughly 550-624 gallons of fuel, depending on the fuel tank configuration; even a squadron of Beufighters would have severely restricted deck space, thus the size of a carrier air group, but their need for lots of fuel would have drastically reduced the numbers of sorties that could have been flown.

 

[tomo pauk]

The Gloster F.9/37 looks part.

Gloster F.9/37 - Wikipedia, the free encyclopedia

Stick Merlins on it, from early 1941 on.