Kevin J
Banned
Que?
Twin engine fighter for Ark Royal and Illustrious class?
- Thread starter Admiral Beez
- Start date
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Shortround6
Major General
One site says a stalling speed of 78mph. Another comments on long take off run.
There is a lot more to being a carrier aircraft than fitting on the lift.
Kevin J
Banned
The Miles M.39B Libellula fits the requirement perfectly, well almost, it's timing is 5 years too late.
- Thread starter
- #44
Admiral Beez
Major
IDK, it may be a good test bed for the wing ideas, but I don't see that as a fighter. Now, the Curtiss Ascender, maybe.The Miles M.39B Libellula fits the requirement perfectly, well almost, it's timing is 5 years too late.
Shortround6
Major General
Well, you are going to get reactions of ;
"OMG, what an absolutely spiffing idea, How soon can we get one"
to
"I say, Nigel, have you heard what tosh those Yanks are up to? First it was monoplanes and now it is twin engine carrier aircraft, Ha Ha"
Now at some point in 1939 the Admiralty issued specifications for both the Firefly with Griffon engine and the Blackburn Firebrand. Other planes from other makers were proposed on paper with most using either the Griffon or Sabre engine. There were actually several specifications issued in 1939.
N.8/39 with 7 proposals with a variety of engines. None made it to flight stage and NAD.925/39 with about 11 proposals of which only the Firefly and Firebrand made it to flight stage.
The smallest and lightest was Griffon powered Spitfire with folding wing (proposed in 1939). Supermarine also proposed a "stretched" Spitfire powered by a Sabre engine.
The need for any proposal using two engines for the job of fighter seems to be pretty slim. Most of the Griffon Proposals in 1939 were estimating 1600hp for the engine. The Sabre estimates would have been 2000hp or more.
wuzak
Captain
The Curtiss XP-55 Assender would not have been available for the war. Its first flight was in July 1943.
It also had an excessive take-off roll (so not much ascending there) and very problematic stall characteristics.
Of the three prototypes, two crashed. The first prototype flipped on its back during stall tests and fell inverted for 20,000-odd feet. Sounds like an ideal carrier fighter to me!
If the Royal Navy wanted a twin engine fighter, the F5F Skyrocket should do anything they needed almost as tested. Add armor plate and armored glass, 100-150 pounds, self sealing material probably displaced enough fuel for the weight to be about the same. Replace ballast with actual guns, either 4 50's or even 8 30's, (never been a fan of rifle caliber guns in a fighter, but 8 30's concentrated in the nose would be 9600 rounds per minute, 160 a second, all in an area of perhaps 18x18 inches. That would give the rear gunner in a Stuka cause to consider his mortality...). I think, but not sure, that most attacks on British Carriers were unescorted, if that is correct, then you have a fast for the time period, fast climbing, tough, built for carrier ops fighter that had a shorter take off than an F4F-3 Wildcat. Wings should be folded like a Wildcat for clearance in the hanger. If they wanted longer range they could add 75 gallon tanks in each outer wing giving around 400 gallons internal fuel. If they wanted more performance, they could add turbochargers, or P&W 2 stage engines, or P&W with turbochargers, or maybe even hang a pair Merlins on it. But unless they were tangling with 109's or 190's the original should be able to deal with any German bombers they encountered without modifications.
wuzak
Captain
When could they expect the miracle Fw 187 F5F? Mid 1943?
Merlin F5F? Might be a bit nose heavy.
Merlin F5F? Might be a bit nose heavy.
F5F would needed to be built instead of the Wildcat. Since it was essentially a 2 engine Wildcat it shouldn't have been a problem. When you look at the timeline of the F5F it becomes pretty apparent that they simply didn't work on it. I would guess that between developing the Wildcat, Hellcat and Avenger they were already stretched pretty thin on resources.
Not sure why a Merlin version would be nose heavy, the engines would be scooted back under the wing like a turbo prop if you used a V12 engine
Is there a reason you don't think it could have done the job for the Royal Navy? It flew well, handled well, climbed well and was over 30 mph faster over the entire flight regime than a Wildcat with all armament concentrated in the nose. As I said, if it didn't have to tangle with 109's it should have been perfect against German bombers and Italian torpedo planes
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wuzak
Captain
If you "scoot back" the Merlins, where do you put the undercarriage?
The Merlin is longer and heavier than the R-1820, And you have to put a radiator for each engine somewhere.
The first flight of the F4F was in 1937. The first flight of the F5F was in 1940 - two months after the first production F4F rolled off the line.
I doubt that the F5F would be ready in time to be of much use for the FAA, certainly not a Merlin version.
The Merlin is longer and heavier than the R-1820, And you have to put a radiator for each engine somewhere.
The first flight of the F4F was in 1937. The first flight of the F5F was in 1940 - two months after the first production F4F rolled off the line.
I doubt that the F5F would be ready in time to be of much use for the FAA, certainly not a Merlin version.
wuzak
Captain
If the FAA were going to use the F5F they would probably need the first deliveries in 1940 or 1941.
The first delivery of a Martlet to the FAA was in mid 1941, the first with folding wings was in August 1941.
No way the F5F is going to match that timeline.
The first delivery of a Martlet to the FAA was in mid 1941, the first with folding wings was in August 1941.
No way the F5F is going to match that timeline.
Shortround6
Major General
Yes, but a Merlin powered F5F would require mini 4 blade propellers for ground clearance which come in handy for the Super Whirlwind 
.
Seriously, the F5F is somewhat over rated. With no armor or self sealing tanks it was only about 1 minute quicker to 20,000ft than the F4F with protection. Climb near sea level may have been fantastic but climb at 20,000ft with the Cyclone engines seems to have left something to be desired. Service ceiling was about 2,000ft lower. Combat ceiling would be lower.
.Seriously, the F5F is somewhat over rated. With no armor or self sealing tanks it was only about 1 minute quicker to 20,000ft than the F4F with protection. Climb near sea level may have been fantastic but climb at 20,000ft with the Cyclone engines seems to have left something to be desired. Service ceiling was about 2,000ft lower. Combat ceiling would be lower.
Landing gear with Merlins is a problem. I'll concede the Merlins wouldn't work without major redesign.
The Wildcat was almost completely rebuilt after it lost out to the Brewster Buffalo. If Grumman had dropped the Wildcat and built the F5F instead, I believe it would have followed the same timeline as the Wildcat. If you read the timeline on development it becomes obvious that it simply wasn't being worked on.
The only actual test we have on the F5F looks like they used normal power for everything but takeoff. Takeoff power was as you know 1200 hp at 2500 rpm. Apparently, if you look at the test, they used 1000 hp at SL and 4500 feet, 900 hp at 7300 and 14,000 feet, and whatever the engine produces at 17,300 ft, 20,000 ft and 30,000 ft. I'm certain the reported 4,000 ft per minute climb rate was achieved by using takeoff power for initial climb up to whatever altitude they could hold that rating, 4000-4500 ft or so? As I've said before, turbo chargers giving 2400 hp up to 25,000 feet would have made this thing a world beater in my opinion.Yes, but a Merlin powered F5F would require mini 4 blade propellers for ground clearance which come in handy for the Super Whirlwind
Seriously, the F5F is somewhat over rated. With no armor or self sealing tanks it was only about 1 minute quicker to 20,000ft than the F4F with protection. Climb near sea level may have been fantastic but climb at 20,000ft with the Cyclone engines seems to have left something to be desired. Service ceiling was about 2,000ft lower. Combat ceiling would be lower.
wuzak
Captain
So you need for Grumman to come up with the concept a couple of years before they actually did?
Shortround6
Major General
Yes, they would have.....................if
1. turbos weighed nothing.
2. turbos took up no volume.
3. turbos actually worked (actually they worked pretty good, it was the turbo controllers that caused most of the trouble for several years, see loss of the XP-50 for indications of problems)
4. Turbos caused no increase in drag, Lockheed was about the only company to get come close on this one and their intercooler was rather lacking in capacity for increased power.
and having 1200hp per engine at 25,000ft doesn't help as much as it might if you have propellers sized for 8-900hp at 25,000ft.
To me the F5F and Fw 187 have a few of the same problems in discussions. They have the ability to morph into whatever configuration suits the argument of the moment without regard for how that change or changes impact other characteristics/performance areas of the plane.
as for the test
Looks like? By the spring of 1941 the Wright Cyclone G205 engine was rated at 1200hp military power to 4200ft and 1000hp at 14,000ft, both at 2500rpm. When those flight test numbers were actually recorded we don't know but the date on the sheet is way late.
And I really doubt the claimed 383 mph speed for this plane even using military power if top speed was 358mph using max continuous. Some how the F5F picks up 25mph going from max continuous to military power while a P-38 only picks up around 10-12mph?
Grumman submitted its bid for the F5F in April 1938 and had a full scale model built by October 1938. By October 22, 1938 it was at NACA for wind tunnel testing which was completed by March 1939. First flight was April 1, 1940. February 1, 1941, 11 months after first flight, it was dived vertically to 505 mph. 11 months after the first flight it is still the only prototype. The chase plane for the first flight was the XF4F-3 and I think there was only 1 or 2 Wildcats at that time, the production line wasn't running yet.
The Avenger was ordered in April 1940 and first flew in August 1941 and made its combat debut at Midway, 10 months after its first flight.
The turbocharged XP50, same wing and nacelles, was ordered November 25, 1939, first flight was 18, February 1941.
Based on all of this, especially the Avenger timeline, I think the F5F could have been and should have been in squadron service in the same timeline as the Wildcat. Squadron service by early 1941 at the latest. Personally, I would have had them testing turbocharged models as soon as production started instead of wasting time on the XP50.
Also, if you add 500 pounds of turbochargers and 150 pounds of armor and armored glass, weight goes from 10,900 to 11,550 with 2400 hp up to 25,000 feet. That means it has 100 more hp than a P38, weighs 3,000 pounds less, can be dived vertically to 505 mph and is carrier capable. does that sound good to you for a 1941 carrier fighter?
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In all of our discussion on this aircraft I've always assigned 500 pounds of weight increase for turbochargers. They put turbochargers in the XP50 and it used the same wing and virtually the same nacelles.
I've also acknowledged that early turbochargers had issues, actually with the controls not the turbochargers themselves but as you have said they worked those issues out by early 1942.
The F5F used the same 2 engines from beginning to end, they were never upgraded or replaced with the Wright engines used in the F4F-3A which were rated at 1000 hp or 1050 at 13-14000 feet.
I don't believe the F5F ever hit 383 mph either. Top speed in the test was 357 mph at 17,300 feet, at 20,000 feet it's down to 352 mph, the Wrights topped out at 900 hp at 14,000 feet.
Reluctant Poster
Tech Sergeant
- 1,668
- Dec 6, 2006
Turbos only add weight at the altitudes that most naval combat took place at.
In the test the F5F did 346 mph at 14,000 on 1800 hp. With turbochargers you have 2400 hp. 2400/1800=1.3333333. Cube root of 1.3333 is 1.10 x 346 = 380 mph
346 mph to 380 mph at 14,000 would be just fine for carrier ops
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