Thank you. All that makes sense. Answered my questions. As usual and like most other things there is never a straight simple answer, everything is a balance based on dozens and dozens of other factors. I'm out and about so if I think of any I'll ask later.
Why was the SBD such an effective aircraft?
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Thank you. All that makes sense. Answered my questions. As usual and like most other things there is never a straight simple answer, everything is a balance based on dozens and dozens of other factors. I'm out and about so if I think of any I'll ask later.
Yup, and if you don't believe it, try flying the dang thing at night in the soup, dodging thunderstorms, lit up by St Elmo, a cabin full of panicky passengers, and destination and alternate below minimums.
Y'all have fun now, hear?
Wes
Kevin J
Banned
Nice plane, good performance, similar to Whirlwind. Perhaps like the Whirlwind was twice the price of a Spitfire, the Skyrocket was twice the price of a Wildcat? Like the Whirlwind, unless you change the engine, it has limited development potential. It requires extra training as its a twin. War is just around the corner in 1941 when perhaps production could have been authorised. The Corsair is a similar size,not a twin, an engine with development potential and faster in both level flight and the dive, Skyrocket only does 450 mph so not that good. The F4F-4 can dive 65 mph faster, so go with the F4F-4, start development on the F6F and modify the Corsair to production standard. The Skyrocket is a dead end just like the Whirlwind.
I thought the problem with the Whirlwind was mainly range? Altitude performance wasn't as crucial in the Pacific as in the BoB, and the F5F had a pretty impressive range of 1200 miles at least per the wiki. The extraordinary climb rate would probably be particularly useful for a carrier fighter, the typical problem of taking off and needing to climb to altitude, or chasing torpedo bombers when the alert for the dive bombers comes out could be far better alleviated with a fast climbing plane. Especially since the F4F was such a slow climber.
Twin engines requiring more training though is definitely a valid point, as is (to a lesser extent) the added expense of the second engine. For the US the bigger issue was probably training time since there was a bit of a bottleneck early on and carrier pilots already had a lot to learn.
Twin engines requiring more training though is definitely a valid point, as is (to a lesser extent) the added expense of the second engine. For the US the bigger issue was probably training time since there was a bit of a bottleneck early on and carrier pilots already had a lot to learn.
- Thread starter
- #285
The Navy is a pretty tradition bound outfit, so Adm Towers would be most likely not to go with a twin. The heavy fighters such as the Bf 110 didn't do so well, though the F5F is more like a proto Tigercat. He didn't want to be hung out to dry for a possible failure of a new idea.
Actually the F5F was dived vertically at 505 mph on February 1, 1941. The F4U-1 when it first appeared would do 312 mph, exactly the same as the F5F. The F5F engines were only rated at 1000 hp from SL-4500 feet and 900 hp from 7300-14000 feet. The G205, a non-turbo 2 speed engine used in the Wildcat, was rated 1200 hp from SL-4200 and 1000 hp at 14000. Using the cube rule that would boost the top speed of the F5F from 312 to 331mph. The F4F-4 Wildcat did 275 mph at SL. So the F5F would be 35 mph faster at SL with original engines and be 56 mph faster at SL with slightly upgraded engines that were available in 1940. If you want to add turbochargers to the F5F, top speed at 20000 feet goes from 352 on about 750 hp per engine to 411 mph on 1200 hp per engine, the corsair at 20,000 feet would do 378 mph. With current engines in 1940, the F5F was equal or faster than the Corsair that appeared in 1943. With turbochargers on the F5F the Corsair is slower, substantially slower and getting worse with altitude. By the time the Corsair came out in 1943, the F5F could start using 1350 hp Wright Cyclones from the FM2 giving it 2700 hp giving it a SL top speed of 344 mph. If you added water injection to that engine you get 1480 hp per engine with a total of 2960 hp giving the F5F a top speed of 355 mph at SL.
F5F Skyrocket wasn't a dead end, I think it could have been a game changer available in 1940 when the Wildcat became available if Grumman had focused on it instead of the Wildcat, but Grumman and the US navy went the safe route instead of rolling the dice.
Range: The F5F had 278 gallons in a large tank between the engines. adding outer wing tanks of 65 gallons each like the early Corsair had, or like the Whirlwind had would have put it at 400 gallons internal. As large as the folding wings were on the F5F, I would say they could have put much larger tanks in them if they wanted. 2400 hp from turbochargers would offset the weight and besides, you would burn all of that fuel off in the warmup, take off, climb and cruising to the enemy so they would be empty when the fight started. This doesn't count what it should be able to carry in drop tanks. It had the same square feet of wing as the Corsair, 303 square feet, and had 400 more hp at take off then the early Corsair so it should have been a weight lifter as well
Essentially a turbocharged F5F would have the same performance as an early P38 in speed, but it is 10 feet shorter and 10 feet less wingspan so it should be MUCH more maneuverable and it would have weighed 2000-3000 pounds less depending on how it was set up on fuel so it should substantially out climb a P38
USA didn't care about price. We built carriers a dime a dozen, the B29, the P47, the P38 and the atomic bomb. And how many F5F's with 2 engines and turbochargers could have been built for the price of replacing the Lexington, Yorktown and Hornet?
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michael rauls
Tech Sergeant
- 1,679
- Jul 15, 2016
For better or worse I think that's the dynamic that makes it so hard to get new ideas, aviation or otherwise, off the ground.
I can also understand a bit of apprehension when trying to jump from a Grumman F3F biplane to a, when I'm done with it, 12,750-13,000 pound twin engine, turbocharged, 400 gallon of fuel F5F.
Clayton Magnet
Staff Sergeant
- 903
- Feb 16, 2013
The Whirlwind was operational 2 years before the XF5F MIGHT have been. Strip the armour, self sealing tanks, cannons+ammunition, wartime paint and other operational items out of the Whirlwind, and you would have a different animal. As far as I know, the XF5F never flew with a full operational load out, so its performance numbers in comparison to operational types needs to be taken in context.
Kevin J
Banned
Rolls-Royce mod'ed a Whirlwind and put the radiators under the engines, it was 24 mph faster at sea level. That would free up space where the wing leading edge radiators were for extra fuel tanks. Whirlwind range was as per Kittyhawk so good, except for price of 2 x Spitfire, not so good. My guess would be 1200 mile range without drop tanks unlike F5F which was same as Wildcat with / without drop tanks.
The XF5F was unarmed but I believe it was ballasted for weapons. It did have a radio installed.
Empty weight 7990.
Normal Loaded weight 10,021 leaves 2,031 pounds for load.
178 gallons of fuel is 1,068 pounds. 150 pounds of oil (P36 oil times 2) 200 pound pilot. Leaves 613 pounds for weapons.
4 50's is 300 pounds. 300 rounds per gun is 300 more pounds.
Empty weight 7990. Overload weight 10,892 leaving 2902 for load.
277 gas is 1662.
150 pounds of oil.
200 pound pilot.
Leaves 890 pounds for weapons.
4 50's is 300 pounds. 500 rounds per gun is 500 pounds.
Based on this, I think it was ballasted for weapons.
It was painted. In all of my previous posts I added 150 pounds of armor and 200 pounds for self sealing the fuel tank
10892 add 150 for armor and 200 for seal sealing tank
Go ahead and change the engines out from the 1820 G205 the Wildcat used and you have 2400 hp up to 4200 ft and 2000 hp at 14000
2400 hp at SL using cube rule brings SL speed up to 331.
Speed at 4500 feet jumps from 326 to 346
Speed at 14000 feet jumps from 346 to 367
11,250 pounds ready to fight including armor and self sealing tanks
Kevin J
Banned
Me too, I'm a fan. It just needs a decent engine, unfortunately the only one available is the Hispano-Suiza 12Y or Z and its not available to us.
Those are 80 gallon tanks in the Whirlwind wings. Those wings are much smaller than the F5F wings. You could easily add 80 gallon tanks per side on the F5F, add that to the 278 it already carried and you have a lot of fuel. Turbocharge the engines to make up for weight gain and you have a 2400 hp plane that still weighs 1500 pounds less than a P38 with 300 gallons and it's carrier capable.
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Drag is always brought up on the F5F because well, the windmills they used for engines.
Look at the F5F test in post 245.
The F5F does 352 mph at 20,000 feet.
The engines can only put out 900 hp at 14,000 so those engines are down to what, maybe 750 hp each?
From wwiiperformance P38E
20,000 feet 393 mph 3000 rpm 1150 hp
20,000 feet 386.5 mph 2600 rpm 1000 hp
20,000 feet 352.5 mph 2280 rpm 750 hp
Notice a P38E is doing 352 mph at 20,000 feet on 750 hp the same speed the F5F does on, I think, about the same power.
The P38E does 340 mph at 5000 feet on 1150 hp per engine 2300 total
The F5F does 326 mph at 4500 feet on 1000 hp per engine 2000 total
Hmmm. Cube rule, lets take an F5F at 1150 hp 2300 total divide by 2000 = 1.15 cube root is 1.047689 times 326 mph equals 341.54 miles per hour.
So apparently a P38E and an F5F have approximately the same drag. Could some of you guys look at this data and see if I am looking at this correctly?
Look at the F5F test in post 245.
The F5F does 352 mph at 20,000 feet.
The engines can only put out 900 hp at 14,000 so those engines are down to what, maybe 750 hp each?
From wwiiperformance P38E
20,000 feet 393 mph 3000 rpm 1150 hp
20,000 feet 386.5 mph 2600 rpm 1000 hp
20,000 feet 352.5 mph 2280 rpm 750 hp
Notice a P38E is doing 352 mph at 20,000 feet on 750 hp the same speed the F5F does on, I think, about the same power.
The P38E does 340 mph at 5000 feet on 1150 hp per engine 2300 total
The F5F does 326 mph at 4500 feet on 1000 hp per engine 2000 total
Hmmm. Cube rule, lets take an F5F at 1150 hp 2300 total divide by 2000 = 1.15 cube root is 1.047689 times 326 mph equals 341.54 miles per hour.
So apparently a P38E and an F5F have approximately the same drag. Could some of you guys look at this data and see if I am looking at this correctly?
Wildcat
Major
I agree, all dive bombers were vulnerable to enemy fighters. The RAAF never lost a vengeance to enemy a/c. The vengeance was still useful in 43-44, if you look at the missions the RAAF was using them for in New Guinea they were perfectly suitable for the task. They were flying CAS and targeting enemy troop positions often located on ridge lines and in mountainous terrain. Often the target would be indicated with smoke either from army mortars or Boomerangs. Precision was crucial here and I'd argue dedicated dive bomber were more accurate then fighter-bombers in these situations. It must be noted though that RAAF vengeances were operating under total allied air superiority.
Kevin J
Banned
Whirlwind had 134 Imp gal plus either 45 or 90 gal drop tanks.
swampyankee
Chief Master Sergeant
- 4,031
- Jun 25, 2013
The TBF, in British service, couldn't carry British torpedoes, so it's not improbable that a B-26 couldn't either.
swampyankee
Chief Master Sergeant
- 4,031
- Jun 25, 2013
Duplicate.
MIflyer
1st Lieutenant
In the case of the Ercoupe the twin fins/rudders were designed to move those control surfaces out of the propwash and therefore reduce the P-factor that can induce spins and cause a need for additional rudder in power-on lo speed circumstances.
Later the center section of the elevator was cut out to reduce the effects of propwash. Combined with a spring that came into effect in extreme up-elevator situations that enabled the airplane to be loaded to higher gross weights by making it much more difficult to pull too many G's. The C model was the first Ercoupe certified but when the heavier D model came out they reduced the elevator travel to reducemax G loads, making stalled landings difficult if not impossible; this was unpopular.
Later the center section of the elevator was cut out to reduce the effects of propwash. Combined with a spring that came into effect in extreme up-elevator situations that enabled the airplane to be loaded to higher gross weights by making it much more difficult to pull too many G's. The C model was the first Ercoupe certified but when the heavier D model came out they reduced the elevator travel to reducemax G loads, making stalled landings difficult if not impossible; this was unpopular.
