An early 2-engined carrier based aircraft - worth the effort? (1 Viewer)

[pinsog]

Without some MAJOR weight reduction I am just not seeing this as a viable fighter plane. 1. It is not not stressed for fighter type maneuvers. 2, Both the climb rate and Ceiling to be polite, S**K.
A single R-2600 can suck down over 200 gallons an hour (3.4-3.5 gal min) at Military power or take-off power and around 150 gallons an hour (2.5 gal/min) max continuous. You are going to need 500-600 gallons to get any kind of range.[/QUOTE]

Bringing us back to the F5F. Stressed for fighter combat, 4 .50 machine guns, VERY good rate of climb, weight around 10,000 maybe 11,000 after all the other stuff is added. It would have to perform better than a Wildcat.

 

[oldcrowcv63]

Bringing us back to the F5F. Stressed for fighter combat, 4 .50 machine guns, VERY good rate of climb, weight around 10,000 maybe 11,000 after all the other stuff is added. It would have to perform better than a Wildcat.

Agreed, But would hundreds have been available in late 1941 thru early 1943?

 

[Shortround6]

Weight closer to 12-13,000lbs and rate of climb at 15,000-25,000 starts to become questionable. 10.5 minutes to 20,000ft without guns is hardly setting the world on fire. Granted it is about 2 minutes quicker than an F4F-4 but once you add the guns, ammo, armor and self-sealing tanks?

Beating an F4F isn't the important part, Beating the Zero is.

 

[pinsog]

The Whirlwind was good enough to mix it up with 109's and 190's with 885 hp engines. The F5F could have had 1200 hp Wildcat engines and was the same basic setup. It would have had more drag down low, but would have had 600 more hp to overcome that. Up high with the P&W 1830 WIldcat engine, it should have been able to compete with anything in the world at the time.

 

[Shortround6]

Except there were a shortage of the two stage R-1830 engines during 1941 which required the building of 65 F4F-3A aircraft (competed by Dec 1941) with single stage engines. These engines were also used in the Martlet II III. They had their 1000 hp altitude rating 5,000 ft lower than the two stage engine. For the two stage engines 98 were built in 1940 and 507 in 1941, 275 of them in Oct, Nov and Dec.

Without the two stage engines you have 230hp more than the Whirlwind at 14-15,000ft, not 600 more HP.

The original question in this thread was if ONE plane could do four jobs. It couldn't in 1940-41. You might be able to make a passable fighter OR torpedo bomber/dive bomber but not both. Try slinging a 2200lb torpedo under the F5F and see how far you get. And you can forget about landing back on board with it.

As for UP high?? 2000hp at 19-20,000ft in a twin radial engine plane that weighs 12,000lbs or more? EACH Cyclone has 16.6sq ft of fontanel area, EACH Twin Wasp has 12.6 sq ft of frontal area (not including inter-cooler ducts), Each Peregrine engine had 5.0 sqft not including radiators, Each Allison on an early P-38 had about 6.1 sq ft frontal area. P-38 also had 2300hp at altitudes where the Twin Wasp F5F would have under 2000hp.

Chances of the US building a fighter plane with TWO R-1830 engines and ONLY sticking in four .50 cal guns and a limited amount of ammo are vanishingly small.

 

[pinsog]

For certain it couldn't do four jobs. The only job I would have asked of the F5F would be fighter/intercepter.

You obviously know more about the subject than me. Comparing the F5F to the Whirlwind, frontal square footage of engines vs hp. The Whirlwind would have about half the frontal area with 885 hp per engine vs 1200 per engine on the F5F. How would that equate to speed at sea level? Best guess on F5F top speed at sea level?

 

[Glider]

Bringing us back to the F5F. Stressed for fighter combat, 4 .50 machine guns, VERY good rate of climb, weight around 10,000 maybe 11,000 after all the other stuff is added. It would have to perform better than a Wildcat.

I know I must be having a senior moment but I don't get this. According to the data sheet provided the X5F-1 weighs 10,892lb as an overload weight which is normal weight with an extra 100 gallons. That excludes the guns, ammo, armour, self sealing fuel tanks and other assorted equipment needed for combat.

Assuming that you keep to the overload weight as a max you are going to lose a lot of fuel as I am confident the extras listed above will come to more than 800lb. As for this fast climb statements its time to 10,000 ft is exactly the same as the Beaufighter VI which never claimed to be a good climber. If and I admit in my mind its a big if, it did have a sweet spot where it climbed at 4,000 ft/min for a minute, it must have crawled the rest of the time at an average of about 1,800 ft/min.

To say that its better than a Wildcat I also don't get. The F4F3 time to 10,000 ft is 3.5 min (compared to 4.6 min) and to 20,000 ft 7.6 min (compared to 10.5 min). From what I can see the Wildcat F4F3 was a much better performer. The F4F4 was a poor performer I will agree, even the much maligned Beaufighter could leave it behind in a climb.

 

[pattle]

Looking at the 'Shattered sword', at the pg. 547 is written that 'torpedoes could not be brought back aboard the ship once their plane was launched', source for this being being Michael Wenger. I assume this is only for the IJN?
Wonder whether anybody knows if the RN requirement was to bring back an un-expended torpedo?

Yes the Swordfish could land carrying an un-expended torpedo, but not an expended one. I have read of Swordfishes returning from a patrol or aborted sortie carrying a torpedo and landing with it, but I would expect that it would depend on the condition of the sea. The Royal Navy was very concerned at the cost of torpedos.

 

[pinsog]

I know I must be having a senior moment but I don't get this. According to the data sheet provided the X5F-1 weighs 10,892lb as an overload weight which is normal weight with an extra 100 gallons. That excludes the guns, ammo, armour, self sealing fuel tanks and other assorted equipment needed for combat.

Assuming that you keep to the overload weight as a max you are going to lose a lot of fuel as I am confident the extras listed above will come to more than 800lb. As for this fast climb statements its time to 10,000 ft is exactly the same as the Beaufighter VI which never claimed to be a good climber. If and I admit in my mind its a big if, it did have a sweet spot where it climbed at 4,000 ft/min for a minute, it must have crawled the rest of the time at an average of about 1,800 ft/min.

To say that its better than a Wildcat I also don't get. The F4F3 time to 10,000 ft is 3.5 min (compared to 4.6 min) and to 20,000 ft 7.6 min (compared to 10.5 min). From what I can see the Wildcat F4F3 was a much better performer. The F4F4 was a poor performer I will agree, even the much maligned Beaufighter could leave it behind in a climb.

I was quoting weight from memory. I should look next time before I type. On prototypes, do they generally ballast for weapons weight when testing? I know the performance up high would be lower with the Wright 1820's, which is why I suggested switching to the P&W 1830's that the Wildcat used.

What stats do you list for the F5F? Info is a bit hard to come by.

2400 hp for 11,000 to 12,000 pounds doesnt seem too bad to me. It would be considerably lighter than a P38, more reliable, and I would think would outclimb a P38, at least the early models.

 

[Shortround6]

You have to rather careful when comparing power, you keep saying 200 to 2400hp which the F5F might have had a sea level. Once you start to climb things fell off rather badly for the radial engine fighters. The Early P-38 had 2300hp for take-off and a 5 minute rating of 2300hp anywhere from sea level to almost 25,000ft (it was supposed to be 25,000ft but the early turbos and inter-coolers didn't work quite as advertised.) An F5F using later Cyclones might have had 2400hp at take-off and up to around 4100-5000ft and 2000hp at 14-15,000ft and around 1720hp at 20,000ft and getting even worse by 25,000ft. It has been mentioned before that the P&W engines were over 200lbs heavier each than the Cyclones and are longer.

You also have to be careful comparing rates of climb as the US "standard" early in the war was to use Military power for the first 5 minutes of the climb and then change to max continuous power for the remainder of the climb. so if plane X climbed to 20,000ft in 10 minutes it use military for the first 5 minutes and max continuous power for the last 5 minutes which makes it altitude performance look a bit worse than it actually was.

As far as ballasting goes, sometimes it was done and sometimes not. It depends what the flight tests were trying to achieve. And using ballast does NOT simulate the drag of protruding barrels, cartridge ejection slots and a few other things.

A few of the things the XF5F-1 had problems with was engine overheating and excessive drag. Part of the drag problem was due to the landing gear doors and may have been solvable but cooling problems usually required more drag to solve than less drag

 

[Glider]

tomorrow Paul kindly supplied the info in his posting 48

 

[tomo pauk]

Who is 'tomorrow Paul'?

 

[Glider]

God only knows, it was meant to be Tomo pauk. Maybe he has friends in very, very high places.

Apologies one and all

 

[Shortround6]

As a check on the amount of fuel required/needed for certain missions the TBM-3 Avenger carried 325 US gallons carried between 3 tanks in the center section. Two types of bomb bay tanks were available, either a 212US gallon self sealing (non drop-able) or a 270/275 gallon non-self sealing (but drop-able) and under wing drop tanks could be used of either 58 or 100 gallons capacity. The bomb bay could house not only a torpedo but twelve 100lb bombs, four 500lb bombs, two 1000lb AP bombs side by side, two 1000lb GP bombs in tandem, a single 1600lb AP bomb or a single 2000lb GP bomb. Note it might be possible to carry 2000lb worth of bombs AND 525 gallons if the larger under wing drop tanks are used or 441 gallons if the smaller are used.

The Earlier versions operated at lower weights but it was possible for an Avenger to carry about 2000lbs of bombs and 199 gal of fuel and weigh around 15,000lbs or 1000lb of bombs and 301 gallons of fuel. Fuel and 301 gallons could be carried by going to around 15775lbs.

The engine installation for an F4F with a two stage R-1830 was about 2465lbs not including the fuel system, or 4930lbs for two. Weight of the engine installation in a YP-38 was about 5525lbs not including fuel system (and maybe wing leading edge inter-coolers.)

The Liquied cooled engines were NOT responsible for 2-3000lb of extra aircraft weight.

 

[tomo pauk]

No need to apologize, Glider. I've had a good laugh
Unfortunately, I don't have friends in high places.

 

[davparlr]

It would also take some or all carriers out of action for a number of weeks if not a few months each (can be done in rotation so only one or two are out of service at once) in order to upgrade the elevators and landing systems ( and you have done nothing for the catapult/s).

As usual, I appreciate your thoughtful and knowledgeable comments. I really didn't think about the catapults! My concept was based on the purchase of the DB7A by France. The order was placed in October, 1939. If this had been a Navy contract (too bad for the French), I think they would have had plenty of time, two years, to upgrade the carriers as required prior to Pearl Harbor.

You have two A-20 "prototypes"

The R-1830 powered version and the R-2600 powered version

The R-1830 versions may actually "fit" better being only 15' 10" high at the tail and weighing around 12,000lb empty depending on exact model. data form Joe Baughers web site.

For example French spec DB-7;

The DB-7 certainly would have been a better match on weight and landing speed and was faster at SL than the Zero and close at altitude, however I felt I would like a better advantage in speed and that would take the R-2600.

This is without self sealing tanks, no armor and a few things that are not quite right.

Not all of the 1941 Navy aircraft had armor or self-sealing tanks. Certainly the F4F-3 did not start upgrading until the end of the year. The TBD-1s probably did not, but I don't know. The SBD-3s did have self-sealing tanks and maybe armor. In any event, these needed to be included.

Like while the contract called for a landing speed of 81mph actual flight testing resulted in the landing speed being 88mph. About an 18% increase in energy needing to be absorbed in the carrier arresting system.

However, with a 20kt wind down the deck, this is still higher than Navy plane, but mitigated. Also, a recommended larger wing would also mitigate approach/landing speed, but lose a bit of top speed.

Going to the R-2600 gives you a couple of choices. You now have the power and speed but you have more weight, a higher tail fin (17' 7") that you may be able to trim/fold or extend in cord to reduce height?

I may be at sea on this but wikepedia states that the minimum hanger deck height of the Lexington was 21 ft. I don't have any other carrier vertical dimensions.

The Early R-2600 powered aircraft kept weight down by keeping the original fuel tanks (325 gallons max and 205 gallons "normal") which resulted in 1/2 the range of the R-1830 powered aircraft.

For a combat radius of 400 miles I would guess a combat range of 650 miles (?).

Height may be wrong.

That's what I have.

Please note 2200lb empty weight increase. Getting a landing weight even close to 15-16,000lbs is going to be VERY difficult once you add 400lbs crew, guns, radio, oil and even minimal oil and fuel.

Definitely a challenge. But carrier mods must accommodate expected aircraft performance.

BTW, 2nd DB-7A with R-2600 was first flown Oct 10th 1940 but it took until late November to fix cooling problems with the engine.

100 were accepted by February, 1941

By early 1941 you are into the A20-C model:

Very impressive aircraft but I still would eliminate defensive fire power.

Without some MAJOR weight reduction I am just not seeing this as a viable fighter plane. 1. It is not not stressed for fighter type maneuvers. 2, Both the climb rate and Ceiling to be polite, S**K.
A single R-2600 can suck down over 200 gallons an hour (3.4-3.5 gal min) at Military power or take-off power and around 150 gallons an hour (2.5 gal/min) max continuous. You are going to need 500-600 gallons to get any kind of range.

This is not a recommendation for a fighter type aircraft but a replacement for the TBD/TBF and SBD/SB-2C. At this time period, or maybe any time in WW2, I don't think a twin engine Navy fighter can justified its expense, except as a night fighter, whereas a fast twin engined bomber could possibly be effective enough to justify its presence. For a low altitude bomber, maybe 10 minutes, or 25 gallons, at max continuous power?

 

[Shortround6]

To get an idea of what the Navy was thinking when they bought the F5F idea in the beginning:

http://www.alternatewars.com/SAC/SD...cation_for_XF5F-1_(Excerpts)_-_5_May_1938.htm

and a short but useful history of the project;

http://www.alternatewars.com/SAC/Notes_on_the_History_of_the_XF5F-1.htm

I would note that the power quoted in the first link " The horsepower for 2 Pratt and Whitney R-1535-2 engines is estimated to be 1500 from sea level to 17,500 feet altitude at 2550 RPM with 3-blade propeller. For take-off the 2 engines are rated at 1650 HP at 2630 RPM." is for BOTH engines and not the power per engine.
The two stage R-1535 engines may never have flown in ANY plane (test beds) having been dropped, as the Navy feared, from development. Production of 2 stage R-1830s was 4 engines in May of 1940, 1 in June, 1 in July, 11 in August with a total of 98 engines for all of 1940. Use of the R-1820s was just to get a test airplane into the air to check calculated performance.

Also please note that the empty weight of the plane grew by about 1500lbs from initial specifications/calculations to the prototype powered with the Wright Cyclones.

 

[Shortround6]

As usual, I appreciate your thoughtful and knowledgeable comments. I really didn't think about the catapults! My concept was based on the purchase of the DB7A by France. The order was placed in October, 1939. If this had been a Navy contract (too bad for the French), I think they would have had plenty of time, two years, to upgrade the carriers as required prior to Pearl Harbor.

Thank you for the complement, I believe much more can be accomplished ( or facts brought out) by polite disagreement than name calling.

AS was posted earlier (Post #230

American carrier dimensions:

Hanger deck clear heights:
Lexington Class: 20'
Ranger: 18' 11"
Enterprise Class: 17' 3"
Wasp: 17' 2"
Essex Class: 17' 6"

Elevators; dimensions x lift capacity:
Lexington: 29' 2¼' x 34' 10¼" 6,000 lbs
Ranger: 51' 10¼" x 41' 0¼" 15,000 lbs
Enterprise: 48' x 44' 17,000 lbs
Wasp: 48' x 44' 17,000 lbs
Essex: 48' x 44' 28,000 lbs

Now the Lex and Saratoga may very well have been refitted with newer, larger elevators before the war. Or at least the forward one changed. All seven (not counting Langley) early war carriers could fit the R-1830 powered DB-7 height wise but 4 of them would require a bit of a trim ( a few inches ?) for the R-2600 powered versions.

While it is true that few Navy planes had armor or self sealing tanks in 1941 or for most of 1941 that is not true of 1942 when actual combat was joined. The situation had flipped and with every month a larger percentage of planes had armor and self sealing tanks. Projections of combat effectiveness have to take this into account. Many accounts speak of the loss of performance of both the Buffalo and Wildcat as these necessary improvements were made. But you have already stated this.

The Navy had just changed the required stall speed from 62-66mph to 70 mph in the 1938-39 program aircraft, While they might accept minor variations (72-76mph?) asking them to go to 85-90mph may be too much at this time. What they would find acceptable in 1943/44 is another story even on the same basic sized carriers. I guess it depends on how far you push a "what if" as in "what if" the Navy and company XX did such and such in 1939/40 while trying to meet current requirements or "what if" the Navy and company XX did so and so but relaxed certain requirements to what was acceptable near the end of the war 2-4 years sooner.

I would note that "as built" the best place to fold the wing on an A-20 was at a break 5 feet out board of the engine nacelle. This was an existing joint in the wing and the outer wing/s were often detached for transport by ship. This allows for easy prop clearance on the elevator but means you need an elevator around 32-33 feet wide, which seems to have been meet but does leave you with a sizable parking area. It might be possible to move the hinge point inboard several feet but that means e-engineering that area of wing/flaps in addition to engineering the hinge.

This is not a recommendation for a fighter type aircraft but a replacement for the TBD/TBF and SBD/SB-2C. At this time period, or maybe any time in WW2, I don't think a twin engine Navy fighter can justified its expense, except as a night fighter, whereas a fast twin engined bomber could possibly be effective enough to justify its presence. For a low altitude bomber, maybe 10 minutes, or 25 gallons, at max continuous power?

At max continuous power the TWO engines on an A-20 were sucking around 5 gallons a minute anywhere from 6,000-15,000ft. That is the one hour (or longer) rating. Military power could add another gallon per minute per engine or a bit more (7+ gallons a minute).

http://zenoswarbirdvideos.com/Images/A20/A20FOICa.pdf

 

[davparlr]

Now the Lex and Saratoga may very well have been refitted with newer, larger elevators before the war. Or at least the forward one changed. All seven (not counting Langley) early war carriers could fit the R-1830 powered DB-7 height wise but 4 of them would require a bit of a trim ( a few inches ?) for the R-2600 powered versions.

You are right on the height. Wikipedia does state that the Lexington had two elevators, the forward one was 30'x60' with a capacity of 16,000 lbs, the aft one was 30'x36' with a capacity of 6,000 lbs. Some model pixs shows the forward elevator much wider than the aft elevator. The ship had a couple of refits before the war but I could not trace them down.

The Navy had just changed the required stall speed from 62-66mph to 70 mph in the 1938-39 program aircraft, While they might accept minor variations (72-76mph?) asking them to go to 85-90mph may be too much at this time. What they would find acceptable in 1943/44 is another story even on the same basic sized carriers. I guess it depends on how far you push a "what if" as in "what if" the Navy and company XX did such and such in 1939/40 while trying to meet current requirements or "what if" the Navy and company XX did so and so but relaxed certain requirements to what was acceptable near the end of the war 2-4 years sooner.

In my mind there are a couple of situations for addressing "what ifs", one is what is technically feasable, eg., knowledge base was sufficient, material was available, engines could be built, etc., and the other is what is realistically feasable, e.g., programmatics are considered like engines may have been built but were not available due to previous use. In this case, technically, I believe a fast twin engine bomber could have been built that would have been the most powerful carrier aircraft in the world in 1941-2, but, realistically it could never happen. Both the Navy and AAF, which was faced with a similar issue with the B-26 and didn't know how to deal with it, were for the most part right out of biplanes and had a biplane mentality. I am sure that when the Navy looked at the A-20 they quickly dismissed this Army bomber as too big and too heavy and landed too fast without really thinking what it could do. And besides, I am sure they thought that what they had could handle the enemy.

I would note that "as built" the best place to fold the wing on an A-20 was at a break 5 feet out board of the engine nacelle. This was an existing joint in the wing and the outer wing/s were often detached for transport by ship. This allows for easy prop clearance on the elevator but means you need an elevator around 32-33 feet wide, which seems to have been meet but does leave you with a sizable parking area. It might be possible to move the hinge point inboard several feet but that means e-engineering that area of wing/flaps in addition to engineering the hinge.

If built from the ground up as a Naval bomber, these issued could be addressed during design. However, the 5' outboard may be required anyway to allow wing folded aircraft down in the hanger, unless, of course, they use a Grumman F6F type fold design.

 

[Shortround6]

In this case, technically, I believe a fast twin engine bomber could have been built that would have been the most powerful carrier aircraft in the world in 1941-2, but, realistically it could never happen. Both the Navy and AAF, which was faced with a similar issue with the B-26 and didn't know how to deal with it, were for the most part right out of biplanes and had a biplane mentality. I am sure that when the Navy looked at the A-20 they quickly dismissed this Army bomber as too big and too heavy and landed too fast without really thinking what it could do. And besides, I am sure they thought that what they had could handle the enemy.

They weren't sitting on the status quo in 1938-39-40. The requirement that lead to the Curtiss SB2C was issued in August of 1938. The Navy only ordered a few replacement TBD Devastators to make up for attrition (crashes) as they knew they wanted something better. and considering in 1935-36 the Devestator "It was the first widely used carrier-based monoplane as well as the first all-metal naval aircraft, the first with a totally-enclosed cockpit, the first with power-actuated (hydraulically) folding wings;" and the Navy was looking to replace it 1938-39 doesn't seem like "biplane mentality" to me. The requirement for the Avenger was issued in 1939 after the Navy thought about what they wanted. And a top speed of 300mph and a ceiling of 30,000ft hardly seem like "biplane mentality" either. Granted they did not get all they that wanted (they didn't even get the 17ft width dimension with wings folded they wanted) but it is doubtful that a navalized DB7 would have given them the speed, altitude and range they originally requested either. Perhaps 2 out of 3

The Navy had also suffered a number of crashes With the Northrop/Douglas BT-1 Dive bomber due to poor low speed handling which pretty much solved by the modified Douglas SBD. The BT-1 first flew in 1936 and was going into service in 1938 about hte time the requirement that lead to the SB2C was issued. The Dauntless was NOT built to that specification but was a "fill in" aircraft while the "new" generation was being worked on.

There were so few Devastators available I am not sure that all 7 active carriers ( counting Ranger but not Langley) even had a full squadron of torpedo bombers.

The Navy was very conscious of handling and accidents because they could seriously degrade a Carriers operational capability in just a few weeks in a combat zone. With dozens of cap and search flights being put up every day that weather allowed flying at all even an accident rate of 2% could cut into combat strength in just a couple of weeks. ( one reason for those planes/parts hanging from the hanger ceiling).

If built from the ground up as a Naval bomber, these issued could be addressed during design. However, the 5' outboard may be required anyway to allow wing folded aircraft down in the hanger, unless, of course, they use a Grumman F6F type fold design.

It is actually the Avenger type fold.

Avenger prototypes used it before the F4F-4 Wildcat did.

Technically the twin engine scout/torpedo plane may be possible and it may be possible a year or more before the Avenger shows up. Wither on the whole, it would have been as useful or as effective (given the space requirements to store) as a greater numbero f Avengers may be subject to question.