1941: the best case for 350+ mph CV fighters?

[The Basket]

Why do you need 350mph naval fighters? In 1941?
For the Fleet Air Arm speed was less important as you were likely to encounter slow reconnaissance aircraft. Range was vital simply to get back to the carrier safely. Not for missions. It takes time to recover or launch aircraft and the carrier maybe miles away from where you left it. Also 2 seater was specified so you can have a navigator for over water flights. The Fairey Fulmar didn't do 350mph and started its service in 1941. The Fulmar had to carry fuel and that 2nd crewman so 350mph was not going to happen. But the Swordfish couldn't do 350mph either and neither could the Ar-196. So certainly where the FAA was concerned a navy Spitfire was not a peacetime need.

 

[wuzak]

What's the diff? Frontal area of the 1535 was so close to the 1830 as to be practically insignificant. The 1820, on the other hand, was a barn door, besides being a boneshaker. I've ridden behind both 1820 and 1830. I'll take a Pratt any day.
Cheers
Wes

The R-1535 was ~4" smaller in diameter than the R-1830 - 44.15" to 48.03".

In frontal area that is 1,530.9sq.in for the R-1535 and 1,811.8sq.in for the R-1830. That is just over 18% more frontal area for the R-1830.

 

[wuzak]

Why do you need 350mph naval fighters? In 1941?
For the Fleet Air Arm speed was less important as you were likely to encounter slow reconnaissance aircraft.

What about carrier defence operations? Maybe speed is not a requirement, but climb more than likely was?

 

[wuzak]

The Fairey Fulmar didn't do 350mph and started its service in 1941. The Fulmar had to carry fuel and that 2nd crewman so 350mph was not going to happen. But the Swordfish couldn't do 350mph either and neither could the Ar-196. So certainly where the FAA was concerned a navy Spitfire was not a peacetime need.

Weren't the FAA looking at a navalised Spitfire from 1938/1939?

They also had looked at a navalised Hurricane, but noted that the performance advantage the Hurricane held over the Ju 88, a likely opponent for fleet fighters, was marginal - when the naval equipment was added it was expected that margin would be non-existent.

 

[wuzak]

It has been suggested to me that the P.1009 Typhoon Fleet Fighter to N.11/40, basically a navalised Typhoon, may have been a possibility.

I would think that such an aircraft would completely miss the 1941 service target.

 

[The Basket]

The FAA was part of the RAF in 1938 so are the RAF going to give up it's Spitfires?

 

[Elvis]

...CV meaning 'carrier vessel'.
Basically - how would've looked a speedy carrier-borne fighter for each country with CVs, whether the carriers are in service or in pipeline. Best case, but still plausible (no non-historical engines or arodynamic properties), with acceptable low-speed characteristics, plus the weapon and protection suite as used on the fighters of respective air services/forces in 1941. With useful range/radius.

For part of that year it would've been the Brewster Buffalo.
It beat out the Xf4F during trials and even the pilots who flew in those trials said that it was the better handling plane.
That first generation of Brewster fighters were ok, if not a little slow (I believe neither the Grumman nor the Brewster could achieve 350 mph, but it was what we had at the time).
It was the versions that came later on that ultimately led to the plane's demise.
Otherwise, the only other plane I can think of, off-hand, for Naval use, that would've been considered "speedy" might have been the Corsair.
Pretty sure it was in service in '41.


Elvis

 

[XBe02Drvr]

The R-1535 was ~4" smaller in diameter than the R-1830 - 44.15" to 48.03".

In frontal area that is 1,530.9sq.in for the R-1535 and 1,811.8sq.in for the R-1830. That is just over 18% more frontal area for the R-1830.

We're talking twin row radials here. There's more to total engine/cowling drag (the pertinent parameter) than simple frontal area. I suggest the drag difference of a pair of 4 inch larger (4 foot diameter) engines would be pretty darn small compared to a pair of 1820 drag queens. We tore down, built up, and ran an 1820 at mech school. It's a veritable barn door. I'm 6' 5", and with the engine on its stand, (it had a short "club" prop) I could just reach a top cylinder sparkplug and had to get down on the floor for a bottom cylinder.
Cheers
Wes

 

[wuzak]

We're talking twin row radials here. There's more to total engine/cowling drag (the pertinent parameter) than simple frontal area. I suggest the drag difference of a pair of 4 inch larger (4 foot diameter) engines would be pretty darn small compared to a pair of 1820 drag queens. We tore down, built up, and ran an 1820 at mech school. It's a veritable barn door. I'm 6' 5", and with the engine on its stand, (it had a short "club" prop) I could just reach a top cylinder sparkplug and had to get down on the floor for a bottom cylinder.
Cheers
Wes

The R-1820 is only 4-5" larger in diameter than the R-1830.

 

[Shortround6]

What's the diff? Frontal area of the 1535 was so close to the 1830 as to be practically insignificant. The 1820, on the other hand, was a barn door, besides being a boneshaker.

Frontal area of the R-1535 was about 10.5 sq ft, frontal area of the R-1830 was about 12.6 sq ft. Depending on the plane that may mean little difference (airliner or bomber with large fuselage and wing, size of engine nacelles is small portion of the total) or it may be a large difference, On the F5F the small nacelle may be roughly the size of the fuselage and the wing is smaller than the wing on an F4U.
BTW the frontal area of an R-2800 is 14.8 sq ft. A Cyclone 9 is about 16.6 sq ft.
A twin needs a crap load more power than a single to hit the same speeds.

 

[pinsog]

Frontal area of the R-1535 was about 10.5 sq ft, frontal area of the R-1830 was about 12.6 sq ft. Depending on the plane that may mean little difference (airliner or bomber with large fuselage and wing, size of engine nacelles is small portion of the total) or it may be a large difference, On the F5F the small nacelle may be roughly the size of the fuselage and the wing is smaller than the wing on an F4U.
BTW the frontal area of an R-2800 is 14.8 sq ft. A Cyclone 9 is about 16.6 sq ft.
A twin needs a crap load more power than a single to hit the same speeds.

The XF5F Skyrocket would have had a crap load more power. Hellcat had 1650 hp at 25,000 feet. A Skyrocket with turbo P&W 1830's would have had 2,400 hp at 25,000 feet in 1941. Should weigh about the same after you add 4 50's, ammo. armor and self sealing tanks.

Everyone keeps talking about the terrible drag on the XF5F, but could someone please explain why the Skyrocket and the Hellcat go virtually the same speed on the same horsepower?

Hellcat SL 310 mph 1890 hp
14,000 350 mph 1800 hp
17,000 362 mph 1800hp

Skyrocket SL 311 mph Not sure if its on 2,000 or 2,400 hp
14,000 346 mph 1,800 hp
17,300 356 mph Less than 1,800

Above 17,300 the Skyrocket performance drops off because the 'barn doors' (Wright 1820) are only rated for 900 hp up to 14,000.

 

[wuzak]

Where is your XF5F data coming from?

 

[pinsog]

http://alternatewars.com/SAC/XF5F-1_and_XFL-1_PD_-_26_December_1942.pdf

Notice at the bottom, actually top of the 2nd page "performance based on flight tests"

 

[wuzak]

http://alternatewars.com/SAC/XF5F-1_and_XFL-1_PD_-_26_December_1942.pdf

Notice at the bottom, actually top of the 2nd page "performance based on flight tests"

I found the data in this post by Tomo.

The XF5F is tested as capable for 357-358 mph at 17300 ft, no guns, no ammo.

Presumably no armour as well.

 

[pinsog]

I found the data in this post by Tomo.



Presumably no armour as well.

Agreed, but 900 pounds difference in the XF5F made 1 mph difference in speed.
900 pound difference in F6F-3 made a 3 mph difference in top speed
Speed on a light Mustang vs heavy Mustang I believe was 3 miles an hour.

Point is, add another 1,000 pounds of weapons, ammo, armor and self sealing tanks and it should still be right there with the Hellcat. If we add turbo charged P&W 1830's, we have lowered our drag and hp is now 2,400 from SL to 25,000 feet, all available in 1941 with no magic involved.

So, why was the XF5F Skyrocket able to do same speed, at same altitude on same horsepower as the Hellcat?

 

[tomo pauk]

...
So, why was the XF5F Skyrocket about to do same speed, at same altitude on same horsepower as the Hellcat?

No guns' openings nor casings chutes on the X5F5, plus smaller wing than on the F6F. F6F has just one engine, but it features two intercoolers - those tend to increase drag. Flat, bullet-proof windscreen is more draggy than non-bullet-proof rounded/parabolic windscreen. No radio mast on the Skyrocket earns a few mph.

 

[Shortround6]

There is also the question of how much power the XF5F was really using.

The more I look at it the more I believe the chart at alternate wars is being misinterpreted.
For instance a chart on the F2A-3 with the same date gives the same power levels for the Cyclone R-1820-40. Does anybody really believe the F2A-3 really did 322mph at 14,000ft running at "Normal" power? Or did it use "Military" power which was pretty much the same as take-off power? FAA rated most of the G-200 series R-1820s at 1000hp for "take-off" at 14,200ft at 2500rpm and 44.5in for 5 minutes. This is without RAM so power at higher altitudes is dependent on the air intake and speed.

Normal power (max continuous) was 900hp at 15,200ft at 2300rpm and 40in.

And then we have what "shape" the XF5F-1 was in when those numbers were recorded.

After a number of drag reducing modifications were made?
Note exhaust outlets.

Not at all sure where turbos and more importantly, intercoolers and ducts go?
Switching to P&W R-1830s?
B-24 Nacelle without turbos

Carb intake at 12 o'clock inside cowl opening. Oil coolers under nacelle.
B-24 Nacelle with turbo

Carb intake and oil cooler are now at the 9 O'clock position and the opening at 3 O'clock is the intercooler scoop, Intercooler can be seen under the mechanics arms at rear of opening. You want 1200hp at 25,000ft you have to pay for it.

 

[wuzak]

If we add turbo charged P&W 1830's, we have lowered our drag and hp is now 2,400 from SL to 25,000 feet, all available in 1941 with no magic involved.

They did for the XP-50, and one of the turbos blew up, which led to the airframe's destruction (pilot bailed out, aircraft crashed).

The XF5F first flew in April 1940.
The XP-50 first flew February 1941.

Having either of them available in 1941 was going to be a stretch,

 

[pinsog]

WUZAK, as I said earlier, they would have to ditch the F4F-3 and only work on the Skyrocket. Unlike the Hellcat and Corsair, the technology was there in 1939, as proved by the P43. Not completely perfected, but there.

Shortround, I would definitely do the version you are showing with the longer nose and not the 1st version, but using P&W 1830's instead. Even if you ditch the turbos, you are still getting Hellcat performance. It is 35 mph faster than a Wildcat or Zero at sea level and 20 mph faster than a Spitfire MkII at sea level. It's 20 mph faster than a Zero at any altitude.

Will the turbo and intercooler fit in the back of the lengthened nacelles? Where was the intercooler on a P43? The fit a turbocharged 1830 in a P43 in 1939 in the same sized package as an F4F-3 with a 20-25 mph speed advantage over a Wildcat at any altitude.

 

[tomo pauk]

Some other US candidates:
- P-66
- F4F with turbo