The Basket
Senior Master Sergeant
- 3,712
- Jun 27, 2007
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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
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.
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.
For part of that year it would've been the Brewster Buffalo....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.
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.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
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.
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"
The XF5F is tested as capable for 357-358 mph at 17300 ft, no guns, no ammo.
...
So, why was the XF5F Skyrocket about to do same speed, at same altitude on same horsepower as 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.