Wright Cyclone 9 for US fighters (1940-1945)

[Vincenzo]

I'm checking what Cyclone 9 1820 models, and their power, were mounted in the fighters built in the US in the 1940-45 time
After a bit of research i've found
the GR-1820G5 was on the Brewster 239 and the CW-21; the engine had a TO power of 1000 HP at 2200 rpm with 87 octane fuel, i've not found the power at FTH
the GR-1820G105A was on the Brewster 339B,C&E; the engine had a TO power of 1100 HP at 2350 rpm with 91 octane fuel, i've not found the power at FTH
the GR-1820G205A was on the Brewster 339D, Martlet I and the Hawk 75A-4,-7,-8,-9 (also known as Mohawk IV); the engine had a TO power of 1200 HP at 2500 rpm with 100 octane fuel
under the name R-1820-87 this engine was mounted in the 339D and in F4F-4B and under the name R-1820-95 was on the P-36G (75A-8), the power of G205A model at FTH was 900 HP at 2300 rpm @ 15,200 feet.
the R-1820-40 was on the F2A-2,-3; the engine had a TO power of 1200 HP at 2500 rpm with 100 octane fuel, i've not found the power at FTH
the R-1820-40B was on the F4F-4B (also known as Martlet IV); the engine had the same power of -40
the R-1820-56 was on the FM-2; the engine had a TO power of 1300 HP at 2600 rpm with 100 octane fuel
i've not found the power at FTH; the FM-2 used also the variant -56W&56WA with water injection (the WA with 50 HP and 100 rpm more to TO).
it's also reported that the FM-2 use also the R-1820-72A and -74W engines, the -72A with the same power of -56WA and the -74W with 1425 HP at 2700 rpm to TO with 100/130 octane fuel.

You can check this data and add some others?

 

[Shortround6]

You may not find "military" power at altitude ratings for the early (pre war or early war) engines. They may not have been rated that way.

Here is an FAA listing of Wright Military R-1820s;

http://rgl.faa.gov/Regulatory_and_G...34d78525676a006354ef/$FILE/ATTNWJTA/5E-10.pdf

This for using the engines in civilian use.
Sometimes you can use the "Take-off (5 minute) HP-RPM- in Hg-at critical altitude (ft)" entry line as an an approximation of military power.
like for the -40,-6- amd -40C engines it is listed as 1000hp/2500rpm/44.5in/14,200ft.

Since that is the same RPM and within 1in (lower)manifold pressure than the engine used for take-off at sea level I figure that is as good as it is going to get.

Please note that for civilian use the water injection equipment was removed from the engines that had it.

Max continuous or cruise power ratings should be pretty much the same.

 

[Vincenzo]

Was my intention give also the production number for the fighters but i've not remembered yesterday, also now check/adds are welcomed
so
Martlet I (G-205A) 91 delivered from may '40 to sometime in '40
Martlet IV (-40B and probably -87(205A) as replacement engine) 220 delivered from ? to november '42
FM-2 (-56 and others see post 1) 4,777 delivered from september '43 to may '45
Mohawk IV&Hawk-751 (G-205A) ~300 delivered from 6/40 to sometime in '41 (this include aircraft ordered as A-4, A-7, A-9)
Hawk 75A-8/P-36G (G-205A) 36 (for pratical purpose as Mohawk IV) delivered in february '41
Demon 21 (G-5) 3 + 27 sets
Demon 21B (G-5) 24 maybe, delivered from 6/41 to ?
239 (G-5) 44 delivered in january and february '40
339B (G-105A) 40 delivered from april to july '40
339C (G-105A) 24 delivered in march and april '41
339D (G-205A) 48 delivered from april to june '41 plus one delivered in april '42
339E (G-105A) 170 delivered from january to april '41
339-23 (G-5) 20 delivered from january to april '42
F2A-2 (-40) 43 delivered from september to november '40 and the last in january '41
F2A-3 (-40) 108 delivered from july '41 to january '42

 

[Shortround6]

You may be well aware of it but you are comparing/listing 4 different engines.

The R-1820G5 (or any R-1820G) was the oldest of the 3. 4092 "G"S being built between April 1935 and Sept 1945.
This engine used a forged aluminum crankcase and was limited to 2200rpm max for take-off (or for military purposes?)
Early ones were rated on 87 octane but later ones used 91 octane or 91/96. 1000hp max in low gear (if equipped with 2 speed supercharger) or if fitted with a low supercharger ratio ( 6 different gear ratios were available for order, not all may have been used?)

The R-1820 G100 series shifted to a forged steel crankcase (30lbs heavier but 50% stronger) and a number of other changes. 5219 were built between Jan 1937 and June 1943.
Early ones used 87 or 91 octane fuel, later ones used 100 octane.
Rpm was limited to 2350rpm for take-off (or military?) and take-off power was 1100hp in low gear or lower supercharger ratios.

The R-1820 G200 series changed the crankcase again. Still a steel forging but back to the weight of the aluminium one while being even stronger than the G100 steel one. This (and many other changes including larger roller bearings for the crankshaft) allowed for 2500rpm for take-off and military power.
These are the 1200hp for take-off engines. 22,200 were built by Wright (and tens of thousands more by other companies) between March of 1939 and May of 1945.

The 1300-1350hp engines (and higher) were the "H" series engines, the first of which show up in October 1942. Again major changes to construction allowed for higher power and better cooling. Since they kept building the "H" until 1963 it had the most changes and one has to be very careful as to what specifications are being used. The 1300-1350hp engines ran at a max of 2600rpm and the 1350engine required a different crankshaft. The later "H" engines went to 2700 and then 2800rpm and also ended up using 115/145 fuel (post war).
The FM-2s got the early "H" series engines.

Please note that unlike Allisons or Merlins there is no swapping (or darn little) newer parts into older engines (or vice versa) as so much changed between the different series engines.

The caption is mistaken as the cylinder fins on the right were introduced on the R-1820 with the H series engines in late 1942 although the cylinder on left continued to made until the end of the war. The cylinder (not head) fins on the right were sheet metal that were pressed into grooves cut in the cylinder barrel.
This style of fin was used on the 1900hp R-2600s and Some of the R-3350s.
There were also multiple styles/shapes of fins between 1931 and 1939.

I would note that R-1820 development sort of stalled between early 1939 and 1942. In part because of the need to expand production and in part because more the R&D was going into the R-2600, R-3350 and the R-2160 Tornado (which turned into a black hole, swallowing millions of dollars and thousands of man hours for no practical result)

 

[Elvis]

Vincenzo,

You may not remember me, but you and I came here about the same time.
Its been many years since we've chatted. Nice to see an old friend again.
I hope all is well with you.
I just wanted to comment on the Brewster you mentioned in your initial list.
From what I remember, "B-239" and other similar designations were the company's names for these planes.
In USN service, the Buff was the "F2A-...".
The B-239 was the F2A-1.
In USN service it was outfitted with an R-1820-22 of 950 hp.
When those planes were sent to Finland (thus clinching Brewster's sale of their "improved" B-339 to the USN), those engines were pulled and replaced with the older G-5 variant that you listed.
Same HP, but I believe at least one difference was the cylinder head on the "-22" had a better fin arrangement, thus cooling was more efficient.


Elvis

 

[Vincenzo]

Yes i remember, nice to see you. Well but 11 years ago was better, too me hope is all ok for you.
AFAIK the F2A-1 had the -34 engine that was a 950 hp TO power
http://www.enginehistory.org/Piston/Wright/C-WSpecsAfter1930.pdf

 

[Elvis]

Yes i remember, nice to see you. Well but 11 years ago was better, too me hope is all ok for you.
AFAIK the F2A-1 had the -34 engine that was a 950 hp TO power
http://www.enginehistory.org/Piston/Wright/C-WSpecsAfter1930.pdf

...oops....
Sorry about that. You're right, of course.
Nice to hear you remember me. I am fine, just dealing with getting older.. I'm sure you understand.


Elvis