Brewster B-239 Buffalo Manuals

[Shortround6]

According to AHT the F2A-1s got the R-1820-34.
The 239s got Wright R-1820-G5 Cyclone which may just have had a different nameplate.

Most sources say the early engines had no reduction gear for the Propeller and AHT says that they used a 9 ft diameter HS Prop.
1939-40 is a confusing time for American engines because may engines did not have a "Military" rating.
The very similar R-1820 engine used in the Curtiss CW-21 fighter is described as being anywhere from 1000hp to 850hp.
You also had essentially the same engines being rated on 87 octane and rated on 92 octane fuel.
That may be the difference between 950hp for take-off and 1000hp for take-off?
In some cases they tried using the take-off power as "military" but many times the take-off power was one minute time limit.
Sometimes the commercial engines were "rated" at max continuous cruise instead of take-off power which dropped the early ones down to 850hp but it was still the same engine.

The engines used in the British(Belgian) and Dutch aircraft was the R-1820G-100 series engine which had a number of differences.
Like a steel crankcase instead of aluminum and like a set of reduction gears for the propeller. Just to make things confusing you will even see Curtiss Wright R-1820 engines described has having 16:11 reduction gears or 0.6875 reduction gears in the same specification chart and the gear ratio is identical.
It is the G100 series (actually the G105 in the case of the Buffaloes) that offered 1100hp for take-off, in part due to running the engines at 2350rpm instead of 2200rpm.
By using the reduction gears they could use props of 10 ft 1in (HS props) or 10ft 3 in (Curtiss propellers)

The US F2A-2 and F2A-3 aircraft got R-1820 G-200 engine which had a number of changes, like a brand new steel crankcase that would not interchange with old steel crankcase.
The US engines were rated at 1200hp for take-off and it was not just because of 100 octane fuel

You could find Wright 1820s on all kinds of things, The DC-3s, Lockheed 14s, Dornier flying boats, Douglas B-18s, Douglas SBDs Boeing 307s and the list went on.

 

[Simon Thomas]

The FAA type certificate TC154 lists a take off power of 1000 hp at 2200 rpm at 41.0" mp for the Wright R-1820-G5.
No type certificate for the DC-3 has the R-1820-G5 as an engine, but I have no doubt that at some stage a DC-3 flew with it installed sometime!

 

[Shortround6]

Wright R-1820 Cyclones can drive you nuts

Just for the "G" series engines there were 11 different models from G1 to G12 (they skipped G11?) and only two of them got TC numbers.
That is for the civilian models of which 1547 were built.

There were 14 Military models built of which 5 are listed as G5s, Why they each had a different military dash number I don't know. Change of an accessory?
there were 2545 Military G models built and apparently 731 (?) of them are identified as G5s.
The Last 216 were supposed to have gone to Grumman J2F-5s

R-1820-50

 

[Simon Thomas]

I totally agree. I am trying to figure out which 1820 model would have been in use in the DC-2 early 1935, so I can compare the performance graphs against the Bristol Pegasus VI (which was the III.M2) in the DC-2B. Seems it would have been one of either GR-1820-F1, SGR-1820-F2 or SGR-1820-F3. There was also F2A and F3A, which was the F2 or F3 with the F50 style cylinder.
I am slowly putting together a sheet with the different F series models and I am starting to see a pattern in model numbers and design parameters.
If I ever finish the F series, I may tread very gently into the G series - if I don't go mad in the process...
I will stay away from the military models - that is just asking for trouble.

 

[FLYBOYJ]

The FAA type certificate TC154 lists a take off power of 1000 hp at 2200 rpm at 41.0" mp for the Wright R-1820-G5.
No type certificate for the DC-3 has the R-1820-G5 as an engine, but I have no doubt that at some stage a DC-3 flew with it installed sometime!

Good catch! I went back and looked at the TCDS for both aircraft and engine and couldn't find anything about he -G5 being used on the DC-3 however, several internet sources say that the R-1820-G5 was used on the first DC-3s, of course I can't find any hard reference for that.

 

[Shortround6]

I doubt that the G5 was used in the DC-3.
The Wright data sheets I am using may have some mis-prints/typos.
Most G5 engines are listed as not having reduction gears and why anybody would put an R-1820 with a small diameter fast turning prop on a DC-3 is beyond me.
Apparently the number after the Letter is supposed to designate the gear ratio of the supercharger.
The G5 used a two speed supercharger while the some of the other versions use single speed superchargers.

The fuel required for the G series includes 80 (one model) 87, 92 and a few with 100. there is one lonely entry listed at 100/130 but that is for the engine used in the Brewster/Naval Aircraft Factory SNA-1/SBN-1.

Since the last was delivered in March of 1942 I suppose some paperwork somewhere may have listed 100/130 fuel but it didn't change the power rating


BTW I have not found any early DC-3s that were listed as having (or leaving the factory) with G5 engines but I don't have a complete list. The G5 was listed as a option.
Some of the earliest DST (Douglas Sleeper Transport) used G2 engines. There were 21 of the DSTs built but they were built with G2s, G102s and G-202s.

 

[FLYBOYJ]

It seems the prototype of the B-18 (DB-1) had the R-1820-G5, at least according to Joe B:

Douglas B-18 Bolo

Now I did find this site, I would guess SR might have already seen this:

The R-1820 “Cyclone” Versions

I decided to write a post about the first decade of the R-1820 “Cyclone” development (up to the R-1820-60 version, i.e. 1940). This engine was used in many designs from 1930s, and you can find the …

airplanes3d.wordpress.com

So going back the the Buffalo (I deleted referenced made to photos from the original link) -

The next "Cyclone" model was the R-1820G. It had larger cylinder heads than the "F" version (as explained in this article, to get higher power from a cylinder, you need the larger area of its cooling fins). I have found some detailed pictures of an early, direct-drive "G" versions in the F3F-2s restored at Chino Planes of Fame. Comparing to the original photos, it seems that this is not the R-1820G5 (R-1820-22), but another "Cyclone" version. However, it seems to be nearly identical with the original engine. the intake duct in the heads is set at about 45⁰ to the centerline, as in the blueprints of my R-1820-60 version. (In the "E" and "F" models it was parallel to the centerline, as the exhaust duct). The intake valve is finally covered by short fins. The spark plugs are thinner, and placed in a less asymmetric way than in the "F" model (in fact, this head looks similar to the version that I recreated in the previous post). The top rocker covers received the new shape and four bolts around their rims. On the left photo you can see the attachment points on the rocker covers, introduced in the "F" version (they are more visible here than on the previous picture). The higher pressure produced in the combustion chambers of this engine increased the number of attaching bolts to 16 per cylinder (there were 12 in the "E" and "F" versions). The original R-1820-22 (GR-1820G5) engine, used in the F3F-2, was rated at 950hp for takeoff. (The same engine was used in the F2A-1 Buffalo, and the export version of this fighter, Brewster 239, delivered to Finland).

 

[FLYBOYJ]

I doubt that the G5 was used in the DC-3.

I'm beginning to believe the same

The Wright data sheets I am using may have some mis-prints/typos.

Yep!

Most G5 engines are listed as not having reduction gears and why anybody would put an R-1820 with a small diameter fast turning prop on a DC-3 is beyond me.

100%

Apparently the number after the Letter is supposed to designate the gear ratio of the supercharger.
The G5 used a two speed supercharger while the some of the other versions use single speed superchargers.

The fuel required for the G series includes 80 (one model) 87, 92 and a few with 100. there is one lonely entry listed at 100/130 but that is for the engine used in the Brewster/Naval Aircraft Factory SNA-1/SBN-1.
View attachment 666474
Since the last was delivered in March of 1942 I suppose some paperwork somewhere may have listed 100/130 fuel but it didn't change the power rating


BTW I have not found any early DC-3s that were listed as having (or leaving the factory) with G5 engines but I don't have a complete list. The G5 was listed as a option.
Some of the earliest DST (Douglas Sleeper Transport) used G2 engines. There were 21 of the DSTs built but they were built with G2s, G102s and G-202s.

Saw the same - see my post above

 

[Shortround6]

One of my go-to articles is the "Torque Meter" Volume 2, number 3. Journal of the Aircraft Engine Historical Society.
The article is 12 pages by Kimble D. McCutcheon and runs though the Weight P-1 to the TC9J2 which was an experimental Turbo compound engine from 1951.

It has several differences to the article you linked to above. It concentrates on the difference between the different series engines and skips over the variations within the series.
Otherwise we may be looking at a small (or not so small) book

There are 19 pages just to list the different model Curtiss Wright engines from 1930 to the end of production.

 

[ThomasP]

I have seen reference to the R-1820-G5 engine used on some of the early DC-3 that were taken up from the civil airlines for military service. This G5 variant was the Model 286T which had a reduction gearbox fitted. Reduction ratio was 16:11. The military designation was R-1820-71 (I think).

 

[Elvis]

I believe the Finns got an F2A-1 variant (Brewster model B-239E, the F2A-1 was a model B-239) It didn't have armor, self sealing tanks, an arrest hook, carried 2 extra guns and had a more powerful engine.

The engine was an export version of the R-1820 used in the F2A1. They also changed the radio and the gun sight.

 

[Elvis]

One other tidbit...the F2A-1 and Model 239 had the least powerful engine of any variants, just 950hp IIRC.

Buffnut,

Do you know if the engine used in trials for the XF2A was different from the one used in the F2A-1?

 

[Elvis]

I have seen reference to the R-1820-G5 engine used on some of the early DC-3 that were taken up from the civil airlines for military service. This G5 variant was the Model 286T which had a reduction gearbox fitted. Reduction ratio was 16:11. The military designation was R-1820-71 (I think).

Could be referencing the B-18 Bolo bomber version of the DC3.
That plane used R1820-53 engines, rated at 930 hp.

Douglas B-18 Bolo - Wikipedia

en.wikipedia.org

 

[FLYBOYJ]

The engine was an export version of the R-1820 used in the F2A1. They also changed the radio and the gun sight.

Yes but which dash number or letter? From sources it's being shown the engines on the 239's delivered to the Finns put out at least 10 HP more

 

[FLYBOYJ]

I have seen reference to the R-1820-G5 engine used on some of the early DC-3 that were taken up from the civil airlines for military service. This G5 variant was the Model 286T which had a reduction gearbox fitted. Reduction ratio was 16:11. The military designation was R-1820-71 (I think).

I've seen it too but the TCDS doesn't show it as an original installation, that's not to say some were installed with a Field Approval

 

[Elvis]

Yes but which dash number or letter? From sources it's being shown the engines on the 239's delivered to the Finns put out at least 10 HP more

From what I remember, the B239 got the G5 engine. The F2A1 got the -34.
Yes, the export engine made 10 more HP (950 vs 940).
If anyone has the November 1996 issue of Aviation History, it will literally answer all the questions you guys are asking.

Fun Fact:
as the B239's were wearing out during the Continuation War, some planes were repowered with Shvetsov M63's harvested from downed I-16's.
However, the Finn's found that the engines were built so crudely, they were literally custom fit pieces, so a part from one engine could not be used on another.
If you had a cylinder or two shot out, you had to replace the whole engine.
Towards the end of hostilities, most of the Finnish fighter groups had replaced their worn out B239's with ME109's. Once the skirmish had ended, Finland bowed out of the "big war" and went back to being a neutral nation.

 

[Shortround6]

I think (?) The "5" in the designated refers to the supercharger gear ratos.
Which means in the case of the "5" a 2 speed supercharger.
Propeller reduction gear could be present or not,

 

[buffnut453]

Buffnut,

Do you know if the engine used in trials for the XF2A was different from the one used in the F2A-1?

I need to check sources but I think it was a Wright Cyclone Model R1820-22 which generated 950hp as opposed to the -34 used in production F2A-1 airframes which only gave 940. Seems odd that a prototype would have more power than a production variant but, hey, it's Brewster so anything could happen!

 

[FLYBOYJ]

If anyone has the November 1996 issue of Aviation History, it will literally answer all the questions you guys are asking.

I remember seeing that issue but at the same time, as SR pointed out earlier in this thread, there's been many mis-prints and errors with regards to to the 1820 and model designations so information on this is all over the place!

As Buffnut said - "it's Brewster so anything could happen!"

Bottom line - the Finns did not get F2A-1s, their model 239s had many differences than the F2A-1 to include the engine (if the details can ever be accurately be sorted out). As much as I would like to see an F2A of any version restored, I think it's terribly wrong to have BW-372 identified as an "F2A-1" and displayed as an American asset at Pensacola. The aircraft belongs in Finland and I hope it stays there forever!

 

[ThomasP]

Hey Elvis,

In the Curtiss-Wright R-1820 engine model list the R-1820-34 was a single-stage/two-speed variant of the G5, without reduction gear, compression ratio of 6.45:1, with 950 BHP for TO and 850 BHP Normal at SL. It was listed as fitted to the following airframes:

Brewster F2A-1 Buffalo
Curtiss SBC-4 Helldiver


In the Curtiss-Wright R-1820 engine model list R-1820G5 Model 286T (there were 154 engines of this model produced) it is listed as single-stage/two-speed with reduction gear of 16:11 (or .6875:1), compression ratio of 6.45:1, with 1000 BHP for TO and 850 BHP Normal at SL. It was listed as fitted to the following airframes:

Brewster F2A-1 Buffalo
Brewster Model 239 Buffalo
Curtiss CW-21 Demon
Curtiss Hawk 75-0
Martin 139WH
Douglas DC-3
Vultee V-1A

I went through the entire list and can not find a DC-3 (or variant thereof) that used a R-1820 without reduction gear.


re the R-1820-71 designation

The engine model civil/military designation used on some of the C-49 is R-1820-71 (not the R-1820G71/R-1820-53 used on the B-18A/AM/B Bolo).

In the Curtiss-Wright R-1820 engine model list the R-1820-71 is also listed with the WAD internal model number C9CC1 and Model Spec No 702.
It is a single-stage/single-speed having 1200 BHP for TO with a reduction of .666:1 (or 3:2). It was listed as being fitted to the following airframes:

Douglas C-49,-49A/B/C/D
Lockheed C-60
Lockheed C-56E

So I am thinking the R-1820-71 is from a later re-engining of the C-49, C-49A/B/C/D ???