High altitude Wright R-1820

[Elvis]

Does anyone know if Wright ever built an R-1820 with a two-speed / two-stage supercharger?
I was just thinking about that and did a Google search, but to no avail.
Anyone know?


Elvis

 

[Shortround6]

Never heard of one but that doesn't mean they didn't have one hiding in a test cell or test hanger somewhere.

edit, found one.

C9GC-1 R-1820-46 model spec number 622 weight 1422lbs, length 57.4 inches (about 7-10in longer than the single stage engines)

ONE built in Jan 1941 for a Brewster XFLA-4

Power ratings in chart are for sea level.

http://www.enginehistory.org/Piston/Wright/C-WSpecsAfter1930.pdf

 

[Elvis]

Thanks Shortround6. Been so long since I've been to that site, I'd forgotten what it was called.
Interesting that the engine never made it past the experimental stage for an experimental aircraft...might have made the FM-2 a higher altitude threat.


Elvis

 

[GregP]

The R-1820-67/69/97 were fitted with turbochargers.

The -97 was used in B-17E/F/G and a Northrop model I don't recognize (N-1-25A, according to that paragon of correctness, Wiki). I don't know that the -67 / -96 were used in actual aircraft. If so, I don't know which ones.

They put a turbocharger in the R-1830-35, too, I think, but I can't recall a 2-stage R-1830 either.

They definitely made 2-stage R-2800s, but my bet is that the extra weight of a 2nd stage would add too much weight to the little 1820 / 1830-size engines. I doubt if the slight HP addition would be worth the penalty in weight. Might help the service ceiling, but you have to have performance when you get there, too.

Edit: Look above about two posts or so for Shortround's answer. There seem to be several 2-stage and 2-speed R-1820 models used in several aircraft including the DC-3 and some Grumman and Brewster aircraft. Never knew that, and am now somewhat interested.

Thanks! Shortround!

 

[Shortround6]

The Majority of F4F and FM-1 Wildcats used two stage supercharged P&W R-1830s. The FM-2 switched to the Wright R-1820 but single stage.

Wright moved to two speed superchargers at least a year before P&W did, perhaps closer to two years? P&W was flying two stage engines in very late 1938 or early 39 (two showed up at the 1939 Army fighter trials) but production R-1830s with two speed superchargers don't seem to show up until late 1940 or early 1941? Very first French DB-7 have single speed superchargers, First batch of Martin Marylanders have single speed superchargers.

Some C-47s got two stage superchargers for flying the hump in India/China. Some PBYs got two stage superchargers????

 

[swampyankee]

Thanks Shortround6. Been so long since I've been to that site, I'd forgotten what it was called.
Interesting that the engine never made it past the experimental stage for an experimental aircraft...might have made the FM-2 a higher altitude threat.


Elvis

The B-17 had turbocharged R-1820s. This probably eliminated the USAAF's interest in high-altitude R-1820s. The FM-2 didn't need to be a high-altitude threat; there wasn't one in the Pacific (as the Japanese didn't have a guided missile other than the kamikazes, aircraft at 30,0000 ft were not a threat). In the Atlantic, there was very limited combat between RN, USN, and Luftwaffe aircraft. While I don't think that a reasonably well-flown Wildcat would be cold meat for an equally well-flown Bf109 or FW190, I'd not like to be the USN or RN pilot to do that experiment.

 

[Shortround6]

I don't know when production of the FM-2 started but the first examples left the production line in Sept of 1943. Prototypes had Flown in Dec of 1942. The FM-2 was intended for use on the escort carriers. The Big carriers were pretty well equipped with F6Fs with two stage superchargers (or plans to change over the F4F/FM-1 squadrons were well in hand) with F4Us going to land based squadrons also with two stage superchargers. This meant the need for two-stage supercharged Wildcats was not particularly pressing. The need for some sort of fighter to operate from short slow carriers was.

Grumman had delivered about 790 Hellcats by the time the first FM-2 shows up with Vought and partners delivering about another 1180 Corsairs at that time. Grumman would average about 500 Hellcats a month in 1944.

Please note the F8F Bearcat was a FM-2 replacement. Intended for use off escort carriers and it too did NOT have a two stage supercharger.

And again, the Eastern AIrcraft FM-1 did have a two stage supercharger. Eastern Aircraft had a contract for 1800 FM-1s of which they produced 839 for the US Navy and 311 for the British Navy. Contract changed (I assume) to cover the change to the FM-2

 

[Elvis]

I can't recall a 2-stage R-1830 either.

Later F4F's had them.
I remember a website that dealt with the Swedish J22. It was owned by an aeronautical engineer and he was able to calculate performance for that plane, if it had a 2 sp/2 stg. SC.
I remember he called it a "J22C".
Surprising to read so many examples of 2sp/2stg 1820's. You guys are definitely better at research than I! =)


Elvis

 

[Elvis]

Please note the F8F Bearcat was a FM-2 replacement. Intended for use off escort carriers and it too did NOT have a two stage supercharger.

...wasn't the F8F based on the idea of a "trimmed down" F6F?
That's the way I've always understood it.


Elvis

 

[Shortround6]

Could be but since the F8F used about 74% of the wing area, a different wing fold, different landing gear, a single stage supercharger, was also about 4 1/2 ft shorter it pretty much seems they simply threw the F6F out and started over.

They were trying to design the smallest fighter they could around an R-2800 engine so using a clean sheet of paper would make sense rather than trying to "cut down" and F6F.
Please note the F8F was started in the Spring of 1943 and development work on the P & W "C" series R-2800 engine was nearing completion, first production engines were only a few months away. The "C"s had better finning for more cooling with the same airflow. They ran a bit faster, offered an extra 100hp without using "emergency" power and some other benefits over the "B" engine in the F6F.

 

[Elvis]

They were trying to design the smallest fighter they could around an R-2800 engine so using a clean sheet of paper would make sense rather than trying to "cut down" and F6F.

Maybe that's what I was thinking of.
You're right, it does make more sense to take that approach.
Apologies for the misquote.
Difference you mentioned between B and C model R-2800's seem to mimic the development of P&W radials in general....seems they were always looking for a better way to cool the engine.


Elvis

 

[Elvis]

...from Wiki's page on the R-2800...


"C" Series

A "C Series" R-2800, with the two section nose casing incorporating torque-monitoring equipment and a Spark Advance unit, with the "outboard" sparkplug wiring conduit location for each of the twin enclosed distributors.

• 
  
  
  • R-2800-18W

2,100 hp (1,566 kW) at 2,800 rpm at 1,000 ft (305 m); 1,800 hp (1,342 kW) at 2,800 rpm at 25,500 ft (7,772 m).[20] First series production variant of the "C" Series, which was a complete redesign of the R-2800. Some of the main changes were forged, rather than cast cylinders, allowing an increased compression ratio (from 6.65:1 to 6.75:1), a redesigned crankshaft, a single piece, rather than split crankcase center section, and a two section nose casing, incorporating hydraulically operated torque-monitoring equipment and an automatic, vacuum operated spark-advance unit.[21] The supercharger used fluid coupling for the second stage.[22] Updraft Bendix-Stromberg PT-13G2-10 carburetor. Used in Vought F4U-4 and -4 variants.[nb 5] Production = 3,257 (P&W).[24]

• R-2800-22W - 2,400 hp (1,789 kW)
• R-2800-25 - 2,000 hp (1,490 kW) — for Northrop P-61 Black Widow
• R-2800-27 - 2,000 hp (1,491 kW)
• R-2800-30W ("E" Series) - 2,250 hp (1,677 kW)
• R-2800-31 - 2,000 hp (1,491 kW)
• R-2800-32W ("E" Series) - 2,450 hp (1,827 kW), 2,850 hp (2,125 kW) with water-methanol injection
• R-2800-34 - 2,100 hp (1,567 kW)
• R-2800-34W - 2,100 hp[25] (1,567 kW), 2,400 hp (1,789 kW) with water-methanol injection
• R-2800-39 - 2,000 hp (1,491 kW)
• R-2800-41 - 2,000 hp (1,491 kW)
• R-2800-43 - 2,000 hp (1,491 kW)
• R-2800-44 - 2,300 hp (1,700 kW)
• R-2800-44W - 2,400 hp (1,789 kW)
• R-2800-48 - 2,500 hp (1,890 kW)
• R-2800-48W - 2,400 hp (1,789 kW)
• R-2800-51 - 2,000 hp (1,491 kW)
• R-2800-54 - 2,100 hp (1,567 kW)
• R-2800-57 - 2,800 hp (2,090 kW)
• R-2800-57C - 2,800 hp (2,090 kW)
• R-2800-59W - 2,500 hp (1,890 kW)
• R-2800-65 - 2,000 hp (1,491 kW)
• R-2800-65W - 2,250 hp (1,677 kW)
• R-2800-71 - 2,000 hp (1,491 kW)
• R-2800-73 - 2,800 hp (2,090 kW) — with General Electric CH-5-A3 turbocharger[26] for P-61C Black Widow
• R-2800-75 - 2,200 hp (1,640 kW)
• R-2800-77 - 2,800 hp (2,090 kW)
• R-2800-79 - 2,000 hp (,1491 kW)
• R-2800-83 - 2,100 hp (1,567 kW)
• R-2800-83AM - 2,100 hp (1,567 kW)
• R-2800-99W - 2,300 hp (1,700 kW)
• R-2800-103W - 2,500 hp (1,890 kW)
• R-2800-2SB-G - 1,850 hp (1,379 kW)
• R-2800-CB16 - 2,400 hp (1,789 kW), 2,500 hp (1,890 kW)
• R-2800-CB17 - 2,500 hp (1,890 kW)
• R-2800-S1A4-G - 1,850 hp (1,379 kW)
• R-2800-S1C3-G - 2,100 hp (1,567 kW)

According to the Wiki page on the F8F-1, the engine used was the "...-34W", with the "W" denoting (as usual) water-methanol injection.


Elvis

 

[Shortround6]

A few things wrong with Wiki, The cylinder heads were forged with much more fin area. The cylinder barrels, instead of being one piece with machined in fins, were two piece. The steel liner and an aluminum "muff" with the cooling fins.
The 18W didn't use a hydraulic coupling for the second stage, it used the same gear set up as the older engines. A number of "C" series engines did use hydraulic couplings, including both single stage engines and the aux stage of the -32 engine which used dual superchargers feeding a large single stage main supercharger.

 

[Elvis]

Yeah, Wiki can be a bit "generalized" in their statements from time to time.
I wouldn't say the article is wrong, though, just not as specific as it could be (could be the info wasn't known to them at the time it was written. You should go in there and make it more specific).
Were the liners removable in those cylinders?

 

[Shortround6]

Were the liners removable in those cylinders?

Not without a lot of work.
They were set up to to be an interference fit, OD of the steel liner was smaller than the ID of aluminium muff. Steel part was cooled and aluminium was heated and a hydraulic press pushed them together.

BTW that was pretty much the way the head was held on. Heated cylinder head was screwed onto cooled cylinder liner. Once they were the same temperature chances of them coming apart are about nil.

 

[GregP]

Removal of ANY liner requires work. None are all that difficult, IF you have the right tools.

It isn't all that hard to get Allison liners out, but most people don't even try. And it doesn't take all THAT much effort. Joe Yancey can pull all six liners from one cylinder bank in about 2 hours. About the same to out new ones back in. While it may take tools and time, it isn't all that hard. He also does Bristol Centaurus cylinders, too. As far as I know, he's the only guy around who has figured out how to get a Centaurus cylinder honed round and the ring step ridges removed, both at the same time. Again, not all that hard, IF you know how.

When Joe started, he didn't have cylinder liner tools. He built them and they work great. Still do.

 

[Elvis]

shortround6,

Ok, so those are the "permanent" liners. Gotcha.
When I was a kid, I had a Chevy Vega and we had to have that engine sleeved at one point.
Same thing as what you mentioned.
Thanks for clearing that up. Much appreciated.
I would imagine a lot of aircraft engines have lined cylinders these days, especially with the LSA powerplants.
Would allow for more aluminum used in the engine's construction, making it very light weight.


Elvis

 

[Shortround6]

We may be talking apples and oranges. On a V-12 engine the cylinder liners may be intended to to be replaced during overhaul if not up to specification. Otherwise you junk the whole cylinder bank.
On a radial with a steel cylinder and barrel and machined fins if the cylinder is out of specification you change the cylinder barrel (or barrel and head?).
On a radial with with a steel liner and aluminum cooling fins around it do you replace the liner or do you replace the whole individual cylinder?

I don't have an overhaul manual for a "C" series R-2800 and that is the only way to know for sure what the factory intended.

What a skilled and talented machine shop operator can do facing a shortage of parts I don't know.

 

[Elvis]

From what you've told me, I would think you'd replace the entire cylinder.
Those liners aren't meant to be replaced and with the individual cylinders easily able to be detatched from the block, that would be my guess.
In that sense, it would be like working on a motorcycle engine or an air-cooled VW engine.


Elvis

 

[GregP]

There is no need to change the head. Just a liner in the cylinder (assumes a steel liner). Of course, if you are into the cylinder, you would normally grind the valve seats anyway. Normally, they change out a cylinder barrel (easier if spares are on hand) but, if you're out of them, you can change liners if you know how. It's what the "factory" did when they refurbished a cylinder that was out of spec and if the liner couldn't be honed satisfactorily. All steel liners can be honed, but there reaches a thickness of liner where the steel is too thin to stand the heat and still retain its round shape, so they get changed out.

In modern times, if the liner has been chromed, you can't bore it because the Chrome is harder than the stone used to hone it with. If I owned a small plane, I'd NOT have chome bores!

For example, if you go by the Allison book, there are only three liners: nominal, 0.010" overbore, and 0.020" overbore. Anything that is at .020 over cannot be honed bigger. The normal procedure is to run either a nominal or an 0.010" liners in the cylinder and proceed. Radials also have a max overbore spec. They're like big, airborne Harley Davidsons and are not difficult to work on once you get trained. They take time, yes, but and not "hard."