These popped up for sale locally the other day and have been bouncing around in my head for a couple days now. Could they work on a car? Would they work on a car? I'm sure it would require some adaptation to fit on, oh, say, a dual carb manifold but I don't know the first thing about these kinds of carbs. They're very pretty though. Ad is as follows: Two gravity carburetors for a Pratt & Whitney 985. Both have been overhauled and I never used them because my airplane used a pressure carburetor. One Stromberg No. 5655569, R9B with parts list # of 391598-1 and One Stromberg #5798724, R9B, with parts list # of A30258-2. I do not have the yellow tags, but they were overhauled by Tulsa Engines. By earthshaker5769 at 2010-12-14
Gravity here means somewhat normal carb (though your car won't run right upside down with these...) but for 985 cubes?? One or two to feed that? the PW was probably very low RPM, but that's still huge, and as apparently single barrels they are not well equipped to run at low rpm with an engine that isn't huge. How big are those throats?? I suspect that for most car type engines below the blown max size Rodeck level, you would never get the venturis supplying. Carb fuel metering is based on airflow through a venturi that must be reasonably sized for the expected flow.
Aircraft carbs don't reall have the idle and metering circuits that auto carbs do. Also a P+W 985 means 985 cubic inches. Thats a big engine. Aircraft engines also don't see over 3000 rpm. If you could sneak an electronic fuel injection setup in there a lot of people wouls scratch their heads wondering what you have there. Also there are a lot of shops looking to buy aircraft parts cores and if these have a 8130 tag stating that they are in good order they might be worth some ca$h to you.
a 985 burns about 30 gallons per hour at 2500ish rpm. The 985 was the junior wasp and is famous for being attached to the Beech 18 (i have a few hours in one, great airplane for sure). It's a radial engine and around 400 hp. the only problem i see with an airplane carb is that the mixture is manual and would require some constant adjustment and i dont think it will work at high rpm/demand due to starvation. If they dont have yellow tags, it'll take some money to make them "airworthy" again, for resale. . probably an overhaul and 8130 tag. They'd look cool though. .heres a couple in action (i was fortunate to witness this showing): http://www.youtube.com/watch?v=EnhYC6OH6zw&feature=geosearch
There are no gas pedals in aircraft - there are no accelerator pumps and the throttles are either vernier control (friction knob that you push/pull as you twist a little bit) or throttle levers. Aside from the inherent problems of trying to operate a hand throttle with no return spring, those carbs really move some CFM - 985 is a whole bunch of engine... I have also logged a few dozen hours in a B-18 and they are indeed just a fine ride through the sky. My MES hours were derived from a beautiful Grumman Goose with uprated radials......also a sweet ride. dj
i may be wrong , but i believe that is an updraft carb.....if it is that may make it a bit hard to adapt
Well, ya can't ride upside down but I'd bet you could loop with success. It would be cool to adjust the mixture. And not having huge al***ude changes, once dialed in, you'd be fine. I don't know much about air engines, but I'd say after takeoff and inital climb, the engine may be at rpm, but not at full throttle. If one carb is good for a 400 HP engine, than one would be good on a car engine, too. And I've seen air engines idling. I don't know how slow, but not moving a lot of air. So I think the carb could handle low speed and idling, too. Very cool and worth a try.
The carbs are updraft.......I believe the "gravity" term refers to not being 'pressurized'. Pressure carbs meaning that a blower feeds through them and they are pressurized internally. I do not know for sure if ALL P&W R-985 are supercharged or not, but certainly many are. They have a centifugal blower housing at the rear of the engine case driven by the crankshaft. Another of the really great old radial engines. More to the point of your question, as others have said, the operating conditions of the aircraft engine, even for those sized nearer to auto engines, would make the carbs not very 'street friendly'. Might work better for a drag race application, but probably still not as good as an automotive carb. Ray
Dialing them in might prove to be a problem. Parts (and parts suppliers) for aircraft carburetors MUST be licensed by the FAA. Parts are NOT cheap! Jon.
a little googling and i found a picture of an engine with carb in place , just where i remember it should be
did you notice they are kinda big. radial engines normally are on the huge size. they use pistons about the size of a big coffee can. how big is the engine you would use them on. also they disigned for high al***ude and constant rpm . i think a holley or eldebrock might work a tad better
HAHAHA!! These are great answers - I love this place. You all make great points and suggestions i it was just one of those wild and wooly things that popped into my head when I saw them for $100 a piece and Steomberg. 985 cubic inches is a tad bit bigger. Obviously this is a pipe dream with a clog in it but I appreciate you guys playing along. Its really hard to tell from this one photo what the scale of these is, but I imagine they are a LOT bigger than I first thought they were.
I am experimenting with an updraft airplane carburetor feeding a supercharger because there are hood clearance advantages for updraft carbs.
Their was a thread about a Ranger Air craft engine that was used in a sprint car during the 50s. It was placed upside down and maybe backwards. I think it used the aircraft carbs.
Hello, There was some information on an old 60's sedan from Reath Automotive running similar carbs at the drags. It is on page 1761 of the Drag Cars in Motion thread. Jnaki "... those are up draft carbs off a WW II tank. Joe Reath was hung up on them for a while..." from Dean Lowe "I have heard that. I wonder what tank they came from. I have had a couple of Ford Sherman tank motors. They had two large two barrel down drafts. The updrafts remind me more of ranger aircraft engine parts. The Ranger was an inverted 6 cylinder 440 cid engine. The Ford was a 1100 inch water cooled V8." from Rich Fox.
Regardless of how applicable they may be, keep in mind that virtually anything with "aviation" attached to it is a great deal more expensive than you'd expect. Now the vintage aircraft world may be less regulated, but a buddy of mine is always complaining about the cost of his the engine parts for his experimental aircraft versus the very same parts made by the very same mfg for automotive applications. Gary
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