Supercharger stageing, compounding,

[floydjer]

How about using an exhaust driven turbo to deliver air through an inter-cooler and on to a crank driven compressor? Semi "free" cold inlet air already under slight boost.  J.B.

[jl222]

How about using an exhaust driven turbo to deliver air through an inter-cooler and on to a crank driven compressor? Semi "free" cold inlet air alredy under slight boost.  J.B.

  J.B.

 I'm pretty sure one version of the R3350 that used twin turbos blew through intercoolers before intering the centrifugal on back of engine. The Pratt & Whitney R2800 two stage engine [centrifugals] did.
 
 For those that don't know R stands for radial engine and 3350 or 2800 is cubic inchs.

   JL222

[Dynoroom]

Mack truck and a few other companies use what is called a "tip turbine fan" which uses bleed off boost pressure to turn a axial flow fan to blow air across the chargeair cooler. Needed because of low air flow and high output in some applications like hill climbing or

There are also similar devices used to pressurize the cabins in aircraft at high altitude.

[jl222]

How about using an exhaust driven turbo to deliver air through an inter-cooler and on to a crank driven compressor? Semi "free" cold inlet air alredy under slight boost.  J.B.

 
  If the crank driven blower put out 14.7 lbs boost [pressure ratio of 2] and the turbos 14.7 [pr 2] its 2 x 2 = pr 4.
 4 x14.7=58.8 lbs - 14.7 =44.1 lbs boost. Air flow has to be figured to do this a lot more air from turbos into 1st blower.
 This is why aero engines were staged instead of adding blowers.

     JL222

[floydjer]

I`m a little slow........Using the turbo(s) for nothing more than air delivery to the blower/intercooler I`d need 2x the air flow?   Jerry

[jl222]

I`m a little slow........Using the turbo(s) for nothing more than air delivery to the blower/intercooler I`d need 2x the air flow?   Jerry

   No I was just describing the results at that boost level. But any air from 2nd tubo or blower has to be more than first blower other wise it would be choked down.
  I guess what your talking about is using the air just to help turn the blower which would help, but if you supply extra air you get the benifits of more power to turn 1st blower and more power to engine.

      JL222

       

 
   

[RichFox]

When I was working in the piston engine overhaul shop at UAL besides the Turbo-Compound 3350s we mostly did P&W 2800s. The ones from DC6s weren't anything special but the ones for Conviars were exhaust augmented. What that meant was they had really cool headers that cane over the wing in the engine nacelle and provided some thrust. 2800 inches of blown hemi on take off power puts out some exhaust pressure. You should have been there when they ran them on the dyno. I wounder if exhaust could be optimized to provide thrust on a Bonneville car?

[jl222]

When I was working in the piston engine overhaul shop at UAL besides the Turbo-Compound 3350s we mostly did P&W 2800s. The ones from DC6s weren't anything special but the ones for Conviars were exhaust augmented. What that meant was they had really cool headers that cane over the wing in the engine nacelle and provided some thrust. 2800 inches of blown hemi on take off power puts out some exhaust pressure. You should have been there when they ran them on the dyno. I wounder if exhaust could be optimized to provide thrust on a Bonneville car?

   Yea Rich we believe we get downforce and thrust on the 222 car from our zoomies. I read that one reason Rolls Royce didn't go to turbos because of the thrust they would lose. Up to 200 thrust hp!
   I wish I could have been there on those dyno runs I bet the whole place shook.
  Those old engines were master-pieces and they are being forgotton but we haven't done some of the supercharging techniques that they did.
 

        JL222
   

[Seldom Seen Slim]

I suppose there are other places, but - if you've got some time when you're in the Salt Lake City area, go up the road a few miles to the Hill AFB air museum.  They've got a cutaway of a piston aircraft engine (I forget what model), and it's indeed, a masterpiece.  Push the button on the display and a little motor drives it so you can see the internals as they move.  Quite a complex device.

The museum is worth the trip.  You get to walk around and all but touch an SR71, see some video and slides of WWII planes and flyers, and so on -- a good way to spend the afternoon.

[jl222]

Slim

   I was there and spun that engine a Pratt and Whitney R4360 36 cylinders 4 rows of 9 and a crankshaft out of a V12 Allison next to it standing on end seemed almost 6 ft tall. The impellers in our 1st superchargers looked the same shape as the R4360 except a whole lot smaller.
 The air museum in San Diego has a cutaway of a sleeve valve radial that you can spin also

      JL222

[Rex Schimmer]

JL222,

R4360, 4 rows of 7 cylinder. A close friend of mine, Harry Haggard, has one off of the Spruce Goose. He got a couple extra cylinders and heads in the container when he got the engine and we were always going to make a 156 cu. inch single cylinder motor cycle engine with one of the barrels and heads , figured when it would idle the piston would be stopped and the motorcycle would jump up and down!

Rex

[maguromic]

"figured when it would idle the piston would be stopped and the motorcycle would jump up and down!"

Rex, That's funny.  Reminds me of the vertical pedal  bicycle that Trevor Harris designed for Huffy.

[jl222]

JL222,

R4360, 4 rows of 7 cylinder. A close friend of mine, Harry Haggard, has one off of the Spruce Goose. He got a couple extra cylinders and heads in the container when he got the engine and we were always going to make a 156 cu. inch single cylinder motor cycle engine with one of the barrels and heads , figured when it would idle the piston would be stopped and the motorcycle would jump up and down!

Rex

  Yea I thought I might be wrong on that because a double R2800 would be a R5600
  That engine must be worth a fortune, whats he going to do with it [unlimited air racing in a corsair]?

       JL222

    I've got a blower to go with that cylinder

[interested bystander]

The amazing thing about those beautifuly executed and powerful engines is that they were machined by men (and women) who were turning handles!

[Rex Schimmer]

JL222,
Right now it is residing in his hanger at the Torrance airport. Back in the early 80s when Hughes AC was sellling the Goose a friend of Harry's that worked at Hughes called him and said the spare engines for the Goose were being "given" away. To qualify you had to be some kind of group that would use the engine for education etc. so Harry became a "boy scout troop"! He and I were sharing a shop on Signal Hill at the time and one day this big flat bed truck pulls up with this giant army green can on it. The motor was in a sealed shipping container. I helped Harry build a stand for it with wheels and he has had it ever since. Still a real treat to look at.

Harry is an old "salt" guy he did several cars with Clem Tebow and Don Clark, I think the 32 roadster with the Ardun  that ran 162 back in 52-53 was his.

Rex