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  • #16
    Re: 232 Engine

    Here's an interesting tidbit I pilfered from an automotive forum where a Mike Brown era crew member was discussing problems related to this engine:

    "It is in fact an 18 cylinder Wright R-3350(-93) engine with mechanical fuel injection. After a $175k engine overhaul last year, we replaced two more sets of pistons/cylinders (@ $54k/set) due to detonation. The net result was a racer that could not race and a pile of unserviceable parts. The boss is still a little pissed! The solution looks like it could be had with a relatively small number of (cheap) parts. I was wondering if the solution was as simple as a knock-sensor. Unfortunately there is relatively little data available on what a knock-sensor does and what the wave-form of a knock looks like. I have read some data that suggests that the knock looks like a spike in the 3kHz region. The article did not mention the number of cylinders in the test engine. Is the phenomenon independent of the number of cylinders? I am trying to figure out what the 'event' looks like so that I can 'capture' it in some form when it shows up.


    Wow! there are so many good ideas I do not know where to begin. To "flesh-in" the detail ... here goes ...
    The 3350-93 is not the same engine that appeared in the B-29. The -93 is mechanically fuel injected (like the Daimler DB-603) whereas the the bomber motor was carbuerated (but still fed a supercharger). The fuel in WWII was typically 145/160 octane (purple color), enhanced primarily with benzene. The fuel consumed for normal flying in the race plane is 100LL which is adequate for the task. For racing, we use the VP Racing Fuel with a performance number (octane) of around 160 (at $6.00/gallon - ouch!). This gets "hot-rodded" with the addition of CI3, a very high manganese solution which the Air Force abandoned in the 1960's because it was too hard to mix in the normal fueling process. This yields a performance number around 200. This allows manifold absolute pressures (MAP) in the range of 65 to 100 in-Hg. This high MAP increases (virtually guarantees) the problem of detonation; which is the reason I got on this board. We are currently using anti-detonation injection (ADI) to combat the detonation. The ADI is a mixture of methanol and water injected into the induction system downstream of the supercharger. The latent heat of evaporation of the ADI sucks the extra heat out of the combustion charge before it enters the cylinder. The problem with this engine installation is that you cannot hear a knock like you can in my '84 VW Rabbitt. So we are back to figuring out how you can listen for these events."

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    • #17
      Re: 232 Engine

      Keep it coming! I love learning about internals of these beasts. If you could somehow use knock sensors, then some sort of electronic ignition would have to be used instead of the mags - or are these guys already using this?
      1960 Piper Comanche

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      • #18
        Re: 232 Engine

        Did Brown ever show up with a trailer of engines or was he a one engine for the week kind of guy.
        Random Air Blog

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        • #19
          Re: 232 Engine

          Did 232 (Mike Brown era) run the 3350 with PRT's and Fuel Injection on a slow nose case?
          "Lighten Up Francis....."

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          • #20
            Re: 232 Engine

            Originally posted by Samuel View Post
            Did Brown ever show up with a trailer of engines or was he a one engine for the week kind of guy.
            Mike had one engine to race with. It was a Slow Nose Case, Fuel injected, without PRT's from what I have read.

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            • #21
              Re: 232 Engine

              Originally posted by boomtown View Post
              Did 232 (Mike Brown era) run the 3350 with PRT's and Fuel Injection on a slow nose case?
              Mike had one engine to race with. It was a Slow Nose Case, Fuel injected, without PRT's from what I have read.

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              • #22
                Re: 232 Engine

                Originally posted by boomtown View Post
                Did 232 (Mike Brown era) run the 3350 with PRT's and Fuel Injection on a slow nose case?
                The picture included with my previous post shows the last Mike Brown era engine after it was ripped out. So yes it did, but PRTs were removed...
                Last edited by RichH; 09-10-2014, 05:55 PM.

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                • #23
                  Re: 232 Engine

                  The only attempt at running a PRT equipped 3350 in an air racer was the "Mr Awesome" Yak.

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                  • #24
                    Re: 232 Engine

                    Originally posted by stuntflyr View Post
                    The '80's Alameda gold dyno engines were stock -26's with the EA-2 nosecase. They are very competitive with that set-up, especially at lower elevations like Bakersfield. The Fifi engine was very similar. The slow nose case allows higher rpm, and hence BMEP, turning the propeller at it's best efficiency rpm.
                    Chris...
                    Chris, the only stock -26W engines we ran were the 1969 and the 1970 engines. After the engine failure at Reno in 1985 we bought a stock -26W engine and put a 988TC18EA-2 nose case on it. For that year, not as a solution. The Bear engines starting in the 1971 era involved basically an R-3350-36W power section with an EA-2 nose case, and a -26WC blower. Later on in the early 1980s we added the spacer and started using the three planetary drive from the R-3350-42.
                    John Slack

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                    • #25
                      Re: 232 Engine

                      9/8

                      "Lighten Up Francis....."

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                      • #26
                        Re: 232 Engine

                        Originally posted by BellCobraIV View Post
                        Chris, the only stock -26W engines we ran were the 1969 and the 1970 engines. After the engine failure at Reno in 1985 we bought a stock -26W engine and put a 988TC18EA-2 nose case on it. For that year, not as a solution. The Bear engines starting in the 1971 era involved basically an R-3350-36W power section with an EA-2 nose case, and a -26WC blower. Later on in the early 1980s we added the spacer and started using the three planetary drive from the R-3350-42.
                        Glad to see you still perusing the minefield.

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                        • #27
                          Re: 232 Engine

                          Hi John!
                          Thanks, I didn't know exactly. Hope you're well.
                          Chris...

                          Originally posted by BellCobraIV View Post
                          Chris, the only stock -26W engines we ran were the 1969 and the 1970 engines. After the engine failure at Reno in 1985 we bought a stock -26W engine and put a 988TC18EA-2 nose case on it. For that year, not as a solution. The Bear engines starting in the 1971 era involved basically an R-3350-36W power section with an EA-2 nose case, and a -26WC blower. Later on in the early 1980s we added the spacer and started using the three planetary drive from the R-3350-42.

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                          • #28
                            Re: 232 Engine

                            Originally posted by boomtown View Post
                            9/8
                            Textbook.

                            Dude, you've got a hell of a steady hand. Nice work.
                            You'll get your chance, smart guy!

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