---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Sun 11/20/05: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 05:41 AM - Re: New Member (Gary K) 2. 06:54 AM - Re: New Member (Richard & Martha Neilsen) 3. 06:56 AM - Re: Crossover exhaust (Charlie England) 4. 04:54 PM - Re: Crossover exhaust (Archie) ________________________________ Message 1 _____________________________________ Time: 05:41:05 AM PST US From: "Gary K" Subject: Re: Engines-List: New Member --> Engines-List message posted by: "Gary K" what kind of prop? i'm assuming 3-blade on a pusher? what's the reduction ratio? how many hours on the drive? thanks, gary ----- Original Message ----- From: "Richard & Martha Neilsen" Subject: Engines-List: New Member > --> Engines-List message posted by: "Richard & Martha Neilsen" > > > Hey all > > I'm a new member of the engines list. I have been a long term member of > the Kolb list. I have a redrive VW powered Kolb MKIIIc. The engine is > basically a 2180 cc dunebuggy engine with a Valley reduction drive and a > three bladed 72" Power Fin Model F. When I originally flew my Kolb I had a > 2180cc Great Plains direct drive engine on it. The original engine didn't > have enough thrust for my plane to fly it with a passenger. Since > switching to a redrive VW I have enjoyed a much better climb, faster > cruise, lower engine temps, lower fuel consumption, and yes it is now a > two passenger airplane. The only down side is a bit more vibration. > > Rick Neilsen > Redrive VW powered MKIIIc > > > ________________________________ Message 2 _____________________________________ Time: 06:54:33 AM PST US From: "Richard & Martha Neilsen" Subject: Re: Engines-List: New Member --> Engines-List message posted by: "Richard & Martha Neilsen" Gary For the prop see below.... The reduction ratio 1.61 to 1 and I have 160 hours on the drive. Rick Neilsen Redrive VW powered Kolb MKIIIc ----- Original Message ----- From: "Gary K" Subject: Re: Engines-List: New Member > --> Engines-List message posted by: "Gary K" > > what kind of prop? i'm assuming 3-blade on a pusher? what's the reduction > ratio? how many hours on the drive? > > thanks, > gary > a Valley reduction drive and a >> three bladed 72" Power Fin Model F. When I originally flew my Kolb I had >> a >> 2180cc Great Plains direct drive engine on it. The original engine didn't >> have enough thrust for my plane to fly it with a passenger. Since >> switching to a redrive VW I have enjoyed a much better climb, faster >> cruise, lower engine temps, lower fuel consumption, and yes it is now a >> two passenger airplane. The only down side is a bit more vibration. >> >> Rick Neilsen >> Redrive VW powered MKIIIc ________________________________ Message 3 _____________________________________ Time: 06:56:56 AM PST US From: Charlie England Subject: Re: Engines-List: Crossover exhaust --> Engines-List message posted by: Charlie England DEAN PSIROPOULOS wrote: >--> Engines-List message posted by: "DEAN PSIROPOULOS" > >Question on exhaust: > >Parallel valve Lycoming 4 cylinder engine. Is there a reason the front two >pipes have to cross over before they go out the cowling? Everyone says that >Lycomings have to have an oil cooler because the oil runs hot. Gee I wonder >why...two hot exhaust pipes run right past the front of the oil sump and >dump gobs of heat into the oil (in addition to the rear cylinders heating up >the sides of the sump)!!! So why not trash this exhaust pipe configuration >(the crossover) and go to a simple 2 into 1 set up on each side of the >engine? Just bring the two pipes together off the same side and dump it out >the cowling without crossing over in front of the oil pan. A fellow >Lancair 360 builder (who also used to work on race boats for a living) built >his own exhaust like this from Aircraft Spruce parts. Airplane isn't flying >yet but I certainly see his logic in doing it. Another fellow Q200 builder >did the same thing with his 0-200 Continental engine and says there has been >a noticeable difference in under-cowl temps. I can't believe this hasn't >come up before, anybody know the answer? Is there a good reason the exhaust >has to crossover? What wives-tail or urban legend says the exhaust has to >crossover? > >Dean Psiropoulos >RV-6A N197DM >Installing exhaust > As Kevin Horton hinted on another list, the crossover exhaust is there for 'free horsepower'. When you feed exhaust pulses from the same side of an a/c engine into the same pipe, they each 'fight' the other's ability to exit its cylinder. It's not urban legend; it's normal tuning practice on piston engines. The best tuning comes with a 4-into-one exhaust, but that's pretty hard to implement inside a cowl. It's also very hard to install pipes in an airplane long enough to properly tune the pressure pulses at the very low rpm of an a/c engine. The x-over system is considered the best compromise to keep the pulses from fighting each other while keeping the system as light & compact as possible. There's a lot of info out there about the subject; if you read it all you'll never fly the -6. ;-) Charlie ________________________________ Message 4 _____________________________________ Time: 04:54:32 PM PST US From: "Archie" Subject: Re: Engines-List: Crossover exhaust --> Engines-List message posted by: "Archie" You pretty much hit the nail on the head, Charlie. I have disseminated, and written articles on exhaust tuning which when describing the mathematical pros and cons of various designs, only tend to confuse the layman. Archie ----- Original Message ----- From: "Charlie England" Subject: Re: Engines-List: Crossover exhaust > --> Engines-List message posted by: Charlie England > > > DEAN PSIROPOULOS wrote: > >>--> Engines-List message posted by: "DEAN PSIROPOULOS" >> >> >>Question on exhaust: >> >>Parallel valve Lycoming 4 cylinder engine. Is there a reason the front >>two >>pipes have to cross over before they go out the cowling? Everyone says >>that >>Lycomings have to have an oil cooler because the oil runs hot. Gee I >>wonder >>why...two hot exhaust pipes run right past the front of the oil sump and >>dump gobs of heat into the oil (in addition to the rear cylinders heating >>up >>the sides of the sump)!!! So why not trash this exhaust pipe configuration >>(the crossover) and go to a simple 2 into 1 set up on each side of the >>engine? Just bring the two pipes together off the same side and dump it >>out >>the cowling without crossing over in front of the oil pan. A fellow >>Lancair 360 builder (who also used to work on race boats for a living) >>built >>his own exhaust like this from Aircraft Spruce parts. Airplane isn't >>flying >>yet but I certainly see his logic in doing it. Another fellow Q200 >>builder >>did the same thing with his 0-200 Continental engine and says there has >>been >>a noticeable difference in under-cowl temps. I can't believe this hasn't >>come up before, anybody know the answer? Is there a good reason the >>exhaust >>has to crossover? What wives-tail or urban legend says the exhaust has to >>crossover? >> >>Dean Psiropoulos >>RV-6A N197DM >>Installing exhaust >> > > As Kevin Horton hinted on another list, the crossover exhaust is there > for 'free horsepower'. When you feed exhaust pulses from the same side > of an a/c engine into the same pipe, they each 'fight' the other's > ability to exit its cylinder. It's not urban legend; it's normal tuning > practice on piston engines. The best tuning comes with a 4-into-one > exhaust, but that's pretty hard to implement inside a cowl. It's also > very hard to install pipes in an airplane long enough to properly tune > the pressure pulses at the very low rpm of an a/c engine. The x-over > system is considered the best compromise to keep the pulses from > fighting each other while keeping the system as light & compact as > possible. > > There's a lot of info out there about the subject; if you read it all > you'll never fly the -6. ;-) > > Charlie > > >