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
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--> Engines-List message posted by: "Gary K" <garyk2@cox.net>
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" <NeilsenRM05@comcast.net>
Subject: Engines-List: New Member
> --> Engines-List message posted by: "Richard & Martha Neilsen"
> <NeilsenRM05@comcast.net>
>
> 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
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--> Engines-List message posted by: "Richard & Martha Neilsen" <NeilsenRM05@comcast.net>
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" <garyk2@cox.net>
Subject: Re: Engines-List: New Member
> --> Engines-List message posted by: "Gary K" <garyk2@cox.net>
>
> 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
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| Subject: | Re: Crossover exhaust |
--> Engines-List message posted by: Charlie England <ceengland@bellsouth.net>
DEAN PSIROPOULOS wrote:
>--> Engines-List message posted by: "DEAN PSIROPOULOS" <dean.psiropoulos@verizon.net>
>
>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
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| Subject: | Re: Crossover exhaust |
--> Engines-List message posted by: "Archie" <archie97@earthlink.net>
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" <ceengland@bellsouth.net>
Subject: Re: Engines-List: Crossover exhaust
> --> Engines-List message posted by: Charlie England
> <ceengland@bellsouth.net>
>
> DEAN PSIROPOULOS wrote:
>
>>--> Engines-List message posted by: "DEAN PSIROPOULOS"
>><dean.psiropoulos@verizon.net>
>>
>>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
>
>
>
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