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Date: Tue, 31 May 2005 21:29:10 -0500
From: Charlie England <ceengland@bellsouth.net>
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To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Subject: Re: [FlyRotary] A little clarification...
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bbradburry@allvantage.com wrote:

>I am new to be reading this list and I seem to be terribly uneducated and
>stupid.  I know that this is true because I am seriously considering putting
>a rotary in a Lancair Legacy Fixed Gear.
>
>I wish someone would clarify some things for me.
>
>What is the difference in the 4 port and 6 port Renesis, and why should I
>choose the one that I should choose?
>
>What does P Port mean and how is it different from the normal port?  Does
>the Renesis (either one) have a P Port and should it be modified to have one
>put in it?
>
>It seems to me that some of the mods needed to put the rotary in a plane are
>pretty well figured out by you guys...Intake, Exhaust, EC2, Etc..  Some
>other things, cooling for oil and water, still being invented but with some
>idea of what to do.  Other things that seem to be pretty basic and should
>have been solved by the certified industry 100 years ago, like how to run
>gas from the tank to the engine and back, are still being debated like we
>just realized we needed to consider it.
>
>I would really appreciate some help here.  I would like to build a plane and
>fly it.  Low on the build and high on the fly part.  I am not interested in
>doing R&D or starting a business building parts.
>
>There is a lot of discussion about the gentleman who died as to whether he
>had his fuel system set up correctly....How can this be?  How many different
>CORRECT ways to do it are there?  Is the fuel system for the rotary totally
>different from a REAL airplane engine?
>
>I know that this sound really critical, but I don't mean it to be.
>
>Please help!!
>
>Bill Bradburry
>

I think that John answered pretty well; I might expand on his answer to 
the question about fuel system design. This issue isn't limited to the 
rotary, or even to experimentals. Any time the fuel system is more 
complicated than single tank/gravity feed, there's a chance of problems 
with either design or management. A number of years ago here in MS, a 
guy ditched in a big lake on final approach when he selected <off> 
instead of  <both> in a Cessna. Some Cessnas have problems with not 
taking on the placarded fuel quantity. The also have problems with 
trapping water in folds in the same type of bladder that causes limited 
capacity. Quite a few have crashed due to both problems.

There are, at a minimum, dozens of  'correct' fuel delivery systems in 
certified a/c ( & several that aren't so 'correct', even though the FAA 
gave them their blessing).

Most kit type homebuilts have proven fuel delivery system designs if you 
run the recommended engine, but even then you can have problems if, for 
instance, you move an oil cooler from the prototype's location 
(unplanned radiant heat problem). A few Continentals use a 'bypass' type 
fuel pressure regulator & return fuel to the tank, but no certified 
system I'm aware of uses high pressure sequential port injection like 
automotive systems.

I feel your pain on the desire to just build & fly. Realistically, you 
could probably buy a flying example of your favorite design for not much 
if any more money than you will spend building. I'm currently flying my 
4th purchased homebuilt & all were purchased for less than the parts 
would have cost me to build them. I'm currently building because I want 
the satisfaction of doing it myself & I'm accepting the time penalty.

As far as the rotary installation goes, you just have to evaluate 
whether you are willing to invest the extra time to do an alternative 
engine development program (each installation is unique in some way) and 
much more importantly, try to honestly evaluate whether you have the 
necessary skills to create a 'safe & effective' installation. That might 
be the hardest thing for a pilot to be objective about.

Charlie
(*really* want an alternative to the Lyc, & trying to do that honest 
evaluation)