REFLECTOR: A question about engines

[Andy Millin]

Hi Randy,

This a dangerous question.  Actually, it is more of a dangerous thing to try
to answer.  Choice of engine can be as personal as the choice of standard or
XL, fixed or retract.  There is no wrong answer, just what is right for you
based on your wallet, engineering skills, and desire to experiment.  I found
very intense passion and strong opinion when looking at engines.

I'm not sure that I have .02 cents worth, but I have studied the power plant
trying to find my own answer.

I found people who told me (at the Velocity get together at OSH) that if I
put an automotive engine in my airplane that they didn't want me to fly over
their house (yes, I was stunned).  I found those that had put in the rotary
and couldn't be happier.  It is a great engine.  Others said that if it
wasn't certified they didn't even want to talk to me.  Deltahawk isn't
certified yet.  The Superior XP-360 isn't certified.  Running a GM
alternator is not certified.  Kinda rough to be told that if you don't have
a yellow tag for everything then you are a cheap bastard and are a safety
hazard to everyone.  Engine research can be rough.

It was not a pleasant experience.  I'll go out on a limb and share what I
found.

I too looked at the automotive option.  When I started the kit I was certain
I would have an aluminum V8.  After more research, I came to the same
general conclusion as Ronnie.  The automotive engine was a reliable option.
However, there really isn't a dollar savings.  After making the
modifications to make it an aircraft engine and developing the installation,
you will have put plenty of cash into it.  Also it might be hard to find an
installation to copy from.  You will probably be on your own for
development.  You could spend three months just making a new cowl.  Jim
Sower's installation is marvelous.  He did it right.  Better than right, it
is fantastic.  He also spent the time and the money.  Great if that is your
cup of tea.

Velocity has developed installation packages for the most installed aircraft
engines.  Reasonably priced, well understood, and you can get great tech
support from the factory.

When considering the engine, I looked at HP.  I wish that more was always
better.  Unless you make some modifications to the airframe, your useful
load can change with more power but your VNE will not.  200 kts is it.  Yes,
there are guys that have gone well beyond that, but I don't want to be that
pilot.  The XL/RG with the 260 hp and the right prop can cruise at 190 kts.
Wes Rose was flying with the 300 hp Lycoming and he also cruised at 190 kts.
My conclusion was the extra hp would be there for take off and climb
performance.  The need for this might be based upon your personal use.  Will
you need to get out of short strips, or possibly high DA?  The extra HP
isn't free.  It costs more and generally weighs more.

I looked at the Lycoming IO-540 and the Continental IO-520 and IO-550.  I
don't know of a database or other reference that gives a compare and
contrast on each engine type.  What I had were some great folks on the
reflector (Rob Johnson, who I wish was still on the reflector) and my
technical counselors.  I feel like I should put a million disclaimers here.
This is what I found, and I'm sure others have different experience.  The
Continental engines in general have a harder time making it to an 1800 hour
TBO.  For the IO-520, I spoke with three people who had significant
experience with the engine and said it was not uncommon for the engine to
need overhaul after 1200 hours.  Even harder if it is turbo charged.  (Might
be hearing from Scott Derrick on this one... )

I also asked about the IO-550.  The engine can be hard on the cylinders and
it has been known to need overhaul at 500 hours (from factory new).  I'm
sure people have gotten to TBO.  My conclusion was that engine could be even
more expensive to buy and own that I thought.

Then came the Lycoming option.  Angle valve, 300 HP or parallel valve 260.
I asked quite a few people.  Last year at OSH I must have stopped at half a
dozen engine rebuild shop booths.  I explained that I am not a mechanic and
don't know much about aircraft engines.  They were super nice and answered
my questions.  What is wide deck?  What is narrow deck?  What is angle
valve/parallel valve?  What difference does it make?  Why should I care?
What do YOU think of the engines?  The general answer was that if I didn't
need 300 HP then I might be better off with the 260 HP engine.  Their
experience was that the engine was very reliable and had a good chance of
making it to TBO.  The 300 HP engine had more problems and would probably
cost more to own.

Disclaimer.  Disclaimer.  Disclaimer.  Disclaimer.  Disclaimer..... Your
mileage might vary. Your mileage WILL vary.   The people you talk to can and
probably will have contrary opinions.  This is what I gathered from the
people I spoke with.  I have never owned one of these engines.  I am not an
expert.  Listening to me is probably dangerous.  :-) 

I would ask you to look at the requirements you had set down for the
airplane you wanted.  How fast do you want to cruise?  What kind of takeoff
performance do you want or need?  What useful load do you want to carry?
What range do you want?  How much do you want to spend?  How much do you
want to experiment?  How much do you want to engineer?  Do you enjoy
tinkering as much or even more than you like flying?  How important is it to
you that your aircraft be unique?

I'm sure you will get a lot of good, practical advice from others on the
reflector.  I opted for the 260 HP Lycoming IO-540-C4B5.

Best,

Andy




-----Original Message-----
From: reflector-bounces at tvbf.org [mailto:reflector-bounces at tvbf.org] On
Behalf Of Randy Wharton
Sent: Friday, February 04, 2005 7:23 AM
To: reflector at tvbf.org
Subject: REFLECTOR: A question about engines


I bought my XL kit last summer after taking the company XL-5 for a spin and
loving it. 271TC has a Continental 550 on it, and I've just kind of planned
on putting the same on mine. But I'm really getting daunted by the $40-45000
price tag, especially when I hear guys talking about Chevy V8s, Subaru's
etc, even though I know that water cooling adds a new level of complexity,
not to mention weight to the plane.
 
I know that if I throw the question out there about what people recommend,
I'm going to get a ton of different answers, because everyone probably loves
the powerplant they have, but I'm not committed to any particular one at
this point. I'm quite sure that the Conti 550 is the premier powerplant,
assuming that a Conti 550 is in the budget, but what I haven't found is a
source (pamphlet or article, or something like that) that lays out the pros
and cons . As with any engineering task, there are advantages and
disadvantages that have to be weighed according to how the engineer wants to
play the game, and much of it comes down to a personal choice.
 
Is there a single source for information on the tradeoffs between
Continentals, Lycomings, Chevy's, Subarus, Mazda's, etc? I'm guessing
probably not. But in any case, I'd welcome a discussion on what the
considerations are for various options. I know it's a nebulous question, so
I'm ready for a massive download of information. Thanks!
 
Randy Wharton
N248RB XL-RG
http://clik.to/velocity