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Bryan,
I went with the 20B because it was closer to the weight of the IO-550 my
a/c was designed to use. Of course, I could have added a bag of
cement to the nose too. Also, although the 13B is smoother than its
reciprocating counterparts, the 20B is even smoother as it fires three
times per rev. instead of two. And if you're going to carry the
weight of the turbo and related hardware, I would prefer to go with an
extra rotor instead.
One other consideration... if a 13B looses a rotor, you've lost over half
of your power, but if a 20B looses a rotor you've only lost about 1/3 of
your power. That's still a bad thing, but not quite as bad.
The exhaust sounds neater. (personal preference) Sort of like
the difference between a V-6 and a V-8.
And... its sexier. (at my age I need all the help I can
get)
Yes, it costs more, but a lot less than a certified engine. And
there are fewer off-the-shelf parts available for the 20B.
Mark S.
At 07:55 PM 6/1/2004 -0700, you wrote:
Hi
all,
I have been lurking in the background trying to
learn what I can. I intend to use a rotary in the BD-4 I am
currently building. It will be some time before I actually need an
engine but there are some questions I have regarding the use of a 13b vs.
a 20b.
1: What is the difference (average
installation) between the installed weight of the two?
2: What is the cost difference in 13b NA,
13b turbo, 20b NA?
3: Do Tracy's components work with the
20b (EC2 and RD-1C)?
The reason I ask these things at this point is
that I am (as most) building on a budget. I also am at a stage that
I need to make a decision about whether or not to extend the fuselage on
my plane. The back seat in a BD-4 has practically no leg
room. I am looking at extending the fuselage to get 5"-6"
more inches leg room in the back seat. This would work if I can
afford a 20b to counter the change in CG that comes with the fuselage
extension. And there is also the fact that more power is always a
good thing.
Thanks in advance for any help
given,
Bryan
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