Hi Philip,
Yes, most everything that applies to the earlier 13B applies to the
Renesis (it IS a 13B, says so right on the rotor housings), with a few
exceptions (long subject for an email).
You are correct in your concern about weight. The rotary IS very
light, but compared to what? The actual installed weight will depend
a lot on your choices (literally dozens of them). Overweight installations
get there 1 ounce at a time. If you pay attention to weight, the rotary
can come in at the same weight as an O - 320 Lyc. My RV-4 empty
weight is (or was when I weighed it 13 years ago) 948 lbs which is at the
low end for RV-4s. My FWF weight on the current installation (Renesis)
is ~ 325 lbs. I have seen rotary installations that I estimate weigh
almost 100 lbs more. Details matter.
I think the rotary is about the only auto engine that is at or better than
standard aircraft engines for power to weight ratio.
Power? Only facts I can offer are my Sun 100 race results. The
closest O - 320 powered RV in the race was more than 10 mph slower than my
217.51 MPH average speed (2004 race). I would like to see more Subies
enter! Bob (Oldfield?) entered his turbocharged EJ-22 powered
RV-4 in 2002 and finished at 207 MPH average speed. He gave up on the Sube
after his 4th engine threw a rod. The first 3 failed for various
other reasons.
Cost? That varies as much or more than weight. I think George
Graham gets the low cost award. His total FWR (pusher) cost was less than
$2000 best I recall. He has since changed his redrive (was a Mazda
transmission in 2nd gear) to an RWS drive (which doubled his installation cost :
)
Tracy (must get back to work on RV-8)
----- Original Message -----
Sent: Friday, October 13, 2006 11:44
AM
Subject: [FlyRotary] newbie
Hello all,
I'm new to this group. I'm at the
beginning of an RV-9A construction (working on rudder now). As I'm sure
everyone does at the beginning, I've been spending a lot of time thinking
ahead about hte choices I'll have to make later on. I'm very interested
in the Rotary option, and have tonnes of questions. A few that come to
mind initially:
1) I would probably go with a 4-port Renesis.
Would most of the conversion information that is available for the older RX-7
engines be applicable to the new engines? Or would I have to solve a
bunch of problems from scratch, without being able to draw much on the
experience of others who have done older 13B conversions?
2) One of my
biggest concerns about auto-conversions is weight. The rotary
enthusiasts claim it has very low weight. The anti-auto-conversion
people point out that much of the extra weight in a conversion comes from all
the extra stuff you have to modify or add to make it work properly. What
would the real final installed wieght of a renesis on an RV-9 be, compared
with an O-320 installation (i.e. not just engine weight, but total installed
weight)?
3) Power - Subaru auto conversions are popular in RVs.
However, people put in Subie engines that are advertised to be 165 HP, but at
the prop they develop much less power, and a popular complaint is that these
aircraft end-up being slow, and under-powered. What is the case with a
Rotary? If I put a Renesis on an RV-9A, would this give me as much power
as an O-320? Do I need a CS prop? My strong preference is to use a
FP prop.
4) Money - assuming I buy a remanufactured engine from Mazda
or somewhere else (i.e. buy a remanufactured engine and not overhaul an older
engine myself), how much money will I really save, after you account for all
the accessories and modifications?
Thanks for any advice you folks can
offer on these questions!
Phil Kaye
___________________________________
Phillip Kaye
RV-9A
Ser# 91440
C-FUNC(reserved)
www.c-func.com
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