ericmpmail-rv(at)yahoo.co
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 Posted: Mon Jul 31, 2006 9:49 am Post subject: OSH Engine Info - Mistral and V + yet another OSH engine sum |
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Mistral:
All injected Mazda's use dual injectors. The smaller
injector is for idle to mid-power. The secondary comes
on for higher power. Reason for two is single injector
does not have the dynamic range for idle to full
power. Downside, is if you loose one, the other cannot
take up the slack as duty cycles above 8%. The other
reason for two injectors per rotor is there are two
side intakes per rotor.
Dual ignition is also stock Mazda. The leading plug
does the majority of the work and the trailing plug is
mostly for emissions (it is shielded). If you set
timing equal for power, it is still not a full backup
due to the shielded spark and location.
2 rotors with turbo charging is not as attractive as
rotors and no-turbo charging. Normally aspirated
-rotor block weight is ~ 24 lbs and with accessories
should be comparable to IO-54 for ~ 2-25 HP.
Rotary exhaust is ~ 7+ deg and is very hard on
turbo's. Car systems use massive cast iron manifolds
to manage heat.
V: This is the rotax water cooled engine spin off.
I may have the name wrong. Talked with them for
awhile, they are focusing on OEM applications and
won't look at experimental market for 4-5 years. For
RV-, V and V22 engines (non turbo charged) are
going to be too heavy as weight is ~5+ without
exhaust, cooling, etc. Price is more than 5k and less
than k. (Didn't disagree when I said 8k).
BSFC a respectable .445
For 8k you could build up the world's best IO-54
with full FADEC, flow matched, dyno tested, etc. and
still have 's of thousands for avgas....
Eggenfellner and H6: I looked at H6 for RV-
previously, but did not see Jan's talk. Max HP is near
lower range of RV- requirement. Supercharger's tend
to lower efficiency than turbo. Both would require
aggressive intercooling for an H-6 as stock compresion
ratio is ~ .5:. By most measures, this is not a
good candiate engine for turbo charging and I believe
subaru has also never turbocharged it. Better target
would be their low compression 4-cylinders.
After further review, my OSH assessment is:
- Want to fly in 26? Lycoming new or rebuilt
- Willing to wait to 27? ECi IO-54 clone or
Superior XP-54 might be options.
- Do it yourself: Mazda -rotor conversion with Tracy
drive and controller, Conversion concepts mount and ~
4K (K engine, .2 rebuild, 2.8 drive, .8
controller, .7 mount, intake/exhaust/rad)
- Hanger flying: Innodyn, Eggenfellner, Mistral, etc.
Reason for hanger flying for some of those packages is
although they might work, the cost to benefit ratio is
not compelling (IMHO).
Eric
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