Matt Prather wrote:

Hi Paul,

Not sure any of you are watching John Slader's progress with his turbo 13b
powered
Cozy..  It sounds like he's starting to get the performance one might
expect from such
a setup.   Here's a link to his flight test page.

http://www.canardaviation.com/cozy/chap29.htm

He's had to sort through a variety of problems thus far.   Here's some
text from his
most recent testing.  Runs smoother at 6000rpm than 5000rpm.  Hmmm.
That's not,
totally unexpected, I suppose.  185kts indicated at 11500' 
is about 226kts true.  Not bad.

"Once at the top of the climb I let her settle down a bit, then gradually
moved the throttle forward. So far my max rpm has been 5700. As I passed
through 5800 with 36 MAP I noticed something interesting. The relatively
minor vibrations I'd gotten used to just smoothed out. At 5900 rpm and 38
MAP it was even smoother. Cool. I could get used to this. By this time I
had about 165kts indicated and 6000 rpm the engine was simply purrrring
like the kitten she's supposed to be. I checked intake temp - 134. I
richened the mixture a little and nudged the throttle a bit more. She kept
on coming. I backed off - ok chickened out - at 6100 rpm and 185 kts
indicated with a 44 MAP. GS showed 234kts (269.2 mph to save you working
it out), and no, I didn't measure it going the other way.

Throttling back to 5000 rpm and 140 IAS brought back the minor vibration
I'd gotten used to, but I wanted to do some hours today, not just burn off
the gas. As I headed over to Pahokee I noted 11.4 GPH on the now
calibrated EM2 with 8 bars of mixture. The guys on fly-rotary were talking
only yesterday about running on 2 or 3 bars, or even less, but they're not
turbo. I tweaked the mixture a tiny bit toward lean, and was rewarded with
10.5. Another tiny tweak - man this is sensitive - and I had 9.4 gph with
no noticeable change in engine rpm. EGT at this point was 1640. I settled
for that and cruised the 38 miles to overhead PHK in about 10 minutes.

I did a wide circle over Lake Okeechobee, considered taking a trip North
to F45 again, but decided on heading back toward LNA. I gave her another
bit of a high speed run on the way back with similar results. There's
definitely a noticeable reduction in vibration as I pass through 5900 rpm.
I think some dynamic balancing is in order, but first I'll send the prop
back to Clark for "final finishing" and see how it is when he's done with
it. Since I'm getting 6100 I may not want to cut it back much, if at all.
I'd rather live with reduced take-off and climb (where higher power may
get me into cooling problems too) in exchange for high speed cruise. But,
then again, if I cut it back a bit I might be able to do the same with
less boost. This would be better - right? By the way, perhaps I should
mention that the manual wastegate was wide open for the entire flight."

Regards,

Matt-

I admire his perseverance. He could easily win the Sun 100 mile cross country race
$750 Everett Hatch Memorial prize in April if he entered.

I have always maintained we have just scratched the potential of the Mazda
rotary engine. For thirty years people, Dave Garber excepted, have been
too conservative when applying the rotary engine to aircraft use.
The rotary engine is head and shoulders above ANY piston engine when
it comes to shear robustness while generating ungodly amounts of HP.

Paul
 
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