Greetings,

 

Well, my neighborhood probably still thinks I'm a lunatic.  I drove out with
my engine test trailer, and got some funny looks.  You'd think they'd be
used to this sort of thing by now :-)

 

The Autoflight redrive looks quite well made, and is 12 lbs lighter overall
than the RD1C that I had before.  As I mentioned though, this one is limited
to 160 HP, so not really what you want for a healthy 2 rotor.  Overall
weight of everything you see (except the trailer and prop) is about 230 lbs.


 

Anyway, I hauled the engine trailer to the airport, and fired it up.  It
actually cranked with little difficulty, but the mixture was way off.
Basically, I ended up running it with the cold start on, but mixture turned
way down.  I'll have to reset everything and start over eventually, but I
just wanted to see it run.  

The bad news is that it's still rough as a cob below 2500 rpm, which is to
be expected with a single rotor and no flywheel.  The test stand has some
flex to it as well, and I spent far too long marveling at it could possibly
jump around that much.  The drive was quiet during all this shaking though.


 

The good news is that it smoothes out above 2500, just like you flipped a
switch.  As you increase rpm, there are still small bands were I heard a
brief light rattle.  I assumed this was the drive, but was much less severe
due to the rubber damper, and tight gear mesh.   It certainly could have
been something else, since there are plenty of things on the test stand to
rattle (including the intake).  This is much better than with the RD1C, but
not as good as I had hoped for.   

I didn't go above 4000 rpm, and never saw more than 105 F on the water temp.
Oil was at 128 F as I recall.  I know I may need some more water flow
through the oil/water exchanger, but this might work OK.  I'll have to get
the temps up farther to find out, and that might require covering up some of
this radiator.   

The prop still has the odd fore and aft tip movement that it had on the
Kolb, so that has not changed at all.  This just has to still be the torque
reversal, but maybe off resonance of the mount.  I took some video of this,
but there was some technical difficulty retrieving it, so I'll have to try
again.  Rats.   

While playing around with the rough point, I found that the engine wouldn't
idle below 2400 anymore, and the throttle was getting stiff.   I was done
anyway, and put the stand away.  When I was looking for leaks (amazingly
none found), I noticed that my telltales on the intake manifold were telling
the tale.  In fact, the intake had all but broken loose due to the shaking.
Partly this is due to my crappy welding, and partly it's due to the shaking.
I'll have to re-weld this, and make it stronger.  I'll also look into some
other way to brace the TB so it's not all being supported by my crappy
welds.  Notice the theme here :-)

 

I've given up on running the engine on the Dominator gyro, and already have
a 582 Rotax for that.  My goal is to decide whether the single rotor will
work well enough to be worth messing with on a plane, then perhaps build a
Zenith 601XL for it.  The main limitation seems to be the low rpm roughness
issue.  I can go as low as maybe 2400 rpm, but that still give me about 970
rpm on the prop.  This is a bit high, but not a complete deal breaker,
particularly on a plane that isn't too slick.  If that's the only issue,
then it will probably be a go.     

Cheers,

Rusty (don't think I can blame the idle problems on my EC-2)