Hello everyone-

As Paul already heard, today was supposed to be the triumphant email
announcing 1st flight of the PPort engine.

Unfortunately, we had a mishap during a landback test.

We're still going through a fault analysis to figure out exactly what
happened, but a couple things clearly conspired to ruin our day.  The engine
ran like gangbusters and accelerated the airplane quicker than expected.
The airplane flew itself up off the runway before the pilot was quite
ready.  Climb attitude pitch was too high, letting the airplane quickly
climb up out of ground effect.  Retarding the throttle caused the engine to
stumble and lose power for unknown reason.  Left wing stalled above ground
effect.

All in all, it was a rather more exciting afternoon than we'd really hoped
for.

The good news is that despite a recipe for disaster, the damage to the
airplane appears minor.  We'll need a new port aileron from when the left
tip of the wing dragged on the ground, and the mains & engine mount will
need some close inspection to make sure they're in as good shape as they
appear to be.  The prop does not look like it hit any dirt.  And the engine
started and ran ran fine during the taxi back to the hangar.  We cycled the
engine though the full rpm range, including max-static when we got the
airplane back & saw no issues.

We have two working ideas on why the engine might have stumbled during the
land back attempt.  First is a fuel-flow issue due to the nose-high
attitude.  We'll test for this by putting the mains on ramps and trying to
bring the engine to full power.  If we have a fuel flow issue, this should
highlight it.  The second idea is that our engine mapping is the cause.
During our ground runs, we have many map addresses which we can never get
to.  Thus we do not have values in these addresses.  Perhaps the engine
entered this address range and thus stumbled.



Mark (Rocky Mtn High)

I think people under estimate the power of these engines.
When Tracy first went to the 2.85:1 PSRU he nearly snagged  the barb wire
fence on the left side of the runway during the first flight. And
that was only 200 HP RX8 side port engine in an RV4.

Like a Gee Bee you got to take it slow :)

A couple of lower power crow hops might be in order until one gets
a feel for it.

BTW Mark's field is 7000 foot density altitude.


BTW I am very glad the pilot and the airplane are OK and
blissfully happy it had so much power to get off the
ground at 7000 foot density altitude so quickly.

If it were a 172 you would be trundling down the runway all day :)

Paul Lamar