Hi Guy's
I promised to report fairly on this
EWP installation, so here is the bad news. As it's performance up to now as been
very promising, I'm by no means ready to abandon the idea.
I
went to the airport this afternoon to take care of a few minor items, then
decided to pull it out to do another full power (30"MAP, no boost) run-up just
to confirm cooling performance. I only ran it for 4 minutes and satisfied with
the performance of the system, I reduced to an idle to let it cool. Coolant
temps began to drop from 100C (212F) and I turned my attention to other items.
About 1-2 minutes later I scanned the instruments and noticed that the coolant
temp was up to 115C (240F). A quick look at the fuse panel showed the LED
indicating a blown fuse for the EWP. I shut down and quickly changed the fuse,
then resumed power to the EWP without starting the engine. I couldn't
immediately tell if it was pumping as the mechanics for a commuter airline that
I share hangar space with were doing a run-up on a 1900 making too damn much
noise for me to hear the pump. When the temps didn't begin to lower, I put on
some heavy gloves and released the pressure from my cap. Once I had it opened I
was able to add water with a hose, while squeezing the lower coolant hoses in an
effort to burp out some steam and replace with cooler water. At this point
it was very apparent from the lack of flow that the pump was not pumping.
After temps had subsided, I pulled it back inside where it was quieter and
could tell that the pump was not turning at all, however it hadn't blown the new
fuse?
After temps had cooled a little more, I drained the coolant and removed the EWP.
The impellor was seized solid, I couldn't budge it at all. I took it home with
me to pack it up to send back for warranty, but when I got home I took another
look at it and it was no longer seized. I hooked it up with a couple of 1" hoses
and a 5 gal bucket of water. It works fine pumping approx 14 usgal/min. It been
running like that now for almost 3 hours with no problems. I do find that the
motor gets too hot to hold your hand on continuously, but it has been like that
since I first used it. While I don't really like this motor high temp, I realize
it is not uncommon for small motors so I wasn't too concerned. Now I wonder
if it was a factor, combined with under cowl temps from my
run-up.
I'm not certain what to do next. I'm not sure if Davies Craig will warranty this
as it appears to work now, however I'm not certain that I want to fly with this
one either. I'm definitely not prepared to give up on the EWP, but I just want
to make sure I've got a good one for flight. As I've been trying to get my
inspection for several weeks now, and he may be coming up in the next few days,
I'd like to reinstall it for the inspection to get it over with.
I've sent this report to Leon,
hoping that he can check directly with Davies Craig about this and see if they
can send me a replacement, and I will return this one as soon as I receive it.
I'd really hate to turn away the inspector if he wants to come up this
week.