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Some days are bad, some days are good and some days
have a bit of both. I went out to the hangar around 1000 to hook up my new
digital Fuel Monitoring system. The Bad news is it read the first
pulse and froze (more on this later), so I was a bit discouraged, though it
might be the EFI pulse might be dirty compared to the laboratory pulse I had
been using to test the unit. Figured I would have to haul my oscilloscope
out to the hangar tomorrow to see what the EFI pulse train actually looked
like.
But, while scratching my head, my two new next-door
hangar neighbors showed up to fly their Kobe Ultralight. These are both
older airline pilots (one retired) who decided to fly utralights - without any
lessons of course. But, nice guys just the same. The first flight
made about two weeks ago ended up with one of the landing struts bent from
dropping it in a bit high.
Today they were back for another try. Number
one takes off and it sounds like to me that he is not making anywhere near full
power. He flys around the pattern a couple of times making passes at the
runway and finally sets it down with about a 2 foot drop - not too pretty but
respectable. He then is trying to talk his buddy into taking it up - as
they are discussing how it handles, I over hear him make a comment that at full
throttle the power fades and you have to pull it back to around 4500 rpm ( the
max he has reached) to get the power back.
Well, I know nothing about rotax engines but that
sounded like fuel starvation at higher power settings. I asked what type
fuel pump they had and it turns out it is a diaphragm type driven by
pulsation's from the engine via a tube. Sure enough as I looked it over, I
found that the tube from the engine to the pump that provided the suction pulses
to work the diaphragm was crimped almost shut near the pump where it was
difficult to see. Clearly not a good condition, I point this out to them
and they rapidly put on a new tube.
Fired it up and got almost 6000 rpm on the
ground. Took off and look like he was going straight up - a marked
difference in performance. Don't know if this condition would have
resulted in an accident - but clearly not a good situation.
So they day turned out not so bad after all.
Then I got home hooked up the EFI monitor and it wouldn't work there either
!!!!!
Turns out I changed ONE line of code this
morning before taking it out and had not bothered to check it on the
laboratory pulse meter. I mean it was a very simple change {:>).
It didn't work on it any better back at home than it did on the
aircraft. But, it was a relief to know it was a simply code screw
up. Eliminated that line of code and all is back working.
So what started out to be a bad day (relatively
speaking) ended up pretty nice.
Ed
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