|
Gaylen,
Glad to hear your fuse problem was resolved. I have flow
over 2000 hours in military aircraft which (at least in my day) never had
anything but circuit breakers. So you can considered me biased toward
CBs. There was more than one occasion a temporary
condition would cause a CB to pop, which I was able to reset and regain use of
the equipment - clearly can not do that with a fuse.
Despite the less weight and cheaper alternative of fuses, I
(personal viewpoint) never use fuses in any flight critical systems - I do use
fuses in those which are not flight critical. Nothing against fuses,
except there is no second chance. If the condition persists then of
course, you do not want to keep resetting the CB - but, if a temporary overload
condition - you may keep flying.
I have found that it is not uncommon to find (especially in an
automobile with a few years on it) that intermittent electrical problems could
often be traced to corrosion of the fuse holder blades. 90% of the time , just
pulling the fuse and sliding it back in would scrape off enough corrosion that
good metal contact would be made and you were back in business.
The ignition models pull a lot of current and in aircraft use
are driven harder than in automobile usage. The leading module (stock Rx-7
ignition) actually blew a resistor in its base due to this loading (same
happened to Tracy Crook and a couple of others) and possible elevated under cowl
temperatures early on. So I replace that resistor with a higher wattage
one and have now been flying for 9 years with it.
I recently found that my engine would not start - no
spark. I traced the problem to a Molex connection that apparently had not
been making good contact between pin and socket. This had apparently
caused arcing and eventually ended up creating sufficient resistance that large
amounts of current could not flow without a large voltage drop across the
pin. So without a load, if you measured the voltage on each side of
the plug, you got 12.6 volts. But, if you turned the ignition on the
voltage would drop to below 9 volts.
Good to hear you got your cooling resolved, give us a further
report on that (with photos) when you are inclined - we are always interested in
approaches that solving any cooling problem.
Best Regards
Ed
----- Original Message -----
Sent: Friday, November 30, 2007 7:57
AM
Subject: [FlyRotary] Re: Gaylen Lerohl
Update???
Doug,
I finished my first annual condition inspection last month. I have
about 80 hours on it now. I had only one major issue. I used fuses
to protect my wiring. I had an engine stoppage due to a fuse protecting
the coils apparently arcing and eventually building up enough oxide to prevent
current flow. I rewired my flight critical bus using robust aircraft
circuit breakers. The fuse panel appeared normal - no apparent problems
with it and the fuse looked good. It gave me a headache troubleshooting
it! I finally discovered the tiny corroded spot on the fuse. I'm
still using fuses on the non-critical bus.
I did a cleanup on the lower cowl and improved airspeed
considerably. Originally my radiator (mounted horizontally under the
engine) was open to the air. At high speeds a rumble was apparent.
I have since extended the cowl to enclose the radiator. Now I can make
176 KIAS at 3500'. That is about the top speed Van says one should get
from a 160HP engine.
The engine is running good and I have halted improvement projects until
warmer wx in the spring. It's still a work in progress! The
airplane flys well.
Our chapter organizes impromptu fly-outs whenever the wx looks
good. Last Sunday four airplanes went up to Brainerd for one of those
$100 hamburgers! We're trying to keep the rust out of them!
Gaylen
----- Original Message -----
Sent: Thursday, November 29, 2007 6:24
PM
Subject: [FlyRotary] Gaylen Lerohl
Update???
Gaylen:
What is up with your aircraft? How many hours do you have on it
by now? Are there any issues with it you have had
to address? What if anything would you do differently with what
you know about it now? The list is awefully slow of late and seeing
your post made me curious as to your status since I haven't seen you mention
it in quite a while. Next Fall I will have my 25th college reunion in
St Paul, and I hope to fly my 9A up there to Blaine County...TBD of
course.
Thanks for any updates.
Doug Lomheim
RV-9A, FWF
OK City, OK
|