Steve; Get your Fluke meter out & check voltage drops on ground circiuts, sounds like the starter/cranking is using the majority of voltage available, could be due to bad ground for starter (could even be high draw from starter itself, have seen this on cars diog. for poor starting) when I tried to crank our 13B RV6A for the first time only got a click, painted everything so well starter had bad grnd. Cleaned the paint off all contact areas, cranked great. Hope this helps. David R. Cook, Lansing MI, RV6A Rotary N655HC (paperwork, paperwork, paperwork)
----- Original Message -----
From: "Steve Brooks" <cozy4pilot@gmail.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Saturday, November 21, 2009 10:49:48 AM GMT -05:00 US/Canada Eastern
Subject: [FlyRotary] Need a sanity check
I have been working on an issue for three weeks now, with very
intermittent spark when cranking the engine. Needless to say, it won't
start either.
I have a spark plug out of each rotor, and have them clamped to a good
ground, so that I can see a spark on the front and rear rotor.
If i rotate the CAS by hand, or turn the prop by hand, I get good spark.
When cranking with the starter, I get an initial spark, and then an
occasional spark on the front or rear rotor. Interesting, when I let
off the starter, I get a couple of good sparks as it coasts to a stop.
Both controllers do the same thing BTW.
I had emailed Tracy, as at one time I thought that the EC-2 had an
issue. Tracy said that he had seen this symptom a couple of times
before, and it is caused by noise from the starter interfering with the
CAS signal. He suggested that I install a 1K resistor across each of
the crank angle sensors. I installed the resistors, but it did not cure
the problem.
This morning, determined to get to the bottom of this, I removed the
battery cable running to the starter, and using a spare battery, and a
jumper cable for the ground, I cranked the starter with this battery,
which was isolated from the airplanes electrical system. It had good
spark on both rotors .... yeah !!!
So then, I decided to reroute the starter cable on the other side of the
engine, which keeps it away from the other wiring. I hooked it back up
to the aircraft battery, crossed my fingers and cranked the started.
Same problem. I thought that perhaps the noise was getting into the
EC-2, so I put the spare battery in the back seat (pusher aircraft), and
using some jumper clips, I hooked the EC-2 through a fuse to the
isolated battery. Same problem.
I had extended the CAS wiring when I replaced the engine, so I decided
to reroute the shielded CAS wiring, so that I could eliminate the
unshielded wires, which were about 12" long. Same problem.
I am struggling with what to try next. This problem started before I
swapped the engine, as it was very hard to get started, though for three
years prior to that, I had no issues, and it started easily.
Has anyone else seen this type of problem, or have any suggestions ?
Steve Brooks
Cozy MKIV 13BT
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