Rotorians,
Now that the airplane is painted,
weighed, prop ballenced and etc. I'm into tuning and getting
comfortable with the engine. Yesterday I noticed that as I ran the
engine up, #1 rotor EGT trailed #2 by 20 to 30 degrees and then at
about 20 inches of manifold, #1 started climbing rapidly! At max
static throttle 5828 rpm (prop speed of 2045) or so, #1 runs to 1640
degrees while #2 maxes at 1480 degrees. I played with the mixture
etc. No difference. I have checked the plugs and swaped them. No
difference. Stock RX-7 plugs. Pulled one and then the other secondary
inj. connector. It starts and runs and then drops off as RPM gets
high. Same on both #1 and 2. Swapped injectors. No difference.
Tryed using Mode 4, both to increase mixture and then to decrease. No
difference. Reset Mode 4 back to default. Swapped EGT probes. High
temps showed up on #2 on EM-2. Swapped back. Checked the archives.
Nothing. The EGT probes are installed through holes in the exhaust 5
inches from the engine outlet. So I am at a loss. Any thoughts on
what might be causing this? Engine basically running smooth and
strong. Months ago, I remember getting 6150 RPM, but couldn't get it
to run long enough to check out EGTs. Cooling problems. A couple of
other things that may or may not have anything to do with
this. Manifold display on EM-2 sometimes jumps around some. I have
tried porting to the front of the intake and to the rear. Now I have
it teed to both. Auto tune tries to work, but does not. (O2 sensor
installed at end of tangenial) I ran it almost 2.5 hours total
yesterday. 11.7 hours total. since last December. Quietest airplane
on the field. Lots of attention from other pilots.
Don Walker
RV-8 N113BR
Renesis 4 port. RD-1c
EC-2 EM-2
Tuned 17.5 inch intake.
Tuned 24 inch exhaust into tangetial
premuffler
catto 76/88. Field elevation 5000
ft. density 6200