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No, I have the 2.85 gearbox. I have
the MT electric prop, so I fly WOT and use the prop to govern the engine
speed.
I have changed the plugs with no effect.
The mixture is fine when this is happening. Fuel pressure also. I had
an incident once on take off like you describe where the plane was backfiring
like crazy just after I lifted off. I had the mixture too rich. I dialed
it back and everything smoothed out. This is different. It doesn’t
really backfire. It is a thump and it jerks the engine and plane. You
can hear and feel it. It seems to be a single thump and it has varying
degrees of violence. Some are just a little miss and some are so bad it
shakes everything. These are less frequent, but they are bad enough that I
don’t think they are good for the PSRU, prop, or engine mount.
That is why I have been bugging Tracy about the change
for the EC-2. I have my fingers crossed that this will fix it.
:>)
Bill B
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net] On
Behalf Of bktrub@aol.com
Sent: Tuesday, January 08, 2013
7:14 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Aeroquip
hose changed to hiccup
You must have the 2.17/1 gearbox. I had
some problems at that RPM due to the CAS's being wired with the wrong polarity.
I could take off just fine, but when the RPM climbed up around that area, I
would get horrendous backfires and stumbles, and my shorts would become soiled.
This would happen at about 250 feet on takeoff. I don't think that that is what
your problem might be, Since this just started and is getting worse, maybe a
check of your spark plugs? I wouldn't think it would be fuel starvation, but perhaps
you could check your fuel pressure when this is happening. I can only think of
it being one of two things- ignition, or fuel. You can rule out compression for
obvious reasons.
Good luck, hope you find it soon.
Brian
Trubee
-----Original
Message-----
From: Bill Bradburry <bbradburry@bellsouth.net>
To: Rotary motors in aircraft
<flyrotary@lancaironline.net>
Sent: Tue, Jan 8, 2013 1:51 pm
Subject: [FlyRotary] Re: Aeroquip hose changed to hiccup
Yes, it is happening at WOT, 2000 ft, 5800
rpm. Staging was long past.
Are you sure this sin's happening when
the injectors stage? I had it happen once while taking someone for a ride,
didn't figure out what it was until after I landed.
Yes, bench testing on the EC2 version is
complete. Don't know what vintage your EC2 is but the early ones did not
have O2 sensor inputs and can't take advantage of the closed loop modes.
That is unrelated to the possible cause of the hiccup though.
I went thru and cleaned up all my grounds
and it seems to have fixed everything with the exception of the hiccup.
Tracy, have you finished the bench testing on the EC-2 upgrade
yet? I would really like to try and see if that will fix this
problem. My wife really doesn’t like that hiccup!
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net]
On Behalf Of Bill Bradburry
Sent: Saturday, December 08, 2012
3:41 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Aeroquip
hose
I currently have a separate ground from
each of the batteries to a Nuckolls “forest of tabs” ground
point. Everything inside the cockpit grounds here. Also the fuel
pumps and injectors ground here. The coils ground on the center
iron. There are separate grounds from each battery to the PSRU plate on
each side of the starter. I have considered bringing two separate grounds
from the center iron to the batteries just in case there is resistance getting
from the center iron to the PSRU plate.
I am also taking all my grounds apart to
check for corrosion or anything that seems that it might not be properly
bonded.
I am doing this for two reasons.
One, I am still getting that occasional “hiccup” that is violent
enough to shake the plane when it happens. It is bad enough that I am
concerned that it might be bad for the pin in the PSRU. I am also
wondering if it could be the PSRU that has sheared the pin and is
slipping? Someone on here had that happen and I would really appreciate a
description of what that sounded and felt like and also how I could make
certain that is not the problem. No, I don’t want to dismantle the
PSRU to check it unless that seems to be the only way to check it.
Also, Tracy, how are you progressing on getting the
upgrade for the EC-2 that might fix this hiccup if that is what it is? I
think you had it done for the EC-3 and were working on the EC-2
implementation??
The second reason for going thru the grounds
is that I am having an intermittent problem with my GTX327 transponder, MFD150
moving map, and TruTrak autopilot shutting down. This seems to happen
more often when I key the mike on my GNS430W radio, but keying the mike is not
required. It sometimes happens just out of the blue. Also most of
the time, only the transponder shuts off. Only sometimes does the moving
map and autopilot join in the fun.
Everybody tells me that it sounds like a
ground issue, hence I am going thru the ground system.
I welcome all opinions and input!
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net]
On Behalf Of Tracy
Sent: Saturday, December 08, 2012
10:56 AM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Aeroquip
hose
Tying the engine parts together should not
be necessary but you still need a separate ground from battery to airframe
ground (if metal) and your avionics ground point. Also separate
feeds from +12 battery to starter/alternator and avionics. You can Use
the starter/alternator feed for coils, injectors & fuel pumps to keep noise
down on the avionics bus.
Tracy
Several months ago, after a discussion
with Tracy, I
ran grounding straps from each battery to the PSRU plate on both sides of the
starter mount. I had previously had the grounding strap running between
the center iron and the “forest of tabs” grounding block on the
firewall. Tracy
suggested I move it so the starter amps would not get into the grounding block.
Now I have the igniters grounded on the
center iron and I am considering running a ground strap from the center iron to
the batteries or trying to tie each section of the engine
“sandwich” together by running a wire between them. This
would to be certain that the ground is good on the igniters.
From: Rotary motors in aircraft
[mailto:flyrotary@lancaironline.net]
On Behalf Of Andrew Martin
Sent: Friday, December 07, 2012
8:29 PM
To: Rotary
motors in aircraft
Subject: [FlyRotary] Re: Aeroquip
hose
Bill
As Mark says + make sure you have a ground cable/strap connected battery direct
to your starter. Do not expect starter to ground through your engine without
problems.
I remember Tracy
posting on this issue years ago just a bit hard to find in the archives now.
Andrew
You may want to check your engine ground.
Starter current may be causing this.
I am working on cleaning up my ground
system and I noticed that I have
several, 3 or 4, places on my SS braided fuel hose that appears to be burnt
like it had an electrical spark exit from it. I have not found anything
in
the vicinity of these places that look like where the spark? would have
jumped??
Has anyone seen something like this and what should I do about it? Do I
have a ground problem in the engine compartment or is this maybe static?
The hoses are covered by SS and are connected on one end to a filter that
has a ground strap on it and on the other end to the fuel rail which is
grounded to the engine.
Bill B
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