Ken, the 701 you are referring to is my wife's, that I purchased from the
flying school at Midland! My father-in-law's had done the same thing 2 weeks
prior to Bill (the flight instructor) putting it in the field. I had warned
Chris Heinz of this problem immediately after the "old mans" did it, when he
was turning around at the end of my strip. He, as most designers seem to do,
ignored me and then Bill ended up in the field at the end of -16- Midland 2
weeks later. The Zenairs use smaller diameter/thinner wall tube on the
pedals than the Rebel does, but it is something to consider and keep an eye
on as they are designed basically the same way. The other difference is the
"all flying" rudder on the 701 is a death trap in this situation as you
aren't strong enough with an arm to manhandle the cable to pull it back
straight. With the trailing rudder on the Rebel I <think> you could.
As for the balancer cable it can actually be done with just one large
diameter pulley at the firewall, by hooking the cables to the inner set of
pedals. This arrangement might add a bit of torsional load to the rudder
bars, but that was how XWI was before I put it back to the factory specs, in
this regard, and it seemed to have been working okay prior. Couldn't put it
back because the misc components in the Lyco installation got in the way of
where it had been run before, when she was Subaru powered.
Regards,
Wayne G. O'Shea
www.irishfield.on.ca
----- Original Message -----
From: "klehman" <
klehman@albedo.net>
To: <
murphy-rebel@dcsol.com>
Sent: Thursday, May 23, 2002 9:47 AM
Subject: Re: rudder pedals
I spoke to a fellow a couple of years ago that experienced something
very similar in a CH701. It has a very similar rudder bar arrangement
and in his case a weld on a rudder pedal broke. Even with full power he
was unable to maintain flight because of the resultant sideslip and he
ended up in a field.
Those of us who have extended the rudder bar an inch or so where the
rudder cables attach are increasing the load forces on those welds
perhaps 15%. The worst situation is of course when we are standing on
the brakes, not when in flight. Haven't heard of problems on the Rebel
but I still think checking the rudder bar for cracks and integrity on
the preflight has some merit.
I have considered implementing Wayne's thought of using two pulleys and
a balance cable instead of the springs. It looks like for my
installation I would need a small spring in the center of the balance
cable to make it work well (eliminate the slop). However I am seriously
trying to institute a "NO more time consuming mods" policy until after
Rebel 119 flies...
Ken
brian amendala wrote:
Hey everybody, I was taxiing the other day and my right rudder
turnbuckle
fell off the pedal. No big deal I always thought, until the spring from
the
left rudder pedal floored the left pedal, giving the airplane full left
rudder and no way to reverse the situation except try to pull the left
rudder up with my toe and pull the rudder back to neutral by leaning
over
the passanger seat and pulling the cable by hand. Not something I would
want to do while flying. I don't think the wind would blow the rudder
back
to neutral either considering the amount of friction in the system due
to
the floats. Should I get rid of the springs since they are only there
to
keep the pedals from falling forward? Are the springs we put in too
strong?
They are the ones from the plans. Thanks.
FrX-Mozilla-Status: 000953 2002
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Date: Thu, 23 May 2002 10:34:53 -0400
From: klehman <
klehman@albedo.net>
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To: Kenny Bauman <
kennybauman@yahoo.com>
Subject: Re: AirSIG: Megasquirt Address?
References: <
20020519164338.64823.qmail@web14403.mail.yahoo.com>
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Hi Ken
The GM KIGN module has been reported to give a small amount of advance
based on rpm only but I can't give you any good numbers. Might have been
in the order of 10 degrees at 2000 rpm but I don't really remember.
Doesn't matter very much for me as that is planned only for my backup
ignition for use with spark joiners at this point.
I am curious how you estimate 7% baro error with altitude changes? Seems
high to me off the top of my head. Not a show stopper for me though.
However I agree that resets with the engine operating might lead to
significant errors. My first inclination was to just change the software
so MS never does an ambient baro reading and see how things work. I
think the Soob ej22 turbo ecu used a solenoid valve to port ambient air
to the sole MAP sensor during startup but that seems like a step
backwards to me compared to full time sensing or no sensing.
At this point though MS is planned for my backup and I am still planning
the Soob ecu for the primary system. Thought I had all the Soob bits and
pieces but I am getting tired of hunting down missing parts so it is
possible I will scrap the Soob ecu before this is over. Currently I'm
missing the connector for the Soob ignitor. May have to hunt up a main
power relay as well. I would never recommend anyone try to use a Soob
ecu unless they have a complete running vehicle to start with! If I were
to scrap the soob ecu I think I'd go with SDS for the primary system.
Probably a lot less risk with SDS compared to MS but....
If you wanted a manual mixture (I don't except maybe for initial tuning)
you should be able to get it just by putting a variable resistance in
the temp sensor circuit. We know for sure that the ignition timing won't
be affected :). A pot that gets noisy might cause some difficulties
eventually. Probably not as bad as a noisy TPS pot that falsely triggers
acceleration enrichment though.
I only mentioned an alpha-N mode in case somebody else needed it. I
think the MAP sensor will be a better and more reliable solution for
most applications. And it is easier for me to plumb a second MAP than to
fit a second TPS sensor.
Incidently Ross at SDS seems comfortable with the idea of running his
system with no TPS or O2 sensor for aviation.
Ken
Kenny Bauman wrote:
Ken,
I remember a little bit about the GM KIGN. Seems that
it required a fixed advance. Is this right? Can you
refresh me a bit on it.
Your concept of not using a TPS input is fine. It has
in fact been done on the MegaSquirt list. The
gentleman found it worked just fine unless he "got on
it" too quick. Then he had a bit of lean stumble until
the MAP sensor caught up. But in XA that is not really
a concern. As far as a O2 sensor I think you are on
the right track as well. Bruce is working on adding in
WB O2 and I would like to see that.
I would use WB O2 to do my tuning then remove it
afterwards. In fact I still plan to use a WB wether it
is part of MS or not.
MS has two unused A/D pins. I plan to add in a
permanent full time BARO sensor as well as a manual
mixture POT. I would like to see full time BARO for a
couple of reasons right now. One, it is conceivable to
go from sea level to 10,000 ft in one flight. During
this you can see a fuel error of about 7 percent
without a updated baro reading. Without a O2 sensor or
manual mixture pot to correct it you will be running
the wrong fuel levels. I agree that most auto
applications do not read baro more than once and work
fine. But most car applications do not see much change
in altitude without a stop somewhere along the way for
fuel or a pit stop which of course resets the baro
reading. Second, some of the guys have been seeing
resets (from noise) on their MS units that happen so
fast the unit keeps on running without a engine miss.
(nice to know) Only problem with that is is the unit
takes a new baro reading during this unwanted
"startup" and of course is wrong because the engine
may be under vacuum or boost depending on if NA or
boosted.
Bruce is currently considering adding Alpha N
capablility which might be used as a backup mode if
the map sensor goes bad. As you mentioned he is
thinking of doing it for the big cam boys during idle.
But maybe we could hijaak it for backup purposes.
Only problem is I haven't done any coding in 20 odd
years. So I am more than a bit rusty. I'm guessing a
request on the MS list to change the code for full
time baro will result in a couple of posters. Should
be a very simple code mod. Manual mixture will
probably be slightly more difficult.
Ken Bauman
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