john, perhaps my email is not working but if you recieve this please
respo\nd even if it is only to say you can not help me , i need the updated
motor glider manual that you posted for me earlier and i failed to copy. as
my original manual was comple\tely diferent thank you chrisa160 mg
----- Original Message -----
From: "Europa Aircraft" <europa@gate.net>
Subject: Re: Europa-List: Hobbs switch
>
> Hi All,
>
> Lockwood recomends a hobbs to record engine time for oil changes, other
regular maintenance & diags. Both Mitchell, and UMA make electronic
tachometers with a time readout. Mitchell also makes a 2 1/4" mechanical
recording tach for the Rotax 912 / 914.
>
> Hope this helps.
>
> John Hurst
> Europa Aircraft
> Lakeland, FL
>
> -----Original Message-----
> From: Jim Brown <acrojim@cfl.rr.com>
> To: europa-list@matronics.com
> Subject: Re: Europa-List: Hobbs switch
>
>
> On N398JB we connected the Hobbs meter to the Master switch, which
eliminated any taping into the oil system for pressure. If we need to have
the master on for what ever reason without the engine running we simply
pull the circuit breaker.
>
> Jim Brown
>
> n3eu@comcast.net wrote:
>
> >
> > > This has probably been discussed a million times before. Typically
when I
> > > am involved in a certain section of the build I become focused and
tend not
> > > to assimilate some of the other stuff coming over the web. I need to
> > > install a switch for the Hobbs meter. The first thought is to put a T
> > > where the oil pressure transducer is and plug in the switch upstream
of the
> > > transducer. Are there any other pressure ports on the 914 that I'm
not
> > > aware of? What have others done to ensure accurate recording of engine
> > > hours with the Hobbs?
> > >
> > > Thanks,
> > >
> > > Steve A143
> > > Mesa, AZ
> >
> > Why do you really need to know accurate Hobbs time? As an amateur-built
aircraft in the U.S., you're not bound in the slightest degree by any run
time of any component anywhere. Admittedly, were you to sell the aircraft,
airframe/engine time will be of interest to a buyer and thus how determined,
but big deal.
> >
> > So, my "Hobbs" time is from that which a Taskem digital RPM display
actually records in nonvolatile memory. Good 'enuf!
> >
> > The only place to tap into oil pressure is at the pressure transducer on
all Rotax 91X, or the feed line to the 914 turbocharger. But the grizzled
old aircraft mechanic in me says you do that you introduce a point of
failure in a critical airworthiness system. It's not like there's a Service
Bulletin on my other airplane specifically on this, which on failure causes
oil to be spilled inside the aircraft cabin, until there ain't nuthin' in
the sump!
> >
> > Thus preferable would be to simply read voltage at the Rotax transducer,
and glomp a transistor to fire a stock Hobbs meter. It's a simple circuit,
but if a builder can't do that, I think it best to at least shop for
something that will record elapsed hours when fed a voltage, like when
master is on -- even a stock Hobbs does that. It won't be exact engine
hours, but so what.
> >
> > Regards,
> > Fred F.
> >
>
>
|