[modeleng] Lackham Petrol Head Update

Last night it was the turn of Stumpy and Topsy to be tried at Lackham.

Stumpy had a new forward/reverse controller and had been tried (on the
bench) at home.  Topsy was brand new and is her first time out.

Stumpy (375cc Kubota 4 stroke engine, Eaton drive unit, "drive by wire")

I knew that there was going to be trouble when we were unloading him.  There
was a pool of petrol on the trailer floor.  An inspection of Stumpy showed
that it was coming out of the air intake.

I removed the foam filter and wrung it out!  Replaced it and tried to start
Stumpy.  Eventually he caught, but would only tick over very slowly and
would not pick up speed.

Then more petrol was seen coming out of the air cleaner.  It was obviously
flooded (I know, it's obvious now and to all of you who are shouting at your
computer "CHECK THE FLOAT"). So I did!  Nothing obvious, but one clean float
bowl later and he started.  However switching from "Normal" to "Run" in
Stumpy (some of my wiring) and he would stop.  It was traced back to the
wiring in the Driving Position in the Driving Control Trailer (DCT).
Without the circuits (or tools!) I couldn't do much, so we arranged it that
we could drive Stumpy, we just couldn't kill the engine remotely.

The new direction control worked well.  It is going to take some getting
used to, but I am sure it will come with practice.  The main difference is
that the previous forward/reverse lever had 4 positions either side of
Neutral and the lever "mimicked" the servo (and thus the gearbox) position.
The new one (based on a screw thread) has one position either side of centre
(not even neutral!) "Up" drives the thread one way and engages more and more
"Forward" and "Down" drives the thread the other way and engages more and
more "Reverse".  Mid positions stops the drive.  "Full" forward or "Full"
reverse just drives the screw to the maximum extent at which point it stops.

Post testing note - when I got back and looked at my circuits I found out
what a prat I had been!  If I had put the switch into "normal" and then
started Stumpy from the DCT, everything should have been OK.  I'll try that
tonight.  The reason for the "local" start button is so that I can turn the
engine over when adjacent to it, there are time when I need to see what is
going on and the DCT is 7' away (and I can't reach that far!)

Topsy (24v 2.5kW electric motor, 2 x 12v large batteries, 75cc 4 stroke BSA
engine driving an alternator as recharge for the batteries)

Wow!! Frightening or what?  This loco has a serious amount of installed
grunt (approximately 2.5kW/3.3HP 24v electric motor).  My calculations were
for a top speed of 10mph (I reckon that we are exceeding that and that is
what is frightening!)  Apart from that (and with the exception of the petrol
engine - more later) All worked well.  The controller from 4QD was very nice
and can control down to a very slow speed.  Topsy moves freely and nothing
catches.  It also copes with the 40' radius curves and I was a little
nervous about that as it is a 3 axle engine (2 driven, one guidance)

We initially had the petrol engine running and that seemed to cope with the
load being taken by the electric motor, however later on it would run and
then stop (even when "off load").  More petrol problems I think.  Something
else to play with tonight.

I forgot my camera last night, so I'll take it with me tonight and when I
get time I'll update the website(s)

All in all a good evening

Cheers

Peter



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