Recycled Detritus - Trial and Error
by Dave Watkins
Life is never straightforward. When I came to put the new engine in the chassis I found it was a few millimetres wider than the original aero engine. The gearbox width had fixed the original frame spacing and was not easy to alter. Drastic measures were called for. I clamped the chassis sides in the vice one at a time and bent them outwards to clear the engine at the front whilst at the back the width was the same as before. Believe it or not the bend is invisible unless one chooses to look underneath.
Having got the engine fitted it was time for the first running trials. For testing I used the fuel tank and engine silencer from the Nitro Hawk car. The fuel tank was tied on with rubber bands whilst the exhaust silencer projected outwards fouling the loading gauge. The starting ritual with a glo-plug engine seems as involved as starting a steam engine. It seems to take almost as long too. You need the right fuel, these car engines are designed to run on a mixture containing Nitro-Methane which smells awful. Screw in a glo-plug in good condition. Fill the tank with fuel. Put fresh batteries in the glo- starter and connect to the plug. Open the carburettor, block the air intake with a finger and turn the engine over to pull some fuel through. Now return the carburettor to the idle setting and spin the engine. With any luck it will fire and start to run after a few tries. The batteries can then be disconnected and the locomotive is ready for service.
On the first test run all went well for the first thirty seconds or so. The loco ran steadily if a little fast with clouds of oily smoke from the silencer. Then catastrophe. The projecting silencer would not fit through my tunnel. The locomotive stopped dead but the engine carried on trying to turn the wheels. The fly-cranks on the leading axle became dislodged. The rubber bands holding the fuel tank gave way and the tank outlet pipe snapped. In reaching into the tunnel to mount a rescue operation my fingers were neatly nipped between the moving connecting and coupling rods. Ouch! Carrying the chassis back down the garden I realised that in the short time the engine had been running several bolts had been loosened by the vibration of the engine, some actually left behind in a trail along the track. To add to the grief the rubber surface of the clutch plate had burnt away.
Now that I knew that it would run I could really begin to make progress. The loose bolt problem and the loose fly cranks were resolved with the aid of Loctite. A tin can was cut up and soldered together to make a silencer box which would fit inside the bonnet line well inside loading gauge. The exhaust is carried up through a length of brass tube which was once part of a radio aerial. Inside the silencer is a baffle plate which causes the exhaust to travel to the top of the box then down again to the bottom. A fuel tank soldered up from brass sheet replaced the now broken plastic tank from the car. I resisted the temptation to use more old tin cans to hold the fuel since glo fuel is corrosive. The clutch plate needed a new friction lining. My daughter Pat suggested wood. An odd scrap of 1/16” ply glued in place with super-glue worked just fine and has not worn away in several month’s use.
More running tests followed during which I was able to sort out the carburettor settings for fuel mixture and idle speed. I find that on a normal give and take track that I never need to touch the throttle setting which can be left on idle. “Detritus” is plenty fast enough at this setting.
Copyright Dave Watkins 1996.
If you want to contact me about leisure activities Send e-mail to: dave.watkins@blueyonder.co.uk