Large Model Association Forum

As all my current projects have been more or less completed its time for this winters project.

I'm starting by fabricating the engine using the spares I've lying around in the shed. As I've a number of Zenoah 62 lying idol, a couple of the engine couplers I had fabricared some time ago and a couple of props that are two big for anything else I think I'll have a bash at making a triple.

My zenoah inline twin has done a couple of hours now and is running great so it'll just be a longer version of this.

I'm fortunate to be in the same club as Dave Brown and instantly snapped up his Mick Reeves reduction drive inverter which he showed me yesterday, this will place the cylinders in the air stream better.

As the photo shows the engines are bolted together so now I'll fabricate the cage that goes around it.

Thanks to everyone who commented on the bear yesterday at Gaydon.

Looking forward to this, as I´m eventually going for a tripple myself one day.
And even though I normally prefer the sound of a gas engine running at very low rpm, 4500-5000 in the case of my King 140, I can also appriciate the aggressive sound of a two-stroke tripple inline. Nothing comes close to the shear anger of these things. :-)

Here is a clip I found on YT.
http://www.youtube.com/watch?v=cnCi194t5jU

And another one flying.
http://www.youtube.com/watch?v=YF4Mofe6ltY

The Master of shedoligy strikes again. Great start Karl. I picked up the bearings for the crank mod to help out with your MR drive set up so will try to get it done next week all being well. Pic of the prototype plate to replace the spacers & help support the second bearing, similar to the mod for my drive unit

Dave

As the engines are all lined up by the couplers I've then made the frame from 25mm by 5mm aluminium angle. I've spent the week drilling and tapping pieces of angle so it's all bolted together, as per my twin I'll have the frame welded.
I've then bolted the reduction drive to the front of the engine using Dave Brown's inverter. There's a saying that if it looks right it will be right and this is the case here.
with the inverter fitted the cylinders are in the air stream as opposed to the original Mick Reeves reduction which covers the cylinder with the reduction unit.

How have you "timed" the firing strokes, every 120deg?

Cheers,
Dave.

I was thinking the same on the angles Karl. If you need the couplings re drilling for 120 degrees I will do them for you. Its looking great shedoligy rules.

Dave

Dave

Well your reply regarding seperating the engines certainly has made me think. Unfortunately I find thinking a painful and tedious activity that makes me pull funny faces and leaves me unable to do simple tasks like walking or talking.

It would appear that I may have made a slight mistake ( I'll blame my 5 year old son he can clearly be seen making the mistake). I bolted the engines together so that one piston was at top dead centre, one bottom dead centre and by measuring the stroke I was able to put one mid cylinder.
As I've been trying to avoid turning the engine over to avoid the ingestion of swarf into the cylinders I havnt seen when the pistons were hitting tdc.
If you think for a while you will fathom out where I went wrong.

My future plan is to measure the circumference of the flywheel, mark a piece of tape this length devided by three equal distance marks then apply this to each flywheel using the position of the magnets on the flywheel as a constant and the coil as the constant point on each engine. This should give me the 120' separation. Or I might just bolt them together so they give a big bang altogether.

Hi Karl, its going to be interesting to hear the engine when you start her up. Just a thought, have you got your carb bends yet as I am about to order some for two other engines I am putting together. Also I knocked up some insulators today to suit them.

Dave