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Just read through my thread here and see maybe I haven't explained exactly why this Common crankcase 60 degree Vee Twin configuration does not work. In theory it seems like it will - and as someone said recently on another thread, with the closeness of the 2nd piston following the lead one...

I know this thread is about the build of a wonderful engine and maybe one shouldn't "but in" - but thought I'd add here that I have built two .. 60 degree Vee twin 2 strokes and have proved that although it looks like it will work in theory as a big single, fact is that it does not. The lead...

When I made the 60 degree Vee Twin based on the Midge, I used the best piston / cylinder combos in it and the worst one of the 3 - stayed in my Midge. A couple of days ago, I decided to "fix" the Midge and get it running nicely. It had bags of compression but spat the fuel/air mixture back out...

How did you make the finger grip for the needle valve assembly? Simple - paid David Owen about $14 for an MP Jet needle valve assy ... David's details can be found at http://oea.modelenginenews.org/pricelist_2013-05.pdf I must admit I've never made a NVA - I cheat and always buy one from...

Hi Jack, Must have been looking at the engine upside down - you are correct it is at BDC that the top of the piston uncovers the inlet from the venturi and the residual exhaust gases mess up the incoming air. Apologies .. I did make a longer conrod and it changed the behaviour to a sweet...

Johnny, not much different really, in a single you get your fingers out of the way just a few degrees after top dead centre if you do it right - this is the same - except it fires 180 degrees earlier for the next impulse. Well, I just ran it again this morning, trying to get a better feel for...

Hi Jack, tdc is correct - you want to see what the underneath of the piston is doing in relation to the inlet hole. In my case it was literally a hair's width uncovering the port, you could JUST make it out as the piston dwelled there, BUT, what it was doing was allowing the crankcase pressure...

3 weeks and 2 days later .... https://www.youtube.com/watch?v=IsEZ9w8dW7I It runs quite nicely, but suspect there is a lot more power available with some tweaking. Video here with a 11 x 4 Turnigy wood prop. One thing it has proven so far is that the bolt together interlink crankshaft...

Darren Simpson, a fellow HMEM member has been keeping up with me very kindly doing the CAD drawings. This rendering is fantastic, what an incredible tool CAD is. Darren says that it can even work out the weight of things when you put in what the various materials used are. Compare this to the...

Starting to look like a motor now ! Just honing bores, making pistons, conrods, contras and backplate to go. Oh and a couple of tommy bars to go back on the Vee Twin! The plenum chamber worked out well, a nice snug fit between the uprights, so I don't think any sealant will be necessary. A bit...

Hi Neils The interconnect housing is about 15mm long and is a tight fit in the crankshaft tunnel, likewise the interconnect shaft is a very close it between the ball bearings - so although there would be a leakage of sorts - it for all intents and purposes negligible in my opinion. Certainly no...

Nose piece, front crankshaft, propeller drive and spinner nut done. The nose piece has a ball bearing on the internal end, but a bronze bush on the outer end. I am not sure why but I prefer this method of supporting the shaft, and it gives a better seal as well. All the fits are very close...

Next step was to insert the pins .. I used drill rod 5mm diameter and pressed it into the rear disc by drilling the hole to about 4.9mm then machining down the drill rod to a thou over that isze the thickness of the disc, then a nice tight fit into the disc. Next problem was the hole for the...

A bit more progress .... Interconnect shaft housing made and installed with countersunk screws from beneath. Was going to hide them under the plenum chamber but realised that the rotating masses will be pushing against the screws and against the thou or so clearance, better to position them at...

Have now completed the cylinders and the crucial interconnect shaft which has a bolt on rear crankdisc. Using 2mm caphead bolts the crankdisc can be removed and this allows the shaft to be supported by ball-bearings internally. Drilling 4 x 12 mm holes then tapping was done very carefully, a...

Here is the completed crankcase - documented on a .pdf Will also photograph and describe other facets of the build as we go along. Hopefully if the engine is successful then might serve to inspire some budding machinists to build one. Ed

In a way this is a continuation of a previous thread called the 60 degree Vee Twin 1.6cc and the remnants of that thread at time of starting this one can be found at http://www.homemodelenginemachinist.com/f31/60-degree-vee-twin-1-6cc-22760/index6.html where mention is made of this new design...

Gail, thanks for that ... Neils, Don't worry I won't be pulling the V-HOT apart to rob its bits ! Yes the power increase with a cylinder blanked off is something I want to investigate down the track, it is an impressive increase and I don't think it is down to the ball bearing on the conrod...

Gail, Would you believe sheet No.8 was being printed here as you were typing your post ! Great minds and all that. I spent this morning reading through your build of the engine, and what a wonderful design it is. Having made the Midge and then a Vee out of the Midge - then making the next...

Thanks Neils ... hope I haven't disturbed your sleep too much. About to start on another project, this time an inline twin and again based on the Owen Mate. It seems to me that the crucial factor in this type of motor is the link between the front and rear crankpins. I have looked at various...