Supercharged V12 2 stroke

[steamer]

Awesome!!!!

Hey Vixen.......you see what I see?   8-)

Dave

[777engman]

Ok hopfully here are some photos of the V12 going back together'
cheers Dean

[777engman]

Here's the blower drive assembly.
Dean

[777engman]

So after an unacceptably long time lapse, I have also made a start on the new carbs, photos below show the progress to date. I have managed to get the anodizing plant completed and running as the previous photos show. I have also been carried away with colouring in some more of my engines so thought i'd share the results with you guys as well. photos below.
cheers
Dean

[Admiral_dk]

Whoa - I was impressed with the "Raw" version of the V12, but now it's a real stunner 

Very beautiful blower-drive case 

I like your other engines too and would especially like to know how you did the single carb system on the flat four - is through the crankshaft or ...?

Best wishes

Per

[777engman]

Thanks, was a bit of a challenge, had to anodize it twice, all parts on the v12 are machined from solid there are no castings used at all. The flat four has the intake through the crankshaft center main bearing, rotary valve. drilled through from the rear of the shaft with an aluminium valve fixed in the intake to control intake from front to rear. the engine is alternate firing ie both front pistons go out to TDC, while both the rear piston go in to BDC so there is still crankcase pumping. Same with the V8 only its repeated twice to feed all 8 cylinders. the V8 does at this time 10,000 rpm.
Cheers
Dean

[Admiral_dk]

So I'm assuming (dangerous, I know, to Ass-U-Me  ) that you mean a plain bush bearing with a hole on one side for the inlet + a bored through centre crank with two perpendicular holes through it and with a asymmetric plug in the middle - or am I completely off the mark here 

[777engman]

Na your pretty much right on the button. although the valve is like you say a plug drilled in from each end leaving a portion in the center. after its fitted to the crank you machine through from the outside from each intake port and hey presto you got alternate firing intakes. will upload some photos in the nest day or so.
cheers
Dean

[777engman]

Hey there admiral, I have just gone back over the comments and noticed your comments/questions regarding rpm etc. The main reasons for the lack of throttle response between idle and w.o.t. on the first run is a combination of slippage on the blower drive and a lack of breathing through the blower and intake. This part of the problem was rectified by increasing the blower intake holes by 50% by volume and the 6 injection ports by 25% by volume. That's why I am now making significantly larger carbs to allow for much better breathing. Obviously the slippage problem has been fixed by the toothed belt drive but the drive speed has also been increased from 2.5 to 3.5 times crank speed. Can't wait to see the results LOL
will let you know how I get on
Cheers
Dean

[Admiral_dk]

Thank you for your reply Dean.

I guess that's why it called tuning - you keep on adjusting the parts until you reach the desired result and this is normally accomplised when all parts + timings and port sizes mach each other 


I made that mistake when I tried to get my old Viking diesel running - I shouldn't had adjusted the inlet timing to "match" the transfer and exhaust timing since I didn't think about the port shapes it did not match afterwards ....   

[petertha]

Fantastic 777engman! I'm really interested in the details of your phenolic blade supercharger. Somehow I missed the pics until I re-read you post & saw the Picasso link this time. Do the phenolic vanes basically float outward against centrifugal force? Are the blade ends rounded or receive some special profile treatment? Is typical methanol/oil 2-S premix fuel sufficient to lubricate everything? How is the housing temp behaving now that you have had some run time?  I'd love a sketch showing basic section dimensions or link that discusses design at this scale?

[777engman]

Hi petertha, here's the link to my build thread for the V12 on model-engineer. there is a bit more info in that thread.

http://www.model-engineer.co.uk/forums/postings.asp?th=90605

              basically the blades are made parallel and the outer edge is rounded to run against the housing. the two ends and inside edge are flat and square to the blade. there is approx 0.001" end float of the rotor and case ends and the rotor runs approx 0.001" away from the case side. when making this blower i designed it to have the same displacement as the engine. there are no springs etc to aid holding the blades outward so I just rely on the centrifugal force, but the down side is that the blades often get stuck in the rotor when the engine has been sitting, due to the oil gumming them in. but if I added springs then the running tension on the blades would increase dramatically and then become a problem. this blower is machined from 6061 solid hex section bar stock, however the next V12 will have a cast main crankcase with the blower case and fin blocks all cast as one piece. I will then press in a stainless sleeve for the blower vanes to run against. this will remove the wear problem with running in a cast casing. (hopefully, LOL). As far as housing temp goes when running there is very little if any perceivable heat on the outside of the blower case, thanks to the methanol!, lol
hope this helps explain it a bit better.
Cheers
Dean

[777engman]

Here's the next step in the addition of bigger and better breathing carbs for the V12..
photo's show progress to date










If you right click on the photo icon and select open image in new tab it will take you to the online album on google.


Cheers
Dean

[777engman]

well that didn't work, lets try that again shell we.......

[777engman]

Here's a photo to show the difference in the throat diameter between the old and new carbs, hopefully this will rectify the breathing restriction issues the engine was struggling with.
cheers for now
dean