Member postings for dean clarke 2

LOL yea sure no problem David just cruise on down to cambridge N.Z and we'll bolt it in. I was thinking that I might actually build an ME 109 to put it in, control line of course, about 76" span, what do you think? LOL. Hopefully i will have the crank finished tonight. I am in the middle of building a custom tool post for the lathe to eliminate the toolpost flex from the standard (not very ridged) toolpost. I knew i should have got the bigger lathe. oh well. will post the photo update later tonight all going well

dean

Ok so a quick update to let you know where I'm up to. I have made the fixture to turn the crank big end journels and found a slight problem, the fixture, with the crank in, was too big for the inside dia of my 3 jaw chuck. bugga!! now what to do. Luckily i have a larger 4 jaw self centering chuck so with a slight modification with a boring bar i can now machine the big ends, yay!! So i am now in the middle of making the tools to turn the journels. will post the photos if all goes well, maybee in the next few days depending on how much shed time my wife lets me have. LOL.

cheers

for now

dean

Edited By dean clarke 2 on 28/12/2013 03:06:20

Oh yea sorry i forgot to answer you muzzer, this is a glo engine running on methanol and nitro methane with a bit of good ole caster oil to stop the welding of internal parts.

dean

Hi guys and thanks for the comments and info etc. Hi jen, I accept what you are saying about 2 strokes with the port timing etc, and if you want to call it a scavenge pump then thats fine with me, each to his own, i will use the term supercharger as it will be forcing more mix into the engine than could otherwise be done. however without going into too much detail (secret squiral suff etc) LOL. the engine is arranged with porting and exhaust dimensions to allow some amount of positive charge in the combustion chamber, this is managed by using the rather large expansion pressure of combustion to act as a back door as it escapes out the exhaust system to allow positive transfer pressure to reach the combustion chamber. it is somewhat more involved than what i've just said but it does work. there are a few variables that need a bit more experimentation to finalise as it becomes a balancing act of appropriate pressures which will dictate drive speeds etc. Oh well i guess thats all for now will keep you all posted on the progress. The exhaust back pressure is also what helps stop excessive fuel consumption to a certain extent.

cheers for now

dean

p.s. before anyone asks i have done some experiments and yes the theory is sound and will run, actually it will run very well i think but like my nanna always used to say " the proof is in the pudding" so we shall see.

OK so another fine day in paradise and we saw the completion of stage two machining of the V12 crank. all B.E pins and main bearings have been roughed out to oversize by 1 mm ready for final machining to size.

Hopefully i will be able to finish machine and grind the crank this week, before christmas. Next will be the center main split bearings, backplate cover and blower drive.

cheers for now

dean

So heres the photos, LOL

dean

so the sequence goes something like this, make the blank then machine the flywheel dia. then maching the front bearing to 1mm oversize and mark out all the flywheel, bigend and center main bearings. next its off to the mill for indexing all the bigend location marks, mill out the bulk of material for the be to leave a small oversize square. this reduces the turning in the lathe for the b.e. journel. once all the b.e. and main journels have been roughed out i grind the b.ends to final size followed by the mains. Big end journels are turned with the crank mounted in a special fixture. finally cut all the chamferes on the flywheel faces and deburr and polish.

dean

Well started the crank tonight, here are a couple of photos of the first two stages of machining

1st is bar stock cut to length and faced and centered both ends

2nd shot shows the front main fournel roughed out to go into a collet chuck.

3rd photo shows machining the flywheel diameter.

cheers for now

dean

Hey guys , just thought i'd give you all an "assembled so far" bunch of photos of whats been done on this project up to date. i only have the blower rotor and vanes left to complete, then onto the crank.

cheers

dean

will keep posting progress if anyone's interested in seeing it?

dean

ok, so i had quite a bit of success over the weekend but also a somewhat frustrating disaster. got the supercharger case all but finished and both end caps machined up , made the offset turning fixture to machine the bearing holes for the blower rotor. this turned out to be not quite as straight forward as i thought as you will see in the latest photo updates.

having made the fixture i inadvertantly fitted the cover up 180 deg out and machined the wrong side, OOPS, bugger. oh well start that part again................

dean

Ok, so i have finished the front housing now, yay 1 more part down. this holds 2 21 x 12 x 5 ball races to carriy the front of the crankshaft. the rear end being held on a single ball race of the same dimensions. here are also the quad carb bodies i have roughed out along with the manifold.

Blower case is the next challenge, will post these photos as soon as i have done it.

cheers for now

dean

Ok, so i think it will help if i explain what i mean by super charged. the object of super/turbo charging any engine is to increase its ability to intake the air fuel mix over and above what its naturally capable of, right? So that being said you can super charge it by forcing more mix in. weather or not you achieve positive pressure in the combustion chamber is not the be all and end all (ideal but not the only end result) there are a number of efficiency losses in a model 2 stroke engine but by adding intake pressure you can remove these and gain a large power increase but still without reaching positive combustion chamber pressure. using the increased transfer pressure to help remove the leftover exhaust gases is also another plus to supercharging this engine, ( without the excessive fuel consumption), also the desgin of this v12 is with 2 con rods to 1 big end journal. this gives a 90 deg lag over tdc at number 1 to number 2 cyl. this equals a significant loss of crankcase suck effort, hence the addition of the super charger. So all this equals a super charged 2 stroke V12.

Dean

p.s. scavenging pumps are recovery pumps and strictly speaking not the correct label for intake pressure pumps. plus "super charged" sounds way more "heavy metal" don't you think? LOL i will keep you all updated with progress

here's the finished block only need to do the engine mounting holes. oh and the obvious finishing of the outside surfaces which will be done when all machine work is completed.

will keep you posted

dean

p.s. i hear what your saying about the open exhaust port but there is also a massive valve overlap in all high performance 4 stroke engines that run blowers too, so really it is not that different to a schnurle ported 2 stroke

hi again, thanks for the info. i believe that it is possible to supercharge 2 stroke engines. the object of the super charger is to create a crankcase pressure when it is unable to be used as a pump eg there is more than 1 piston in a common crankcase which therefor removes the ability of the crankcase to be a pump for the transfer. so add 1 blower and problem solved. there are many commercial engines that have been built to this design over the years. the berger 7 cylinder 2 stroke radial is just 1 example that springs to mind.

will update photos tonight as the crankcase is now finished

dean

here is the first stage of the block.

hi guys ,just thought i'd let you all know of my latest attempt at this model engine building lark. Am just in the process of making a supercharged v 12 2 stroke and will try and post photos as i complete bits etc.

dean

The 10G anf 12G are the threads the dies cut., the g means gauge, so they are a 10 gauge and a 12 gauge die.

dean

hi guys, just wondering if anyone has come across multi cylinder glo engines not running when the plugs are turned off? any ideas on a cause? my v8 just doesn't want to keep running without power to the plugs. runs perfectly when they are connected.

dean

Edited By dean clarke 2 on 27/01/2013 06:32:35

sounds like you need to change the big end journals and use needle roller bearings of the right diameter, silver solder them to the webs and problem solved.

dean

here's a few more of my engines, hope you enjoy. Dean

Edited By David Clark 1 on 16/11/2012 20:32:32

thanks for the good comments, all the engines are my own design, the twin on here was my very first engine build, i cheated a little with this engine as i have used proprietry cylinder liners, 1 with a piston but the other i had to fit another original piston to it, lapped it in but otherwise i made all other parts except bolts and glo plugs. the engine runs not to bad for a first timer but i think my eyeometer was out a little on the intake port timing but never mind it still runs well. the v4 was my third engine and the first v4 i made. again propietry liners were used but this time i lapped the liners and made new piston etc for them. the crank is a 1 piece affair with the conrods split on the big end. crank is 4140 ht steel and rods are 2024 t6 alloy. be bolts are ht 00/80 cap bolts cast iron pistons with all other alloy parts from 6061 t651. after seeing ramonds mlling out the cases from solid i gave that a go with the 2nd inline twin. will upload the rest of my engines today. the v8 is the first engine i have done where i have made the liners as well.

thanks

dean

p.s. all engines are made useing manual machines and scribbled scetches with a few dimensions no plans as such

Edited By dean clarke 2 on 01/11/2012 19:36:45

Edited By dean clarke 2 on 01/11/2012 19:37:43

Edited By dean clarke 2 on 01/11/2012 19:40:16