V12 Model Aircraft Engine

[Adaware]

Progress?

[Crevice Reamer]

Nice project. That's a great airplane! I was once weathered in at a mid Pennsylvania airport and wandered into a T Hanger where a guy was working on his personal P-51. The wing Gun lockers were huge and he carried cargo/luggage in them. Said he could fly it from there to Miami in just 2 hours.

I'm worried about your aluminum bearings without sump lubrication. Two cycle engines circulate that fuel/lube mixture through the crancase. That won't be happening with a 4 cycle engine. Steel/aluminum contact is dicey at best with lots of oil around it. That won't hold up long running dry. I think you are going to need some pressurized oil to those bearing surfaces.

CR.

[dynosor]

I'm worried about your aluminum bearings without sump lubrication. Two cycle engines circulate that fuel/lube mixture through the crancase. That won't be happening with a 4 cycle engine. Steel/aluminum contact is dicey at best with lots of oil around it. That won't hold up long running dry. I think you are going to need some pressurized oil to those bearing surfaces.

CR.

I agree with the need for direct oiling of the main bearings; hence http://www.cnczone.com/forums/showpost.php?p=536418&postcount=10

It is a lot to read, but here is the gist of it: "Lubrication will be by means of 2-stroke model fuel and oil ways to the crankshaft - "belt and braces" approach".

[dynosor]

Progress?

I played around with generating cam profiles over Christmas. Not ready for parts release yet, but here is a single lobe camshaft I modeled to try and figure out the lift, acceleration and jerk. I have not been able to make the follower (not shown) follow the lobe in SW yet...

Edit: I know the valve doesn't have a groove or thread to retain it yet, but I wanted to see what it looks like with 1/8" stem. There may be room to take mass out of the valve face instead of leaving it flat.

[Adaware]

Have you figured out where you can place the cooling/oil channels yet?
I've drawn så many head designs i have lost count but then i began to look at motorcycle engines and then it all came togeher, my idea is to have a two piece head to incorporate cooling jackets over the combustion chamber and exhaust ports.

Where will your cam bearings be placed, in line with the head bolts or maybe inline with the spark plug?

[dynosor]

Have you figured out where you can place the cooling/oil channels yet?
I've drawn så many head designs i have lost count but then i began to look at motorcycle engines and then it all came togeher, my idea is to have a two piece head to incorporate cooling jackets over the combustion chamber and exhaust ports.

Where will your cam bearings be placed, in line with the head bolts or maybe inline with the spark plug?

I have had many ideas, but am yet to finish the model. I like your two piece head idea - casting a cylinder head with intertwined cooling channels and curved ports is easy compared to machining one...

The cam will probably operate by means of rockers with roller followers - yes, the model suggests bucket tappets, but achieving low friction will be easier with the rocker pivot taking the "wiping" loads from the cam and using a roller follower.

[cforcht]

Dyno,
you have my curiosity running again. where are you on this project? is it done yet?

[dynosor]

Dyno,
you have my curiosity running again. where are you on this project? is it done yet?

I shelved the V12 to work on a less complicated boxer 6.

I have only gotten as far as making the crankshaft for the latter - I am presently stuck at setting up a tool post grinder to finish the journals.

I cheated by buying the pistons, liners and cylinder heads with valves etc. for a 0.7 cubic inch Magnum commercial engine (1" bore and 0.75" stroke). Unfortunately the importer couldn't supply a quantity of 6 for all the parts, so I am waiting for the rest on back order.

Yes, I know it is a shame to lose momentum on a project; especially compared to your extremely impressive rate of producing parts.

By the way, the V12 design was the vehicle I used to teach myself Solid Works. Before that I had never used any kind of CAD software, unless you count a soft pencil and drawing board. While I did conceptualize designs, I always had other engineers to do the detailed design work for me.

[cforcht]

I had considered buying pistons and such at one point long ago when I kicked around the idea of making a V8 but there were other obstacles in the design I didn't have an answer for at the time. So I never began the project. obstacles like cam,ignition things of that nature. and shelving a project for back ordered parts is naughty. too many times Ive done similar and then never finished the project. heres some pic sof the 6 year gun safe I built. I didn't finish it until I got laid off and needed something to do. so I dusted off the 6 years of dirt and got after it.






if something is back ordered, then work on some other part until the parts arrive. that's what I did with this engine build. the cam gear was back ordered.

[cforcht]

FYI the big motor was for counter weight. with the door open it wants to fall over to the left. once installed its screwed to the wall and the floor. the door required using a cherry picker to put it on its so heavy. there is a lifting eye in the top of the door. I think I went a little over board on building the door. I built it because 95% of the gun safes on the market are crap. I decided since I have an FFL I should be in compliance with the BATF rules of gun storage. just in case they popped in for a visit someday.