Compressed Air V8 Cirrus

[cfellows]

Chuck

Are you making invisible gears now. If you are, then that explains why I can't see them. :hDe:

Cheers

Don

Don, are you suggesting the gears are a bit imposing??? They are pretty big but I didn't particularly want to make smaller gears and have to use an idler in between. I'm going drill holes or make spokes in the larger gear so it will be less bulky looking.

Chuck

 

[rhitee93]

Hi Chuck, I don't want to speak for Don, but I think there was a period yesterday evening that the gear photo wasn't showing in the posts. At least it didn't show up on my tablet last night. It may have just been me.

I'm loving the engine. Your design skills are impressive

 

[Maxine]

Nice application for the Arduino. Cool!

 

[mulac321]

Hi chuck very impressed with your work, can't wait to see it run. i've got a bit of a way to go before i could make 8 parts all the same . I've been working on an arduino Indexer for my rotary table, would be interested to here more abouts yours, was there a thread for it I missed?
Calum

 

[dsquire]

Don, are you suggesting the gears are a bit imposing??? They are pretty big but I didn't particularly want to make smaller gears and have to use an idler in between. I'm going drill holes or make spokes in the larger gear so it will be less bulky looking.

Chuck

Chuck

Honest. When I wrote that reply there was no hint of a gear in your post. As you know we are both moderators so we have editing privileges. I looked at your post and couldn't see anything that could link to a photo. It must be that gremlin at work again.

Whatever was the case I am glad to see it now and as usual it is more outstanding work from you. The whole project is imposing but in a good way. Thanks for continuing to share it with the HMEM members.

Cheers

Don

 

[cfellows]

Thanks to all for your support and kind words.

I thought for sure Don was poking fun at the fact that the two gears look particularly imposing in the photo I put up. Photobucket was doing some maintenance last night and none of the photos from there were displaying.

Chuck

 

[cfellows]

Hi chuck very impressed with your work, can't wait to see it run. i've got a bit of a way to go before i could make 8 parts all the same . I've been working on an arduino Indexer for my rotary table, would be interested to here more abouts yours, was there a thread for it I missed?
Calum

Thanks, Calum. Here's a link to the build thread for the dividing head:

http://www.homemodelenginemachinist.com/f39/electronic-dividing-head-using-arduino-17896/

I plan to rebuild the electronics using an Arduino Nano, and replacing the display/keypad combo with a new display and and infrared remote for issuing commands. I'll start another thread when I start work on that.

Chuck

 

[Aydelott]

I just made a similar crank but its only there pieces I have a few ideas on indicating it in true but I would like to know how you are going to do it ? Are you silver soldering it together ? Or press fit? it looks great!!!

 

[cfellows]

I just made a similar crank but its only there pieces I have a few ideas on indicating it in true but I would like to know how you are going to do it ? Are you silver soldering it together ? Or press fit? it looks great!!!

My crankshaft was made from one solid piece of 12L14 steel rod. Luckily, it turned out about as true as I could expect.

Chuck

 

[cfellows]

I am so tired of tapping. So far I count 106 holes drilled and tapped plus the 8 flare connections threaded on each end. But, I think the worst is done.

These are 8 pieces of brass turned from 7/16 rod. They are destined to become exhaust flanges that will hold the slave valve and spring inside the head.

I used my square 5C collet block to hold each flange while I milled a flat on opposite sides.

Here's 9 of them ready to drilled. I save the exhaust hole in the middle until the very end since it really weakens the piece.

And here's a few teaser pictures. Still got a few more things to complete before it's ready to run, but this gives you an idea of what it will look like.

Might have this thing running in a few days!

Chuck

 

[rhitee93]

Aesome!

 

[ozzie46]

Looks fantastic, Chuck. Can't wait to see and hear it run. Excellant build log.

Ron

 

[Don1966]

Wow! Chuck that is looking great, almost looks like a real Car engine.

Don

 

[SilverSanJuan]

Chuck, this engine is so cool! A really neat design. And, some really nice work by you. I'm looking forward to seeing it run.

Todd

 

[cfellows]

Thanks everyone, for the kind words.

I need 8 springs for the slave exhaust valve assemblies, well maybe 10 if you count the 1 or 2 that will almost certainly get dropped and disappear into another dimension or at least into the neighbors yard which at it's closest point is at least 50 feet from my workbench (they are springs, after all!).

So I found a smokin' deal on ebay for exactly the right sized springs...

I didn't count, but there are supposed to be 250 springs there. Guess I'll be building a few more engines...

Chuck

 

[cfellows]

Actually beginning to feel like an engine now. I installed the crankshaft, rods and pistons. I had to turn it over a few times with the drill, but that was probably just to remove bits of metal and dust. Turns over with my fingers now with little very little detectable slop anywhere. I'm sure there is slop, but I guess the misfits are in random and opposing directions making the overall assembly feel pretty snug.

Next I guess I'll decide on a flywheel. I could make another steel propeller, but that is a fair amount of work and I managed to get smacked by them quite a bit on the other two engines I build with propellers. Maybe a small, thick sectioned steel or brass flywheel, like those found on older marine engines? I'd gladly entertain any ideas...

Chuck

 

[kuhncw]

That is really looking great, Chuck. Very nice work.

Regards,

Chuck Kuhn

 

[Brian Rupnow]

Chuck---what a marvelous build!!! I've noticed it on the forum but didn't realize it was you building it. I have a sore back from too much machining today, so I'm taking some time to read through the various posts, and just discovered yours. Beautiful work as always.----Brian

 

[cfellows]

Thanks, Chuck. Thanks, Brian.

Here's the process of building the rotary valve tube.

The rotary valve tube actually starts out as a 3/16" length of drill rod. The first step is to press a small flange onto the back end.

I made the flange from 5/16" drill rod and drilled the center hole with a #2 drill bit which is about .002" smaller than the 3/16" diameter of the valve tube. I deliberately made the flange over-sized on both the diameter and length so I could turn it to finish dimensions after it was fixed on the valve tube (which is still a solid rod at this point). Here's how the valve tube will fit in the engine once finished.

Next I had to drill a 3.5" deep center hole in the rod. The only bit I had which was long enough was 1/8" so that's what I used. I had to back out of the hole, clear the chips, and add oil about every 1/8" to keep the drill on center and to keep the chips from piling up and seizing the bit.

Once the center hole was drilled, I inserted the valve tube into the crankcase from the back. Here's a picture of the valve tube fully inserted after I had drilled the center hole.

I then attached the larger timing gear to the front part of the valve tube where it extended out of the crankcase. Notice that the center hole does not go all the way through the valve tube. Here's what it looks like with the valve tube installed and the two timing gears attached to the valve tube and crankshaft, respectively. The crankshaft and the valve tube are now geared together and the valve tube will rotate at 1/2 the rate of the crankshaft giving the engine 4 stroke operation.

Here I've turned the crankshaft so that the first cylinder in the firing sequence is at top dead center (far right cylinder).

Next I attached a disk which has 4 lines scribed 90 degrees apart to the crankshaft. These lines are used to measure exactly 1/4 turn of the crankshaft.

Here I'm ready to start drilling the holes in the valve tube. I've already center drilled the holes in the flare fittings so it's just a matter of running the drill bit down until it hits the valve tube and drilling through to the center hole.

After drilling the first hole, I rotate the crankshaft 1/4 turn and proceed to the next cylinder in the firing sequence where I again drill a 1/16" hole through the side of the valve tube into the center hole using the cylinders flare fitting as a guide. This operation is repeated until holes have been drilled for all 8 cylinders. This results in 8 individual holes in the correct position for each cylinder. Note, however, that after I finish drilling all the holes, I have to retard the valve tube timing. As drilled, the holes are fully open when the piston would be at top dead center and in fact you want the piston to be half way through it's stroke before it's valve hole is fully open.

I hope this is a little clearer than mud. Let me know if you have any questions. I expect to have this engine running by the end of the day. Or perhaps I should, ready to run by the end of the day. Whether it actually runs remains to be seen!

Chuck

 

[rhitee93]

That is a clever way to position the valve holes. I am afraid I would have done it with an indexing head and a lot of calculating, and I would have messed it up a few times before I got it right! K-point from me.

Nicely done