ptulmer

My Feedback: (5)

This idea has been bouncing around my head for awhile now. Lotsa room in there, so it's been bouncing alot. You lathe guys might have to slap me around to get this thing out.
I've got a little machining experience and a pretty decent understanding of how things work. I want to design an engine that could be made COMPLETELY on a lathe with a drill press nearby. (I've still got to get a lathe!)
Here goes-
Radial mount screws into back so no tabs to worry about.
Crankcase thick enough that the cylinder can screw down into it.
Cylinder similar to a cox and compatible with galbreath head.
Front intake or reedie?

Anybody interested in helping with the design or making one?

epilot

Check out these diesels. Both nice simple designs. No reason why you can't use them with glow instead:

[link=http://archive.dstc.edu.au/BDU/staff/ron/midge/]Midge[/link]
[link=http://www.geocities.com/joby19672002/NGEZ-1/NGEZ-1.html]NGEZ[/link]

I have plans for both and am currently building the Midge.

Michael

combatpigg

My Feedback: (3)

PATRICK, how about an ABC TD with a wrist pin?

SERCEFLYER

I've got to agree with EPILOT-- the Midge and the NGEZ would make ideal conversions to glow. Go to Ron Chernich's site-- there's a bunch of prospects there, including a glow version of the EZE. Next week, I'll be heading back to Buffalo for some time in my dad's workshop. I can't wait to pull out the Taig lathe and start working on some other parts for the ML Midge. It'll be a miracle, though, if my first attempts produce a running little diesel.

SF

slowstick

build a lathe with a part # 4486-2vga at harborfreight .com and your drill press also there are some homemade lathe plans on some of the metal working sites

ptulmer

My Feedback: (5)

Most of these engines were timed to turn big props at slow rpm's. CP has got the idea. The #1 reason is that I'd like to do something new! So simple and straightforward that a beginner could make a great engine.
The wrist pin throws a curve. Simple method to make without a mill? I'm not a fan of the cox method, so an alternative would be nice!

And time it to turn some rpm's like a norvel or better!

combatpigg

My Feedback: (3)

Make the wrist pin out of music wire, and polish the ends round. Then just peen the wrist pin in place like NORVEL does it. I use the smallest hex driver shaft that I have, and lay it down edge on right where I want to deform the piston, and give it a whack. I don't know where you get high silicone content aluminum, but that is what keeps the pistons' expansion under control. A sharp gunsmith might have the tooling to do a cylinder and could handle the hard chroming.

ptulmer

My Feedback: (5)

What's so difficult about doing the cylinder? It could be done with something like the leadloy steel, but then you'd need a steel piston? Whatever materials are use should be readily available. www.onlinemetals.com is an easy source. Materials are whats really stumping me. I don't know much about that part.

If you use aluminum for the cylinder and piston, what would need to be done to the surfaces that rub?

I do like the Norvel system for the wrist pin running through the piston skirt. Easy to do. A drill press is all you'd need besides the lathe.

combatpigg

My Feedback: (3)

Well, you would be going to alot of trouble to go with leadloy, and the reward wouldn't be as good as if you used AAC or ABC, especially since many of us scored a bunch of those $6 leadloy engines]. There may be some pit falls with a screw in liner made from brass or aluminum that I don't know about. Those guys who have the small engine websites would probably be glad to give you better guidance than "machinist wannabee 1st class" COMBATPIGG!

Dan Vincent

Congratulations, you just invented the 1947 K&B Infant .020.

John Brodbeck told me he built the entire Infant on a Screw Machine.

ptulmer

My Feedback: (5)

I think a screw machine is more complex than a lathe that can make threads. That is a neat little job though.

I'll do a little looking into the ABC type of cylinder. A little steering in the right direction is what's needed. I still think this is a worthy project. Something similar to the russian engines with the bolt in crankshaft bearing thingy and disc rotor might be the ultimate answer. The entire cylinder and crankcase(?) would be made on the lathe and so could the bearing supports...and the disc rotor. Leaving a liner and piston/rod/crank. All could be made on the lathe with a drill press close by. The ports in the liner...can you mount a milling bit in the drill and move the part using some kind of vise? Hmmm.... sounds like I might be inventing a mini mill too.
Is there a vise that can be moved like a milling machine for a drill press?

ptulmer

My Feedback: (5)

Zagnut posted a name in another thread. I looked it up. Check this out- www.emachineshop.com

Tim Wiltse-RCU

Patrick,

There's my 2cents(keep the change). A mill is really needed I think. But if you are willing to use parts that are already being made you would be ahead of the game. I myself would very much like to make something using the Norvel cylinder and piston. It has a wrist pin and great fit. But it gets hard because I don't know how to make the ports into the case as most cases are cast and not billet aluminum. Though now that I am thinking about it I could just remove the venturi/carb on one and grind the boss off and JB weld it closed and make a screw in rear rotor backplate. Anyways...at the very least you would also need a milling attachment for the lathe and then you will be kicking yourself for not having a real "mill". When I started messing with machine tools I figured a lathe would be so cool and I was thinking of all the stuff I would be able to do. Once I bought it I quickly realized how bad I need a mill too. I don't think you can build a rod without one.
Trying to make your drillpress pull "milling" duty is sort of unsafe. Most drillpress's have a chuck with a taper fit. Trying to mill on them will shake the taper free and things or yourself could get hurt. A mill has a draw bar that bolts the tooling into it. Most drills have to much runout anyways. Like I said just my 2cents.

LAter,
Tim

ajcoholic

My Feedback: (10)

actually a dedicated mill is not needed, a milling attachment for the lathe is more than adequate for building a small engine. I built many an engine from scratch long before I got my first vertical miller. Now that I have two mills I dont use the vertical slide on the lathe but it sure did the trick when that was all I could afford.

AJC

BMatthews

A buddy of mine that has done a LOT of engine work over the years put me onto a neat trick for the cylinder and piston. Cylinder liners or full cylinders with fins are cut from Leadalloy as mentioned above and then the pistons are machined from chunks of old cam shafts from American V8's. The cams are made of a nice fine grained cast iron and the leaded steel and cast iron have a very high resistance to galling of any sort. He's done a lot of vintage stunt engines for folks and even with a lean run that makes them lock up they show no signs of scoring or galling and start right up and run fine once cooled down.

Wrist pins are easy. Not music wire as it's not actually that round. But steel dowel pins are ground to tight tolerances and are very hard. And they are dirt cheap as well. Here again my buddy uses them not only for crank pins on a couple of occasions but also did a bunch of Fox Combat engine cranks that used pressed dowel pins for the crank pins. They were good enough to do well at the Bladder Grabber until the Nelsons and stuff came along.

I'm wondering if there's enough of us that would like to try an engine of this sort if it would be worth doing an RCU project engine. I'm thinking an 074 or .10 size that uses basic porting and maybe a slightly longer stroke to allow turning a larger prop at sport flying rpms. Glow and muffler with a throttle would be part of it. I'd say it should be capable of being made entirely on a lathe as not everyone has mills. But that does not mean that some hand tooling could not be used to shape parts. I'd like to see the slightly larger displacement so we don't have to wring it out and require fancy metals to withstand the stresses. It would also mean the parts would be slightly larger and easier to work with.

Might be kind of fun. I'd be up for a project of this sort. Any others?

For myself I think either a piston port intake or reed intake would simplify such a first time project.

ptulmer

My Feedback: (5)

HEY BRUCE! I was wondering if you'd pipe up. I'm hoping to get a lathe in a week or two. Saved up some $$$ to follow up on your advice to go as big as I can afford. Sounds like we're on the same page. I'd like to get something drawn up so I'll have a project when the lathe gets here. A .10 is fine with me. Displacement isn't as much a factor as ease of building. (it should probably be 1/2a though)
By piston port... what's that? Like a disc rotor?
My thoughts on the bore/stroke and timing/porting was that I'd like it to run as good as the OS LA series of engines. Most of the designs out there won't go above 8-9k.[:'(]

ZAGNUT

My Feedback: (1)

i say let's make screamer, not just another pretty side-port show piece that won't even register a reading on the average tach...and can i add a hacksaw and a drill press to the needed tools??

did some more doodling on something with a 12mm bore and stroke, comes out to .082 ci....and tried to keep it simple.

1. piston and/or backplate need no cutouts for clearance at BDC so it can be built as a rear exhaust, disk valve with no probs

2. crank will have a 10mm main bearing so it can be done as front intake too

3. rear bearing will be seated half way in the case and half way in the front housing. should make it easier to keep everything accurate

4. from the top of the exhaust port down the sleeve will have 3.5mm wall thickness so that all the transfer passages can be cut directly into the outside of the sleeve. NO dicking around inside the case and NO mismatched ports. make up a few cylinders and optimize the design without ever touching the case....also leaves enough meat to bore it out to 13mm for .10 c.i. displacement


the rest of the parts should be easy, will draw them soon



dave

BMatthews

Zagnut, I like what I see so far but let's loose the beam mounts in favour of a backplate flange to stay within the "lathe and drill press only" field of play. Also I see the exhaust port is a more complex rectangle shape. Here again I'd suggest we need to stick to the basics for now.

I like the .082 size. Large enough to work well and be easier to work with the parts yet small enough to be made even on a table top Sherline or Taig.

Ptulmer, the piston port is where the carb sticks out the side of the cylinder like a Mills or those other small diesels linked above.

Screamers usually means Schnuerlle (sp?) porting and either requires some fancy milling or some careful layout and Dremel grinding. It may be easier to work in a modified TeeDee style opposed porting that can be done on the drill press prior to the final cylinder boring process.

It would be a great project to learn not only about engines but making various jigs and tooling to allow the machining operations to be carried out. And we need to bow to the idea that the design will be at least partly driven by the skills to machine the parts and to produce the fixtures and tooling to perform the operations. It would be nice to make a copy of some high zoot thing like the Shuriken but it's not practical.

BMatthews

And as each of us gets our alloy parts done we can box 'em up to send to Tim for anodizing....

ZAGNUT

My Feedback: (1)

the exhaust is just four holes on the drill press and some dremel work don't have to be too neat. and can be made much larger if the header bolt holes are deleted...

and yes, the sleeve here is thick enough to do any kind of port/transfers that come to mind. the cox style ports would be real easy without any of the limitations of the cylinder base threads

loosing the beams would make this super simple, find a chunk of alum and drill it full of holes...


dave

old git

Most British motorcycle and cars used High Silicon content Aluminium. 10-12% Si AL, the same as the Al brazing wire. I cast many small bits using Oxy Acet flame and Al brazing flux. If making a casting WEAR GOGGLES, KEEP MOLD DRY!!!

My uncle had the worst case of "adult acne" you ever saw using a damp mold. The water in the mold turns to steam in an instant, bursting the mold and spreading hot metal over the vicinity.
He was wearing goggles and his eyes survived.

For 1/2a pistons maybe all you need is to saw a lump off to fit in the lathe.

ajcoholic

My Feedback: (10)

My opinion... hoping to make an engine that is going to be a "screamer", expecially for those who have perhaps not made an engine yet is very unrealistic. Yes, I am sorry to burst some bubbles (and you all should know me, I am not out to discourage anyone, yet I feel you better be realistic as well) but trying to, as a first project, produce an engine to rival the norvel or even cox will be a lot harder than many may think. Been there done that!

I agree with Bruce- stay will a simple single bypass/exhaust design, either piston ported or simple reed valve. If you want to go with a front rotary intoake thats fine too, the case is a little harder but...

I have an idea: I will offer to cast up an aluminum crankcase for the project. I would love to take part in this, I have been involved in a model engine building group before and it is fun if everyone works towards the same goal. I also have some design experience and have built dozens of engines from scratch so I do know a little of what I speak of...

My fear is that if someone wants to go into this thinking it is "easy" to get a great running little engine and then when things are not quiate as expected, there is dissapointment. Heck, it took me 8 or 10 pistons before I got my first engine to even fire properly. Learning the skills and art of building engines while trying to make "the" perfect engine is not practical, again in my opinion.

I suggest we start with something mildly ported, designed perhaps more for easy construction rather than the highest performance and lightest weight. Something a little more forgiving if one gets the timing off a little, or the clearences less than ideal... you know what I mean?

I can add my casting services to the group if thats the way you all want to go. WHo exactly is interested? And what about the actual design? Who will make the final descisions? I suggest looking at some older engines for ideas and inspiration.

Its sounds like a fun project!

AJC

ProBroJoe

AJC - thanks for speaking up! I was going to post something along those lines, but I don't think I could have put it so eloquently.

That's a very generous offer BTW, and if this project gains any momentum, I think folks would be wise to take you up on it. (I hope that you would at least charge something for the crankcases to cover your time, effort and materials.)

In the spirit of keeping it simple, I would have to recommend a design that contains no screwcutting, as many folks won't have that ability on the smaller lathes. I also agree with you and Bruce that a single transfer, single exhaust, piston ported (or reed induction) design would be best for a first attempt. (Although I still can't comfortably suggest that a novice machinist build any I.C. engine as a first project.)

Anyway, it sounds like it could be a fun project if people remain open-minded, aren't quick to criticize, and are willing to make a few comprimises. Oh, for what it's worth, I'd be willing to offer CAD / design assistance.

-Joe

[link=http://www.geocities.com/joby19672002/NGEZ-1/NGEZ-1.html]http://www.geocities.com/joby19672002/NGEZ-1/NGEZ-1.html[/link]

gws1

My Feedback: (13)

I'd like to build one.

ZAGNUT

My Feedback: (1)

i also have a lot of experience tinkering with these things and know how HARD it really is, especially getting a good fit between the piston and cylinder. but things like disk valves, rods, heads and even cranks are very doable if you have the patience and take your time. unless you're using the backplate from a cox then reed induction isn't any easier than a disk or shaft induction, the only really simple option is the piston port IMO

anyways please excuse my drawings and posts if they aren't in line here, it's just that this is the first time i've ever played with any type of CAD program and i simply can't help myself

so here's the front housing, bearings are 8x16 and 10x19. housing weighs 10 grams and the case is 19 but could easily loose some weight with a good filing job[>:]



dave