I was wondering...

[ccdewitt]

The holes are square because the end is shaped to release the bar in the situation where the engine kicks over. This is particularly true in gas engines but it works in big steam as well. If there is a residual slug of steam in the steam chest and the valve opens as you bar the engine over it would be good if the bar self released rather than striking you or the boat.

The end of the bar is finished to an approximate chisel shape but much blunter than a chisel and kind of rounded. Round bars don't lend themselves to this application.

[TahoeSteam]

Thank you Chris for your insight from your wealth of historical knowledge

[double simple]

Bart, have you ever seen a bar starter on a Rumley Oil Pull. A ramp in to the face of the flywheel with a square shoulder. The starting bar had a pivot point on the frame. Slide the bar against the square notch and pull her through, when it fired the ramp kicked the bar out and you set the bar in the holder and away you went.

Bob

[Lopez Mike]

I have a friend with a giant antique Cletrac bulldozer. It has a huge four cylinder gasoline engine and is started with a crowbar. The holes in the flywheel are round and not that deep and are relieved on one side thus that you can only turn the flywheel one way. Thus if it kicks back, you are not killed.

At least not right away. The whole process is beyond barbaric!

[barts]

I've started both Rumley Oil Pulls and (small) Cletracs, but that was 30+ years ago , and I've forgotten some of the details, surprisingly enough.
Thanks for the ideas!

I have just enough space between the arms on the frame to increase the size of the flywheel to 14"; if I cover the OD w/ a suitable slip resistant
tape, I could literally kick the engine over w/o difficulty as the larger flywheel would come up over the engine base by a bit. This would be used for starting. A series of holes would still be useful if the engine was 'stuck' , but those would not be used when steam is present to prevent problems.
I'll need to check w/ the boat designer to make sure the box keel can be wide enough for the flywheel.

A flywheel 14" in diameter and 3" thick weighs about 128 lbs. This will be interesting to clean up in my 15" lathe. The drive for the prop is taken off
the end of the flywheel as in gas engine boat practice; I'm securing the flywheel to the crankshaft w/ a heavy duty keyless bushing (fennerdrives.com). This avoids current a slot for a 1/2" key in the crankshaft, and more problematic, cutting a 3 x 1/2" internal key in the flywheel. This bushing takes both the engine torque and the prop thrust.

- Bart

[Mike Rometer]

Why is a key slot in the flywheel a problem? I cut internal keyways in the lathe. It's a bit labourious but it works perfectly.

Set your material in the chuck/faceplate and lock the headstock. Then with a specially cut tool, set sideways on the centreline, in the tool holder, wind the saddle back and forth increasing the cut on the tool a few thou at a time, 'til the correct depth is reached. If the slot is too wide to do in one hit, raise the tool half the difference and cut the top section first then lower the tool to the full width and repeat. You can't remove massive amounts of metal each stroke, but you soon get the hang of how much you can remove.

[Lopez Mike]

I like the modern tapered compression sleeve solution a lot better. I've spent too much time getting flywheels off of shafts after years of use to ever get myself into that situation again. I'll be changing my little 3 x 4 over to that setup the next time I have the engine out.

Bart, I dunno about having any sort of gripping surface on the flywheel. I kick my flywheel a lot, of course, and am often very happy that my rubber sole and that flywheel don't grip each other that well. Keep the oil and grease off of it and you will be fine.

[DetroiTug]

Just after one year, I tried to pull the keyed shaft coupler off of my engine to add the flywheel and it was a chore. And it just slid on there with slight interference originally (light tap). Had to be heated and use a puller. I now use anti-seize on all steam engine stuff (steam car stuff too). So far, so good.

-Ron

[Oilking]

Bart,
Putting the flywheel on the prop end "as in gas engine boat practice". FYI: The engines built to be marine engines such as the Chrysler Ace, Crown & Royal, the Atlas Skipper, and the Palmer's and so on, had flywheels on the front end. This was desirable on the Columbia river bow pickers with somewhat steep shaft angles it allowed the clutch to nestle down between the engine timbers and flatten out the shaft some. The starters were mounted high on the side of the block, not slung low in the bilge, a feature you'd appreciate if you've ever opened the cabin door to find the floor boards floating. My opinion is that the stern mounted flywheel didn't become common practice until after the engine builders discontinued making true marine engines and all they were selling were automotive engines adapted for the marine market.

Your project continues to inspire. I must get out in the shop when things warm up a little. With no heat in the shop, last week I did a little job for a friend, had to crank the mill by hand and then run it for 15" at slowest speed to warm up the gear box.

Best wishes to all!

Dave

[barts]

Yup - went back and looked at a lot of images, and the big flywheels were stuck on the front, probably to avoid interference w/ the reversing gear and to allow the engine to idle at low rpm. In any case, since I don't have a gear box, the drive comes off the rear mounted flywheel. With the box keep, the engine and prop shaft are horizontal in the boat.

Interesting. I did some calculations, and the 14" flywheel inertia pales in comparison to the inertia of the 28" prop. The reason for the flywheel is so that the engine can be turned over readily, and so I can run the engine before it's in the boat .

Season's Greetings to all -

=- Bart