messing around with flywheels

Marleysky wrote:Way to go! Very nice rrrrrrun!  I gotta make one of those throttles. Too Cool! Thanks !


PS: only video 1 opens and plays, #2 & #3 say they are unavailable.
SNL is on, see ya tomorrow.

I don't know why vids 2 & 3 won't play.. I experienced the same.. then the issue seemed to subside? Let me know if there's still trouble viewing them.

Thanks VERY MUCH for watching!!!

Just an FYI.. the 2nd and 3rd vids are viewable now.

Ken Cook wrote:         Roddie, that was pretty cool. Now, do you have boat plans? I have the shaft, the universal and the prop.I would need to fabricate the stuffing box for the hull. I'm not certain if Dumas offered that. I would love to put my parts into use.

Thanks Ken, It was a fun little indoor project for a cold Winter's day.

CEF member halfAnut (Brad) is the man to ask about anything related to running a Cox engine in a model boat. He's given me lots of helpful tips.

Regarding Dumas running-hardware; they used to produce complete kits designed for Cox engines, for running in their 1/2A size boats.

I have the Dumas hardware kit #2306 which is designed for running a Cox .049 engine in their Atlas Van Lines hydroplane. I also have the AVL hydroplane kit.

shown below is Dumas kit #2306



not shown (in the sm. envelope) are prop-drive pins and a 5-40 fully-threaded stub-shaft which connects the engines' crankshaft to the kits' U-joint.

The AVL kit is long-since out of production.. and quite collectable.



I got mine through Tower Hobbies back in the early 1990's. I started building it.. but stopped when I had trouble understanding the instructions.

I did build the Dumas "Short Stuff" (aka DV-10 or Deep Vee 10) but powered it with a Graupner electric motor/hardware kit.






I don't know if those drawings will help.. but I'm sure that there's a myriad of model boat plans available for download.. or maybe "Brad" has some that he'd be willing to share. My AVL kit-box/plan is buried.. so I don't know (and can't remember) if it's a full-size plan. I doubt it though.

A few years ago I bought some small replacement model-boat props and drive-shaft set produced by "Aquacraft" for their little "Reef Racer" model. I figured that they might be adaptable for Cox engine power.

The Aquacraft props and hardware are metric.. but they utilize a "drive-dog" type prop-coupling.. which is superior to what Dumas offers/offered. The Aquacraft props are also suitable for a "surface-drive" application.. which is likely what you'd want to run in a high-performance hull.

Here's another configuration and test-vid for running an ultra-lightweight (.15oz./4gr. my lightest thus far) flywheel on the same engine.





Just to reiterate; the glow-fuel being used is a blend of Sig "Champion" brand 25 and 35, which is decades-old. Keep that in mind.. if you ever decide to throw-away your old/aged glow-fuel. It may still have some "kick" left in it...  

If you watch this video, please be patient... because it was a "cold-start" condition. It took me a few minutes to realize that the engine wasn't getting any fuel.. and the use of my muffler prevents priming the cylinder through an exhaust-port.

I found it interesting; how "little" fuel was required to support combustion this time. The mixture-needle was only open 1/2 to 3/4 of a turn. Any "richer" was too much "drag" on combustion with such a light-load. (at least that's my synopsis.. )

This one's for Ron Cribbs.. The same engine.. with the last tests' .15 oz./4gr. flywheel.. except an extended high-speed run to possibly obtain an audio-tach reading.

For those who don't know; Ron CD'd the 2017 CEF "Tach-Race".. which not only proves that he's a great guy.. but also a bona-fide "speed-junkie" (just kidding..)

Hey Ron, It bummed me out that your tether-car's drive-wheel came-apart during testing.. and took the TD .020 with it..

Please accept my apologies if you already know the following information. The Cox .020 engines' crankshafts are threaded for a 3-48 UNC size machine-screw. This screw happens to fit nicely "snug" into the "I.D." of 1/8" standard-wall alloy tubing. Any wheel having a "hub" to accept a 1/8" (.125") axle could easily be fitted to your engine.

I have a supply of 1" length 3-48 black-oxide cap-screws.. and also some standard-wall 1/8" alloy tubing, in either aluminum, brass or copper. I also have 3-48 nylon-insert style lock-nuts.. and various assorted-diameter model-wheels having a 1/8" hub..

Let me know if you can use any of these items to make repairs to your tether-car. Can you use that engine-mount.. or is it for a Tee Dee .010?

getback wrote:That last run was cranking out some rpm's wish you could have got a tach reading , maybe Brad or Andras will chim in and ck. it . Good testing Roddie !!

Hey bro! Yea.. that little mill was screaming... Not sure if you caught-it in my dialogue.. but the mixture-needle ended-up being "leaned-out" to within one-turn open, to achieve combustion on every stroke.

These no-load/flywheel-tests weren't intended to prove much.. but let's examine a few variables..

The test-engine was configured using a crankcase and cylinder assembly that I had "on-hand". The crankshaft was not removed for de-varnishing. I concentrated more on the induction-side; making sure that fuel was reaching the venturi.

The .049 Bees' crankcase was fitted with an original copper/star reed-valve. Some modelers claim that the copper reed will "float" at higher-rpm's. .............  

I'd put "this test-engine" in any model..