Building a double acting wobbler

[Brian Rupnow]

Crewcab---It was more just a curiosity thing. You are probably aware that I am a design engineer www.rupnowdesign.com and many of the machines I design use pneumatic cylinders, and I always do force calculations based on an available supply of 60PSI. The majority of cylinders that I use range from 1" bore up to 4" bore, and for obvious reasons I have to calculate to know if they are going to exert enough "push" to do the job required of them. I was just wondering how much "push" could be developed by such a small diameter piston. If a person wanted to, you can then take the known "push" that is calculated, and using the length of the crankshaft throw as a lever arm, do torque and horsepower calculations. The reason I chose 20 PSI was simply that that is the pressure my first little single acting wobbler likes to run at. It had nothing to do with the Loctite. I REALLY hope that the loctite will do the job for holding the cylinder cap and the cap at the other end in place adequately. In a pinch, I can silver solder them, but I really don't want to.---And---Speaking of "age thing"---wish me a Happy Birthday"---I'll be 62 tomorrow. Ringo Star and I share a birthday, but I think Ringo is a couple of years older than I am.

 

[CrewCab]

I follow your train of thought now Brian, to be fair 1kg from a 3/8" piston is pretty fair imho .......... though it' s unlikely to be punching holes in aluminium plate : ........ I've found with my little wobbler that torque is almost non existent, then again that isn't really surprising when you consider the overall dynamics

Its a real learning curve to be fair ;D ............. but an enjoyable one.

CC

 

[joe d]

Brian

here in Montreal, most of the hobby stores have a small supply of brass and aluminum tubing and structural shapes from K&N Metal in assorted sizes... perhaps a little pricey for what you get, but convenient!

Joe

 

[Brian Rupnow]

Woweee!!! Lookit' the horns on that sucker!!! (My air inlet and exhaust) I'm still waiting for my Loctite 648, and I'm running out of things to make. I am going to have to step up to the polishing wheel in a big way, but I'm getting anxious to see this thing run.

 

[chuck foster]

brian you sound like you are having way too much fun

this little engine is looking good...........hope to see a video of it when it is running ;D 8)

chuck

 

[Brian Rupnow]

I went down to Brafasco's annual barbeque at noon today (Brafasco is short for Brampton Fastener Company) --(they are the industrial nut and bolt place around here) and managed to scoop a bottle of Loctite #638 from the rep. This is the same as #648 but it is thicker, and is billed as being for "loose fitting parts". I rushed home and slued everything together, and tomorrow I'll see if this thing runs or not!!!

 

[Brian Rupnow]

Well boys and girls--It runs like absolute magic!! It self starts too, as soon as I plug in the air hose. It is running on about 5 to 8 PSI in this horrible little video. if anyone cares to tell me how to get a better video with my 2 megapixel camera, or how to edit this one, I would be happy to listen. Far as the engine goes--I couldn't ask for a better runner. The fact that it is double acting, and the flywheel weighs a lot, seem to make a tremendous difference over the first little engine I made.

View attachment NEW ENGINE RUNNING001.MPG

 

[CrewCab]

Congratulations Brian ;D

............ that runs like "GUD UN" ....and IMHO the fact it runs on such a low air pressure is a compliment to your engineering skills

Nice one, unfortunately I can't get any volume........... which may well be my computer ...... nor can I offer any advice about Video on the ethernet, I leave that to the youngster's .............. Ralph, Twinsquirrel ............ shout up guys

I've enjoyed following the progress of your build from the start, well done, I'm well chuffed for you, very sweet runner 8)


Dave

 

[Brian Rupnow]

Trying out a video

View attachment Untitled.MSWMM

 

[shred]

See my other post-- that's not the video file, but the project file for Movie Maker that tells it what clips to use and where to do the cuts for the final video-- you need to publish or save the movie file also and upload that (it's not clear in Movie Maker-- the usual 'File->Save' only saves the project file)

 

[Brian Rupnow]

Okay--trying this video thing one more time.---Starting to feel like that saying about "Old dogs learning new tricks"---thanks Shred
http://s307.photobucket.com/albums/...ion=view&current=DOUBLEACTINGWOBBLERMOVIE.flv

 

[Mcgyver]

congrats, good on you.

 

[Dick L.]

Looks great Brian! Your on your way to having a collection now ;D Best of all you built it, there isn't any part you don't understand and can't explain or give advice on how to construct! A good feeling to be sure!
Dick

 

[chuck foster]

well Brian you better start designing and building a BIG display cabinet cause at the rate you are going ............ by Christmas you will have 40 or 50 engines to proudly display ;D

very nice engine and the video was well worth the wait

chuck

 

[bretk]

Brian,

Very nice engine and a good runner too! Ready to get going on Your Chuck's Horizontal Single Yet? I'm Sure You can get plenty of advice from us ;D

-Bret