Rotary Valve Engines and seals? (design)

Modern RC airplanes work like that, the carb sits on the crankshaft, the crankshaft is hollowed out with a port machined into it, the fuel and air runs through the crank and into the housing, then once the piston is down to a certain position, the fuel and air is ****ed in, really cool engines and they rev up to 30k... well that is at least what my grandpa told me back when i was little

but the first rotary valve in a internal combustion engine was some time around 1895-1907, cant remember exactly but i read the patent on it.

 

All 2 stroke engines work off that same principle... The piston moving down compresses the charge in the crankcase, which then blows through the transfer ports up into the cylinder. That's why 2 stroke cranks have such big cheeks next to the rod. They try to take up as much crankcase area as possible. The Gnome aircraft engine wasn't a 2 stroke though...just bizarre.

 

You might find some useful plasma spraying/coating info inquiring here. I worked developing machines there when they were called Hobart-TAFA. They developed spray ceramic coatings. Along with more pedestrian wire fed thermal coatings
http://www.thermalspraydirectory.com/Praxair-Surface-Technologies-cp352352.htm

 

A**** the Gnome rotary's interesting features is that it used a "total loss" oil system in which the oil was mixed with the gas and went out with the exhaust. Castor oil was the lubricant of choice since gas did not break it down. An unfortunate consequence was that much of it was blown back in the face in the pilot, who often wore a scarf to wipe his goggles and the windshield. Pilots also experienced first hand the laxative qualities of castor oil. The Gnome also had no throttle and ran wide open all the time. To reduce speed on approaches, the pilot used an ignition cutout switch to intermittently kill the engine while slipping the aircraft. All in all, it was an ingenious design well-suited to aeronautical use due to its low weight, but required a lot of maintenance.

 

There are good reasons that popet valves have suvived as the choice for four stroke piston engines. The internal combustion engine relies on how much heat can be produced for a given amount of combustibule fuel. Rotary valve engines connot match the efficincy or endurance of popet valves. There are three considerations here, cost, endurance, & efficiency.

 

Ill agree with you somewhat on efficiency, from my calculations, a normal rotary valve doesn't get much advantage over a poppet when comparing its valve charts vs the weight to get more valve area, but my heads are not a normal rotary valve . efficiency isn't just a bang, there are a lot of factors that dictate a engines efficiency. As far as heat, you want your combustion chamber to be as cool as possible so your intake charge doesn't heat up and prematurely detonate, rotary valves, or at least mine, will run way cooler than a poppet valve, so ill be able to run a high compression ratio than a poppet valve equivalent running the same fuel, which means a bigger bang, which means more power, + my 180° power stroke.

The main disadvantage of poppet, aside from rev limit, is that the exhaust valve is constantly being bombarded by explosions and heat, resulting in an extreme hot spot in the engine, I've fixed that.

For cost, i think we'll be alright , so far with the trend of our superchargers and our cost vs compe***ors sales, we could destroy the market if we wanted to.

For endurance, meh i can do all the calculations i want but we will only see once i have one working. My designed has revolved around controlling heat and seals.

 

interesting thread.
It made me research a bit about rotary engines and valves.
Something I had never though about prior.

 

Makes me think about what would I build if I had the resources?

High strength, big inch, high flow oem looking flathead ?

Hemi heads for corvairs ?

High strength big inch alloy Olds big block ?

Friend owns this rotary design...http://www.circomdc.com/

Thanks for the thought producing thread and good luck with all of it!

 

Can't remember if it was this thread or another but someone showed me this engine and i just found a new video of a company developing the exact same design today so i figured i would share it.

<iframe width="560" height="315" src="http://www.youtube.com/embed/njb5DqsC9L0" frameborder="0" allowfullscreen></iframe>

 

Dzuari - how is your rotary valve engine project coming? It’s been a few years since you posted in this thread so I imagine you have some Dyno data by now?