4 stroke chainsaw

[Stere]

That RCV stuff is interesting but seems nothing  new happening with then for a few yrs nor sure why development stopped?

 

https://pdfs.semanticscholar.org/dc8d/d88169fbdb9399a7dbe340faf1a779a77d2c.pdf

 

Looks good must be some downside though i assume?

 

Dolmar had a  wankel rotary chainsaw.

[Stere]

Another one:

 

Freedom Motors

WWW.FREEDOM-MOTORS.COM

---

Freedom Motors is now producing one of the most flexible, efficient, durable and powerful engines in history:...

 

[Macpherson]

2 hours ago, Stere said:

That RCV stuff is interesting but seems nothing  new happening with then for a few yrs nor sure why development stopped?

 

https://pdfs.semanticscholar.org/dc8d/d88169fbdb9399a7dbe340faf1a779a77d2c.pdf

 

Looks good must be some downside though i assume?

 

Dolmar had a  wankel rotary chainsaw.

 

Aye, the downside is that it's the total fecking answer to efficient combustion of fuel in IC engines which along with other buried tech like Hydrogen fuel for example would totally contradict the nasty crap narrative that we're expected to swallow these days... I mean, a simple engine that has twice the efficiency of what's considered normal that more completely combusts the fuel leaving far less waste products and is all in much better all round ... Why wouldn't you embrace the idea / concept?

 

Answer.. the military has and that's where it's gone.

 

Interestingly enough, on the same subject an English engineer named Frank Aspen is worth a google👍

[openspaceman]

4 hours ago, Macpherson said:

Interestingly enough, on the same subject an English engineer named Frank Aspen is worth a google👍

I remember his design, a similar rotating valve in the head but it was conical.

 

At the end of 1940s the piston engine had just about peaked with things like the rotary valved sabre and even the diesel nomad but jets just eclipsed them. Much of the reason the techniques (other than multiple valves per cylinder and double overhead cams which are ubiquitous now) didn't transfer to commercial engines was the reliability and in the case of rotary valves and uniflow engines oil consumption.

 

Valve stem seals and tighter bore tolerances have virtually eliminated oil consumption on engines now compared with the 60s when there would be a plume of blue smoke from cars waiting at traffic lights.

[Stubby]

1 hour ago, openspaceman said:

I remember his design, a similar rotating valve in the head but it was conical.

 

At the end of 1940s the piston engine had just about peaked with things like the rotary valved sabre and even the diesel nomad but jets just eclipsed them. Much of the reason the techniques (other than multiple valves per cylinder and double overhead cams which are ubiquitous now) didn't transfer to commercial engines was the reliability and in the case of rotary valves and uniflow engines oil consumption.

 

Valve stem seals and tighter bore tolerances have virtually eliminated oil consumption on engines now compared with the 60s when there would be a plume of blue smoke from cars waiting at traffic lights.

I always thought the rotary JPS Nortons ( Brian Crighton ) would have set a trend . They seemed to equate to about 600cc and were destroying the current 750cc bikes but it never happened . 

[Macpherson]

3 hours ago, openspaceman said:

I remember his design, a similar rotating valve in the head but it was conical.

 

At the end of 1940s the piston engine had just about peaked with things like the rotary valved sabre and even the diesel nomad but jets just eclipsed them. Much of the reason the techniques (other than multiple valves per cylinder and double overhead cams which are ubiquitous now) didn't transfer to commercial engines was the reliability and in the case of rotary valves and uniflow engines oil consumption.

 

Valve stem seals and tighter bore tolerances have virtually eliminated oil consumption on engines now compared with the 60s when there would be a plume of blue smoke from cars waiting at traffic lights.

 

Yep, if I remember correct Frank's test bed was a Velocette, there's an old book out there called ' valve mechanisms for high speed engines ' by P Smith which documents the details of many of the alternative valve mechanisms that were conceived, designed and tried out as early as more than a century ago.

I've wanted a copy all my life but they are very scarce now and command a high price when they do appear, cheers.

[bmp01]

15 hours ago, Stubby said:

I always thought the rotary JPS Nortons ( Brian Crighton ) would have set a trend . They seemed to equate to about 600cc and were destroying the current 750cc bikes but it never happened . 

They had their own set of problems.  A well named gas company ran them at their research station on natural gas for an intended combined heat and power package. Reason being natural gas fuelled IC engines had issues with valve seat and stem wear at the time. Mechanically the rotor tip seals didnt last and the race track shaped rotor housing got all lumpy and bumpy. Apart from that the combustion chamber was a bit rubbish, emissions and oil consumption poor.

Mazda have given it a good go too but clearly they haven't taken over the world with it.

 

Good power though so all good for short life race engine.

[Stere]

Ones being developed for millitary UAVs

 

mentions a solution for the seal issues

 

Liquidpiston - Wikipedia

EN.WIKIPEDIA.ORG

 

 

LiquidPiston Awarded $9M Contract from DEVCOM Army Research Laboratory for Compact Efficient Rotary Engine Program

WWW.GLOBENEWSWIRE.COM

---

New engine will address Army’s Modernization Priorities...

 

[GarethM]

That's just a variation on the Wankel engine design. Every engine design is a comprise between efficiency and complexity, they aren't sitting on some mythical 5000 mpg engine with 1 moving part.

 

It's probably better to just return to low rpm and high torque, a F1 car engine is designed to last one race a 400rpm diesel thumper is designed to outlive us all.

 

They even had diesel RC plane engines in the 50/60s

Edited January 4, 2023 by GarethM

[Stubby]

1 hour ago, bmp01 said:

They had their own set of problems.  A well named gas company ran them at their research station on natural gas for an intended combined heat and power package. Reason being natural gas fuelled IC engines had issues with valve seat and stem wear at the time. Mechanically the rotor tip seals didnt last and the race track shaped rotor housing got all lumpy and bumpy. Apart from that the combustion chamber was a bit rubbish, emissions and oil consumption poor.

Mazda have given it a good go too but clearly they haven't taken over the world with it.

 

Good power though so all good for short life race engine.

Mate of mine had the Mazda for a short time . It got nicked ( or he had it nicked )