Engine technology free-for-all

[Brian Coat]

These fuels have detonation velocities >6km/s and detonation pressures in the 10s of GPa so if they really go, they really go.

Even "ordinary" nitro can perform the block splitting trick.

I once saw it happen during an attempt to restart an A Fueler (unblown nitro) after being shut down for rain spots.

For a nitro burner, A Fuelers run relatively high compression ratio (>11:1) and are usually started on methanol and switched to nitro as the engine warms up but on this occasion the shutdown had left some nitro in the cylinders prior to re-crank.

There was a bang and the block was split clean in two. The driver legged it pretty fast.

The remains of the engine drew a lot of attention in the pits!

I've seen people try to hand crank the engine over backwards a few times to clear the "fuel" out of the cylinders after a shutdown but that theory did not work out too well on this occasion ...

[Brian Coat]

OK, so in the spirit of 'free for all', what would people specify/create if ultimate efficiency was the goal and there were no constraints ... at all?

[Blanchimont]

Optimised for a F1 race car or a container ship?

[Brian Coat]

Blanchimont: Thank you for asking.

I meant F1 but answer both if the spirit takes you there!

[OdinYggd]

70 cc's ... 5 hp ...

http://www.speednik.com/files/2014/11/l ... 40x426.jpg

http://www.enginelabs.com/news/liquidpi ... ry-engine/

Looks to me like they turned the wankel engine inside out.

This actually solves one of the biggest problems the wankel rotary has- the fact that a part of the fuel is in front of the flame and moving away from it, leading to a longer burn duration that overall decreases efficiency and effective expansion ratio.


I still need to get my own prototype running.
What I have is a piston engine that achieves a 4-stroke cycle using only 3 moving parts and fires twice per revolution per cylinder. 1:1 power to weight ratio should be possible even with an all steel construction.

After 5 years of testing and out of pocket R&D, I have a crude prototype that demonstrates the operating cycle and produces a beautiful blue cloud of fire off the exhaust header even though it still doesn't run.

Whats been staring me in the face for most of that 5 years is that my ignition system wasn't working reliably- there's a very good chance that in the most recent tests it has only ignited perhaps once every 3rd or 4th power stroke. My breaker point mount would vibrate at cranking speed, and the points themselves would sometimes weld shut and overheat the ignition coil.

A solid state ignition driver is being fitted that will let the engine use a magnetic pickup or even a rotary encoder to allow for coupling to a homemade ECM. With this revision there's a good chance it will actually run on its own for the first time, despite having been made almost entirely out of scrap steel on a tight budget.

[gruntguru]

Look forward to a video when it is running. Assuming the video doesn't have to disclose any secrets.

[J.A.W.]

Look forward to a video when it is running. Assuming the video doesn't have to disclose any secrets.

Me too, & by.. "running".. I mean as an actual ICE, not a externally motored pipe-dream..

[OdinYggd]

Look forward to a video when it is running. Assuming the video doesn't have to disclose any secrets.

Hoping to be able to at some point. Will probably have to fit covers to a few sections of it to conceal the working mechanism.

Before that though I need to get it to actually run. Right now it just spits fire and makes noise when spun using a power drill.

[J.A.W.]

Forbidden fruit - Bishop rotary valve - banned for F1..

http://home.people.net.au/~mrbdesign/PD ... echBRV.pdf

[uniflow]

Lets get real, a twostroke engine would have to be first choice. POWER to WEIGHT can't be beat. New developments now have reed induction engines making as much as rotary valve engines. New cylinder porting layouts ( also new developments ) will be pushing 125cc engines in the region of 60HP ( natural aspiration ) this in anyones terms is fantastic. More power than a 450 fourstroke MX bike and one hell of a lot cheaper to run.

[J.A.W.]

Yeah, Uniflow, for a piston mill, that fundamental/inherent X2 BMEP 2-stroke advantage is just killer..
..& for cost/complexity/mass.. ..induction pressure/cubic capacity/fuel - being equal..

[tuj]

anyone thinking 2-stroke turbo? Scavenging should be much better, no?

[wuzak]

Ricardo was the main driver behind sleeve valves in British industry and government circles, as he was on teh board overseeing the development of British Aero engines.

He was also, in th elate '20s/ear;y '30s a proponent of Diesel engines. One reason given was the lower flammability of Diesel fuel than petrol. Another was the knock limits that high performance engines were running into at the time, something which would not affect Diesels.

To that end he converted, with some help from Rolls-Royce, two Rolls-Royce Kestrels into sleeve valve compression ignition engines. These were designated RR/D by Ricardo.

These were unsupercharged and had disappointing performance.

The RR/D produced only 350hp @ 2250rpm and had many issues with the mechanical components, such as the big end bearings, because they were not designed for such high cylinder pressures.

At the request of the Air Ministry on of the RR/Ds was to be converted back to spark ignition, and was renamed RR/P. This work seems to have been largely done at Rolls-Royce Derby.

In addition to the required parts for spark ignition operation, a standard Kestrel single stage supercharger was fitted. The RR/P managed 680hp @ 3000rpm in testing, bettering the standard Kestrel of the day and being not far shy of the ultimate Kestrel, the 720hp XXX (from the late 1930s).

There were issues with the RR/P including overheating of the piston and sleeve.

The sleeves used by RR/D and RR/P were similar to those of Bristol and Napier, and were used in conjunction with a junk head.
I'm not sure of teh cylinder dimensions for RR/D and RR/P.

[Brian Coat]

Two stroke turbo sounds fun.

How about a gas turbine hybrid?

Efficiency at such a 'low' power level would be an issue though ...

[autogyro]

Two stroke turbo sounds fun.

How about a gas turbine hybrid?

Efficiency at such a 'low' power level would be an issue though ...

How about an electric/turbine hybrid VTOL multi roll supersonic combat aircraft.
I could build you one of those.