ROLLS-ROYCE CRECY

[Unregistered]

Re: ROLLS-ROYCE CRECY

None of this is true, marine diesels put out around 80-100 bhp per 1000 rmp and litre displacement, i.e. about 5 times a turbocharged formula one car :-) .. thus big two strokes are the worlds highest performing engines.

B.t.w. the Crecy was to some extent built to compete against the turbojet's since rollsroyce didn't have control of the patent, however they managed to screw Whittle over so he didn't get nothing for his contributions .. thus the crecy died.

But if you look at the power to wheight, it can match most of the modern bypass engines and certainly has better fuel economy !

i've heard that once a two stroke reaches a certain size in cu. in.'s it's ability to prduce more power than a four stroke dies, is this true?

if so, how did the crecy produce 5000 hp?

[Unregistered]

Re: Big two strokes

You mean like this house-size monster? (2-story house, that is...)

http://www.bath.ac.uk/~ccsshb/12cyl/ <--click here to see it!

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The Most Powerful Diesel Engine in the World!

"The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today. "

"The cylinder bore is just under 38" and the stroke is just over 98". Each cylinder displaces 111,143 cubic inches (1820 liters) and produces 7780 horsepower."

"14 cylinder version:
Total engine weight: 2300 tons (The crankshaft alone weighs 300 tons.)
Length: 89 feet
Height: 44 feet
Maximum power: 108,920 hp at 102 rpm
Maximum torque: 5,608,312 lb/ft at 102rpm
"

That's a BMEP of 544 psi!!!!!!

Welcome to the wonderful world of two strokes. Four strokes are doomed... <LOL>

Truth is, the 4S has one (and ONLY one) advantage over the direct injected 2S: operating range. In every other respect the 2S wins out. SFC, power density, power to weight, TBO, etc. Name it, except for wide operating range and widely varying load conditions, and the 2S beats the 4S every time. 2S engines got their bad rep from carburation and poor fuel-air management. In the real world of engines that have to make money for their manufacturers, 2S are equal or superior to their 4S brethren and mostly win out.

I myself was a 4S snob until about two years ago. I had studied enough and done enough engine development that when a person I repsected said "why NOT a 2S?", I set out to show him and came up with an answer that I didn't expect. Knowing the thermodynamics of tubine engines as well, I didn't expect the next answer.

The most efficient engine on the face of the earth is a "combined cycle" using a Brayton compression and expansion cycle on either side of an Otto cycle 2S piston engine. Whether compounded (Brayton cycle coupled to the power shaft) or free (Brayton cycle un-coupled), the efficiency and power density blows every other option to bits.

The issue that keeps 2S engines in the background of 4S is simple. We need engines with wide operating ranges for most uses in our everyday life. Cars, trucks, motorcycles, boats, etc. all need engines that function well under a 10:1 or greater idle to max power range. Our average car produces ~5 HP in stop and go traffic at an SFC of <.45 and still manages 200 HP at under .50! No 2S can do this.

Take that idle-to-max HP requirement to less than 5:1 and the 2S shines. Over a narrow operating range, the combined cycle 2S can achieve 50% or more improvement over the 4S in SFC and power density.

So who uses narrow operating range engines? Aircraft.

Because props on any aircraft function at a very narrow range of RPM and the power levels from take off to cruise do not vary more than 2:1, aircraft are an excellent cnadidate for highly efficient, high power density, narro operating range 2S technology. The average GA aircraft sees 2700 to 2300 RPM from takeoff to climb to cruise to descent. That's only a 16% variance in RPM and a 50% variance in power. Less than one fourth that of the worst car engine.

In load range, the aircraft engine uses 75 to 100% of the air available at any time (for a given altitude) unless we are descending. The car engine uses as little as 10%, but still must be able to operate efficiently at 100%.

Clearly, the aircraft (and air racing ) world screams for a 2S engine. The problem is that no one else does and aircraft are a small market. Hopefully, the market has and will continue to expand enough to make development of a superior 2S engine viable.

Eric Ahlstrom

[Peashooter]

Re: Big two strokes

In load range, the aircraft engine uses 75 to 100% of the air available at any time (for a given altitude) unless we are descending. The car engine uses as little as 10%, but still must be able to operate efficiently at 100%.

Clearly, the aircraft (and air racing ) world screams for a 2S engine. The problem is that no one else does and aircraft are a small market. Hopefully, the market has and will continue to expand enough to make development of a superior 2S engine viable. Eric Ahlstrom

Perhas the introduction of a "Superbore" class can enable such development. The IO-12 is a great start and OEMs like Lycoming and Thielert are at Reno to develop, then deploy new technologies! (At least new to Gen-Av.) To that end, I hope that the rule makers don't stifle development.

[Bill Marsh]

Re: ROLLS-ROYCE CRECY

HEY PISTON HEAT

look at all those big prime movers..... marine and stationaey...... with gaggles of oil injection tubes w/underside honeycombs to cold soak all that piston heat away...... on other away i guess

BMarsh

[Bill Marsh]

Re: ROLLS-ROYCE CRECY

SUGGESTION TO MODERATOR


Move this to the regular board for more action


this thread is "lost in space" at the bottom of the web site menu!!!!

BMarsh

[First time Juke]

Re: ROLLS-ROYCE CRECY

You mean like this house-size monster? (2-story house, that is...)

http://www.bath.ac.uk/~ccsshb/12cyl/ <--click here to see it!

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The Most Powerful Diesel Engine in the World!

"[i]The Wartsila-Sulzer RTA96-C turbocharged two-stroke diesel engine is the most powerful and most efficient prime-mover in the world today. "

That is a finnish engine...Wartsila makes those Caribbean Cruise liners a lot.

[Feliks]

Re: ROLLS-ROYCE CRECY

Crecy was half way.

This is next part





http://www.new4stroke.com

Regards Andrew

[Feliks]

Re: ROLLS-ROYCE CRECY

That is a finnish engine...Wartsila makes those Caribbean Cruise liners a lot.

And so the engine can be replaced Crecy its second half and the engine of the Caribean lines?





Are You know engine named Twin Feliks ?






So 10 (40) "cylindrical" engine half rotate about the same working capacity in comparing to the Sulzer 10 engine cylindrical on the picture below .

Sulzer: 10 Cylinders 20 m long , 15 m hight , 1500 Ton weight

Half rotate star : 10(40) "Cylinders" 4,5 m diameter , 4,5 m long
about 70 ton weight.


And most importantly.. Since in the engine half rotate mass innertia are several times Sulzer smaller than in the engine, engine half rotate can work with the much greater rotation speed.
Sulzer : 102 RPM 60 000 KW

Half rotate 250 RPM 150 000 KW

In same intake work volume .

Regards Andrew

[First time Juke]

Re: ROLLS-ROYCE CRECY

Andrew I am not sure what you are after, but the axial vector engine is the most efficient in size / output.

Do a google search.

Many Caribbean Cruise liners are made in Finland ( Oasis of the Seas, Freedom of the Seas etc ) but most are labelled STX yard ships of South-Korea.

[Feliks]

Re: ROLLS-ROYCE CRECY

Andrew I am not sure what you are after, but the axial vector engine is the most efficient in size / output.

Do a google search.

Many Caribbean Cruise liners are made in Finland ( Oasis of the Seas, Freedom of the Seas etc ) but most are labelled STX yard ships of South-Korea.

If You not shure , put in Google Andrew Feliks

I am confident that my design of the valves is lighter than traditional.



Diameter popped 75 mm , diameter piston 76.5 mm




Weight popped 75 mm 1000 G
weight piston & rod 76.5 mm 850 G
weight popped 62 mm 400 G
weight piston & rod 62 mm 370 G

But the window of the flight of the valve of 75 mm is only 64 mm, what is very similar to the window of the flight piston 62 mm .

That is it results from it that the valve of 75 mm is giving the same flight as the piston 62 mm that is 1000 G to 370 G !!!!!

==~~ 2.5 more weight popped to piston& rod !!

It only looks impossibly. but this way is.





In principle ,for them greater popped/piston diameter, it is this difference in weight will be to the benefit of pistons.

Regards Andrew

[First time Juke]

Re: ROLLS-ROYCE CRECY

Andrew Feliks !

Isn't that engine of yours quite complicated and difficult to cool down in an aeroplane like Dart where E.Ahlstrom originally dreamed this Crecy in to propel a pusher fan like mr.Lear did some 35 year ago ( Learfan 2100 ).

I saw your site...the new cellphone without rechargeable traditional batteries looks cool. I applied a patent also for such a thing in 2003...no one here was interested back then. Also your ideas to close the oil spill in the Caribbean seemed interesting.

I think there is a much simpler engine with mucho hp:s and twinengine reliability doable for a contraprop pusherfan..much like the Mixmaster in 1948...unlike the looks of it..a real speedster...maybe the p-75 Fisher Eagle could give some interesting glues to go forward. One thing is certain..it takes a lot of money to develop a plane and engine to go 560-600 mph with a piston engine reliably ( and extremely economically ) and carry 10-16 passengers...and still go to airport if the other engine quits ( isn't this that partially ended Learfan project...FAI did not allow it to operate with just one prop and two engines ).

Later,

Juke

[Feliks]

Re: ROLLS-ROYCE CRECY

Beautiful simple new 4 stroke kinematics animation made at the
King Soud University.




And a little faster



Regards Andrew

[Feliks]

Re: ROLLS-ROYCE CRECY

Well, who would have thought that Newcomen was so close to an adequate solution :blink:






Regards Andrew

[Feliks]

Re: ROLLS-ROYCE CRECY

I also very close to the Technology


Regards Andrew

[Exhaustgases]

Re: ROLLS-ROYCE CRECY

Most of those alternative engines look good in photo's, but in actuality most all of them would suffer from heat loss, through all the extra area.
Its a surface area to volume deal, and that is where the huge marine and stationary Diesel engines shine. One of the reasons they are so effcient.
Also with the alternative engine designs, the cost and complication of the parts manufacture, is a huge point against them. Just look at the complexity of the Wankel type engine as far as the rotor and sealing goes.