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#51 Grumbles

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Posted 28 December 2009 - 20:53

I checked out the http://www.detroitdi...15/default.aspx

they are still being made and is claimed to make the emission demands.


These engines (and the Series 60) are four strokes with electronic management systems. By modern standards the old 53,71,92 and 110 series two-strokes are very dirty and thirsty.


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#52 gruntguru

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Posted 29 December 2009 - 06:52

Lets say fuel made of chicken fat/ or alkohol out of corn is greener than oilfield diesel that gives a + letting the chicken fuel/corn alcohol cars carry more or diesels less.


I believe someone recently presented a conference paper on alternative fuels for diesels including some testing they had done with oil derived from human fat (by-product of liposuction procedures.) I think it would be greener to ban the patients from Macca's.

#53 MatsNorway

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Posted 29 December 2009 - 07:20

These engines (and the Series 60) are four strokes with electronic management systems. By modern standards the old 53,71,92 and 110 series two-strokes are very dirty and thirsty.


Where did you get that from?

I believe someone recently presented a conference paper on alternative fuels for diesels including some testing they had done with oil derived from human fat (by-product of liposuction procedures.) I think it would be greener to ban the patients from Macca's.


haha lets recycle dead people.

Edited by MatsNorway, 29 December 2009 - 07:29.


#54 gruntguru

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Posted 29 December 2009 - 07:52

The racetrack is a terrible place to research new technologies for roadcars.


Maybe so, but it is an industry which currently spends millions (perhaps billions) on innovation and development. A stroke of the pen (or mouse) at FIA could divert a percentage of that effort from chasing minute aero increments towards something that might ultimately benefit society.

Posters decrying fuel limits are missing the point. If a fuel limit or rate limit is imposed as the means of restricting power, the race to increase power can only be won by increasing efficiency. So, impose a fuel limit and/or a rate limit and free up all the other regulations governing engine and drivetrain. Set the initial limit at a level that preserves current speeds or slightly lower. As technology progresses, change the fuel limit to maintain speeds. This would have to be the easiest method ever for adjusting race speeds. In the past we have seen all manner of artificial impositions used to reduce speed - reduce displacement, limit number of cylinders, limit RPMs, ban turbo's, ban exotic materials - all difficult and costly to implement, and all anti-innovation.

I do not subscribe to the "motorsport doesn't create" philsophy. There are countless examples where motorsport has accelerated important, relevant technologies - electronic management, composite construction, tyres, brakes . . . .

Free up the engine and drivetrain regulations. Reward the teams who can extract more power from their fuel ration.

#55 gruntguru

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Posted 29 December 2009 - 07:59

Where did you get that from?


It's a fact. None of the engines on Detroit's website are 2-strokes. Interesting though, its less than 10 years since I last saw them there. They were still sold alongside the 60 series for a long time although I think much of that was "export only" because they couldn't even meet emission standards for industrial engines.

haha lets recycle dead people.


Very wasteful to feed dead people to diesel engines. Didn't you see "Soylent Green"?

Edited by gruntguru, 29 December 2009 - 08:00.


#56 MatsNorway

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Posted 29 December 2009 - 12:59

It's a fact. None of the engines on Detroit's website are 2-strokes. Interesting though, its less than 10 years since I last saw them there. They were still sold alongside the 60 series for a long time although I think much of that was "export only" because they couldn't even meet emission standards for industrial engines.


You need to back it up with facts (links) i am pretty sure i was reading some were that ship motors of this type was having a good efficiency.



Very wasteful to feed dead people to diesel engines. Didn't you see "Soylent Green"?


Never heard of it. Is that some strange sci fi movie?

about water injection, that`s a think that should be legalized in some motor sport genre. No CO2 there.

#57 Grumbles

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Posted 29 December 2009 - 21:41

You need to back it up with facts (links) i am pretty sure i was reading some were that ship motors of this type was having a good efficiency.


Modern marine 2 strokes can certainly be very efficient. But they have nothing to do with the old Detroits/GMs, some of which have changed very little since the late 1930s.
The big Sulzer marine 2 strokes achieve 0.28lb/hp/hr, the old GMs are nowhere near this - typically more like 0.45lb/hp/hr or more.
I still work on the old Detroits nearly every day, and they do have some advantages. The closely spaced firing impulses are gentle on drivelines. And until fairly recently they were very competitive with regard to power:weight and power:bulk ratios. I'll miss them when we replace the last of them with Cummins engines. But they are definitely filthy, thirsty engines.

Heres a 6V:53T in an altered dragster, doing an 8.72sec. run.


#58 MatsNorway

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Posted 31 December 2009 - 11:01

Modern marine 2 strokes can certainly be very efficient. But they have nothing to do with the old Detroits/GMs, some of which have changed very little since the late 1930s.
The big Sulzer marine 2 strokes achieve 0.28lb/hp/hr, the old GMs are nowhere near this - typically more like 0.45lb/hp/hr or more.
I still work on the old Detroits nearly every day, and they do have some advantages. The closely spaced firing impulses are gentle on drivelines. And until fairly recently they were very competitive with regard to power:weight and power:bulk ratios. I'll miss them when we replace the last of them with Cummins engines. But they are definitely filthy, thirsty engines.

Heres a 6V:53T in an altered dragster, doing an 8.72sec. run.


ok.

what they call those marine motors, what brands etc.

#59 gruntguru

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Posted 31 December 2009 - 11:58

ok.

what they call those marine motors, what brands etc.


Wartsila
Sulzer
MAN B&W

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#60 MatsNorway

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Posted 31 December 2009 - 16:26

Wartsila
Sulzer
MAN B&W



thanks

#61 Greg Locock

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Posted 01 January 2010 - 05:33

Maybe so, but it is an industry which currently spends millions (perhaps billions) on innovation and development. A stroke of the pen (or mouse) at FIA could divert a percentage of that effort from chasing minute aero increments towards something that might ultimately benefit society.

I do not subscribe to the "motorsport doesn't create" philsophy. There are countless examples where motorsport has accelerated important, relevant technologies - electronic management, composite construction, tyres, brakes . . . .


So, when you are doing the world shaking research that justifies this opinion, do you really find having the added impetus of having to get a competitive car on the track in two months time in order to pay the bills helps the quality of your research efforts?

I've rarely worked on blue sky research, but have worked on a lot of implementation phase stuff, the two are completely different animals.



#62 cheapracer

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Posted 01 January 2010 - 07:15

Very wasteful to feed dead people to diesel engines. Didn't you see "Soylent Green"?


I prefer "Soylent Yellow" wafers myself - Chinese take away :lol:




#63 cheapracer

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Posted 01 January 2010 - 07:34

I actually agree that those who promote or buy into the primacy of the drivers' competition as opposed to the technical competition are probably not really qualified or entitled to be called motorsports fans. It seems they would be far better served following say track and field where cars are of no importance at all rather than bemoaning equipment inequalities in a sport where they are not only inevitable but integral and central to the sport.


I guess we should just punch all the specs of the cars into a computer and just run simulations solving the green issues in one swoop.

#64 gruntguru

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Posted 02 January 2010 - 07:47

So, when you are doing the world shaking research that justifies this opinion, do you really find having the added impetus of having to get a competitive car on the track in two months time in order to pay the bills helps the quality of your research efforts?


Either I'm missing your point entirely or you're missing mine.

Do the F1 R&D billions make the cars faster each year?

If the F1 rules were changed such that energy efficiency became crucial to track performance, would the F1 R&D billions advance the state-of -the-art for automotive energy efficiency?

#65 DaveW

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Posted 02 January 2010 - 09:56

So, when you are doing the world shaking research that justifies this opinion, do you really find having the added impetus of having to get a competitive car on the track in two months time in order to pay the bills helps the quality of your research efforts?

I've rarely worked on blue sky research, but have worked on a lot of implementation phase stuff, the two are completely different animals.

I'm sorry, Greg, but you paint a very traditionalist picture, one that presupposes the OEM's have all the answers &, consequently, nobody else can make a useful contribution.

I think that perhaps "unencumbered thinking" rather than "blue sky research" might be a more appropriate phrase to use in the present context.

I am reminded of the abortive APT (advanced passenger train), which was a UK project started around 50 years ago employing aerospace engineers who introduced tilting carriages, regenerative braking, stable wheel/bogie designs & several other novelties, many of which are incorporated in today's high speed trains. BRE, traditionally responsible for train designs, were so against the project that, so it was rumoured, they actually sabotaged cable looms on the prototype to ensure that the project and its technology was ultimately scrapped as being too unreliable. The end result is that the UK now imports 100 percent of its rail stock.

Perhaps that is an extreme example. Another example, one with which I was closely associated, caused me to conclude that road vehicle OEM expertise is much too "focused" to make a success of a novel project (at least in a short time frame) without considerable external stimulus & assistance.

I believe hybrid drive technology falls into that category, & motor racing could provide the necessary development stimulus unencumbered by back seat show stoppers such as "we don't use those transducers", "we can't use that type of cable", "we couldn't adopt that layout", "those parts are not on our approved list", etc.

Edited by DaveW, 02 January 2010 - 10:04.


#66 Greg Locock

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Posted 03 January 2010 - 01:50

I'm sorry, Greg, but you paint a very traditionalist picture, one that presupposes the OEM's have all the answers &, consequently, nobody else can make a useful contribution.


I believe hybrid drive technology falls into that category, & motor racing could provide the necessary development stimulus unencumbered by back seat show stoppers such as "we don't use those transducers", "we can't use that type of cable", "we couldn't adopt that layout", "those parts are not on our approved list", etc.


I don't believe OEMs have the answers and have always railed against the conservatism of every auto manufacturer I have ever worked for, except Rover, oddly.

The fact is that the only successful hybrid system in the world was developed by a very conservative OEM, based on a paper that was published in 1971. No race team has made a useful contribution to the field of hybrid technology, and I wouldn't expect them to. Incidentally if a development team isn't using Systems Engineering properly then frankly I am not interested in their approach.

Edited by Greg Locock, 03 January 2010 - 02:22.


#67 gruntguru

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Posted 03 January 2010 - 07:24

No race team has made a useful contribution to the field of hybrid technology, and I wouldn't expect them to.


Why would they, when in general the rules don't just discourage hybrid technology - they prohibit it! (FSAE hybrid is a notable exception)

#68 Pingguest

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Posted 17 January 2010 - 18:06

Why?


In the near future the demand for fuel efficiency and sustainability explode again. In case Formula 1 would leave the engines free, ban fossil fuels and limit energy consumption, its manufactures would have to develop new technologies that will meet the future consumer's demands.

Ultimate drivers championship my a**.

Ferenc Szisz didn't the win first official Grand Prix in 1906 because he was the ultimate driver, it's because his car was reliable and more advanced, and he could do pit stops in 2-3 minutes (detachable wheel rims) when others need 15 minutes.
The others lost the same way Massa lost the WDC in 2008, at the pits.


I always opposed mid-race refuelling, because it was against fundamental principles of the sport. Since World War II motor sport has been divided into two categories: one for the drivers and one for the manufactures. Formula 1 is in the first category: the series had no constructors' championship until 1958 and until then not the drivers but their cars were changed during the race.

#69 Tony Matthews

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Posted 17 January 2010 - 21:33

In the near future the demand for fuel efficiency and sustainability explode again. In case Formula 1 would leave the engines free, ban fossil fuels and limit energy consumption, its manufactures would have to develop new technologies that will meet the future consumer's demands.


No other sport is expected to contribute in this way. Far more fuel/energy would be saved by people making fewer journeys and driving sensibly.



I always opposed mid-race refuelling, because it was against fundamental principles of the sport. Since World War II motor sport has been divided into two categories: one for the drivers and one for the manufactures. Formula 1 is in the first category: the series had no constructors' championship until 1958 and until then not the drivers but their cars were changed during the race.

What fundamental principles?

The teams regard the Constructors Championship as very important, often more than the Drivers Championship. Obviously the aim is to win both.

#70 imaginesix

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Posted 17 January 2010 - 21:43

No other sport is expected to contribute in this way. Far more fuel/energy would be saved by people making fewer journeys and driving sensibly.

Why does it have to be either/or? How 'bout both?

#71 Wuzak

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Posted 18 January 2010 - 01:37

I always opposed mid-race refuelling, because it was against fundamental principles of the sport. Since World War II motor sport has been divided into two categories: one for the drivers and one for the manufactures. Formula 1 is in the first category: the series had no constructors' championship until 1958 and until then not the drivers but their cars were changed during the race.


Interestingly refuelling has played a part in GPs for many years.

In the period 1950-1957 where there was no constructors championship there was refuelling.

In 1935 when Nuvolari won the German GP he had refuelling dramas that delayed him. Similarly, in 1957 when Fangio won the German GP he was famously delayed when he stopped for fuel and tyres. The cars he beat, the Ferraris of Hawthorn and Collins, had elected to not stop and take on fuel or tyres. That wasn't an option for Fangio.

Surely since the very first motor race the idea was to for manufactirers/teams to make better cars than the opposition?

#72 Tony Matthews

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Posted 18 January 2010 - 08:59

Interestingly refuelling has played a part in GPs for many years.

In the period 1950-1957 where there was no constructors championship there was refuelling.

In 1935 when Nuvolari won the German GP he had refuelling dramas that delayed him. Similarly, in 1957 when Fangio won the German GP he was famously delayed when he stopped for fuel and tyres. The cars he beat, the Ferraris of Hawthorn and Collins, had elected to not stop and take on fuel or tyres. That wasn't an option for Fangio.

Surely since the very first motor race the idea was to for manufactirers/teams to make better cars than the opposition?

To that I would add, employ tactics, within the rules, that give you an edge. That could be just making the right call on whether or when to change from wet to dry tyres, or vice versa.

#73 MatsNorway

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Posted 29 January 2010 - 19:24

I WANT WANKEL in F1!




http://www.youtube.c...player_embedded

http://www.youtube.c...feature=related

http://www.youtube.c...feature=related



Pretty effin badass sound ee?

#74 Greg Locock

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Posted 30 January 2010 - 01:08

I WANT WANKEL in F1!

Do you want a pony for your birthday as well?



#75 Catalina Park

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Posted 30 January 2010 - 06:18

I WANT WANKEL in F1!

Nobody has ever built a successful Wankel engine. (success = profit)
Mazda only makes them because their culture will not allow them to admit failure. The same reason that Subaru uses boxers and Toyota blamed the floor mats.


#76 gruntguru

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Posted 30 January 2010 - 06:27

I WANT WANKEL in F1!

I think you'll have to remain contented doing it in front of your computer.

#77 MatsNorway

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Posted 30 January 2010 - 10:07

Negative Negative Negative Negative


Cool sound or what?



#78 Tony Matthews

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Posted 30 January 2010 - 10:27

I WANT WANKEL in F1!




http://www.youtube.c...player_embedded


All I can hear is an engine that is not running cleanly.

http://www.youtube.c...feature=related



Pretty effin badass sound ee?

If you are excited by that you are easily pleased. Perhaps you have never heard a V12 Ferrari F1 engine in real life, and you should check the BRM V16 on youtube. If you prefer a wankel, that's your choice.

#79 MatsNorway

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Posted 30 January 2010 - 11:27

All I can hear is an engine that is not running cleanly.


If you are excited by that you are easily pleased. Perhaps you have never heard a V12 Ferrari F1 engine in real life, and you should check the BRM V16 on youtube. If you prefer a wankel, that's your choice.


I have the cd with the BRM V16. Sounds Badass!

but its kinda in a different category. can`t compare these engines.

this one is king but i think most of you have heard it before.



Edited by MatsNorway, 30 January 2010 - 11:28.


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#80 Wuzak

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Posted 08 February 2010 - 07:13

I have the cd with the BRM V16. Sounds Badass!

but its kinda in a different category. can`t compare these engines.

this one is king but i think most of you have heard it before.



This one gives a better indication of sound, I think.

http://www.youtube.c...feature=related

"F1 cars have copied it's sound!!!" :lol:

Hmmmm

http://www.youtube.c...feature=related (not an F1 car but an F1 engine)


#81 J. Edlund

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Posted 08 February 2010 - 15:26

Couldn't they just run them on nuclear fission or some other exotic powersource? It is an exclusive formula after all.


An operating nuclear reactor create neutron radiation which would require a very heavy radiation shield, the same problem that prevented nuclear propulsion in aircraft.


#82 MatsNorway

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Posted 08 February 2010 - 16:28

An operating nuclear reactor create neutron radiation which would require a very heavy radiation shield, the same problem that prevented nuclear propulsion in aircraft.


nonesense! radiation is good for you.

Its just as apples.

A apple a day keeps the doctor away.

those linkylinks were from spam machines.com

Just post the direct download link please. its not rocket science if you know were it is.

Edited by MatsNorway, 08 February 2010 - 16:30.


#83 Tony Matthews

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Posted 08 February 2010 - 17:16

nonesense! radiation is good for you.

It's good to know that you have volunteered to clean up the reactor at Chernobyl single handed. Good in more sense than one...

#84 Wuzak

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Posted 08 February 2010 - 20:44

An operating nuclear reactor create neutron radiation which would require a very heavy radiation shield, the same problem that prevented nuclear propulsion in aircraft.



And yet....

http://en.wikipedia....lear_Propulsion
http://en.wikipedia....-36#Experiments

The Convair XB-36H made several flights with a functional nuclear reactor on board. It may have even flown with the reactor opertaing, but the nuclear propulsion system was not used.



#85 gruntguru

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Posted 09 February 2010 - 01:47

@wuzak: Yeah it did fly with a nuclear reactor but quote:

"modified to carry a 1 MW, air-cooled nuclear reactor in the aft bomb bay, with a four ton lead shield between the reactor and the cockpit. The cockpit was encased in lead and rubber... " etc.

Seems a long way short of a powerplant that could actually propel that particular aircraft since its conventional propulsion system consisted of more than 15 MW worth of piston engines.

Edited by gruntguru, 09 February 2010 - 01:48.


#86 Wuzak

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Posted 09 February 2010 - 01:55

Seems a long way short of a powerplant that could actually propel that particular aircraft since its conventional propulsion system consisted of more than 15 MW worth of piston engines.



It was a test bed, designed to see ifi t was feasible to carry a nuclear reactor and also to test the few different propulsion jets that were to be used with the reactors.

#87 MatsNorway

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Posted 14 February 2010 - 18:56

ho said wankel was not competitive on power?

this awsome engine got 514hp.



The 787B had a 2622 cc and developed 700 hp

what was the power and displacement of the F1 cars in 1991?

Edited by MatsNorway, 14 February 2010 - 18:56.


#88 Wuzak

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Posted 14 February 2010 - 21:37

ho said wankel was not competitive on power?

this awsome engine got 514hp.



The 787B had a 2622 cc and developed 700 hp

what was the power and displacement of the F1 cars in 1991?



Power is not the problem with rotaries.

#89 gruntguru

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Posted 15 February 2010 - 00:19

The 787B had a 2622 cc and developed 700 hp


If you calculate the Wankel capacity correctly it comes to 7,866 cc. So less than 100 hp per litre.

These days you can walk into any Japanese motorcycle dealer and buy a street bike with more than 200 hp per litre.

#90 Wuzak

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Posted 15 February 2010 - 02:21

If you calculate the Wankel capacity correctly it comes to 7,866 cc. So less than 100 hp per litre.

These days you can walk into any Japanese motorcycle dealer and buy a street bike with more than 200 hp per litre.


Always confused by this.

As I understand it the 13B is rated at 1300cc per rotor, or 2600cc. So the 787B would be 5200cc?

Edited by Wuzak, 15 February 2010 - 02:22.


#91 gruntguru

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Posted 15 February 2010 - 03:51

Always confused by this.

As I understand it the 13B is rated at 1300cc per rotor, or 2600cc. So the 787B would be 5200cc?


The 13B displaces 654 cc per chamber. There are 3 chambers per rotor so 12 chambers on a 4-rotor. 12 times 654 = 7848 cc (not 7866 as stated in my original post.) This is the volume of air displaced by the engine during one complete cycle at 100% volumetric efficiency. All other methods of evaluating Wankel displacement are erroneous. (Mazda's use of 654 x 2 for the 13B has more to do with gaining a more favourable taxation status with the Japanese government who eventually taxed Wankels at half the correct value or 1.5 times Mazda's stated value)

#92 CSquared

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Posted 15 February 2010 - 06:47

The 13B displaces 654 cc per chamber. There are 3 chambers per rotor so 12 chambers on a 4-rotor. 12 times 654 = 7848 cc (not 7866 as stated in my original post.) This is the volume of air displaced by the engine during one complete cycle at 100% volumetric efficiency. All other methods of evaluating Wankel displacement are erroneous. (Mazda's use of 654 x 2 for the 13B has more to do with gaining a more favourable taxation status with the Japanese government who eventually taxed Wankels at half the correct value or 1.5 times Mazda's stated value)

This is one of those endless debates that never reaches consensus, probably because people won't agree on what constitutes a "cycle."

The logic that says the 787B's engine is equivalent to a 7848cc four-stroke piston is the same logic that says a 500cc two-stroke is equivalent to a 500cc four-stroke. Everyone knows there's more to it than that, and that for most purposes, it's an invalid comparison. It's equally invalid, for most purposes, to say that the 787B's engine was comparable to a 2616cc four-stroke piston engine or to say that it's comparable to a 7848cc four-stroke piston engine.

If you compare the number of power strokes per crankshaft revolution, a one-rotor Rotary has the same number of power strokes per crank revolution as a two-cylinder four-stroke piston engine, or a one-cylinder two-stroke piston engine.

However, the FIA equivalency formula rated the 787B's engine at 4708cc, not 5232cc. I believe this is because the real controversy is in how to calculate the displacement of one rotor face's power or intake stroke. It's not as simple as in a piston engine where you calculate the area of the piston face times its stroke, because the whole chamber is moving around the rotor face and changing shape and volume during the power and intake stroke, like if both the cylinder and the piston were moving relative to the crank in a piston engine. Rotor face times stroke is not equal to how much air the thing actually sucks in in its intake stroke. I don't even know if the FIA measured that when they came up with their equivalence, but somehow they came up with a 1.8 factor, not 2 or 3. But I'm no expert here and am happy to be corrected and/or taught.


#93 gruntguru

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Posted 15 February 2010 - 12:11

This is one of those endless debates that never reaches consensus, probably because people won't agree on what constitutes a "cycle."

A "cycle" is very easy to define. First observe a charge of intake air enter the engine, then follow that charge as it is squeezed, banged and blown. When that same cylinder or chamber begins to draw it's next charge of intake air, the engine has completed one thermodynamic cycle.

The logic that says the 787B's engine is equivalent to a 7848cc four-stroke piston is the same logic that says a 500cc two-stroke is equivalent to a 500cc four-stroke. Everyone knows there's more to it than that, and that for most purposes, it's an invalid comparison.

Who is this "everyone" you mention. Its certainly not the same "everyone" I know. Certainly 2 strokes and 4 strokes of equal capacity can't be rated equally for performance just the same as NA vs supercharged engines. That doesn't invalidate the method used for determining displacement. Unfortunately when Mazda originally published the displacement of their rotary, they departed from the correct method - nobody noticed at first - and now it's easier for everybody to live with the error.

It's equally invalid, for most purposes, to say that the 787B's engine was comparable to a 2616cc four-stroke piston engine or to say that it's comparable to a 7848cc four-stroke piston engine.

Well its displacement is the same as any positive displacement internal combustion engine that displaces 7848cc. Its cycle is 4 stroke. It's performance is different. It would probably need some help and probably couldn't compete with piston engines bigger than say 5,000cc. So perhaps a 1.5 equivalence would be a reasonable starting point. Hard to say because Wankels are very light and compact for a given displacement which would help compensate for their specific power disadvantage.

If you compare the number of power strokes per crankshaft revolution, a one-rotor Rotary has the same number of power strokes per crank revolution as a two-cylinder four-stroke piston engine, or a one-cylinder two-stroke piston engine.

The crank revolutions of a Wankel are pretty much irrelevant since there are gearing issues.

However, the FIA equivalency formula rated the 787B's engine at 4708cc, not 5232cc. I believe this is because the real controversy is in how to calculate the displacement of one rotor face's power or intake stroke. It's not as simple as in a piston engine where you calculate the area of the piston face times its stroke, because the whole chamber is moving around the rotor face and changing shape and volume during the power and intake stroke, like if both the cylinder and the piston were moving relative to the crank in a piston engine. Rotor face times stroke is not equal to how much air the thing actually sucks in in its intake stroke.

It is actually. There is a simple formula for Wankel displacement. The only conjecture is whether the displacement should be applied to each rotor once or three times. The only logical method is to apply the displacement to each chamber. The Wankel principle can be used to make an engine with other numbers of chamber on each rotor - four for example. Such an engine would displace 33% more than a 3 lobe Wankel and would have an obvious displacement advantage.

I don't even know if the FIA measured that when they came up with their equivalence, but somehow they came up with a 1.8 factor, not 2 or 3. But I'm no expert here and am happy to be corrected and/or taught.

The FIA equivalence factor is an arbitrary number which was hoped would produce reasonable parity in competition. Pretty much like the equivalence factor for supercharging which has been set at everything from 1.4 to 3.0 (and probably beyond) in various forms of racing.

#94 MatsNorway

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Posted 15 February 2010 - 16:36

I agree to most of gruntguru says.

Each chamber that sucks in air and bangs should count as a "piston" if all three chambers puffs all three chambers count in the displacement calculation.

How much water you could fill the intake chamber with at its biggest moment counts.

those two things is enough to determine size i think.

And the correct one.

When it comes to four stroke vs two stroke.

Its irrelevant how many times the engine does NOT fire. its its volume that matters.

so since im green on wankels, how many chambers/sides fills up on it?

all three?


If the 13B is a one rotor its displacement will be 1962cc.

How did NSU measure the engine volume?

sure they didn't start the bad trend?

Edited by MatsNorway, 15 February 2010 - 16:38.


#95 CSquared

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Posted 15 February 2010 - 19:26

Ok, I'll agree that for a strict definition of "the displacement used in a thermodynamic cycle" that's how you'd calculate it. But this issue was brought up by comparing the hp/(liter by this method) of the 787B to a 20-year-newer four-stroke piston and saying it's therefore poor and underpowered. I explained that I think that comparison is as weird/misleading/dumb as saying that a four-stroke engine is seriously underpowered/poor/inefficient because it gets roughly 1/2 the hp/l of a two-stroke (even without considering 20-year age differences).

So you guys think a 500cc two-stroke is comparable to a 500cc four-stroke, then. Or you think we should compare four-stroke piston engines to Rotaries revving 50% faster? Maybe in that comparison the Rotary will again come out looking pretty good?

Maybe we don't disagree about anything here and are just in another argument about terminology. Do we all agree that:
1. A 500cc two-stroke piston engine "pumps" roughly the same volume of air per revolution as a 1000cc four-stroke piston engine.
2. #1 is why racing series such as MotoGP eight or nine years ago (and all of the racing classes I've ever heard of) pitted two-strokes against four-strokes of roughly twice the displacement.
3. A 500cc Rotary "pumps" roughly the same volume of air per revolution as a 333cc four-stroke.
4. #1 + #2 + #3 mean a racing series should pit Rotaries against four-stroke pistons of roughly 2/3 the displacement. For example, the 7848cc 787B's engine should be competitive with four-stroke piston engines of about 5232cc.

There is a simple formula for Wankel displacement.

I'm interested in what that formula is, if you have any more info about it. How do they measure the stroke?

Thanks for the info about the FIA equivalency.


#96 MatsNorway

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Posted 15 February 2010 - 20:21


So you guys think a 500cc two-stroke is comparable to a 500cc four-stroke, then.


i think that should be the rule, ethically.

if you want to even the play field add eco rules about emissions and fuel consumption.

Or you think we should compare four-stroke piston engines to Rotaries revving 50% faster? Maybe in that comparison the Rotary will again come out looking pretty good?


the revving part i disagree to. its like only giving the diesels turbo, unfair.


Maybe we don't disagree about anything here and are just in another argument about terminology. Do we all agree that:
1. A 500cc two-stroke piston engine "pumps" roughly the same volume of air per revolution as a 1000cc four-stroke piston engine.


I agree, the thing to discuss is the competition basis and i think that rules shall be equal displacement and equal RPM and if you want it complicated add eco friendly rules - same amount of fuel at start ++ (future f1 perhaps)


#97 gruntguru

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Posted 16 February 2010 - 03:18

Maybe we don't disagree about anything here and are just in another argument about terminology. Do we all agree that:
1. A 500cc two-stroke piston engine "pumps" roughly the same volume of air per revolution as a 1000cc four-stroke piston engine.

Yes

2. #1 is why racing series such as MotoGP eight or nine years ago (and all of the racing classes I've ever heard of) pitted two-strokes against four-strokes of roughly twice the displacement..

Yes

3. A 500cc Rotary "pumps" roughly the same volume of air per revolution as a 333cc four-stroke..

A 500cc (Mazda rating) rotary pumps 500cc per revolution. A 500cc (real rating) rotary pumps 500/3 = 166cc per revolution. A 333 cc 4 stroke piston engine pumps 166cc per revolution. So Yes.

4. #1 + #2 + #3 mean a racing series should pit Rotaries against four-stroke pistons of roughly 2/3 the displacement. For example, the 7848cc 787B's engine should be competitive with four-stroke piston engines of about 5232cc..

Hmmm maybe!

I'm interested in what that formula is, if you have any more info about it. How do they measure the stroke?.

The stroke is the twice the eccentricity of the rotor. If you consider one "face" of the rotor as equivalent to a piston crown, the rectangular area of this face is the "piston area". The "stroke" is the difference between the maximum and minimum distance of this face from the crankshaft centreline.

From Wikipedia.Wankel engines can be classified by their geometric size in terms of radius (rotor center to tip distance, also the median stator radius) and depth (rotor thickness), and offset (crank throw, eccentricity, also 1/4 the difference between stator's major and minor axes). These metrics function similarly to the bore and stroke measurements of a piston engine. Displacement is 3√3radius¬∑offset¬∑depth, multiplied with the number of rotors. Nearly all Mazda production Wankel engines share a single rotor radius, 105 mm (4.1 in), with a 15 mm (0.6 in) crankshaft offset. The only engine to diverge from this formula was the rare 13A, which used a 120 mm (4.7 in) rotor radius and 17.5 mm (0.7 in) crankshaft offset.



#98 gruntguru

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Posted 16 February 2010 - 06:18

But this issue was brought up by comparing the hp/(liter by this method) of the 787B to a 20-year-newer four-stroke piston and saying it's therefore poor and underpowered.


Errrrrm . . . . . 20 years ago F1 engines were producing 200 bhp/litre (1500 hp from a 787B)

Edited by gruntguru, 16 February 2010 - 06:28.


#99 MatsNorway

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Posted 26 April 2010 - 21:36

What the displacement is is pretty irrelevant if fuel is the main power limitation. Thats why it should be the leading rule setter. Fuel flow should limit peak power perhaps but only if it reaches 900-1000hp.

And that is why i like fuel limit. because you could race 2 stroke, 4 stroke, wankel and any other motor that run on fuel.

I forgot that when we talked about what turbo performance would be today.


And since the turbo is about to make comeback in 2013 (discussed in the race comment forum)
http://en.espnf1.com...tory/15389.html

i surely hope that they also limit wing sizes and mechanical grip. adding some extra power and you have a spectaular race car.

Look how he fights the car and you can also see the fantastic acceleration.

This one is good to.
http://www.youtube.c...feature=related

Edited by MatsNorway, 26 April 2010 - 21:45.


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#100 desmo

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Posted 26 April 2010 - 23:01

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The best solution is arbitrarily telling everyone else what the best solution must be? These people are I'm sure very good at taking and giving direction and doing their jobs, but thinking cogently is obviously not their forte.