Why Do Rotaries Suck?

[DRD-00F]

You know what the funny thing is about the writing in bold. That's exactly what it is. Because it's only one part of the engine that's different to the rest. And you want to total it into some aggregated displacement? When total displacement figures assume that displacement is equally shared amongst chambers?

Even if I'm wrong about my averaging, your totalling assumes that the 4 litre is evenly divided amongst combustion chambers...it's not the case. If one chamber has different displacement to the rest then you need to state so...and only for that cycle will it be a 1.4 litre engine...for the other cycles it will be a 1.3 litre engine. This is such a bad hypothetical example anyway, because balanced engines don't work this way.

I don't understand how you think that compressing air in 2 different ways is so similar that it's comparable? What's your point? For my argument the key words are "different ways". How many spark plugs there are does mean something. If you have 0 spark plugs in an engine it won't run, if you have 3 spark plugs in only 3 chambers of a 6 cylinder engine, it will run as a 3 cylinder engine. If you have spark plugs in all cylinders, it will run as a 6 cylinder engine. How can you say that number of spark plugs and where they are located does not affect it? Nothing wrong with looking at these finer details mate, this is afterall, how an engine works...it's not a simple machine, they are complex.

So I suppose my 2.5L engine should change what it is advertised as depending on what point the pistons are at? Well if that's the case, it will NEVER be 2.5L

Total displacement doesn't assume anything. It's how much air moves through the engine in total. That's what total means.

Again, not assuming anything. If an engine moves 4L of air, then it's a 4L engine. Why would i have to state if one chamber had different displacement? What if I didn't know, WHAT IF I JUST WANTED TO ASSUME MY CUSTOMERS ALREADY KNEW THIS??? I though that's what you were all about... assumptions. I still honestly believe your idea of a 'cycle' is inherrently flawed. A cycle can involve a smaller cycle, but for a true cycle, it should not differ from the previous, or the next cycle, which yours does. My cycle incorporates your 3 cycles that you mentioned. So while I've done one cycle, and could do a billion more that are EXACTLY THE SAME, you've done 3, all of which are different. That's hardly a cycle.

For simplicities sake, I was focussing on one chamber. As long as it has one, it could have 5 more and make little to no difference. Again, just talking about a single chamber... stay with me.

And to be honest, these are pretty simple machines. Whatever screen you're looking at RIGHT NOW is a much more complicated machine then these engines.

[GT-R32]

here is a better example

you can keep your 1.3 Rotor

we will change all Piston engines to the following

2 Stroke 2 litre = 1 litre

4 stroke 2 litre = 0.5 litres

6 stroke 2 litre = 0.3 litres

you see piston engines per cyclinder uses less than a rotor......!

Incorrect. That would be:

2 stroke 2 litre = 2L

4 stroke 2 litre = 1L

6 stroke 2 litre = 0.67L

[Birds]

Nah you've lost me already mate, you've gone off on some sort of tangent I can't fathom...when did I ever say Mazda assumed their customers knew stuff? I'm pretty sure like most manufacturers, if anything they assume their customers don't know shit. But they don't write the figures down for all those customers, they write them down for the customers who do know.

Engine? Simple machine? Go and invent an internal combustion engine that doesn't use pistons and see how far you get mate. You guys are wagering your logic against some of the best engineers in the world...nice.

[DRD-00F]

I apologise I missed the part of your example where all 100 chambers had spark plugs in all of them...so if they are hypothetically igniting at the same time then yes it's a 130L engine. Remember, I said if hypothetically a 13B rotary could ignite all chambers at once then what would you call the engine? 3.9 litres or 11.7 litres?

Tell me, and here's stretching the limits of hypothetical...but if a rotor had 1000 faces and just as many chambers but only spark plugs in one of those chambers...would it be a 1300 litre engine or a 1.3 litre? Pretty horrible performance for a 1300 litre engine LOL, given it can only ignite ONE CHAMBER AT A TIME.

That's fantastic, your example has actually further proved my point that a rotary only has a valid 1.3 litres of combustible displacement and it's own cycle.

Yes, but it ignites that chamber 1000 times per cycle. so 1300L it is!

Which I didn't take into account on my 130L rotary aircraft engine hypothesis so that would be like... carry the one... 13 000Ls

big engines... I f**ked up.

[Birds]

Can't we just settle this over a game of CSS? Shotties in cs_office?

[fuzzy_scuz]

Incorrect. That would be:

2 stroke 2 litre = 2L

4 stroke 2 litre = 1L

6 stroke 2 litre = 0.67L

No it isn't by mazda's logic my numbers are correct.......

You see Mazda is WRONG!

[Smity42]

Can't we just settle this over a game of CSS? Shotties in cs_office?

lol

[DRD-00F]

lol, love to!

I'm taking a break from this thread over the long weekend... cbf this

[DRD-00F]

Hey birds, just one more thing before the weekend...

If you were to do a compression test on a rotary, how many degrees would you turn the E shaft? If it's only got 2 ignition chambers it should only need 360 degrees yeah? That's 1 cycle yeah?? Cause a compression test only requires one cycle of the engine, any more and you're repeating yourself... and we all hate that right?

[madbung]

Weeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeeee

Look a dog with a fluffy tail..

[scathing]

If you were to do a compression test on a rotary

I'm half-expecting the response to be, "You can't do compression tests on rotaries because they're so different. They don't compress air, they rotarise it."

[bigslick]

This has just gotten ridiculous.

*walks out door*

[jase-r34]

I'm half-expecting the response to be, "You can't do compression tests on rotaries because they're so different. They don't compress air, they rotarise it."

I dead set near wet myself reading that LOL

[ylwgtr2]

[ylwgtr2]

AYE CARUMBA!

Edited October 2, 2009 by ylwgtr2

[GTR-32U]

Fk the Rotaries and BS combustion cycles ....^ This is where its at

Edited October 2, 2009 by GTR-32U

[Birds]

Hey birds, just one more thing before the weekend...

If you were to do a compression test on a rotary, how many degrees would you turn the E shaft? If it's only got 2 ignition chambers it should only need 360 degrees yeah? That's 1 cycle yeah?? Cause a compression test only requires one cycle of the engine, any more and you're repeating yourself... and we all hate that right?

And my last post before my weekend celebrations...damn Sydneyites getting Monday off...

Dry or wet test?

I don't know how to compression test a rotary but I assume it is done via the spark plug recess where compression is at its peak...in which case you would need to turn the eccentric shaft 3 times for a total of 1080 degrees because due to there only being one combustion chamber in the rotor housing, you can only measure the compression of each rotor face using this chamber. Therefore each face of the rotor must face this one combustion chamber at some point. Were it a 3.9 litre engine I'm sure you could check compression from each individual chamber via each chamber's spark plug recess

Or is that two turns of the eccentric shaft...because this would be enough to check all apex seals using only two faces of the rotor, as is a unique ability of this engine?

It's never going to end mate; for every answer you guys throw towards us we have something to answer it back and vice versa. And the truth is, everyone to an extent is making valid points here...which is why this argument has continued on for so long. Believe what you guys want, I'm sticking with my theories about this engine and I'll respectfully agree to disagree with you on the basis that everyone here has demonstrated a nice in-depth analysis on the workings of these engines...without coming to universally agreeable conclusions. I myself am pretty happy to have come this far given I have no formal training/education in mechanics or physics and 5 years ago I couldn't point you to a throttle body to save myself (though I did know internal combustion from an early age - thank you nerdy computer games).

[GT-R32]

Hey birds, just one more thing before the weekend...

If you were to do a compression test on a rotary, how many degrees would you turn the E shaft? If it's only got 2 ignition chambers it should only need 360 degrees yeah? That's 1 cycle yeah?? Cause a compression test only requires one cycle of the engine, any more and you're repeating yourself... and we all hate that right?

1080 degrees as there are 6 pulses to measure. We all know that. I see what you did there.

Nice points with your combustion chamber comments Birds

[trance]

Just like to say thanks to whoever the hell brought this up at the gala ball last night.

[Birds]

IT WAS MEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEEE

I was severely drunk and I thought a V8 supercar driver's opinion could be valuable to the discussion. Dean Canto's response: NFI

Sorry guys it seemed like a good idea at the time LOL.