rotary engines: advantages
01-08-2008, 01:41 AM
#27
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lol.
OK i think this is the pendulum for the 'wankel'.
The ability to run Hydrogen fuel on the fly. If storage and efficiency can be doubled, then this will lead the way for city driving. Realistically, you don't need 240hp in heavy city areas.
OK i think this is the pendulum for the 'wankel'.
The ability to run Hydrogen fuel on the fly. If storage and efficiency can be doubled, then this will lead the way for city driving. Realistically, you don't need 240hp in heavy city areas.
01-08-2008, 01:57 AM
#28
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OPEC loves it. Advantage OPEC. Can you imagine OPEC having a circle jerk right now if the world was running on rotaries? Then again, its development would be much further along.
01-08-2008, 02:08 AM
#30
is adjusting valve lash
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^^oh no! MM's gonna tell him the truth now. he's gonna tell him our cars DO have valves.
don't do it, he'll probably kill himself if he's never had a piston car before...
don't do it, he'll probably kill himself if he's never had a piston car before...
Last edited by TrochoidMagic; 01-08-2008 at 02:11 AM.
01-08-2008, 02:33 AM
#33
is adjusting valve lash
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awww.... don't rotor heads hate that dreaded word, valves?its like using pistons, con-rods, crank bearings, camshafts, lifters, piston rings, springs all in one sentence.
01-08-2008, 02:47 AM
#35
I'll tell you what I like about rotaries - no crappy mechanical noises like tappet or cam chain rattles . I really hate those noises
What I like about some piston motors : They can be visual works of art - take a look at a bliged out EVO or s2000 motor - sexy . Then have a look at a renesis - real hard to get it to look anything at all - mainly because it is hidden by rubber hoses and plastic manifolds
What I like about some piston motors : They can be visual works of art - take a look at a bliged out EVO or s2000 motor - sexy . Then have a look at a renesis - real hard to get it to look anything at all - mainly because it is hidden by rubber hoses and plastic manifolds
Last edited by Brettus; 01-08-2008 at 02:53 AM.
01-08-2008, 02:57 AM
#36
The only way to make a rotary pretty is to strip it naked and strap a giant turbo on it.
The keg is just not something to look at and all the ancillaries are not aesthetically pleasing.
I do agree on the noises. I find myself listening for the faint "swish" of the side seals when the motor is cold.
The motor is so inherently quiet, that the mild tapping of the evap solenoid sounds like a cattle stampede by comparison.
The keg is just not something to look at and all the ancillaries are not aesthetically pleasing.
I do agree on the noises. I find myself listening for the faint "swish" of the side seals when the motor is cold.
The motor is so inherently quiet, that the mild tapping of the evap solenoid sounds like a cattle stampede by comparison.
01-08-2008, 03:20 AM
#37
01-08-2008, 06:22 AM
#40
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the rotary is alot smoother than conventional piston engines cause of the less moving parts in the engine.
plus our 1.3L can compete w/ some decent sized V6's but weight a whole lot less and still produce the same amount of HP
plus our 1.3L can compete w/ some decent sized V6's but weight a whole lot less and still produce the same amount of HP
01-08-2008, 04:58 PM
#43
Registered
If you include every seal in a 2 rotor engine, the total number of parts are as follows. Keep in mind I'm only referring to moving parts. Stationary gears and bearings don't move.
apex seals: 6
apex seal springs: 12
corner seals: 12
corner seal springs: 12
side seals: 12
side seal springs: 12
oil seals: 8
oil seal springs: 8
cutoff seals: 4
cutoff seal springs: 4
rotors: 2
eccentric shaft: 1
That's 93 parts. Major moving parts however only equals 3 as seals are not considered major moving parts.
In a 1 cylinder engine by comparison, not counting seals you could have:
piston: 1
connecting rod: 1
crankshaft: 1
valves: 2-4 (and even up to 5 on rare occasions)
valve springs: 2-4 (5)
camshaft: 1-2
That alone is anywhere from 8-13 major moving parts assuming it's an overhead cam engine per cylinder. That's not including any seals, rings, wrist pins, etc. A non overhead valve engine would add pushrods and rocker arms at a minimum.
The rotary always has fewer moving parts than a piston engine. There's no way around this. You can count every single little part inside the rotary and add them up but at the end of the day the number of major moving parts that exert any appreciable force from mass on anything only equals 3. 2 rotors and 1 eccentric shaft. This is a huge rotary advantage. Fewer parts means simplicity and that's a wonderful thing.
Another advantage is power per size of package. The rotary is very compact. A manifold doesn't have to be big and bulky. It can be very simple an compact which is why it's a great small airplane engine.
The fact that it is physically small also means that it's center of gravity is over a very small total area in both horizontal and vertical directions. That's an advantage for many reasons from packaging to handling.
No the rotary isn't a perfect engine. There isn't any one engine that can claim this title. For it's size it's far more impressive than many very popular engines though. Even the great LS1 is nothing special. It doesn't really produce an impressive amount of power for it's displacement and can't be held at high rpms for extensive amounts of time at high loads. If you don't believe me then go look up small airplane conversions that have used these engines. They ALL fail spectaularly. The only reason that engine does what it does is due to it's size. They kept weight relatively low by building it out of aluminum and it's plentiful. Americans go crazy over V8's. You could build a crap one and it would sell. Ford does it all day everyday.
The point of this is to show that although the rotary has it's negatives, you really need to appreciate and respect what it does for what it is. It's simplicity and small size are impressive compared to many others. If it were all aluminum, there wouldn't be another engine of it's weight out there that could produce the same amount of power. It's not perfect but it's got advantages. Those that think it doesn't really have no clue and should best be left alone to grow their mullets and build their overly large and heavy engines.
apex seals: 6
apex seal springs: 12
corner seals: 12
corner seal springs: 12
side seals: 12
side seal springs: 12
oil seals: 8
oil seal springs: 8
cutoff seals: 4
cutoff seal springs: 4
rotors: 2
eccentric shaft: 1
That's 93 parts. Major moving parts however only equals 3 as seals are not considered major moving parts.
In a 1 cylinder engine by comparison, not counting seals you could have:
piston: 1
connecting rod: 1
crankshaft: 1
valves: 2-4 (and even up to 5 on rare occasions)
valve springs: 2-4 (5)
camshaft: 1-2
That alone is anywhere from 8-13 major moving parts assuming it's an overhead cam engine per cylinder. That's not including any seals, rings, wrist pins, etc. A non overhead valve engine would add pushrods and rocker arms at a minimum.
The rotary always has fewer moving parts than a piston engine. There's no way around this. You can count every single little part inside the rotary and add them up but at the end of the day the number of major moving parts that exert any appreciable force from mass on anything only equals 3. 2 rotors and 1 eccentric shaft. This is a huge rotary advantage. Fewer parts means simplicity and that's a wonderful thing.
Another advantage is power per size of package. The rotary is very compact. A manifold doesn't have to be big and bulky. It can be very simple an compact which is why it's a great small airplane engine.
The fact that it is physically small also means that it's center of gravity is over a very small total area in both horizontal and vertical directions. That's an advantage for many reasons from packaging to handling.
No the rotary isn't a perfect engine. There isn't any one engine that can claim this title. For it's size it's far more impressive than many very popular engines though. Even the great LS1 is nothing special. It doesn't really produce an impressive amount of power for it's displacement and can't be held at high rpms for extensive amounts of time at high loads. If you don't believe me then go look up small airplane conversions that have used these engines. They ALL fail spectaularly. The only reason that engine does what it does is due to it's size. They kept weight relatively low by building it out of aluminum and it's plentiful. Americans go crazy over V8's. You could build a crap one and it would sell. Ford does it all day everyday.
The point of this is to show that although the rotary has it's negatives, you really need to appreciate and respect what it does for what it is. It's simplicity and small size are impressive compared to many others. If it were all aluminum, there wouldn't be another engine of it's weight out there that could produce the same amount of power. It's not perfect but it's got advantages. Those that think it doesn't really have no clue and should best be left alone to grow their mullets and build their overly large and heavy engines.
01-08-2008, 11:44 PM
#48
Not sure if you can count this. You obviously haven't been around sport bike engines, have you? Give a piston motor a decidedly over-square build (big bore, short stroke), fill it with strong, lightweight internals, and you have a recipe for a 17,500 rpm redline, which the current Yamaha YZF-R6 600cc in-line 4 cylinder has.
Honda also had a quad-carbed 600cc in-line 4 cylinder race motor back in the late 70's they stuffed in some of their Nighthawk's and other bikes for racing that revved to 23,000 rpm.
Miniature R/C cars that use 2-stroke nitro-burning single cylinder, air-cooled .12-.21cc motors can rev to over 60,000 rpm as well, and idle at over 6,000 rpm!
Beyond all that, surprised no one mentioned this Pro; It's unique!
Honda also had a quad-carbed 600cc in-line 4 cylinder race motor back in the late 70's they stuffed in some of their Nighthawk's and other bikes for racing that revved to 23,000 rpm.
Miniature R/C cars that use 2-stroke nitro-burning single cylinder, air-cooled .12-.21cc motors can rev to over 60,000 rpm as well, and idle at over 6,000 rpm!
Beyond all that, surprised no one mentioned this Pro; It's unique!
01-08-2008, 11:54 PM
#49
Not sure if you can count this. You obviously haven't been around sport bike engines, have you? Give a piston motor a decidedly over-square build (big bore, short stroke), fill it with strong, lightweight internals, and you have a recipe for a 17,500 rpm redline, which the current Yamaha YZF-R6 600cc in-line 4 cylinder has.
Honda also had a quad-carbed 600cc in-line 4 cylinder race motor back in the late 70's they stuffed in some of their Nighthawk's and other bikes for racing that revved to 23,000 rpm.
Miniature R/C cars that use 2-stroke nitro-burning single cylinder, air-cooled .12-.21cc motors can rev to over 60,000 rpm as well, and idle at over 6,000 rpm!
Beyond all that, surprised no one mentioned this Pro; It's unique!
Honda also had a quad-carbed 600cc in-line 4 cylinder race motor back in the late 70's they stuffed in some of their Nighthawk's and other bikes for racing that revved to 23,000 rpm.
Miniature R/C cars that use 2-stroke nitro-burning single cylinder, air-cooled .12-.21cc motors can rev to over 60,000 rpm as well, and idle at over 6,000 rpm!
Beyond all that, surprised no one mentioned this Pro; It's unique!
I know R/C cars's engine go crazy on RPM, you think I've never play with HPI before?
I still have them and that little bastard runs fast (it run faster than my 8, in the first 1-2 seconds LOL)but when you talking about the same purpose theres not much competition.
01-09-2008, 01:17 PM
#50
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the biggest pro for the rotary isn't for cars, it's for airplanes:
reliability thru simplicity: it won't fail catasthophically because it's perfectly balanced. Even if it blows a seal or it misfires or the oil runs out, if you have a problem the engine will still make some form of power for an amount of time, enough to get you that little extra distance and quite possibly save your life.
A piston engine that throws connecting rod or something of the like will literally tear itself to pieces, immediately lose all power and depending on the damage even eject pistons or other parts out the side of the aircraft.
it's also quieter and the frontal profile is much much smaller that lets you design more aerodynamically.
but there are still tradeoffs, you need to water cool it and you need a gearbox to get the engine revs down to normal prop operating speeds so the weight advantage doesn't exist.
reliability thru simplicity: it won't fail catasthophically because it's perfectly balanced. Even if it blows a seal or it misfires or the oil runs out, if you have a problem the engine will still make some form of power for an amount of time, enough to get you that little extra distance and quite possibly save your life.
A piston engine that throws connecting rod or something of the like will literally tear itself to pieces, immediately lose all power and depending on the damage even eject pistons or other parts out the side of the aircraft.
it's also quieter and the frontal profile is much much smaller that lets you design more aerodynamically.
but there are still tradeoffs, you need to water cool it and you need a gearbox to get the engine revs down to normal prop operating speeds so the weight advantage doesn't exist.