New Rotary Engine Maker
11-01-05, 12:51 PM
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New Rotary Engine Maker
Being a stickler for detail, as well as a fanatical researcher of details, I sent an e-mail to this outfit that makes “b” sized rotary engines. I was particularly amazed at how much they weigh. And that emissions are better than 13bs!
Subject : RE: Scalability and other questions
RotaMax Inc 419-694-3000 Ext 222
www.rotamax.net
From: Smilodon (I’m not showing y’all my e-mail address!)
Sent: Monday, October 31, 2005 4:39 PM
To: eric@thermofan.com
Subject: Scalability and other questions
My words are in black, his responses were written into my e-mail in blue, so I will put them up pretty well as he wrote them. As you can tell, I got a few of my facts wrong. Glad I asked him for more info.
Me: I was about to post some stuff on a forum about your motors, but I figured I better get my facts straight first. Ignorance is one thing, but a bold public display thereof is quite another.
E: I appreciate it, as posting incorrect information makes everyone's job a little tougher
Me: Since the induction is carried entirely in one end plate, This is not true the induction is carried thru the rotor and then enters through a bridge port in the side of the housing and a peripheral port in the rotor housing itself for far better consistency between rotors in any 3+rotor motor possibility, and no cramming air through narrow little ports that are both fighting for the space between rotors. The ports are pretty good size compared to stock Mazda ports. Future performance testing and potentially porting will tell the limits of the port design.
If the exhaust ports are on the opposite side of the rotor case, or, peripheral, The exhaust port is on the opposite side and is peripheral then this could lead to some nice breathing even if there is overlap,due to the cross-flow. All it needs is some multi-lobed eccentrics to make it the world's most affordable 26b, 33b, 39b, whatever. "b" referring only to the fact that it has 650cc per rotor, not to any design similarities with Mazda We do need a name for our engine other than single twin triple Etc.
But, I don't know the prices of the motors, and I wanted to get my facts straight first. I think your engines have limitless potential, based on what I know or think I know about them. And I think others should know about them too. Current pricing is 5K for a single and 7500 for a twin this is with carbs and CDI ignition. Prices will decrease as volume increases.
A) Are the rotor segments each self-contained, so that, truly, all you need is an eccentric shaft with more (and properly timed) eccentrics to make this engine into a multi-rotor monster? Yes although we would have to take a close look at cooling and maybe do a two segment cooling system in a four rotor as the heat could be too much and it would also decrease radiator size.
A)1) Supposing the ignitions for each segment are self-contained, does that mean that in a multi-rotor setup, the ignition would be timed from that segment of the motor, and not from a timing mark that is four rotors away on the front of the motor, where e-shaft torsional flex could throw timing off? Currently the plan is to time it off one end although the other end would be an option and only testing would validate how much flex there is if any. The rotary is pretty forgiving as far as timing is concerned.
B) Outside of the rotor shaft, what is the cost-per-rotor for the motor? Pricing is above although it is not quite linear. In the future with volume it will probably be a rotor times X equals price.
C) Would it be possible to upgrade an existing motor at a later date by putting on another rotor segment? (and new e-shaft) How about modular e-shafts that bolt together? With enough bolt holes to handle 2,3,4,6 rotors? (five would need way too many holes extra. 2,3,4,6 only need 12 holes total, evenly spaced, for 180 degree firing, 120 degree firing, 90 degree fring, or 60 degree firing) We would like to do a three and four rotor design in tandem, the three and four rotor eccentrics are laid out pretty well and I also have a PDF of a current four rotor shaft being built. We do all of opr own machining and testing here, and I do have a couple 4x48” solid 8620 that would make some nice shafts.
D) will electronic fuel injection work for this setup? Do you know any that are available that are, or can be scaled up to 2-3-4 rotors? We have our own ECU that has been designed and built for us to go up to 4 rotors.
E) Will it fit onto existing 13b motor/transmission mounts? No but I am sure someone and maybe us will make a bracket for easy transplant into a mazda.
F) In fact, is it a straight drop-in for a 13b?See above
G) Does it weigh similar to a 13b on a per-rotor basis? Is it lighter than a 20b on a per-rotor basis? The engine is considerably lighter our twin is 153Lbs. A 13B is 330 Approx. Our engine is on a weight loss program and we expect to be at the 125 to 130LBs in the twin.
H) What advantages does it have over stock 13b engines? Light, very versatile for mounting in all kinds of applications. It has a little brother the single and will have two big brothers a triple and a quad rotor. Then along will come the 150cc (wow) what a nice little engine.
I) Can I add a third spark plug to each rotor like the 26b? No you would protrude thru water jackets the engine is currently a single plug. We have discussed multi plug and multi spark options.
J) What are the practical limits to the number of cases I could put together?4
K) Can it handle being turbocharged? How much HP per rotor could be expected before having to upgrade it, whether cooling, oil supply, oil cooling, apex seals, whatever. We are excited to get a supercharger on the engine with 15LBs of boost this should double the HP in theory so actually an 80% gain would be obtainable so we see a potential to have a single rotor at 160HP/Rotor so if you do the math on a twin, triple, quad. Mazda guys brag these type engine can handle 30LBs of boost.
L) Are there lightweight rotors available for those who have an irrational love of high revs? (note: I didn't say so, but "those" includes ME!) Are there different compression rotors available for those who want to use roots, screw, or centrifugal blowers and/or nitrous oxide, and/or turbos? Or for those who want to run it at extremely low revs? We do not have light weight rotors “at this time” we can design and machine different compression ratios.
M) To increase the ratio of volume to surface area of the rotor/case/side plates, how about fatter rotors? Same diameter, but wider. This might require peripheral intake ports, or twin side ports on fatter side plates, but might it yield better heat efficiency due to there being, say one and a half times as much chamber volume per unit of chamber average surface area? Or is it better to maintain the present proportions and get your volume-to-surface-area boost by making the whole thing bigger in every direction? Geometry was figured out by yamamoto and it is kind of a rule of thumb for a lot of reasons based on 100s of thousands of testing hours at Mazda.
N) How about a one-motor racing series with Rotamax engines? Like IROC, no mods could be done to the motor or car, seat time is cheap, engines are exceedingly reliable and inexpensive per unit of powerXhours. We are looking forward to it, and believe we could offer a very reliable box engine class.
O) The aftermarket is full of cylinder heads, blocks, pistons, etc. Why not an aftermarket rotary that will be far better than the originals? Especially if it passes emissions with flying colors as it stands, it could be an EPA pre-approved modification for all fifty states. It is an emission incinerator. Tests will show how much.
P) Since the 20b is the exotic inhabitant of many rotorheads' dreams, (read: MINE) what if Rotamax had them for similar or less price, ready to run, than the 20bs that are now imported in quantities that are limited like bootleg liquor? We look forward to this; also as we think there would be a real market for three and four rotor engines. And I would like to have my own four rotor RX8.
Subject : RE: Scalability and other questions
RotaMax Inc 419-694-3000 Ext 222
www.rotamax.net
From: Smilodon (I’m not showing y’all my e-mail address!)
Sent: Monday, October 31, 2005 4:39 PM
To: eric@thermofan.com
Subject: Scalability and other questions
My words are in black, his responses were written into my e-mail in blue, so I will put them up pretty well as he wrote them. As you can tell, I got a few of my facts wrong. Glad I asked him for more info.
Me: I was about to post some stuff on a forum about your motors, but I figured I better get my facts straight first. Ignorance is one thing, but a bold public display thereof is quite another.
E: I appreciate it, as posting incorrect information makes everyone's job a little tougher
Me: Since the induction is carried entirely in one end plate, This is not true the induction is carried thru the rotor and then enters through a bridge port in the side of the housing and a peripheral port in the rotor housing itself for far better consistency between rotors in any 3+rotor motor possibility, and no cramming air through narrow little ports that are both fighting for the space between rotors. The ports are pretty good size compared to stock Mazda ports. Future performance testing and potentially porting will tell the limits of the port design.
If the exhaust ports are on the opposite side of the rotor case, or, peripheral, The exhaust port is on the opposite side and is peripheral then this could lead to some nice breathing even if there is overlap,due to the cross-flow. All it needs is some multi-lobed eccentrics to make it the world's most affordable 26b, 33b, 39b, whatever. "b" referring only to the fact that it has 650cc per rotor, not to any design similarities with Mazda We do need a name for our engine other than single twin triple Etc.
But, I don't know the prices of the motors, and I wanted to get my facts straight first. I think your engines have limitless potential, based on what I know or think I know about them. And I think others should know about them too. Current pricing is 5K for a single and 7500 for a twin this is with carbs and CDI ignition. Prices will decrease as volume increases.
A) Are the rotor segments each self-contained, so that, truly, all you need is an eccentric shaft with more (and properly timed) eccentrics to make this engine into a multi-rotor monster? Yes although we would have to take a close look at cooling and maybe do a two segment cooling system in a four rotor as the heat could be too much and it would also decrease radiator size.
A)1) Supposing the ignitions for each segment are self-contained, does that mean that in a multi-rotor setup, the ignition would be timed from that segment of the motor, and not from a timing mark that is four rotors away on the front of the motor, where e-shaft torsional flex could throw timing off? Currently the plan is to time it off one end although the other end would be an option and only testing would validate how much flex there is if any. The rotary is pretty forgiving as far as timing is concerned.
B) Outside of the rotor shaft, what is the cost-per-rotor for the motor? Pricing is above although it is not quite linear. In the future with volume it will probably be a rotor times X equals price.
C) Would it be possible to upgrade an existing motor at a later date by putting on another rotor segment? (and new e-shaft) How about modular e-shafts that bolt together? With enough bolt holes to handle 2,3,4,6 rotors? (five would need way too many holes extra. 2,3,4,6 only need 12 holes total, evenly spaced, for 180 degree firing, 120 degree firing, 90 degree fring, or 60 degree firing) We would like to do a three and four rotor design in tandem, the three and four rotor eccentrics are laid out pretty well and I also have a PDF of a current four rotor shaft being built. We do all of opr own machining and testing here, and I do have a couple 4x48” solid 8620 that would make some nice shafts.
D) will electronic fuel injection work for this setup? Do you know any that are available that are, or can be scaled up to 2-3-4 rotors? We have our own ECU that has been designed and built for us to go up to 4 rotors.
E) Will it fit onto existing 13b motor/transmission mounts? No but I am sure someone and maybe us will make a bracket for easy transplant into a mazda.
F) In fact, is it a straight drop-in for a 13b?See above
G) Does it weigh similar to a 13b on a per-rotor basis? Is it lighter than a 20b on a per-rotor basis? The engine is considerably lighter our twin is 153Lbs. A 13B is 330 Approx. Our engine is on a weight loss program and we expect to be at the 125 to 130LBs in the twin.
H) What advantages does it have over stock 13b engines? Light, very versatile for mounting in all kinds of applications. It has a little brother the single and will have two big brothers a triple and a quad rotor. Then along will come the 150cc (wow) what a nice little engine.
I) Can I add a third spark plug to each rotor like the 26b? No you would protrude thru water jackets the engine is currently a single plug. We have discussed multi plug and multi spark options.
J) What are the practical limits to the number of cases I could put together?4
K) Can it handle being turbocharged? How much HP per rotor could be expected before having to upgrade it, whether cooling, oil supply, oil cooling, apex seals, whatever. We are excited to get a supercharger on the engine with 15LBs of boost this should double the HP in theory so actually an 80% gain would be obtainable so we see a potential to have a single rotor at 160HP/Rotor so if you do the math on a twin, triple, quad. Mazda guys brag these type engine can handle 30LBs of boost.
L) Are there lightweight rotors available for those who have an irrational love of high revs? (note: I didn't say so, but "those" includes ME!) Are there different compression rotors available for those who want to use roots, screw, or centrifugal blowers and/or nitrous oxide, and/or turbos? Or for those who want to run it at extremely low revs? We do not have light weight rotors “at this time” we can design and machine different compression ratios.
M) To increase the ratio of volume to surface area of the rotor/case/side plates, how about fatter rotors? Same diameter, but wider. This might require peripheral intake ports, or twin side ports on fatter side plates, but might it yield better heat efficiency due to there being, say one and a half times as much chamber volume per unit of chamber average surface area? Or is it better to maintain the present proportions and get your volume-to-surface-area boost by making the whole thing bigger in every direction? Geometry was figured out by yamamoto and it is kind of a rule of thumb for a lot of reasons based on 100s of thousands of testing hours at Mazda.
N) How about a one-motor racing series with Rotamax engines? Like IROC, no mods could be done to the motor or car, seat time is cheap, engines are exceedingly reliable and inexpensive per unit of powerXhours. We are looking forward to it, and believe we could offer a very reliable box engine class.
O) The aftermarket is full of cylinder heads, blocks, pistons, etc. Why not an aftermarket rotary that will be far better than the originals? Especially if it passes emissions with flying colors as it stands, it could be an EPA pre-approved modification for all fifty states. It is an emission incinerator. Tests will show how much.
P) Since the 20b is the exotic inhabitant of many rotorheads' dreams, (read: MINE) what if Rotamax had them for similar or less price, ready to run, than the 20bs that are now imported in quantities that are limited like bootleg liquor? We look forward to this; also as we think there would be a real market for three and four rotor engines. And I would like to have my own four rotor RX8.
Last edited by Smilodon; 11-01-05 at 01:07 PM.
11-01-05, 07:59 PM
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Not that this is relevant, but this is my thread, so what the heck. Hey, according to my calculations, A rotary, at 7000 rpm will ingest 321 cfm.
321 cfm is not much air.
So, 130 hp from 321 cfm?
So, roughly, if I wanted 500 hp, assuming no greater or less efficiency, then I would want 1234 cfm.
Hoooo boy. That's a lot of cfm.
In a 3 inch tube, at 2.0 bar of boost (about 28 psi) that much net intake air would be flowing at approximately 142 mph.
Thus, 250 hp=71 mph.
130hp = 36.92 mph.
So, all the drastic right angle turns and tight spaces that most turbo air has to weasel through before making it through the intercooler to the engine must be seriously robbing power.
I have noticed that internal aerodynamics of the intake and exhaust systems seem to be completely ignored by most people. Smooth turns, large pipes, and more internally aerodynamically efficient intercoolers could unlock more usable power for any given level of boost.
Granted, most people know bigger ports mean better flow. But, to have a 3" exhaust on a 300 hp engine, and the same 3" exhaust on a 500 hp engine? And how about that drastic right angle turn that air has to make when it enters an intercooler than has to dive down into the cross-flowing fins of the aftercooler?
I know packaging and profit margins are important. But the laws of physics don't bow to our wallets.
Since energy required to make things or fluids change direction varies as the square of the speed of said change, the 500 hp turbo motor would be wasting 2.77 times the energy to move air from intake to rotor case than the same engine producing 300 hp.
I don't know why I brought this up, but, come to think of it, it seems you could extract more power from a multi-rotor engine more easily and with more efficiency than you could a two-rotor engine. And with less stress on the motor.
Now, to those of you who would say this is obvious, I reply that the best part of all that is that since stress seems to increase as the square of the power output per unit of motor size, it becomes even more evident why multiple rotors could last MUCH longer for a given power output than two rotors.
Considering all the huge wodges of cash that people dump into their cars to eke out a couple hundred or so hp, multi-rotor cost effectiveness shines even brighter. Especially when a four-rotor as described in my e-mail reply above would weigh close to what a stock two-rotor weighs.
Hoo hah!
321 cfm is not much air.
So, 130 hp from 321 cfm?
So, roughly, if I wanted 500 hp, assuming no greater or less efficiency, then I would want 1234 cfm.
Hoooo boy. That's a lot of cfm.
In a 3 inch tube, at 2.0 bar of boost (about 28 psi) that much net intake air would be flowing at approximately 142 mph.
Thus, 250 hp=71 mph.
130hp = 36.92 mph.
So, all the drastic right angle turns and tight spaces that most turbo air has to weasel through before making it through the intercooler to the engine must be seriously robbing power.
I have noticed that internal aerodynamics of the intake and exhaust systems seem to be completely ignored by most people. Smooth turns, large pipes, and more internally aerodynamically efficient intercoolers could unlock more usable power for any given level of boost.
Granted, most people know bigger ports mean better flow. But, to have a 3" exhaust on a 300 hp engine, and the same 3" exhaust on a 500 hp engine? And how about that drastic right angle turn that air has to make when it enters an intercooler than has to dive down into the cross-flowing fins of the aftercooler?
I know packaging and profit margins are important. But the laws of physics don't bow to our wallets.
Since energy required to make things or fluids change direction varies as the square of the speed of said change, the 500 hp turbo motor would be wasting 2.77 times the energy to move air from intake to rotor case than the same engine producing 300 hp.
I don't know why I brought this up, but, come to think of it, it seems you could extract more power from a multi-rotor engine more easily and with more efficiency than you could a two-rotor engine. And with less stress on the motor.
Now, to those of you who would say this is obvious, I reply that the best part of all that is that since stress seems to increase as the square of the power output per unit of motor size, it becomes even more evident why multiple rotors could last MUCH longer for a given power output than two rotors.
Considering all the huge wodges of cash that people dump into their cars to eke out a couple hundred or so hp, multi-rotor cost effectiveness shines even brighter. Especially when a four-rotor as described in my e-mail reply above would weigh close to what a stock two-rotor weighs.
Hoo hah!
11-02-05, 06:23 AM
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Originally Posted by Smilodon
Being a stickler for detail, as well as a fanatical researcher of details, I sent an e-mail to this outfit that makes “b” sized rotary engines. I was particularly amazed at how much they weigh. And that emissions are better than 13bs!
Subject : RE: Scalability and other questions
RotaMax Inc 419-694-3000 Ext 222
www.rotamax.net
From: Smilodon (I’m not showing y’all my e-mail address!)
Sent: Monday, October 31, 2005 4:39 PM
To: eric@thermofan.com
Subject: Scalability and other questions
My words are in black, his responses were written into my e-mail in blue, so I will put them up pretty well as he wrote them. As you can tell, I got a few of my facts wrong. Glad I asked him for more info.
Me: I was about to post some stuff on a forum about your motors, but I figured I better get my facts straight first. Ignorance is one thing, but a bold public display thereof is quite another.
E: I appreciate it, as posting incorrect information makes everyone's job a little tougher
Me: Since the induction is carried entirely in one end plate, This is not true the induction is carried thru the rotor and then enters through a bridge port in the side of the housing and a peripheral port in the rotor housing itself for far better consistency between rotors in any 3+rotor motor possibility, and no cramming air through narrow little ports that are both fighting for the space between rotors. The ports are pretty good size compared to stock Mazda ports. Future performance testing and potentially porting will tell the limits of the port design.
If the exhaust ports are on the opposite side of the rotor case, or, peripheral, The exhaust port is on the opposite side and is peripheral then this could lead to some nice breathing even if there is overlap,due to the cross-flow. All it needs is some multi-lobed eccentrics to make it the world's most affordable 26b, 33b, 39b, whatever. "b" referring only to the fact that it has 650cc per rotor, not to any design similarities with Mazda We do need a name for our engine other than single twin triple Etc.
But, I don't know the prices of the motors, and I wanted to get my facts straight first. I think your engines have limitless potential, based on what I know or think I know about them. And I think others should know about them too. Current pricing is 5K for a single and 7500 for a twin this is with carbs and CDI ignition. Prices will decrease as volume increases.
A) Are the rotor segments each self-contained, so that, truly, all you need is an eccentric shaft with more (and properly timed) eccentrics to make this engine into a multi-rotor monster? Yes although we would have to take a close look at cooling and maybe do a two segment cooling system in a four rotor as the heat could be too much and it would also decrease radiator size.
A)1) Supposing the ignitions for each segment are self-contained, does that mean that in a multi-rotor setup, the ignition would be timed from that segment of the motor, and not from a timing mark that is four rotors away on the front of the motor, where e-shaft torsional flex could throw timing off? Currently the plan is to time it off one end although the other end would be an option and only testing would validate how much flex there is if any. The rotary is pretty forgiving as far as timing is concerned.
B) Outside of the rotor shaft, what is the cost-per-rotor for the motor? Pricing is above although it is not quite linear. In the future with volume it will probably be a rotor times X equals price.
C) Would it be possible to upgrade an existing motor at a later date by putting on another rotor segment? (and new e-shaft) How about modular e-shafts that bolt together? With enough bolt holes to handle 2,3,4,6 rotors? (five would need way too many holes extra. 2,3,4,6 only need 12 holes total, evenly spaced, for 180 degree firing, 120 degree firing, 90 degree fring, or 60 degree firing) We would like to do a three and four rotor design in tandem, the three and four rotor eccentrics are laid out pretty well and I also have a PDF of a current four rotor shaft being built. We do all of opr own machining and testing here, and I do have a couple 4x48” solid 8620 that would make some nice shafts.
D) will electronic fuel injection work for this setup? Do you know any that are available that are, or can be scaled up to 2-3-4 rotors? We have our own ECU that has been designed and built for us to go up to 4 rotors.
E) Will it fit onto existing 13b motor/transmission mounts? No but I am sure someone and maybe us will make a bracket for easy transplant into a mazda.
F) In fact, is it a straight drop-in for a 13b?See above
G) Does it weigh similar to a 13b on a per-rotor basis? Is it lighter than a 20b on a per-rotor basis? The engine is considerably lighter our twin is 153Lbs. A 13B is 330 Approx. Our engine is on a weight loss program and we expect to be at the 125 to 130LBs in the twin.
H) What advantages does it have over stock 13b engines? Light, very versatile for mounting in all kinds of applications. It has a little brother the single and will have two big brothers a triple and a quad rotor. Then along will come the 150cc (wow) what a nice little engine.
I) Can I add a third spark plug to each rotor like the 26b? No you would protrude thru water jackets the engine is currently a single plug. We have discussed multi plug and multi spark options.
J) What are the practical limits to the number of cases I could put together?4
K) Can it handle being turbocharged? How much HP per rotor could be expected before having to upgrade it, whether cooling, oil supply, oil cooling, apex seals, whatever. We are excited to get a supercharger on the engine with 15LBs of boost this should double the HP in theory so actually an 80% gain would be obtainable so we see a potential to have a single rotor at 160HP/Rotor so if you do the math on a twin, triple, quad. Mazda guys brag these type engine can handle 30LBs of boost.
L) Are there lightweight rotors available for those who have an irrational love of high revs? (note: I didn't say so, but "those" includes ME!) Are there different compression rotors available for those who want to use roots, screw, or centrifugal blowers and/or nitrous oxide, and/or turbos? Or for those who want to run it at extremely low revs? We do not have light weight rotors “at this time” we can design and machine different compression ratios.
M) To increase the ratio of volume to surface area of the rotor/case/side plates, how about fatter rotors? Same diameter, but wider. This might require peripheral intake ports, or twin side ports on fatter side plates, but might it yield better heat efficiency due to there being, say one and a half times as much chamber volume per unit of chamber average surface area? Or is it better to maintain the present proportions and get your volume-to-surface-area boost by making the whole thing bigger in every direction? Geometry was figured out by yamamoto and it is kind of a rule of thumb for a lot of reasons based on 100s of thousands of testing hours at Mazda.
N) How about a one-motor racing series with Rotamax engines? Like IROC, no mods could be done to the motor or car, seat time is cheap, engines are exceedingly reliable and inexpensive per unit of powerXhours. We are looking forward to it, and believe we could offer a very reliable box engine class.
O) The aftermarket is full of cylinder heads, blocks, pistons, etc. Why not an aftermarket rotary that will be far better than the originals? Especially if it passes emissions with flying colors as it stands, it could be an EPA pre-approved modification for all fifty states. It is an emission incinerator. Tests will show how much.
P) Since the 20b is the exotic inhabitant of many rotorheads' dreams, (read: MINE) what if Rotamax had them for similar or less price, ready to run, than the 20bs that are now imported in quantities that are limited like bootleg liquor? We look forward to this; also as we think there would be a real market for three and four rotor engines. And I would like to have my own four rotor RX8.
Subject : RE: Scalability and other questions
RotaMax Inc 419-694-3000 Ext 222
www.rotamax.net
From: Smilodon (I’m not showing y’all my e-mail address!)
Sent: Monday, October 31, 2005 4:39 PM
To: eric@thermofan.com
Subject: Scalability and other questions
My words are in black, his responses were written into my e-mail in blue, so I will put them up pretty well as he wrote them. As you can tell, I got a few of my facts wrong. Glad I asked him for more info.
Me: I was about to post some stuff on a forum about your motors, but I figured I better get my facts straight first. Ignorance is one thing, but a bold public display thereof is quite another.
E: I appreciate it, as posting incorrect information makes everyone's job a little tougher
Me: Since the induction is carried entirely in one end plate, This is not true the induction is carried thru the rotor and then enters through a bridge port in the side of the housing and a peripheral port in the rotor housing itself for far better consistency between rotors in any 3+rotor motor possibility, and no cramming air through narrow little ports that are both fighting for the space between rotors. The ports are pretty good size compared to stock Mazda ports. Future performance testing and potentially porting will tell the limits of the port design.
If the exhaust ports are on the opposite side of the rotor case, or, peripheral, The exhaust port is on the opposite side and is peripheral then this could lead to some nice breathing even if there is overlap,due to the cross-flow. All it needs is some multi-lobed eccentrics to make it the world's most affordable 26b, 33b, 39b, whatever. "b" referring only to the fact that it has 650cc per rotor, not to any design similarities with Mazda We do need a name for our engine other than single twin triple Etc.
But, I don't know the prices of the motors, and I wanted to get my facts straight first. I think your engines have limitless potential, based on what I know or think I know about them. And I think others should know about them too. Current pricing is 5K for a single and 7500 for a twin this is with carbs and CDI ignition. Prices will decrease as volume increases.
A) Are the rotor segments each self-contained, so that, truly, all you need is an eccentric shaft with more (and properly timed) eccentrics to make this engine into a multi-rotor monster? Yes although we would have to take a close look at cooling and maybe do a two segment cooling system in a four rotor as the heat could be too much and it would also decrease radiator size.
A)1) Supposing the ignitions for each segment are self-contained, does that mean that in a multi-rotor setup, the ignition would be timed from that segment of the motor, and not from a timing mark that is four rotors away on the front of the motor, where e-shaft torsional flex could throw timing off? Currently the plan is to time it off one end although the other end would be an option and only testing would validate how much flex there is if any. The rotary is pretty forgiving as far as timing is concerned.
B) Outside of the rotor shaft, what is the cost-per-rotor for the motor? Pricing is above although it is not quite linear. In the future with volume it will probably be a rotor times X equals price.
C) Would it be possible to upgrade an existing motor at a later date by putting on another rotor segment? (and new e-shaft) How about modular e-shafts that bolt together? With enough bolt holes to handle 2,3,4,6 rotors? (five would need way too many holes extra. 2,3,4,6 only need 12 holes total, evenly spaced, for 180 degree firing, 120 degree firing, 90 degree fring, or 60 degree firing) We would like to do a three and four rotor design in tandem, the three and four rotor eccentrics are laid out pretty well and I also have a PDF of a current four rotor shaft being built. We do all of opr own machining and testing here, and I do have a couple 4x48” solid 8620 that would make some nice shafts.
D) will electronic fuel injection work for this setup? Do you know any that are available that are, or can be scaled up to 2-3-4 rotors? We have our own ECU that has been designed and built for us to go up to 4 rotors.
E) Will it fit onto existing 13b motor/transmission mounts? No but I am sure someone and maybe us will make a bracket for easy transplant into a mazda.
F) In fact, is it a straight drop-in for a 13b?See above
G) Does it weigh similar to a 13b on a per-rotor basis? Is it lighter than a 20b on a per-rotor basis? The engine is considerably lighter our twin is 153Lbs. A 13B is 330 Approx. Our engine is on a weight loss program and we expect to be at the 125 to 130LBs in the twin.
H) What advantages does it have over stock 13b engines? Light, very versatile for mounting in all kinds of applications. It has a little brother the single and will have two big brothers a triple and a quad rotor. Then along will come the 150cc (wow) what a nice little engine.
I) Can I add a third spark plug to each rotor like the 26b? No you would protrude thru water jackets the engine is currently a single plug. We have discussed multi plug and multi spark options.
J) What are the practical limits to the number of cases I could put together?4
K) Can it handle being turbocharged? How much HP per rotor could be expected before having to upgrade it, whether cooling, oil supply, oil cooling, apex seals, whatever. We are excited to get a supercharger on the engine with 15LBs of boost this should double the HP in theory so actually an 80% gain would be obtainable so we see a potential to have a single rotor at 160HP/Rotor so if you do the math on a twin, triple, quad. Mazda guys brag these type engine can handle 30LBs of boost.
L) Are there lightweight rotors available for those who have an irrational love of high revs? (note: I didn't say so, but "those" includes ME!) Are there different compression rotors available for those who want to use roots, screw, or centrifugal blowers and/or nitrous oxide, and/or turbos? Or for those who want to run it at extremely low revs? We do not have light weight rotors “at this time” we can design and machine different compression ratios.
M) To increase the ratio of volume to surface area of the rotor/case/side plates, how about fatter rotors? Same diameter, but wider. This might require peripheral intake ports, or twin side ports on fatter side plates, but might it yield better heat efficiency due to there being, say one and a half times as much chamber volume per unit of chamber average surface area? Or is it better to maintain the present proportions and get your volume-to-surface-area boost by making the whole thing bigger in every direction? Geometry was figured out by yamamoto and it is kind of a rule of thumb for a lot of reasons based on 100s of thousands of testing hours at Mazda.
N) How about a one-motor racing series with Rotamax engines? Like IROC, no mods could be done to the motor or car, seat time is cheap, engines are exceedingly reliable and inexpensive per unit of powerXhours. We are looking forward to it, and believe we could offer a very reliable box engine class.
O) The aftermarket is full of cylinder heads, blocks, pistons, etc. Why not an aftermarket rotary that will be far better than the originals? Especially if it passes emissions with flying colors as it stands, it could be an EPA pre-approved modification for all fifty states. It is an emission incinerator. Tests will show how much.
P) Since the 20b is the exotic inhabitant of many rotorheads' dreams, (read: MINE) what if Rotamax had them for similar or less price, ready to run, than the 20bs that are now imported in quantities that are limited like bootleg liquor? We look forward to this; also as we think there would be a real market for three and four rotor engines. And I would like to have my own four rotor RX8.
We at RotaMax have not stated our emmissions yet, it would be incorrect to say that the engine has better emmissions than a 13B.
Eric Barger
RotaMax
11-02-05, 05:55 PM
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Originally Posted by Smilodon
Me: Since the induction is carried entirely in one end plate, This is not true the induction is carried thru the rotor and then enters through a bridge port in the side of the housing and a peripheral port in the rotor housing itself for far better consistency between rotors in any 3+rotor motor possibility, and no cramming air through narrow little ports that are both fighting for the space between rotors. The ports are pretty good size compared to stock Mazda ports. Future performance testing and potentially porting will tell the limits of the port design.
One of my main concerns when I have been musing on how to up the power dial on rotaries is cooling the rotors enough, because a cool rotor can be made out of lighter stuff than an extremely hot rotor.
If the rotors are charge-cooled, does that mean oil is no longer used internally to cool them?
Cooler rotors=more power and rev potential, I would imagine.
Last edited by Smilodon; 11-02-05 at 06:07 PM.
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11-03-05, 12:08 AM
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But, considering that one of the main enemies of highly boosted rotaries is the rotors heating up excessively (isn't it a contributor to detonation? would it not make for more boost potential to have the rotors cooled by the incoming air? Because the amount of incoming air heat capacity is going to be far more directly related to boost at that time than it is to the oil flow, which remains the same for any given RPM whether you have 0 or 30 PSI of boost.
11-03-05, 01:22 PM
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No, I think it would be horrible to try to boost for more power.
Compressing the air for boost will add heat to it before it even enters the rotor. You can intercool it, but it will still be higher than ambient so it will be worse for cooling.
Then there will be a lot more heat in the rotor to dissapate from the higher power levels- that is even more heat added to the intake charge before it enters the intake ports.
You would have to dramatically drop the compression ratio to have the same detonation/preignition resistance as an oil cooled rotor Wankel at any set boost level.
The one area this charge cooled rotary might work well boosted for just these reasons is in a turbo diesel application? I would be interested in more information on this Wankel running on diesel! Hmm, boosted diesel Wankel with propane injection
Compressing the air for boost will add heat to it before it even enters the rotor. You can intercool it, but it will still be higher than ambient so it will be worse for cooling.
Then there will be a lot more heat in the rotor to dissapate from the higher power levels- that is even more heat added to the intake charge before it enters the intake ports.
You would have to dramatically drop the compression ratio to have the same detonation/preignition resistance as an oil cooled rotor Wankel at any set boost level.
The one area this charge cooled rotary might work well boosted for just these reasons is in a turbo diesel application? I would be interested in more information on this Wankel running on diesel! Hmm, boosted diesel Wankel with propane injection
11-03-05, 01:40 PM
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It remains to be seen. But, as I was saying, the boosted air passing through the rotor, even though it is above ambient, would still be FAR cooler than the rotor, thus cooling the rotor. In addition to that, it would be far cooler than the engine oil, also. If engine oil is cooler than boosted intake air, then why doesn't anyone use their engine oil to intercool their intake air with an oil/air heat exchanger?
Intake air will be cooler and cool the rotor better than engine oil, I think.
This is all in the realm of theory, of course, but the easiest way to find out would be for Rotamax to set up a turbo rig right beside an identical 13b, and see which behaves better, which can produce more power, which can stand more boost, which one's rotors stay cooler, etc. etc. I don't think having to use a larger intercooler is too high a price to pay for an engine that weighs half as much as a 13b.
If the Rotamax wins, then they can sell turbo motor packages, too.
Intake air will be cooler and cool the rotor better than engine oil, I think.
This is all in the realm of theory, of course, but the easiest way to find out would be for Rotamax to set up a turbo rig right beside an identical 13b, and see which behaves better, which can produce more power, which can stand more boost, which one's rotors stay cooler, etc. etc. I don't think having to use a larger intercooler is too high a price to pay for an engine that weighs half as much as a 13b.
If the Rotamax wins, then they can sell turbo motor packages, too.
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