Attained 15000 rpm with my engine; no problems
11-07-2007, 08:38 PM
#51
w8nkel
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well, tell us how your car is running after a couple of years...keep listening to your mazda tech and update us! please, please, please! I want to learn the way of the idiot....lol not saying u r, but the mazda tech is.
11-07-2007, 09:07 PM
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11-08-2007, 01:13 AM
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What Transmission?
In your original post you stated "For sure I can tell you that the engine, the transmission and everything else..." I'm quite sure you have neither a PSRU (propeller speed reduction unit) or a TRANSMISSION. But you had my attention. I saved it under my You Tube favorites next to the "Martin Mars Lake Elsinore" fire tanker/bomber which I saw in person. My GF had to evacuate due to the recent CA wildfires. I'm a rotorhead and a wing nut.
11-08-2007, 07:11 AM
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In your original post you stated "For sure I can tell you that the engine, the transmission and everything else..." I'm quite sure you have neither a PSRU (propeller speed reduction unit) or a TRANSMISSION. But you had my attention. I saved it under my You Tube favorites next to the "Martin Mars Lake Elsinore" fire tanker/bomber which I saw in person. My GF had to evacuate due to the recent CA wildfires. I'm a rotorhead and a wing nut.
I was prepared for this!
11-08-2007, 07:14 AM
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Oh, and by the way, I don't have an Rx-8, even though I really wish I had...
11-08-2007, 09:11 AM
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Now, I hopefully have a few minutes of computer use ( 
) to describe everything a little bit better for those who don't know already.
The little engine is a single rotor, peripherial inlet and exhaust, carburated wankel. It displaces 0.30 cu inches (4.97 cc) and has a rated power output of 1.27 bhp @ 17000 rpm, with a maximum allowed speed of 18000 rpm. It's air cooled and uses a total loss lubrication system, with the oil being carried in and out together with the fuel.
According to the user manual, the MINIMUM required oil content for the fuel is 20%, with 25% being much better and with the further requirement that at least part of this oil content must be castor oil. Just look at the video: at about 3:10 in, I give suddently full throttle after a long idle. During the rev up, a white stuff is emitted by the exhaust: that's not smoke; that's boiling hot oil that accumulates in the muffler during idle. An interesting fact is that this engine has no side or corner seals, nor cutoff seals or similar, only apex seals. That's probably a cost saving measure, but it also helps in bringing oil to the main and rotor bearings (by the way, the front bearing is a ball bearing, while the rotor and rear ones are needle bearings).
The engine is designed to run on methanol, possibily with a small percentage of nitromethane added. In previous tests, the engine had no problems in revving over 14000 rpm with a bigger prop and with a (on purpoue) very rich AFR while running a higher percentage of nitromethane. The drawback is that it got insaneously hot, and it took 10 minutes after being shut down to become cool enough to touch. The drastic performance increase produced by nitromethane leads me to believe this is a low compression engine, but I have no way to check this.
Even with little nitromethane the engine runs hot; this produces an interesting side effect: adding synthethic oil to the mixture produces results similar to those of the addition of smoke fluid to a conventional engine. Basically, synth oil can't stand up to the temperatures inside, and burns, creating that impressive smoke cloud.
Finally, in the video the engine didn't reach 15000 rpm (at least the tachometer never read that speed, although I was having problems in getting it to read the correct value), but I grant you that that same engine with that same propeller and with that same fuel was tached at over 15000 a few weeks ago. Probably using fresh fuel instead of the nearly one year old fuel I was using in the video would help...
I'll leave you with a question that I kind of expected, but that no one asked: how can a carburated engine run without an ignition system?
(if you already know the answer, please don't post it )
VIDEO DESCRIPTION
1:05 The correct value is above 13000. That red thing is an optical tachometer, and the number is the detected engine rpm.
1:20 huge prop cavitation noise.
3:10 That white stuff being blown out before the blue smoke is boiling hot oil
3:35 I didn't want it to stop; I set the idle speed to low...
3:40 Starting procedure. Notice that I had inadvertently covered the microphone with my hand, so the sound is slightly wrong till 3:57.
4:07 Setting the carburator mixture to compensate for the decreasing fuel level in the tank.
4:25 I think I need a catalyst...
5:13 Trying to see if I can get the tachometer to work correctly.
5:52 The rattling sound produced by the rotor gear. It's a normal sound of this engine.
) to describe everything a little bit better for those who don't know already.The little engine is a single rotor, peripherial inlet and exhaust, carburated wankel. It displaces 0.30 cu inches (4.97 cc) and has a rated power output of 1.27 bhp @ 17000 rpm, with a maximum allowed speed of 18000 rpm. It's air cooled and uses a total loss lubrication system, with the oil being carried in and out together with the fuel.
According to the user manual, the MINIMUM required oil content for the fuel is 20%, with 25% being much better and with the further requirement that at least part of this oil content must be castor oil. Just look at the video: at about 3:10 in, I give suddently full throttle after a long idle. During the rev up, a white stuff is emitted by the exhaust: that's not smoke; that's boiling hot oil that accumulates in the muffler during idle. An interesting fact is that this engine has no side or corner seals, nor cutoff seals or similar, only apex seals. That's probably a cost saving measure, but it also helps in bringing oil to the main and rotor bearings (by the way, the front bearing is a ball bearing, while the rotor and rear ones are needle bearings).
The engine is designed to run on methanol, possibily with a small percentage of nitromethane added. In previous tests, the engine had no problems in revving over 14000 rpm with a bigger prop and with a (on purpoue) very rich AFR while running a higher percentage of nitromethane. The drawback is that it got insaneously hot, and it took 10 minutes after being shut down to become cool enough to touch. The drastic performance increase produced by nitromethane leads me to believe this is a low compression engine, but I have no way to check this.
Even with little nitromethane the engine runs hot; this produces an interesting side effect: adding synthethic oil to the mixture produces results similar to those of the addition of smoke fluid to a conventional engine. Basically, synth oil can't stand up to the temperatures inside, and burns, creating that impressive smoke cloud.
Finally, in the video the engine didn't reach 15000 rpm (at least the tachometer never read that speed, although I was having problems in getting it to read the correct value), but I grant you that that same engine with that same propeller and with that same fuel was tached at over 15000 a few weeks ago. Probably using fresh fuel instead of the nearly one year old fuel I was using in the video would help...
I'll leave you with a question that I kind of expected, but that no one asked: how can a carburated engine run without an ignition system?
(if you already know the answer, please don't post it
)VIDEO DESCRIPTION
1:05 The correct value is above 13000. That red thing is an optical tachometer, and the number is the detected engine rpm.
1:20 huge prop cavitation noise.
3:10 That white stuff being blown out before the blue smoke is boiling hot oil
3:35 I didn't want it to stop; I set the idle speed to low...
3:40 Starting procedure. Notice that I had inadvertently covered the microphone with my hand, so the sound is slightly wrong till 3:57.
4:07 Setting the carburator mixture to compensate for the decreasing fuel level in the tank.
4:25 I think I need a catalyst...
5:13 Trying to see if I can get the tachometer to work correctly.
5:52 The rattling sound produced by the rotor gear. It's a normal sound of this engine.
11-08-2007, 01:50 PM
#65
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I've got an OS .30 rotary that was built sometime around 1974 or so. It was used and I paid $300 for it. Cool little piece. I'll probably never run it though. I don't think it was a waste.
11-08-2007, 02:15 PM
#66
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This is the proper link:
http://www3.towerhobbies.com/cgi-bin...&I=LXPVE3&P=SM
http://www3.towerhobbies.com/cgi-bin...&I=LXPVE3&P=SM
RG, if yours was built then, it should be the very first version with the cooling ring and the side port intake. Can you confirm?
11-08-2007, 02:22 PM
#67
No, I wanted to show that it's possible to spend a lot more on engines if one wants to. By the way, that's the type II, and I have the ("less civilized", so to say) type I.
RG, if yours was built then, it should be the very first version with the cooling ring and the side port intake. Can you confirm?
RG, if yours was built then, it should be the very first version with the cooling ring and the side port intake. Can you confirm?
Well, yeah, you can spend a TON on RC engines.
The twin gasser on my 3D plane was at least $1k.
11-08-2007, 03:19 PM
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