Posts: 501
Joined: 12/12/2001 From: Colorado Springs,
CO, USA Status: offline
I think I just dropped the cost of my RC addiction way down over the long haul. Today I converted an ASP 1.08 glow engine to run on E85 biofuel with 18% castor. E85 is available here at about 7 gas stations, and I bought two gallons yesterday for $1.99 a gallon. I used the stock glow carburetor. Since E85 is 85% alcohol, there's no need for a gasoline carb. I added a CH Ignitions spark system to the engine. I installed the spark ignition by drilling a small 1/8" hole/recess in the prop drive washer and installed a tiny 1/8" diameter magnet, added a Hall Effect pickup with hose clamp and timed it to 30deg BTDC per the CH Ignitions instructions, replaced the glow plug with a 1/4-32 spark plug, and connected up a fuel tank with gasoline lines and stopper. Connected spark lead to spark plug, and switched it on. It runs really smooth, and all I had to do was lean the top end 1/4 turn and the bottom end 1/8 turn. The needle wasn't as broad in adjustment as 15% nitro, it was about like FAI fuel, two clicks either side of peak. I think I could run my Raptor 50, my Saito 120, and Saito 90 on this stuff. I am running E85 with 18% castor oil. I wonder just how much castor oil I really need since the 15% gasoline has more lubricity than straight alcohol. I have found a source of beauty supplies on the net that sells castor for $10 a gallon, I'll give that stuff a try. The exhaust smells really good, like straight castor glow fuel. I know it all sounds like a lot of work to beat the cost of glow fuel, but I'm just sick of paying for glow fuel. Maybe I'm a future gasser, but I really don't want to go giant scale and I have all these glow motors. The break-even point isn't that far out on the investment in the ignition module. My tach broke yesterday, so I'll update this with some hard RPM numbers when I replace it. I did get some head temps, they were about 250f. I wonder how much castor I really need with this setup. The 15% gasoline has more lubricity than the usual methanol/15% nitro mix. I tried some 12% castor E85 mix, but I don't know how the conrod's bottom end will do on that. Can someone explain to me why the glow car engines can run on 10% oil? They are revving high with less cooling than an airplane motor, but just a bushing on the lower end. -Tom Andersen Colorado Springs, CO http://www.hoverbatics.com
Posts: 2709
Joined: 5/3/2003 From: ASH FORK,
AZ, USA Status: offline
I too have wondered why the car engines spec less oil. The only thing I can think of personally is that they spend less time at high throttle/power settings than an airplane engine. Kind of "zoom, zoom, zoom, whereas an airplane engine is WAAAHHHH..."
I think it is also highly likely that a person could run much less the the usual 18% or so oil spec'd for the airplane engines, if you were REALLY careful NEVER to have a lean run. I think other than that, the only real answer will be if/when someone cares to do some extensive testing, and is willing to possibly lose an engine or two "in the pursuit of higher knowledge"...
Reportedly, OS Engines has developed a modified engine, I believe one of their .46 size engines, to run on ethanol with a glow plug. They said that they modified the head and the glow plug to do so. I would like to know more details about what they did, but that was all the article I read in R/C Report said. I contacted the writer, and he didn't have any more info than had been printed.
Time will tell...
AV8TOR
< Message edited by av8tor1977 -- 10/12/2007 2:46:13 AM >
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If it's not scary, it's NOWHERE NEAR powerful enough!!
Posts: 862
Joined: 2/18/2004 From: Ovid, MI, USA Status: offline
A engine on a plane or a bote is under a load at all times. The car engine is under a load only when it is exselarating. ( speeding up. i cant spell) It take much less power to keep a car at one speed. about a 10% of the power of the engine. that is why a plane and a bote needs more oil then the car.
Posts: 501
Joined: 12/12/2001 From: Colorado Springs,
CO, USA Status: offline
Yes OS Engines is coming out with a .55 engine. There is a web page showcasing the new AX-55BE engine from OS, I can't find it but I have seen it. They changed the combustion chamber, probably to increase the compression. It's funny that they say it has more power than their .46 engine. Those new glow plugs will be interesting. I wonder how long it will take for someone to make some biofuel glow plugs in standard sizes.
Posts: 8
Joined: 12/15/2005 From: , LA, USA Status: offline
I found a link to O.S.s BioEthanol engine. it is: http://www.os-engines.co.jp/english/bio_eng/ The article said they were due out in Japan in Summer of '07 and they even have a video clip of a float plane flying with one. The price was 21,000 yen, or about $180.00 U.S. It would be worth it to get away from $30.00/gallon glow fuel.
Posts: 2709
Joined: 5/3/2003 From: ASH FORK,
AZ, USA Status: offline
E-85 is a new fuel that is being sold optionally at gas stations in some parts of the country. It is composed of 85% ethyl alcohol, and 15% gasoline.
I tried it in our Gas/Glow experiments and couldn't get it to work very well. It doesn't have the methyl alcohol necessary for the catalytic reaction with the glow plug. That's why I'm very interested to see what OS has done to be able to run it in a glow setup.
AV8TOR
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If it's not scary, it's NOWHERE NEAR powerful enough!!
Posts: 501
Joined: 12/12/2001 From: Colorado Springs,
CO, USA Status: offline
Today I converted my Saito 120 to spark ignition and E85. The Saito carb is fine on top end and idle, but midrange is very rich. I think these Saito engines were set up to use high-nitro fuels, up to 30%, so they flow lots of fuel in the midrange. This leads me to think that an engine set up for FAI or moderate nitro would work better with the E85. I need to change the spraybar profile a little in the midrange. I know it's the mixture because I can pinch the fuel line and smooth it out. I soldered the hole in the spraybar closed, and then opened it back up again with a little smaller slit. The Saito spraybar is very difficult to work on, I couldn't get it out of the carb body to save my life. I resorted to scraping at it with a sharpened screwdriver and hobby blade. We'll see tomorrow if that is better. I know it's a lot leaner in the midrange now, maybe too lean? One thing I recently learned is that nitromethane has a fuel/air ratio of 1: 1.6 which is very different from methanol at 1:6 or ethanol which is around 1:9, or gasoline which is 1:15. I'll bet E85 is somewhere around 1:10 since it's a mixture. So anything designed to run a lot of nitro glow fuel is going to be very rich on low-nitro glow fuel or ethanol or gasoline. I never was really impressed with the way the engine transitioned on even 15% nitro glow fuel, so I know why the midrange is even richer on this carb. The ASP 1.08 I converted was designed to run on low nitro fuel. I was able to dial that carb in to perfection, utter perfection. That motor never ran so good. Oh I also converted my 18cc Poulan leaf blower to E85 today, that was no more complicated than just opening the main needle valve a half turn. I started it up with gasoline in the fuel lines, and gradually it burned that out and transitioned to E85 with 4% castor. That made finding the new needle position real easy, I just kept adjusting it as it ran until it smoothed out and stopped changing. It is so much nicer to work with the E85, it has a slight gasoline odor but it's not a stinkbomb on your hands like gasoline. My experience with this fuel change has shown me why in the past I've had to change glow fuels to really dial in an engine. I cannot imagine flying with 30% nitro like many Saito owners do, but now I know why those engines really like it. -Tom
Posts: 501
Joined: 12/12/2001 From: Colorado Springs,
CO, USA Status: offline
Yes, I am very interested in diesel conversions as well. I do like the idea of cheap fuel, high torque, and low fuel consumption but can you get away without using ether in the fuel or buying expensive DDD fuel? I have an OS 46FX I would like to convert. One thing I'd like to try is running diesel fuel in my spark converted Saito 120. That's a normal-compression use of diesel, probably not as efficient or powerful as diesel but probably easier to set up and run, but probably not as powerful as the E85 conversion that runs on mainly alcohol. Someone mentioned this was done for an RPV program successfully, but I bet they made it run on JP-8 (or kerosene) because that is what the military requires, perhaps not the optimal fuel for hobbyists, although it's cheap and readily available everywhere. What is homebrew model diesel fuel comprised of, just kerosene and oil? Maybe a Perry carb is what I need for my Saito 120, they have a midrange control. Do most diesel conversions require a Perry carb?
Posts: 501
Joined: 12/12/2001 From: Colorado Springs,
CO, USA Status: offline
Yes, I am very interested in diesel conversions as well. I do like the idea of cheap fuel, high torque, and low fuel consumption but can you get away without using ether in the fuel or buying expensive DDD fuel? I have an OS 50SX-H in a Raptor 50 I would like to convert. I bet the extra torque would be great in a heli. I run 1850 head speed with 8.5:1 ratio, and I use a governor so that's a constant 15,725rpm. Do you think I could get that rpm with a diesel? I could probably do with less rpm about 1700 head speed (14450rpm) if I had more torque to back it up. One reason I use the 1850 head speed is to store some energy for pitch changes and get the engine into it's power band. Maybe a diesel though, would be a little hard on the geartrain in a heli? One other thing I'd like to try is running diesel fuel in my spark converted Saito 120. That's a normal-compression use of diesel, probably not as efficient or powerful as diesel but probably easier to set up and run, but maybe not as powerful as the E85 conversion that runs on mainly alcohol. Someone mentioned that was done for an RPV program successfully, but I bet they made it run on JP-8 (or kerosene) because that is what the military requires, and perhaps it's not the optimal fuel for hobbyists, although it's cheap and readily available everywhere. What is homebrew model diesel fuel comprised of, just kerosene and oil? Do most diesel conversions require a Perry carb? The fuels are so different, it's got more energy than gasoline even. Update on the Saito 120 E85 conversion, my carb modification worked. I closed up the low end of the spraybar with solder and reopened it with a much leaner profile and now it transitions nice, runs smooth in the midrange and ok on top end. The idle is nice, it's very lean and varies a little bit, but definitely flyable all around. I can't wait to try it out. -Tom
Posts: 1588
Joined: 6/24/2003 From: Crystal Lake,
IL, USA Status: offline
Kerosene fuel in a spark ignition engine is a bit tricky to start. You would generally start it on an auxiliary tank of gasoline, then go to the on board kerosene. Or you need to preheat the engine, or intake manifold. You have to be a little careful with the compression ratio, you don't want to get too high or it will preignite.
Diesel may or may not make more torque. Not every glow engine conversion makes more power and torque. I have an FX awaiting conversion but don't have any numbers for performance on diesel.
Posts: 823
Joined: 6/26/2006 From: Spring, TX, USA Status: offline
I am running a SuperTigre GS40 on E85 in a Super Sportster. I add 15% nitro and the oil is 18% blended at 80/20 synth/castor. It runs virtually identical to glow fuel with the exception of about 1 to 200 rpm's lost on the top. I have to run an OS F plug in it to get the idle low and smooth but otherwise it runs great. I also had to lean the HS needle about 1/2 turn and I didn't pay attention to how much I leaned the low needle but it wasn't much, maybe a 1/4 turn or so. It is just a tiny bit rich in the mid range but not unacceptable. Overall it's been a great little project.
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Raptor 50 V2 OS 50 Hyper, T-Rex 450XL CDE, Spektrum DX7, SuperTigre OS FOX Saito Enya Jett TT
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I converted a glow engine to run on E85 - 
