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All Forums >> Glow Engines, Gas Engines, Fuel & Mfg Support Forums >> RC Fuels >> mwright,
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mwright, - 4/5/2003 10:02:08 PM   
rmteo1


 

Posts: 89
Joined: 5/12/2002
From: Longmont, CO,
Status: offline 		Check your mailbox (the one in your driveway), there may be some goodies in it.

RT

< Message edited by rmteo1 -- Apr 6 2003 4:48AM >

(in reply to mwright)
       Post #: 26

Re: Dave - 4/6/2003 12:41:50 AM   
Diesel Dave-RCU


 

Posts: 46
Joined: 12/22/2002
From: Monroe, MI, USA
Status: offline 		[QUOTE]Originally posted by mwright
I should just quit my day job and blend fuel... don't think the wife and three kids would take well to that idea.

Take care.

Marcus [/QUOTE]

Well you could become head of fuel research, and development for Davis Model Products. But the commute to Connecticut every day for work, might wear on you a bit.

Dave

(in reply to mwright)
       Post #: 27

Ether - 4/7/2003 7:23:11 PM   
mwright


 

Posts: 184
Joined: 12/29/2001
From: King, NC, USA
Status: offline 		Did some more blending this weekend. Tried some standard and some not so standard things. These things seem to run on almost anything if ether is present in 20 to 30%.

I have gone to a 12 x 6 APC, I can routinly get 9600-9800 rpms but backed off to 9400 on the two best kero and FAME blends. That's pretty good for a bushing 40.

Another observation, the new Great Planes fuel tank black "stopper" is resistant to prolonged exposure to the kero.

Marcus

(in reply to mwright)
       Post #: 28

Made some bio diesel, now what? - 4/14/2003 7:45:06 AM   
Bighead


 

Posts: 34
Joined: 4/1/2003
From: WORCESTER, MA, USA
Status: offline 		"The 10% oil, 20% ether, 68% FAME was the best FAME run and "felt" equal to the kero based run."


- is this still the overall winner?

- where the hell can just anyone get ether?

- does it really smell like french fries?

(in reply to mwright)
       Post #: 29

Made some bio diesel, now what? - 4/14/2003 11:50:31 PM   
mwright


 

Posts: 184
Joined: 12/29/2001
From: King, NC, USA
Status: offline 		Bighead,

So far I would say that is the best FAME blend. Some people get ether from tractor supply stores. I think it's only ~80% ether and the rest is small hydrocardons.

As far as getting ether, that's the issue that started the testing. There were reports that FAME did not need ether so that make mixing it was much easier. But after running some more this weekend I'd say that ether is the most important part of the mix. I have now run the OS 40 on pure soybean oil (70% and 30% ether, not optimized). In one of the previous replies Dave explained that the ether is compressed then ignites which in turn burns everything else around it. If that happens to be cooking oil, FAME, castor or kero then it too will burn. I almost see these things as a dispose-all for oily hyrocarbons.

(in reply to mwright)
       Post #: 30

Made some bio diesel, now what? - 5/7/2003 6:26:34 AM   
greg pickard


 

Posts: 9
Joined: 2/21/2003
From: victoria bc canada
Status: offline 		i live in canada and cannot get amyl-nitrate witch lowers the flashpoint of regular diesel fuel also called cetane told to me by a chemist at imperal oil any body know of an equivlant that i can easly get here because this chemist i spoke to said that amyl nitrate cumbusts at 157 degrees all on its own so i think this is a key in easy starting because i canot get anymore than a pop with quickstart either because it is not pure enought.

(in reply to mwright)
       Post #: 31

Made some bio diesel, now what? - 5/7/2003 8:11:13 AM   
downunder-RCU



Posts: 1125
Joined: 12/27/2001
From: Adelaide, South Australia
Status: offline 		I don't know if they're easier to find or not but you can use either amyl nitrite (as against nitrate) or IPN (iso propyl nitrate). With amyl nitrite you need about twice as much so start around 2.5 to 3%. IPN can be used at around the 1.5% mark.

Just for interest's sake, I know for sure that a diesel will run on just IPN because I once put a few drops in an old Mills .75 and it started first flick

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       Post #: 32

Made some bio diesel, now what? - 5/7/2003 9:31:36 AM   
greg pickard


 

Posts: 9
Joined: 2/21/2003
From: victoria bc canada
Status: offline 		thank you for the info on the isoproply-nitrate i will see if my country will sell this to me. ha ha .

(in reply to mwright)
       Post #: 33

Posed question - 5/23/2003 6:41:55 AM   
Hobbsy



Posts: 10129
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: online 		I don't think anyone responded to the question above about why it is necessary to richen the mixture as the ether level is reduced. Mr. Davis touches on this in his Diesel 101 pamphlet, richening the mixture has the effect of raising the compression pressure because richening the mixture increases the amount of solids in the combustion chamber, since very little of this stuff evaporates.

_____________________________

I can't ride my Harley and fly at the same time, what a bummer.

(in reply to mwright)
       Post #: 34

Made some bio diesel, now what? - 5/23/2003 8:02:37 AM   
downunder-RCU



Posts: 1125
Joined: 12/27/2001
From: Adelaide, South Australia
Status: offline 		hobbsy...if you calculate the volume of mixture that goes into the combustion chamber every time then you'd be amazed at how tiny it is. If you then calculate the volume of oil (the only non-evaporative solid) it's about 5 times smaller again. This tiny volume is so small compared to combustion chamber volume at max compression it can have virtually no effect.

(in reply to mwright)
       Post #: 35

More bio fuel stuff - 6/1/2003 4:59:48 PM   
Hobbsy



Posts: 10129
Joined: 12/2/2001
From: Colonial Beach, VA, USA
Status: online 		I ran my Fox .74 conversion on bio fuel to see if the fuel would even burn. It burns and burns very well. I used RedMax concentrate, 65% ether, 30% castor and 5% ignition enhancer. I mixed a quart of this with two quarts of soybean oil. The ingredient percentages should then be about 21% ether, 10% castor and 1.5% ignition enhancer. Some of you percentage experts feel free to correct me if this is wrong. I had the engine set up for Davis fuel and instantly realized that the compression was too high. Even with the compression screw backed out all the way the compression was too high above half throttle. This was not a problem below 7,000 rpm. I ran out a 16 OZ tank in the 5,500 to 6,000 rpm range just to let it run. Since then I have made two shims from one of those throw away aluminum cake pans and will try it again. I also want to try it in my PAW .60. I'll let you know how it goes.

< Message edited by hobbsy -- Jun 4 2003 12:32PM >

_____________________________

I can't ride my Harley and fly at the same time, what a bummer.

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       Post #: 36

Made some bio diesel, now what? - 6/4/2003 8:58:33 AM   
bobi


 

Posts: 224
Joined: 4/9/2002
From: bangkok, THAILAND
Status: offline 		what prop are u running on the .74 fox.
could you increase the ether to ~30% and see how it runs.?
the soybean oil u r using ... is this the cooking oil ??

(in reply to mwright)
       Post #: 37

Re: More bio fuel stuff - 6/4/2003 3:00:43 PM   
Rudeboy



Posts: 3243
Joined: 12/9/2002
From: Bejing, BELGIUM
Status: offline 		[QUOTE]Originally posted by hobbsy
I ran my Fox .74 conversion on bio fuel to see if the fuel would even burn. It burns and burns very well. I used RedMax concentrate, 65% ether, 30% castor and 5% ignition enhancer. I mixed a quart of this with two quarts of soybean oil. The ingredient percentages should then be about 21% ether, 10% castor and 1.5% ignition enhancer. Some of you percentage experts feel free to correct me if this is wrong. I had the engine set up for Davis fuel and instantly realized that the compression was too high. Even with the compression screw backed out all the way the compression was too high above half throttle. This was not a problem below 7,000 rpm. I ran out a 16 OZ tank in the 5,500 to 6,000 rpm range just to let it run. Since than I have made two shims from one of those throw away aluminum cake pans and will try it again. I also want to try it in my PAW .60. I'll let you know how it goes. [/QUOTE]

Well you almost had the percentages right Dave...

They are actually:
21.67% ether
10% castor oil
1.67% ignition enhancer
66.67% soybean oil


But seriously now... How does the engine smoke on the mix stated above?
I think the reason for the excessive compression is because you're burning pure oil... well not pure, but you know what I mean.
What happens is that at lower rpm levels only very little of all that oil evaporates and subsequently burns. But as the rpm rises, the temperature and pressure in the cilinder rise also, so more of the oils evaporate, which rises the temp and pressure even more,... etc. etc. .... chain reaction, you get the picture.
My guess is that you have to set the needle fairly rich in order to get enough ether up there to keep combustion going with all these heavy oils in the fuel. In fact, I think your engine is running almost completely on the ether and ignition enhancer...The result of this is that at higher rpms too much oil starts to evaporate which in turn causes over-compression...

< Message edited by Rudeboy -- Jun 4 2003 10:16AM >

_____________________________

Revver Brother #33
...I think it needs more power...

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       Post #: 38

Made some bio diesel, now what? - 6/4/2003 7:43:40 PM   
mwright


 

Posts: 184
Joined: 12/29/2001
From: King, NC, USA
Status: offline 		Sorry to not have kept up with the thread but I've been finishing up a Kadet Senior and trying to get a little flying in.

Dave - If the compression is too high then maybe decreasing the % ether may help, but with too low % ether I have to open the high speed needle and transistion starts to suffer. Do you notice a difference in the pitch of your exhaust sound?

A few weeks ago I mixed up 20% ether and 80% soybean oil (Crisco Veg oil is soyben oil) and ran the engine for 30 minutes. I tried and tried to get it right, the transistion was poor but wide open was good.

I am ready to mount my 40FP on a plane and see how it performs in the air. Not sure about which fuel to use, I am leaning towards the kero based stuff just due the lower exhaust pitch but the bio diesel smells better and is easier to handle.

(in reply to mwright)
       Post #: 39