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Old 12-02-2013, 08:15 AM
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Hi Fellers,
I'd like to be included in the club ! Also I'd like your opinions. I have a 17 cc gas saito I'm looking for a .60 size ARF Bi Plane. I like a PT 17 Stearman or something that doesn't have to land at 140mph. Fairly light wing loading. Any ideas? Thanks, John Pope
Old 12-02-2013, 11:41 AM
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Originally Posted by Charley
Read the above linked article. It should be noted that the author still runs 14% oil in his methanol mix. That's still a lot more than 16:1 in a gas mix. Let's get this straight: 16:1 is 6.25% oil. Lots less than you can get away with in a bushing engine on methanol.

CR
Here is a snip from that article-Spark engines do not like high oil and nitro content. I mix my own and use only 10% nitromethane and only 14% Klotz synthetic oil.
Some say you can go as low as 10%oil and right down to zero nitro."

As far as your 16:1 gas/oil mix being a better lubricator than 9:1 methanol/oil mix in an engine that has spark ignition?

Since we are both specifying Klotz oil we can make a mathematical comparison of the available lubrication for an engine burning either mix.

1st of all let’s keep the MATH simple since you seem to become annoyed when I "play with numbers".

Let's say we run both engines @ WOT for 10 minutes that keeps everything in decimal.

16:1 means you have 17 “parts" mix,16/17 gas & 1/17 oil so 16:1 = 1/17 = .588 or 5.88% lube. Let's keep it simple & give the gas engine the benefit of the doubt & say 6% lube.

My methanol mix is 9:1 which means I have 9/10 methanol & 1/10 lube so 1/10 = 10% lube.

Again just to keep thing simple & give the benefit of the doubt to the gas engine, let’s say that our methanol engine will burn 1 1/2 times as much fuel as the same engine burning gas. In reality the alcohol burning engine would probably burn more than 1 1/2 times as much fuel, but let's give the benefit of the doubt to the gas engine & again, keep the MATH simple.

Let's say that the engine burning gasoline burned 10oz of gas in 10 minutes @ WOT.
That means that 10 x .06 = .6 oz of oil was available to lube the "gas" engine in those 10 minutes.

Now set up the same engine & tune it for methanol. 1.5 X 10oz means the alcohol burning engine will use 15oz of fuel.
15 X .10 = 1.5 oz of oil was available to lube the "alcohol" engine in those 10 minutes. We can drop the decimal points so we have 15/6 = 2.5.

From personal testing I know that the alcohol burning engine, will be running @ least 40°F cooler CHT than the gas burning engine. It has 2 ˝ times as much oil available to lubricate the engine.

Granted, if I tuned that alcohol engine properly @ 36° ignition advance it would produce about 5% more RPM (say 400 RPM in a 30cc Saito) than a gas engine running 28° maximum ignition advance for gasoline, but I still think 2 ˝ times as much oil should be able to lubricate it sufficiently even at the higher power output.


Last edited by SrTelemaster150; 12-02-2013 at 11:45 AM.
Old 12-02-2013, 12:48 PM
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Originally Posted by SrTelemaster150



Here is a snip from that article-Spark engines do not like high oil and nitro content. I mix my own and use only 10% nitromethane and only 14% Klotz synthetic oil.
Some say you can go as low as 10%oil and right down to zero nitro."

As far as your 16:1 gas/oil mix being a better lubricator than 9:1 methanol/oil mix in an engine that has spark ignition?

Since we are both specifying Klotz oil we can make a mathematical comparison of the available lubrication for an engine burning either mix.

1st of all let’s keep the MATH simple since you seem to become annoyed when I "play with numbers".

Let's say we run both engines @ WOT for 10 minutes that keeps everything in decimal.

16:1 means you have 17 “parts" mix,16/17 gas & 1/17 oil so 16:1 = 1/17 = .588 or 5.88% lube. Let's keep it simple & give the gas engine the benefit of the doubt & say 6% lube.

My methanol mix is 9:1 which means I have 9/10 methanol & 1/10 lube so 1/10 = 10% lube.

Again just to keep thing simple & give the benefit of the doubt to the gas engine, let’s say that our methanol engine will burn 1 1/2 times as much fuel as the same engine burning gas. In reality the alcohol burning engine would probably burn more than 1 1/2 times as much fuel, but let's give the benefit of the doubt to the gas engine & again, keep the MATH simple.

Let's say that the engine burning gasoline burned 10oz of gas in 10 minutes @ WOT.
That means that 10 x .06 = .6 oz of oil was available to lube the "gas" engine in those 10 minutes.

Now set up the same engine & tune it for methanol. 1.5 X 10oz means the alcohol burning engine will use 15oz of fuel.
15 X .10 = 1.5 oz of oil was available to lube the "alcohol" engine in those 10 minutes. We can drop the decimal points so we have 15/6 = 2.5.

From personal testing I know that the alcohol burning engine, will be running @ least 40°F cooler CHT than the gas burning engine. It has 2 ˝ times as much oil available to lubricate the engine.

Granted, if I tuned that alcohol engine properly @ 36° ignition advance it would produce about 5% more RPM (say 400 RPM in a 30cc Saito) than a gas engine running 28° maximum ignition advance for gasoline, but I still think 2 ˝ times as much oil should be able to lubricate it sufficiently even at the higher power output.

So much MATH, my head hurts!! (you know, these new smiley faces are lame!!)

The math shows that the methanol version is running more oil through it as you calculate, no disagreement there. But I, being a cheapskate, was saying that the oil is typically the most expensive part of the fuel and needing LESS oil is my goal, not power or cooler running (withing reason, of course).
Old 12-02-2013, 01:01 PM
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Originally Posted by hsukaria
So much MATH, my head hurts!! (you know, these new smiley faces are lame!!)

The math shows that the methanol version is running more oil through it as you calculate, no disagreement there. But I, being a cheapskate, was saying that the oil is typically the most expensive part of the fuel and needing LESS oil is my goal, not power or cooler running (withing reason, of course).
The post I responed to was not about cost, but about whether of not 10% lube was sufficient W/methanol.

Indeed, if 6% klotz is sufficient W/gasoline why wouldn't 6% or perhaps even less be sufficient W/methanol when spark ignition is used. considering the higher fuel consumpsion?

I was told that one of the reason for higher % lubucation W/methanol was due to the fact that lubes used W/gasoline were better lubricaters.

In this case aren't we talking about the same lube?

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Old 12-02-2013, 01:50 PM
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Originally Posted by SrTelemaster150
The post I responed to was not about cost, but about whether of not 10% lube was sufficient W/methanol.

Indeed, if 6% klotz is sufficient W/gasoline why wouldn't 6% or perhaps even less be sufficient W/methanol when spark ignition is used. considering the higher fuel consumpsion?

I was told that one of the reason for higher % lubucation W/methanol was due to the fact that lubes used W/gasoline were better lubricaters.

In this case aren't we talking about the same lube?
WAIT! I missed something.

I could have sworn that the reason gassers use ~ 5% or less oil was due to the use of needle bearings in the big end of the con rod.

Who suggested the lubricants used in gas mixes were better? I don't believe it! The ONLY benefit *I* see is that you CAN get synthetic lubes that will burn with the gas charge and I don't castor does.
Old 12-02-2013, 02:07 PM
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Originally Posted by SrTelemaster150
The post I responed to was not about cost, but about whether of not 10% lube was sufficient W/methanol.

Indeed, if 6% klotz is sufficient W/gasoline why wouldn't 6% or perhaps even less be sufficient W/methanol when spark ignition is used. considering the higher fuel consumpsion?

I was told that one of the reason for higher % lubucation W/methanol was due to the fact that lubes used W/gasoline were better lubricaters.

In this case aren't we talking about the same lube?
That is the question I have been asking around. The gas lubes now have the new Ester oils, which are supposedly better lube at lower quantities. But I read somewhere that the Ester oils are not miscible in methanol, but will mix with gas. So, the trick is to have a way to get the newer gas lubes mix with methanol, maybe a mixture of Ester and PAG's? But I am only re-stating what others have said, I am not qualified in this subject.

That is oil performance comparing similar gas engines. So, the bearing type in the conrod is the same. But the point is that there could be some improvements in oils used in methanol fuel?

Last edited by hsukaria; 12-02-2013 at 02:24 PM.
Old 12-02-2013, 03:50 PM
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Ok fellow "tweekers" I am searching for info..... I have an old FA-.65 that is in need of a new crankshaft !! The problem is horizions site lists 2. One long and one short... Can anyone tell me what the length of either one is. I would like to get the same one that I have, but i'm not sure if the one I have is short or long.
Thanks. John.
Old 12-02-2013, 05:16 PM
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Originally Posted by johnfly
Ok fellow "tweekers" I am searching for info..... I have an old FA-.65 that is in need of a new crankshaft !! The problem is horizions site lists 2. One long and one short... Can anyone tell me what the length of either one is. I would like to get the same one that I have, but i'm not sure if the one I have is short or long.
Thanks. John.
It's just the length of the prop shaft. They did the same thing W/the FA180, (there have been 2 conrod revisions in the FA180 engine also)
Generallt speaking, later revisions work in earlier engines. Choose whichever suits your appplication although the longer prop shaft can come in handy.
Old 12-02-2013, 05:25 PM
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Originally Posted by Jim Branaum
WAIT! I missed something.

I could have sworn that the reason gassers use ~ 5% or less oil was due to the use of needle bearings in the big end of the con rod.

Who suggested the lubricants used in gas mixes were better? I don't believe it! The ONLY benefit *I* see is that you CAN get synthetic lubes that will burn with the gas charge and I don't castor does.
The FG180 uses the same piston, ring & conrod as the FA180.
Some small gas versions have a bronze bushed big end. Other than that & the fact than the 180 bore muti-cylinder gas engines use the smaller 150 valves, there is no mechancal difference between "gas" Saito engines & glow versions.

The FG57T & FG84R3 use the same rods as the FA300T & FA450R3 couterparts.

The only difference between the FG & FA crankshafts is the pin that locates the prop hub/trigger magnet for the CDI on the gas version.
Old 12-02-2013, 05:35 PM
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I appreciate your reply Sr. I do understand that either will work! But IF I have the short one??? "if" ??? I don't want the long one! The short one is plenty long enough. The problem is that I don't know "how long" the short or long one is...... so that I can choose the one that fits my application. I have called HH and they didn't know either! But they are contacting saito to try and get an actual length of the respective cranks. I just thought I'd see if someone had ran into this before.
Old 12-02-2013, 05:44 PM
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Originally Posted by johnfly
I appreciate your reply Sr. I do understand that either will work! But IF I have the short one??? "if" ??? I don't want the long one! The short one is plenty long enough. The problem is that I don't know "how long" the short or long one is...... so that I can choose the one that fits my application. I have called HH and they didn't know either! But they are contacting saito to try and get an actual length of the respective cranks. I just thought I'd see if someone had ran into this before.

Yes, I ran into mysef on the FA180. What pitch prop do you have on it & how much thread is left after you screw down the OEM prop nut & washer on to it. Are you using a spinner adaptor nut? The dffference in length is in the threaded portion so a "long" shaft can be easily cut down in length, but a "short" shaft is kinda hard to lengthen.

A "short" shaft will barely have enough threads for an adaptor or lock nut. the "long" shaft will have some excess threads.

I can go up to my hanger room & measure the difference on my early & later model FA180, but that won't give you a direct value to compare. I can also measure the threaded portion of my FA91S that I bought new back in 1997. I'm pretty sure it would be a short "shaft" given its vintage. It should be the same length as an FA65.

Last edited by SrTelemaster150; 12-02-2013 at 05:51 PM.
Old 12-02-2013, 05:59 PM
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I appreciate the offer ! but I think I will just wait for HH to reply.............. Hope it doesn't take toooooooooo long...... I was running an apc 13x7 no spinner with a thick washer "same size as the prop hub", The regular nut, and an aluminum nut / locknut with big radius on end that I made. I suspect it's the long one? especially because it's 16.00$ more !!!
Old 12-02-2013, 06:51 PM
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The 91 has short and long shaft versions. You can't fit a backplate, prop, and two prop nuts on the short shaft.
Old 12-02-2013, 07:23 PM
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I have a question!

I am about to put together a bird that calls for a Saito 82 and all I have is a Saito 80 and I really don't want to get yet another engine this year (bought too many already!). What are the practical differences other than a couple 100 RPM?

Can I just use it or should I install the 91?
Old 12-02-2013, 08:40 PM
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82 has more power, but ther 91 is even better
Old 12-02-2013, 09:21 PM
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Originally Posted by bob62
82 has more power, but ther 91 is even better
I do love more power! But the 80 is a golden knight.... and looks so good just poking through the cowl
Old 12-03-2013, 04:55 AM
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So do real good lookin women mate,and you know how soon they can turn into a handbrake,apologies to all the women reading this.Pound for pound i'll back the 82 against all comers
Old 12-03-2013, 07:51 AM
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Originally Posted by Old Fart
So do real good lookin women mate,and you know how soon they can turn into a handbrake,apologies to all the women reading this.Pound for pound i'll back the 82 against all comers
O.F., I suspect that there aren't many (any?) women reading this post. Maybe once in a while one of the wives will snoop in to make sure we guys are behaving.

I can't wait to fly my plane with the 91S I just recently bought. That engine sure is a beaut. The 82a I have is also tremendous. But I don't have any experience with the 91S. I plan on putting a Turboheader muffler on it.
Old 12-03-2013, 01:11 PM
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Originally Posted by Old Fart
So do real good lookin women mate,and you know how soon they can turn into a handbrake,apologies to all the women reading this.Pound for pound i'll back the 82 against all comers

O.F. there is an important consideration you ignored. I ALREADY OWN the .80 and a 91.....

The only issue is do I build with the 80 or a 91...

Oh, your comments about looks really are...misplaced. Yeah, that is the right word. He who marries for looks always gets the short end of the deal after a few years. Choose wisely. And that is what I am trying to do with my engine selection.

OBTW, mine did not get worse looking so *I* am the winner!

Last edited by Jim Branaum; 12-03-2013 at 02:39 PM.
Old 12-03-2013, 05:40 PM
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Gotcha there old fart, I agree with Jim and I am on the second time around. On more important matters, I will watch what people do with these 62's, 82's etc. I have 1 of each, the 82 is going into a BUSA arf Fokker DV11, when I can get to it. If you are interested check out Steve Greens new rules for Red Bull racing. Interesting to say the least and an opening methinks for bright young sparks or old devious illegimate children.
Old 12-03-2013, 05:56 PM
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Originally Posted by Jim Branaum
I have a question!

I am about to put together a bird that calls for a Saito 82 and all I have is a Saito 80 and I really don't want to get yet another engine this year (bought too many already!). What are the practical differences other than a couple 100 RPM?

Can I just use it or should I install the 91?
Well, you did not mention what plane you will be putting this engine into.
Old 12-03-2013, 08:45 PM
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Originally Posted by hsukaria
Well, you did not mention what plane you will be putting this engine into.
Pawnee 40 if I can figure out where I put the instructions...
Old 12-04-2013, 05:05 AM
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Default Saito FA-91S

I have ordered the parts I need to rebuild my Saito FA-91. This will be a 1st. It will be fun. Wish me LUCK.
Old 12-04-2013, 06:57 AM
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Originally Posted by Jim Branaum
Pawnee 40 if I can figure out where I put the instructions...
If it is the 40-size, I would put the 80 in it and save the 91 for a bigger plane. But that is just me.
Old 12-04-2013, 04:37 PM
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I'm going to replace the bearings in my 90T the older one. I would like to get a gasket set before I start. Does anyone where I can get a set?

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