downunder-RCU

Well I can see why you might think the needle was sensitive if you're used to 30% nitro. You're probably using up fuel twice as fast as zero or low nitro which means the needle has to be opened a lot more. Plus nitro has a huge tolerance range between being too rich and lean which makes the needle less sensitive.

rsieminski

I worked on a spreadsheet today to help in the formulation, and cost effectiveness.
http://144.92.249.236/images/3154.xls

It should be pretty accurate, and maybe helpful.

Leaning out the idle screw a bit, seemed to hep with transition.

SDR-Hammer

Since I came across this topic a couple days ago I started doing a little research for mixing my own fuel. For those that haven't visited the Klotz web site yet, they have a printable ratio table for mixing glow fuel.
http://www.klotzlube.com/products/rc...ing_chart.html

It took some cross-referencing but I was able to match what you guys are calling KL-100 and KL-200 with the names in the Klotz table

KL-100 = Super Techniplate (20% castor blend)
KL-200 = Techniplate

Capgains

My Feedback: (4)

Hey rsieminski,

Great analyzer. I copied it to my documents for personal use.

Going back through your posts, I noticed that you are trying to run with less/no nitro. What kind of engine are you using and why are you trying to do that?

Dan

rsieminski

Dan,
I have an os .15la, mag xls .25, os .32sx, mag xls .40, th .46, and a brand spankin new mag xls .91. I didn't want to spend the extra $ to buy 30% any more, so I switched to 15%. On the .32sx, flights went from 6 min to at least 9 min ( I never pushed it, could have been longer). I tried 10%, and flight time went to 12 min, full tank, to empty dead stick ( don't ask ). The difference was hardly noticeable in the air, especially when I removed the head shims. Low/no nitro can tolerate higher compression.
The mix I made was 2.5% nitro, and other than having to lean out both needles ( the need to adjust the low needle was not real apparent at first ). Otherwise, 14 min plus, easy. I didn't clock it, but it seemed just as fast.
The major advantages were: Little difference in RPM, 1st quality ingredients, way lower cost, longer flight times, and I did it myself.
--Rick

The .32 was outrunning the .46fx's when we were playing chase, just as it did before.

Capgains

My Feedback: (4)

Ohhhh!!! never thought of that. I usually run 10 or 15%, but just recently started running 20% in my YS. I guess it does drink it down a little faster.

I once tried to run FAI 0% in my OS 46sf and it ran like....... well it didn't run well at all. It got really hot too.

So you are saying that you have to lean it up compared to a higher nitro then? It seems that the highter in nitro you go, the less important the needle valve is.


Dan

rsieminski

Well, it's not really running lean. The needle valve needs to be screwed in further. FAI 0% I think has 20% all castor. That shouldn't make it run hotter, cooler I would think. Nitro adds oxygen to the mix, so more fuel can be burned in the same amt of time.

YS have to fun the expensive fuel. I don't know why, but all the guys run 20% min. They say any less and it just wont perform.

Yes the needle seems to be critical on low nitro. Just a click or two off of peak, and it's ready to go. I had to completely readjust all the settings on all the engines. But, now they run just as well, even cooler than before, and only a few hundred rpm less.

downunder-RCU

rsieminski....maybe we should team up and spread the word that nitro is a waste of money, even when it's as cheap as it seems to be in America

But to put things straight about why an engine flies longer with low or zero nitro, it's all to do with the fuel/air ratio difference between methanol and nitro (plus the fact that nitro releases extra oxygen). So let's start by talking about your car burning gas (or petrol as it's called in the real world ). For best power it needs to be about 12.5:1 (that means 12.5 pounds of air for every 1 pound of petrol burned). Now fill the tank with methanol and you'll have to double the size of the carb jets because methanol needs a ratio of about 6.5:1 which means you need nearly twice the weight (and fuel flow) for it to burn properly. So your car that used to give 20mpg now does 10mpg. However, methanol will work with a ratio anywhere between 6.5 and 4.5:1 so you could be down around 7mpg!

Now let's go to model engines. Nitro needs a ratio of 2.5:1 which puts it somewhere around twice the volume needed for methanol (I'm saying volume but in fact it's weight). But this 2.5:1 is the LEANEST mix it will burn properly at. It will burn just as well 5 times richer or even more! Imagine a fuel/air ratio of 0.5:1 compared to methanol at even 4.5? That's 9 times more weight of nitro than methanol. Of course, when you mix the two then you have different air/fuel requirements depending on what % nitro is added.

This probably sounds a bit confusing but I can't think of an easier way to explain it. But as rsieminski pointed out, you're not really running leaner when you drop the nitro content...all you're doing is adjusting the flow of fuel to get the correct air/fuel ratio.

Dave Harmon

SDR....be careful with that table you got off the KLOTZ site. I noticed that they have some errors on the % vs ounces calculations.
I mean that for a certain %, they are showing the incorrect quantity in ounces. The table is fine to use....after you correct it!
Dave

Dave Harmon

Here is my experiences re % of oil & nitro vs engine mfg....
oil nitro
K&B/Veco .61 20 15 minimum for good transition & idle
K&B .40 " " " " " "
K&B Sportster .61 does not matter what you use it still won't run
Cox .049/.051 25 castor only, 30 nitro same as Cox fuel
Fox .35 no bearings 29 5 same as 'Dukes Fuel' good perf
Rossi .60 17 5 screams on this, lousy on zero nitro
Rossi .40 18 5 " " "
OS .32 helicopter 24 30 Klotz HeliGlow good rich run & trans
YS .61 20 20
YS .45 20 20
YS .120 all 20 20
YS .140FZ 20 20
YS .140L 24 30 Klotz HeliGlow/CoolPower Heli 30%
YS DZ 24 30 " "

Different engines require different fuel....especially all YS engines.
The closed loop fuel system of the YS models require the viscosity and nitro content to be in a range which will fit into the calibration window of the carburetor and regulator or else they are difficult or impossible to adjust properly. The above percentages are an absolute minimum for reliable operation except the 140L will run ok on 20x20 also. The YS engines are high performance therefore cost is ignored for maximum power and reliability. Power never ever came cheap and I don't expect it ever will, however, the cost of the nitro can be minimized by buying in larger quantity. I pay $40 for 1 gallon....$27 for 5 gallons...so I buy 10 gallons just in case the guy changes his mind next time!
Glow plugs are K&B1L idle bar for the K&B engines.
Rossi engines use Rossi #4 or #5.
OS .32 uses OS#8.
YS 2 strokes use Enya #3 or HobbyShack Performance #3 (only)
YS 4 strokes use OS F only.

Downunder said...

>This probably sounds a bit confusing but I can't think of an easier way to explain it. But as rsieminski pointed out, you're not really running leaner when you drop the nitro content...all you're doing is adjusting the flow of fuel to get the correct air/fuel ratio.<

True, however, there ain't no free lunch here.....natch, with zero nitro there is much less power (rpm) so there is a tendency to set the needle valve too lean causing overheating and I suspect the added sensitivity of the NV may cause a lean run in the air, even if the tank is properly located.
When I started flying Pattern 17 years ago, the engine to use was the Rossi 60 RE with in flight needle adjustment. They ran really good, however, I tried to use zero nitro and was melting the exhaust system. This was due to the sensitivity of the needle and was requiring resetting the needle in flight. Adding just 5% nitro completely fixed everything. Iv'e never actually seen ANYONE use FAI fuel (no nitro) successfully on any engine. This is not to say that it is not being done in Europe or elsewhere but if it is, I suspect the user is accepting operational problems as an offset to the high cost of nitro outside the USA.

Rick....what you might try with your engines is to run them on zero nitro and see what happens, then start adding nitro until they operate correctly. I see that you used 2.5% so I assume that you like it there. If the NV is too sensitive, add some more nitro and keep doing that till it works. You are using a wide range of engines so the oil & nitro content will probably be different. Generally, if you have the proper plug (I like hot plugs) there will be little or no change in rpm if you remove the glodriver at idle.
If it slows down the plug is too cold or there is too much oil, assuming the idle mixture is set correctly. Generally, for sport 2 & 4 strokes, 17% oil is a good place to start.
Never use castor in any fuel with todays engines. Above, I mentioned straight castor with the Fox .35. That is because there is no bearings on the shaft and they are set up very loose. They also have a different type of lapped piston/sleeve setup and all this really requires a very thick fuel to seal up everything. They run very well when used this way. For those of you that are using Klotz KL 100, castor oil just ain't needed and WILL carbon up your engine and the castor will crud up everything that gets hot...this is double true on 4 strokes. The exhaust valve and exhaust system will actually plug up to the point that the engine performance will suffer drastically...believe it!

Regards to All
Dave

DerFly

I wonder what the guys that fly FAI Pylon and FAI Control Line Speed are doing wrong?

rsieminski

The lower the nitro, the cooler the engine will run. If the engines on no nitro were melting some component on the engine, than the NV was set wrong, or there was too little oil in the mix. There is no mystery, synthetics will burn up way before castor will. Yes it may cause a litle more gum, than the synthetics, but break them down and clean them once a year(like you should any high performance engine), and they'll last years. Castor makes engines run cooler, by spuwing that oil all over the plane. That's what carries away the heat. Methanol has almost twice the latent heat of evaporation. This means it will carry away with it more heat than a higher mix of nitro, net resut is that it runs cooler. You can regain back most of those 2 or 300 rpm, by increasing the compression ratio. The pylon racere use only no-nitro/castor fuel. They avg over 130 mph. A little nitro gives you some slack with the NV, but it's not really necessary.

rsieminski

I speak only about the racers at my club, I don't know elsewhere. I also got to thinking, the hot or hotter glow plugs, combined with high nitro compound the problem of heat. Low nitro/hot plug, high nitro/cooler plug.
I was talking to the sprint car mechanic, last week when I got my methanol. I asked him about getting nitromethane, he said, very simply "most clubs don't allow it and the cars run hot, so we don't carry it". He did point me in the direction of the guys who do carry it, though.

Dave Harmon

Derfly..pylon race engines use pressure fuel tanks ( not exaust pressure) so the needle stays constant. Irrelevant for this discussion.

Rick...run what you like, say what you like, but what I said is true.
In my comment about glowplugs I was refering to proper idle.
Sprint cars don't use nitro...he was probably refering to the sprint car club.

DerFly

Touché!

Ed Smith

Lets just clarify some of the Pylon Racing stuff we are reading here.

Most pylon racing circuits in North America use 15% fuel usualy supplied by the contest. A.M.A. rules.

The international event FAI-F3D rules stipulate 20% castor (Not synthetic) 80% alcohol. This has nothing to do with care of the engine. It has everything to to with the availability of nitro and synthetics in some of the countries. F3D engines are a .40 size engine for use with tuned pipes. RPM on the ground is 28k+.

Pylon racers do not use pressure tanks. The pressure is taken from the muffler or the tuned pipe. The tank used is the Tettra tank. This tank has an internal bladder the same size as the outer plastic tank. The bladder exerts no pressure due to its being stretched, it is not stretched. The fuel feed goes into the bladder while the exhaust pressure goes between the bladder and the tank. To fuel these tanks all of the air is sucked out of the bladder, fuel is then pushed in. This results in a solid cell of fuel always at the feed tube. The engine never goes lean because of air in the line. There is no air in the line. Whatever you set the needle at is what you get, right or wrong.

There is no reason why this type of tank should not be used for sport flying. It would solve a lot of the "Why does my engine go lean" questions asked on this Forum.

Ed S

TM3

My Feedback: (2)

Here is what I run in my engines.

St3250 no nitro, 5% klotz, $2.80/gallon

ST2300, ST90, ST45. OS46FX
NO nitro, 13% koltz $4.70/gallon

I get the same if not more power with no nitro.

ex. ST2300 with Jett Stream muffler, 16X8 APC prop
no nitro, 13% oil, 9850rpm
5% nitro 20% oil , 9,700 rpm
10% nitro, 20% oil, 9700rpm

No nitro means longer run time
No nitro means less fuel cost
No Nitro means more power
No Nitro means a cooler running engine

downunder-RCU

Dave...I have to wonder if you've ever actually tried using no nitro or seen anyone use it. I've been using zero nitro for something like 40+ years in every engine I've owned, both CL and RC, and I've NEVER experienced any problems whatsoever with starting, idling, power, needle sensitivity...you name it. And my standard fuel is 20% all castor which is basically FAI fuel except I use a squirt of Armorall which would make it illegal for FAI pylon or CL speed.

The reason for FAI fuel in competition is to take fuel out of the equation when comparing performance in pylon and CL speed. Castor is chosen because it's know to be able to provide all the protection needed in such extreme performance. A CL speed engine is by far the highest performance engine in the world, bar none. AFAIK Castol M is the only proprietary castor that can be used...I'm not sure if Bakers AA meets the requirements. Klotz certainly doesn't. In competition the fuel must be supplied by the organisers to avoid any cheating.

Dave Harmon

Down...I wonder what type engines you are using? I know you are not using YS anything because they will not run on FAI fuel!
It's been awhile...a long while...since I tried to use FAI on any of the engines I use. I tried FAI fuel on the Rossi 60RE and Webra 60RE and it just won't work for the kind of flying I do. It might be ok just to tool around but engine operational problems aside, I need the much greater torque that the nitro provides for long vertical uplines with a 12 pound plane. As an example, I am using a YS 140L with an APC 16x12 and with 20% nitro, the engine will lose considerable rpm on an upline but stays constant with 30% or more nitro. Under certain conditions I have used 50% nitro to get the performance I need to fly certain maneuvers. I suspect the reason the engine loses rpm is due to the decreasing airspeed on the upline which would reduce the ram air effect on the prop which would increase the load on the engine. Adding nitro on these engines DOES NOT increase the rpm very much...it considerably increases the torque which prevents the engine from slowing down once it reaches a rpm that is set by the throttle stick.
Again, I am not interested in turning more rpm, only in not losing rpm.

I am beginning to think we are all talking more less the same thing except the type of engine and it's application.

I have absolutely no concern or regard for the cost of this fuel.
Whatever it takes to get the performance I want is what I will spend. Why would I spend $670 on an engine then try to run it on a fuel that will not extract the maximum performance? It just doesn't make any sense! A gallon of the fuel that I use costs $15.87, that's Klotz HeliGlow 24%, 30% nitro & balance alky.
I burn 18 oz per flight...that's $2.23 per flight. Cheap for the performance I am getting. There are many, many pattern fliers out there (USA) that are not interested for whatever reason in mixing this type of fuel...they would rather pay $22 gallon for CoolPower Heli 30 to get the same performance as I do. Their cost per flight with an 18 oz tank is $3.09. Mixing my own fuel can be a competitive advantage..as an example, these engines are greatly affected by high altitude, heat and humidity. The guys using 20x20 are staggering through the air while the guys with CP 30 are doing ok but I just drag out a bottle of 50>60% and blast past them with the same performance as I always get when the weather is normal.
Am I going overboard?....maybe...but there is no use going to a contest and having engine problems whether it be operational problems or lack of power.

As I said previously, I have never seen FAI fuel used without problems....and I don't know anyone who would waste time with it. I know nitro is hard to get at any price in Oz but it is easy here
and that probably has a lot to do with both of our experiences.

Is there anything different you do to make your engines run correctly on FAI? What kind of engines? Tank placement, header tank, type of pressure etc. carb insert??

Dave

downunder-RCU

Dave...I think now we can see why the difference in opinion. You're looking at it from the side of no expense spared maximum performance for competitions and I'm looking at it from the average sport flyer's side.

From my viewpoint going on what you say about YS (and I've heard it before so I've no reason to doubt it) one of those engines would be totally useless for me. The majority of flyers (99%?) don't have those concerns and I'd even say that if a sport flyer felt he needed nitro to have enough power for his model then it needs a bigger engine.

As for what engines I use FAI fuel in...Rossi 45, Enya 60X and 80X, OS 80, SC 1.08 and for CL I use OS 40VF (piped), Irvine 40RLS (piped), ST 51 and Stalker PRO61RE. All of these engines will start first flick (yes, we hand start 60's at full throttle ) and tuning is dead easy. Admittedly I'm so familiar with tuning them that maybe if I tried running 20 or 30% nitro I might think the engine didn't respond to the needle. But even so, if someone can't tune an engine on FAI fuel then I'd suggest they take off the boxing gloves

All my engines are out of the box standard except for the Enya 60X which I've raised the compression to 13.5:1 to take advantage of the extra compression that FAI fuel allows. It now has the same power as the 80X.

flyingcubby

My Feedback: (35)

TM3...Whats your fuel recipe for the big super tigers.....Mike

TM3

My Feedback: (2)

On my ST3250 and ST2500 I run no nitro and 5% klotz synsthetic.

I have found that using any amount of nitro in ST2500's, 3250's, 4500's will cause a flame-out a couple of minutes into the flight from overheating, even with 18% oil.

With no nitro the engines run cooler allowing the use of less oil.

On my ST2300's I have been running 0% nitro and 13% oil, they run great and poduce more power than with nitro. (I believe because of less oil)

I have over 90 hours on a ST2300 (two seasons of use) with a tuned pipe. This fall I will install a new ring and hone the cylinder and it should be good for two more years. Cost $16

Next spring I am going to start a test on the ST2300.
0% nitro, 5% oil and will check for wear next fall. This should push the power even higher.

Also, those who have problems with a lack of fuel flow, lean running, using no nitro will richen the mixture.

Joaquin

My Feedback: (3)

I read from you in another thread about using Mobil Jet Oil II and and it seems to me very interesting.

I live in a small town Pachuca near Mexico City at an altitude of 8200 ft ASL, as you can imagine the performance we get from the engines is very poor about 70 to 75% from sea level, also is not easy to get different kind of fuels the Hobby stores only import the most common ones for motors like OS46FX.

For this reasons I started to do my own brews and I all ready buy a case of 24 Quarts of Mobil Jet Oil 254 that is the third generation of Mobil Jet Oil, basically same ester oil but with some advantages in the formulation package.

I'm looking for maximum performance on ringed motors like YS-80 Helli, OS 91FX, Moki 1.8, OS 160FX, 3M140 Mintor, I normally adjust the amount of oil and nitro for each one based on the manufacturer info.

My questions are:

Would you go straight Mobil Jet and add maybe 2% more or maybe a blend like 80% ester 20% Castor?

The main criteria to see if I'm in the right track would be the temperature of the head vs RPM'S?

Ed Smith

More Nitro, Less power eh. I guess the drag racers have got it all wrong!!

Ed S

Capgains

My Feedback: (4)

I have to agree with you there Ed. I don't see how it could provide less power. I have a feeling however that there comes a point in the mixing where adding more nitro won't necessarily add more power. I'm not sure where the breakpoint is.
To me running a higher nitro (20%-30%) doesn't seem to give more power, but it sure makes tuning easy.
I though someone told me once that boat guys use 40%-60%. Who needs a needle valve??


Dan