downunder

There's been some glowing pictures painted about the American free enterprise system (which is the same as we have in Oz anyway) but on the other side of the coin one company in America was short changing on the amount of fuel sold. Quite accidentally because there was a fault in their dispensing machine and it was fixed as soon as they were notified of the problem. At least one company mixes by weight so you get short changed on both nitro and oil (this was proved by doing an evaporation test on that fuel). At other times fuel has been delivered with no oil in it whatsoever.

Nitro is very expensive here in Oz so it's wise to think twice before using it. Other than getting a bit more power from the engine there's no other reason to use it. The next size up engine will give the same power but run perfectly on much cheaper zero nitro fuel. If you make your on fuel then it's not only cheaper but you know what's in it. I'd guess it takes me less than 10 minutes to knock up 5 litres of fuel out of bulk.

CL speed isn't a good example of why nitro is necessary. The world record in FAI speed where nitro is not allowed is 335Km/hour using a 2.5cc (.15) engine. The word record using a 10cc (.60) and nitro is allowed is only 10Km/hour faster. Just for interest's sake, the record using a pulse jet is about 395 Km/Hr

loughbd

Can you say urban legend?? That foolishness about short filled bottles and no oil has been kicking around for years. Funny how it was never mentioned in any of the major modeling magazines od by any of the major hobby distributors.

I think you better check your info on C/L word records again.

Byron mixes by weight and everyone knows it so no one is being cheated.

sigrun

The answer to that is straightforward. There is no resistance against using it because nitro is "as cheap as chips" (as chips used to be in the good old days before McFries et al turned them into greasy gold) in the US (compared to places like Australia), AND marketing reinforced by availability aided by the belief that nitro = xTtrEme performance exacerbated by the natural human inclination to equate more = better.

As for no-one mixing their own fuel, you wouldn't bother either (nor would I) if you could buy pre-mix in any flavour you wanted for the prices they do. Ever been to the U.S.? An obsessive consumer's heaven.

However, to counterbalance the anti-nitro argument that Dar Zeelon invariably always puts forward that I don't agree with - which is kind of unusual and surprising as he's usually pretty level headed with the exception of his consistent zeal, nay almost phobic hatred of the stuff - (Hi Dar ) the addition of nitro in certain engines can add power, namely torque which is significant and noticable when the engine/prop is under load. eg: Verticals. Go to a bigger engine I hear you say? More weight, etc.

The bottom line is most people simply msunderstand how nitro works, when its use is viable and where the % benefit factor cutoff lies. If I can quote fromt he Bolly book if you aren't inclined to believe me. The significant paragraph is the second. That's where most people just don't get it when they add nitro and it either doesn't re-tach spectacularly or they can't perceive any significant speed or acceleratitive increase putting around with their latest ARF sportster.

Nitro is a power enhancer as it increases the amount of oxygen available in the fuel for combustion. The down side is that it generates more heat (often needs a lower combustion ratio) and can contribute to rusting of the engine (caused by the acidic by-products of the combustion). The use of small amounts of nitro will help most engine run smoother.

Nitro methane will not increase rpm, but as it’s combustion produces more energy, the engine will develop more torque, allowing the use of bigger propellers, or better operation under high loads. A classic example of this is R/C aerobatics where adding nitro to the fuel will give a big performance increase in vertical climbs.

Me, I'm a two stroke fan and I like to go sustained vertical for big pattern manouvres so I love the stuff. I'd use an even a higher percentile if it wasn't so expensive. OTOH, I woudln't use it for puttering around the circuit instructing, as it'd be burning cash for no appreciable or worthwhile benefit. Bottom line is don't use it if what you're doing won't benefit from the addition, but to discern that, you have to understand what it does and how it works so you can triage that decision.

Now heading of on a completely different tangent, Motul Micro is a superb R/C synthetic oil, but like ELF, are Euro brands not marketed well here, expensive and quite difficult to obtain. Klotz Techniplate and particularly CoolPower are, with the latter having achieved and semi-mythological superiority status demanding you buy it or be perceived as a lesser being. A bigger problem is easily obtaining quality castor. (Hi Brian [X(])

DarZeelon

Sigrun,


I am very consistent in what I say.

I am not anti-nitro. I just say there is absolutely no reason to use any more nitro than necessary, in any engine that does not need it.

My own experience and that of my customers says the following:

By adding an extra head-shim to the MVVS .49, you may use 15% nitro.
The RPM gain is about 100. The added cost is 20% more fuel that costs 20-25% more per gallon...

Paying 42-47% more per flight is not justified by an RPM gain of 100. Period!

There is absolutely no improvement in reliability (as this engine becomes dead reliable after a few hours with just 5% nitro), or in throttle response and transition, from using 15% nitro.

It doesn't even run more smoothly than with 5% nitro...

So, what are you paying so much for?


But, a YS engine will run badly on low nitro. For this engine type more nitro is a bare necessity.
If I had a YS, I would not try to run it on 5% nitro.

This is where nitro is necessary and using more of it is not a waste.


As to people who put a .61-.91 engine in their .40 size 3-D bird; do you think it will fly better with this brick up front???

Nitro is supposed to increase (?) RPM on same-size props, in addition to allowing the engine to spin a larger prop at the same RPM...

...

That OS (USA) web site that Brian so exuberantly dismisses, says that castor oil is recommended for ABN engines and that all-synthetic lubricant fuels cause all kinds of problems...

...Who would I be to dismiss this claim?...

sigrun

Hi DZ

No argument. As much as anyone subject to he human condition can be.

Well, life's about perceptions, and I'll bet you've got more people than just me fooled.

What you're most clearly not is its advocate and the zeal and vehemence with which you consistently attack its use certainly gives the impression you consider it generally an expensive placebo.

Didn't I just say that? [sm=spinnyeyes.gif] We're on the same wavelength there. [sm=thumbup.gif]

Did you even read what I wrote about the irrelevance of taching as a measure of gauging nitro's worth? [sm=disappointed.gif]

Nitro assists smooth transition and stable idle. I consider that a known, and won't debate it even should you choose to disagree though I think you do concur if I interpret you correctly? That more nitro than necessary to achieve this somehow makes it even better is as false a rational as saying addition of nitro makes no difference at all. Improving transition or idle by increasing nitro to high percentiles is not a valid reason to add more nitro, but then, I don't think anyone claimed it was ..did they?

...
I just said that. We're agreed on that point. But let's clarify that adding nitro does make a difference versus no nitro.

The improved sustained vertical performance I referred to in my earlier post which you can see if you care to experiement for yourself, and Les Bollenhagen corroberates.

This is kinda' out of left field. Don't know where you picked up this tangent, but I'm not an advocate of more weight (higher wing loading) = better aerobatic performance. Nor do I applaud the American penchant for fitting the biggest capacity engine that'll fit in the space available. That's why I use nitro instead. Perhaps you confused my "use a bigger engine?" posed as a questioning statement intended to imply it absurd as being advocacy of same? A problem of the written word without inflection.

Nitro methane will not increase rpm, but as it’s combustion produces more energy, the engine will develop more torque, allowing the use of bigger propellers, or better operation under high loads. A classic example of this is R/C aerobatics where adding nitro to the fuel will give a big performance increase in vertical climbs.

With respect, I think you need to re-read what Les B said, which doesn't imply what you are suggesting according to any conventions of comprehension with which I am familiar.

Note that unassuming clause "better operation under high loads". What Les means by this and what you'll find is that as the prop loads up in a pure thrust versus weight 180 degree vectorially opposed resolution with vertical ascent, the tendency of the engine's ability to sustain that thrust is improved such that RPM is slower to deteriorate contributing to longer and superior sustained climb. In a two stroke, it's most pronounced. Torque, admittedly at a price, but without compromising for either weight in a bigger two stroke engine or weighty four stroke clunker, nor outrageous (in this country) captital outlay for super high performance engine like YS - which demand you use even higher nitro percentages in your fuel anyway.

Really, I don't know what all the fuss is about. If you believe it's of no benefit to you or doesn't represent value then it's simple - Don't use it! [sm=RAINFRO.gif]

To me, the benefit I derive in terms of the objectives required within my preferred flight envelope from the addition of nitro is, and I will. So everybody should be happy isn't that right? [sm=sunsmiley.gif]

DarZeelon

Sigrun,


The example I brought up was the MVVS .49.
I am sure some other engines may behave better with more nitro, but not this MVVS.

Since getting some ingredients here is expensive/prohibited, the more common way is buying commercial fuel, to which I always add castor oil, for a 20% oil balance.

I have not tried 0% nitro in about 20 years, so I cannot tell you if this example engine would run more roughly on FAI fuel, but MVVS do recommend this. So I do strongly advocate 5% nitro in the fuel.

...And this should be perceived as not 'against nitro', just against too much of it.
For most engines out there 15% is too much...
But at the same time, 0% may be too little, from a running consistency standpoint.
When the glow engines began to become popular, they were run on a mix of castor oil and methanol, if I recall correctly.


And...most non-professional fliers do use more nitro, seeking higher RPM; rather than trying to get more torque, at the same RPM, to spin a bigger brop for more thrust... Les Bollenhagen is a professional.

sigrun

When we were kids, we used to run our glow engines on no nitro. But they were loop scavenged, weren't seeking sustained verticals in C/L that one wants in R/C aeros, and far more conservatively timed which lent itself to more consistent torque throughout consecutive manoeuvre, such as power curves upper mid-range in a small capacity single cylinder loop scavenged two stroke might be called torque. At the very end of that time, we did start using nitro in low percentages, and I can only say I wish we'd had it earlier if only for the sake of ease of starting and tuning the needle.

Regrettably, this is too true. At a club level one either encounters the "don't need no stinkin' nitro" attitude born of ignorance opposed by the "can't have to much nitro", "more nitro Lester!" crowd who think it's gonna' make 'em go proportionately faster. They can both be readily identified by a conventional diameter for engine capacity blade and the pitch of their props. No matter the engine, model or intended flight envelope, it'll always be fitted with the ubiquitious one size fits all 6" pitch! The former arre usually best friends with the "real men use ALL castor" folk versus "the CoolPower rulZ" crew hangin' with the latter, eaching thinking the other donkeys. [sm=spinnyeyes.gif]

But on topic. I have an 8 year old but NIB and unused O.S. 46FX. It will be interesting to see how its P&L fares. I was going to sell it and replace it with something known fault free, but have decided to pander to my curiosity, which I fear I'll regret. But what the heck, it's only money. I'll keep a log. Gonna' run it for the first litre on 100% degummed castor at 20% by volume and 3% nitro, then I'll change to my standard AXX Schnuerled sport 2 stroke summer brew of 20% oil by volume at 4:1 Klotz Techniplate : AA castor and 10% nitro. It was purchased around the time, or 6 months after, the ABN liner fiasco was occurring locally when O.S. and the local distributor were still in a formal state of refutation and denial. My mate had one at the time (bought earlier than mine) which peeled the liner within a couple of hours use. Literally. I didn't believe him at the time and considered he must have done something to cause it. Couldn't believe the sight we encountered when we disassembled that engine. He got nowhere with warranty inquiry and just put it on the shelf in disgust. We all now know the cause. Man was that engine screwed, in zip operational time, and though no fault of his other than to purchase and run it.

dove57

Well seems my small request sure stirred the pot some[&:]

Sirgun

your comments taken aboard thanks I don't think it was "just" a fluke story about your buddy's
FX either despite what some say on this topic....."there was only a few of these bad batches" ....blah,,blah,,,
thing is this IS a concern about the FX & god forbid I hope it doesn't continue on the AX[X(]



I've got one "oil" question for you .......I've 2 FX's both histories "unkown" as far as what type of fuels
that were run through them & "if" they were properly broken in.........from new,
so what "oil" type & mix percents should I use on them now???[]


**Ps The "Nitro" debate was interesting, from all sides .........me I'd be using 5%,
the right amount for Sport flying , my opinion

dove57

Lough

I think D-U is right - on the money about CL & the "nitro" use in different classes,
not sure about the current (mph) figures........but they wouldn't be far off the mark

DarZeelon

Sigrun,


I would say, why play against notoriety? The FX was known for peeling, so why not let someone else deal with this problem?
To get the P+L replaced by OS, should it fail...


I had a .46FX from about the same era; maybe a bit later, which did not peel its sleeve, in about 35-40 hours, until I sold it.
And it lasted, maybe because I always fed it 20% oil, half of which was castor. Or, maybe I was just lucky...
Maybe it was ABL already... I am sure it was not. Anyway, I received no complaints from the buyer.

The FP that I had previous was not so lucky... It peeled badly, but was able to continue running, for over 20 hours, after peeling about 1/3 of its sleeve... I didn't know better then and fed it 'CruelPower' 5%...


As to props, I have a customer using the MVVS .91 with the tuned silencer in his 4.5 kg Hanno Prettner Tiporare.
The .91 is not an RPM paragon and so, I recommended that he use an APC 13x10 prop.

It accelerates very rapidly and flies FAST! But it sounds like it is cruising at part throttle... This is what high pitch can do for you.
It even climbs the up-lines in the pattern quite well.

loughbd

BS flows like the Mississippi in this thread.

I HIGHLY recommend you guys get a copy of Clarence Lee's book, "the R/C Engine volume three" and Dave Gierke's book, Two Stroke Glow Engines".

Both have excellent descriptions on how and why Nitromethane works and as both are known authorities (rather than self claimed experts) in the field unlike most of the unknowns here, are much more believable.

downunder

Then this urban legend (short fill) has been perpetuated right here in RCU at http://www.rcuniverse.com/forum/m_3155915/tm.htm

From the official FAI web page for model aircraft world records.
2.5cc 335km/h Paul Eisner (UK) 13/10/2001
See the video of the actual flight at http://www.flyrc.org.uk/record/control_line.htm and listen to what a tuned pipe should sound like

5.0cc 312km/h P. Halman (UK) 12/10/1986
10cc 345km/h Ken Morrissey (UK) 25/08/2003
Reaction motor 395.64 km/h Leonid LIPINSKI (USSR) 06/12/1971
[/quote]

loughbd

RCU is not what I would call a major R/C publication and as for believing what is written on it, just look at this thread alone. There is more misinformation spread in these forums than all of the rest of the hobby put together.

NM2K

My Feedback: (14)

---------------


IIRC, the Tiporare was designed by one of our own, Dick Hanson, not Hanno Prettner, of whom I am also a fan. (That'll drive the English majors nuts!). <G>

Dar, this is OT, but if you wouldn't mind, I would appreciate a recommended prop size. I bought a NIB MVVS .61 (4-bolt head) a short while back. I also bought a tuned pipe set up from the same fellow. Which prop would be best to start with in say a Seventies pattern ship? TIA

loughbd

Yup, I'd sure like to get my hands on one of those rare Tippos designed by Hanno Prettner. Must be the rare Israeli version as ours were all designed by Dick Hanson. At least the ones I sold at H Shack were.

sigrun

Eight years on, no chance of having the problem dealt with by our local O.S. distributor now. Take it to O.S. Japan before using it? Apart from "Catch 22" "How do you know it's gonna break if you haven''t broken it?", it'd be a three act play before triaging shipping etc. As for onselling the problem to someone else, I had considered it, but....label me an anachronism or even pious in that regard if you wish, but knowing what I do and given a high probability that it will suffer liner failure, that's arguably immoral. Some things are just more precious than money. I'd never make a very successful businessman.

I checked the pricing of genine replacement O.S. P&L on Tower....<shudder>..Bzzzzt that idea.

Even the better priced replacement ersatz ones from Just Engines which I suspect are Leos are on the pricey side after exchange and delivery. The ceramic sets Saturn used to sell are finished, so if it flakes, it's a writeoff.

Interestingly, I have a well used 40FP ABC, very late production. It's been a bull of an engine. Surprising longevity. Admittedly, zero to 3% nitro, run only on 20% castor throwing an 11 x 5 used purely for ab initio instructing all of its operating life. Decoke is the only maintenance call it's ever made. Still going strong. Mind you, it loks ungly covered n the black and brown goo, and regularly gets attacked with the aluminium safe oven cleaner.

I think that clause is significant. ie: Tuned pipe. On standard silenced smaller capacity (.46 class) engines, nitro really counts as per previous uplines mention.

Two strokes and fast using energy management are out of vogue in pattern now. Masking mediocrity with torque is in. I personally like 2 strokes with high pitch props and using energy management a la so well demonstrated by the inimitable Bob Hoover.

sigrun

I know of no oil which'll repair a damaged or worn engine or prevent failure of a defective component regardless of content. Given the FX's history, if it were me, I'd take the 20 minutes to strip 'em and inspect the P&L's to ascertain whether they're worn or damaged examples so you're working from a known. If the liner's plating is chipped and flaked, you can't miss it.

If they're OK, reassemble and run - or overhaul as required. ie: decoke if they've been run on castor and need one, and whilst the guts are out, it offers the opportunity to visually inspect the rear cage condition for rust and corrosion which is likely if they've been sitting unused for a while.

But to your oil question. For engines of the FX's class in that capacity, after rmuch experimentation, I've standardised for my use on a brew containing 20% oil by total volume in summer, and 18% oil by volume in winter. I choose to use a ratio of 4:1 synthetic to degummed castor respectively 16%/4% summer and 15%/3% winter. I prefer Klotz Techniplate synthetic from the readily sourced available options. That oil is a consumable which goes up in smoke and that Klotz is dearer than Cool Power should suggest something other that I'm poor at arithmetic or just like red coloured fuel. That's what I use in every .45 through .53 class Schnuerled ringless tapered piston composite construction liner engine in my hanger. ENYA, TT, O.S. ST (Italian), Irvine, et al. That's what I'd use in those FXs after inspection confirmed them undamaged if they were mine. I'm not a fan of CoolPower synthetic oil for sport use.

DarZeelon

Sorry, Dick Hanson, for not crediting you.

The original 'Curare' was, I believe, designed by Hanno Prettner. [link=http://www.rcstore.com/rs/general/listproducts5.asp?catid=41&catego=PL]Scroll down here[/link].

I did not know who [link=http://utopia.rcuniverse.com/rcarchive/70/2003/01/3/45836]made the change[/link].


Sigrun,


MVVS makes this .61-.91 tuned silencer.

It is not the full length tuned pipe.

speedster 1919

My Feedback: (3)

Hi Dove57 Theres always 2 things that have baffled me somewhat over the years and thats
why do our North American buddies love to use high amounts of Nitro in generally Sport enigines?
the other is very few seem to mix their own fuel?

I can understand everything there in the US is on mass.....you can get oodles of whatever you want,
would like to hear from the US guys on why they all use the over the counter fuel......
does mixing your own over there prove not cost effective?
IN answer to your question. Nitro is only produced in the USA in the whole world. It's all about price. Hobby shops have pre-mix at good prices and it isn't worth fooling around with mixing our own. Besides our EPA doesn't want average people playing with chemicals. Funny We have lots of foreign produced products we are buying up because they are cheaper than we can produce ,but in the long run we are buying ourselves out of jobs. More and more local hobby shops are closeing and mail order is getting bigger. The problem will be fuel that is not easily shipped and then you will see Americans mix more of their own fuels. I mix my own just for the fun of it.

loughbd

I don't mix fuel for the same reason I don't add octane to my gasoline. Why should I when it comes that way out of the pump. Why make fuel when you can drive to the local hobby shop and buy a gallon of exactly what you want and then go use it? Try to find nirtomethane, Castor oil and methanol in the average small or medium city. Unless there is a racing shop around you aren't going to find any of those ingredients. Then try to find wetting agents and all the other "secret" ingredients that come in commercial fuels.

The last time I bought fuel, I bought 50 gallons of 10% nitro with 20% oil fuel. Have you ever tried to lift a 55 gallon drum of methanol?

Commercial fuel is consistant batch to batch and it is cheaper than going out and buying all the ingredients.

Americans use excessive amounts of nitromethane?? I don't think so. Most of us use between 5 and 15% nitro which is not much. Why do we use it?? because your engine idles better and runs more consistantly. Some of us use it in large percentages for special events like control line racing events because it DOES increase power. Small 1/2 A engines love nitro. They are very small and give their heat off quickly. Nitro increases the heat and the little guys run infinitely better on fuel with 25 to 35% nitro.

I use 10% nitro which I don't really think is all that high. Why 10%? Because I worked for a major hobby company and their brand fuel was 10%. I got it for $6.25 per gallon. I couldn't make it for that price. We sold it for $35.90 for a 4 gallon case at the time. You couldn't make it for that. It was a "loss leader". We sold K&B500 for $12.99 a gallon and 125 four cycle fuel for $11.99 a gallon.

So. why do we all buy commercial fuel?? Because it's cheaper, easier, and less dangerous than making it ourselves.

decay

I think Ill just forget about that MVVS I was thinking about.
Get the monkey off my back, Im AMERICAN & PROUD!!!

downunder

Because here in Australia I can't be certain that what they sell has 20% oil (castor/jet oil blend), a dash of Armorall, zero nitro and 3%acetone. For a couple of engines I need 25% oil blend or all castor. Apparently if I lived in America I could get that off the shelf

DarZeelon

Dennis,


Baker's AA castor oil is made in USA.
Klotz BeNOL castor oil is made in USA.

So are Fox and K&B engines, but not MVVS and not OS...


That monkey is thinking... what is good for your engine, but he never was on your back.

Ernie Misner

We have one good hobby shop here in the city where I live in the USA. Interestingly I can NOT even buy 5% nitro fuel. All they sell is 10 and 15%, which is too bad because I would purchase the 5% for my ST G90 if I could.

Ernie

XJet

Yeah, homebrewing fuel is not hard and (around here) saves us a heap.

A member at our club bought 4ltrs (about a US gallon) of 10% fuel and it cost him NZ$70. I mix my own and it costs just NZ$26 to make exactly the same blend.

Then there's the fact that I run a wide range of different engines and they all thrive best on slightly different fuels.

My plain-bearing engines get at least 10% castor, 10% synth oil, 5% nitro and 75% methanol

My 4-strokes get 4% castor, 16% synth, 10% nitro and 70% methanol

My 2-strokes get 4% castor, 16% synth, 5% nitro and 75% methanol

And, when I get around to buying a larger SuperTigre, I'll have to mix up some low-nitro fuel with 12% oil in it.

No problems for us do it yourselfers :-)