quote:

ORIGINAL: DarZeelon

So you see, Hugh?

I did not even know the K&B-4C and the Thunderbolt FS plugs existed...


This is interesting stuff!

quote:

ORIGINAL: FlyerBry

When running my Saito .82 on 30% what impressed me the most is not so much the increase in top RPM, but the increase in torque. The engine simply powers through climbs without slowing down on the 30% where with the 15% the engine makes good power but it eventually poops out on a straight-up climb. All I can say is the difference is quite noticable - enough that I will miss it when I switch back to 15%.

I have to also point out that the subject of this thread refers to the O.S. .70 FS. I have one of these as well and never even considered trying higher nitro content in this engine. It has never struck me as a powerhouse of an engine. It's greatest quality really is its reliablity. To run 30% in this engine is kind of like souping up a Honda Civic. I have never really gotten into that fad but to each his own!

quote:

ORIGINAL: DarZeelon

Paul,


There should be a way to put a limit on this...

Because methanol has a best power stoichiometric ratio of about 5:1 and nitro runs at 0.5:1 - 2.5:1, the more nitro you have in your fuel, the more fuel your engine will 'drink'...

Using 40% nitro, you use fuel at a rate ~2.5 times higher than if you run 0-5% nitro.
Using FAI fuel (0% nitro), you are already using fuel at a rate ~2.5 higher than gasoline (best power stoichiometric ratio of about 12.5:1).

Glow fuel with 0-5% nitro already costs 3 times as much as gasoline.

Even with no-to-low nitro, each and every one of us is paying 3 times 2.5, or 7.5 times more for fuel, than if he was running on gasoline. With 30% fuel costing over 3 times as much, each of us would be paying 22 times as much for fuel.

40% nitro fuel is currently not offered by Tower and I had trouble finding it elsewhere too, but it would bring the fuel cost up to over 30 times the equivalent gas cost...


Do we all want to make this hobby more affordable, or do we want to make R/C the the hobby equivalent of living in Beverly Hills, owning a private Learjet and a yacht and touring the whole universe, while earning a current median level salary?...

We don't all drive a 'top-fuel dragster' to work. In fact, none of us do.
Let us all regain our sanity...

quote:

ORIGINAL: RC-Bearings

This is a HOBBY. It is for your disposable income, not your food money. I am not telling anyone they HAVE to use 40% nitro fuel, only that it DOES work and works well with many engines. And I don't think there should be any limits placed on modelers.

quote:

ORIGINAL: RC-Bearings

quote:

ORIGINAL: FlyerBry

When running my Saito .82 on 30% what impressed me the most is not so much the increase in top RPM, but the increase in torque. The engine simply powers through climbs without slowing down on the 30% where with the 15% the engine makes good power but it eventually poops out on a straight-up climb. All I can say is the difference is quite noticable - enough that I will miss it when I switch back to 15%.

I have to also point out that the subject of this thread refers to the O.S. .70 FS. I have one of these as well and never even considered trying higher nitro content in this engine. It has never struck me as a powerhouse of an engine. It's greatest quality really is its reliablity. To run 30% in this engine is kind of like souping up a Honda Civic. I have never really gotten into that fad but to each his own!

Well, you did it with the Saito and look at the results! The OS will respond the same way.

quote:

ORIGINAL: DarZeelon

quote:

ORIGINAL: RC-Bearings

This is a HOBBY. It is for your disposable income, not your food money. I am not telling anyone they HAVE to use 40% nitro fuel, only that it DOES work and works well with many engines. And I don't think there should be any limits placed on modelers.

Yes, Paul. I agree it is a hobby and this is exactly the point.

Since it is just a hobby, we all have some sort of a budget dedicated to it.


If we use this budget to fly each weekend; say, making 5-6 ten minute flights on 5% nitro, we would enjoy ourselves very much.

If we would use 40% fuel instead, we would be using the same budget to finance 2-3 five minute flights each weekend.
And we would be replacing/overhauling our engines after half the time period.

And all we would gain is about 5% in flight speed and a better climb rate...


I think the second option would be way too short in duration, to make the enjoyment equivalent to the first option; even with that (obviously insignificant) 'adrenalin rush' from that added speed... After all, you're going just a bit faster, not twice as fast.


And... if you want the additional speed, you could have it at a small fraction of the additional flight hour cost, by just using (buying it in the first place) a slightly larger engine and high-pitch props, still using 5% nitro.

Your model will not know the difference, will fly just as fast and give you just as great an 'adrenalin rush', as the smaller engine would on 40% nitro.... And you will lose about 1 minute per flight, instead of cutting your total weekly flying time by 75%...


It is simply a matter of using your ever smaller hobby budget more wisely.


Using high nitro fuels in any sport model, used for recreation, is the wrong way to go. It simply isn't cost effective.


If you are racing and need to squeeze every last RPM from a given engine, it is a totally different story...

Added reliability?
40% nitro fuel is much more likely to cause your engine to fail catastrophically... Where would that fit into the equation?

quote:

ORIGINAL: RC-Bearings

Then we should all be flying hand launched gliders because we would get a lot more of them for the money.

quote:



...The point here is that the OS.70FS will perform better with higher nitro. It is up to you to determine whether it is the right thing for you to do.

quote:

ORIGINAL: DarZeelon

quote:

ORIGINAL: RC-Bearings

Then we should all be flying hand launched gliders because we would get a lot more of them for the money.

I don't agree, Paul.

It would more correctly be stated like this:

"We would find the route that would give us the most enjoyment from the hobby, within the time we can spend on the hobby and within the budget constraints we imposed upon it."

For me at least, 'flying hand launched gliders' cannot even appear within the same paragraph as the word 'enjoyment'.

quote:



...The point here is that the OS.70FS will perform better with higher nitro. It is up to you to determine whether it is the right thing for you to do.

I can agree with that, but would you tell all sport fliers (which is most of us, I believe) that they should always use 40% nitro, wear their engines out twice as fast and use up all their R/C budget within a quarter of the time, just because their engine will run 10% better on that fuel, than on 5% nitro?

I sure wouldn't.



The original question posted was probably not cost related, but dealt with the possibility of using 30% nitro fuel in this engine.
I would say no, because whether it happens from mis-adjustment, or from plain, accelerated wear, this engine will not live nearly as long as it would with the fuel specified by the manufacturer. It would clearly void the warranty as well.

quote:

ORIGINAL: FlyerBry
Another interesting test I could try would be to run FAI fuel in my Saito to see how it performs compared to 15% and 30%. Not so sure I want to try the FAI fuel though due to the high castor content.