Fuel choice for OS .65LA. . . (Full Version)

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Juice Man -> Fuel choice for OS .65LA. . . (6/10/2003 2:40:26 AM)

I'm going to run an OS .65LA in my trainer and would like to get you guy's opinions on which fuel I should use after running in the engine. "High performance" power isn't as important to me as reliability and longevity, so a very high quality fuel, that'll run easy in the engine and let it last long seems to be the way to go.

Planning on using a two blade 12x6 Master Airscrew (nylon/glass).

FAQ's and searches dont have the answers I'm looking for, so any help from you guys would be appreciated. :)




downunder-RCU -> Fuel choice for OS .65LA. . . (6/10/2003 7:14:30 AM)

The critical area on the LA's is the bushed crankshaft and this is what determines the type and amount of oil to use. Bushed crankshafts have been around for a very long time and back in the days when lots of castor was used these bushes just never wore out. Not so today where everyone uses normal RC fuels with very little oil and usually all synthetic.

From what I've read about American fuels the only one that's suitable is the Powermaster GMA 5/22 or 10/22 blend depending on how much nitro you want to use. This is the fuel I'd use to run it in with as well. Here's a link to their page.
http://www.powermasterfuels.com/control.htm
You could always use something like Cruel Power but you'd have to add a lot of castor to it to make it safe.

Another way to extend the life is to hand start the engine. Electric starters and bushed crankshafts can be a lethal combination (OK, so it can be a lethal combination with ball raced engines too :) ).




Juice Man -> Fuel choice for OS .65LA. . . (6/11/2003 4:25:56 AM)

Thanks for the input Downunder. . .

Power Master seems to be a well known, quality fuel. What do you think about their 10, and 15% "Premium Sport Blend"?

Search's for "Cruel Power" fuel didn't come up with anything, but I have read about Cool Power. I guess when used in Saitos it gives them increased RPM, and suposedly from what I've read from other people has good oil content. 50/50 blend of synthetic and castor, which Powermaster recommends to get the best of both worlds.

15% seems to be what I'm gonna use (if I can fit a 14 or 16oz tank in the plane), however Im not sure about which brand or blend. Will Cool Power 15% run well in an OS .65?

Anyone else have suggestions or opinions? The more the merrier :).

EDIT: I said Cool Power fuel uses a blend of Synthetic and castor lubricant. . .I meant Omega fuel, which is made by the same company as Cool Power, and does use synthetic/castor.




downunder-RCU -> Fuel choice for OS .65LA. . . (6/11/2003 6:45:08 AM)

You'd probably be OK with the Powermaster Premium Sport fuel but it's a bit low in oil for my liking, especially for that bushed crankshaft. As for Cruel Power...oops, sorry, Cool Power :) ...I believe they're one of the manufacturers who mix by weight so the actual oil content might be a bit lower than you're led to believe. Also, on their site you'll see they offer an FAI fuel which not only doesn't use enough oil but it's even the wrong type of oil. If they can't get that right then I wouldn't trust them with anything else either.

As for nitro content, I can't help there because I've never found any need for it. I'd suggest starting with the lowest possible though.




Jim C. -> Fuel choice for OS .65LA. . . (6/11/2003 7:35:34 AM)

i use coolpower 5% castor/synth mix.. total18% oil.. runs great.. nice vapor trail... and doesnt overheat.. have about 4 hrs on it so far and is running stronger every time!! any fuel like that will work ok




Juice Man -> Fuel choice for OS .65LA. . . (6/11/2003 9:49:08 AM)

In what engine Graupner? 65LA? Just curious cuz I wanna get an idea of fuel economy. . .

Downunder, are you saying I should break the engine in with say, 5% - 17% (30% Castor 70% High Viscosity Lube) Omega, then move up to 10 or 15% afterwards if I want?? Sounds logical to me. I may only go with 10% after its run in for better flight times. Probably wont need 15% on a PT-60 trainer anyway. . .




Jim C. -> Fuel choice for OS .65LA. . . (6/11/2003 10:46:59 AM)

yes.. that is the fuel i run in the 65la.. 12oz tank.. i can stay up for so far the longest was 26 mins.. that was being above 1/2 throttle for a good portion of the time. probably would have been longer but i quit timing my flights.. i just land when it runs outta juice!!!! deadsticks make you a better pilot!!!!! lol




Juice Man -> Fuel choice for OS .65LA. . . (6/11/2003 4:00:59 PM)

Haha

A 14oz would be good then :). I'd like to be able to fly for a day without having to refuel every 15 minutes. . .




Jim C. -> Fuel choice for OS .65LA. . . (6/11/2003 4:23:45 PM)

[QUOTE]A 14oz would be good then [/QUOTE] i would love to have a full gallon on board.. but i dont think the cg would ever be correct lol..not to mention the weight factor.. but a 14 oz tank would be nice.. you have to consider the weight and cg issue.. just a thought!




Bax -> Fuel choice for OS .65LA. . . (6/11/2003 7:35:23 PM)

Actually, for years we've used Omega and Wildcat Premium fuels very successfully in all of our engines, bushed and bearing alike. Both fuels are a synthetic/castor blend. We normally run the 10% nitro blend in everthing that comes through the house, except some of the 'exotic' engines, which require special fuels.

Either fuel will run in your O.S. Max LA-series engine very well.

We use those fuels because our company is a major distributor for them, and they're very good fuels. There are a lot of other fuels on the market that are as good.




tiggerinmk -> DO NOT USE COOLPOWER!! (6/11/2003 8:05:42 PM)

There, I think that was loud enough :D

My LHS sold me a gallon of 15% (green) Coolpower with my 1st engine (an OS 65LA) and it ran terrible. Not what you want in a new engine...

I switched to SIG castor fuel 10% and the engine ran a lot better. Now I run only semi synth, the castor helps with the lubrication.

I recently got a gallon of 5% Omega for my Irvine, and used it on my 65LA. Result? one dead plane.... When I dig the dirt out of the engine I'll run some tests on different fuels.....

Moral of the story? Stick with either castor or semi synth fuels, 10%-15% works well, either SIG or Byron... AVOID coolpower, the jury's still out on the Omega for the OS....

BTW both SIG and Byron use 20% oil..... turns out Omega is only 17% and only 30% of that is castor...




Jim C. -> Fuel choice for OS .65LA. . . (6/12/2003 2:42:29 AM)

why did it run bad?? mine loves the cool power... it was all that i could get at the time.. it will run strong with any fuel now.. if you broke it in with cool power.. i will admit it was sketchy at best .. but after about 5 tanks it started to accept it!!! lol..




tiggerinmk -> Fuel choice for OS .65LA. . . (6/12/2003 6:18:36 AM)

The 65LA was my first engine since returning to the hobby. I was sold the coolpower as a suitable fuel for it. The first run of the engine was at the flying field with the engine already installed in the plane.
The engine did not like the fuel, it vibrated badly causing the fuel to foam and air to get into the fuel line which made the engine run worse etc etc...

Changing to a castor based fuel helped, then later I replaced the tank and wrapped it in foam. The problem was then eliminated. Even then the engine was still tight and difficult to start.

It took me over a year to get that engine running right then two trees killed the plane. The 65LA seemed to like the 10%-15% semi synthetic fuels I used, but the engine with Omega 5% killed another plane.




downunder-RCU -> Fuel choice for OS .65LA. . . (6/12/2003 8:08:52 AM)

While I'll agree that the LA will run quite well on just about any fuel, Juice Man also wanted to know what will make it last a long time. These are two entirely different things.

The type and quantity of oil has to be based on any engine's most demanding area. This varies from engine to engine and sometimes it's only found by combined experience over many years. For instance, with the early LA's it was found that none peeled a liner if at least 22% oil was used (info from George Aldrich). The old OS 35S will wear out the big end rod bearing unless run on 25% all castor. A Fox 35 demands 29% all castor and will be destroyed in less than a tank of normal RC fuel (Duke Fox did it). A bushed crankshaft is a high demand area and extra oil does not reduce the power.




Jim C. -> Fuel choice for OS .65LA. . . (6/12/2003 11:19:25 AM)

[QUOTE]then later I replaced the tank and wrapped it in foam. The problem was then eliminated.[/QUOTE] soo... it wasnt just the fuel???? ;) ;) :confused:


DOWNUNDER: interesting tidbits of info... thanks!!




Dr Nitro -> Fuel choice for OS .65LA. . . (6/12/2003 5:07:46 PM)

Juice Man,

The 65 LA , like most engines will run on about anything you put into it.
However, if you want it to last like any of the LA series bushed engines, you need to run a fuel with castor in it, preferably 20% to 50% of the oil in the blend should be castor. I know that Hobby Services recommends 18% oil in the engines, but the LA engines really should have a 20% recommendation, with a castor blend or all castor.
I've had a few LA engines, a 40 and a pair of 65's. These mostly get the trainer use for the kids but they have seen lots of hours and lots of gallons.
I used to be a user of Omega like Hobby Services recommended and even an occasional gallon of Wildcat. Both fuels ran quite well in the LA engines (as expected), but the 40 and the first 65 got a real sloppy crankshaft to bushing fit in only one season of heavy use. The service is commendable since HS fixed them for us, but that's not the point; I was using the wrong fuel.
I used to fly a lot of control line years ago and should have known better about using a low oil fuel (under 20%) in a bushed engine.
After I got the engines back and starting about a year ago, I began running a 10% nitro/ 23% oil (cas/ syn blend) made by Cooper's in these engines. I will comment that the LA engines sound smoother and a lot less rattely with this control line type blend. All of the other fuel I run in my other engines is now a 20% total oil content.
If you want them to last, run a higher oil fuel than Omega, and never run an all synthetic fuel in a bushed engine.




Jim C. -> Fuel choice for OS .65LA. . . (6/12/2003 5:36:01 PM)

interesting info.. thanks doc!!




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