10% oil

10% oil (Full Version)

All Forums >> [Glow Engines, Gas Engines, Fuel & Mfg Support Forums] >> RC Fuels

Message

futaba1024 -> 10% oil (5/6/2003 9:06:12 PM)
Hi Guys. Been usung a comercial fuel, Model Technics Dynaglo 5 that has a total oil content of 10% (8%syn 2%castor 5%nitro 85%methanol) with absolutely no ill efects on various 2and4 stroke motors, according to most people there is not enough oil content. how come I've not wrecked several of my engines? Cheers

tps -> 10% oil (5/7/2003 1:22:11 AM)
I agree! Car engines runs just fine on just 8 or 9% oil together with 25% nitro. 3,5cc car engines produces almost 3 bhp @ 30-40 000 rpm I think the 20% oil limit is an old leftover from the stoneage... ;-)

tdriver -> 10% oil (5/13/2003 4:43:24 AM)
[QUOTE]Originally posted by tps I agree! Car engines runs just fine on just 8 or 9% oil together with 25% nitro. 3,5cc car engines produces almost 3 bhp @ 30-40 000 rpm I think the 20% oil limit is an old leftover from the stoneage... ;-) [/QUOTE] ..............couldn't agree more..............new engines are running on methanol last time i checked,not on oil.

JWN -> 10% oil (5/13/2003 11:07:44 PM)
My guess is the answer is two fold. 1) There are no thrust loads on the bearings in a car, or radial loads. This would beg the question on why helicopter fuel usually has more oil instead of less compared to airplane fuel. 2) The oil used in the Model Technics Dynaglo fuel is very high quality and therefore 10% total content is all that is needed. Read the article on Power Masters site written by Don Nix about oil content. Also read the article Stu Richmond wrote a month or two ago, I believe it was in RCU, about oil content. Both agree that it's the quality of the oil, not the quantity, that provides the protection. John

tps -> 10% oil (5/16/2003 1:57:01 AM)
Thrust load, maybe not, but I'm certain that a car engine have a much more stressful life than a airplane engine - full throttle, brake, full throttle, brake etc. Remember, 3bhp @ 40 000 rpm with an 3.5cc engine - thats impressive. One thing that comes to my mind is fuel consumption. 3.5cc on-road engines consumes about 125cc fuel in 5 minutes. More fuel throu the engine, less oil is needed?! I run my car engine with 25% nitro 3% synthetic and 6% castor - total 9% oil. The engine runs just fine and has no loss of compression after running over 15 liters of fuel throu it :-) I remember reading an article in an old issue of a UK magazine called RC Car Racer or something similar They were successfully running 3.5cc car engines with only 2% oil. The only downside they had was that the engines were harder to tune. I wonder what type of synthetic oil they were using, perhaps turbine oil?

JWN -> 10% oil (5/16/2003 3:02:25 AM)
Even though you are running through the oil that fast, the total percentage, and quantity, is still very low. I agree that the cars have a much more stressful life. In addition to the on/off throttle usage, there is almost more heat and dust. My gut still tells me it's the lack of thrust loads which allow the low oil percentage, but then, I don't run cars :) John

downunder-RCU -> 10% oil (5/16/2003 8:24:58 AM)
I've often wondered how they get away with it too. It won't be because of the lack of thrust loads because that's carried by the ball races and they're the part of the engine needing the least amount of oil. No matter how fast they're revving, if they're tuned right then the total amount of oil passing through per rev will be the same (and if you work it out, the volume is amazingly small!). Maybe because of the revs and because they're only peaked for a very short time then the oil doesn't get much chance to burn off? Maybe backing off gives them a chance to load up with some excess oil to help carry it through the next high rev cycle? The most highly stressed engines I know of are the 2.5cc CL speed engines putting out 2.7HP (genuine, not manufacturer's inflated figures :) ) at 40K+ using zero nitro and 20% castor. This is a regulated fuel though so possibly they might develop even more power with less oil or one with less drag.

tps -> 10% oil (5/16/2003 10:12:12 AM)
Another interesting thing is that if I run my car engine with high % oil fuel, the engine will run just like crap. I still think that this has to do with fuel consumption. I dont think airplane engines, in general, consumes 125cc of fuel in just 5 minutes. More fuel throu the engine - more oil to lubricate the internals. Lets say that a car engine uses the double amount of fuel per revolution compared to an airplane engine, this should mean same amount of oil in both engines at a given time. (using 20% oil for the airplane engine and 10% for the car engine) ???

JWN -> 10% oil (5/16/2003 7:41:05 PM)
Ducted fan, pylon and CL racing engines all use amazing amounts of fuel as well. Heck, my OS BGX burns through 24 oz. in less than 10 minutes at full throttle which is far more than your car engine burns. Car engines don't have thrust loads, only radial loads. Airplane engines have both thrust and radial loads. John

Homebrewer -> 10% oil (5/16/2003 9:52:17 PM)
Just exactly what kind of ill effects are you expecting? I don't think your engine will last more than 2-3 years of summer weekend use as opposed to much much longer.

downunder-RCU -> 10% oil (5/17/2003 9:22:36 AM)
[QUOTE]Originally posted by tps Lets say that a car engine uses the double amount of fuel per revolution compared to an airplane engine,[/QUOTE] Then the car engine would have to be tuned slobbering rich. Doesn't matter if it's a car, aircraft or boat engine, if it's tuned correctly then they all run the same air/fuel ratio (so long as it's the same fuel mix). The car engine only has a higher fuel consumption because it's turning far higher revs.

tps -> 10% oil (5/17/2003 2:15:49 PM)
I have tried running a Novarossi 3.5cc car engine with 18% oil fuel, the engine ran very erratic. In other words, it's useless. 3 years of engine life... That must be very rare with a car engine. I get one season, if I'm lucky. Somehow dust seams to find it's way into the engine and scratches the piston and other moving parts... ooch!

tps -> 10% oil (5/17/2003 2:24:28 PM)
[QUOTE]Originally posted by downunder Then the car engine would have to be tuned slobbering rich. Doesn't matter if it's a car, aircraft or boat engine, if it's tuned correctly then they all run the same air/fuel ratio (so long as it's the same fuel mix). The car engine only has a higher fuel consumption because it's turning far higher revs. [/QUOTE] Good point !!! What about nitro, I guess nitro fuel allow a richer mixture compared to non-nitro fuel.

Waco Driver -> fuel/oil mixtures (5/18/2003 6:24:30 PM)
This discussion is not taking into account the fact that since cars are operated in the horizontal position, they have a relatively constant fuel head at all times. This means that fuel/air mixture ratios are little affected between a full and nearly empty fuel tank. In an aircraft flown aerobatically however, fuel heads may change thru a range of perhaps 12 or more inches from nose up to nose down. If mixture is set slightly too lean on the ground with the model held in the horizontal position, it will be severely lean in the vertical climbing position. This is where the 18-20% oil in the fuel mix saves the day. If a model aircraft were always flown in a relatively horizontal position, say doing just circuits, with takeoffs and landings, you could probably get away with using 8-9% oil in the fuel mix also.

downunder-RCU -> 10% oil (5/18/2003 8:47:29 PM)
[QUOTE]Originally posted by tps What about nitro, I guess nitro fuel allow a richer mixture compared to non-nitro fuel. [/QUOTE] When you use nitro or use a higher percent you have to open the needle valve more. Methanol has a air/fuel ratio of 6.5:1 but nitro starts at 2.5:1 and can go much richer. If you use 10% oil and 20%nitro then you have 70% methanol. But the ratio of methanol to nitro (the actual fuel) is 7:2 or 3.5:1. If you up the nitro to 30% then you cut back the amount of methanol to 60% so now your ratio of methanol to nitro is 2:1 which is closing on twice as much nitro in the fuel as you started with. But because of the difference in air/fuel ratio you have to open the needle valve quite a bit to get the correct mixture. You're now flowing far more fuel which also means you're flowing far more oil and this might go some way to explaining why a car engine gets away with so little percent oil in the mix. The only problem now is helicopter engines. They tend to use 30% nitro but around 24% oil. Not only that but they run them rich! Go figure :)

JWN -> Re: fuel/oil mixtures (5/19/2003 8:08:50 PM)
[QUOTE]Originally posted by Waco Driver This discussion is not taking into account the fact that since cars are operated in the horizontal position, they have a relatively constant fuel head at all times. This means that fuel/air mixture ratios are little affected between a full and nearly empty fuel tank. In an aircraft flown aerobatically however, fuel heads may change thru a range of perhaps 12 or more inches from nose up to nose down. If mixture is set slightly too lean on the ground with the model held in the horizontal position, it will be severely lean in the vertical climbing position. This is where the 18-20% oil in the fuel mix saves the day. If a model aircraft were always flown in a relatively horizontal position, say doing just circuits, with takeoffs and landings, you could probably get away with using 8-9% oil in the fuel mix also. [/QUOTE] I disagree. Ever seen how a car is worked through the corners? There are pretty severe side ways G-forces at work on the fuel system. Especially when working through S-turns. Also, what about off road buggies and trucks which are constantly being jumped and tumbled? John

Waco Driver -> fuel head changes (5/20/2003 11:15:52 PM)
I believe any fuel head changes encountered in a car would be very transient in nature as compared to a more sustained duration in an aircraft in a long vertical climb. The latter would have far more potential to cause engine damage in the case of an over lean fuel/air ratio with low oil content fuel.

futaba1024 -> 10% oil (5/21/2003 1:09:26 AM)
Hi Guys. Think my original post has gone slightly astray, was not asking "if" you can use 10% oil, but saying I have been using that content for the last 10 years or so with no ill efects in all my glow motors, so why do we need 20% oil. cheers futaba

JWN -> 10% oil (5/22/2003 1:21:24 AM)
[QUOTE]Originally posted by futaba1024 Hi Guys. Think my original post has gone slightly astray, was not asking "if" you can use 10% oil, but saying I have been using that content for the last 10 years or so with no ill efects in all my glow motors, so why do we need 20% oil. cheers futaba [/QUOTE] Because 20% oil is what the "experts" tell us we must run :D John

FLYYBOY666 -> engine life (5/23/2003 7:02:53 AM)
In my years of experience with cars and rc Tuning is everything I have destroyed high dollar engines tweaking oil type and content.Every application is different.My best results has always been running castor synth blends 16 to 18 percent oil. I have super tigre engines that are 30 years old with unbelievable amounts of time on them that run start and perform better than half the engines out there.Invest wisely and look to the long term yeah great I run 8%wang dand doodle oil made from banana sludge and 20%nitro, my engine was screamin for a few weeks what happened. have a great day guys

Homebrewer -> 10% oil (5/23/2003 7:58:08 AM)
Hey, why stop at 10%, why not 5% or 2.5% oil? Based on the logic presented, you'd have to open the needle mixture to richen fuel flow since it has less non-combustible oil in the mix etc..etc..etc..

FLYYBOY666 -> comedy (5/24/2003 12:12:50 AM)
Hey man thats right,I think we should do stand up comedy.point wekk taken.He was right his original post went left for sure.have a great day flyyboy

Spaceclam -> 10% oil (6/4/2003 4:46:00 AM)
when you run on low oil content, it will not necessarily wreck your engine, but it will never perform as well as if you had been running on more oil. the performance is reduced, and the engine will not last as long. for instance, the os engines last 30+ years if you TAKE CARE OF THEM. i always run 20% oil. why do you want to run 10%? 20% has no drop in performance compared to 10%, and as long as it is tuned correctly, it will give you MORE power. if you are going to run on 10% oil, i would reccomend that nitro blast stuff. it works really well. what it does is suck the oil in your fuel into the actual metal making it "wet" and allowing you to get the most out of that 10%.

JWN -> 10% oil (6/4/2003 4:58:07 AM)
How is more oil going to produce more power? The oil is not a combustable part of the fuel and as such it does not make power. Quite the opposite in fact. The more oil in the fuel, the less power the engine MAY produce due to the oil prohibiting the complete burning of the combustable components in the fuel. The total content of the oil is not what protects your engine. The QUALITY of the oil does that. If you run cheap oil, you may still destroy an engine even with 30% of the fuel content being oil. OTOH, if you run an extremely high grade of oil, you may be able to go as low as 2%, possibly less, total oil content. John

FLYYBOY666 -> oil 0% (6/4/2003 5:53:12 AM)
Not the sharpest tool in the shed :stupid: I :stupid: would say.the correct amount of quality oil equals less friction.less friction more rpm equals more power.less lube, more drag ,more drag, more wear.more wear, busted engine .no engine equals no fly ,no fly equals one pissed monkey.not a single part of it is rocket science.I have been mixing testing home brew since I was 12 years old without any problems.clarence lee recommends 20-23% Castor synth blend.have a great day.ill probably catch hell for this one

Page: [1] 2 next > >>

SITE MAP! : : FORUM RULES

© 2001 - 2007 24-7 RC, LLC, all rights reserved.

0.2028809