Truckracer

My Feedback: (19)

Hmmmm, I believe I suggested that 10 posts and 4 days ago! Not sure where you're going with the fuel pooling thing, etc. Other than a tiny bit of exhaust residue difference, there should be almost no difference between running say a 30:1 mix compared to a 50:1 mix ..... if the engine is tuned properly. Repeat ..... if the engine is tuned properly. If anything, you might notice a bit more power with the higher oil content mixture. I continue to run a 32:1 mix of Stihl Ultra HP and only notice a tiny bit of oil on the airplane and then only on planes with short exhaust stacks. With longer stacks, there is almost no residue on the plane. Remember, if you mix oil in the fuel, though some of it is usually burnt, the rest of it has to go somewhere. Some synthetics such as BelRay H1R for most purposes do not combust so most of it is expelled from the exhaust unburnt.

Skinny Bob

My Feedback: (12)

Truckracer, I mixed up a gallon of ethanol free gas ( don't know if ethanol makes any difference) with STIHL HP Ultra at 32:1 ratio and was impressed with the difference of how my engine preformed. I had to set the needle settings at DLE's start up setting to get a good idle and transition to WOT and back to idle, now tell me what you think of why I had to change to a lower throttle curve setting after changing to the STIHL oil. One more question, how should I store this engine over the off season, wet or dry carburetor?

Thanks
Bob

captinjohn

I store carbs wet...but only using Pure gas which leaves no sediment or varnish. http://pure-gas.org/ I have stored them with method for over a year, and they started right up !

Skinny Bob

My Feedback: (12)

captinjohn, thanks for you reply, there is a gas station in my area that offers that option at at $4.31 / gallon, I love gassers !!.

Thanks
Bob

thepamster

Glad you gotter goin' Bob.
Anytime you change oil brands, ratios, gas type, or props, a slight change in needle settings may be required.
This also applies to a change in seasons sometimes, though not always.
Happy Flyin'.

captinjohn

My guess it has to do with the viscosity of the mix. If one mix has a higher viscosity (thicker) than the other mix, the amount of fuel that passes through the tiny openings (jets) will differ somewhat. A thinner viscosity will pass more freely ...so you may need to set the mixture more lean in that case. Does that make sense?

Skinny Bob

My Feedback: (12)

Yes it does, I had changed from Lawnboy for break in to STIHL ultra synthetic, It did for sure make a difference.

Bob

thailazer

There are thousands of two stroke weed wackers used by the farmers over here, and no name brands of oil available. The engines appear to last forever if you mix your fuel consistently and don't run them too lean. I will do some checking and ask what ratios they are using but my guess is that it is close to 30-1.

av8tor1977

My Feedback: (6)

With different oils, and different ratios, two things happen that can change the mixture. One is as mentioned; the viscosity. The other is that the part of the oil that does not burn, takes place of gasoline and effectively leans the mixture, or vice versa.

AV8TOR

CARS II

My Feedback: (7)

If the recommended oil per gallon is 32:1 for the DLE engines during initial break in, what is the recomended oil per gallon after the engine is broken in?

ahicks

My Feedback: (2)

It has to do with the size of the engine. All the 20's need 32:1 during and after break in. When you get to the 26's on up you can go 40 or 50:1

If you have both, the 32:1 runs fine in the bigger engines as well.

Skinny Bob

My Feedback: (12)

The DLE 20 manual states 30:1 after break in. Don't believe the 5 gallon amount through it for break in. At 32:1 using the Lawn Boy ash less oil that DLE recommends you will notice a lot of oil coming out the exhaust, this is normal, the engine doesn't run on oil, the oil is only for lubrication. I ran a full gallon a 32:1 and then switched to STIHL synthetic and the engine is running great. With the synthetic oil at 30:1 there is very little oil out the exhaust and I am getting a good idle speed as low as 1770 rpm right where it should be. Also after you switch to synthetic you will have to readjust the needle settings. If you can find RED LINE synthetic oil in your area get some, it's the best. If not go for STIHL, like the man said, chain saws take a beating and that proves there oil is good.

Bob

CARS II

My Feedback: (7)

I am asking because I am currently running Red Line oil in a BME 61cc twin cylinder ( my first gas engine ) with an oil ratio of 50:1 ( I got it used in excellent condition ) and I got me a DLE 35re recently, the manual on the 35re calls for an oil ratio of 30:1 which is what I'm planing on using but can I go to 50:1 after the break in period? I will also be using Red Line oil for the break in and after the break in period for this engine.

CARS II

My Feedback: (7)

What is the porpuse of the different oil ratios, I can see that the bigger the engine the less oil per gallon, what kind of results will I get if I change the oil ratio on the BME, from 50:1 to 30:1.

I'm trying to only have one can of fuel for both engines.

I can see that with the Red Line oil I hardly get any residue on the belly.

Truckracer

My Feedback: (19)

As a rule, Chinese engines run longer and happier with more oil. I'd stick with 32:1 if it were my engine. Your BME 61 will also run just fine on the same mix if you only want to carry one gas can which is what I do. Tuned correctly, you will only see a tiny bit of difference in the amount of oil residue on the bottom or your plane.

Regarding oil burning in the combustion process ..... it depends on the oil. Most oils (conventional and synthetic) largely burn in the process and are considered part of the fuel. Only a small part of the total oil passing through the engine is expelled unburnt to show up on the bottom of the airplane. There are synthetics that largely pass through the engine unburnt .... such as BelRay H1R. You can do the research to find which oils burn and which ones do not. If there is excess oil on the bottom of the plane, in most cases I'd guess the needles are set too rich.

CARS II

My Feedback: (7)

I will be replacing the piston ring on the DLE 35 for a Bowman's one before it sees any fuel and will be using Red Line synthetic oil from the first start.

I learned to tune my nitro engines really good and with the gas engine I'm learning really fast how to run them right, not to lean, not to rich but preferably on the rich side.

Truckracer

My Feedback: (19)

While the Bowman ring is an excellent product, (I have them in 3 engines) you might want to hold off awhile before installing one in your new 35. The newer DLE rings are really quite good as supplied. Good enough I don't see a reason to replace them unless deemed necessary later on which I doubt will happen anytime soon. If I was going to re-ring one of my engines, it would certainly get the Bowman ring though!

Regarding High Speed needle settings on a gasser, I pretty much run up to peak RPM with the setting and back off just to know that I'm just rich of peak setting. For all practical purposes, they are running at peak and are only richened or leaned further if it seems necessary after flight testing. There is no real reason to run these engines overly rich but they have to be well cooled using baffles when necessary. Gas engines cool by airflow "through" not just over or past the cooling fins. For practical purposes, fuel flow is not a cooling aid as it is with glo engines.

CARS II

My Feedback: (7)

I see, I'm with you on the high speed needle settings, with the BME I have noticed recently that once it is warms up in flight to normal temps it likes to run a little lean so in order to land slow I have to drop the idle by three clicks of trim.

I'm also with you on the ring and also heard the semething regarding the rings on the new DLE engines.


Thank you all for the info.

speedracerntrixie

My Feedback: (29)

Carlos, that BME is going to retain heat a bit more then other brands of engine. Keith usually went a bit light with the construction of those engines. Running it in a big open cowl like your Gee Bee and the air is going to take the path of least resistance which is usually not through the fins. Most guys with round cowls will block off the top and bottom and leave windows right in front of the cylinders for air to get in. this is a help but should be backed up with baffles that extend halfway past the cylinders top and bottom. As far as oil ratios are concerned, the BME will run just fine on 32:1.

Too bad this thread didn't happen sooner. I was at the Sacramento Area Modeler's field all last weekend participating in the warbird race. I would have invited you to come by with the Gee Bee.

CARS II

My Feedback: (7)

Speed

If I had known you ware there at SAMS, that is the club where I have been doing all the testing and flying as a mamber, I wanted to fly the Gee Bee on that weekend but decided to stay away from the air races, the Gee Bee is flying really good now, instead I got to fly it in Half Moon Bay at my old club, put in three good flights and I'm getting used to how it flys now, having lots of fun with it.


I was home also to check out my new GP Citabria 30cc that I got last Thursday ( my next gas project ) I may have to swing by The Tom Cats field to meet with you one of these days.

Thank you for the tips and info on the engines.

CARS II

My Feedback: (7)

One more thing, I did noticed the cowl set up on other Gee Bees and they look like the way you discribe it, my airplane has a dummy radial engine on the cowl and I trimed it some more to allow more air to flow straight in into the cylindres, in a way it looks like the ones I have seen restricting the air flowing in, no baffles though.

speedracerntrixie

My Feedback: (29)

That's too bad Carlos, I was flying my Extra on Friday and Saturday evenings. Next year you should consider coming out and flying with us. Every Saturday nite we fly sport airplanes until dark then some guys break out with nite flyers. We BBQ and have a pot luck style dinner right at the field.

CARS II

My Feedback: (7)

I sure miss that, I was at the Castle fly in early this year, that was a blast, on Saturday we also had BBQ and night flying, that was a lot of fun.