AMB

Being gasoline base do you really need castor oil, seems a regular motor oil would work maybe mixed with some synthetic martin

hllywdb

AJsToyz,
While I certainly can't speak for NV, since of all the motors I am testing, they chose to let me post a video of this one, I would think they are getting closer to that point. But I would not speculate as to how close.

AMB,
I learned years ago (the hard way) to stick to manufacturer's recomendation on these things as they are far more versed in the metallurgical makeup of the components in the engine, heat expansion rates, tolerances, and loads imposed on varrious components. Some of you may recall in the Vintage forum I did a project a while back where I, along with my daughter, restored my grandfather's (her great-grandfather) 1970 Lou Andrews H-Ray. It was a fun project and we covered it in fabric, but used a more current radio. That plane also sports a 1970 OS 30. Back then OS recomended a 25% oil content. Yes, it requires mixing small batches of added castor and yes, it is more messy to clean up. However, it is a 42 year old motor that still hand starts. So, while some may choose to experiment, for the motors I fly every week, I'll just stick to what they tell me I've also found that even in larger 2 cycle motors, outboards, dirt bikes, etc that oil content and makeup matters much more than you think sometimes.

Sport_Pilot

Feat? Why would it. We use unpumped carbs on glow engines all the time, some convert them to gas with the same carb. We used gas back when with just a venturi and spraybar. The carb would be smaller because you cannot burn as much gas? Similar to Diesel with their smaller carbs. I think the large gas engines need the pumper carbs because the larger engines and tanks place the tank centerline further back from the engine, so a smaller engine doesn't require the pumper carb.

aspeed

In Brazil where they run alcohol/methanol or whatever, they have very small carbs compared to the gas carbs.  The mixture is much leaner on gasoline by double or so.  They do it more for economy  than performance.  I would think a gas carb should be a bit larger to get the proper mixture till the point where there is no draw.

Sport_Pilot

Gas carbs are smaller because they have less fuel. With alcohol and methanol the fuel displaces much of the air so the carb is bigger, plus the extra power means more revs so then more air to boot.

When they convert glow to Diesel they set up the carb to open only half way or less. If you allow to open fully it will lean out. If you adjust the needle for the mixture you will have very little extra perfomance and with the same prop less RPM. You have to switch the prop to a larger size or higher pitch to account for the lower speed, and restrict the carb opening. I would think gas would be similar though less pronounced.

hllywdb

My experience has been the same as aspeed's. Gasoline reqires a different fuel/air ratio and needs a larger carb to do this efficiently. With a simple C/L venturi, you have more lattitude, at least on glow engines, because you are adjusting the mixture for a given RPM (WOT). But I have found the larger you go, the more you run into the need for crank pressure or a bladder tank. An R/C carb is much more complicated and has to deal with transitions. To this end the smaller the carb, the easier it draws as it has increased vaccum.

hllywdb

Hi Sport_Pilot,
I think you are correct as to why most attempts to simply convert an RC glow engine to gas give less than satisfactory results. In this case, their gas version actually spins the same prop FASTER than the glow version, not at 2/3 the speed, which is the norm. This is probably what required a completely new carb that was designed specifically for gasoline. The fact that it draws well despite the fact of being larger and drawing thicker fuel, indicates to me at least, a good bit of engineering on their part.

AMB

Back to the castor oil thing, re-thinking this it may very be prefered over motor oil, true gas engines such as weed eaters, chain saws, are RINGED engines martin

Sport_Pilot

No. The carb will take in the same air minus the fuel. So since the fuel is less the carb takes on more air. Gas has less power, so the RPM goes down, thus less air and a smaller carb.

Raptor39

My Feedback: (10)

Hello Guys,

I can attest that what Bill is reporting on this engine is true. I met him for the first time last weekend at Airmaster's funfly and picnic.

He was by me in the pits and did notice he was flying a Norvel engine. It attracted my interest as I have not seen many Norvel that large. I really wasn't able to tell it wasn't glow when it was flying and found out it was running on gas after asking him about the engine. There is not much that looks different than a glow engine. It does run good, I was impressed.

Being that is is made in Russia, I thought it would run on Vodka too though.

Good work Bill. I look forward to seeing you again.

Rusty (the guy who was training the 13 year old with a PT 40)

NM2K

My Feedback: (14)

The next thing we know, dogs and cats will be living together...


Ed Cregger

hllywdb

Thanks Rusty, it ws good meeting you.
"Running on Vodka" Hmmmm, you know, in theory......... But it may be tough to find it for $4 a gallon. Then you would have the guys than ran nothing but Sminoff, the guys who swear by Absolut.... Then the sponsorships at the Nats would start to look a lot more like NASCAR or NHRA

AJsToyz

The engines would be starving and the pilots dreaming of flying? Lol

Twin_Flyer

My Feedback: (4)

Its been about a month, any updates on the engine!?

Bill S.

hllywdb

Well, I have started building a 46 size Ultimate Bipe from scratch, and I also have a sort of Frankenstien Pizzaz (Pizzaz wing and tail, with a modified super sportster style fuselage) that is about 3/4 done so I was thinking about trying it in both of them.

So I thought I'd try some larger props as both planes will need them. I'm not fond of just bench testing with props as the motors run completely different in the air. So I ran it a few flights with an 11X6 APC, (a bit large for a 40) but had some interesting results. It seems the motor acts just like a nitro motor with the standard 10X6 props. But when I loaded it up with the 11X6, instead of lagging, it seemed to run even smoother. This may be due to the way gas burns vs nitro, but it seems it's realy the torque that powers this motor more than HP. The plane flies a bit slower with a 6" pitch as you would expect, but has more thrust than even the 10X6 spinning faster. It seems you don't get as big a drop off with the larger props that one would expect. So I may see how it does with a 12X5 or 6 as well. But I realy like the way it runs swinging the bigger lumber.

hsukaria

I like big props.

Twin_Flyer

My Feedback: (4)

Did anyone notice Evolution just came out with a 10cc gasser?

have to wait till after the holidays to get one, but I plan on it!

Bill S.

[email protected]

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are you useing regular fuel do you use oil in it regular plug thanks

AJsToyz

I have been following the other thread.i still do like this engine because you do not need the ignition, helps with smaller birds.

hllywdb

Hi AJ,
Yes, it's tough to beat 13oz all up and swinging a 11X6, leaves all sorts of planes to put it in. I find the 46 size planes fly best if you can keep them light. I'm not a big fan of 4 strokes in that size as they just get a bit porky on the weight.

Oneaw,
It uses premium pump gas with oil. No it's not a standard plug.

I have had no flying time durring the holidays, time off but cold snap last weekend, now it's back in the 80's but blowing over 20mph. Go figure

AJsToyz

Here's another question, have you tried running it on racing fuel? There are a lot of people out here that like the benefits of gas, less slime, better economy, but don't like that gas smell. These people tend to use things like AVgas, Coleman fuel, or racing fuel. Just wonder if you have tried any of these in the abuse testing?

Andy

MJD

My Feedback: (1)

The volume of fuel per cycle is so small as to be insignificant - I just went through the exercise of figuring this out 3-4 weeks back because of the comments I kept seeing about how increasing oil percentage in glow fuel cuts power due to diluting the fuel mixture. For 20% nitro, 20% castor glow fuel at stoichiometry the ratio of air to fuel volume is 3495:1, while the mass ratio is only 5.1 : 1. Don't forget that fuel is ingested as an atomized liquid, not in gaseous form, and that the air:fuel ratios we talk about are mass ratios, not volume. Otherwise a .60 would pull an ounce of fuel about every 20 revolutions.

On suction fed engines the bore diameter is a function of the displacement and the rpm. The faster you spin an engine - displacement fixed - the higher the air flow rate, as it needs to ingest the same volume of mixture in less time. Since the maximum pressure differential between atmosphere and the crankcase is naturally fixed (you can't suck harder than zero pressure), the only way to flow more mixture is with more cross-sectional area - a bigger hole.

NM2K

My Feedback: (14)

Well put, MJD. I don't have a clue as to what you said, but I'm sure you are right. I love these kinds of discussions. Everyone has their own pet theory regarding this or that. Please explain to me how gasoline fuel provides more power than methanol. I need cheering up this morning and a good laugh just might do it.

I am not calling anyone a liar or even saying that they are wrong, in this regard. I simply do not understand how something so entrenched in our hobby for so many years as methanol producing more horsepower than gasoline in identically sized and developed engines can change over night without any explanation of how this miracle has been accomplished. Remember the BME modified gasoline/oil fueled Super Tigre .90 engines? They were claimed to make as much, or more, power than the glow version from which they were made. I had one, but never got a chance to run it before hearing that BME was in financial trouble (years ago), so I sold it before it was an orphan. Wish I had kept it now.

Happy New Year to everyone.


Ed, NM2K

downunder

To a close approximation, petrol has twice the heat energy of methanol (per pound/gram/ton,whatever) meaning petrol is twice as good a fuel as methanol. However, because of wildy different air/fuel ratios, you need roughly 3 times as much methanol to burn completely in the same amount (volume, mass) of air. That boils down to petrol only being able to produce about .7 the power that methanol can. There are a couple of other factors involved that can help methanol give an even wider power gap but that's nit picking.

[email protected]

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how much oil to the gallon and what kind of oil and plug