aspeed

I like that flying video, nice flying plane. I wish I could get the snow to melt like that at the end of the flight :-) My MEK is the clear nasty stuff, not the resin. I spilled some and it was pretty wicked. I used the 5 gallon buckets of resin. Not worth the trouble any more with chopper guns, cheaper and easier to get guys to do it.

AndyW

My Feedback: (1)

Yes, thanks for reminding me to alert anyone using MEK for any purpose, that one drop in the eye can cause instant blindness. When used in fuel, it's never a good idea to get fuel of ANY type in your eye but MEK may make it far worse. But Again, Amsoil makes a cetane booster and it can be shipped by regular mail,,, at least the last time I got me some.

About the snow, yeah we had a flash Global Warming Event that day. Kinda freaky but we're getting used to it. :^)

hsukaria

All this talk about diesel fuel is making gas look a lot more attractive. Even glow fuel is more appealing than having to mess with model diesel fuel ingredients.

aspeed

Gasoline and diesel stink up the car real bad. Diesel is maybe in a better container. I would take glow fuel over either one any day. The cost is not really that much. Less than it is to drive to the field, unless you fly monster stuff, which I never will.

fiery

My Feedback: (2)

In quite a few parts of the world methyl alcohol (aka methanol, methyl hydrate) is a proscribed substance. Hence the need for alternatives - such as petroleum fuel glow engines or good old model diesel. That said, obtaining di-ethyl ether can be a headache for those of us who love oil burners and consider the odour akin to exotic perfume.

aspeed

The ether is used for crystal meth or something like that, so it is severely restricted and expensive. The spray cans for starting diesel trucks seems to be the only way to get it. I guess if you run diesel and castor mix, and just spray the ether in the carb for priming, it would be cheaper and not smell so bad, or at least have a longer shelf life. My wife gags when she gets a wiff of ether, it reminds her of a bad hospital visit as a kid, many moons ago. Diesel trucks used to make me sick when driving on the highway. I got an old Mercedes diesel a few years ago, and that seems to have helped with the sick feeling. I have since sold it, but it was kind of nice to drive, but the slowest thing I have ever seen. Parts were crazy expensive. One little fan motor which should be $50, was $500, and they would not stock the brush kit. I guess diesel would be more in my taste, as it is lighter and simpler than gas. I did have trouble starting my old Frog .15 as a kid. I never did get it to run. My flying buddy got it going for me and it was good, Just not for me. I have an electric starter now, maybe it is time to try again in the spring.

hsukaria

The NV gas engine is same weight as the glow and diesel. That was the big deal about it.

AndyW

My Feedback: (1)

All this talk aboot gas, :*) has got me curious.

Post cataract surgery, I'm supposed to do nothing for two weeks more physically demanding than doing the dishes . SO, I'm going to review this thread and take some notes. I can make my own high compression head and asbestos gasket and I have lots of copper head shims. I have at least a half dozen different carbs that are a drop in replacement. Top of the list is a heavy duty conrod. Testing may be sooner than the spring, we're getting bouts of weather well above freezing. Weird. In January, 40 below is the norm, at least for a few weeks.

The big question on all of this is why bother? We have a good engine that runs well on glow and glow is well established and there's not much left to learn about it.

The why is to compare performance, establish the pros and cons, and maybe learn something new. Neat.

Thanks for the inspiration guys, these days I need a little prodding to get some mojo back. :+)

hsukaria

Do you plan on doing this investigation on a 40 size or a 15 size engine? It would be crazy interesting on a 15.

The 40 gas head button is nothing more than a flat surface with a center hole machined for a turbo-style glowplug. No rocket science there. The other component is the high speed needle with a more gradual profile.

AndyW

My Feedback: (1)

Well, I DO have that Norvel .15 with the variable compression head and I did plan to run gas on it using Enya's special oil. Their big gasser doesn't use bearings on the rod. The reason why we need to use gross amounts of oil in our fuel is because our rods are bushed. Otherwise we could get away with the tiny percentages of oil that the weedwhacker engines use. They have roller bearings at both ends of the rod. Enya's big gasser has bushed ends and it appears that their oil is what makes it work for them. I ran the Picco .06 on gas but it was cranky to run and tinkering with the carb was problematic.

And so, as this thread is abut the GX .40 and apples to apples, let's try and resolve why some have problems and others not. And, apples to apples comparison, same engine with differing fuels is the goal here.

Thanks for the tip on the gas head but why a turbo plug? My experience is that turbos give no benefit to anything above a .15. I suppose Norvel tried a stock plug and simply found that a turbo was better for gas operation. I'll make buttons for both.

Does anyone have a spare gas needle to donate to the cause?

aspeed

So there is no bowl in the combustion chamber? How much is the head space nominally? Maybe I can try something from an LA .25 head that I made that gave very little gain. Too bad it is winter,, the garage is too cold for much machining, and outside is, well, outside. The LA may be simpler to adjust with no low speed needle.

hsukaria

OOPS!!! I went back and looked at a gas head button. It does have a very tiny conical recess in an otherwise flat head. I suspect that the use of a turbo plug is mostly to prevent compression leaks?

Anyway, the NV Engines website has spare head buttons and high speed needles. I don't know if the low speed needle is any different than the glow version, come to think of it.

Charley

My Feedback: (2)

Andy,

Did you ever come up with your list of replacement con rods for the AX/GX .40? I'd sure like to find a source for a stronger rod.

CR

hsukaria

+1

aspeed

Some guys were going back to the glow needles on the thread I was reading. I was wondering about the combustion chamber shape for a different motor that I would have to make up. It looks pretty basic, maybe a little smaller than normal. Hard to tell with no relief for the sleeve like a normal setup. I do like the Norvel way better, less chance or leaking from lift.

AndyW

My Feedback: (1)

Yes, certainly. I think it was from a popular clone, GMS? It was decently priced and well made with bushings both ends. Will do that today,, the eye is coming around nicely.

Charley

My Feedback: (2)

Good news about the eye. I had no probs with my cataract surgery.

I had the GX .40 in a GP Escapade. When I sent the GX to Russia for checkout, I replaced the engine in the Escapade with (drumroll please) a GMS .47! Can't get most parts for the GMS or the Tower engines now though. I have a spare Tower .46 mothballed however.

CR

hsukaria

I had the GX 40 on an Escapade also. It flew great until the GX bought the farm. Did you ever yours back from Russia?

AndyW

My Feedback: (1)

Sorry, spent an hour in the shop looking. I may have saved it to file. That's a bigger rat's nest than the shop dang it. Not to worry, I really need it myself.WILL find it.

Charley

My Feedback: (2)

I got it back last June, haven't run it though. Other projects took over my attention. Dmitry told me the Russ techs said there was nothing wrong with it but they replaced the HS needle "JIC" ! Yeah, right! I think those guys were lying like rugs and I told Dmitry just that. They had gone into their usual litany about how it was all my fault due to mistuning, etc, etc. Right; I and everyone else (except hllywdb) on this thread don't know how to tune a 2-stroke RC engine. IMO, those lying so-and-so's just won't admit to any faults in the engine.

You can see just how my enthusiasm has waned. Maybe the revival of this thread will remotivate me. I can mix up some more fuel and run it any time. I'll get back to you on it.

CR

hsukaria

I asked them why the crankpin broke and they told me to add a headshim. The theory was that I was running it too rich (see explanation above about ceramic liners and hydrolock). But the problem is you have to start the break-in process running it a little rich. But how little or how much rich is where I get lost. So I plan on breaking in the engines as glow because I am familiar with that and is easier than the gas. After that I will try gas again.

Charley

My Feedback: (2)

I still have the rod I bent. I could straighten it & make some measurements. Anyone still have some internal bits laying around?

By all means keep looking, Andy.

CR

hsukaria

You mean it went to Russia and back and they replaced the needle valve but not the bent conrod?

Charley

My Feedback: (2)

No, it went to Russia with the replacement conrod in it. I still have the bent one.

CR

hsukaria

The concern here is that if you still have the hydrolock issue and replace the conrod with a stronger one, you will break off the crankpin instead like what happened to me and the pope.