Gasser conversion?

[Atomic Skull]

What ever happened with this?

[richmurphy83]

+1 I'm waiting for someone to try the new os gasser in the Pantera. If it works out well I might have to bite the bullet and get a second Pantera.

Sent from my SCH-I605 using Tapatalk 4

[jbeech]

Other projects interfered. Specifically, the ProModeler ESC, motors, servos, and gyro Delayed but not forgotten, I fully expect to get back to this project.

[Atomic Skull]

Originally Posted by richmurphy83

+1 I'm waiting for someone to try the new os gasser in the Pantera. If it works out well I might have to bite the bullet and get a second Pantera.

Sent from my SCH-I605 using Tapatalk 4

I read a lot of bad things about that motor failing.

[jbeech]

The reasons are hard to discern. I have not written this engine off. Let's see how it plays out once I get back to it. At present my agenda is more oriented toward electric models because of user interest (follow the money is always good advice). Anyway, just be patient a little while longer, please, because I will get back to it. I promise you, I am not lazing about.

[richmurphy83]

Originally Posted by Atomic Skull

I read a lot of bad things about that motor failing.

I've heard bad things also.
But have also heard they have a revised piston assembly that seems to have resolved some of the issues.

Sent from my SCH-I605 using Tapatalk

[jbeech]

There's a new piston for the OS GT15HZ engine. I have a new in the box engine, which I am returning to them for the update before I proceed.

[brw0513]

There has been a suggestion elsewhere on HF that the GT15HZ will be released in a 50 size form factor. This should make it a drop in fit for many airframes.

I don't know for sure, but I suspect the many reported engine failures are because the engine just got too hot in the given application. Not enough cooling airflow and the engine temp might just run away. The big Walbro carb might just block enough airflow in a typical fan/shroud arrangement to make all this a reality.

The 50 size form factor variant might use a nitro style carb that is much smaller in size and reduce this tendency.

I also believe the GT15HZ could be a good choice with a 4-blade head swinging 550mm blades. 90 size cooling might still be a must.

Food for thought?

[bjnginge]

I can't wait for the day a reliable little gasser is an option.
I love engines, love electric on small stuff but fuel is good.
I was tempted to buy the 15mz, but the blowups are not a good sign.hopefully bugs will be sorted out.Will have to wait a while as big electric although powerfull bores me to tears

[flyingquisinart]

I had been following a Gaui gasser thread a bit and that motor seems as unreliable as the Os unfortunately. Seems people are running it really rich and following the break in procedure and motors are still failing. That motor is a little small for the Pantera anyway.

Matt

[jbeech]

Folks, I'm sorry I've been too busy to get back to this project. I am reasonably sure I can make this project work, but between introducing our new line of servos, expanding our facilities, plus some nagging little health issues, I've let this slip between the cracks. I hope to turn my attention back to it and offer results in time for the 2015 flying season.

[bjnginge]

That's excellent news JB, hopefully my 4 blade head will be all installed and ready for a gasser by then.
Keep at it and keep us informed, would be an excellent upgrade
Brad

[brw0513]

I think the mixture control feature of the Aerospire MultiGov could be a good way to keep temperatures in check. As the engine temp rises richen up the fuel mix to help keep the temperature in check. Lean the mix as the temp comes down.

Just my theory.

[jbeech]

Been there, done that. The only problem with this is it doesn't really work on gassers. It's because as the mixture richens, the engine begins to stumble and loose power. If you've ever adjusted a needle valve on a lawn mower engine while it's running (you know, where you turn it one way until it begins to run rough, then turn it the other way until it begins to run rough again, then set it in the middle), it's the exact same with gasoline burning model engine.

What has more of an effect on cooling is increasing the oil content. However, this has its limits as well. For example, the engine may specify a 32:1 mixture, e.g. 1 part oil for 32 parts gasoline - or 4 oz of oil - in a gallon, which is 128 oz. Also, you can go to 16:1, or 8 oz of oil/gallon so the engine runs a little cooler but then it may oil-foul the spark plug (as well as begin to build up carbon, which flakes off and pre-ignite, as particles glow red with heat and ignite the incoming mixture before it's supposed to).

A happier medium with respect to oil content may be 5-6 oz of oil/gallon, but then the engine isn't developing full power. Worse, this opens another can of worms entirely with respect to tuning. Believe me, it's tricky business cooling the gasoline fueled model engine. If it were trivial, the forums wouldn't be rife with reports of that OS baby gasser blowing up.

Meanwhile, we've messed with the concept of using the Aerospire to control an electric cooling fan. But as it turns out, this may be getting too tricky by half because as it turns out, it may just be better for the fan to run all the time. But like I've said, I've not given up, and this conversion is on my list of things to mess with . . . I promise!

Finally, and not to blow my own horn, but I've produced a DVD about model engines. It runs over 3 hours and includes info about baby gassers, as well as all varieties of glow engines (2-strokes, 4-strokes, Wankel), plus ignitions, spark plugs, adjusting valves, selecting glow plugs, fuel composition, etc. It's available on our website here:

aboutENGINES: http://www.audacitymodels.com/Produc...3/Default.aspx

This program was specifically conceived to help bring folks up to speed on a host of issues when dealing with model engines. It's one of the works of which I am most proud. Last thing, there are dozens of television programs created by modelSPORT, of which I am host and which, you may find interesting. Just poke around on the website and look.

[Atomic Skull]

Originally Posted by jbeech

A happier medium with respect to oil content may be 5-6 oz of oil/gallon, but then the engine isn't developing full power. Worse, this opens another can of worms entirely with respect to tuning. Believe me, it's tricky business cooling the gasoline fueled model engine. If it were trivial, the forums wouldn't be rife with reports of that OS baby gasser blowing up.

There's a reason why the Zenoah RC is the most popular gasser helicopter engine despite basically being a weedwhacker engine - it just works.

[jbeech]

The Zenoah just works. Yes, but . . . during a crash, because it's so massive, it may rip apart frames and wad the heli into a ball of mangled components wiping out expensive bits in the process.

Me? I've lost count of the $500 crashes I've seen. Thus, the huge advantage derived from making a lighter engine work comes about because crashes become 'normal' affairs once again. Case in point, the normal Pantera 50 crash is about $38, a figure which hasn't varied much in many years. I don't know about some guys but for me, that represents a heck of a lot of fuel, which proponents of gasoline engines are generally seeking to save money on.

Ultimately, I'm reminded of that old song about 'all that glitters isn't gold', and view prospects of saving money by using a gasoline engine (because it uses $5/gallon fuel) to be a similar thing.

[brw0513]

What does get me thinking is why the smaller capacity gasser engines, with the more typical nitro form factor, haven't really found a happy home in a model helicopter application. Not yet anyway.

The plank fraternity just seem to have their equivalent engines work. I guess that application has the benefit of "free" cooling airflow and the engine gets to operate over a range of speeds so the operating temp gets the chance to cycle.

I'm hoping a solution for heli use is out there. It would be great to get a truly plug and play gasser option for the P6.

I visit this forum every month or so to check!

[richmurphy83]

I am also soo anxious for a gasser that is a good fit for the Pantera. I currently have all the components to go 12s electric just haven't found the ambition to do so but now im thinking otherwise. I have been flying only electric helis lately and really miss the noise and longer run times of liquid fuels.

Sent from my SCH-I605 using Tapatalk

[brw0513]

A gasser P6 is probably the ideal model for me. I'll never be much other than an average flier but realistically happy to settle at that point.

Investing much more is probably dumb. And the gasser engine would satisfy my need for some "working class exotica".

I have been wondering if the pressurised CO2 cannisters that the lycra clad bicycle brigade use to fill their inner tubes with couldn't be adapted to cooling duties for a gasser engine. I've got the needle valve out of an old and basic OS carby. With an adaptor it might just make a reasonably good expansion valve. I'm going to have to try it just to see how good an idea it is. Maybe an Aerospire Mutligov could control the needle position to give a reasonably lengthy blast of cold gas based on cylinder head temp?

[richmurphy83]

Those tiny co2 cartridges dont hold nearly enough to be a viable cooling option. Now a paintball co2 tank............. lol but way too heavy.

Sent from my SCH-I605 using Tapatalk