RCHS1

My Feedback: (1)

http://www3.towerhobbies.com/cgi-bin...&I=LXEJRK&P=ML

OS seems to have 2 airplane versions of their pricey 15cc engine. I came across this one which say it is glow or gas and does not require a ignition module for gas -- Anyone heard of this Yet ??? Maybe this is a too good to be true scenario. Removing 3.5-4 ounces of ignition on a engine this size is a pretty big deal .
O.S. GGT15 Glow Gasoline


This is the Gasoline Powered GGT15 Engine w/E4040 Muffler from O.S. Engines.
**Additional Technical Info Will Be Added When It Becomes Available.**

[TABLE="width: 100%"]
[TR]
[TD]FEATURES[/TD]
[/TR]
[/TABLE]
Ideal for larger 2-stroke .61-.91 class models, and 4-stroke .91
class models
Glow plug ignition eliminates ignition module and reduces weight
61H carburetor with PD-08 pump system
Shell type roller bearings
Two year limited warranty through Hobby Services beginning at date
of purchase

[TABLE="width: 100%"]
[TR]
[TD]INCLUDES[/TD]
[/TR]
[/TABLE]
GGT15 Engine w/E4040 Muffler

[TABLE="width: 100%"]
[TR]
[TD]REQUIREMENTS[/TD]
[/TR]
[/TABLE]
Fuel: Gasoline and 2-cycle oil in a 50:1 mixture
Propeller depending on aircraft: Sport,13x8-11
Acro, 14x8-10
Scale, 15x6-8
Glow starter & field equipment

[TABLE="width: 100%"]
[TR]
[TD]SPECIFICATIONS[/TD]
[/TR]
[/TABLE]
Displacement: 0.912 cu in (14.95cc)
Bore: 1.091" (27.7mm)
Stroke: 0.976" (24.8mm)
Practical RPM Range: 2,000-11,000
Output: 2.35 ps/2.32 hp @ 15,000 RPM
Weight: Engine, 21.5oz (610g)
Muffler, 6.28oz (178g)
Distance between Mounting Hole Centers Same Side: 0.98" (25mm)
Distance between Mounting Hole Centers Opposite Side: 2.04" (52mm)
Width at Mounting Tabs: (61mm)
Width of Crankcase below Mounting Tabs: 1.7" (44mm)
Width from Crankcase Center to Exhaust Outlet: 4.4" (112.3mm)
Height/bottom of Mounting Tabs to Muffler Bottom: 1.5" (37.6mm)
Length/Crankcase Center to Drive Washer: 2.6" (66.8mm)
Length/Crankcase Center to end of Crankshaft: 4.03" (102.6mm)
Length from Pump to end of Crankshaft: 5.6" (142mm)
Crankshaft Size: UNF 5/16-24
Rearward Needle Valve Angle Relative to Engine: 30°

jxs 07/01/14

Steve Percifield

My Feedback: (14)

this is a glow plug ignited, gasoline fueled engine. it does not use a spark plug, thus no ignition module.

Gray Beard

My Feedback: (-1)

400 bucks is a bit of a sticker shock. One of the beauties of a gas engine it getting rid of all the support gear needed. Lack of weight is a good thing though but 400 bucks?? That would buy a lot of glow fuel.

CafeenMan

Sounds like OS is doing what Norvel did with their gas .40.

ira d

I like the idea but at $ 400.00 that is a little on the high side IMO. I will bet in a year or so DLE and some of the other engines will have this system.

CafeenMan

I would do the math to see what the difference in cost is. Figure the cost of a comparable glow engine. Then figure in $25/gallon for glow fuel and flight being about 16 ounces.

Then figure $4.00 a gallon for gas and 12 ounces for the same flight with the gas engine. I'm guessing on the tank sizes since I normally fly much smaller planes.

How much is a comparable glow engine? About $250 or so? 7 gallons of glow = $175.00 making the total cost $425.00. 5.25 gallons of gas = $21.00 making the total cost $421.00 for the gas engine (using 3/4 the fuel is how I came to the 5.25 gal gas vs. 7 gal glow).

So depending on how much you fly you break even in less than six gallons of gas assuming I approximated costs correctly. That doesn't count how long glow plugs last vs. spark plugs or other related stuff.

ira d

I can still get glow fuel for around $16.00 a gallon and sometimes less on sale as far as spark plugs they tend to last a lot longer than glow plugs. Right now
there are many gas engines on the market for a lot less that have a proven track record, I know OS tends to make good engines but this gas with glow ing
is something new that I want see perform for a while before I buy.

jester_s1

With it not having an ignition, it should sell for less, not more. Agreed, OS makes a good engine, but this is only about 10% cheaper than a DA 35 and about 25% more than a DLE 30. What are we actually getting for our money in this little gasser aside from it being the newest thing out? I can't imagine there being that much engineering that had to go into making a gasser run on a glow ignition. It's been done before by modders many times.

ideas

Has anyone given this engine a try ?

JohnBuckner

My Feedback: (1)

Yes I would very much like to hear from anyone who has acquired and started to operate this engine and please pay no attention to those who always belittle any OS engine on the cost basis. Direct cost comparison with 30 and 35 cc engines is pointless and irrational. This is not about those and that type of airplane, its about smaller airplanes and indeed the relative improvement in overall weight of the (extra switch, extra battery, ignition module, spark plug and heavy high tension wire) is very much a factor in the smaller model. That's the bottom line here, thirty cc or bigger airplanes can go hang! They are not what this is about.

I do have one example of the spark ignition GT 15 and there are at least four others flying locally and they are proving to be excellent and enjoyable engines to operate that the fellows love as well as myself. So am I interested in this glow/gasoline version? Oh you bet.

Patiently waiting for any ones report on this engine.

John

jester_s1

My only point with comparing them to the cost of the bigger engines was that in general, engines cost more as they get bigger. So given that these are so much smaller, they should be cheaper. Yet they are not. I'm truly interested in how these perform as well, and I'm also truly interested in what kind of engineering challenges had to be overcome to make them run right. Who knows? Maybe OS spent a million dollars solving some problems inherent with making them work and so has to recoup that in the retail price.

CafeenMan

I would guess the reason it costs more is that OS probably has a more costly operation to begin with. Then they have a reputation so the engine is going to be well made throughout and it will be backed and supported properly. And finally they get a premium for who they are.

I don't know enough about the engineering of engines to have an opinion but I think the biggest obstacle to overcome is the weight of an ignition. The electronic ignition took away a lot of that weight while the module gives a percentage of it back.

JohnBuckner

My Feedback: (1)

I have a number of even smaller displacement engines in the .40 and .50 displacement class two strokes that have cost over that four hundred number for many years now. However just because engines have the OS handle they are automatically ridiculed because of cost to the point I know some who hide the fact that they actually use and love some OS engines. That's a ridiculous situation.

Are all OS engines great? Aw hell no but I believe that the current OS line has the highest percentage of truly great engines in their lineup. I am talking of current line actually out there for sale engine models and not some vintage made in Italy or Katmandu stuff.

John

CafeenMan

Well, John, I just paid $450 (minus a couple discounts automatically applied by Tower) for a new Wankel. I think it ended up being $390.00 because that's the promo they had when it came off back-order.

I could get that same power at probably less weight for what, $130?? But it's just a cool engine. I already have a wankel and it's got a gazillion hours on it and still runs great.

Everything I read said the internal seals wear out quickly but I've never replaced mine and no problems at all with the engine.

People spend $50K on a model airplane. It would be interesting to find out what the cost per flight is for every model we've ever built. If you have a $25K jet and it dies in less than 25 flights you have a jet that cost over $1k per flight. And that doesn't even count all the peripheral costs.

JohnBuckner

My Feedback: (1)

Excellent and precisely my point there are many reasons to choose engines besides just rock bottom dollar made in Timbuctoo.

But suggest anything that is not that bottom dollar and forum political correctness will completely squash that suggestion and especially if it is OS.

John

Cheapie engines are possibly the biggest reason today that far to many folks are lost to the electric only crowd.

jester_s1

I like OS engines in general. I'm not one to bash them for being OS, and I'm not one to normally say that all OS stuff is overpriced. The .46 AX is toward the top of the market price wise for .40 sized engines, but it's well made and also toward the top of the market for quality and factory support. You pay a lot, but you also get a lot.

The reason I made the comment I did on the price of this engine is that I don't see what the money is going toward. Are we paying for simply the fact that it's new, which would make it a rip off, or are we paying for some complicated engineering that went into doing the impossible? I honestly don't know, but on the surface it doesn't look like the engine has any innovative new technology in it or any new patents for solutions to problems that nobody else can solve. If they just took a .65 AX (or similar) and put bearings on both ends of the conrod, then adjusted the ports and compression to make the best power with gas, and then tweaked the carb to run right with gas and fitted a glow driver to run the ignition, then they haven't really done $400 worth of innovating. But if there is some complicated tweak to the head or some new design that causes this engine to be noticeably better than any other gasser in this size, then it's worth whatever the market will pay. That is, at least, until a competitor comes out with a similar product for less.

Gray Beard

My Feedback: (-1)

Jest, you are correct, OS is a bit over priced but they always have been. They also make perhaps the best two stroke engines on the market with great customer service.
This one is probably so over priced due to the low volume of sales that they expect from this new little gasser more then the R&D. Saitos gas engines are the same way, very high dollar with a low volume of sales. They will appeal to a very small crowd of modelers so the price will stay high. I have been waiting for a long time to see someone using the Saito and so far have never seen one in use. I expect the same with this new little OS.
For those wanting to hear reports of this new little engine it would be wise to go into the gas engine forum once in a while to see if there is a thread on it. My smallest gas engine is the RCS 1.40 22cc, these were made by MOKI and I'm sure designed from one of there glow engines. It too was a high dollar engine but filled the gap of small gassers until Zinoah and DLE came out with there 20cc engines.
I'm sure OS is just trying to get into the gas engine field and I like the idea of no ignition and the use of cheap fuel. With the rise of the cost of fuel many people have gone over to electric or gas. I'm one of the few pilots at my field that still use glow but I have a lot of high end YS engines I can't sell. I do get my glow fuel when on sale from $13.00 to $15.00 when it comes up on sale. My last two planes I built are both gassers though. Next builds will be glow powered but one will be a .25.

cocobear

My Feedback: (2)

One of the reasons OS cost mor is that R&D is more expensive than theft. Which will occur shortly I am sure.

Dave

Steve Percifield

My Feedback: (14)

A few years ago Enya invented and tried to market a special glow plug that would convert any engine to run on gasoline. I remember Clarence Lee reporting on it in MAN. But it never hit market here, and disappeared.

jester_s1

I have serious doubts that there is any genuinely new technology in this engine. The only really new thing to hit model engines since the 70's is the CDI ignition, and this one doesn't even have that! It may be a well built, well executed engine, but I really doubt there are any big new designs here for someone else to copy later.

CafeenMan

I agree that there's probably not anything cutting edge about the engine. But I also doubt that porting and all that is automatic either. I'm sure plenty of R&D and prototyping goes into making one of these. If it were really simple then there would be a lot fewer knock-offs out there.

CafeenMan

OK, I've been commenting all this time and missed a basic fact that was mentioned multiple times - this engine has no ignition. To me that means if it runs properly it would be a great engine to own assuming it has more gas-engine-like fuel economy than glow. But doesn't the ignition have a lot to do with that?

Anyway... I just looked at tower and their .95 engine is $30 more than I calculated. I don't know if it's less expensive in a Tower Talk or not but almost without exception anything I ever want from Tower has the same price online as it does in Tower Talk. That used to be a discount flyer. I wonder when that stopped.

If I were building something right now for that size plane I wouldn't hesitate to be the guinea pig.

jester_s1

The ignition has a little to do with that, but that's not the main thing. Do to the chemistry involved, gas has to be mixed a lot leaner than alcohol for max power. I don't recall the exact numbers, but the difference is considerable. Gas also burns slower than alcohol but actually carries more energy per ounce than alcohol, so gas engines are generally ported to make their maximum power at lower RPM to get the most out of it. The reason that gassers normally have a spark ignition is that gas can't work with the catalytic action of a glow plug. One of the perks of methanol is that it will, so way back in the days of magnetos and point ignitions the glow plug and glow engine was a major step forward in power to weight ratio. So what OS has likely done here is supplied an external glow driver to keep the plug hot (I'm speculating) which has been done many times before by tinkerers. A properly timed CDI ignition does help with power and reliability by giving you a precise ignition timing that is pretty close to independent of fuel mix or ambient temperature, which is impossible with a glow plug. So (again, I'm speculating) if it's what I think it is, it will lose a little bit of power to a CDI equipped engine in order to save the weight and added complication of a CDI unit and ignition battery. That could well make it a good option for planes in this size, so I guess we'll see in the next year or so if the RC community agrees.

CafeenMan

I have the Norvel .40 gas and it doesn't require a lighted glow other than to start. I don't know why it works but apparently it does. I only purchased the engine a few months ago and haven't run it. Maybe it's a high compression engine and it's combo of the plug and some diesel action going on or something.

The Tower page only indicates you need a glow starter, but doesn't say onboard glow is necessary.

OK, I just downloaded the manual from Tower and no, onboard glow is not required. It operates just like any other glow engine.

cocobear

My Feedback: (2)

Jester, your doubts are based upon years of design experience or ...... an opinion?