|Jan 03, 2012, 07:19 AM|
It sure has me wondering as to what the holdup is or what the problem is that all of the small gasoline engines are having. Over a year ago, Magnum displayed and announced a .50 size gas engine, Fox displayed and announced a .50 size gas engine, NGH announced and displayed a gas engine too. But none have appeared in the marketplace yet. I don't think that they all had the same problem either, but maybe they did. It can't be the engine size as many years ago the old time engine companies made spark ignition engines as small as a .12 in size. The .19's and .23's were popular sizes too.
Although the pumper Walbro style carb is a nice way to go, you don't really need it. Model Gasoline engines for many years didn't use them. They had to draw fuel just like the glow engines did. So I don't see that pumper carb as a required item. if I had to, I could use a Perry Pump or something like crankcase pressure of some type. Fox and some other companies too, used to have a cast in boss just below the carb on the right side of the engine for drilling and tapping out a hole for timed pressure. Most modern engines have enough crankcase material there to drill and tap for timed pressure too.
Fox way back in 1966 manufactured the .60 and .74 engines with needle bearing rods. But it was more expensive to do it, so they eventually discontinued it. They kept the size of the rod down by using a steel connecting rod, which served as the outer races and the crankpin and gudgeon pin served as the inner races. So yes one could use needle bearings on the rods, but the cost might be too much though, both in needle bearing cost and more precise machining and hardening of the crankpins, gudgeon pins and rod.
They do have small needle bearings one can get though, but it is the other parts needed that make it more expensive.
|Jan 03, 2012, 09:14 AM|
I think old timers didnt force flying envelope like these days flyers.I know Michael has many problems during testing.So last solution is to have a good pump.
|Jan 03, 2012, 04:36 PM|
Seven business days from order to delivery downunder (shipped from China by Mr Xuebin Wang of HiModel). Pretty impressive.
Photo's show what you get straight out of the box. A 4.8 volt NiCad/NiMHi battery is required to power the ignition.
The fuel mix recommended is 20:1, which means 50 mL of oil to 1 Litre of petrol.
Using thinner oil ratios is strongly cautioned against. This engine has a plain bearing conrod which will suffer failure from oil starvation if low ratio blends are used. Also, standard two stroke "garden implement" oils will not do. Full synthetic premium two stroke oil having the specification advised is mandatory. That being a JASO FD rated two stroke oil, available from power sports dealers.
No mention of a minimum petrol octane rating. I have used 98 RON premium with great success in the past in my MVVS (Evo) 26 and will do so with the NGH GT9.
Running report to follow.
|Jan 03, 2012, 11:59 PM|
Mikarrro and fiery, thanks for the videos and photos!
That is really a gorgeous looking engine. It sounds fantastic too with that dustbin muffler. Very impressive!
|Jan 04, 2012, 12:19 AM|
The dustbin silencer looks very well made and has a nice satin black "crackle" finish.
The good news is the spacing is the same as your standard .46 ~ .57 glow engines (ie OS 46 FX) so you exhaust options are plentiful if the dustbin silencer as supplied does not suit.
|Jan 04, 2012, 12:49 AM|
Joined Dec 2011
thank you sir, I trust you all are professional, but please pay attention on below before your flight:
1. GT9cc is same dimension as .56 glow engine, so you use GT9cc just same as a .56 glow engine with all adjustments and installations, but the most important is the part named "Fuel-delivery-system", GT9 will not be worked without this system, so please read the manual for how to install this system and how to use it, and others all like a .56 glow engine.
2. for this system: a glow carb can be used on a glow engine, but cannot be used on a gas engine because the viscosity is different for nitro and petrol, not just for the problem for pressure from crankcase, the fuel-transition is a big problem, Walbro solve it, and now NGH system solve it, others pump tested fail.
3. this NGH system solve the fuel-transition problem, so it can be used on smaller like .36 glow engine with converting to a gas engine.
please contact dealer and me if you get some problems and query, thank you!
|Jan 04, 2012, 08:43 PM|
Joined Jun 2009
I looked at this engine at my LHS, which had it for sale at $219. The engine and components look very nice. I'm intrigued by the separate fuel pump. It should give more flexibility as to where to place it and reduces the bulk of the carby by about half (the typical bulky Walbro-style gas carby's can make it difficult to attach an engine when space is tight).
Perhaps it will also solve the problem faced by many small sized gas engines in cowled situations where fluctuating air pressures cause fuel delivery problems (eg placing the fuel pump on the fuselage side of the fire wall may assist even fuel delivery).
|Jan 06, 2012, 11:50 PM|
I ran my NGH 9 engine today.
* Easy starts
* Well presented with quality fit and finish to all components. Not quite up to the best Japanese and European products, but very close indeed.
* Well thought out engineering details. Split draw bar carb securing stud, 6 bolt head, nice small carb rather than bulky Walbro. Nice filletting for strength where required. Weight also saved where not required.
* Will "drop in" fit as a replacement for most 46~57 Glow engines.
* Remote pump works well. Inclusion of line clamps where tubing slides over pump fittings would be nice though. I will use snippets of medium silicon fuel tubing over the tygon and will add small zip-locks for security.
* Useful power (over 13,500 RPM on a broad blade Taipan 10x6 composite test prop) which puts power up with a good ball raced 40 size glow engine.
* Supplementary instructions clear up preferred oil ratio (20:1) and running in procedure.
* Manual incorrrectly identfies location of low speed needle (LSN). The LSN is where it always is on a standard full fuel metering R/C glow carb. Manual identifies a securing stud (which cannot be moved) as the LSN! I butchered the stud tring to do so before the problem dawned on me. It seems the author of the manual assumed the carb was similar to Walbro in lay out
* Petrol tank and lines amuseingly referred to "oil" tank and lines.
* No exploded parts diagram for the pump unit or carb, which is a complex piece.
* No instructions on use of the RC Excel ignition unit (whick works well).
* Plug cap attachment appears a little tenuous. It's a push on affair. That small plug is delicate.
* My carb high speed needle (HSN) and /or seat seems to have a defect. Fully wound in, and the engine still ran! Out on quarter of a turn and it was too rich to run! It may be debris on the seat, but I think the needle is mis-aligned to the seat, or incorrectly tapered. I will investigate and report further. It was disconcerting seeing the engine run with the HSN wound in to it's stop. I could not set the LSN.
Further report to follow.
|Jan 15, 2012, 04:04 PM|
Have you guys seen this video??? He's using an NGH9 but hes not using the pump. In the very last part of the video you can kinda see the line hooked to the muffler.
In this video, you can clearly see it running on just muffler pressure. His fuel is "gasahol 95" whatever that means but regardless.... the throttle response and overall running is good;
Especially when you compare it with this video WITH the pump. Notice the lower top RPM and sagging at full throttle;
Overall I'm intrigued enough that I ordered an engine from HiModel. Came to about $200 with shipping. Its a few dollars less than what the now defunct Magnum .52 gasser from Hobby People would have cost with shipping and tax(I'm in SoCal).
Here's a video of one of these engines in a plane and actually flying;
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