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NGH 9cc Gasoline Engine - 10/15/2012 6:48 PM   
earlwb


 

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From: Grapevine, TX, USA
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Here are some engine performance numbers I got with the little NGH 9cc gasoline RC engine the other day, when I was test running it.
I was using some Master Airscrew plastic fiber filled propellers and a APC propeller too.

MA  11x6  11,700 RPMS
MA  11x7  11,500
MA  11x8  11,000
APC 11x8  10,700
MA  12x6   9,800

Engine low speed idle was pretty good down to around 2400 rpms, but going lower usually results in a slow cycling surge like effect occuring where the RPMs increase and decrease, up and down.


Using a Master Airscrew 11x6 prop.

Master Airscrew 11x7 prop

Master ASirscrew 11x8 prop

Using a APC 11x8 prop

and a Master Airscrew 12x6 prop

engine idle speed with a MA 11x7 prop

Using a MA 11x7 prop shows the engine running pretty decent on temperatures too. Ambient temperature was about 82 degrees F at the time. Not like when it is 110 degrees F ambient temperatures during the summer. This measurement is at the base of the spark plug on the head right there. Off the back of the head of the engine the temps are around 225 degrees F.

 



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RE: NGH 9cc Gasoline Engine - 10/15/2012 7:40 PM   
Seamus OLeprosy



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Status: offline 		Did you have trouble setting it up? Hobby King started selling them for $128 and I have one on the way to me.
But there are reports that they are difficult to get running reliably.


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RE: NGH 9cc Gasoline Engine - 10/15/2012 9:26 PM   
earlwb


 

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Status: offline 		It was a hassle at first as I wasn't used to running a gasoline engine at the time.

But the efforts of several other people and myself came up with this list of things to do or check.

1. The motor is not a plug and play from the box, you will need to do some work and buy some more items.
2. First is I would take off the back plate of the motor and replace the threaded pressure nipple with a larger one. 8/32 fitting from Dubro seems to be the popular one and this will require drilling and re-tapping.  I also replaced the pump fuel fitting with a larger 8/32 fitting too.
3. The pump/regulator should really be pulled apart and serviced with a Walbro K20-WAT kit, this will replace the diaphragms, gaskets, metering lever and plunger needle. I would also have a look at the faces of the unit where the gaskets seal on and see if they are smooth. If not then smooth them off by putting some cutting paste on a sheet of glass and run the face over it in a gentle figure eight motion to bring the surface smooth and level. I used a fine stone at first and while this worked it created a slight curve in the face which I later had to remove. The new gasket and diaphragm will handle the newer fuels and not get out of shape quickly.  I like using the white Teflon pump diaphragm but trhe blue diaphragm works fairly well too. The Black diapghragm also works good in comparison to the OEM rubber parts.  You may be able to forgo the smoothing operation, it depends on how well the pump/regulator works for you and how much it leaks or seeps when the engine is running.
4. If you are really into servicing the pump/regulator then you can also replace the metering spring with a Walbro WYJ 98-3160-7.  The spring is a little more short and increases the fuel pressure to the engine. If you mount the pump/regulator really close to the engine, you may not needed it though.
5. Some people have used 1/8th Viton tubing for the pulse line to minimise loss of pulse to the pump/regulator. I have seen some use a brass tube with tygon at each end to do the same thing, not a bad idea but you would want the tubing to be barbed. I had good luck just using 1/8 inch Tygon tubing though.
6. When putting the motor on the test stand, or plane, have the pump/regulator on some sort of foam mount to absorb vibration. It has to be positioned as close as you can to the carb, allowing for the exhaust pipe, 80mm is the recommended maximum distance.
7. Fuel tank can be where ever you find space and height is not an issue.
8. When fitting the prop, be sure the collar which has the earth magnet for the hall sensor is in the correct position. It can be rotated and fitted back in place 180 degrees out. I am sure all of us have made the mistake but it is easy to check, rotate engine until tdc and sensor will be near the magnet.
9. Make sure all your fuel connections are air tight and secure.
10. Fuel mix is 20:1 don’t even think about 25:1.  I also use a really good oil such as Amsoil Saber Pro 100:1 or Stihl Ultra oils in my engines.
11. Without the new spring on the pump/regulator my needle settings are LSN a touch more than 2 1/2 HSN just under 1. When you first start it I would put the LSN at 3 and the HSN at 1 ½ .   Depending on your mods, the standard LSN needle setting is six turns out and the high speed is 1 and half turns out. Idle is typically 1/2 open of the carb. But with the mods you may have it closer to being closed though.
12. Be sure you are only supplying the correct voltage to the ignition unit 4.8v.  The CDI using is rated for 6.0v maximum and they really mean it. A five cell Nicad or NMH pack exceeds 6.0v when fully charged as do LiPo packs or LiFe packs. Anyway a 4 cell 4.8v battery pack works quite well any extra voltage won't gain anything at all.
 
13. Before starting with the ignition off rock the prop back and forth to pump fuel up to the carb. Start the motor with about ¼ of the barrel open. If it does not start straight away you may need to open it more to get more air into the motor. Starter motor required.
14. Adjust your needles to best setting. I have so far with an engine that is still running in, achieved 2500 to 10500 rpm with a 10.5x6 APC prop
15. Motor runs nicely but does sputter a bit and definitely spits fuel out as the carb is very basic and only just does the job. Work in progress with improving the performance.
16. Some people had problems trying to run it inverted and that may be the carburetor design. So it doesn't like that so far.

On my engines I wound up with idle speed being with the carb barrel about 1/2 open. So your results could vary on that.

The OEM rubber diaphragms in the pump/regulator may work much better using gasolines outside of the USA. Here in the USA they use ethanol in the fuel along with a number of other unpronounceable chemicals too. Here in the USA the SEF or Tru-Fuel premix gasolines don't deteriorate the rubber parts as fast and it may not need replacing then. The Chinese didn't have our USA gasolines to use in the engines so they wouldn't have likely encountered the problem. With USA pump gasoline the rubber parts get soft and stretch out and thus quit working on one.




< Message edited by earlwb -- 10/16/2012 2:19 AM >

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RE: NGH 9cc Gasoline Engine - 10/15/2012 9:42 PM   
earlwb


 

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Status: offline 		Here is one of my little 9cc engines mounted on a Escapade .40 RC plane.







and here is a video clip I made showing it flying the plane too

http://www.youtube.com/watch?v=0HkMYRiLhPQ


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RE: NGH 9cc Gasoline Engine - 10/15/2012 9:46 PM   
Seamus OLeprosy



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RE: NGH 9cc Gasoline Engine - 10/15/2012 11:51 PM   
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RE: NGH 9cc Gasoline Engine - 10/16/2012 12:19 PM   
earlwb


 

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Here is a pic of the spring and metering lever (whatever they call it). The 98-3160 spring is on the left, The Walbro steel lever is on the left. The OEM spring and soft aluminum lever is on the right.



The Walbro lever sits higher in the carb bowl too.



This pic shows the larger 8x32 fuel fittings in use on the engine in place of the smaller OEM fittings. The Dubro fittings also have dual barbs for gripping the fuel tubing better too. I needed to shave a little bit off the fittings so that they didn't protrude into the engine too far and also for the fuel pump cover too.











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RE: NGH 9cc Gasoline Engine - 11/29/2012 4:06 PM   
afilho


 

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Status: offline 		Ok, guys, this thread has been very usefull to me, but i've watched a lot of videos of people using this engine withou the pump and on one of the videos the backplate doesn't even have a fitting on it, i'll try without the pump as im getting air bubbles in my fuel lines and i've double checked everything and i can only guess the pump is making them. here is some videos let me know what you guys think.

http://www.youtube.com/watch?v=lnPbxfvq8v4

http://www.youtube.com/watch?feature=endscreen&NR=1&v=vzU-VI5RcSE

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RE: NGH 9cc Gasoline Engine - 11/30/2012 2:23 AM   
earlwb


 

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Status: offline 		In my case the pump regulator is very sensitive to engine vibrations and the vibrations seem to cause the gasoline to vaporize and that looks like air bubbles but it is really gas vapor bubbles. So if you look at my engines the pump regulator sits on a foam padded shelf and is loosely held in place with a length of Velcro tape. That isolates it from the engine vibration fairly well and then the pump regulator tends to work well. 

The other caveat is you have to work the pump around at different angles to get the air bubbles inside out of it. I usually move the plane around at different angles working the air bubbles out. I usually only need to do this for the first engine run of the day, after that it is filled up with fuel good and no air in the cavities inside.  But I also started using a third fill line to the fuel tank so I don't disturb the fuel line itself and introduce air bubbles in it while refueling the plane. These pesky air bubbles from when the pump regulator is empty at first and filling up as the engine is runnign can be a hassle sometimes.

Now several people have run the engines without a pump regulator. We actually have one fellow at our club field who is doing just that same thing too. Unless it is on a test stand, you really need at least muffler pressure for flying in a airplane.  I also think a couple of guys used the Cline regulator along with a Perry pump too.



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RE: NGH 9cc Gasoline Engine - 12/18/2012 1:25 PM   
earlwb


 

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Status: offline 		Here is the engine that I did the rpm checks on,  as mounted in my low wing sport pattern plane.  The plane is a large .45 size glow engine plane with a 59 inch wing span. Foam core wings and a balsa built up fuselage as well as painted, no plastic covering.  I forgot to mention that in the first post I used a Tower Hobbies .46 engine muffler on the NGH 9cc engine. It is more quiet than the stock OEM muffer. The Escapade .40 NGH 9cc engine is using a OS Powerbox muffler for a OS .46AX type of engine.





Here is the Escapade ,40 and my low wing .45 plane side by side.






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RE: NGH 9cc Gasoline Engine - 5/29/2013 1:24 AM   
pulse60


 

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Status: offline 		Hi I have been playing with the ngh for some time now havent quiet got all the bugs out but what i have found is that this engine likes 92 octane fuel at best whell i only have 3 types to chose in au but i firs ran the engine on regular unleded wich is 92 octaine thinking i mite get more power from a higher octane i went to 98 with bad results fuel kept vaperising badly i use full sinthetic moter cross race oil at 25:1 runs fine on this

with the idel screw i tuned mine withthe screw inside the throtle lever as the one in the manual is tight to turn its out about one full turn im not shore what the hi is out as i just turn it back untill the engine hits like a powerband i need to do some rpm tests but fine it works best with a 10/6 masterairscrew prop let you guys know when i do the tests 


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