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NGH 38CC 4 stroke

Old 01-22-2014, 04:21 PM
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Okey dokes.... another lunchtime down. I did retard the ignition slightly with lengthening the slot as suggested by SJN, and I did get it started with the 'flip-with-a-stick' method for the first time since I have been trying. Did have to put quite a splash of fuel down the gobbler. My electric starter is still not strong enough, I have a stronger one coming!
Ran a good 300ml through it, idle is getting smoother, no screws vibrated out this time(yesterday it rattled a screw loose from my workstand and lost a screw out of the carburettor support!!!). Idling down to 3500rpm with 18x8 wooden 2-blade. Will keep running and running....

For those who have been there and done it.... I hope my regular posts are not too tedious!!! I will probably grow out of it soon


Ohhhh...almost forgot.... cleaned the plug this morning and noticed a small number of cracks across the bend of the electrode, have swapped it out as I think a piece of electrode pinging around on top of the piston would be a bad look!!!!
Alf

Last edited by ALFIEV; 01-22-2014 at 11:05 PM.
Old 01-22-2014, 10:49 PM
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Only trust genuine NGK CM-6 plugs. The clone CM-6 plugs have variable quality.
Old 01-23-2014, 10:50 AM
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Good advice I'm sure. This was the plug that came with the engine, had Rcxl markings on it. Wasn't too worried initially, but when I had a look with a magnifying glass a whole bunch of fracture marks were evident. Might have been alright, sometimes the magnifying glass makes things look worse than they really are, but I decided it wasn't worth the risk.
Old 01-23-2014, 04:08 PM
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I started my ngh 38 today ran it for 1/2 hour xoar 18x8 laminated 6900 rpm idle at 1800 with no problem it ran very nice I am surprised it started by hand very easy shot some fuel in the exhaust turned it over couple of time and wham started right up .
Here is a video http://www.youtube.com/watch?v=gibq9b2DSso

just had to tune the high and low a little.
OK don't make fun of my test stand it works and I have 3 inch screws in a solid door very secure. LOL
It did not back fire at all on 1st start up but I did retard the timing. see i put gaskets on each side of the heat spacer.
I don't think it shakes that bad and after I stopped the motor I checked the play in the crank and had a little no more than any other one and on the zenoah g26 it has up down play too.
I am very excited so far it ran very reliable maybe not the most powerful motor but it ran good.

Last edited by shorte; 01-23-2014 at 04:16 PM.
Old 01-23-2014, 04:34 PM
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Awesome, I am envious that it started so easily and idled so well. Mine takes quite a bit to start, backfires every now and then, and will only idle down to about 3000rpm with a high end rpm of around 7500rpm on a xoar lookalike beechwood 18x8. I had a xoar laminated 18x8 but the trailing edge is chipped now from trying to start this engine earlier on. Might try my xoar laminated 19x8 on it and see if the extra weight and diameter help to get it idling better.
I have also retarded the spark fairly much as far as I can for now.
Old 01-23-2014, 04:50 PM
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I did run it up and got 6900 with the 18x8 laminated so that sound a little low and I leaned it out to see what it could do and set it back to 6800 a little rich.
I used the oven glove to start it you can see it there. I retarded the motor all the way over so was wondering if it is retarded to much now I will move back to 3:00 to try.
I don't think it is to loud I think it is quieter than a stock dle 30 a lower sound. I like the sound.
I think my oil is high. I used 6 0z Pennzoil to 1 gallon for 24 to 1. Used super unleaded gas like 96 octane I think..

Last edited by shorte; 01-23-2014 at 04:59 PM.
Old 01-23-2014, 05:02 PM
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Well.... one difference could be that I am running mine inverted because that's how it has to be in the model. I have leaned up the low speed heaps, probably going to richen up the top end a little tomorow. It does run really nicely in the 6000 - 7000+ rpm range. Also going to the 35:1 mixture as I reckon I've put enough oil through the engine now.
Old 01-23-2014, 05:07 PM
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Yea I just did a quick test will run more tomorrow and retry and this was the 1st run I could probably tune it better but so far very reliable that is a lot to me the plane I am sticking it in is a trainer plane anyway not a 3d plane.
Old 01-23-2014, 07:22 PM
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Shorte; congrats! With gasoline engines, you don't tune for rich break-in. Instead, you use a premix with more oil, as you are doing, and tune normally. It's not like glow engine break-in where you need a richer mixture for break-in.

Looks like you are having instant success!
Old 01-24-2014, 02:39 AM
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Alfiev, if you lean the low speed needle too much, it will also be difficult to start.

Also, do you have a gasket installd on each side of the white plastic spacer ?
Old 01-24-2014, 01:50 PM
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OK I ran it for another hour and set timing at 3:00 and now I get 7000 rpm on a xoar 18x8 laminated. and it still hand starts very easy. After I run it some more will change to 35 to 1 oil to see if it will bring rpm up and check valve clearance.


Ok ran it for 2 hr and 1/4 gallon of gas and the valve gap was way off so I adj. it to .03 and reran the motor and now I get max 6600 rpm but is 10 deg. colder now thicker air.
It will run all day at 1800 rpm.
Any one else running a 18x8 xoar laminated to let me know what max rpm is. The best I seen was 7000 at 60 F. outside.


I have a Xoar 18x8 PJA Series Beechwood Propeller coming will try that

Last edited by shorte; 01-25-2014 at 03:30 AM.
Old 01-25-2014, 07:32 AM
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ran for another hour I am afraid it might shake the trainer apart so I think I might get a zenoah for the trainer.

Last edited by shorte; 01-25-2014 at 01:06 PM.
Old 01-25-2014, 08:36 AM
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Never had that problem, Sure you have tighten the nut enough,
Old 01-25-2014, 09:46 AM
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ran a total of half gallon through it .

Last edited by shorte; 01-25-2014 at 06:43 PM.
Old 01-26-2014, 08:06 AM
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soon ready for maiden. Need to get the switches and batteries in position. Covling, bomb and other tings will be mounted after maiden.

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Old 01-26-2014, 10:51 PM
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nice, but you need a radial to fit inside the cowl
Old 01-27-2014, 10:27 AM
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No, there isn't a gasket. It's interesting isn't it? One parts breakdown printed from an RCUNIVERSE posting shows a gasket on each side of the plastic thermal gasket. The breakdown that comes from NGH with the engine does not show those gaskets, it only shows the thermo gasket.
I might give it a try.
Old 01-27-2014, 10:30 AM
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Looks great Tyor, how did the C.O.G work out with the NGH up front? Did you have to add further weight?
Old 01-27-2014, 02:00 PM
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A radial would been nice this engine dont have gasket on each side of the plastic thermal gasket. But my other engine have

bored because of all the snow here i did some more. mountet the dummy airbrakes and some other dummy parts on the wing. And mounted the covling.

Need alot of weight in the front. I have not put any batteries in yet and the cg is 6cm behind the mark in the manual

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Old 01-27-2014, 04:25 PM
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Finally making a bit of progress with mine. Did manage to flip start it 3 times today, once just on choke, twice I had to manually prime it. Still waiting for my electric starter. High rpm still really good, low rpm down to 2500rpm, but anything below 3000rpm is jumping around like a cat on 'P'. Will run again tomorow. It's definitely running better now I have leaned out the low speed idle some. A lot cleaner too!!!!
Old 02-01-2014, 02:42 PM
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How is everyone's motor running any problems yet.
Thanks
Old 02-01-2014, 03:18 PM
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I starte mine for the first time after I put it in the plane. Had some problems first but that was becouse of a bad ignition battery. Changed the battery and it runs good. Thin I will maiden the val tomorrow
Old 02-01-2014, 06:29 PM
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Nice! keep us updated.
Old 02-01-2014, 08:32 PM
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I just got one of these NGH 38cc engines. I was having trouble getting consistent needle adjustments. First of all what is the starting point for the needle valves is it 1 1/2 turns out for both high and low needles like on any Walbro carbs. Also is the needle closest to the engine intake the low needle with the High needle being closest to the intake air opening. Every time I got the engine to run good and idle through the range. after it stopped the needle settings would be no good after starting it again.

Also would this plane be good for the China Model Products P-40 Warhawk - 1.40 War bird that Nitro Planes Sells. I had a CRRC pro GP26R which runs like top ready to go into this plane but I saw this engine and wanted the four stroke sound.

Last edited by Basil Yousif; 02-01-2014 at 08:37 PM.
Old 02-01-2014, 10:52 PM
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Are the spring on the needle valves tigjt enough? or are the needles turning by then self when the engine is running.

1 3/4 turn out should be a ok starting point for the needles.

I think this engine will be a good match for the CMP P40

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