timmybeetle

Hi,
I recently bought a plane with this motor in it.
Only mine runs only to 6000rpm with a 18 X 10 3 blade Mjezlik, with a menz 18 x10 I got 6400 rpm.
With a Menz 21 x 8 I only reach 5500 rpm, static trust around 6 kg.
Adjust timing and tried all settings of H and L needle but can get more rpm out of it.
My plane weight is around 8-9 kg, and with this setup I need a long run to get airborn, need more trust?
Also I tested with muffler build by former owner and with just a little exhaust pipe, but no divirence there!

grts Hans

Charley

My Feedback: (2)

That's a lot of airplane for a 38cc 4-stroke. Hope it has a lot of wing area.
Have you adjusted the valves? Might make a difference. What fuel/oil mix are you using? Got a good quality plug in it?
See how it flies with a 18X8x2
CR

timmybeetle

Hi,
Offcourse I checked valves clearance, first thing you do.
We have euro 95 and I use synt. oil 1:50.
I have a NGK plug in it.
I will try my 18 x10 prop for flying, with a 19 x 8 I tested but that prop was not good.
Better will be a 18 X12 but I ordered me on, so will see when it arrives!
thanks for help, grts Hans

acdii

You need more oil. Should be 35 to 1 mix, a 50 to 1 is too light on the oil and can cause damage. I personally use 32:1, more oil won't hurt it. At least it isn't like the Saito though at 20 to 1.

timmybeetle

Hello

Strange manual (swiss) say's 1:50 oil mixture, i checked other vendors and they say indeed 1:35.
Ok I will add some oil and see what it does.

thanks grts Hans

acdii

On the 3 blade, reduce it down a size to a 17. The engine is rated for 2 blade at the 18x10 size, so try a 17 x 8 and see if it is any better.

Charley

My Feedback: (2)

How did the Stampe perform with this engine? I suppose you've flown it since the above post. Got any RPM and prop figures? My engine is in the mail so I need to look through my big props.

CR

jet62011@hotmailcom

Try RC specialties for a muffler for your NGH 38 four stroke

Charley

My Feedback: (2)

They show one for the 30cc but not the 38cc. Sent them an inquiry.
CR

jet62011@hotmailcom

Call agape racing and hobby and tak to Jim I by my NGH motors from him and he is vary nice number is 804-723-9910 good luck Gary

Charley

My Feedback: (2)

That's who I ordered my engine from. I've seen some other mufflers via a google search.
Thanks,
CR

Charley

My Feedback: (2)

I received an email from RC Spec. They said no muffler for the 38cc because the exhaust port is not threaded. They tried an adapter but they judged it too thin walled to be threaded for a pipe.

CR

DaveHickey

Just engines in GB has a nice adaptor pipe and muffler for the the 38, or at least did last summer when I ordered mine. D.H.

Charley

My Feedback: (2)

Dave,
Did your adapter come threaded for the header? I ordered what looks to be the same setup from Hobby King but the photo shows a smooth surface on the inside of the adapter. I figured I'd dig up a tap and thread the adapter myself. I think I read somewhere that the thread is 14 X .75 mm.

CR

Charley

My Feedback: (2)

Received my engine last Saturday afternoon. It was double boxed, arrived undamaged. There was a surprise in the documentation, having to do with the gas : oil mix. There's a little sticker on the upper right hand corner of the page attached to this post. It says; break in 20 : 1, regular use 25 : 1. Also says to use synthetic 2 stroke oil. I guess that leaves out my Klotz Beanol.

Among the accessories included with the engine are two Allen wrenches and a 0.1mm feeler gauge for setting the valve lash. I'll check that before I run the engine.

My immediate task it to hunt up one of my test stands. Been raining off and on today, so no rush.

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Charley

My Feedback: (2)

Turns out that the sticker referenced above came from Agape Racing & Hobby, from whom I bought my engine. Jim, the proprietor of Agape, provided the sticker and a two page tip document on how to get the best performance and longevity out of NGH engines, based on his experience with them. Jim says that after a user is certain that his engine is broken in, the factory 35:1 mix can be used. I'm going to follow his instructions.

CR

acdii

I tend to agree with them on the oil mix. When I got my first gas 4 stroke, a Saito FG-11, the mix is 20:1. At that ratio I saw no residue, so I went to 16:1, then saw some oil out the breather. I don't see the NGH being any different, it's not like the 2 strokes where the oil/gas meets the bearings directly on each stroke, but gets to them via blowby. Once I am satisfied that the entire engine is well lubed during break in I then start decreasing the oil content. As long as I can see some oil in the breather still I am content with the mix.

Haven't run either of mine yet, but will as soon as I get a stand build.

mchandrayan

The Saitos petrol engines are different. They do not have ball raced conrods like most other petrol engines and hence require higher percentage of of lubricant in the fuel. NGH comes with ballraced conrods.
However I do agree that some extra oil during initial running is likely to benefit.

mchandrayan

Lovely looking Stampe Doc. Precedent kit I assume?
What's the covering?

jet62011@hotmailcom

How dose the solider hold up to the heat I want to fab up muffler and not sure Thanks for any info Gary

mchandrayan

Silver solder (and I do not mean StaBrite kind of silver solder) will hold the muffler together without any problems. Ordinary electrical solder will melt. I have seen that happen.
Have not used or seen the StaBrite type of silver bearing solder used in this application so not very certain of results one might get using that

Charley

My Feedback: (2)

Quite a few years ago I ran a Saito 1.50 HC 4 stroke on gas with a 16% oil mix. AIR, I used Klotz Super Techniplate oil, which is 20% castor. I know that's a lot of oil but the Saito has a bushed rod. I'm running that engine on glow now but it runs better on CDI.

What with all the controversy about cams & lifters I agree that a little more oil in the mix is good insurance. I don't know what brand oil you're using but Jim at Agape has some favorites, among which is Amsoil Dominator. I found it at my local Carquest so I picked up a quart ($$). I found a couple of the others locally later on.

I have an engine stand coming, also a muffler. When I get all this stuff together I'll run the thing.

CR

timmybeetle

NGH 38

Test update:
Today I tested APC 18X10 on my NGH38, sadly not performance I had hoped for.
RPM 6400-6500 and static trust 5Kg, on datasheet from apc they give this information also.
Put my 18X10 3 blade back rpm 6000 and static trust 5,5Kg.
I will leave it this way, it's to expensive for me to buy all kind of props for testing and get more Satic trust out of it.
Maybe I will test it one day without muffler and just a exhaust pipe.

grts Hans

Charley

My Feedback: (2)

Didn't know you had a muffler on it. It makes sense that it would have one though. Makes one wonder how much restriction it presents to the exhaust flow. My Hobby King muffler was delivered yesterday. I can see through it from end to end but the inside tube is smaller than the inlet opening. I'm near to being ready to start breaking my engine in. I'm going to use the exhaust pipe that came with it but I'll put on the muffler at the end of the break in period and compare the RPM readings. I'll let you know the numbers.

CR

Charley

My Feedback: (2)

Got my new (to me) all metal engine test stand in the mail yesterday. Got it mounted on a board and clamped in my Workmate. So I mounted the GF-38 on the stand, put a prop on it and turned it through. It felt very dry. Squirted some of oil in the cylinder to lube the piston & rings. Put the plug in it and turned it through again. It had no compression. I was going to check the valve lash and and oil the top end anyway so off came the valve cover. There was no clearance at all between the intake valve & its rocker arm! I suspect the intake valve wasn't closing fully, which explains the lack of compression. After setting the valve lash with the feeler gauge
(~ 0.1mm) that came with the engine , it had compression, yippee! So I squirted some oil on the rockers, valves & down the pushrod tubes, then reinstalled the valve cover. I know NGH claims they they test run every engine before it's shipped but now I have my doubts; at least on this particular engine.

With more pre-oiling in mind I took the engine back off the stand , laid it on its side, removed the cam cover and dribbled some oil on the cam & lifters, then buttoned it back up. Put it back on the test stand and flipped it through. Pretty good pop now. I still need to make up a fuel tank and find a suitable battery for the ignition. Making progress . Hopefully I'll be able to run it today.

CR