robc57

2 tanks on the ground and half a dozen flights so far on my 38 and I have to say I'm VERY pleased with it, especially considering the price! I retarded the ignition as far as the slots allow which has cured the kick-backs on starting, set the valve clearances to 'about right' from the supplied 10-15 thou and fitted an ASP180 exhaust on a manifold supplied by Just Engines in the UK. On an APC 18*8 I'm getting 1800 idle and 7100 max, easy starting and very quiet running (for a petrol motor). Best of all, compared to my Evolution petrol motors there's virtually no mess to clean up!

DoctorG

Hi Robc.
I am intriqued by the number of tubes you have screwed to the bulkhead. Filler tube plugged maybe and then two others open.?? Just out of pure curiosity how have configured the plumbing.
By the way your findings exactly match mine once the various issues are sorted out.

robc57

Hi Doc, the one with a plug at the bottom of the pic is the filler, next is the tank vent and at the top of the pic is the crankcase breather

ALFIEV

Nice to hear some more positive feedback. I have also had some success with my second NGH GF 38. I have mounted it to a Greatplanes Waco 72" wingspan biplane. I ran 1 litre of run-in mix and now have run 1 litre of general running mix. The ignition is retarded as far as I can file the slots, it is running a XOAR 18x8 beechwood prop at max. rpm 7100, idle rpm down around 1800.

I maidened this last week. Not much chance to fly as we are getting very unsettled weather now. Maiden was awesome. Flew a second flight, also very good. I wanted to attach a video of the maiden, but the person doing the video did a very poor job of it, so I have only included a few still photos. Video to come when the weather allows another day out flying!!

!

AlphaWhisky

I`m still watching here but am otherwise occupied right now and not able to get hands-on involved at this time. Am trying to decide a practical airframe to put around my engine. One option that is available is to build a Dynaflite Decathlon - I have a kit that has been gathering dust under the bench for some years.

How do you guys with experience with this engine feel about this as a viable combination? Will this engine provide enough power for a scale-like performance?

Interested to hear an opinion or two ....

Thanks,

Alan W

ALFIEV

Hey AphaW, not sure about your Decathalon. What engine is it designed to take? Like, if it's a 30cc 2-stroke DLE type frame, then the NGH GF 38 would probably do it. What wingspan? What do you think the final weight might be? There is youtube footage of a GF38 powering a cub. Would that be similiar? Tyor has a GF 38 on a Storch, maybe that's similiar.
For me, I have an ESM 74" wingspan Corsair weighing about 19 lb, the GF 38 is just enough power. As you can see, I also have one fitted to a Greatplanes Waco 72" biplane, probably weighs about 15lb and it has plenty of power for that.

Alf

robc57

mine is in an Acrowot XL, 78" span aerobatic ARTF. It's got good club aero performance, not 3D style, but the engine's only had 6 tanks through it so far.

AlphaWhisky

Seems like the Dynaflite Decathlon may be just about right for this engine. Specs ex Tower Hobbies are :- 89" span, 1237 sq.ins wing area, weight 16lbs and recommend 25-35cc gas engine. I think I`ll take a closer look and see if the engine will fit OK .....

Alan W

DoctorG

Spent some time tinkering with another NGH 38FG bought by a friend. Similar to mine, ignition timing at cira 45deg TDC and lots of vibration until reset to 35deg. I wonder if the ignition module that comes with these engines has the same auto advance (actually auto retard) that the Rcexl modules do? If they don't is that the reason the manufacturer sets the ignition so far ardvanced? Or are these engines particularly low compression ratio...another reason for high advance maybe? Any body have any thoughts on these points?

CH Ignitions

My Feedback: (11)

http://www.rcuniverse.com/forum/gas-...l#post12060369

Hy Guys, I just finish playing around with this engine.
I tried several other carburetors and I got some good and bad results.
Using the prop like in my video...I was never able to pass that RPM.
I went back to the old set-up carb. I did replaced the HI needle with the one from WT257 and improved the throttle response.
I went back and then I took the original and tapered more on the lathe. I got better response on throttle.
You could do the same if you put it in a drill and with a sand paper or good small file to taper it more...but BE CAREFULL !!! does not need much.
To answer DoctorG the ignition module is made for 30BTDC and is like any other regular CDI.
Why they install it 40+ BTDC....only heaven knows.

Timing set with the old fashion way clamp style sensor holder 30BTDC. It is no vibration

Thanks
Adrian

ALFIEV

Yeah, I guess we'd have to ask the designer, Michael Chow, what his thinking was. He did contribute to this thread way back at the beginning, but sadly he left the company so any chance of insights or minor improvements to the engine seem to have departed along with him.
My 2 cents worth, I think the advanced position of the ignition may have to do with an attempt to improve the power/weight ratio. 4-Stroke model aircraft engines seem to be quite heavy for their power output compared with a similiar size 2-stroke.
Certainly there is a drop off in top-end performance with this engine (un-modified in any other way) when the ignition is retarded from factory setting.

Bob Cimarusti

I have a dynaflight super decathalon flying with the ngh38 4 stroke engine and am very happy with the combo. I've had several different engines in the airplane over the years but this is the best one by far. I'm running a xoar 19x8 and getting 6700 rpm with about 2 hrs of run time on the engine. The plane does all the acrobatics that a decathalon is expected to do. I have 3 of these engines and am flying 2 of them so far with no issues. Hope this helps.

CH Ignitions

My Feedback: (11)

Hmmm,

I just got an idea and I do not know why I did not thought about ...since I can...LOL
I will make a native 40BTDC that will allow the engine to run at that 40BTDC and still maintain a good low idle. Have to make a new curve and program the unit.
Well I guess I will not send that engine back tomorrow.
I will keep you informed.

Adrian

DoctorG

Hi Adrian

Good to see that you are hooked into this thread and that you are looking at an example of this engine. Thanks for answering my question about the module and the advance - unfortunately I didn't look back into the thread before posting as your video & earlier posts had already answered the questions!

It's also good to know that you find the pick up lacks 'something' - as that was my view too, but I do not have your knowledge & experience so it's nice to know its not just me being 'fussy'.

Can you post a a bit more detail of the "OLD style clamp sensor" so I can try one on my engine. I think I know what you mean but would like to confirm how the sensor is fixed to the clamp ring.
Cheers
Graham (DoctorG)

CH Ignitions

My Feedback: (11)

Hi Every one,
I made a CDI that is Native 40BTDC to match the engine factory set timing.
Same engine, same prop and gain 300+ RPM.

Here is a video Before with regular CDI with timing reset @ 30BTDC.

https://www.youtube.com/watch?v=TaMxOid_NAQ And here is the same engine running with timing set @ 40 BTDC. I will need to take another video, this does not play all the way ...only half.
But you will be able to see the difference.

http://youtu.be/5atACDs64lQ
Thanks
Adrian

DoctorG

Hi Adrian
40 BTDC comes up as private so won't run.

Would you consider selling a 40BTDC module?

CH Ignitions

My Feedback: (11)

Hi, I think I know why it went private, It will not play all the way, only half.
But for now you can see the difference, I will take another one, and replace this one.
And Yes I will have them for sale. You have a Free one just instal test and report the good or bad.
Till then I will not sell any out.
After you test and report then I will sale them. I know will work ....but I do not want to ..."tut my own horn"
The unit is the standard unit just the curve program is different.
I do not know if is just me with this engine....but I feel like compression is low, also for start you have to flip real fast and brisk to be able to suck the fuel and start.
Start degree on program have a 3-5 BTDC

Thanks
Adrian

robc57

I can see one of these in my future, I've had to retard the ignition on my engine to stop it kicking back when starting which has definitely affected the top end by around 200 rpm.
Adria, what sort of price will they be with shipping to the UK? I take it that they will work as a plug and go replacement using the hall-sensor supplied with the engine?

CH Ignitions

My Feedback: (11)

Hi Rob, price will be the same as my other units, $75 + $6.50 continental USA or $26 World wide.
And will be a direct plug and play.
One thing tho you have to look to see if you have any play in prop drive to crank shaft.
I seen that mine here has 5 degree play.

Thanks
Adrian

DoctorG

I'll take one as well when they are available

luckymacy

Adrian, if I send down a couple of props can you tach them for me. I'd like to compare to what I get on my ngh.

codedlanguage

Salut Adrian !

Noteaza-ma si pe mine, te rog, pentru o aprindere dedicata NGH 38.

Multumesc !

George Hreniuc

PS Guys, don't worry ! It happens that me and Adrian we're talking the same mother tongue.

Mikola

http://www.rcuniverse.com/forum/gas-...l#post12094999

SJN

Looks nice....allmost Enya like ☺

DoctorG

Interesting. When, where, how much? Any specs yet?