Andika

psgugrad

My Feedback: (2)

FINALLY...these folks seem to "get it" :

the carb is in the front, WHERE IT BELONGS

the carb bolts to the crankcase like it should (no adapter plate)

the cylinder is steel (not chrome-plated)

it has beam mounts, not standoffs

it has a proper rc-style muffler

the only thing that gives me pause is that I'd like to see a little more meat on the crankcase where the carb bolts thread into...just eyeballing the pics, the carb bolt thread area looks a tad thin IMHO.

BUT...overall they seem to have gotten everything right. OS doesn't seem to be listening...

mpascual

My Feedback: (1)

Here is my first video of the new NGH17cc engine
http://www.youtube.com/watch?v=bAsiSVEEwSM

And some rpm numbers after first hour of bench break-in.


Repsol 95 IO fuel, mixed with Motul 800 2T oil @ 5% (20:1) for the first liter, 4% (25:1) the second one, and then oil can be lowered to 3,3% (30:1) ratio.

Then, some needles tuning , and :
13x8 Master Airscrew K series : 10.900 rpm
14x6 Master Airscrew K series : 10.650 rpm
14x7 APC C2 10.200 rpm
15x8 APC C2 8.700 rpm
15x8 XOAR C07 madera 8.400 rpm.

After the test, the con-rod bushing looks like new.

I know those numbers are nosense for some people on this kind of bench test, and the video des not show anything new. Engines needs to perform on the air mounted on airplanes, but many people wants to know rpm numbers to compare with their current glow engines.


Regards

SkidMan

My Feedback: (17)

mpascual

Thank you for testing those props on the GT17. It is helpful information!
I especially appreciate your taking a look at the connecting rod bushing.

You have more fuel through yours than I do but I am running a 14x6 Master Airscrew K series on mine right now and I'm approaching your RPM on short bursts (I believe I can tune for higher RPM than I am but I don't want to run wide open too long at this point).

Any other comments on how your engine is running?


Paul

SkidMan

My Feedback: (17)

I've been searching through threads to try to find possible comparisons to the power of a Saito 100 based upon comparable props and RPM's. Unfortunately, a lot of the Saito numbers are for props you didn't test - 14x8 and 15x6. However, it looks like they will be similar on the ground, with it looking like GT-17 doing a little better. But the available numbers are all over the place.


Paul

Andika

http://lmgtfy.com/?q=RIMFIRE+PLUGS

http://www.jerry-howell.com/RF-Plugs.html

http://www.modelflight.com/larrydavidson.html

http://www.cncengines.com/orderpage.html

http://www.morrisonandmarvin.com/links.htm

http://woodysengines.ecwid.com/product?310464

http://www.model-engine-plans.com/pa...sparkplugs.htm

DLU

My Feedback: (37)

I have a JBA 15 on a Tiger 60. My issue with that engine is the stock muffler - every seam leaks despite using hi temp gasket seal - also (IMO) muffler is very short coupled to the engine head. It appears someone asked if the NGH 17 addressed the "muffler issue." I did not see any feed back regarding that point. [&o]

Did Michael Chow redesign the muffler? I need another small gasser for my new project the NGH 17 might just do.

Antique

My Feedback: (4)

The Rimfire was made by Paul Knapp in Tempe, Arizona...He was using ME 8s in this scale Rotary Bentley and not having good results...He wanted to clone the old Champion spark plugs, but Champion said no...
Probably some CYA involved there..He made and tested some protptypes, settled on the original Rimfire...
Some of the Rimfires last 500 hours in a converted OS 70, the ME8s lasted 100 hours or less...
The Chinese 1/4 32s are way better than the NGKs.....And cheaper...

a1pcfixer

My Feedback: (7)

See Post #5 where he says "muffler internal plate"
Might mean they put sleeves in?

mpascual

My Feedback: (1)

Current muffler has a internal cone (like OS glow engines) that prevents muffler bending if over tightened. Also reduces the noise (and a little amount of power). When this cone is removed, engine breathe better.
Two halves have one little O'ring seal mounted around the baffle to avoid leakage, but in my first engine does not seal well.
The factory is working hard to supply a very reliable and trouble free engine, and soon will be available a new design pitts style muffler for this engine (welded) .


Regards

TimBle

Thanks Pascual.

It looks like this little engine is already rivalling a O.S. 91FX!
my 91FX is turning a JXF 14x8 plastic prop at 9800rpm.
Fit a bigger 15x8 and it bogs down in the low 8000's. Needs a pipe to bring it back on song with that prop. The NGH 17 looks to be the ticket.
Any chance they can place it on a diet before the final production version is released?

DLU

My Feedback: (37)

Mpascual - thank you.

Your posting is informative and the jpg photo shows what appears to be an improved muffler product.

mpascual

My Feedback: (1)

I don't think so .....
This IS the production version.

Regards

SkidMan

My Feedback: (17)

Put a couple flights on the GT17 and I'm very happy with it. Here are some things I've discovered.

The setting from tweaking the HS needle on the resulted in running lean in the air at higher airspeeds. The engine would rev from idle to WOT nicely but as the plane accelerated it started missing. On the assumption that it might have something to do with the prop unloading a little and running higher RPM's than on the ground, I brought it back down, richened the HS a very small amount, test again, and repeat. Since it seemed to improve with each little adjustment, I kept adjusting a little richer until ran well WOT.

I've got some lower RPM four cycling going (starts when pulling back the throttle through about 33-40% throttle) on right now and I'm leaning the LS a little at a time (while keeping an eye on the high end since they interact).

It likes being started with the electric starter. I understand that hand starting improves as the engine breaks in.

I may try the carb diaphram mod just for yucks when I get a chance.

Paul

DLU

My Feedback: (37)

I made the leap of faith and purchased a NGH from Agape Hobbies. I live on the West Coast - the engine arrived within 3 days of purchase. Talk about great service!!

I do not currently have a 4.8 volt battery in my parts locker. Is there an issue in using a 6 volt battery for bench testing only?

gooseF22

Dont do it. there is voltage limit on it. Instead if you want, the company makes a LIPO version of the ignition that can run on any unregulated 2S pack of Lipo/Ion/A123

I have that one and i just plugged it into the Gear channel and the ignition is powered off the spektrum radio/A123. I put a car switch in line so I can kill motor w/o killing aircraft just like having a separate battery.

If you are running 72Mhz, do not use a common battery. 2.4 ok... interference.


I ran a 15x4 wide on mine and it rips too easily. I kept it from ever leaning out top end, but it easily overrevs it, so I purchased a 15x8 today... will continue break in.

Also if it idles high, richen low end and try again.

Andika

There is no issue, you have to put a voltage regulator output 5V and enjoy.

SkidMan

My Feedback: (17)

It definitely can over-rev a 14x6 and it seems to be able to over-rev and will lean-out at the top end with a 14x8 while WOT in level flight if Idon't richen the HSneedle several hundred RPMrich of peakRPM on the ground.

I've got a 15x8 and a 14x9 3-blade that I'm going to try. I'd guess that the thrust band on this thing is below 9,000 RPM let alone 10,000. I'm going to shoot for something in the 8,000-8,500 WOT on the ground range once the engine is broken in a little further.

Paul

TimBle

its starting to sound like a very impressive little engine

DLU

My Feedback: (37)

I mounted my NGH 17 on the test stand today. After getting the carb primed, the engine fired right up with the use of a standard electric starter. I am using a Master Airscrew three blade 13X8 prop for breakin. With a few minor adjustments to the Low & High needles (lean) - the engine runs very well.

Compaired to the JBA 15, I am very impressed with the initial preformance of NGH 17. The stock muffler has different manifold demensions than the JBA 15 and it still leaks exhaust residue. An application of High temp copper sealent might correct this issue.

grossy2

Anybody done a comparasion between the DLE-20 and this engine??

Cheers

SkidMan

My Feedback: (17)

Ihave a DLE-20 as well. The 20 is a great engine too. Igot both of these engines to drop into existing 60-90 sized airplanes.

The DLE-20 puts out a lot more power, but is physically larger - particularly with the rear carb.

The NGH GT17, with its front carb, dropped right into the existing motor mount spacing from a Saito 100. It will work in situations that would require extensive rework to fit a DLE-20.

Both of my engines are still breaking in but they are both working good.


Paul

garywaters

My Feedback: (1)

I’m building a Hobbistar MK III 60, and I would like to start exploring Gas Engines.

I love the clean look of the NGH-17, and I think it will be a nice installation.

Has this been tried yet?

My next option would be the DLE , but it looks more bulky!

Does anybody know what the Hp is on the NGH-17?

I have been looking at the weight of both 30 oz. without the battery,

12 oz more than the LA 65 that the kit calls for.

This will be my first time for gas and I’m wondering how the vibration is compared to a glow engine.

Should I reinforce the firewall?

chris923

My Feedback: (53)

I see no reason why it won't work. It might have to shift shift the batteries behind the cg.

Chris923

SkidMan

My Feedback: (17)

Garywaters,

The weight issue diminishes a bit when you consider that you can use a smaller fuel tank with a gas engine than you would with a glow. The recommended glow fuel tank is 14oz and you can easily use a 10 or even an 8oz fuel tank with the GT17. Additionally, with the pump built into the carb the fuel tank can be located further from the engine and at a different height. The fueslage of that plane should have plenty of space for the ignition module, etc.. One one plane I moved the fuel tank to under the C.G. of the plane which works out great because then the C.G. doesn't shift as fuel is consumed. On another plane with the DLE-20 Icut a square hole in the bottom of the forward fuselage for easy access to the ignition module etc. and made a rectangular cover that I screwed on.

One of the reasons I purchased a NGH GT17 is that with the beam mounts and front carb it can "drop in" most models designed for glow. Conventional wisdom is to have a firewall that is at least 1/4" thick when running a gas engine. However, as smaller and smaller engines come available I expect to see people becoming more flexible on the firewall thickness.

This gas engine does seem to have more vibration than the Saito 100 4-cycle glow engine that it replaced on one of my models. As a minimum, I recommend making sure that all the glue joints, especially those in front of the wing, are properly glued. It wouldn't hurt to use a little angle stock to reinforce the firewall and other critical intersections.

Enjoy!


Paul