UltimateFlyer120

My Feedback: (5)

[quote]ORIGINAL: earlwb

I was out at the flying field recently and flew my NV Engines GX40 RC gas engine on my plane. It was a new plane so it had its maiden flights then too.

I did note that one needs to make sure that no fuel or vent tubing touches the engine, especially the cylinder fins. The cylinder fins act like little Gensu knives and quickly slice through the tubing. I tried some K&S clear tubing on the vent line and it melts on the muffler fitting too. So I used my old standby of using a short length of silicon tubing about two inches long there to take the exhaust heat. Silicon tubing will dissolve in raw gasoline, but it doesn't have a problem with exhaust gasses though, so that should not pose a issue in this case. Besides castor oil is used as well and the silicon tubing works fine with it too. Also after running the engine on the ground for a few minutes, you want to stop the engine and double check the muffler screws and tighten them up as needed.

The 12x4 Master Airscrew propeller I used worked great, the engine didn't have a problem with the prop at all. The plane is intended to fly slow so tooling around at 1/4 to 1/2 throttle is where most of the flying takes place. Also the engine had more than enough power to do unlimited verticals and hovering was at about 1/2 throttle so it can pull out of a hover just fine too. Having the bigger 12 inch prop didn't seem to cause much of a spin up or spin down problem either.

The six ounce fuel tank is working out well. I am not even using 1/2 a tank of fuel to do a ten to 15 minute flight with the plane and engine so far. I also included a short boring video of me flying the plane around while getting used to it. The grass was oddly thick in places, take offs were a bit of a struggle, but not bad, but landings were odd in that the plane seemed to stick like glue as soon as the wheels touched down. So I think maybe I'll have to put some larger diameter thin wheels on it.



Was this plane a Hot Knife?

earlwb

Yes as a matter of fact it is a "Hot Knife" RC stunt plane.

hllywdb

T-Man,
The piston is a flat top, so you can use a flat exacto blade (very carfully) or just use one of those wooden scrapers women use on their nails for a foolproof method. It comes off easily.

earlwb
Glad to see you have it up and running well. I had no issues with throttle response with the 12" prop either. I have no issues with the K&S on the vent line, but it goes up and then back to the tank. Yes, you do need to keep it clear of the motor.

earlwb

I saw on my engine that the plastic tubing had partially melted on the muffler pressure fitting. When the engine is running and the fitting gets hot, the tube can be loose then, and thus less muffler pressure as it is leaking. It was pushing a 100 degrees Farenheit that day too. That may be a factor with the plane and engine being run in a static situation on the ground. The engines do tend to run more hot on the ground than in the air flying around. The tubing right at the fitting looks partially melted and when it cools down looks like it might be held on there well, but when the engine is running and the muffler is nice and hot, it can get loose and leak or more easily slip off then too. One thought it to make a longer metalfitting about one and a half inches long so that the tubing is farther from the hot exhaust gassesright there at the fitting. I might try that later if I get around to it. I had noticed on other engines using Tygon tubing that that first inch or so is where it gets hot enough to melt things. I had seen some engines melt the tubing justpast the fitting, but the Tygon tubing was OK on the fitting itself. Of course we can simply use Viton tubing too, that stuff seems to handle higher temperatures Ok.

Yeah the Gensu knife trick was interesting, I was trying to figure out why the engine wasn't running right, so when I thought I had it going OK, I went to top off the fuel tank and I noticed thatfuel was dribbling out of the refueling tube line. When I looked closer it looked like someone had used a X-acto knife blade and cut some thin cuts into the tubing where it was touching the fins. So after correcting that issue, I needed to readjust the engine again of course.

I mentioned double checking the muffler screws to ensure they are tight (but don't overdo it as they can break or strip out the threads), especially after the engine gets heated up good. I had the muffler come loose and lost a screw. But fortunately one of the RC helicopeter guys was there with a big supply of screws on hand and was kind enough to provide me with one. It uses a M3x12mm screw for the muffler screws. You might want to try M3x13 or M3x14 if you put on lock washers too. It might not hurt to have some spares for when you head off to the flying field, just in case. Not everyone gets lucky and has some RC heli guys there with lots of spares or other RC flyers with spares at the field either.

hsukaria

Unfortunately, my AX-40 muffler bolt holes in the crankcase stripped and I had to tap to the next size up, which is a Standard size. But I did have repeated muffler coming loose after that, so I had to goop some high temp RTV and use lock washers to keep the muffler on.

I also had fuel tubing that looked all "chewed-up", but it turned out that our cat likes to chew on silicone tubing.

earlwb

I have actually flown the engine quite a bit for the past several days. I have almost used up a gallon of fuel on the engine so far, Maybe a quart or so left to go in the fuel container. That is a lot of flying at maybe 3 to 4 ounces a flight too. 15 minutes uses up a little over three ounces of fuel. The engine has worked really well for me too. I have set a throttle curve up on one of the flight modes on the TX so that the throttle is really flat at a little under 1/2 throttle to a little over 1/2 throttle. Thus I have been working on trying to hover the plane. But being so small it isn't that easy to hover when it is a little windy outside. But it has plenty of power to pull out of a hover and the plane doesn't need much air speed to fly anyway.

Here is another crummy video of me playing around and flying the engine and plane. The grass has been a bit of a problem as it is like landing on velcro or like a carrier cable restraint when the plane lands. I can seldom taxi it unless it happens to land on a thin grass patch.

[youtube]http://www.youtube.com/watch?v=hgVW1gLOeGw[/youtube]

Phoenex

My Feedback: (1)

earlwb thanks for all the posts, I wonder what happened to everyone else with this engine? I am thinking about getting this engine and a TowerHobbies Razor to fly pattern and sport. Looks like the engine would need to be mounted upside down. Are there any issues to look out for with the engine being mounted upside down? Iam concerned about getting enough airflow to keep the engine from overheating.

earlwb

There are no issues with being inverted. I have flown plenty of planes with inverted engines and it wasn't a big deal for me. The same caveats that apply to inverted glow engines apply to this engine too.

schulze rocks

Hi Troops,
My GX40 has arrived and is now mounted in the front of my trusty Boomerang 40. The cold run in has been completed and now just waiting on the oil to come in so that I can mix some fuel and commence the regular break in process.

Cheers BJ

Phoenex

My Feedback: (1)

Sounds good, I will be looking forward to your comments and thoughts on this new engine.

Phoenex

My Feedback: (1)

hllywdb What can you tell me about warranty, service and support in the USA? Do they have dealers in the USA? Iam an electric flyer only, but have a lot of help with glow/gas experience, however Iam leary of buying anything without warranty and support in the U.S. from a good solid business.

hllywdb

Hi Phoenex,

Sales, warranty, service, and support are handled by their US distribution at http://www.nvengines.com/ Since starting new production, distribution has been handled by the US arm of the company, rather than rely on private distributors as was done in the past.
I have been dealing with them for a few years and have had great service. There is plenty of info on these forums as to how good their service has been so far. Especially in the 1/2A forums.

earlwb

I have not had an occassion to use NV Engines warranty service yet. But I did buy a few parts from them in the past and the parts came really fast too. I would order Friday night and the parts would show up on Tuesday or Wednesday. So I was impressed with the speed at the time. Of course if you order  out of stock parts, you might have to wait a while as the engines and parts come from Russia of course.

sledge_78

My Feedback: (24)

I recently received my NV 40GX and it appears to work well. Has anyone identified what the factory setting on the low end needle valve? I was adjusting the control arm placement on the carburetor and in doing this the low end needle was completely removed. I replaced it, took a guess at the setting . The engine does run but I know the needle needs to be adjusted. I would like to return it to the factory setting so I can fine tune the high speed needle based on a low end needle being where it is supposed to be.
Any guidance would be appreciated.

Sledge_78

hllywdb

The low end will vary depending on what climate and altitude you are at, as well as with small differences between motors. The factory setting is roughly as follows: Open the carb to full throttle. The low speed should be turned in to where there is about 1mm space between the needle and the fuel tube when viewing from the top.

Hope this helps

triumphman49

My Feedback: (149)

Hi Phoenix,
I've had occasion to use the NV warrenty service for my GX40, and it was flawless. Very satisified as engine returned promptly. Have 2 short runs on it since, but work has kept me pretty busy. It's still not broken in yet . . . mabey I'll get to "fiddle" with it some more this weekend. Fixing up a Rascal clone for flying it.

T-man49 in Al

sledge_78

My Feedback: (24)

Hllwdb,

Thank you. I set the gap to 1MM and will test tomorrow. I was way too wide on the gap so this ma help with the final adjustments. Thanks again

Sledge_78

the pope

Just a word of warning . Follow the instructions about rinsing out the engine before use . I pulled the back plate to find quite an amount of metal shavings even some from the bushed conrod . Pretty poor when you think about it ( I know it can happen with any brand but the only other one I have come across was a TT 10 with an amazing amount of swarf stuck to the conrod but luckily no damage done . I now pull at least the backplate off any new engine . ) , I also ground the muffler to allow the bolts to sit better as someone else here has done . Hopefully will fire mine up tomorrow . Cheers the pope

triumphman49

My Feedback: (149)

Hi All,
Just relaying a little info . . . .
"Hi, Was just wondering if there is anything in the works concerning a larger size of the new NV gas series. "

"It has been designed, but when the production will start is still unknown - too busy at the moment. . . . But the 60 gasser is high priority"

T-man49 in Al
Club Saito #723
Spitfire Bro #19

triumphman49

My Feedback: (149)

Well,
Just finished running out the 1st quart of fuel thru my GX40 today. Got to admit to my ineptness at tuning, and the 1st few runs had left me frustrated. Been running a 11x6 APC & had seen 10,000 on my tach once or twice, but on transition it seemed to continually want to cut out and idle was very high or it would die.
But today, experimented with the "ignitor" and "pinch" test and played with the low needle and somehow wound up seeing top end at 12,000 and an idle down around 2000. My low speed screw is at 2 turns out and high speed needle at 2-3\4 out. Transition is actually pretty good,but upon restart, the 1st attempt to throttle is "laggy", but after that transition smooths out and seems good to me. I have screwed out the idle stop screw so I can kill the engine using the throttle. Will adjust idle when in plane via radio.
Many Thanks go to Alex and Bill as both have been extremely helpful and patient with me. Now to get to work readying a mount for this horse. Working on a Rascal (clone) and hoping a 12x4 or mabey 12x5 prop. We'll see.

psgugrad

My Feedback: (2)

OK...couldn't stand it anymore...ordered mine today with the old style tilt-down muffler to avoid the muffler screw problem. They had a 4th of July 5% off sale. I guess I doesn't take much to get me off the fence! Time to order some oil now...

hllywdb

Hi psgugrad,
I belive the muffler issue was limited to a handfull of early units and has been corrected awhile ago. In any event, yes, start mixing the fuel now as they ship pretty quick

the pope

You might want to jump back on the fence ! The tilt down muffler which came with my engine still has the same prob. Its no drama if you have a dremel to grind away . Wonder why mine came with the tilt down muffler and others don't ? Cheers the pope

earlwb

Yes the old style muffler is a straight out one. The new style is the tilt down type.

hsukaria

Maybe they are mixing them up, but my 5+ year old AX-40 came with the tilt-down. I just recently (3 months ago) bought the straight-out to fit in the new plane cowl.