I bought a tach about 15 years ago. Wish I would have got it 45 years ago when I was flying speed and racing. You can now use an app on your cell phone for a tach and even a decibal meter. Some are free apps. I of course don't have a cell phone, but am thinking of a mini Ipad maybe just for that purpose.

I am not sure the iPhone App tachs work all that well at higher RPMs. The tachs seem to work for up to a few thousand RPMs, but not higher. I can compare the apps to the regular tachometers, so it was easy to see then.

The DB Meter apps are pretty neat. But I suspect that they have a noise loudness limit. The iPhone app DB meters I have used seem to be limited to about 95db maximum for noise levels. The DB meter apps do not seem to register anything more loud than that. I need to get a regular DB meter to be able to compare though. I haven't done that yet.

Maybe I should skip the Ipad, and just hunt up a DB meter. I would hope the DBs would be less than 95 in any case. Radio Shack used to have them, but I think they may be out of business, or at least they haven't stocked them lately. In this country Radio Shack changed names to the Source, and it doesn't seem to have them either. I guess mail order is best. I wonder what the gas Norvel would perform like with a mousse can muffler or pipe? The transition may change, as they must be a bit more tempermental than a stock muffler.

I've done a lot of engine/prop noise measurements over the years both as an AMA CD and as a club safety officer. Be prepared for noise levels around 100 dBa with a squalling 2-stroke at 9' distance. Remember AMA's "90 at 9" standard?

CR

I have had no time to have fun lately due to work requirements. Will post the difference in the near future. I do have a tach, just no time :( The mufflers that will be tested is/are: stock, compared to Kraft 61, MDS 40.

Would anyone be able to tell me what the low speed needle GX40 factory setting is? I am having issues with the two GX 40's I have. They will not idle reliable any more. It seems odd that both are giving me fits with the same problem. I am unable to get the idle down low enough to land safely. I was getting ready to get the readings with the different mufflers but had the idle problems start. Thanks in advance

I dont know if this is any help but could it be another issue stale fuel , tubing not tied on allowing leaks etc .I know that muffler to tank tube gets pretty hot . The needles are very sensitive , well the high speed one although I have had no issues with the low speed . Good luck from the pope

What would you consider stale fuel? It's about 5 months old. I guess it's worth a try.

Stuff thats not fresh !! ( that was a joke ) My fuel would be older than that and each time I take mine out away she goes . A new batch of fuel wouldnt hurt to try though as would a new plug . Have you had the carb apart to check for crap , dud orings etc . Also are are all the head gaskets - shims still in one piece . i had a heck of a time with my early engine until they started adding and extra one and I did the same and no issue since . Been a while ago I cant even remember the symptoms . Cheers the pope

Considering how little fuel this beast consumes, I may start mixing it up in quart lots!

CR

If I get time tonight will take a look at the head gasket and give the carb a good cleaning. I did forget about the gasket issue. thanks for the reminder.

If you are having the issues with both engines, I would suspect the common element, the fuel, before looking at gaskets or plugs. I mix mine no more than 2 quarts at a time just for that reason. Another factor could be a bit of gum in there if they hadn't run in a bit. In any case running a couple tanks of fresh fuel will probably solve either issue. Good luck!

I only had one glow head gasket and the cylinder gasket looks good. So adding another glow head gasket should hopefully solve the problem?

http://www.rcuniverse.com/forum/atta...mentid=2095592

Mine kept blowing out the gasket . I would take Holywoods advice , he's pretty much the resident expert on these babies . Did you try new fuel ? Cheers

Thanks to seeing all the fun Billsky has had with his NV <locally> I have picked up one myself got a little Plank I have. Picked up the Benol and some 93 octane without the ethanol since I doubt they have a lot of that in Russia. :rolleyes: I found the mix instructions to be... well... different since its 18 ounce oil to 110 ounce of fuel. According to the BeNol bottle, 15% is 19.5 ounces added to a Gal <128 ounces>. I am be splitting hairs, just trying to follow the directions. Oil should set for a week in the fuel... this is getting technical / paranoiac.

I will be reading back over the thread for some lessons learned and such, thanks for the information.
Ron

Lucky you. I can't get gas without ethanol in it here in south TX. I mixed up the gas & Benol, ran it right away. Watch out for hydraulic locks!
Welcome to the fold,

CR

Not lucky... was on Vacation in South Carolina and brought back 5 gal. http://pure-gas.org/index.jsp?stateprov=TX There seem to be a good amount in TX if any of these are close.

Hydrolocks... Check... they do have painful results.

You are right next to a river! Check the marine gas stations, they should not have ethanol in their fuel.

I am hoping to get some help on my new GX .40 BB engine. I bought the engine a while ago and have been trying to get it broken in and running well before I put it in flight. however, I cannot get it to stay running once started. I can't say one specific thing it does, just won't stay running once started. Sometimes, it just cuts out and sometimes it won't take more than idle and that is with the glow starter attached. Definitely, has a hard time running without the glow starter.

I followed the break in instructions to a T. So I don't know what the problem is so I thought I would post this here with some pictures to see what advice anyone would have.

Here are a few facts about the setup. I prefer the look of a cowl and inverted engines. I was told that would be ok, but I might have to start the engine upright with the plane upside down. I am okay with that so I mounted the engine inverted. I think this has changed what would be the normal relationship to the tank. The tank outlets are now about 1-1/4" above the carburetor. So if starting the plane upside down, the carburetor would be 1-1/4" above the tank. Initially, during break in, I was able to get the engine to run both right side up and upside down for extended periods of time, but not well without the glow starter attached. Now I am having a hard time getting it started and once started it only wants to run at about 8k rpm and only with the glow starter. I can't add throttle without it cutting out.

One comment about the pictures is that the extra tubing seen on top of the tank is for the airline from the muffler. I was having trouble with fuel siphoning out of tank so I added the extra line. Might be a bit much though. Also, am using a fuel dot to make refueling easy. Could that be causing a problem? It is acting normally though.
I appreciate any advice that you have. I have about lost patience with this engine even though I hate to give up and loved the idea of the NV engine in the beginning.http://www.rcuniverse.com/forum/atta...mentid=2100005http://www.rcuniverse.com/forum/atta...mentid=2100006http://www.rcuniverse.com/forum/atta...mentid=2100007 Thanks, Joe.

Have you been starting the engine with an electric starter? If so look at post #1158-1159

I suspect you have a fuel system problem. The fuel line to the engine is too long like that with a fuel dot in it. But it may work OK, hard to say though. Plus the fuel dot could be leaking air. The other thing is that the fuel tank setup with the clunk might be letting air get into the fuel line too. Look at the fuel line going to the carb. If you see bubbles then you have a fuel system problem.

I have seen bubbles in the fuel line leading to the carb. So that is helpful. I will try without the fuel dot and see what happens. I have been using an electric starter and looked at those posts. That could also be possible that the rod is bent. thanks for the help. Any thoughts on the level of the fuel tank being a problem or the engine being inverted?

The tank does look pretty high. It could easily flood when upright, which could bend the rod, and starve when flying inverted. I would at least lower the tank to the bottom of the fuselage before farting around with other stuff, as it is pretty easy.

You can shorten that vent line. Just put a vertical loop in it where it enters the fuse to stop the siphoning. Easy to ck the rod. Take the muffler off & check the piston height to be level with the bottom of the exhaust port with the crank at BDC.

CR

Thanks for the help. I will post after I investigate further.