Troube w/ my Hyper 50

[Gunner]

I bought a Tiger 50 in early spring. Bought a brand new OS 50 Hyper. Broke it in on a bench jig and it ran great. Finished with the needle about 1.5 turns out. Mounted the engine on my Tiger. Only flew the Tiger for about 10 minutes, not even a full tank, and the engine died. I'm brand new so all I was doing was hovering. I heard a loud pop in the engine when it died. It was also VERY hot. Hole in the piston. I don't think it was too lean, I think 3 head bolts came loose and allowed it to lean out so much that it overheated. Sent it to Hobby Services, they replaced. Mounted back in my Tiger last night. Decided to break it in on the Tiger. Turned the needle 3 full turns out. Idled great for about half a tank. Decided to rev it up and just get it light on the skids. After another 5 minutes, the engine died. No pop, it just cut off. The engine never got much above 125 degrees (I bought a remote temp gauge). Now it won't start. All bolts are tight, turned the needle in to 2.5 turns. Still wouldn't start. Glow plug is new and heats up. Am I still too rich? I can't believe it won't start at 2.5 when it idled fine at 3. Help. Thx.

[jschief]

I did the same thing with my OS hyper. Did not burn a hole in the piston but wrecked the ring lands. Ran to lean, and the heatsink was loose. I check the heatsink screws now constantly, with overheating the screws expand and work themselves out. I think now you have the engine to rich, I haven't had the other problem. Rebuilt engine works fine now.

[DebianDog]

better check you did not burn a hole in the top of it. It happens all the time.
http://www.helifreak.com/album_mod/upload/0ef7aa742268df115505670b8589ffd9.jpg

[Gunner]

Ddog,
Nice hearing from you again. I don't think I burned a hole in it this time but I'll check. I used my remote temp gauge and checked the temperature regularly while it was idling. Every few minutes after I flew it light on the skids, I checked the temp. It never got hotter than 125 degrees. I still have good compression. I'm guessing that it was running too rich and flooded the engine. But I don't understand how it could run for half a tank at 3 turns out and then just die. I'm going to lean it down to 2.5 turns and idle it again for a tank or so. I hope I can get it started.

[RC-Bearings]

The idle mixture isn't controlled by the main needle. Reset your idle mixture to the middle and set the main needle to 2 turns and try again.

[Gunner]

Paul, I haven't touched the idle mixture screw. The hyper manual basically says to leave that alone. It was set at the factory and 'sealed' with threadlocker. Since I'm just learning, I don't think I need to mess with it right now. I'm planning on setting the main needle to 2.5 turns out once I get the clutch hub tightened. I took out the engine last night, took off the head, and found that there was NOT a hole in the piston. The piston was not even discolored yet and showed no signs of wear. Also, the head bolts were nice and tight. But the clutch hub came loose and when under compression was slipping. That's one reason I couldn't get it started again. I'm hoping once I tighten it up, put on some threadlocker, and remount the engine, it should run fine. It's still not broken in so I want to leave the main needle somewhere around 2.5 turns or more. So I'll start there and then, if not successful, go to 2 turns out. As I said, when it was 3 turns out, it idled great. It only cut off when I revved it up. I couldn't get it started again because the clutch hub began slipping (that's my story and I'm sticking to it). Hopefully I'll have better luck tonight.

[RC-Bearings]

Like I said, it will idle all day regardless of the main needle setting (unless you close it off completely). :D It was cutting off when you revved it because the main needle was far too rich.

[DavidH]

I haven't touched the idle mixture screw. The hyper manual basically says to leave that alone. It was set at the factory and 'sealed' with threadlocker

From page 16 of the OS 50 Hyper instructions

The Mixture ControlScrew (Mixture Control Valve):
For adjusting the mixture strength at part-throttle
and idling speeds, to obtain steady idling and
smooth acceleration to medium speeds. The Mixture
Control Valve has been factory set for the
approximate best result. First, run the engine as
received, and re-adjust the Mixture Control Valve
only when necessary.



Has been factory set for the approximate best result. They center them all up at the factory. They have no idea what fuel your using, what atmospheric conditions your running the motor in. The idle usually has to be adjusted some to get it correct.

That is what re-adjust when nessecary is referring.

Here is the starting settings they are suggesting in the instructions. And from my experience with an OS 50 Hyper. There suggestions are a little on the rich side.

Page 18 of manual
Opening the needle-valve
Firstly, turn the needle clockwise slowly until it
stops. The position it stops is the fully closed
position of the needle-valve. Make note this
position for reference..
Open the needle-valve 1.5 turns.

As Paul suggested, 2 turns open on the main will be prefectly safe. This engine really runs nice at couple clicks less than 1.5 turns when using 30% from my experience.

David

[BarracudaHockey]

2.5 turns is burbling rich for a hyper. Set the top end at 2 turns or if you really worry 2 turns and a couple of clicks.

Pinch the fuel line while its idling, if the motor doesnt speed up in 3 seconds the low end is really rich, what you are doing is cooling off the plug and stalling the motor.

If the motor takes more than 3 seconds, or say 4 or 5 to be safe, turn the low end needle clockwise 1/8 of a turn at a time till it leans out a bit and repeat the pinch test after blipping the throttle, get it to 3 or 4 seconds and you will be pretty darn close. The hyper produces so much power that it relys on the low end needle in mid throttle range more so than other engines. Also the low needle isn't locktited, it may be tight but you can turn it, just make sure you have a properly fitting screw driver when you do it if its tight.

Finally, a model engine needs to be run at operating temperatures to break in correctly, running it slobbering rich isn't doing anything for break in. ABC engines really need to heat up or your damaging the motor, ringed engines like the hyper wont get hurt but you arent doing it any good either.

[Gunner]

Thanks guys. That's what I like about this forum. Plenty of good advice. I'll take it and start adjusting both needles. Right now I need to get the clutch hub tight. It's come loose. Once I get it tightened and dialed in, I'll crank up the engine and adjust the needles. I need to get with DebianDog who lives near me and let him check out the my Tiger.

[Gunner]

DavidH, See you're online. Finally got my Hyper put back together, mounted in my Tiger and flew it this evening. Haven't messed with the low idle needle, just adjusted my throttle curve and throttle hold to get a nice idle. Turned the high end needle in to about 2.5 turns and ran a full tank of fuel through it while just light on the skids. It ran great. On my second tank, I turned the needle in a few more clicks. Still running rich but had enough power to hover at about 5 feet for a full tank. Engine is running great, I want to continue running it rich for a few more tanks then I'll lean it out some. Temp neven got above about 130 degrees. Thanks for your help.

[DavidH]

Glad you got it running. That motor should have no problem at 1.5 turns open on the main.
It will scare you when you get it tuned correctly. The Hyper likes to turn some rpms.

David

[BarracudaHockey]

As long as you dont load the engine excessively, that is doing tic tocs or funnels, lean it out a bit because as I said, you need to get it up to temp to break it in, otherwise your just wasting fuel.

[tailboom]

A good point for any glo engine is to check head bolt torque before you start it. Even new engines sometimes have loose bolts. And after you run it, and got it hot, re- torque those bolts. :thumbup: Be sure to use an off set pattern when re torquing( like a car wheel) ,and don"t strip the threads. The hyper 50 is well known for blowing head seals from loose bolts.

[BarracudaHockey]

A good point for any glo engine is to check head bolt torque before you start it. Even new engines sometimes have loose bolts. And after you run it, and got it hot, re- torque those bolts. :thumbup: Be sure to use an off set pattern when re torquing( like a car wheel) ,and don"t strip the threads. The hyper 50 is well known for blowing head seals from loose bolts.

LOL I've seen it blow more than a head seal from loose bolts.

[Gunner]

Thanks for the advice. My first engine looked just like BH's picture. And I'm convinced it was because 3 head bolts on one side were loose. Engine's repaired and re-installed. Now I check the bolts everytime I refuel. Finally flew my Tiger this weekend. Still breaking the engine in and am about 2 turns out on the needle. I'm flying a full tank and then leaning it out a few clicks. Temp still not getting above 125 degrees. Unfortuneately, in my zest to fly, I got bored with hovering, did some forward flight, practiced landings, and got a little disoriented with a sideways landing. Broke a rotor blade and swash arm. Heli tipped on it's side. I'll have it flying next weekend again. Better spend more time hovering from the side!