rriss

I bought a heli off this site that was "brand new, never been flown". I got it home and tried to dial in the engine (os .32). After about 20 min. of trying, I took it home and took the engine apart....blown. Piston melted. Ordered a new OS .37 and took it out to try it out. Would not get off the ground at recommended rich setting, leaned it out a few clicks, hovered great for 3 minutes and lost power and came down. Would not start again. Took it home and broke it down.....piston melted. Few thoughts.
I noticed a good amount of fuel leaking from a small hole in tank stopper....would that lean it out enough to fry the engine?
I took the whole heli apart to check bearings....main mast is pretty tight to spin by hand. Would that make the engine work too hard and overheat?
Would a tuned pipe...not sure of brand....have anything to do with it?
Wife is telling me I have to quit the hobby if I need a new heli. I need help.
Thank You

Hawk Sport
OS .32/.37
Cool Power 15%

w.pasman

any leak will cause engine tuning problems and hot runs.
But usually a first hot run will not cause a major engine breakdown. And melted pistons are really very weird. Please post a photo of these melted pistons.

WhtBronco

You have to be running very lean to overheat enough to melt a piston, especially in a short period of time. You don't need a new heli, but maybe some parts. The main mast will not spin really easily, but if you spin the rotor blades by hand they should not stop immediately. Bascailly it should be fairly easy to spin. If this heli was assembled when you purchased it, you might consider taking it apart and reassembling it, atleast the the head assembly down the main shaft to the main gear. This way you can ensure each piece is installed properly and rotates freely.

You need to make sure that your fuel system has no leaks, period. If the stopper is leaking then the pressure from the exhaust will escape there and assist with fuel flow to the carb which will cause a lean run.

BTW, my wife finally gave up losing her patience with her my models. I am just limited to how many I can purchase per year now. Maintenance is not too much of an issue generally. The problem is they don't understand the addiction, LOL. Good luck with her.

BarracudaHockey

My Feedback: (11)

You're wife is loosing patients? I hope she's not a doctor!

rriss

Thanks so much for the replies.....pistons never "melted" by definition I suppose, but scored so bad that compression was lost. First .32 shelled the bearing and fragments got into the combustion chamber....made a mess. Second .37 scored the piston and sleeve and welded the ring in the ring groove flush with the piston. That was after 3 minutes of hovering, that's why I threw out so many possibilities. Never heard of that happening from one lean run. I'll probably replace the one-way bearing and gear.....it feels VERY tight, and already ordered new fuel tank. Might send engine to OS to see if they will warranty the repair. Otherwise, I'd hate to throw a third engine in it only to have it happen again. I'll try to post some pictures of the engines later.

RevGQ

First, buying any RC equipment second hand off the net is a crap shoot. Build your wife's confidence by doing your home-work first before purchasing. We men must admit that this is not an inexpensive hobby and should be willing to be accountable for the monies we invest.
Most wives love it when we are passionate about something, and this hobby is no exception. My wife has commented that she thinks that I am the most patient man she has ever known, after seeing me on many occassions start working on a building project at six in the morning, and still there twenty four hours latter.

Helis are tuff, and I would suggest that you build one from ARF are kit and spend the extra dollars to purchase some to the good heli books. Do the research and put in the time and you won't be dissapointed with your efforts. Hey, I am a Pastor, so what else would you expect me to say. Blessings.

Helijack

My wife feels much happier knowing I am at the field or in the shop over dumping money in a bar or chasing wild women. Damn heli's cost more to maintain than a good woman.
Jack

johnboyrc

Personally, If I bought a used heli, I would tear it down and build it back up. That way you know the conditions of the parts and can replace suspect parts right away.
Buying a heli that was put together already, I would still tear it down unless I knew the builder's building skills.

WhtBronco

Uhh, nope. My helis cost me a little sure, but my wife costs me all the rest. Wait I have to check with her before I buy any R/C stuff since she handles the money.

PlaneHeli

Frying two engines in quick succesion. What fuel are you using. Is there ANY oil in it. Most guys (and engine manufaturers rcommend between 18-20% oil. Unless its a known brand YOU bought. Dump it and buy some recomended fuel with oil added.
If you bought it second hand it may not have any oil mixed in yet.

Im not sure if the tight mast would fry the engines so quickly, but it certainly shouldnt be that tight.

Sorry, just noticed your using coolpower. So oil should be added already.

Coupe420

i keep reading over that first post here and i still havent heard anything about break-in. Did they? Did you? i could see that happening to a brand new engine with no break-in. if u did break them in correctly disregard this, if you only installed em and went straight to flying i wouldnt be suprised with the results you describe.



Keep breathin them fumes

Coupe

heli_Rod

The mast definately should not be tight. It should spin freely when you spin it by hand and let it coast to a stop. Bearings that are bad "usually" sound rough or click. Gear mesh might also be a problem. If mesh is too tight it will rob power, as well as wear the gears prematurely. Too loose is also bad. You can check it with a piece of paper the width of the gear by running it through the gears by hand.. It should show crisp bends, but no cuts or rounded bends. If it doesn't, readjust the the mesh by moving the engine in it's mounts.

You didn't mention the rotor head speed. It is also possible that the main blade pitch is set to low to sustain a hover. It should hover at slightly above half stick with around 4-5 degrees positive pitch. Even a rich running engine should attain a hover. The last thing you want to do is run lean whether you're breaking an engine or not! Get a good brand of fuel with at least 15% nitro and a minimum of 18% oil. I personally use Wildcat 15% and it has never caused a problem.

The last thing, what brand and model is your heli. Knowing it's construction may help diagnois problems.

rriss

The heli is a Hawk Sport. I was told the first engine was broke-in. I was in the process of breaking in the new one when it quit running. When you turn the mast by hand it clicks and pops quite a bit and also grabs pretty good every couple revolutions. I will be replacing all the bearings and gears to be safe....cheap fix. Pitch was set at 5* half stick and 10* max so I don't think head speed was the problem. I just think between the tight mast and leaking fuel at the tank it just leaned out and overheated.

FLYBOY

My Feedback: (11)

What are you breaking these engines in with? Sand? If you ruined 2 brand new engines in a row, you need help bad! Find someone who knows what they are doing and get some help. DO NOT PROCEED ON YOUR OWN. Your wife has a point! You need help from someone that knows what is going on. I have been flying for over 30 years and have never seen someone ruin 2 engines in a row. Your not doing something right. I wouldn't start another without help from someone right there with you. You will ruin another one.

rriss

Not for nothing but I have been flying myself for about 15 years. That's why I posted my question here. In 15 years I have never seen this problem either. Thank you.

FLYBOY

My Feedback: (11)

Oh, sorry, I just figured if you shelled 2 new engines in a row you hadn't run one before. That is quite unusual, and with your descriptions, it came across as you hadn't ever run one.

BarracudaHockey

My Feedback: (11)

You cant tune a heli engine like an airplane engine.
http://www.raptortechnique.com has two articles for beginner and advanced engine tuning, I respectfully suggest you read both.

rriss

This is my third nitro heli....just never had this brand and wasn't sure how tight the mechanics normally are on it. I was told it was brand new and wanted to rule the heli out as the problem and after tearing it down to almost nothing, I figured there is way to much tension and noise (clicking) coming from the bearings and gear mesh, mostly on the tail rotor drive gear. I am pretty sure I just got taken for a ride and got a bum deal from someone on this site and need to fix what I have before I ruin another motor. I started running the engine VERY rich....wouldn't even hover. And after about 2 minutes running at each setting, would lean it out one click and try again. Finally hit the settling that would allow hover, and after 5 minutes of hovering, overheated and lost power, and wouldn't start again.

FLYBOY

My Feedback: (11)

Either you way over stated the problem, or you have a problem. You said in both cased that the piston melted. It would take a lot more heat to melt a piston in one run than your engine will produce from binding parts or a lean run. I run engines probably leaner than most would when I race and I have ruined some engines over time, but never, never in one run.

Like I said before, if you have 15 years exp with engines, you know how rare that is. I would still have a second set of eyes that knows the heli have a look and see what you are missing. Maybe check your fuel and make sure it isn't 90% instead of 15. Just kidding on that but it sounds like a serious problem that you have. I would love to see pictures of what you call melted.

Crash Bandicoot

Yeah I strongly agree with that. I am not risking my health due to a potential sloppy inexperienced builder.

wildchild45177

My Feedback: (11)

Can't help with the heli problem, but can help with the wife problem. When my wife complained about my planes, and time spent flying, I said, OK I'll sell them all off, and use the money to go bar hopping, and chasing wild women. (she knows this is what I did before I got together with her, now I don't even drink) She has not had any more complaints about my hobby.

Bob

reaaz

"took the whole heli apart to check bearings....main mast is pretty tight to spin by hand. Would that make the engine work too hard and overheat?"

by that statment alone... Your drive system & bearings may be artifically loading up the engine... result instant overheating. the rotor head should NOT feel like there is any drag in it, rather it should turn quite easily. Also check the tail drive system the excess drag may be coming from that. Check all bearings/ shafts for misalignment.

But all in all, somewhere something is locking up that drive system. troubleshoot that, get that sound! Only then proceed to the engine & fuel system.

reaaz

one other thing i thought off, assuming you have a good engine fan.. does the shroud completely direct the flow over the engine?

pipercub123

My Feedback: (1)

Be a man and tell your wife who the boss is. She probably spends more money on shoes and clothes without your knowledge.