I have a new Nexus with a OS32 engine. I have only about 3 gallons of fuel through it. I have not blown any glow plugs in this heli. I hear no binding when I spin the blades by hand. The heli does not vibrate in flight either. I have read this forum very thoroughly...and seem to not find a solution yet.

PROBLEM: Heli will not hover very long at half throttle and increased throttle will cause loss of altitude. After heli lands from loss of altitude I can increase to full throttle and it will not hover...and just sit on the ground. I decrease throttle to idle...throttle up again and the process starts over. The problem occurred very abruptly...and worsened quickly. I did notice a weird chirping sound that only occurs at hover throttle or above.

ATTEMPTED SOLUTIONS: Checked throttle settings, checked fuel / gas tank lines, changed fuel brands, ensured muffler ports are open, ensured open tank pressure exhaust through muffler, checked tracking and pitch, verified my carb was varying with my stick movements.

CLOSING: I have never experianced this problem with any of my other helis. I appreciate any comments or solutions. The only thing I can think is my engine is toast??? But I have never toasted an engine...hmmm....could be a first for me?


Thanks,
Chris AA8VL

your engine is going lean and getting hot, richen it up a few clicks ccw and try again, once it gets hot it will not develope power, let it cool and richen it up, continue until it will hover a tank of fuel without losing power, you're trying to get more power than the engine will deliver, hovering is the hardest on the engine, makes it work harder and get hotter. c-yaRon

hotwings is correct. You need to richen the engine to a point where you know its to rich then back it down a little. I use a very unscientific method to gage engine temp. Put your finger on the cylinder where the manufacture's logo is and if you can hold it there 2 seconds its to cold. If it burns your finger in less than 1 second its to hot. Now that my index finger is scared from repeated burns I'm using my other index finger.

if you don't enjoy pain, try getting an infared thermometer. Very usefull tool for helicopter pilots.

Agreed, it's over heating in hover, However.....

This being a OS32, no one mentioned that it is the low speed needle that needs adjusting for hover. The High speed needle should be adjusted for a good climbout, and the LS adjusted for a nice, rich hover.

On the OS32, depending on fuel used, the HS will wind up being somewhere between 1 and 1 1/4 turn open. On the low speed, I adjust it initially to be very rich at idle, as in I let it idle, then pinch the fuel line shut. I want to get about 4-5 seconds of time BEFORE the engine RPM increases from going lean because of the pinched off line. Then I fly it in hover, and will usually have to richen it, (the LS needle), to get the engine temperature happy for hovering.

Now that chirping sound. . Man that could be anything. Not knowing much about your heli, I probably won't be any use here. But, On the shuttle, the starter shaft going into the clutch is a very likely canidate for chirping, what I don't know is wether or not your bird's starter system is simular or not.

Hope this helps!

CeeJay

Ok, I tried adjusting the throttle agiain and no luck. I let the engine cool down and then adjusted throttle. I did this for about 2 tanks of gas which was about 2 hours of time.

Some background...The first 2 1/2 gallons of gas this heli flew like a dream...the last 1/2 gallon is when the problem developed and worsened. I then switched from 20% Cool Heli to 15% Byron to see if it was bad fuel. I have used the Byron in this heli before with good results.

I only adjusted the high speed needle valve. I assume the low speed adj does not need adj as it idles beutifully...or I could be wrong? At full throttle for 3 second this heli looses all power.

PS: It might be smart for me to buy a infrared temp gun. I will go to Lowes today to scout one out. A good operating temp for a OS32 is 190 F at hover throttle???

Thanks in advanced agiain!!!

Sounds to me like something in the clutch or main gearing is loose. The chirping sounds like the clutch slipping on the shaft. Make sure all the bolts are tight. If it is chirping, something is slipping.

Thanks for all the comments!

I have 3 Nexus's...don't ask me why! hehe. So I think I am going to tear down the faulty one and compare it to the other 2 working ones tonight. I guess after 3 gallons of gas it is more than due for a complete teardown and inspection. I will post results soon!

I don't know why I just dont fly my other helis...it is just extremely annoying to know that one has a problem you just cant figure out! I mean these helis are so simple in nature...I should be able to lick my index finger and touch the rotor button and the problem should come to me!!! Wishful thinking I guess!

Have you taken off the carb and check it to see if there is any obstruction in the carb( dirt , etc ). Do you run a fuel filter? How about air bubbles> Are you pulling any air in the line going to the carb. That is what it sounds like to me.

YEP, I burnt it to a crisp. The compression is much less than a newer OS32 I have and the piston color is scorched a very dark brown. I dont know how I burnt this engine up so quick...but it sounds like an infrared thermometer is a good idea to keep on hand!!!

Since I have never had to do maintenence on an engine....what parts do I need to replace on this OS32 MAX SX? Also where is the cheapest place to find the parts?

Thanks,
Chris AA8VL

If it idles "beutifully", as you say, then I place all my bets on the fact that you are running it WAY TOO LEAN on the LS needle.

With seeing the rest of your responses, your going to continue along the path your taking. Such is life. . .

In other words, your not listening to what people are saying. . .

Good luck but most of all Have Fun!

CeeJay

When you get your new engine or rebuild the old one I recommend you add 2 to 3 oz of extra oil to the first gallon fo fuel you use through the engine. Open the high end needle 2+ turns to where the engine will barely run its so rich. Keep it here for the first tank then lean it to about 1 3/4 turns. Once you have 3 to 4 tanks burned richen the bottom needle until the tngine will not idle well and then back it down until it will idle. The OS 32 needs to be rich on the bottom end as it effects the hover settings. If the engine coughs while transitioning from idle to running RPM's this is a good sign that you are in the ball park for the bottom end setting. If it dies while transitioning lean it no more than 1/16th of a turn at a time.

Here is the latest...

I put a new engine in the Nexus. It is still doing the same thing. This is good news...that means my other engine is still good :-)

OK...I am now thinking the clutch is slipping from your earlier posts! I have plenty of lining left. So I guess I will need to do a disassembly and inspection of the clutch components.

I just found out I have a friend that has also had simular problems with a clutch on a Nexus and he used a screwdriver to slightly push out the pads. Is this an OK practice? Or are there better means of accomplishing the same thing?

Again I appreciate all the help!!!

-Chris AA8VL

Nexus clutch issues? Now that is one I have not heard of in a long time (thankfully). All I can say is good luck. I recommend you shim the liner to get a very tight fit between the shoes and liner (somewhere near 0.007 or better). Replace the shoe bolts with high quality bolts if you can find any and pray it works longer than 2 gallons (don't ask how I know).

davidj,

It sounds like this clutch is forever going to give me problems. Is their a optional upgrade solution to this seemingly ongoing problem. OR "What it is...is what it is" I would hate to have to replace linings every couple gallons or so.

Do you have any info on manualy spreading the shoes...my buddy says this is the solution...but I am hessitent on stressing the clutch shoes in this manor...however I would rather spread the shoes than do a tedious lining replacement all the time.

-Chris AA8VL

If you spread the shoe and crack it, your done. Check all the set screws first. If it is chirping, that is a good indication that something is loose. If you can't find anything, clean the clutch good with alcohol or something stronger and see if that works first. If that fails, then replace the lining. I wouldn't stick a screw driver in and start prying on things in there. You will screw it up for good that way. Gaurenteed.

When you spread the shoes you are putting all the stress on the bolts. Thats why I used a thin strip of pop can behind the liner. I used JP weld and glued the shim in and the liner and used the clutch shoe as a spreader. Wrap one or two layers of black electrical tape around the shoe and use big screwdrivers to gently spread the shoes out against the liner to squeeze the excess glue out. After about 10 min pull and rotate the shoe 90 deg and reinsert to get the other excess glue. the two layers of black tape will give you the proper clearence. Once it has dried scrape out any excess glue and then I put some light oil on the shoe and rotate it in the liner and look for high spots and use a scraper to reduce them until I get an even fit.