elabruna2

I'll test my fisrt heli this week and I have a question, how I have to adjust the needle valve, i'm familiar with the process for airplanes but here I cannot put the engine at maximum rpm in my first fly.

Thanks

ChopperMike

Helicopters are more difficult to set than airplanes since you can't just run the engine up to full throttle and set it. It's a combination of how the engine sounds, how much smoke it's emitting, etc. Check the manual for any recommendations first. I highly recommenc breaking the engine in on a test stand since helicopters put such a demand on the engine anyway. This will also make it possible to see about where the needle should be set. The correct needle setting will be somewhat different in the heli unless you can install the same muffler on the engine that it will have in the heli.

If you don't break the engine in first, open the needle 3 turns or so (nice and rich to start) and bring the throttle up and see how it responds. Lean it out a little at a time and re-check. You'll be able to tell when it's close. One thing that is useful is using a Infrared Thermometer to check the temperature. I've read that many times you can be fooled by the way the engine sounds thinking it's too lean when in fact it's too rich. There was an article in Model Aviation a few years back on this and I don't remember what the target temperatures were. Maybe someone else out there knows(I have to dig up that issue). It was somewhere in the neighborhood of 220 degrees F, but like I said I don't remember exactly.

One sign that the engine is too hot (lean or not enough cooling) is when you throttle to idle the engine won't come down to a nice idle right away. Since this is your first heli the exact needle setting isn't crucial as long as it's not too lean since you're going to be low to the ground at first. And you'll get a feel for it as you go.

Hope this helps,

Mike

FLYBOY

My Feedback: (11)

I find it is easier to tie the heli down to a bench and test run it, set the needle valve, make sure the controls are where I want them, make sure everything spools up good and works and tracks right.

If this is your first heli, you definately want to do this. I would also recommend getting help so you don't crash it on your first flight.

I just found another one in town yesterday that has been trying to learn helis by himself and he keeps crashing and having to order parts. The guys I help in town have yet to crash and are all flying well. It makes a difference. Flying a heli that is set up propperly is so much easier and more enjoyable.

ChopperMike

Not a good idea to anchor the heli down unless you anchor it in such a way that the rotor's downwash is not restricted, like on top of a ladder. It's also very dangerous to do this way, on top of a ladder you don't have to worry about taking your head off!

Definitely a good suggestion getting help even if you have to travel some distance to do so. I taught myself 15 or so years ago and although I broke very few parts learning to fly, it was a long learning curve. Trying to fly a heli that is not set up properly is very frustrating. Simulators will help a lot (didn't have them when I started) but you really need to do your homework to set them up correctly. Much easier when someone shows you how. More fun to fly with others and a lot safer too!

Regards,

Mike

FLYBOY

My Feedback: (11)

Been strapping my helis and my students helis down for 20 years. Never seen it as a bad idea or dangerous. Want to explain that one to me?

I usually bolt it to a picknick table, or tie it to the rungs of my extension ladder laying flat on the ground. Never seen or heard anything bad about this before now and as I said, been doing it for 20 years, and was taught this by the proz back then.

ChopperMike

Laying down flat on your back with an outstretched arm to adjust a needle valve, ABSOLUTELY NOT! On a picnic table, maybe, if you're extremely careful that you don't forget (or slip) when you get up. However if you read Ray's Authoritative Helicopter Manual they say if you do use a stand the helicopter needs to be out of ground effect for the adjustments to be accurate, hence the top of a 6 foot ladder. In the book, you'll also notice the guy is wearing a helmet.

Personally I don't think it's necessary if you know how to adjust an engine. Of course, I've been running model engines for over 35 years, helicopters for 17 years. In the 3 days I was at the IRCHA Heli Jamboree in Muncie I never saw a single person set their engines this way.

Hey, do it however you want. Just make sure you're very careful not to become a statistic.


Regards,

Mike

HeliKing

I am newbie,

I am interesting to

HeliKing

Sorry for incomplete post I made previously. I press the submit button instead of the preview one.

I am interested to see how the test stand looks like. Can any body share the picture of it ?

Thanks

ChopperMike

Well, the method recommended in the book I mentioned, Ray's Authoritative Helicopter Manual by Ray Hostetler is using a six foot "A Frame" type ladder. Ray shows in the book a method for making a quick release mount so the heli can be easilly put on and off. I don't have my scanner set up right now or I'd scan the pictures for you. But basically he uses a ladder tall enough to safely work underneath the heli.

Regards,

Mike

HeliKing

Thanks Mike,

When you say to put the engine on the test stand, I though we remove the engine from heli and test it out on the stand as a "solo run". Obviously not.

I am still interesting to have a picture of the stand if any body can help on this.

Regards

ChopperMike

Yeah, I guess we're talking about 2 things here at the same time. My original reply was referring to , as you said, taking the engine out of the heli and running it on a test stand with a regular airplane prop. I reccomend doing this. On some engines it might not be needed as they do not require a long break in, others it's absolutely necessary. The test stand I use is just a piece of wood with a square notch in one end to bolt the engine into with a fuel tank mounted to it. You can also buy universal type test stands at any hobby shop.

The other test stand mentioned was a run up stand which Flyboy said he used to set the engine's needle valve. For a beginner not familiar with the set up of these engines, maybe it's a good idea. I personally don't think it's necessary to do this but then I have a lot of experience with these things.

If you do use a run-up stand just make sure to use every safety precaution you can to prevent injury.

Regards,

Mike

HeliKing

It could be a stupid question for something obvious.

Will it be ok to do the engine break in by just starting the engine (with the engine attached to the heli and simply put the heli on the ground) and leave if with throttle hold for sometime ?


Cheers

FLYBOY

My Feedback: (11)

Heliking, you don't want to put it in idle up and just run it on the ground. You will end up over reving and doing more damage.


Mike, I didn't suggest tieing it down and setting the needle with the blades turning. I guess I just figured everyone would understand that doing that was not a good move. I usually bolt it to the picknick table, run it up, back it off, stop the blades, make adjustments, run it up while standing at a safe dist and also you can run it long enough to break it in without over rev problems. There is no problem doing this. You don't need to be out of ground effect. You can get close, running rich for break in and heli setup, and then when you start flying it, dial it in closer and closer.

To all, never try to set the needle when the blades are spinning. That is just not safe. Tie it down, don't tie it down, you choose. The reason I teach it, especially to new guys that won't get help is that if something is set up wrong, the heli won't go flying off while you figure out what to do. You can move all the controls with the engine running and make sure the disc and tail do the right thing.

As you get more experience, you won't do it any more, but the first one, its not a bad idea.

Remember the post last year about the one that started his and it was at full throttle because he had it backwards. Luckilly he hung on to it and burned it up instead of letting go. If it were tied, he could have let go, got the radio and pulled the throttle back.

You make the choice how you want to do. it.

DustOffUH1

My Feedback: (2)

That was me I searched for the thread, but I guess its gone. I had the throttle servo reversed. Completely fried the clutch.
Joe

ChopperMike

Sorry, Flyboy. I did misunderstand what you were doing. Your method does sound like a good idea. You're basically doing what most pilots do, spooling up and checking the needle, then throttling down and stopping the blades to make the actual adjustment. But since the heli is tied down it's not going anywhere. This would also be a great benefit if say, the trims were way off. I actually had the problem recently of a reversed throttle servo. Fortunately I always have a strong hold of the rotor head when I start so it wasn't a problem except to the clutch lining.

Regards,

Mike