Can i set the tracking on my blades just idling the heli on my table with 0 pitch? or do i physically have to have the copter in a hover to track my blades properly?</p>

Tracking involves loading the disk. There is no load if the disk is at 0 degrees.

Rafael

Thanks Raf, Now me as a beginner pilot lets hope i can hold her still for a long enough time to get a good visual on my bladesso i can check the tracking haha.

Get it light on the skids. No real need to lift off completely.

Rafael

ok so if Ihave my pitch curve at 50% throttle set to 0 pitch i should be able to take the throttle just a hair over 50% and then check my blade tracking?</p>

just as rafael said, just get it light on the skids. that will be enough to get positive pitch on the blades. most helis will hover at about 3/4 stick, so it will only take just a little bit of throttle to make it light on the skids, or just when it starts to lift off. if you have someone to watch the rotor blades while you do this, it would make it easier. just make sure to use different color tracking tape on each blade so you can see which one is higher or lower, then you can adjust the right blade. make sure to adjust the link only one turn at a time..........

Do not over think it. Leave your curves alone, and go outside and do it. It is not rocket science.

Rafael

I set mine (preliminary) in my garage by putting the heli on our deep freeze with a piece or flat re-bar over the skids. This allows it to get light on the skids without actually being light on the skids. After setting this way it requires very little/none adjustment in the air.

It is not a good idea to strap down (hold down) a helicopter while it is powered up. I can't get to youtube right now, but do a search there for "ground resonance" and look for a video of a Chinook powered up while being tied down. Not a pretty sight.

Rafael

One full turn on theballlink and blades are tracking beautifully. Thanks for the help guys.

I've seen that video and while that is an extreme case of Murphy's Law I can assure you that my little heli is no where near that unstable because I usually keep my hand on underside the boom anyways to keep it from torquing.

http://www.youtube.com/watch?v=RihcJR0zvfM

http://www.youtube.com/watch?v=6vICf8l-KV0

If you insist that ground resonance will not happen to you, then I suggest that you keep any observers at a good safe distance. What you do with your models should only affect you.... Having any part of one's body near a powered-up helicopter is not a good idea.

If you think models are exempt from ground resonance, think again...
[youtube]http://www.youtube.com/watch?v=fln6I2bhk6I[/youtube]

Rafael

Thats funny, I cant see where I ever said model were exempt from Ground Resonance. I did say that when I track my Blade400 though I keep my hand on the boom and I am strong enough to keep it from shaking even just a little.

BTW, that video when he did actually take off for a slit second does it look EXTREAMLY tail heavy?

sorry dood!

have to agree with Raf! if your hand is on the tail boom of a B400 then your face can only be a matter of inches away from the main rotor!!! sooooooooooooo not good!

i had to grab mine in the early days, when i had a brain fart and turned the Tx off before i undid the battery,even though the rotor was nowhere near full rpm i clipped my arm and it took a chunk out!

not even arguable i'm afraid, just don't do it, it's bordering on the stoooopid!

please be safe!

Matty )<+}}}}]@>

I am safe, if fact I wear goggles when I do do it and am underneath the heli except for the split second it takes to see which blade it higher. Tracking blades is probably one of the times when you are in the greatest risk of danger and proper maintance ensures that the chance of blade separation is reduced.

You can track your blades how ever the heck you want to, ultimately the heli need to be airborne so you can SEE what the disk looks like and thats why I like to get them as close as I can in my garage.

I am sorry you had to grab your heli after it was running, hind sight probably would say let it do the chicken dance.

I track my blades by taping the heli securely to the floor with packaging tape. I usually overdo the tape because I'd rather be safe than sorry. I keep a safe distance and would never attempt to hold it with the blades spinning!

Ground resonance? Yes, it exists and I have seen it - the first time when I was unaware of the issue, I throttled up slowly and the heli began to shake like crazy. I was quick enough to throttle back down as soon as it started, and nothing was damaged. However, I have since learned that is is very easy to avoid;

Throttle up slowly to the point where the rotor just starts spinning. Let the blades "catch up" to that throttle speed, and once they do, throttle up quickly to about 50% so that you get past the resonating frequency. If everything is balanced reasonably well, all you get is a slight vibration for a split second as the rotor accelerates through that sweet spot and then it's gone completely. From there you can accelerate slowly again until you've got sufficient positive pitch to check the tracking.

***If the heli begins to shake violently before you get past the resonating frequency, throttle back down quickly - do NOT attempt to accelerate through it!!! You either throttled up too slowly, or maybe your setup just isn't capable of accelerating fast enough...?

Ya, this is kinda the symptoms i'm getting on my Eagle 50. I throttle up, and it begins to shake violently at that sweet spot. I do not throttle past it because i am afraid it will tear itself apart.

As far as I have researched, ground resonance has no effect on 2 bladed rotors because of the see-saw effect, so i can't figure out why it's happening to my heli???I don't think the flybar counts as an exta blade????the 3+ blade rotors on mostrc helis,are built withlead- lag hinges which speedup or slow down the rotoron its path around the mastto compensate for the change in center of gravity after a vibration is encountered.Most helis also employ the use of landing gear or skid dampeners to mitigate the possibiliy of the initial inciting of the vibrations.

The post by rafael shows a heli getting shredded probably because (and this is just a hunch) it is a 3+ blade heli (the real Hughes 500 is a 5 blade), and he might have had a problem with his lead-lags. also, keep in mind the chinhook has two 3 blade rotors. Soooooo, I don't know quite yet if it is possible for a 2 blade to get ground resonance.....yet I am getting the symptoms(either that or it is a bent shaft) of ground resonance even when my heliis not strapped to the ground and is ready to takeoff. When I check my blade tracking, iusually just put a couple bricks on the skids to weigh it down and that worked fine.........no resonance. Then I made a booboo flying one dayand crashed and now I can't get my heli to stop shaking, therefore leading me to doubt ground resonance as a possible cause of vibration.

Feel free to critique me, as you can see by my post #thati am still learning.i try to pay attention to the high-numbered veterans ofRCU.

Last comment: I recommend all of the guys on this forum discussing the ground resonance theory move the discussion to a main post on the beginners forum instead of going uder this guy's blade tracking title. Ifwe start a new postcalled something like "ground resonance" we could probably get a little more outsideadvice from other people searching theforums. Just a thought.

Also heard that Rafael.....you are an engineering major with a math minor......could you give a high school senior some advice in this field. Iam going to Florida State University this fall after I get my instrument rating at my local airport. I am going into engineering (still don't know what kind...I'm leaning toward elecrical??) and want to get a double minor, one in math and one in business. Just want to know how that field looks like. Thanks for the help.

Negative ghost rider...........the pattern is full.

Adios

I think maybe you misunderstood - it (apparently) cannot occur in rigid or semi-rigid 2-blade systems. I don't think our helis fall into that category as their blades are hinged and there is lag as the rotor spools up.

To be safe, I would take time to thoroughly inspect your setup to ensure that there is no balance issue before you proceed. Unless your Eagle is noticeably out of balance, I suspect that it is in fact ground resonance that you're experiencing. Did you make sure to pull your blades straight before spooling up? Have you checked that the blade grips aren't too loose, or too tight? As I said before, do not attempt to throttle through it once it has started, or I'm sure you will destroy your heli.

Keep in mind that I am also fairly new at this... I assume no responsibility if you wreck something!!

Ohhhhhhhhhhhh, Ok nowIgot ya.

Yes, when i spool up, i make sure that my blades are straight. I am pretty sure that my blades are on the right tightness (as far as I know it should be about good enough so that when you flick it lightly, it swings freely, but does not swing all the way around). I heard that tightening them might help lessen the effect of ground resonance???????

As far as balance.....I don't know much about balancing a heli rotor head. Any advice????

Maybe it might be good to make a vid and post it on here to show you what's happening, then maybe you and Rafael could help.
Do you know if I could upload a video onto this website (Iask this b/c most people show vids of their helis through youtube-meaning there is a link to it). To me, it looks like i might be able to....at the bottom of the page there is a "click here to upload images and files button, so Iguess that means vids.

thanks for correcting me, as I am still learning.

You might be able to upload a zipped version of your video, but then some people might be cautious about opening it without a good updated antivirus. The best solution would be to upload it to youtube and then post the link here.

Rafael

Ok, ill try the zipped file, see how it works. I'll try to have it up in a couple of days.

-

Ok, so I tried to upload the compressed zipped file of my heli, but appearantly, only gif/txt/jpg/jpeg/pdf flilesare supported on this website, which means I'm outta luck. What I did find in the video is that my main gear (don't know the technical term) which meshes to the motor, wobbles ever so slightly up and down. So this leads me to believe that it is either the gear or the main shaft wich is bent or deformed in some way. I just need to find out which one so I can replace it. I'm still waiting on a reply from the Exceed RC Support Forum Host, Andy, about how to take out the main shaft. Any advice on this would be greatly appreciated.

So I guess at the end of the day, it might not be ground resonance, although this forum did give me alot of info on helping me determine if that was it. Thanks for all the help guys!!!!!!!!!!

Ho, wait, Igot it.

Ok, I'm gonna upload it to the rcu video portal. Ican upload the vid there if it is under 50MB. My vid was 74MB so I'll cut it a little shorter and try to put it up tomorrow or the next day.

bye

Ok guys, I finally got my shaft out and saw it was bent slightly, so, as Adam on Mithbusters would say "well there's your problem". So i guess its not ground resonance after all.