Knight 50 has the shakes when bolted down

[rpd617]

Just ran my knight 50 for the first time today. I had the skids clamped down and only ran the engine no more than 1/4 throttle. When the rotor speed started to speed up (not even a smooth 1/4 stick) the whole thing starts to shake. It is because I have the skids held tight?
I was watching the blades and they looked like they were tracking OK.
I had the pitch curve set so there was 0 pitch from idle to 1/2 stick, but I never got to 1/2 stick, didn't like the shaking.

[WayneBrown]

it's called harmonic resonance. Don't bolt your machine down, EVER...
Use the locator and find someone in your area to help you out.

[rpd617]

I tried it just sitting there and your right it didn't shake around much at all, in fact it started to get light on the skids, so I shut it down.
Thanks

[WayneBrown]

We'll all be more than happy to help you learn long distance if thats what it takes, forgive my short answer earlier, Been a bit under the weather.
What Knight model do you have, what is your experience level, and what is your setup?
If this is your first model helicopter, you will want to tame it way down from the manual's suggested setup.

[rpd617]

I have the Sport 50, I got it used off an auction site. It came with an OS 50 Hyper, 401 gyro and a 9253 tail servo. I added a Futaba 7c radio. My experience is almost none. I flew RC planes about 20 yrs ago and always wanted a heli, but tooooooooo much money.
I saw the Esky honey bees on you tube and my wife got me one for Xmas. I guess I'm hooked now. By the way they are still too much money. I can hover the HB King, sort off.
I'm having fun playing around with the nitro one. Made a set of training gear from dowel rods and wiffle balls. I don't know how long it will be before I work up the nerve to try and fly it.

Rick

[WayneBrown]

Now would be a great time to invest in a simulator, if moneys tight then search for FMS and get a cable to use your transmitter.
Not great, but better than absolutely nothing, and having a few minutes of sim time will mean at least you have a chance.
Have you found anyone in your area to help yet?

[terrybeb]

The cost of the simulator will be the cost of your first crash roughly....look at it that way. Simulators are invaluable in helping you through the rough learning curve.

If you can't afford a simulator, you can't afford to crash, if you can't afford to crash you can't afford to fly.

Maybe too direct but I find it to be true.

[rpd617]

I do have a simulator, Phoenix. I bought it before I got the Knight and the Futaba radio.
It took me a while to figure out how to make a adapter for the Futaba radio to work with Phoenix but I got it working. I still know a couple guys that fly planes but haven't found a heli guy thats local.
Rick

[cudakid03]

I used to zip tie my raptor to a metal patio table to run it in. it always seemed fine on there, until one day when one of the tail grips broke off at the root. I guess there was a harmonic that i couldn't see or hear. Sure scared the crap out of me to see that blade fly off, those tail blades are really movin.

[rpd617]

What do you mean by "tame it down"?
I have been thinking about this and came to the conclusion that you mean to reduce the amount of pitch on the blades. Am I on the right track, or completely confused as usual?
Rick

[BarracudaHockey]

There's lots of ways to "tame down" a heli.

Heavier paddles and or flybar weights are one. Reduced cyclic throws and a conservative pitch curve are the other.

[WayneBrown]

Limit the amount the ail and elev move to make the machine more docile.
Keep the total pitch to 10/-10 and about 45% on the ail and elev in the swash mix menu to start.

[rpd617]

In looking at what I think are called the "mixing arms" they have three holes in them.
Now the ball link is in what I will call hole #1. If I move the ball to say, hole #2, won't the the blade movement, or pitch, be less that it was in hole #1, for the same amount of servo movement? And if hole #3, less that #2 and #1?

http://www.helifreak.com/attachment.php?attachmentid=44590&stc=1&d=1207611930

[WayneBrown]

In looking at what I think are called the "mixing arms" they have three holes in them.
Now the ball link is in what I will call hole #1. If I move the ball to say, hole #2, won't the the blade movement, or pitch, be less that it was in hole #1, for the same amount of servo movement? And if hole #3, less that #2 and #1?

http://www.helifreak.com/attachment.php?attachmentid=44590&stc=1&d=1207611930
I haven't experimented there, you may find it changes the ratios more than you want.

[rpd617]

How many degrees of pitch do you need to fly?
As near as I can tell its looks like now I have about 24% total about 12 below and 12 above. What would the minimum amount of positive you should have?
Thanks
Rick

[WayneBrown]

6 or 7 to hover, 10 is the norm, 12 or better when you are really good. ;)