Max head speed for stock woodies?

[bk.heli.man]

So I am having some vibe issues which I think I have narrowed down to the tail shaft... Last time I tried to take off the 300 had a real bad "roll to the right" causing a blade strike on a brand new set of cf blades, ruining them... Now I am running a ice lite 50 with a wicked motor and a 10 tooth pinion.

I would like to do some testing of the vibes with the woodies so if a blade strike happens again it won't trash another $30 set of blades!

So my question is what should I set the head speed governer to with the stock woodies? Or what is the stock head speed at 75% throttle?

Thanks!

[GSPI]

Stock motor setup if you take inefficiencies into account the 4500kv eflite motor should produce a head speed between 2900 and 2500 rpm so 75% is between 2200 and 1900 rpm.So if you have the stock setup and the Wicked motor which is a 4800kv rating it should produce 3100 and 2750 rpm with 75% being in the 2340 to 2060 rpm range.

With the 10 tooth pinion and the Wicked motor you are running a head speed of 3450 and 3040 rpm with 75% being in the 2590 to 2280 rpm range. So assuming the dynamics of vibration are the same as the original 300X configuration you might need to drop down to a 65% range if there is no governor so that the woodies can maintain the same original designed head speed in the 2250 to 1970 rpm range. Just watch your temperatures on the ESC.

So hopefully this helps but your woodies should be running in the 2200 to 1900 range...

[ahahn]

Originally Posted by bk.heli.man

So I am having some vibe issues which I think I have narrowed down to the tail shaft... Last time I tried to take off the 300 had a real bad "roll to the right" causing a blade strike on a brand new set of cf blades, ruining them... Now I am running a ice lite 50 with a wicked motor and a 10 tooth pinion.

I would like to do some testing of the vibes with the woodies so if a blade strike happens again it won't trash another $30 set of blades!

So my question is what should I set the head speed governer to with the stock woodies? Or what is the stock head speed at 75% throttle?

Thanks!

BeastX recommends taking the main blades off and spooling up to see if there is any swash tilt. The idea is that it is the frequencies up in the tail rotor range and above that cause problems.

I probably can verify that it isn't the mains that cause problems. Early in its life I had a tip over on lift off due to the skid getting caught in the grass. Nothing seemed damaged so I went ahead and spooled up again. I got it a few feet into the air and the heli was shaking like a wet dog, but other than that it was very controllable--the BeastX had no problems. On landing I noticed the main shaft had a slight bend just above the top bearing.

Anyway try the mains off test first. Just keep the rpms reasonable--without the mains you can get a pretty high rpm at WOT, and you don't want to over stress the tail rotor grips.

[bk.heli.man]

Ok thank you very much.. One question I have is, if I am running at a lower head speed which I would assume would be less amp draw, why would you say watch temp on esc? I am still new to this hobby and am still getting an understanding of the whole thing..I don't mean to question hour knowledge or help just trying to understand.
Thanks again!

[koi-fish]

This may sound silly, but check for things you wouldnt expect as well. The other day, I spun mine up without blades after crash repairs and it showed no vibes. Blades on (balanced first), excessive tail wag and vibes. After checking, i realized I had forgotten to put one landing gear fastening screw back on and the beastx was trying to compensate for the resulting vibrations once the bird lifted off.

It didnt cause problems on the ground because the weight of the heli kept the landing gear from vibrating

[Ah Clem]

I increased the headspeed until I got the high frequency vibration, then backed it down a bit until it stopped. I found the RPM could be increased a little more after upgrading to CF main rotor blades.

This is a first generation 300X purchased as soon as they were available in California. It has been fine ever since. and has, conservatively 80-90 flights on it.

[bk.heli.man]

Originally Posted by ahahn

BeastX recommends taking the main blades off and spooling up to see if there is any swash tilt. The idea is that it is the frequencies up in the tail rotor range and above that cause problems.

I probably can verify that it isn't the mains that cause problems. Early in its life I had a tip over on lift off due to the skid getting caught in the grass. Nothing seemed damaged so I went ahead and spooled up again. I got it a few feet into the air and the heli was shaking like a wet dog, but other than that it was very controllable--the BeastX had no problems. On landing I noticed the main shaft had a slight bend just above the top bearing.

Anyway try the mains off test first. Just keep the rpms reasonable--without the mains you can get a pretty high rpm at WOT, and you don't want to over stress the tail rotor grips.

Sorry for not being clear...I have been testing with no blades and looking for a tilt in the swash but haven't noticed any but as it is running (at just about any rpm) I can feel the vibes and have pretty much narrowed it down to the main tail shaft... Going to get one today.. I want to test fly with the woodies so just in case of a mechanical failure (I think my beast may be defective as sometimes it seems to lose connection or "brown out" but that's a whole other issue) I don't trash a set of $30 blades...$13 is much easier to deal with.

Thanks to everybody for their input so far.

[GSPI]

Originally Posted by bk.heli.man

Ok thank you very much.. One question I have is, if I am running at a lower head speed which I would assume would be less amp draw, why would you say watch temp on esc? I am still new to this hobby and am still getting an understanding of the whole thing..I don't mean to question hour knowledge or help just trying to understand.
Thanks again!

Although amp draw is lower there is relative internal resistance that occurs when running things lower than WOT in an ESC from experience. In re-reading your post though, you have a high enough capacity ESC that it might not even be an issue at all. I was thinking off the top of my head the factory ESC in the 25 amp range.

[bk.heli.man]

Originally Posted by GSPI

Although amp draw is lower there is relative internal resistance that occurs when running things lower than WOT in an ESC from experience. In re-reading your post though, you have a high enough capacity ESC that it might not even be an issue at all. I was thinking off the top of my head the factory ESC in the 25 amp range.

Ah ok...thank you very much for clarifying that for me.. I am really hoping I can cure up all the vibes and get this thing back up in the air as it has been grounded since before thanksgiving.

[bk.heli.man]

So my final consensus is that woodies with the wicked motor and a 10 tooth pinion is not an option... Lol! It took a tc of 20% to get down to 2200 rpm according to the castle log... At that low of a tc the heli didn't even have enough power to lift off! I was able to bump it to 45% tc for a headspeed of about 2550 where the heli lifted off for a nice hover!! Looks like all the vibes are gone and I am ready for some carbon blades and a 3000 rpm headspeed. So damn excited to finally get to test out this wicked motor!!! You can bet I'll be out there at the field first thing in the morning!!!

[Richardmid1]

Just an FYI. Stock 9t pinion will give around 3200 in a hover with a fresh pack. 10t will give around 3500rpm. So at 75 throttle with the 9t ide estimate you would be about 2900-3000 rpm. This then is the recommended max for the stock woodies. The reason eflight limited recommend this 75 max tc is because of vibration not because the blades would come apart at a higher tc. The wood blades aren't balanced that well from the manufacturer, however if you balance them (please Google how to properly balance rotor blades first!) then there is no reason not to run them at 100 percent throttle with the stock 9t pinion.

[mixfisto]

Originally Posted by Richardmid1

Just an FYI. Stock 9t pinion will give around 3200 in a hover with a fresh pack. 10t will give around 3500rpm. So at 75 throttle with the 9t ide estimate you would be about 2900-3000 rpm. This then is the recommended max for the stock woodies. The reason eflight limited recommend this 75 max tc is because of vibration not because the blades would come apart at a higher tc. The wood blades aren't balanced that well from the manufacturer, however if you balance them (please Google how to properly balance rotor blades first!) then there is no reason not to run them at 100 percent throttle with the stock 9t pinion.

+1

I run my woodies at 100% (but only when everything is very balanced and running smooth as silk).

[Scotty T]

What's the max head speed that folks are using with carbon fiber blades without having issues?

[mixfisto]

100%

[Richardmid1]

I'm running carbons with the 10t pinion at 100 percent which gives around 3500 with a fresh pack. It can certainly go higher, today's 450's can run upto 4000 and 250's upto 5000 so the 300 should easily manage 4000. Removing the weights from the tail grips and running a stronger tail servo my be required to prevent tail grip bearing problems. Those weights spinning at 16000 rpm equals lots of centrifugal force!