***UPDADTED 03/11/07 Finished building....then...

[HeliBouncer]

Updated 03-11-07
Finally received my tail boom from MTA on Friday and had a chance to install this morning. A Huge THANK YOU goes to RCHELIWORKS.net for taking the extra steps to obtain the tail ball links for the completion of the rebuild. Well this morning I'll start over and see about getting this beautiful bird flying.

PS: finally placed pics in my gallery.




Update 03-02-07
Received my parts from MTA Hobbies today and it looks like the UPS people chucked the box. Opened it all up and found my soon to be new tail boom bent with a complete crease near the middle :( . Called and left a message with MTA, since I'm on the East Coast I'll have to wait for a reply. Also they did not have the tail ball links, so I guess I'll be waiting to fly for a while :dontknow . In another week I'll have a day off :arggg .


UPDATE 02/27
***Okay Ade, double checked the direction of the gyro and it was correct(can never be to sure). I trimmed the ends of the pushrod link per Vance and was able to set the correct amount of positive tail blade pitch to counter act the torque. Now I was noticing the tail had a very high vibration, using the align 600 tail blades which I balanced. Held very well for 1 tank of fuel and during lots of wind (with transmitter correction of course :) ). On the subsequent tank of fuel as I was hovering the tail swayed violently and the tail blade holder shot off with the tail blade. I was able to set her down with minor damage to the tail boom and tail fin. Found out the tail housing sheared off from both ends. Must of been weakend from my first tail strike and the high vibration.

Well replacement parts on the way.
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Started her up just fine, stepped back and increased the throttle then she swung around to the left so hard I broke the tail blades :( Well I followed Rays video on the tail setup where he placed 30mm gap between the tail blade edges for normal mode on flying the heli :arggg: Guess it was too much counter thrust for the torque :?: I could only get 20mm spacing and yup it was still to much... I think I'm gonna just setup the tail to 0 deg pitch and go from there... Any suggestions

401 gyro with 9254 servo.

[SteveL]

Yes start out in HH mode until the rest of the heli is trimed. I usually pint the blades with just a little counter torque. The distance will depend on the ratio. With an EVO I set the arm going to the tail @ 90 degrees

[TMoore]

Ignore Rocket Ray's advice and set the tail up the right way. You need to understand the concept of how it needs to be done not just fold the tail blades and scale a dimension.

The concept to setting up the tail is to have enough pitch in the tail blades so that torque can be counteracted. First of all, you need to know which way the tail is going to make thrust for a given pitch setting. Then you need to determine a starting point for the blades. usually this is just a small amount of pitch to make just enough thrust to keep the nose straight. On a Knight with the blades rotating up into the disk when you look straight down on the tail, the blades should be turning away from the main blades and there should be about 1/32"-1/16" of an inch of pitch in the tail blades. This will get you close.

At this point the tail bellcrank should be at 90 degrees to the output shaft. If it isn't you may have a shaft that is too long and you might need to move the tailrotor hub towards the tailcase.

tnbulldog here in Cookeville just finished a Knight 3D and this had to be done.

The machine flies fine.

TM

[HeliBouncer]

Okay TMoore thanks for the info and will try it today. Thanks for the fast replies Helifreaks.

[HeliBouncer]

tried starting with 0 deg pitch and increasing positive to obtain a balance with the torque of the main blades and now I have the servo pushed all the way back to the boom with no more room to go. Before lift off I can see the nose of the heli ready to swing to the the left just as before :dontknow

Coming from electrics...all I had to do was make 0 degree pitch with the tail blade then dial in heading hold into the transmitter. Worked all of the time. Is it a must to setup non-heading hold in a nitro heli?

[SteveL]

No more then on electric. I usually don't set mine up but I havfe eaten a few tail servos. I know plenty of people that have eaten tail servos even after they set it up. I usually try to get it close. You can't set it up for all conditions anyway. If you set it in normal (Not idle1 or2) then it is off in idle 1 or2 (Main blades are spinning faster so the need less pitch and the tail has more authority). I would recomend getting it close.

BTW Which way is your servo facing? Can you gain room by turning it around?

[BigVanVader]

I run carbon rods on all my helis...its just personal preference...But I think you can cut a little bit of each end of your rod and have enough threads left to put the ball links on and adjust

[Ade_Law]

get the whole model checked over and test flown for you by somebody experienced.

it does sound like the 401 direction is wrong making the model spin rather than hold a heading

Ade

[HeliBouncer]

Vance, I'll give what your saying a shot, this will probably give a little more room to work with to increase the blades angle of attack.

SteveL, I have the servo output shaft away from the tail ( closer to the pod )

Ade, Setting up in normal mode not heading hold, verified the correct direction of servo throw during heading hold prior to starting the flight as to get the normal mode setup correct.

Thanks all helifreaks.

[Rodney]

If you have setup electrics there is no differance in the Nitro. It will work give it some thought and a little time. We will get you thru this.

[Ade_Law]

ok, the arm should be 90degs to the pushrod in normal mode dont use any trim ... ever.

adjust the linkage rod length until the model hovers straight in normal mode. If the nose goes to the right its got too much tail pitch, if the nose goes to the left its not got enough.

the 401 is very tollerant of setup. you dont need to get the mechanical trim in normal model perfect. just in the right ball park.

Ade

[rkeith2]

Ade is on the money ...

[HeliBouncer]

Okay gents, I should be receiving parts in a couple of days. I'll have the day off so I will set up the tail again and adjust until I get a near perfect hover in normal mode. After I'll switch to Heading hold. BTW I don't and won't use any trim on the rudder servo :D

As a side note, the Trex 600 forums has a similar question on the 401 setup and the tail pitch...most referencing no need for the normal mode counter torque with tail pitch :dontknow This setup works fine for my Trex 600 and I don't have a normal mode setup for it, this is why I'm wondering if it is really needed for the Knight 50 :dontknow can't I just setup HH mode, what would be the drawback?

Thanks again in advance

[rkeith2]

Here is the main reason to do it on all ships.

The less work that high speed tail servo has to do, the longer it will last and hopefully not let you down.

When you set linkages up 90 degrees and the length of the control rod at the point where you get good staitionary hover countering the torque, the less the gyro and servo combo have to work (correcting) in hover and standard flight.

If you pick up the heli in HH and and it's holding fine, it's still feeding the correction into the servo to do it versus being somewhat neutral.

[SteveL]

Yes it feeds correction but does not remove the correction unless it sense it is too much. I don't see how this is any harder on the servos but I knew (know) if I posted this it would start a pointless flame war and not help Helibouncer get his heli set up. The truth of the matter is I never set it up in normal in any of my choppers but help a lot of people do it with theirs.

[Ade_Law]

the mechanical centre also affects things like how the tail stops from a high speed piro. if its wrong it will bounce or be very soft.

Ade