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rdsvark
Hover Master
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Joined: 16 Jul 2012
Posts: 19
Location: SURREY UK

PostPosted: Sat May 18, 2013 10:47 pm
PostPost subject: Setting pitch on blades
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Hi,
Slight problems with setting positive and negative pitch on blades. Have 10+ on high stick but only 8- ve on low.

Have set servo arms at 90 degrees, swashplate is level at mid, high and low stick using a leveller (Have a linear pitch curve)

Have set blades at 0 degree at mid stick, and 10+ degree on high stick. Used Swash mix to alter settings.

But on low stick I have only got 8- negative instead of 10.

I have read somewhere that I should either lift or lower the sawshplate in order to correct this, but if I do this doesnt it change the positive pitch again?
I only use 2 degree negative at low throttle as I am still learning, so does it make any difference anyway...

Thanks
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pjdog
Extreme 3D
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Joined: 12 Jan 2010
Posts: 2073
Location: Hudson, Florida, USA

PostPosted: Sat May 18, 2013 11:52 pm
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The wash out control arms (2) should also be level at mid-stick. I have the same problem today with the rebuild head after a crash on my E-Flite B400.

If you get the arms level at mid-stick I think you will find that the positive and negitive degress on your main blades will be equal.

Tombo242 (This Forum) is an expert on setting these up and he told me this two days ago.

I crashed bad a year ago and just did a rebuild of the B400's head but never tried to fly it again. A week ago I tried to fly the B400 and she made one hell-of-a-noise. I cut the power and found that I had some missing teeth on the main drive gear. After getting real lucky in that my local hobby shop had two sets of gears in stock and after installing the gear I found that my washout control arms were not level and I have the same problem as you.

It's good to see a real question on the forum again.

Be sure to let us know how you make out. Most the time you never hear from the folks asking the question.

Good Luck

Jack
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rdsvark
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Location: SURREY UK

PostPosted: Sun May 19, 2013 2:07 am
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Thanks for that.
I have a TREX 450 Sport Plus and the washout control arms have to be at 90 degree rather than level to swashplate. Will check levels again

Rick
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tombo242
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Joined: 04 Nov 2008
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Location: Santo Estêvão, East Algarve, Portugal. Now 82, but still feels 22.

PostPosted: Sun May 19, 2013 5:26 am
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rdsvark wrote:
Thanks for that.
I have a TREX 450 Sport Plus and the washout control arms have to be at 90 degree rather than level to swashplate. Will check levels again

Rick


Hi Rick,

It's the 'seesaw' type arms on the washout block that must to be level at mid-stick. Here's a pic of what I mean. This is a Trex, but it is the same idea on all CCP helis.

All pivot points are in line.

Hope this helps.

Tom.
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Burgess
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Joined: 27 Mar 2012
Posts: 1077
Location: Wales

PostPosted: Sun May 19, 2013 5:42 am
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Hello rdsvark,

The short answer to your question, ‘...still learning, so does it make any difference anyway...' Most certainly Yes!

At zero degrees in Idle Up, blades, paddles, fly-bar, mixing arms, and swash-plate, must be perpendicular to the main axis.

To begin with set the Pitch curve percentages:
Idle Up 00, 25, 50, 75, 100
Normal 50, 62, 75, 87, 100
Set all three swashplate, mixing percentages to positive 50%.
Centre all trims,
Set sub-trims to 0%

Set flight mode to Idle Up and the Throttle Hold to off (disconnect all three motor leads):
With collective stick at the mid position
Servo arms at 90 degrees,
Swash-plate perpendicular to main shaft
Washout control arms at 90 degrees,
At this point the Mixing arms may or may-not be at 90 degrees nor the blades at their zero pitch position.

Take pitch reading at full positive, full negative, and mid-stick positions.

If the positive deflection is greater than the negative deflection, and if there is a positive deflection at mid-stick, shorten the D pitch link rods by one or two turns each, recheck maximum deflections and mid-stick, readjust the link-rods as required, when the positive and negative deflections are equal and zero at mid stick, then increase or decrease the swash-plate mixing Pitch Percentage to achieve the desired maximum pitch deflections.
This adjustment increases or decreases both positive and negative deflections equally.

Note:
The Idle Up pitch settings are needed for Auto rotation landing and provide a means to keep the heli steady on the ground when spooling up in windy conditions.
Once the basic setting-up of the head is complete, then, if you're flying out doors then reduce the first position percentage in Normal flight mode to provide some negative incidence at bottom stick position.
Also, reducing the swash-plate A & E mixing percentages down to 40% to 30% will soften the cyclic response.

Burgess
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rdsvark
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Joined: 16 Jul 2012
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PostPosted: Sun May 19, 2013 3:57 pm
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Thanks for detailed description.
Have managed to get same positive and negative pitch with swashplate and mixing arms level.

What I did was to lower the links on the swashplate to servo arms and re did pitch settings.
All equal now. Will try your method next time from scratch, good practice. Got to grips with mechanical and electrical set up of Heli. Need to learn to fly it properly now!

Rick
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rdsvark
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PostPosted: Sun May 19, 2013 4:01 pm
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Burgess, the D pitch link rods you mentioned, are they the ones linking swashplate to the control arms that affect blade pitch, or links between servos and swashplate?
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Burgess
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PostPosted: Sun May 19, 2013 6:48 pm
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Align designate the links as:

A...Blade holder to control mixing arm (Pitch adjustment corse) short links

B...Flybar control frame to washout mixing arm

D...Swash to control mixing arms (Pitch adjustment fine) long links


M...Port servo to Swash (pitch/aileron)

N...Starboard servo to swash (aileron/pitch)

O...Rear to swash (elevator)

Prior to the one-piece A and B links, they used to be adjustable.
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rdsvark
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PostPosted: Tue May 21, 2013 3:24 pm
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Thanks thought it was them. makes it easier when there is only one to adjust.

Rick
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