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Mike @ zen  
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 More options Apr 27, 6:58 pm
Newsgroups: rec.models.rc.helicopter
From: "Mike @ zen" <m...@nochance.com>
Date: Sun, 27 Apr 2008 23:58:07 +0100
Local: Sun, Apr 27 2008 6:58 pm
Subject: Re: Trex 450XL Pitch curve help

<dunkeldw...@gmail.com> wrote in message

news:aaa829d5-a419-47ef-8846-257e1b43b1fd@t63g2000hsf.googlegroups.com...

>I have joined the wonderful world of RC.
> After much deliberation I chose to go the heli route as I have a big
> garden
> and a park cross the road where I can practice.

> I bought a TREX 450XL CCPM kit complete with Align 450L motor and
> BL25T ESC.
> The radio is a Spektrum DX7.
> Batteries are flight power EVO Lite V2 2500mA.
> Gyro is the Futaba GY401.
> Charger is the Swallow Advanced and I have the flight power V Balance.
> I built up the kit and had it set up by one of the experts from the
> shop.
> I have training gear attached.
> Pinion was a 15T but I replaced it with a 13T.
> I have been through about 10 battery's so far and I am managing to
> hover at
> about waist height for a few minutes at a time.

> The problem I am finding is I am not getting good battery life.
> After 6 or 7 minutes the Trex starts pulsing which I am told is the
> sign
> that the battery is going flat.
> If I let the Trex rest for a few minutes (I assume the battery is
> recovering
> during this period), I can then take off and hover for a few more
> minutes.
> After the batteries cool down, the 2 of the 4 leds on the V Balance
> fuel
> gauge light up for each of the 3 cells in the pack.
> It could be my beginner way of flying, it could be not enough pitch ,
> new
> batteries, training gear weight,
> not enough pinion main gear slack etc. etc.

> What I would like to do first is change the pitch curve.
> It's in the normal position now with values of

> L=20.5 (is this too much negative pitch and should I change it to say
> 50%?)
> 1=55.5
> 2=77.0
> 3=92.5
> H=100

> Throttle curve

> L=0
> 1=20.5
> 2=43.0
> 3=69.5
> H=100

> Am I on the right track?

> What do you suggest as a first step?

When the Trex starts pulsing STOP flying and charge the battries or you will
fook them up.
For longer flight times use a 11T Pinion, it will do you for just hovering.
Next get a pitch gauge
Then........

pitch ....

Norm.
40 45 50 75 100

Idle 1...
0 25 50 75 100

Idle 2...
0 25 50 75 100

Throttle  you will have to play around with depending on what pinion you are
using

My t-rex 450 is  set up like this on  13T Pinion

Pitch

norm
40 45 50 75 100

idle up 1
0 25 50 75 100

idle up 2
0 25 50 75 100

Throttle

norm
0  50 70 70 80

Idle 1
90 85 80 85 90

Idle 2
100 95 90 95 100

I use the same Pitch curves on my T-rex 600e  and two t-rex 600n's

Have a look at a video called .....Pitch and throttle curves 101

http://www.helifreak.com/showthread.php?t=11373


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