On Sun, 27 Apr 2008 11:59:42 -0700 (PDT), dunkeldwest@[EMAIL PROTECTED]
wrote:
>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.
You're going to kill the packs like that. Once the speed control
starts pulsing, you've discharged too far. It's past time to land and
change packs.
6 to 7 mins is about the limit for a 450 with 2200 mah cells.
Hovering takes a LOT more power than forward flight so you'll probably
want to reduce that flight time to 5 or 6 minutes.
>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.
It's an operational error on your part. Regardless of how the heli is
set up, you need to do some tiral and error "homework" to find out how
long you can fly and then set a timer on your transmitter to beep when
it's time to land.
For LiPo packs, you don't want to discharge more than about 80% of the
pack's capacity. For example, if you're flying a 2000 mah pack, the
most you want to "take out" is 1600mah (1600mah = 80% of 2000 mah)
Taking more out risks damage to the pack and reduces the longevity of
the pack. If you really discharge the pack, it could swell, overheat
and burst into flames.
Starting with a freshly charged pack, fly for 4 minutes, then land and
let the pack cool. Now recharge it, taking note of how many MAH are
put back in. Divide that number by 4 and that'll give you an idea of
how many MAH/minute you're taking out. Let's say it's "burning"
250mah/min. 1600/250 = 6.4mins so set your DX7's timer to 6 mins and
when it starts beeping, land and change packs.
That should keep your packs healthy and long lived.
>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
Those numbers mean almost nothing without a pitch guage and swash mix
percentages. In normal mode on my 450s, I set up for about -3 to +12
on collective pitch, with 0 pitch at mid stick. IDLE 1 and 2 both get
-12 + 12. My NOR pitch curve when I was running a DX7 was 0, 42, 50,
75, 100. IDLE were all 0, 25, 50, 75, 100
>Throttle curve
>
>L=0
>1=20.5
>2=43.0
>3=69.5
>H=100
>
>Am I on the right track?
This was set up by the local "expert"? So at mid stick, he's got it
running at less than half throttle and probably 4 or 5 degrees of
pitch?? That's a nice way to overload both battery and motor..
The 450 likes a fast headspeed. I run my throttle curve in NOR at 0,
40, 80, 90, 100. IDL1 is 100, 95, 90, 95, 100 and IDL2 is 100
straight across.
>What do you suggest as a first step?
Find a new expert. :)
Head over to www.helifreak.com and register. Once you're there, visit
Finless Bob's HeliFreak Tech Room and look for the "450SE and General
Build Videos Here" thread. Download the CCPM1 and CCPM2 videos and
watch them repeatedly until you understand what's being shown. It
will be of immeasurable help to you when you crash and have to set the
head up again.
In the same forum is Jermo's DX7 video. Download that one too.
Those will get you started down the right path.
|
