C-ARF Extra 330L electric - RC Groups
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Sep 07, 2009, 06:03 PM
Pontus Claesson's Avatar
Build Log

C-ARF Extra 330L electric

This blog will be used to document the build and testflying of my Composite ARF EXTRA 300L.
A thread will be made in parallel for comments from you all and for me to ask questions when I run into problems to decide or find the best
Last edited by Pontus Claesson; Sep 07, 2009 at 07:24 PM.
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Sep 07, 2009, 07:23 PM
Pontus Claesson's Avatar

Open the box

All the composite parts.

Nothing else have arrived yet.
Motor will be Plettenberg Predator 25-8.
ESC Schulse XL 40.160
Battery 11s7150mAh EON-X30.
Spektrum AR9000
Hitec HS-79xx servos (type not decided yet)
Last edited by Pontus Claesson; Sep 07, 2009 at 08:41 PM.
Sep 07, 2009, 08:07 PM
Pontus Claesson's Avatar

Planning the CG

The weights of the parts out of the box:
PART__________________MASS(gram)____CG in relation to tube center
Body w/ c-frame_______1340________-300
Elev w tube____________400_______-1120
Wing tube______________335___________0
Gear legs______________345_________115
Motor dome_____________375_________300
Canopy glass___________200________-230
HW kit_________________200________-100
Wood kit_______________240___________0

A total of 5425 gr.-- A little more than expected but I have ordered carbon wing tube and carbon wheel pants from GraphTech, maybe save me 100 gr.
The HW kit and wood kit contain more than I will use too, includingalso some scrap.

The motor dome is one massive b-stard, I will throw it away and build
a hypostatic carbon framework. Target is to get rid of 50% of the weight.
Last, the gear legs is far to rigid for my taste. Will make new. Slightly
higer and with more flex. Target is 200 gr.

CG of the kit right now is -166 mm (behind tube center, I think center of tube
is a proper CG location but have not checked yet)
Adding 1500 gr motor-prop-spinner in the front gives me -26 mm.
I'm not worried at the moment, 2.5 kg battery to adjust with should do the
Last edited by Pontus Claesson; Sep 09, 2009 at 08:23 AM. Reason: added the cowl
Sep 08, 2009, 01:24 PM
8000 Watt Club
Geoff Dryer's Avatar
Have you tested how much thrust the Predator 25-8 will produce on 11 and 12 cells. I am planning on building a Hangar-9 Extra 260 (35%) for IMAC. I am aiming for at least 50 lbs of thrust on 12S. I an also trying to limit the batteries to 4 6S-5000s (12S2P) I am hoping that 10000 Mah will be enough for IMAC Sportsman.
Last edited by Geoff Dryer; Sep 08, 2009 at 02:43 PM.
Sep 08, 2009, 03:07 PM
Pontus Claesson's Avatar

Estimated data power system

By interpolating and extrapolating a number of prop data from Plettenberg
I predict this for a RASA 25x12 folding on P25:


Voltage: 41,8 V @ 20C (3,8 V/cell)
Revs: 6500 rpm
Thrust: 185 N
Current: 140 A
Input power: 5852 W.

In level flight I hope to gain a speed up to maybe 6900 rpm.
Gives a pitch speed of about 124 km/h.

I'm looking for both speed and thrust.
More thrust by choosing 26" or 28" prop doesen't makes sense
as I estimate all up weight 9.4 - 9.7 kg.

The motor is good for more but choosing the 250 gr lighter Terminator 30-8
had probably only caused me CG trouble. Now I have a motor that might fit also a 100" aerobat.
Sep 10, 2009, 03:32 PM
Pontus Claesson's Avatar

Stuff coming in soon..

Servos have arrived.

2 x HS7955TG for aileron
2 x HS7975HB for elevator (those are up-rated to 10.2 kgcm@6V, when did that happen?)
1 x HS7955TG for rudder

Predator 25 is shipped an will arrive Monday.
But I'm away from home until Wednesday

Still waiting for LiPo's (backorder)

Stay tuned!
Sep 10, 2009, 07:26 PM
8000 Watt Club
Geoff Dryer's Avatar
It sounds like the 25-8 won't be enough for my application (35% Hangar 9 Extra) as 50lbs of thrust is roughly 225 Newtons. I look forward to seeing the progress on your project.
Sep 15, 2009, 06:46 PM
8000 Watt Club
Geoff Dryer's Avatar
Originally Posted by Pontus Claesson
Geoff, just took a look on H9 35% Extra.

When it comes to the large Plettenberg motors my conclusion is this:

Terminator: 50-60 cc
Predator 25: 70-85 cc
Predator 30: 100-110 cc
Predator 37: 150-170 cc

The 'cc'-range for each motor has to do with how many cells and what capacity and C-rate you use.

If you find reports of your model with satifying performance using for example the DA-85 I think you can go for the P25 but IMO the P30 is the proper choice for
IMAC Sportsman (and up) for such a model.
Thanks Pontus. I agree with you statement. My plan is to run 12S2P using 25C batteries. My second choice for motor manufacturer would be a Hacker A150 but it is not a great option on 12S and it is heavier. The Hacker is less expensive though.
Sep 17, 2009, 08:50 AM
Pontus Claesson's Avatar

Predator has landed!

A first cell phone shot, more will come!


motor: 1294 gr
prop: 68 gr
spinner: 118 gr

diameter of mounted prop becomes 650 mm (25.6")
but it is named 25"x12". I guess effective pitch will also be a little
more then.
Last edited by Pontus Claesson; Sep 17, 2009 at 09:09 AM.
Sep 17, 2009, 08:58 AM
Pontus Claesson's Avatar

Trial fit of the EXTRA

Everything fits so far, on my way to pick up a carbon wing tube and wheel pants now. (neither of supplied as standard...)

The yellow machine down right in img is the genset for charging in field, more about this later.
Sep 20, 2009, 07:02 PM
Pontus Claesson's Avatar

Construction started!

To start with, carbon pants and wing tube received.
Pants were 68 gr, saving of 27 gr not much but the look cool too
Carbon tube weight 200 gr, 135 gr saving!

Started today with the cowl, I will let the cowl carry the motor and use
no dome at all!
First I fit a former in the rear of the cowl, then I make some reinforcements rear to front and put a plate in the front and finally I mount the motor on short stand offs.
So far only the former in place, solid 3 mm ply but it will be lightened of course.

Had to glue it with laminating epoxy+micro ballons+ground carbon fiber as my 30 min epoxy got very thick, don't know if it works any longer.
Sep 21, 2009, 05:34 PM
Pontus Claesson's Avatar

Power charger!

Received the AC-charger today.
Rated 18 A up to 15 LiPo. (1200 W)
A pure industrial device, to be programmed once for 1 type of battery.
But I purchased the programmer and software in case I want to change.
Weight is 3,6 kg.
Sep 21, 2009, 06:09 PM
Pontus Claesson's Avatar

LiPo invasion

Another 7 kg box hit the bin...

Contained a few LiPo's...and a nice ESC .

The Schulze ESC xl-40.160 offer a lot of features:
* Built in single cell voltage monitoring and logging.
* Dual temperature sensor inputs (motor + battery) both logged
* Hall sensor input for prop positioning and/or logging of speed of other device(prop can be braked in horizontal position)
* Current log
* Total voltage log
* Throttle position log
* ESC temperature log
* Motor speed log

All read over USB or RS-232
Sep 21, 2009, 07:09 PM
Gilbert, AZ
chalmrast's Avatar
You have some very interesting electronics here... especially that charger. I assume it charges in series and not each individual cell?
Sep 22, 2009, 05:25 AM
Pontus Claesson's Avatar
Originally Posted by chalmrast
You have some very interesting electronics here... especially that charger. I assume it charges in series and not each individual cell?
Yes, thats right. No balancing but a lot of other parameters possible to configure.

The charge cycle can be divided in up to 5 phases.

For each phase, max voltage, max+min current and time limit can be set.
Conditions to go to next phase can be current < I(min), Ub>Umax, time out, capacity limit etc.
For each phase, the LED's can be controlled.
Global parameters can be minimum start voltage, voltage drop compensation (long cables) and temperature compensation.

Data about the last 32 charge cycles are automatically stored in the charger and can be read over the USB interface.

Balancing has to be done with auxillary device, I use the Schulze LiPoProfiBal-14 for this. But I see no need to balance all the time, that can be done back home.

This charger should be used if you want to FLY a LOT and want to reduce the number of
devices to connect and carry to the field. But of course, 230 VAC is needed, I bring my 1 kW generator if the field doesn't offer a power grid.

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