I built a Nobler from the Brodak kit
with Enya 40 and 4 oz metal tank
and it weighs 43 ounces all up
when I removed the engine and tank
it now weighs 26 ounces, never built
a plane this light before, so would
like to convert to electric, what is
the recommended spec please ?
I can get an Axi motor locally and
the battery not a problem , maybe
go to Shultz & co for ESC and timer

what Axi is most suitable and would
4 cells 2500 mah lipo be Ok ??

Thanks in advance

Vincent

Vince,
I use:
Scorpion 3020-16  (kV~800-880)--equivalent AXI is 2820-14 (kV=860rpm/volt)
Battery FMA 4s2100mAHr --so your 4s2500 should be fine
Castle Creation Phoenix 35A ESC--I am sure the Schultz will work fine
JMP-2 timer
Prop--APC 12-6 turning at 7950 rpm. If you want a smaller prop (like an 11-5.5) you will turn it at a higher rpm so you will want a kV on higher side of my range above (AXI listed should be fine)

My total up weight with battery is 44oz.

Hi Alan
Looks like Scorpion motors not available here,
and can only get the Axi AXI 2820/12 as the 2820/14 is not stocked locally
No of cells 10-14, - RPM/Volt 920 - Current Capacity 36A/60s - Dimensions 35.2 x 48.5mm - Shaft Di. 5mm - Weight 161g ( less than 6 ounces )
Can you tell me please, is that suitable ? or would the 2826/10 be OK?
Not in a hurry to order, I want to be able to oranise all the components up for July delivery
I am interested also in the charger that will charge 4 batteries at one time, wonder about
balancing though, see also some that will do 2 batteries at once
although I flew an electric Cardinal size plane last year this is a minefield !
again many thanks for the help

Vincent

According to Tower site, the PolyCharge4 will do up to 4S on each of the 4 outputs.  It will charge at a max 3A rate or slightly over 1C for the 2500 packs.

On the downside, it does not have a balancer, I feel that you really should have a balancer, and I am in the habit of using one EVERY charge.  The The Equinox balancer at $35 each x 4 would let you charge and balance through all four stations.  NOTE not everyone thinks you have to balanc EVERY charge.

Note Alan's precaution about having an adequate power supply.

After taking all this in I decided to hold-off on the PolyCharge4 in favor of multiple charger/balancer units, like the units coming out of Hobbycity.com.   

<snip>..

to Alan, one more query please:

I can get Hyperion batteries and motors from Robotbirds, no import duty

I would like to use a smaller prop, possibly down to 10x6 Zinger wood ?

would the Hyperion ZS 3020-08 @ 1135 Kv be suitable please ?

I will be using Hyperion 4 cell 2500mah 25C batteries
or I may opt for the A123 pack which is available
in 2300mah x 5 cells pack but that may need a
different motor/prop

Expect (hope) to have a flight with this late July

many thanks for all the help

Vincent

At first principles, it sounds like the Hyperion would work. Just check that the "3020" refer to a stator which is nominally 30mm in diameter and 20mm long (also the length of the magnets). Some manufacturer's use the designation to specify the outside dimensions of the motor can, and the inside "guts" can be quite a bit smaller. You can reference the Scorpion site to see what I mean by the dimensions. Another way to cross-check is that the motor should be about 5-6 oz (140-170g) in weight. After all, these motors are basically copper and iron, and for a give physical size and power handling, they will tend to weigh about the same.

I just looked at the Hyperion site and that 3020 motor looks fine.

I am not positive about the A123 batteries, but I think a 5s is nominally equivalent to a 4s lipo in voltage, so I think the rpms you want to get with a 10-6 prop  (~10k)  should be ok.

Hi John
thank you for your reply.
The A123 batteries are close to Nicads in use
I am waiting for dimensions and weight and charger
information, to decide if I will choose
4 or 5 cells as they are 3.3 Volts per cell ,
 4 might be marginal and 5 might be too
heavy...............needs care

will post results in due course


Vincent