Choosing a motor equivilent to Power Pack C

[wedgetailaus]

Hi all,

I'm just getting into scratch building, and being from Australia, my foamboard is on the heavy side. I'm looking a building a few of the different FT designs and have ordered a power pack b from the FT store and am waiting on delivery. I'm thinking that given my planes will be a bit heavier, I want to get some more power for the larger aircraft (e.g. simple soarer, explorer). Could you please help me determine something suitable for the purpose from Hobbyking? I'm thinking something similar to what is in power pack C. I have very little grasp of electric motors and am basically choosing based on how many grams the motor is, the watts, and the kv. I don't know if they all use a generic spacing of mounting bolts, how important width and length is, etc.

This seems to be the motor included in pack c -
http://www.emaxmodel.com/brushless-motor/gt2215.html#product_tabs_description_tabbed
http://www.headsuphobby.com/Emax-GT221509-1180kv-Outrunner-Brushless-Motor_p_1354.html

Would something like this from Hobbyking matched with ESC be comparable?

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=18225
http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idProduct=35063

Thanks for you help.

Cheers

Wedge

 

[m00ndancer]

First, use this site to decide how much power you need: The Watts Per Pound rule.

80-120W / 454 grams or 18-26W/100grams should be enough.

The powerpack B motor will pull about 200W with a 10x4.3(slowfly) prop.
Should cope with a slightly heavier plane.

For comparisons I have a FT Spitfire with a Turnigy D2830-11 1000kv/30A Plush ESC running a 10x6 folding prop with a aluminum spinner. 911gr AUW(All Up Weight=everything incl LiPo) with a HK graphene 3000mAh 15C 3s LiPo. Flies like a dream, take off at 50-60% throttle and flies for about 15 mins.
Not unlimited vertical but enough for light acrobatics (loops, rolls, hammerheads and immelmans)

Sidenote: The plane has gained about 50gr in mods and repairs since I built it.

Haven't measured the watts on my setup, should be around 200W+ (theoretical output 21A*12.6V= 264W)
Using that data i get this result: 200w/911gr = 22W/100grams

The only caveat is that a heavier plane will fly, but at a higher speed to compensate the added weight.

 

[wedgetailaus]

Thanks fir the great reply, M00ndancer. Your post and included link are really helpful for me. I'm going to go with -

http://www.hobbyking.com/hobbyking/store/uh_viewItem.asp?idproduct=36580

http://www.hobbyking.com/hobbyking/...r_w_BEC_AU_Warehouse_.html?strSearch=plush 30

And I suppose an 8x4 or 9x4 prop for my FT Explorer. I'm expecting it to be heavy with my Australian FB and packing tape covering for strength and waterproofing.

We'll see how it turns out!