enrique1123

I have a 2 projects going and I hit a brick wall, How manny watts of power to use on a given weight, I just finished a HOB Spacewalker .10 kit and I want to install an AXI but I don't know which one, Weight without motor or battery is 19 oz., I trimmed it a little and it is a 4 channel plane with separate servos for the ailerons. I am looking at the 221234 running 3 cell Lipo, but the figures in the past from Hobby Lobby don't really make sense so I need some help, I usually like to set up a plane with the same thrust as the AUW but in these figures I got stuck. so any input would be greatly appreciated. I have now a 281412 that I know would be too much, I had installed it on the Global AT-6 but it was too much for it and I know it would definitely be too much for the Spacewalker and don't want to spend the money again and find out the motor is not going to work out, since I have to find a plane for the 281412 now. thanks

Greg Covey

Hi Albert,

The [link=http://www.houseofbalsa.com/e/env/0001K32BKElk64AbpY3G9g2/store/store-kits.html?link=/store/store-type-tem.html&item=products:k-22]HOB Spacewalker .10[/link] has a 47" wingspan and is listed as 28oz in weight although it is unlikely with fuel.

The Spacewalker is an aerobatic plane so you'll want it to perform well. This means that you want at least 100 watts/lb of electric power. More than likely, this plane will be over 32oz with a battery pack so let's call it roughly 2lbs. Therefor, we want a minimum electric power system of 200 watts.

The 2814/12 that you already have can produce 200 watts with a 10x7 prop on 8-cells at 30amps. This is not taxing the motor and leaves you plenty of room to change the prop size by + or - 1" and add or subtract a few cells.

Here is the spec sheet from [link=http://www.modelmotors.cz/index.php?id=en&nc=produkty_vypis&url_ps=axi_2814_12&id_odkazy=m_ac]Model Motors[/link] in the Czech Republic. Hobby Lobby also host the data [link=http://www.hobby-lobby.com/brushless_axi.htm]here[/link] but only displays power to the prop, which, although a more accurate indicator, can sometimes lead to overpowering a plane.

enrique1123

Many thanks, that'll save me the expense of a new motor. Being semi retired don't have much else than time to play with my planes thanks again. I will be getting rid of my Multiplex Cargo and see How this Spacewalker turns out and then I'll finish the Pigi that Everyone is talking about.