I starting a scratch built 2x50mm bird, what would the power consumption be?
What size lipo would you suggest?

Each of the Wemo 50mm fan and 6000 KV will pull about 350 watts so 700 total watts for the pair. I typically run a 3S 1800 25C for one of those setups but I fly full throttle the whole flight so eat up the power quickly. Probably a 3S 3000 would be fine. I also have a 4S setup that is about the same total watts (the 4800 KV motor) , I typically run a 4S 1320 in those jets so maybe a 4S 2200 would be OK if you had some throttle management.

Before i pull the trigger on these, your web site states 430watts on 4s with the 4800 is this typical?

the reason i'm asking is the bird is getting heavy, i miss quoted your web site in the below link.
http://www.rcgroups.com/forums/showt...1681958&page=4
And as the build draws closer to completion, i may have been strong on my weight calculations, im now hoping for 36oz AUW, providing my thoughts below.

the 4800 on 4s pulling 29amps at 430watts
I could shed some weight going with the 30amp esc rated for 40amp burst, also these are linear becs, and will also eliminate the need for a Ubec saving more weight.
Is my thinking correct?

Thanks again, oh and could i request red stickers with the purchase?

Originally Posted by D_FAST

Before i pull the trigger on these, your web site states 430watts on 4s with the 4800 is this typical?

That is pretty typical.

Originally Posted by D_FAST

I could shed some weight going with the 30amp esc rated for 40amp burst, also these are linear becs, and will also eliminate the need for a Ubec saving more weight.

To be honest the Pentium 30 on 4S do not like to be pushed hard. They can overheat easily and then they throttle back to half throttle to allow them to cool. Having a linear BEC means that the the ESC will be even hotter as it has to dissipate the 4S lipo voltage down to 5volts. I think you would be better off getting the 40 amp as they have a 3A switching BEC in them. So just disable one red wire on one ESC to disable the BEC then plug the servo leads into a Y harness and run your servos off the built in BEC and save the weight of the external BEC.

Originally Posted by D_FAST

Thanks again, oh and could i request red stickers with the purchase?

Just specify in the comments that you want red.

Received in perfect condition.
who would have guessed 2x50mm flying a 36oz ship at 1/2 throttle

The J 14 Project (2 min 37 sec)

That looks great D_FAST! I'm also in the early stages of planning a twin 50mm project. Do you (or Don) know the weight of one of the wicked units?

im sure the Don has it. ive forgtten

About 84 grams assembled.