RE: PowerBox in Fei Bao hawk
The truth is that most of the planes out there with powerboxes don't need them. It would be a relatively simple excercise to measure the current draw of each of the servos, add them up and see if you are exceeding the capacity of a standard receiver. Another simple test is to start with a fully charged battery, recharge after one flight to see how much current is use during a flight. Hard data is always better than opinions.
Many guys in the jet community, including some of the self appointed experts, lack a basic understanding of electronics or simple mechanics. The easy thing to do is throw money at it, then not worry and there is always someone willing to sell you the latest gadgets whether you need them or not. It's part of the more is better or I've got to have the latest technology mentality. A lot of jets around today have 400 in. oz. servos and 5000+ mah batteries that nobody had a problem with flying 5 years ago on 100 in. oz. servos and 2000 mah bateries.
If you properly size your servos and set up the linkages to not bind and with appropriate mechanical advantage you will minimize your current loads. Certainly some applications need a powerbox, and some could benefit from one, but those tend to be the larger most complex ones.
In the case of your friend's plane he has way oversized servos on the elevators (over 800 in. oz.). If it were my plane I'd have 8411's, or at most 8611's on the elevators. Also he'd be better off with analog servos on the flaps to minimize current draw.
Joe