Making a Deltawing RC

[Overdriven]

Using 1/10 buggy size tires could work out well. I'm not sure how exact of a replica he's going for, but a bellcrank setup like you described could be problematic. As you turn a bellcrank from center the drag link not only moves to the sides but also moves closer (forward and back) to the pivot point of the bellcrank the further you turn it. With the drag link attached directly to the knuckles this forward movement will also steer the knuckles, either amplifying or canceling out the desired steering movement. At the very least it will result in some weird steering angles and it could result in binding as well.