Im flying an Excelleron 90, not a 3D plane but Im doing knife edge loops and they're pretty good except coming down, it seems to take forever to recover to horizontal knife edge. Im cutting the throttle, should I give it some throttle to help the Rudder, get more altitude to recover???

yes, you need to add some throttle when you're about halfway on the down line, otherwise you might not achieve enough airspeed to maintain KE flight. Start w/ 1/3 throttle, but in most aerobatic planes more than 1/2 throttle should not be required. Make sure you're using a servo that's up to the task, 'cause this maneuver really puts a strain on the rudder servo.

Also start the KE loop 2 mistakes high to give yourself plenty of room to bail if things get hairy. Last pointer: you can cheat a little by rolling 5 degrees off KE (towards canopy in a low wing plane) to get a little extra lift.

Yup use your throttle on the down side. Coming over the top I am at idle. about midway I start to advance the throttle getting to 3/4 or more towards the bottom to make the plane come around smoothly.

Thanks Guy's I'll give it a try.

I am about to try this with a EF Edge, should i cut the throttle at the top to attempt to stall it to tighten the loop?

Starting at the bottom I go left rudder and start the loop. Adding as much rudder as it takes to make it look round. Towards the top I am about 3/4 throttle give or take.

As I start over the top I reduce throttle somewhere around a 1/4 and start opposite rudder to make the top of the loop nice and round.

Then I ease off the throttle even more starting to apply left rudder again, beginning my backside of the loop. Increasing throttle as the plane nears the bottom to make it come around nice and smooth.

Practice a few times, it will come together very quickly. [8D]