so i binned my 5inch pretty hard into a concrete wall last weekend, totally my fault, was pushing it too hard in a tight gap and misjudged the entry angle. anyway motor 3 is completely toast, shaft bent, one of the bell screws stripped when i tried to get it off, the whole thing is just done. but also the arm on that same corner has a crack running about halfway through it, not all the way but its definitely compromised.

my question is basically do i bother replacing just the motor and fly it with the cracked arm or do i order a new frame. its a cheaper frame, like a geprc or similar budget build, so its not a huge deal to replace but i also have like 4 spare motors from a previous order sitting around so part of me just wants to slap one on and see what happens. the crack isnt at the joint where it meets the center plate, its like midway down the arm.

running 2306 2450kv motors on 4s if that matters. any experience with flying on cracked arms? i feel like it'll just snap on the next hard landing and i'll be dealing with this again anyway

dont fly on a cracked arm man, just dont. i did this exact same thing, told myself it was fine, flew two packs and on the third one it snapped mid-throttle punch and the props clipped together and i lost the quad into a lake. cracked arms fail unpredictably, especially carbon, it doesnt bend it just goes all at once. if the frame is cheap just get a replacement arm or a whole new frame. most of the budget chinese frames you can get spare arms for like 5-8 bucks shipped.

while youre at it check the motor mounts on the other arms too, concrete impacts usually stress everything even if you cant see it

yeah i had a cracked arm on my first build and honestly flew it for way longer than i should have. it held up but looking back that was just luck. carbon fiber cracks propagate really fast once theyre started especially under vibration. probably not worth saving a few bucks on a budget frame tbh. also 2306 on a cracked arm is going to be putting a decent amount of torque stress right at that weak point every time you throttle up