F450 quad frame?

[hershey]

I'm flying the F 450 quad. Everything is going well, way beyond my expectations and experience.
In the 6 weeks that I've been flying the quad I've lost two arms due to their breaking on landings. First was a fairly hard landing in 4" tall grass. It landed and immediately flipped over an landed on its props. Didn't break a prop. One arm broke near the motor.
The next one was more of a horizontal slam into a wooden fence about a foot off the ground. Again, not all that hard, didn't break a prop again. But the arm broke in much the same place....both were the white arms.
I've watched videos of someone trying to break an arm by throwing it hard onto a concrete floor over and over again. Way harder than any landings (controlled crashes?) that I've had.
Anyone else have a similar experience with the breaking of the arms in situations that really shouldn't cause that?

 

[wizzy87]

I'm flying the F 450 quad. Everything is going well, way beyond my expectations and experience.
In the 6 weeks that I've been flying the quad I've lost two arms due to their breaking on landings. First was a fairly hard landing in 4" tall grass. It landed and immediately flipped over an landed on its props. Didn't break a prop. One arm broke near the motor.
The next one was more of a horizontal slam into a wooden fence about a foot off the ground. Again, not all that hard, didn't break a prop again. But the arm broke in much the same place....both were the white arms.
I've watched videos of someone trying to break an arm by throwing it hard onto a concrete floor over and over again. Way harder than any landings (controlled crashes?) that I've had.
Anyone else have a similar experience with the breaking of the arms in situations that really shouldn't cause that?

Hersey

i have had the same issue but my quad twitched and hit the deck! broke a white arm each time. I think they are supposed to, mine broke at the same point, so could be a stress point. Like an airbag in a car!?

 

[LeeT]

I've busted three arms. One when a prop came off and the F450 dropped 15 feet and landed on one leg, and the other two when it fell 100 feet when a wire broke on the motor. If your breaking arms your landing to hard. My guess is that your piloting skills need improving.

 

[OneStopRC]

My guess is that your piloting skills need improving.

ouch..... Kinda harsh.

 

[OneStopRC]

I'm flying the F 450 quad. Everything is going well, way beyond my expectations and experience.
In the 6 weeks that I've been flying the quad I've lost two arms due to their breaking on landings. First was a fairly hard landing in 4" tall grass. It landed and immediately flipped over an landed on its props. Didn't break a prop. One arm broke near the motor.
The next one was more of a horizontal slam into a wooden fence about a foot off the ground. Again, not all that hard, didn't break a prop again. But the arm broke in much the same place....both were the white arms.
I've watched videos of someone trying to break an arm by throwing it hard onto a concrete floor over and over again. Way harder than any landings (controlled crashes?) that I've had.
Anyone else have a similar experience with the breaking of the arms in situations that really shouldn't cause that?

When you install your motors, make sure you're not over tightening the screws. I am wondering if your putting stress cracks in the motor mounts? From what you're saying, the breaks are where the motors are mounted right?

 

[tstrike]

I think you'd strip the screw heads before you could crack an 1/8 inch piece of plastic. I'm guessing he broke his arms right at the point before the motor mounts which would be the place with the most stress on a hard landing. I know I've done the same kind of bounce flip on mine but didn't break an arm. I read a thread somewhere on another forum about white arms being more prone to cracking but nothing scientific to back up the claim.

 

[hershey]

Thanks to all for their feedback.
First I'm sure my piloting skills could/should be better or we wouldn't be having this discussion. I suppose I'm the only one who has every had a hard landing with their quad so I'll try to do better.
My breaks are near the motor, about an inch or so from the motor and the fracture runs parallel to the arm for a distance of about 3". Not a straight across snap or break. Both arms are the white arms. Neither time did I lose a prop.
I've flown RC planes for over 7 years and I know what a hard landing is and I know what a crash is. Neither breaks were a result of a crash of the intensity that would break the arm.....not when I watch a video of a guy trying to break it on a concrete floor.
First break was a result of a hard landing on some grass and it just flipped over on its props. Broke the arm but not the props.
Second break was when I nudged (hit) a wooden fence and it dropped about 3' to a gravel area. Again, broke the arm but not the props.
I'm not trying to make excuses, neither breaks were a result of perfect landings, but neither should have broken the arms, they look very sturdy.

 

[LeeT]

Mine all broke at the same place, at the end of the arm, right before the motor mount / leg, almost a clean snap. These types of breaks are relatively common, and have been documented in several threads. The fracture your getting sounds like the arm is twisting which would cause the fracture your describing. Almost sounds like it could be a mfg defect, otherwise it would take a helluva lot of torque to cause that break. Do you have after market legs bolted to the short legs on the arms? That's the only thing I can think of that would amplify the torque to cause it to fracture.

 

[hershey]

I do use some leg extensions from time to time but only when using my camera. BTW: My legs are made from 1/2" PVC pipe. I just dremeled (sp) a slot into the leg that allows it to slip onto the straight edge of the F450 foot. Tight fit and it stays in place with no additional bolts or screws. They have served me very well with camera work. They just snap on and off. I painted two red to help with direction. None of my frame breaks were with the extensions in place. I'll try to get a picture of them tomorrow and post them. Very easy to make, cheap and works well.

 

[OneStopRC]

I have seen the demonstration too, with the throwing around and launching at the concrete floor with the legs. Makes you think they are invincible to a point, but as LeeT said, probably with the torque of the motor and the hitting could have done the trick.

I as of yet have not broken any arms, damaged any parts apart from a brand new pair of Gemfans.... Long story. Your also not the only one to crash/wreck your bird, I will laugh at anyone on here that tells me different..... lol.. So your not alone, just most of us choose not to brag about our mishaps.