Prop lost in flight

[teslahed]

I've just been out flying - it was a bit windy but otherwise the weather is good.

I lost a prop in flight. I was about 6 meters up and moving at about 15mph when the quadcopter suddenly lurched to the side. I wasn't totally sure what had happened in the few split seconds before i hit the ground but i did guess on the way down.

Interestingly after the quadcopter lurched to the right i throttled up and was able to regain control - i managed about a 50% controlled decent and landed right side up with no damage.

I wouldn't have thought that possible if i hadn't just done it. Shame i didn't get it on video.

I suspect if my props had been much bigger than 8 inches i would have shaken the quadcopter to pieces trying to use the motors and wouldn't have come away quite so undamaged.

[MadMax]

Well done like you say shame you didnt have it on video, when I lost a prop the copter just flipped over and hit the deck it wasnt very high though and just bust a prop it also landed upside down 

[Gaza07]

Glad to hear you got it down safely I stopped using collet type prop adapters because they seem to pop off to easy, I always use the type that clamp to the motor shaft with a grub screw and fit them with a little thread locker 

[teslahed]

I always use the type that clamp to the motor shaft with a grub screw and fit them with a little thread locker 

I think I've asked you this before but can you give me a link? I do like the look of your prop adapters and i have terrible problems with the rctimer ones - roughly 30% of them are bent on arrival.

I've never had one pop off - today the actual prop snapped at the hub. I have had an o-ring break before though - i quickly learned not to bother with prop savers. 

[Gaza07]

These are the ones I use http://www.giantshark.co.uk/prop-adapter-317mm-shaft-grub-screw-type-p-404888.html they seem to be out of stock again 
I ordered about 16 of them a while back as they had plenty they are cheap so buy some extra when they have them as the odd one might not be quite good enough, the prop adapters on my purple motors are the bolt on type and you can get them from rctimer for the 2830 range of motors 

[Gav]

I had a prop adaptor slide off the motor (see vid below).  I graunch on the adaptors now and check before mosts flights.

http://youtu.be/kQ8z60q4zEI

[Gaza07]

I hope you don't mind Gav I edited your post to show the video on the forum, all you need to do to show the video's is click the share button under the video in you tube and paste that link directly in to your post, thanks for sharing your video 

[teslahed]

Rereading my original post it seems i left out an important detail.

I only lost half the prop - one side of the blade snapped off at the hub with the other half remaining attached so i effectively ended up with a very badly balanced single bladed propeller.

If I'd lost both halves of the propeller i doubt I'd have managed the semi-controlled decent that i did.

Single bladed propellers do exist though - deliberately made ones have a counter weight so they don't produce vibrations like mine did;

http://en.wikipedia.org/wiki/Single-blade_propeller

[MadMax]

I did think you meant the whole prop with the adapter, because that does seem to be thee most common one, the vibes from the broken prop must have been very bad your lucky to have any control, I bet the sensor's weren't to happy 

[MadMax]

Nice video Gav shame about the prop coming off but you could send it in to you been framed and you might get £250 

[Gaza07]

i thought you meant the whole prop to 

Rereading my original post it seems i left out an important detail.

I only lost half the prop - one side of the blade snapped off at the hub with the other half remaining attached so i effectively ended up with a very badly balanced single bladed propeller.

If I'd lost both halves of the propeller i doubt I'd have managed the semi-controlled decent that i did.

Single bladed propellers do exist though - deliberately made ones have a counter weight so they don't produce vibrations like mine did;

http://en.wikipedia.org/wiki/Single-blade_propeller

[Gav]

tut come on you have to crash in style .. at least the whole prop adaptor assy came off on my attempt lol

[teslahed]

i thought you meant the whole prop to 

Yeah sorry about that. Usually I'm on the ball with descriptive detail too:cool:

The sensors really weren't happy but i used extra power and near full stick deflection and just about managed enough control to level out and slow my decent. Definitely worth a go if you find yourself in a similar situation but i suspect it wouldn't work so well with bigger heavier propellers and definitely wouldn't work on a quadcopter if you lost the whole prop.

[teslahed]

I've just worked out why i have such problems with my prop adapters.

With the simple screw to fit ones if you over tighten them you can very easily start to twist the metal itself. I discovered this just now when a particularly weak one just twisted right off and snapped - i looked back at some of the ones i had been having problems with before and i can see that i must have bent them when i was trying to get them tight enough to stop the prop from slipping. It seems like the point where they are tight enough is quite close to the point where you've overtightened and bent them, which is a bit of a pain.

I'll have to be more careful until some better ones come back in to stock somewhere.

[MadMax]

Aluminium isn't the best material for bolting things together as it has no tensile strength and shears easily, but it is very light 

[Gaza07]

I would agree except i think its more of a made cheap in china thing as you can get Aircraft Aluminium and I would imagine that would be much better quality but at a much higher price 

[BYOD]

I recall my first build, I totally over did it on the prop adaptors, caused one to rip the threads clean off the shaft! The "nip it" and "check it" before each flight now has severed me well for the past year and a half, no lost props, no broken props, so I would just work this in to your pre-flight checks, takes all of 30 seconds to check they are tight!

Regards

Martin.