Starting with closed props

[steve.r]

As the title says... I have been watching loads of YouTube videos and on a few occasions these pilots are putting their Spark on the floor with closed props and taking off directly like this. I always take care to open the props to the 180 degree position before I try and take off. Seems a bit crazy to do otherwise, and risking a stupid malfunction. Any of you guys do this too? any thoughts?

 

[DPJ]

The rotational pull of the props spinning up will open them easily. It’s probably not recommended by DJI, but I wouldn’t have thought it’s going to cause any issues.
Btw, I do the same as you, but I do see a lot of people not opening the props up first.

 

[steve.r]

I have a couple of the original props that are a bit stiff, so I always open.

 

[msinger]

I always open the props before firing up the motors, but I cannot imagine they wouldn't be able to open on their own without fail every time.

 

[Sparkbart]

I open the props just because I'm already down there powering it on. If it were truly an issue that could cause problems by not opening them up prior to starting it up, DJI would have made the props a non-folding piece and made you install them before flight and remove them after flight.

 

[suprPHREAK]

Leaving them closed won't cause harm, and they will open up.

That said, taking a moment to open them first gives you a chance to inspect the props for damage before your flight. I would recommend it as best practice.

 

[ulnar]

You can search for slow motion videos on YouTube where you see that the dron suffers stronger vibrations when you leave the props closed than when you open them. It's better to open manually the propellers.

 

[Rafa7]

You can search for slow motion videos on YouTube where you see that the dron suffers stronger vibrations when you leave the props closed than when you open them. It's better to open manually the propellers.

Yep, that makes a lot of sense. Thanks.

 

[Spark 317]

If the military does it with their big toys, it sure wouldn't hurt to do ours.

Safety first.

 

[GearHead83]

I always start with closed props. However I also always launch from my hand.

 

[suprPHREAK]

You can search for slow motion videos on YouTube where you see that the dron suffers stronger vibrations when you leave the props closed than when you open them. It's better to open manually the propellers.

It's why DJI products do that throttle up down up thing before takeoff: to get passed the vibe stage. Haven't tested, but I imagine if the big vibes don't stop, it won't fly.

 

[idbl_fanatic]

I never even thought about this, I have always started closed

 

[DesertWindAero]

Why not just take the extra initial load off the engines by opening them? It's not a big deal.

 

[Bob Radford]

It really doesn't matter at all, just do what you think is right

 

[Stevan]

For the extra 15 seconds it takes you to do it I don't see why you wouldn't open them?

 

[Bob Radford]

if you think about it, the torque of the motor, by the way, its not an engine, will run ahead of the hinged prop causing it to momentarily fold in until the centripetal force of rotation drives it outwards. So straightening them out really does nothing. It happens all by itself,

 

[Tomthumb1]

I agree, the startup torque will just shift the props until centrifugal force takes over and opens them. So straightening them out really does nothing.

 

[Rafa7]

if you think about it, the torque of the motor, by the way, its not an engine, will run ahead of the hinged prop causing it to momentarily fold in until the centripetal force of rotation drives it outwards. So straightening them out really does nothing. It happens all by itself,

I agree, the startup torque will just shift the props until centrifugal force takes over and opens them. So straightening them out really does nothing.

This makes sense too.
We are to the point that proof is needed, any slow motion videos of both of these cases?

 

[steve.r]

In my mind, it still causes unnecessary stresses on the props and rotational turning mechanisms

 

[smolly]

There is some proper overthinking going on here.
We are not starting an Airbus.
Based on scale, I really don't foresee this being an issue either way, otherwise we would not have folding props.