Prop Guards = Lots of Crashes?

[GWPhantom2]

So after a few successful flights I decided to equip my Phantom 2 with prop guards. I've only taken it up a couple times with the new DJI prop guards installed. Both flights I experience wobble of death crashes from about 40 feet above the ground. After installing my FPV setup, I decided to do a quick low altitude test flight over my back yard this morning.

This is what happened...
https://vimeo.com/89716864

Can anyone confirm or deny that prop guards are susceptible to wobble of death crashes? I'm getting really annoyed with shattering props on these out of control crashes. In less than a week i've shattered 4 sets of props.

Keep a close eye on the beetle at the end.

 

[OI Photography]

Speed of descent with a Phantom needs to be controlled anyway due to the physics involved which can result in a loss of lift while coming down...the prop guards can make this effect kick in sooner due to the bite they take out of your total lift produced.

So, yes, the prop guards can hasten the onset of what you experienced, though it can still be avoided even with them on.

 

[MikeySoft]

...
This is what happened...
https://vimeo.com/89716864
...

The poor bug in the grass ran for his life. :lol:

 

[GWPhantom2]

Speed of descent with a Phantom needs to be controlled anyway due to the physics involved which can result in a loss of lift while coming down...the prop guards can make this effect kick in sooner due to the bite they take out of your total lift produced.

So, yes, the prop guards can hasten the onset of what you experienced, though it can still be avoided even with them on.

Yeah I get the speed and angle of descent. Happened on a much higher flight. However I wasn't even descending on this flight and it just started to wobble and fell from the sky.

 

[OI Photography]

Understood, it just looked like you had stared to descend before it totally went nuts. Other than the slight effect they have on the propwash and thrust, the propguards shouldn't cause a lot of instability in normal flight. They can make the Phantom more sensitive to wind, but it would have to have been a huge gust to flip it over like that (and I'm sure that wasn't the case).

Let me ask you this, when you installed the prop guards did you put them on with the screws they came with or the same screws you removed from the holes so you could put them on? One possible cause of what you're seeing is the motors not being bolted on secure enough, to the point where they eventually wobble...just a guess though.

Have you tried flying again without the prop guards? Just be sure to put the stock screws back in when you do, not the longer ones that came with the guards.

 

[GWPhantom2]

Thanks for your input. Yes I just finished a test run without the prop guards and it seems to have more stability in all aspects of flight. I'm really timid when I land the Phantom now because most of my crashes have been during descent. I've also begun catching the bottom of the phantom when landing to avoid tipping while landing. I'm running Graupner E-Props and feel pretty confident in them.

After looking at the footage again I was slightly descending, you are right.

If someone could design a parachute system with a simple release button that would be amazing. Something with a simple kill switch that would kill props, deploy a parachute and allow your phantom to coast softly to the ground below. Anyone up for the design build? :?:

 

[OI Photography]

I'm running Graupner E-Props and feel pretty confident in them.

I've never used the E-Props, but I've heard mixed reviews of them on the Phantom...no idea if they might be the source, but I know others have sworn off them for the Phantom.

RE the parachute: there's a couple of places that have already rigged up a chute to larger multirotors, but none of them have added a motor killswitch to the mix (and I'm not sure how that would work)...but even with one it's still a lot to load on your drone for a very narrow range of situations when you could use it. Maybe it just needs the right design

 

[Big Ben]

I heard motor accelerations when it behaved strangely. If you are not using the original self locking props one of the prop nuts might have been loose. Try the prop guards with original props and see how that goes.

 

[ianwood]

There are two steps to fix your problem:

1. Put your stock props back on.
2. Educate yourself on vortex ring state.

 

[Rob98723]

What your saying (quite sensibly) is that when descending the props are causing eddies that effect the air flow over the prop blades. The quad can't rectify this loss of lift. Sounds sensible, but are you at max weight limits ?

 

[Bugsbunnyheli]

I have use prop guards since my first flight and have yet to have a problem.
Since I have not flown without guards I have nothing to compare them against.

But having them on has made me more confident in landing. They saved me in 2 tip overs while I landed so they paid for themselves already.

 

[CJ31]

Speed of descent with a Phantom needs to be controlled anyway due to the physics involved which can result in a loss of lift while coming down...the prop guards can make this effect kick in sooner due to the bite they take out of your total lift produced.

So, yes, the prop guards can hasten the onset of what you experienced, though it can still be avoided even with them on.

Yeah I get the speed and angle of descent. Happened on a much higher flight. However I wasn't even descending on this flight and it just started to wobble and fell from the sky.

Definitely looks to me like you were descending (and quite quickly) before the wobble started. You can see the black SUV across the street disappear behind the house and it happens pretty fast.

 

[Great Pumpkin]

Ditto having used DJI prop guards for over 25 P2V flights in 6 weeks - no problems.

 

[npvw]

Yes. I have experienced the same problem twice with my prop guards installed.
It just starts to wobble and then plunges from the air. There was still at least 2 bars left on the battery.
Luckily no damage to the camera.

I have never had any instability without prop guards. I have since not flown with them.

Regards
Nicolaas
South Africa

 

[bfenty]

I just got a set of prop guards and am also experiencing a lot of wobble in my flight. I've had a ton of flight time without them and almost crashed twice with them on-it feels like I'm flying drunk (I'm not lol). Will be taking them off and seeing if that makes a difference. I was excited to get them for added safety but now I don't trust them on my quad anymore.

 

[gruvpix]

I just got a set of prop guards and am also experiencing a lot of wobble in my flight. I've had a ton of flight time without them and almost crashed twice with them on-it feels like I'm flying drunk (I'm not lol). Will be taking them off and seeing if that makes a difference. I was excited to get them for added safety but now I don't trust them on my quad anymore.

Also had prop guards on at first and experienced VRS with a slow descent. I upgraded to 3.04 (not 3.06 yet) and removed the prop guards. Now I can apply max down throttle, down with yaw movement and many other previously risky inputs without being able to crash the thing. I would HIGHLY recommend removing the prop guards. Buy a couple new sets of props and change em out as needed.

 

[g1967]

Those of you that fly with prop guards on do you also have the sting between the guards or not?

 

[fastsmiles]

I have use prop guards since my first flight and have yet to have a problem.
Since I have not flown without guards I have nothing to compare them against.

But having them on has made me more confident in landing. They saved me in 2 tip overs while I landed so they paid for themselves already.

What brand of prop guards are you using?
I am wondering if there is a particular brand or design that is not causing problems.

 

[Robinj5981]

I bought prop guards! Three flights 3 crashes now they are in the bin!
I think DJI needs to come up with a lighter and stronger design.