Use of Manual Mode for fast descents

[dpdpkpcom]

I saw a recent post in another thread that made me consider assigning the failsafe S1 switch option to manual instead for enabling fast descents. We still retain the failsafe option indirectly by switching the transmitter off if my understanding is correct.

Just wondering what others' views are on this ? Obviously I understand the need to keep lateral airspeed up to avoid vortex ring state when descending (especially descending fast).

Shared experience welcome on this matter.

I have never been brave enough to try manual mode. My understanding is that there are no safeguards in place for preventing the bird from flipping over etc....

Reassurance or dissuasion welcomed !!!

Thanks

dp

 

[Mori55]

I think you'll crash your quad. How high are you going that you need to get down so fast ?
Other guys have talked about doing a csc and shutting it down and then restarting the motors .
If your new at this just learn to fly, leave your camera on so we can all watch the carnage!

 

[justin00]

If yoilu shut motors off wont it just drop down ? And not horizontally stable? But drop heaviest side first??
Either or... so starting motors again is an oprion and it will right its self once props have abit of power??

Would love to see a vid of this

 

[max]

I also saw that post and wondered other opinions. Descending in gps or atti painfully slow. I've never tried manual mode either. If you were completely out of control, could you flip back to GPS and have the bird recover itself very quickly? Given enough altitude that is..

 

[flyNfrank]

I hate how slow our quads descend! I have actually began talking with a few people in the aftermarket to come up with a nice solution. Btw, before I move off this subject, the actual reason for the current descent speed points to our vPlus. Soon after they were released to sell, a great deal of new owners were not slowing down soon enough that when their vPlus hit the ground it broke the gimbal. New owners of coarse blamed dji saying it wasn't their fault, ect. Not only was it an issue with breaking parts but they also changed the speed for fear of coming down on top of someones head. Prior to the speed descent being changed we enjoyed a better 9+mph average. I generally saw between 9-14mph. And of coarse now it is at 4.2-4.6mph.

As for shutting & restarting the quad while in flight, it can be done. And for anyone wanting to see it first hand on video just go to the thread titled something like Drop from 6,000ft. In the 1st or 2nd post there is a link which shows someone with a P2V gopro setup. The kid runs super low on battery and shuts it off and lets it drop maybe 1,000ft before turning it back on. So when the power to props shut down, the quad stayed what I call level for somtime. It then finally began to tumble, but soon after he powered back up, it leveled upright again and he returned to descending again, until the battery died around 500ft, I think. Btw again, when our quads are in gps mode they are like a cat that if you drop the cat it will land on 4 paws. I actually call my quad flyNcat. There is a video of a guy trying to throw his phantom at the ground upside down, and right after it comes out of his hand it is turning upright. Don't forget to check out the vid in the 6,000ft drop.

 

[Panamon Creel]

hmmm well the problem I see with a mid air CSC shut down is that you have to power the motors back up early enough to be able to recover. Now what if the Naza-M decides to not allow the motor power up due to some condition it doesn't like? -----> Splattttt!!!!. Manual mode drop is safer IMO, motors stay on and you can switch to GPS-Atti or Atti mode for it to stabilize if you can't do it in Manual.

 

[HunterSK]

My understanding is that the slow descent rate of 2 metres/second was implemented to avoid the occurrence of Vortex Ring State. I assume you all know what this is, but if you don't here is a link:

http://en.wikipedia.org/wiki/Vortex_ring_state

I prefer to run firmware 1.08 on all of my Phantom Vision+ (I purchased two), this does not have the descent rate limitation but I'm very conscious to avoid VRS and avoid rapid vertical descents.

 

[justin00]

It is very slow... but how high are you guys flying???... and if its high enough to worry... I assume no planes or anything ever fly by lol..
like you might own the land, but don't own the air space... Perhaps the laws are different where some of you are

 

[ZAPPATA007]

Very interesting topic indeed......what is the difference (speedwise) between manual mode and ATTI ?
Also; if one shots down the motors to get the bird down faster.....will it "flip" over and hence no possibility to recover control even if you put back gps?

 

[Dirty Bird]

With no wind in GPS mode the Phantom should fly @ ~35mph. In ATTI mode you can easily achieve 50+mph, but she will bleed altitude at max so you must be aware of your altitude and apply throttle to maintain.

If you were to shut down the motors completely and restart, "theoretically" the aircraft should regain control and stabilize once they are restarted, regardless of orientation. Provided, of course, you restart high enough to allow time for the aircraft to recover. If doing this with low battery, recovery would take longer due to reduced lift. Except in the most dire of circumstances, I would not really recommend this method.

 

[samd012]

I didn't read anything in the original post about shutting down motors, just entering manual mode to descend quicker. I have not flown manual on the pv2+ yet but I have on other quads. I would think if you enter manual mode and try to come straight down fast if the descent limit is not part of manual you could end up in a vrs. If you would just keep enough forward speed while you desced it theoretically should be fine. Has anyone tried that yet?
As for your situation if you want to try manual I would climb high and feel out manual mode before trying a fast descent, I have put my phantom in manual mode briefly and will tell you there is a drop in altitude immediately when you hit the switch and you must increase power to maintain altitude. Half stick is no longer hover point. Manual mode you just have to fly the quad 100% of the time. There biggest thing is if you let go of the sticks it will come down not just level out and wait for you to continue. Also the wind if present will push the quad, to hold position you will have to be in a state like forward flight with the sticks but will not be moving. If you tilt the quad it will stay tilted and accelerate fast. To counter you have to stop it yourself and then level it as opposed to just stopping it in att. Like I said, 100% of the time on the sticks or the quad will wander.
As for putting manual on the switch and taking away rth, yes the only way to engage it would be loss of signal whether by flying out of range or shutting off the radio. The way the system work is once you turn the radio back on you should regain control. But be careful, turn the radio back on in manual mode and it will drop like a rock unless you compensate on the throttle. I would put it at least into att before you do that

 

[thedjiguy]

I believe this video applies to this conversation and may help you guys out: https://www.youtube.com/watch?v=heIrawl ... 3GjL3x713g

 

[opassac]

one thought that crossed my mind... Wouldn't descending without power (after a CSC) make the self tightening props came off?

just curious.

 

[dpdpkpcom]

one thought that crossed my mind... Wouldn't descending without power (after a CSC) make the self tightening props came off?

just curious.

Very good question

I can't get my head around the answer. Thinking out loud here .......

The props stay on because the motors are exerting force in the tightening direction of the props. If there is no power, and the free-falling phantom remains level, the props will probably auto-rotate, causing the same tightening effect ?

If it inverted as it was free-falling, would the force be in the opposite direction potentially loosening the props ?

I can't get my head around it !!!!

Over to the experts ........

dp

 

[mmn]

one thought that crossed my mind... Wouldn't descending without power (after a CSC) make the self tightening props came off?

just curious.

If there's no brake or the brake is not set on the ESCs and the props can spin freely and if the props aren't on tight and if the UAV stays right side up, then they could spin backwards from the air pressure and could come off.

 

[BaldEagle]

one thought that crossed my mind... Wouldn't descending without power (after a CSC) make the self tightening props came off?

just curious.

If there's no brake or the brake is not set on the ESCs and the props can spin freely and if the props aren't on tight and if the UAV stays right side up, then they could spin backwards from the air pressure and could come off.

When I remove my props after having been on for a while, they get pretty tight and I might need the prop removing tool to help take them off. I also usually tighten my props a little bit when putting them on so there is some "grip". Don't you?

 

[opassac]

one thought that crossed my mind... Wouldn't descending without power (after a CSC) make the self tightening props came off?

just curious.

If there's no brake or the brake is not set on the ESCs and the props can spin freely and if the props aren't on tight and if the UAV stays right side up, then they could spin backwards from the air pressure and could come off.

When I remove my props after having been on for a while, they get pretty tight and I might need the prop removing tool to help take them off. I also usually tighten my props a little bit when putting them on so there is some "grip". Don't you?

Well, i never needed to use the removing tool, i always remove the props by hand (and i usually don't need to apply to much pressure), thus my question. If what tightens the props is just the rotation of the motors than, in theory, it seems to me that while descending the flow of the air would make the props spin on the other way allowing them to unscrew.

Not that this concerns me, never crossed my mind to do mid-air CSC's ... Except once, when a very very very low flying ultralight came really close, ouch