Climb and descend from 400ft / 122m

Photo · Jun 9, 2018

Hi, does it drain the battery more or less to climb in a normal speed than to descend and land? Not taking the wind impact into consideration. I ask because I wanna be sure to have enough juice left for a safe landing from 400ft.

Eagle's Eye Video · Jun 9, 2018

All other things being equal it should take less energy to descend... not having to overcome gravity and such. All children learn this at an early age, watching their Father try to get up out of his chair in front of the television...

FlushVision · Jun 9, 2018

You have to factor in the time it takes to descend and land. The TH and most other uavs take far longer to descend from any given height than it does to get up to that height in the first place. So, as Eagle's Eye Video has said, yes, it will use less energy going down than up since it is traveling with gravity rather than against it, but since it will take longer to descend it will use energy for that.

PatR · Jun 9, 2018

A simple solution to all the guesswork; initiate a landing well before the battery is depleted.

Trying to obtain the last possible second of flight time from a battery might work a few times but it will most certainly end in disaster one time, and the odds are against you.

Photo · Jun 10, 2018

PatR said:
A simple solution to all the guesswork; initiate a landing well before the battery is depleted.

Trying to obtain the last possible second of flight time from a battery might work a few times but it will most certainly end in disaster one time, and the odds are against you.

Sure Patr, I always plan to land with enought "juice" I was just curious if there is alot differens between climbing and descending as the H has to struggle hard not to fall from the sky.

AH-1G · Jun 10, 2018

Basic physics!

PatR · Jun 10, 2018

AH-1G said:
Basic physics!

Perfect[emoji4]

rdonson · Jun 10, 2018

How Do Drones Fly? Physics, of Course!

Modeling the Thrust From a Quadcopter

NorWiscPilot · Jun 10, 2018

A couple points:

1) Nothing beats hands on experience; fresh battery - take off/ hover at say 10 feet/observe voltage - climb to desired altitude - observe voltage - descend - check voltage.

2) as has been recommended by others many times over the recent months - unless already over the desired landing area AND terrain permits... include a horizontal element during descent. Work on including your own “glide slope” to your landings. It not only looks cool, it maximizes what remaining battery one has left. Very important technique to use when levels are approaching or already at critical.

Jeff

rdonson · Jun 10, 2018

Excellent suggestion, Jeff

Eagle's Eye Video · Jun 10, 2018

Any geometry teacher that is not using a nano quad to demonstrate the hypotenuse, is really missing out on an excellent teaching opportunity

Ty Pilot · Jun 10, 2018

Photo said:
Hi, does it drain the battery more or less to climb in a normal speed than to descend and land? Not taking the wind impact into consideration. I ask because I wanna be sure to have enough juice left for a safe landing from 400ft.

Maximum climb speed is 5ms and max decent is 3ms so with a total of 122 meters that's a climb time of about 25 seconds and a decent time of around 40 seconds. Personally I think that climb speed is a little optimistic or maybe its just because when I climb I don't use full throttle but the descend speed is about right on.

As an exercise, time a flight with a fully charged battery in which you put the 400 foot climb followed directly by the decent at the very start of the flight (make a note of the time to do each of these two legs) then; once back near ground fly around as normal and land at your normal battery level.

If you want to fly at altitude before landing, plan to be at ground level with say a 30% margin of time, so if you got 12 minutes safely with the climb and decent at the beginning, on the next flight, plan to be on the the ground in 9 minutes, deduct the accent and decent times from 9 minutes and whats left is a safe amount of time at altitude, again depending on conditions, a windy day can have larger differences in wind at altitude than a calm one. I've done a few flights at max altitude and the total flight time was not a whole lot less than one in which the total flight was at or less than 100 feet, but again I only would do these on calmer days.

PatR · Jun 10, 2018

If you ever have the opportunity to use a flight controller that permits adjusting the max climb and descent rate and level flight speed you should give it a try. It’s amazing how fast a large multirotor can climb, and how quickly they can descend and still remain stable. Gotta pay attention when you’re getting close to the ground though. They don’t bounce well...

Ty Pilot · Jun 10, 2018

Yeah, I've always felt the factory settings on climb and decent seem pretty muted, I've done a few full speed runs without GPS and yeah, its a different animal, I can only image what an uncorked H could do in the vertical.

NorWiscPilot · Jun 12, 2018

All I can say is the stock climb rate, with GPS on, is impressive as it is!

I had the opportunity to demonstrate the capabilities to a bunch of old golf buddies, while on the shores of a lake, with pretty good headwinds. Felt much stronger than the reported 11 mph winds.

Anyway, they asked for a vertical demo. It seems like it was only 20 seconds or so to hit the max (400 feet - U.S.). The actual time really doesn't matter as all I could hear was "Holy crap!" [Or utterances very similar.]

Mind you this was after the day's round of golf, and the 19th hole, and back to the lodge for more refreshments. The audience was primed to be impressed, if you know what I mean.

Jeff

P.S. For those wondering, the pilot did NOT participate in those same beverages. It is amazing how those indulgences are much less frequent simply because of ... "Hey, I might want to fly later today!" Wonder if that could be added to any "program"?

Photo · Jun 12, 2018

NorWiscPilot said:
All I can say is the stock climb rate, with GPS on, is impressive as it is!

I had the opportunity to demonstrate the capabilities to a bunch of old golf buddies, while on the shores of a lake, with pretty good headwinds. Felt much stronger than the reported 11 mph winds.

Anyway, they asked for a vertical demo. It seems like it was only 20 seconds or so to hit the max (400 feet - U.S.). The actual time really doesn't matter as all I could hear was "Holy crap!" [Or utterances very similar.]

Mind you this was after the day's round of golf, and the 19th hole, and back to the lodge for more refreshments. The audience was primed to be impressed, if you know what I mean.

Jeff

P.S. For those wondering, the pilot did NOT participate in those same beverages. It is amazing how those indulgences are much less frequent simply because of ... "Hey, I might want to fly later today!" Wonder if that could be added to any "program"?

NorWiscPilot, what's your view.....will it drain more juice from the battery to climb to 400ft than to descend to ground?

NorWiscPilot · Jun 12, 2018

Photo said:
NorWiscPilot, what's your view.....will it drain more juice from the battery to climb to 400ft than to descend to ground?

hi Photo,

Undoubtedly, under normal circumstances, it will will always take more energy to accomplish an ascent than a descent. Its the laws of physics, as AH-1G pointed out.

In my personal experience, I rarely notice a change in battery level (H480 voltage) during a routine vertical descend. If I am employing a glide slope, meaning my H480 is out a ways, it will consume more power as expected, as the flight path has a horizontal component. Not as fast a voltage consumption though, when compared to a 90 degree flight path (horizontal to landing point, vertical descend to land).

Of course, a couple things need to be kept in consideration:

1) a very slow descend speed will take up more juice than a rapid descent, simply because of the [extra] time factor.

2) if the descent encounters an updraft, then ALL bets are off! Same with the ascend!

Point two depicts the possibility of this being a "trick question"!

Footnote: what I have not observed, as yet, is to the change in the H520 power depletion, given it is displayed in percentage (real time) rather than voltage (user action necessary).

Jeff

PatR · Jun 12, 2018

I’ve got a 500+mm X8 and an 810mm hex with different FC’s that easily double the climb rate of an H. Both are a lot heavier as well. The X8 has the descent rate set up in two stages for a normal descent, starting at 10m/s up high and shifting to 3m/s below 20’. The part you have to remain cognizant of with both of them is that pulling the throttle full aft will reduce motor speeds to idle. Meaning both can literally fall out of the sky with the wrong throttle command.

Did that once with the X8 at 300’ where it rolled inverted and started free fall. Realizing what I’d done I went back to full throttle, and prayed. Luckily it flipped back upright at about 75’ and sank for another 25’-30’ before achieving a stable hover. That was the day I fell in love with Pixhawk.