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A couple of Questions Q500

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1. Is the altitude that is displayed on the ST10+ AGL or MSL?

2. I lost the video stream back to the controller at about 1100 ft down range at 100Ft. Is that normal? Video did record however. Would a higher altitude have made a difference?

3. When in RTH mode and the bird enters the vertical portion of the landing does it somehow compensate so as to not enter the Vortex Ring?
 
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1- Altitude displayed is from the take off point.
2- You've done well to get that kind of distance. A bit more altitude can't hurt to try and regain the signal.
3- I would say... No. I've not actually tried to test it but I think the Q lands in Turtle mode when RTH is used.Next time I'm out I'll do some checking and see if it matters what position the speed control is in when in RTH mode.
 
1- Altitude displayed is from the take off point.
2- You've done well to get that kind of distance. A bit more altitude can't hurt to try and regain the signal.
3- I would say... No. I've not actually tried to test it but I think the Q lands in Turtle mode when RTH is used.Next time I'm out I'll do some checking and see if it matters what position the speed control is in when in RTH mode.

With regards to Question !, IF I take off from a hill 200ft above a lake and then leave the hill and fly over the lake will the Altitude then read the additional distance down to the lake. In this example 200ft?
 
With regards to Question !, IF I take off from a hill 200ft above a lake and then leave the hill and fly over the lake will the Altitude then read the additional distance down to the lake. In this example 200ft?
Nope. When you press the start button, the altitude is set to zero. That is the reference for the entire flight.
 
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Nope. When you press the start button, the altitude is set to zero. That is the reference for the entire flight.

To be clear, when I take off from a high point of land and lets say climb immediately to 100 ft the ALT will read 100 FT on the controller. Now I fly away from that high point toward a dropping terrain without changing my altitude, still 100ft, The altitude read out will still show 100 ft even though
i am now at a greater height above the ground than when I took off. Is this correct?
 
That's correct.
And if you drop below your take off altitude the box will display a negative altitude.

Jafo: In my example the bird did NOT descend but remained at 100 FT. The terrain below dropped away about 100ft so effectively the bird was at an actual altitude of 200ft above the ground below. In this case you believe the altitude readout on the controller will still say 100ft because the initial reference point was the take off point?
 
Guys, the Q500 4K has a barometer located in the GPS Module. Since we can't input air pressure data (a.k.a Altimeter) in the Tx, I think the Q uses the barometer to calculate altitude based on the standard pressure which is 2Niner.Niner2 inches of mercury which by the way its the pressure at mean sea level. I live in South Florida where our usual pressure is around 30.08 inHg and that is why I get a 10 feet or so error margin in altitude down here. I suggest you confirm twice about that altitude reset because it does not make sense to have that. If you took off from a 200ft ASL hill, how can the altimeter be Zero at that high? Unless the altitude shown in the ST10+ is AGL instead and the Q500 is using the GPS data to calculate that. Anyway, this is just my $0.02 about this topic. I hope this gets clarified as it is an important thing to figure out. We all want to know exactly how high we are flying, right?
 
One important thing to note is our Q has a 400ft altitude lock by default. So, if the Altimeter was reset to zero every time we Start the engines, what about we go to the top of a 300ft building and take off from there. Will we be able to go up another 400 ft? Makes no sense as we will be reaching 700ft high without the lock to engage.
 
One important thing to note is our Q has a 400ft altitude lock by default. So, if the Altimeter was reset to zero every time we Start the engines, what about we go to the top of a 300ft building and take off from there. Will we be able to go up another 400 ft? Makes no sense as we will be reaching 700ft high without the lock to engage.

If the bird has a barro sensor, even though we cannot correct it for current barometric pressure just prior to takeoff you are saying that if I am taking off from a point that is 200 ft above sea level the altitude readout on the controller should read 200ft prior to take off?
 
If the bird has a barro sensor, even though we cannot correct it for current barometric pressure just prior to takeoff you are saying that if I am taking off from a point that is 200 ft above sea level the altitude readout on the controller should read 200ft prior to take off?

In addition, my take off point is about 700 ft above sea level. Prior to take off the altitude read out in my controller says about 1 ft so it appears to be reading height above ground at that point or, as Steve said, just resets the altitude readout to 0 at that point. If that is the case I don't understand what roll the barro sensor plays?
 
Okay folks. You're trying to make this way more difficult than it is. The altitude readout on the ST10 or the ST16 is derived from a barometric altimeter which is a rough measurement of altitude. When you press the start button it is set to 0. If you fly 100' above that point it will read 100'. If you fly a mile in any direction from there it will still read 100' until you change the altitude you are flying with the left stick.

BTW, the only time the reading is precise is the moment you start the motors. After that there can be considerable drift in the reading caused by wind, temp or the way you hold your tongue. This is not a precision instrument. It can be 10-20' in error after you fly for awhile.
 
Okay folks. You're trying to make this way more difficult than it is. The altitude readout on the ST10 or the ST16 is derived from a barometric altimeter which is a rough measurement of altitude. When you press the start button it is set to 0. If you fly 100' above that point it will read 100'. If you fly a mile in any direction from there it will still read 100' until you change the altitude you are flying with the left stick.

BTW, the only time the reading is precise is the moment you start the motors. After that there can be considerable drift in the reading caused by wind, temp or the way you hold your tongue. This is not a precision instrument. It can be 10-20' in error after you fly for awhile.

Thanks for that Steve. So if on that same flight I land at a location that is "lower" than 100 ft the altitude read out will indicate a minus - something. Is that correct?
 
Thanks for that Steve. So if on that same flight I land at a location that is "lower" than 100 ft the altitude read out will indicate a minus - something. Is that correct?
Yup. It will show a negative altitude.
 
I think the programmed descent rate is slow enough to avoid VRS. The only time I've seen the Q enter VRS is with carbon fiber props and under manual control.
 
I think the programmed descent rate is slow enough to avoid VRS. The only time I've seen the Q enter VRS is with carbon fiber props and under manual control.

So when in RTH mode the descent rate is about the same as a manual descent?
 
Steve, the Q500 is programmed to ascend at up to 9.84 ft/s, and in order to avoid entering in Vortex Ring State, the descent rate is locked up to a maximum of 6.6 ft/s in Manual or Auto landing modes. In the metric system. that is around 3 meters per second when going up, and around 2 meters per second when coming down. Yuneec estimated those were the safest positive and negative vertical speed for the Q.
 
Now.. going back to the Altitude calculation topic (question 1). The Q500 DOES KNOW both altitude measurements and even calculates a third one, which is the one you see in the controller.

For example, the barometer sends its information based on Mean Sea Level air pressure (29.92 inHG), the GPS Module sends data in Above Ground Level, and it does so by using 4 or more satellites and calculate your distance at different angles. Then it puts that data in a 3d space and thats how it achieves your altitude above the ground.This is a really long topic in its own. Google how exactly does a GPS calculates altitude and you will be reading for 4 hours.

And then... Your ST10+ shows a different altitude than those provided by the GPS and the Baro. The Altitude you see in the Tx is a relevant information that comes from the GPS.
If you want to get technical in this, it will be something like saving baro and gps data in two different variables. Creating a third variable with 0 assigned to it. And then its all about keeping track of the changes of the GPS data and updating the third variable proportionally. So, THAT third variable is what is being shown in the ST10+. That's why sometimes it shows negative altitude when you go lower than the altitude you took off from, which I personally think its stupid to do so, but Yuneec might have its reason for this.

I would have done it differently. I would have shown the Q500 GPS data directly to the controller and problem solved... Or even better, I would have included an option for the pilot to switch from MSL or AGL if he or she wishes to do so.

So, now that we know that the Q used the GPS mainly for calculating the Q500 altitude shown in the ST10+. What is the barometer for?

Well, as long as the GPS module is ON and working properly, we can say its redundant. However, when GPS is not available, that's when the barometer comes into play. But I bet that altitude will indeed be in MSL.

The altitude lock is based on the GPS altitude. Thats why we can go to a city that is 500ft above mean sea level and we can still fly up 400 ft more. Makes sense because the FAA restriction is for 400ft above ground level.

This is my though on all of this altitude calculation topic for the Q500. I would love to see the programming lines of codes the Q uses to understand way better how it does things.

Thank you for your explanation. I find the "altitude" subject interesting. Our Q500 have a surprisingly large amount of tech in them. I enjoy learning about the capabilities of these machines.
 
The Altitude you see in the Tx is a relevant information that comes from the GPS
I'm curious where you found this information. I've flown the Q500 for a very long time and have never seen any documentation that would suggest the altitude is derived from GPS other than speculation.

So I repeat.........altitude is derived from the barometric altimeter. Calculating altitude from GPS can be more erroneous than that derived from a barometer.
 

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