How do you judge 400' ?

[Vermiform]

Just realized I have no idea how high 400 feet looks from the ground. Any tips or pointers? Could I even see my 200 qx from that far?

[Nelsonisms]

I guess you can say that an average building is about 10-12 feet per floor, so it would be around the height of an average 30-40 story building. I have altitude telemetry on my QAV400 so I've done that experiment with it hovering at 400 feet. At that height I can barely make it out and most certainly wouldn't be able to keep orientation without FPV, so a 200 sized quad is going to be essentially invisible at that height from the ground.

If you Google "list of tallest buildings in [your city]" there are some good Wikipedia articles that list buildings by height for reference.

One Congress Plaza in Austin, TX is 390 feet.



The Ashton apartment building it Austin, TX is 412 feet tall.



The Spring in Austin, TX is 433 feet.

[Vermiform]

So a rule of thumb for my 200qx quad and smaller (and my aging eyes) is that as long as I can see it enough to maintain orientation, I should be ok.

I guestimate my visual hard ceiling is going to be about 200 then.

[Nelsonisms]

That sounds like a reasonable rule of thumb. I don't think you'll have to worry about it with craft that small. I also fly a 2 meter sailplane and even it gets pretty small up there at 400 feet.

[Vermiform]

Originally Posted by Nelsonisms

That sounds like a reasonable rule of thumb. I don't think you'll have to worry about it with craft that small. I also fly a 2 meter sailplane and even it gets pretty small up there at 400 feet.

Thanks Tejas. Appreciate the quick response.

[jbrandt]

I would say that if you find yourself saying "man that thing is getting pretty small" and your squinting at it, you should come back down...

I think that's fairly independent of the size of the heli too.

Think about the size of even a 700 or 800, and how it's smaller than (I'll even give you that it's the same size as) one of those buildings' windows. Try to maintain orientation now...

Here's a rework of one of the buildings in Austin with a 700e sized somewhat appropriately. I think I'm even being generous, scale wise, and it's on a white background... Granted, it gets a little pixelated...

[Nelsonisms]

Hehe....Nice. A+ for effort.

[Psywarrior]

Geofencing. On my F450 with Naza M V2, I simply set a 400' ceiling. I have never taken it to that height though. Even with all the lighting it gets hard to see orientation above 200. Since I added FPV it's easier, but I still haven't maxed out altitude because the QX made me paranoid about wind at altitude.

[Vermiform]

Yup. FPV especially with an OSD would make things much simpler.

[AntDX316]

A calibrated and working telemetry GPS elevation setup.

I think the 400 feet limitation was intended for FPV pilots with GPS and telemetry capability.

As with most of the knowledge in the world they leave super specific details out and leave it be. The afterlife is the biggest most important one.

[setishock]

If you're talking about an altitude cap, In the naza v2 and the Phantoms above the Phantom one, has that in the set up. When the barometer reads where the cap is set, it just won't go any higher.

As for good ol mark I eyeballs my rule of thumb is when it appears to be the size of a soda can end, that's plenty high enough. I have an Estes rocket altimeter that I strapped to the leg of a Phantom. I flew up to what I though what different altitudes and checked what the altimeter read out. After about 50 flights I learned what my gals look like from different altitudes.