Hoverfly Maintaining Altitude Has Always Been A Chore With My HFP

[Earl E Adobtr]

I cut my eye teeth on HFP. I always thought this was pretty normal for fc boards in general when flying in wind - that constant moving the throttle stick up and down to keep the copter at the same altitude for the shot. I notice this is not the case when I fly with the NAZA M ver 2 - height stays pretty much the same (same frame for both fc's). So back to the HFP, which flies better than the NAZA M in wind and just feels like it's on rails most of the time: is this an HFP thing or do I have a defective board? Barometric sensor is covered with black felt and I fly mostly in AL and I leave height hold off because I've had a few close calls when it was turned on.

 

[octocine]

That's interesting. My HFP is very stable when not in Altitude Hold mode. I find AH works very well when there's no wind, but assumed that due to the changes in pressure with wind gusts it could not work very easily in wind. Also in AH mode the throttle works very differently with altitude hold when the stick is in the 40-60 percent range and you ascend when you go above 60 or descend below 40. Is there any chance that you might have these two modes switched on your radio? I can't think what else it could be other than a problem with the board. Good luck!

 

[Bartman]

Earl,

Felt may be too dense for the pressure sensor. Also, the NAZA, if my memory serves me correctly, uses a degree of altitude hold even when altitude hold isn't selected. It's programmed in. Hoverfly may have incorporated this type of routine into the firmware already, I'm not sure.

Most heli's that don't use altitude hold routines even during normal non-assisted flight will require some working of the throttle to maintain a steady altitude. Heli pilots call it "milking" the throttle, a lot of up-down on the stick. Coaxial set-ups may have problems if the hover power setting isn't quite making hover lift. I've had issues where the combination of props and speeds on the upper and lower motors wasn't quite making the right amount of lift so I"d always have a little too much or a little too little.

Try replacing the felt with some less dense open cell foam and see if it helps. Maybe someone else can elaborate on the firmware, I've forgotten at the moment if they changed but I seem to recall they did.

Bart

 

[Earl E Adobtr]

Octocine, I know the two modes aren't switched. I'm talking some pretty good drops in altitude with AH off and AL on - probably 4-6 ft. During the unscheduled descent it take quite a bit of forward stick motion to get it to reverse direction to the point where you think for a moment the battery may have died, then it just shoots back up and levels off. It definitely gets your attention.

Bart, I'll try foam. Yeah, I was pretty sure the NAZA had some sort of auto AH going on in ATTI mode. Does HFP GPS improve altitude hold with position hold turned on or does it totally rely on the existing AH barometric sensor based hold function?

 

[Earl E Adobtr]

I flew both boards fpv on the same frame today, at a grass flying field. HFP drops like a rock when a breeze hits it and would probably go all the way to the ground if I didn't give it a lot of stick in a hurry. I tried AH and in calm conditions and it held extremely well. But as soon as a breeze picked up, it started dropping and kept dropping until I bumped the throttle up a bit. It would be impossible to do fpv photography with this going on. Looks like this board is going on the shelf until I can talk to the guys at HF. I did replace the felt with open cell foam - not glued but wedged in between the board and top plate.

 

[octocine]

Earl, That is definitely not normal for HFP. I can't think what could be happening. It seems your throttle input is varying with the wind. I certainly have more than 4-6 feet of variation in AH when it's windy, but it's rock solid in manual. Good Luck!

 

[Earl E Adobtr]

Thanks otocine, that was the info I needed.