When is heavier better? Stability - vibrations - discloading?

C

cman319

Member
Hello all,
I am a newby with some tricopter experience and now flying an aluminium hexa + naza + gopro (Nex5 is coming next). I read many interesting things on this forum about best configurations, building a multi for your specific camera/weight + flighttime needed etc and now that I am flying my hexa I wonder how I can make it better / optimize it for my future Nex5.. (photo + video).

Xcoptercalc (hexa, 10x5graupners, tiger 800kv, 4A4Sbatt) calculates 39% throttle and 11.91min hover time, this is conservative since I can fly around for a full 12min.
However, if I now mount the future Nex5 (+FPV) should I rather go for a sturdy (expensive) camera mount and good servo's and fly at say 2600gr, 53% throttle, 8.25 min or try to keep it lighter at say 2300gr, 46% throttle, 9.46min?
Or go lighter + bigger battery? In other words what is a good "disc-load" for a given prop size (in this case 10x5)? Did anyone properly compare different "loads"? (with good I mean smooth flight, no vibrations).

Another question I have is how useful rollcompensation is for still photography? I mean how often do you really take photo's with sidewind?

One more: did anyone ever successfully make square arms more aerodynamic under the props, is the extra weight worth it? Does it maybe also give less vibrations?

Any input welcome

Mike
Cheers from a sunny Ferney-France
 


yeehaanow

yeehaanow

Member
I can't speak to a hexa, but I added a 2.5 lb weight to my quad, (around 6-7 lbs AUW) and it really did not seem to fly any smoother in the wind. Maybe even less-so. That was with the 11/4.7 props. The esc's were significantly warmer though.

It's great to have roll compensation in photography, but since a multi will mostly fly flat, and you can take multiple pics and choose the best one and/or correct in post, I'd say you could easily live without it.

I have square arms on the quad frame and getting no vibrations with the camera basically hard-mounted to the frame. Just good balancing of props. (10x5 Graupner)
 

C

cman319

Member
thx yeehaanow,
you are right, instead of spending time on forums I should simply do my own testing and find out what suits me best.
I will do a direct hexa-6 to Y-6 comparison, try different props and weights and try to make things more aerodynamic until I get good images and smooth video.
have fun everybody.
Mike
 

K

koolkiwikat

Member
I fly a hexa AUW between 7-11 lbs, 12x3.8 props, I have tortured the rig by flying in some full on gusts/winds with dummy weights, its amazing how much it can handle and now that I know the limits of what my rig can handle if gives me confidence when I need to shoot in varying conditions
I have done the same with my smaller quad, 3 lbs, I had to fight almost full roll/pitch lock to move against the wind, its a whole lot of fun as long as you keep it from smacking the ground, its worth knowing the limits

both are smooth as silk in minimal wind, hexa handles ALOT more, If it is windy I shoot burst mode on my NEX5, tweak up in PS, I fly a 3axis gimble with retracts on my hexa

My next hexa will be 10" props on the DIY xaircraft frame, more then enough for a NEX5
 

matwelli

matwelli

Member
i built a quad for a customer, the project got a bit out of hand, with fpv and two cameras, all up weight ended up being 2.6kg (5 point something lbs) on 4S 5600 mah lipo, 10 by 4.5 props

it was absolutly rock solid in the air, required 75% throttle to hover (75% throttle = 50% total power) but the most stable machine in breeze that i have flowen
 


matwelli

matwelli

Member
Sure

75% available voltage times 75% available current = 0.75*0.75 = 0.56 , its not 100 percent accurate, as every motor responds differently, but its between 50 and 60% of your total thrust happens at 75% Throttle,
 

J

jes1111

Active Member
Mmm... now I'm perplexed. Assuming throttle stick all the way down is "0% throttle" and all the way up is "100% throttle", and that my rig is carefully calculated (eCalc-style) to hover at "50% throttle", will my stick be half way (i.e. dead-centre on its total travel) at take-off/hover? Your statement implies (to me) that the stick would be three-quarters of the way up.
 

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