Base

Based on what I know so far about Protos in general.... My Mini has a stock ratio of 15/120 on pinion/main pulley, which is probably good for 6S-1300Kv motor, but being as I'm running 3S, I use an 11T pinion (pulley) to drop the head speed and use a 3500Kv motor. I get a solid 5 minutes down to 25% to 30% capacity of the packs with head speed around 2800-3000 rpm depending on what throttle curve Jm using.
Per similar size and weight helis using roughly same size packs should get close to same flight times unless head speed too high or gear ratio too low and motor is not running fast enough.
Batteries in general loose capacity as temperature drops. Keep packs as reasonably warm as possible before flight.

 

Good advise @Beaver. We have some pretty sciency types on this forum. What do you think @simon ? Also @Manyc is pretty switched on and @thedude. @HungryHungryHippos ? @Geena? @mr_squiggle ??? Many other knowledgeable people as well. Just maybe we can nut it out.

 

I don't think you will ever get 20 minutes out of a 700 size heli, especially with the load of a decent camera. You would be better going with a drone of some type. A mate has an align 480 (see below). I'm pretty sure he can get over 30 minutes on that (he doesn't fly with a gimble or camera), so you'd have to get over 20 minutes. There are also no belts on this drone either so stiff belts will be no problem. I think the only option if you want maximum flight time (regardless of temp) is to fly it at 6s so your head speed is like 900 rpm, you might get 10 minutes with a good 5200 6s (that's just a wild and crazy guess. Maybe less (like 8-9 minutes). But not 20. I don't think any configuration in any temperature will give you 20. Batteries don't like the cold either, this will be a big factor in determining flight time as well.

Cheers SImon

 

ok.. looks like the ones you have used in the past are designed to be camera ships. running 800 size (well the joker is the one I looked up) in order to get something along these lines you would have to stretch to 800.. find the largest packs, and then gear for round 1200... being this is designed for 3d.. you would have to tune to be very very docile..

That said I would agree with Simon.. all the heli camera ships have been replaced with drones, and for good reason, they offer a lot more flexibility.

can you list what motor/esc/gearing you are using, as well as what battery and blade size?

I have acheieved 10 min flight times on heli's, but not carrying any loads, and have been super low headspeeds...

 

I agree, 20 minutes is asking alot from even a conservatively geared heli. The most I've ever achieved is 8 minutes from a 450, but that was pushing my packs a bit too far of a discharge. High-mAh packs will help, but at the expense of power to weight ratio if they are too heavy.

 

Now that I had a minute to think about specifics.....
At one point, I was running a 3S-3200mAh pack in a 450SE-FBL loaded near 900g, running a Turnigy (Scorpion clone) H2223-3500Kv, 45A ESC, 11/150 main gearing, and was running an average of 2800rpm head speed on cheap 325mm blades. In that configuration, I remember hitting the 10 min. mark a few times, but the pack didn't take to it much from me pushing it too far and consequently- one of the cells went bad.

 

20 minutes out of an electric 700? You might get close if you run it on 6s with a 20,000mAh+ battery, and low head sped, but I think that`s a bit of a stretch. The most I have ever gotten out of my X7, running it at 1550, was about 8 minutes. If you want extremely long flight times from a collective pitch helicopter, my suggestion is to get a gasser. 20+ minutes on a tank of gasoline, but the will be more vibrations ( which may or may not affect video quality) in a gasser than there will be in an electric...and you`ll have to have more support equipment. You might be better off to just stick with a multi rotor platform.

 

Thanks folks for you very informative posts. I am new on this site and truly impressed by how many knowledgeable flyers are willing to help. It seems I have not explained my problem well enough, Finnish, not English is my mother tongue. We get approx. 24 minutes flight time with 10.000 mAh Lipo with all our 1800 mm copters (new Lipo).

Vario, Centurio, Mikado and Minicopter Joker at around 900 to 1000 RPM.

What I am concerned about is that with the same brand of motor - Kontronik – the same servos –Futaba brushless low Volt - and the same autopilot, DJI NAZA H and DJI ACE ONE and the same Phoenix ESC, the Protos Max v1 and v2 I recently acquired, at least in cold weather gave drastically inferior flight times. Measured in-flight by telemetry the Amps at hover of both Protos copters were twice as high as the other copters: roughly 60 Amps versus 30 Amps, which of course drops the flight time to half that of the others. (did not fly them in the cold to see the end result, felt the measurement done 3 times with the same result made that unnecessary) It might be, that the toothed belts of the Protos are the reason as they have more pronounced bends than the belts in the other copters and might also be of a material that stiffens more in cold weather than those of the others. What I actually was hopig for was someone who has measured the hovering Amps of a Protos Max 1800 at appr.1000 RPM in decent temperatures.

Thanks again


Kaarlo von Freymann Helsinki Finland, founder of the drone company back in 1968 you can see here http://avartek.fi/?page_id=166