1 hour 20 minutes
- APM 2.5 takes the world record for Multi-Copter Duration of Flight powered by a rechargeable battery. [note:  records also exist for hover that can occur indoors and take advantage of ground affect]

Flight Requirements:

- Distance > 1 kilometer

- Minimum elevation from ground the greater of 2 meters or two prop diameters (no ground affect)

- Lands within 50 meters of Launch

- Minimum of two way points > 0.25 km apart

- Altitude Climbs: Two climbs > 100 meters each

- Ends before voltage drops below recommended minimum level for recharging

- Flight over ground that does not vary more than + 20 meters in elevation

Actual Flight

- Distance: 1 - 2 km

- Min elevation 2 meters

- Ended at start

- Three way points with two 0.3 km apart

- Two climbs:  126 meters and 112 meters

- 13.06 volts left with 10 volt recommended minimum

- Ground + 10 meters

Time:  > 1hr and 20 minutes (81.43 minutes)


- Octa 2XQuad 6Up+2Dn (wanted to fly something novel that would show off the flexibility of APM 2.5)

- 3.18 kg AUW

- Li-Ion battery

Attached are the flight logs.  Later I'll provide:

o Video

o Earthview of flight

o Altitude gains

o Details of the copter (design and weights)

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parts are orderd and we will see how it goes a month from now....

...and this new big T-motor still did not show true potential bcs nobody can use them at 12S battery because there is no good ESC

T-Motor Recall Announcement.
December 27, 2013

Dear T-Motor Customers,

Hereby we inform you that today we are voluntarily recalling 172sets of T65A & T70A pro ESC products, which were sold all over the world via our distributor, email order and online shop since July 2013. We are taking this precautionary action after learning that T65A &T70A pro ESC exist risk of RPM lost or stall when switched from 10% throttle to 75% throttle abruptly and repeatedly with impertinent operation. This situation will be happened when the ESC matched with U11 motor and 28 inch propeller under 12S. We will prevent possible failure and upgrade latest software for free.


Not to worry.  The 2hr flight was a facade.  Cost isn't a factor.

I checked the efficiency of the U8 motors and prop combinations per Tiger Motor actual test specs and compared that to other Tiger Motor rotors.  Given the U8 large weight, the net efficiency (efficiency after lifting the prop, ESC, motor, and added structure) is excellent but nothing to make a person want to buy these rotors at $700 each (motor+prop+esc).

Fortunately, you can do as well with lower cost, lower weight rotors.

I know that some people are enamored by this pilot and flight, but I wish the pilot hadn't used the lee side of a building on top of a hot house to get a significant portion of his lift. The sad part is this might mislead people into making a severe financial error.  This is one reason why flight needs to include movement and needs to be filmed.

We can and will get to a 2 hr flight.  But it will be done via real innovation not misleading tricks.

If anyone gets angry about this I suggest turning your anger to good use.  Contact Ferdinand and get him to move the copter over fairly even ground on a windless day making two 100m assents.  Words mean nothing. Show me.  Show us.

Ok Forrest, but why don't  tell him that yourself?I only enjoy reading what Ferdinand writes about multirotors,and watch his nice videos from time to time...everything above hour of flight is very impressive for me and I don't rally care if he get 10 -15min bcs of something...but he is also a very good mathematician and in physics too so he can prove you how he get that result...I honestly think it will be good for you and all this long time flight thing,to join discussion on RCGroups....but problem is you can't bcs he just close his thread(as of 18.1.14) over there exactly from the same reason;people was always tried to find him mistake and tell him that is not possible


..and also agree I will never need or buy 700$ motor with gigantic 28-29 inch prop...

Thanks for the Heads-Up there Emin .. not to worry .. I've got 10 RcT 20a opto's coming in .. rich enough for my blood amigo.  700 bucks would buy a nice 200mhz two channel DSO (or 3/4 of a tank of propane :-), and that's Per Rotor.  Pancakes have always been notorious for flaking out when "Pumping" the throttle .. they weren't designed for that.  Simon(k) says .. you gotta be kidding ... lol

That battery you quoted earlier .. you might want to re-evaluate.  At only 190.76 wh/kq it's still a pig to lift, and that's at gross calc .. 100% discharge*.  At 80-90% it's even gonna look worse.  As I recall these are the same batteries that Ferdinand got some pre-production samples of a couple months ago.  Their only real advantage is that they are only 15C as opposed to the more commonly found (heavier/thicker) 35C+ Heli batts, and they are plug an play so to speak.

True enough you'd have to go to an 8P in a Pani-Pak to get that 15C, but you shouldn't need that high of discharge rating for anything of moderate build flying efficiently.  16 Pani's @47 grams is still inspiring .. but they ain't cheap either.  I'm more inclined to go with 3S5P for my MT4008's here.  Tiger had specs for 3S for these motors posted online (20 months ago) .. until they got into the Propeller business.  Now (sadly) only their own cork filled CF props running 4S minimum are spec'd in with their motors, and they Are Expensive.  Cheers!

"Women are like elephants. I like to look at 'em, but I wouldn't want to own one."  W.C. Fields

*16Ah x 14.8v = 236.8wh / 1.241 kg = 190.76 wh/kg (gross) .. my math OK?

Some Multi-Rotor (Lidar) Kandy http://www.youtube.com/watch?v=Nq3ZQxUiVWA

eh...plenty of time till new GensAce batts get to the shops around world(1.4)...now they offer discount on them but its almost impossible to convince them to ship you batt so u can only do in store pick up...what a shame....till than I will experiment with some cheap Chinese 10Ah 4S 905gr.batts 2 connected in parallel


*16Ah x 14.8v = 236.8wh / 1.241 kg = 190.76 wh/kg (gross) .. my math OK

hm,I am not best at math but

16Ah x 16.8V(4x4.2) = 268Wh / 1.241kg = 216,77 Wh/kg

and in this moment I guess only max amps ids near...

Well that's why I asked .. sounded kinda low .. I stand corrected.  That German eBay site sure has a much bigger selection of 10C 12C 15C Lipos than what I see offered over here like on Hobby-Partz.  Cheers!

First,be careful with no name batteries from e-bay..best thing is to not expect to much,specifications often not what they claim.....second,i am no expert for e-bay but german or not I have same password for german and English Ebay so I think u can order same way,all is coming from China anyway....also I hope you are aware Ferdinand andf Forrest and other long time flight multis using custom made Lion batts and normal lipos with that energy density just don't exist yet and I need a bit more than 10-15A for carry useful weight.

About ESC...I flashed mine with BLHeli soft,will see how they work with 18-20 inch props and pancake high pole motors...

But new video from Ferdinand show us how you can build useful x8 multi with U8...what a beast


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