Great scheme, really like the purpose built big E power. I'll take 2! Can't wait.

Doug B.

I really hope battery technology keeps improving. Is 4 minutes about what you get out of a electric plane of this size? My only electrics are in the 48" range, and they usually get about 5 minutes. So I can imagine with the bigger motor, servos, etc that one this size would drain a battery pretty quick. Plane looks like it flies amazing, like a big foamie.

Originally Posted by Wade

I really hope battery technology keeps improving. Is 4 minutes about what you get out of a electric plane of this size?

That flight video was heavily edited down to 4 minutes as you can see if you check it out again. Everyone was trying to be nice to Chris' new toy too. I would not have been able to control myself like they did.

Hey Doug... I think we're both thinking about the you-know-what Falcon carbon E on there? Gonna be silly!

All I know about it is if your a fan of light wing loading, electric motors, and ballistic power on an airframe that flies like a dream... Your gonna love this plane. Did you see how hard Tim was working the ailerons and rudder to control the plane in harrier? Yeah, I didn't either wink wink

It will be well within reach to expect 5 to 6 minute flights....

Originally Posted by Wade

I really hope battery technology keeps improving. Is 4 minutes about what you get out of a electric plane of this size? My only electrics are in the 48" range, and they usually get about 5 minutes. So I can imagine with the bigger motor, servos, etc that one this size would drain a battery pretty quick. Plane looks like it flies amazing, like a big foamie.

OK, I will try to answer this but it is still somewhat unknown. First, the plane is coming in at 19.X lbs. so with the XPwr 60 it has incredible power to weight. Thus unless you are in to high speed you can reasonable get 6 minutes, with a mix of high speed and other low throttle stuff 5-6 minutes.
Aeroplayin is exactly correct when he said it is edited way down, I think the one flight was nearly 7 when Tim just putted around......in the end like all electrics your flying style will dictate flight times, but with some management you can easily be in the 6 minute range with this plane due to its extreme light weight.
Jeff

12S 5500mAh at 135A peaks (6000W potential) means a 25C discharge rate. To 20% capacity, that means just under 2 minutes at WOT all the time.

Low and slow 3D flyers at 32% power average will see 6 minutes, and and guys leaning on the throttle a lot for a 38-40% average may only see 5 minutes. Increasing to 6000mAh means 6.5 and 5.5 minutes and should only add 5.6 oz bringing the plane to only 20.3 lbs -- still a 296 W/lb power loading.

But of course, if you are typically leaning on the throttle a lot for high speed XA, you probably should be considering the 94" MXS with a DA-70.

But for all of us that love the convenience and low end torque of electric power, and used to 5.5 minutes with bigger planes, this is what we've been waiting for an appreciate the fact that someone took the initiative to do this for the electric market.

I'm getting exactly 5 minutes to final approach to 3.73 volts per cell post flight on my big 14S electric 6600W setup to 127A, so that means I'm a 38-percenter. So I'll get the same 5 minutes on 12S 5500 and 135A and 5.6 minutes on 12S 6000mAh.

Just want to add here that I can go with my lighter 12S 5300mAh pack and bring this plane in at 19.5 lbs. Then put my Falcon carbon light prop on it, which pulls 36 lbs on my Rapala at 118.5A. I'll do 7 minutes at that discharge rate with a 1.85:1 thrust to weight. That's about the same silly thrust to weight as I'm getting on my 74 Edge with 3100W and the same flight time as 70A on 3300mAh.

I definitely wasn't down playing the benefits of electric planes, I absolutely love them. I've just never messed with an electric setup on anything bigger than a 48" plane. I was just curious if the bigger planes got roughly the same flight times as their smaller counterparts.

I'm usually ready to land after about 5 minutes anyways. This plane looks amazing, and it's good to see a purpose built electric plane that can be built lighter/

Sure... flight time is all about discharge rate or Amps per Amphour. So 6000W and 135A at 44.4v with a 5500mAh capacity is 135A / 5.5Ah, or 24.54C.

We then convert hours to minutes by dividing 60 minutes by the C, so 60 mins / 24.54C is 2.44 minutes for the entire 5500mAh at WOT.

So we need to then multiply by .80 to leave a safe 20% capacity in the battery, so 1.93 minutes -- and this is at WOT.

So if you are a 38% power average user on well powered planes like I am, then divide by 0.38.

So 5.07 minutes on a 135A system with a 5500mAh capacity.

It is true at 35A or 1035A.

How will an AGM60 pair with this aerocraft?

Looks great!

Originally Posted by Aeroplayin

I'm getting exactly 5 minutes to final approach to 3.73 volts per cell post flight on my big 14S electric 6600W setup to 127A, so that means I'm a 38-percenter. So I'll get the same 5 minutes on 12S 5500 and 135A and 5.6 minutes on 12S 6000mAh.

Aeroplaying - great info as usual, many thanks.

In terms of post flight voltage, what have you found acceptable enough to make a pack last a couple of seasons? You mention 3.73, I have been focusing on keeping it no less than 3.8 and since I really can’t get it perfectly there, I end up around 3.85. Feels to me I could get another 30 to 45 seconds of flying if I went down to 3.73...

The first thing I do is ignore the C rating on batteries and buy good brands with at least a 35C.

I also make sure my capacity enables a C under 25. So with a 135A system, we need a minimum 5500mAh. (135A / 5.5Ah = 24.5C)

If the cube loading can handle the extra capacity weight, I'd try for something closer to 20C - 21C but every 500mAh added to the capacity of a 12S system adds about 5.5 ounces, and this is the main attraction for me to an E-only airplane built light. I may actually get away with 12S 6000mAh.

A plane that is overbuilt to accommodate the vibrations of a 2-stroke engines is typically already on the heavy side so adding the capacity for the better C and more flight time is less possible if you want to keep the cube loading down.

Once I'm happy with the discharge rate, I try to balance when charging all the time.

I also vent the batteries to keep them as cool as possible because heat is never a friend to any electric power system component. So vent the motor, ESC, and batteries as much as possible.

I also look for batteries with 10 AWG wires on high voltage / current systems.

I also try not to store them with a full charge, but I have to admit that I'm guilty of leaving them stored fully charged for a while without realizing it.

Originally Posted by Aeroplayin

The first thing I do is ignore the C rating on batteries and buy good brands with at least a 35C.

I also make sure my capacity enables a C under 25. So with a 135A system, we need a minimum 5500mAh. (135A / 5.5Ah = 24.5C)

If the cube loading can handle the extra capacity weight, I'd try for something closer to 20C - 21C but every 500mAh added to the capacity of a 12S system adds about 5.5 ounces, and this is the main attraction for me to an E-only airplane built light. I may actually get away with 12S 6000mAh.

A plane that is overbuilt to accommodate the vibrations of a 2-stroke engines is typically already on the heavy side so adding the capacity for the better C and more flight time is less possible if you want to keep the cube loading down.

Once I'm happy with the discharge rate, I try to balance when charging all the time.

I also vent the batteries to keep them as cool as possible because heat is never a friend to any electric power system component. So vent the motor, ESC, and batteries as much as possible.

I also look for batteries with 10 AWG wires on high voltage / current systems.

I also try not to store them with a full charge, but I have to admit that I'm guilty of leaving them stored fully charged for a while without realizing it.

That's great info. What about the rest voltage - say 3.8 vs going down to 3.73 or a bit lower?