Anybody actually fly with two 450 sized batteries?

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I built my first 425 a while back and tried to fly it on two 2200mAh 3S in series and it was hell on the batteries. At the time, I attributed it to the quality of the batteries I was using (E-Flite 20C I got with my Blade 400). I quit flying it as a 425 and stretched it to 500 on larger 6S batteries.

I recently picked up another 425 and gave it a flight on my Turnigy 2200mAh 40C batteries and after just a short dial in flight, the 40C batteries were unacceptably warm.

This prompts the question... Does anybody actually fly the 425 on 450 sized packs? What power system are you running? What head speed do you run? What kind of flight times are you getting?

The power system on the first 425 was Align 500L 1600kv motor and 75A ESC. The new 425 is TonicX Z15 1620kv motor. Both times gearing was 13T pinion, 50T front main, 19T one way, 61T rear main. I don't think I am running head speed all that high. The 425 manual calls for a head speed of at least 2600 RPMs for the standard tail blades. The head speed calculator suggests my head speed would be 2733. I know I run my Trex 500 higher than that.

[Jerrymac]

Well, I have never tried running 450 sized packs in my 425 so I really can't help you there. I did maiden my 550 many years ago with 450 sized packs and it was not really too hard on them, although the flight time was only 4:00, but, the 550 runs a much lower head speed.

The 425 is basically a short version of the original 550 and I don't think Gaui took head speed into consideration when they stated that it will run on 2x3s 2200mah batteries.

I modified the front of the frame on my 425 and originally I ran some old Mega-Power 6s 2500's on it. Flight time was only about 4:00, but I run a head speed of around 2900 to 3000. I think the newer batteries are getting better though. I now use GForce 6s 2650's in it which are slightly lighter, and get 5:00+ flight times. I use a Tonic-X Z20-1470kv motor and stock Gaui 50A esc.

Personally, with the higher head speeds, I just don't think the 450 sized batteries are up to the task. Try running a pair of them in your Trex 500 and see what happens, lol.

Sorry I can't be more help.