Trex 600E in hopes to save on glow fuel?

[sherman89]

	Quote: Originally Posted by pipercub123
	Wow, so only 5 min flights can be expected? LOL, that's just enough to start having fun. Also, crashing and burning up both a field and heli wouldn't be too cool. I can just see images of the heli going down out of site. In the meantime I'm looking for it and see smoke, oh there it is! Imagine someone out west causing a wild fire by an rc heli. I'm sure they don't burst into flames every crash, but if they can get a good flame going that's a bit scary.

The 600e with a 6s-5000 pack will yield 4.5 minutes of mild 3-D and 5-5.5 minutes of sport flying. High temperature's is what kills motors ESC's and battery packs. Crash and burns are very rare, the class clown must have really augered in big time to get a fire going although I have had a few ESC's catch fire. If you keep the ESC below 110. the motor below 130 and the battery pack below 140 then things will last as expected. Do not exceed the 80% rule on the battery capacity and it will last as well. I have 6s-5000 packs approaching 200 flights, yes they are getting tired but they are still going and I have to reduce flight time to keep them in the pack inventory. I do monitor every flight with a temp gun and do let my packs cool to ambient and do not exceed 1C on the charge rate. If you fly a lot and baby sit your packs then you will get ahead of the cost of glow, but if you are an occasional flyer then glow is more economical in the long run.

[Gandalf_Sr]

IMHO Align were dumb to make the 600E a 6S system. The power dissipated in a resistor is I²R and power drawn is V x I (where I = current in Amps). What this means is that you can get 2000 Watts (a measure of effort where 1 HP = 746 Watts) by drawing 100A from a 20V battery (roughly 6S) or 50A from a 40V battery (roughly 12S); so, double the voltage and halve the current for the same power. So what you say? Well the real gain is that the losses in the resistance of any system are reduced by a factor of 4. I'll work that through for you...

If my total circuit resistance is 0.1Ω (Internal resistance of the battery + on resistance of the FETs in the ESC + winding resistance of the motor) then drawing 100A my losses are 100 x 100 x 0.1 = 1000 Watts, that means that HALF of my 2000 Watts is lost as heat in the batteries, ESC, and motor and I only get 1000W of power left to fly the heli.

Try that with 50A... 50 x 50 x 0.1 = 250 Watts so I still have 1750W left to fly the heli and a quarter of the heat in the system components.

You need a HV-capable ESC but it also doesn't have to take as much current. A lower kV motor and a different pinion are needed but this is a small price to pay for getting so much better efficiency.

OK, I know that we never fly helis at a continuous 2000 Watts but the above exercise clearly illustrates why higher voltages are better; less heat better efficiency, longer flight times.

[GMoney]

Try this out. http://crackroll.com/forums/showthread.php?t=2179 I hear rumors of a 600 with that 20 EI shoved in it. There is a guy in SoCal that is flying one but no production units yet. I like the 700G parts are cheap and they are made around a motor that cost less than 200 bucks.. Gas is GOOD! I also see rumblings of Align releasing there own 700G, I have yet to confirm though..

G$

Now if I can just get my gasser to run on the same mix as my 35%er one fuel can.. OHHH dreams!