Measured power.

[akent]

I recently bought a 'Watts Up' power meter, as I had too many questions about what power is needed for what.

I will try to post the findings as I find them here.

If anyone of you have measurements from a power meter, please post them here!

The format preferrably should be:
1. Helicopter
2. Motor and pinion
3. Esc
4. Battery used
5. Radio
6. Cyclic servos
7. Gyro
8. Tail servo
9. Throttle/Pitch curves, if possible
10. Headspeed, if known
11. Flying style for the test
12. Flight time

Obviously most of the power will be used by the motor, but a fair amount can be used by some electronics, especially if the BEC is linear.

I think this could be a very informative thread, if we all can contribute!
Best,
Kent

[akent]

First up:

1. Exi T450
2. Scorpion HK2221-8 V2 - 12t pinion
3. Hobbywing Platinum 40 amp
4. Zippy 2200ma 3s 30c
5. Spektrum DX7 - AR7000 rx
6. HS-65HB
7. CNChelicopter G401B
8. Futaba S9257
9. Idle 1: T: 80-inh-60-inh-80 Pitch: linear
10. HS: 2,600
11. Hover, fair amount of Slow FF and a few full throttle punches.
12. Approx. 6 minutes

Used current: 0.902 amp hours (way less than half of the battery, and it took really close to this to recharge it!)
Used power: 10.1 watt hours
Final voltage: 11.47
Min voltage: 10.75
Peak power: 315.1 watts
Peak current: 28.65 amps

I will try to get the same measurements with idle up 2, which is 100-inh-80-inh-100 with right at 3k rpm headspeed.



Best,
Kent

[akent]

Here's idle up 2.

The current was considerably lower than I expected.

This was a similar flight to the one above with the same flying style and number of full throttle punches.

Used Current: 1.2 amp hours
Used Power: 11.5 watt hours
Final voltage: 11.2v
Min voltage: 10.7v
Peak power: 350.8 watts (almost 1/2 horsepower!)
Peak current: 31.6 amps

The headspeed as mentioned above is 3,000 rpm with this setup.

So, a 30 amp ESC really is enough for the Scorpion motor! I was surprised.
Best,
Kent

[Solitaire]

All good stuff, Kent, especially for us stats nutz. Now, all we have to do is outfit everyone with Watts Up meters. ;D

On the 30A vs 40A ESC...the wire size is heftier on the 40A, thus less resistance. Wonder how your figures would look like using a 30A? I'm betting the amperage would be a tad higher and it's still nice to have the cushion of a 40A.

Nothing to back that up, at this point. Maybe someone with a 30A on their 450 will post up some stats.

[akent]

Sol, I still have the Volcano 30a ESC. I think I'll hook it up to see.
It will be interesting, I think!

I completely agree that ESC overkill is a good thing, from what I've learned.

I know it's not relavent to this board, but I built up an ARF Eflite plane with all of their recommended parts. This was a brushless .10 (nitro equivalent) motor, 40 amp ESC, and the same batteries that I use with the 450 heli.

So, at full throttle with the recommended 12-6 prop, it pulls 53 amps and shuts down the ESC after maybe 20 seconds!!!!!!!!!!!!!!!!!!!!!!! What kind of carp is that??

I am completely blown away by them.

I posted this as I installed the Watts Up in it after it kept shutting down. I have never even flown that thing! It's really annoying when you use everything someone recommends and it is garbage!

Ugh.
Kent

[Solitaire]

Well, "annoying" isn't exactly the word I'd use.

I see the kit comes with Spektrum DS75 servos. See if you can get an amp draw on those. I've heard they draw a lot more than other servos of comparable size. Other than that, a different prop or ESC, but that's not the point. All the suggested components in the kit should work, especially when you pay premium prices for EFlight products.

Interested in what you come up with, both on the Bipe as well as the 30A ESC on the 450.