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E-Sky › How to calculate (estimate) flight time
08-07-2009 01:53 PM  8 years agoPost 1
stocky

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Taxachusetts

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Without test flying..

How do you estimate the expected flight time from a Lipo.

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08-07-2009 02:14 PM  8 years agoPost 2
Heli_KV

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Ottawa, Canada

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I use:

http://dhrc.rchomepage.com/calcAdvanced.htm

Bunch of useful and not very much information.

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08-07-2009 06:15 PM  8 years agoPost 3
Gregor99

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Western Wa

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I used to take the mah consumed for a given flight. Then calculate the average mah per minute. Then use that number of calculate how many minutes until you get to 80%. I had a formula in Excel that did most of this.

Now I use BruceW's tool HSCALC. Do search for "Ultimate Head Speed Calculator" on the other site for the download.

Revolectrix Beta Team

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08-07-2009 06:29 PM  8 years agoPost 4
stocky

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Taxachusetts

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Greg,

I have the BruceRC calc,

The key thing was without test flying.

I am looking at doubling up my 6S 2650 pack and running them as 12S in my TT550.

I wanted to know how long FT I would likely get doing this.
It looks from Heli_KV's link as though I need know the average amps to calculate the time.

The motor and ESC are pricy and if I can only expect 1 min flight time I'm not going to do it.

Pack size is not an option, they exist from my 500.

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08-07-2009 06:58 PM  8 years agoPost 5
Heli_KV

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Ottawa, Canada

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It looks from Heli_KV's link as though I need know the average amps to calculate the time
No, you do not. Average amps are CALCULATED, if you put all heli parameters. It gives pretty accurate flight time. You can play with a whole bunch of parametres there. It is not that easy to use this calc for sure and it takes time, but for the flight time and amps draw estimated, you really need to input all heli parameters: weight, rotor size, efficiency, rpm, battery capacity, resistance, ESC, motor, gears, etc. You can ommit some parameters (actually to go with default), but essential parameters are vitally important for what you want. You can try simplified version though.

The best start, if there is heli which you have, click that button and default parameters for it will be filled. Then you can play with what you have. And...you can have different models of calculation there! You can even set elevation above the sea and see how it affects other stuff. I use it all the time, when I need to get an idea what to set onto heli. This is a tool I use when I twick HBK.

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08-11-2009 04:46 PM  8 years agoPost 6
dyuen888

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Brooklyn, NY - USA

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Hi,

Why esitmate? - connect a battery monitor - it has a visual and audible alarm to warn you went to land. when you recharge your battery the charger can tell you how much power you used up.

Check the alarm on each fly by

http://www.helidirect.com/maxpro-ba...ries-p-8159.hdx

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08-12-2009 01:56 AM  8 years agoPost 7
stocky

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Taxachusetts

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I can assure you I will not see or hear that alarm on a TT550 running 12S. Those things IMHO are worthless, timed flight is the only way.

The reason I am estimating is that the Heli does not exist so I cannot monitor it. I want to estimate the Flight time to see if the use of 2 packs in series gives enough flight time to make the conversion worth it.

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08-12-2009 06:55 PM  8 years agoPost 8
dyuen888

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Brooklyn, NY - USA

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Ooops.. My bad. This was in the Esky forum and didn’t see your requirements… But you be surprised I have heard the alarm above the 600 nitro flying near-by. I also connected a larger LED.

Well here is my guess-imate – keeping everything simple, you have two factors:
1. The capacity of battery
2. The item that is consuming the battery - the motor. Yes there are other heli factors but the bottom line is that it’s the motor that is consuming the energy from the battery. Lets use this example:

The battery is 6S battery 2650mah is 22.2 volts 2.65 amp/hr
Total energy stored = 22.2 x 2.65 = 58.8 watt/hr.

Since the item consuming the battery is not a pure resistor (i.e. heating coil) but a motor and the voltage will drop as the battery is draining we need to multi the total by a Power Factor (PF) In this example I will assume a value of .9 so we don’t really have 58.8 watt/hr but 58.8 x 0.9 = 52.9 watts/hr. We’ll use a rounded number of 53 watt/hr.

A typical 500 size motor consumes a max energy of about 1200 watts @ full throttle. The max watts is always listed as part of the motor spec. I will assume that we are not flying at full throttle but around 70% - So 1200 watts x .7 = 840 watts. Meaning every second the heli is in the air it is consuming 840 watts from the battery.

Again back to our battery of 53 watts/hr. This battery can be drained at

53 watts for 60 mins
106 watts for 30 mins
212 watts for 15 mins
424 watts for 7.5 mins
848 watts for 3.7 mins – my Guess-imate, some where near 4 minutes

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08-12-2009 08:36 PM  8 years agoPost 9
Melnic

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Columbia, MD,USA

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Stocky, I have the -K11 kit that has the 75A ESC and ACE BL motor.
I run a 6S 5000mAh Zippy.

I set my timer for 7 minutes of sport flying and I land and deplete around 70% of my pack. If I desire to fly longer, I can go another minute or two depending on how I flew. Typically I fly low and slow close to me in the last minute if I go over the timer. Plus if I'm doing the extra flying, I'll see the throttle reduction from the cut off and I'll be able to land. That's plenty of time for me.

If you run those 6S 2650 packs in parallel w/ the standard ACE motor, then your gonna get similar results.

Why do you wish to run 12S instead of 6S which SOO many e550 pilots are using? From what I've played around with and read, Running packs in parallel works pretty well and less risky compared to series.

I will bet that w/ in series with the right motor Kv, ESC and pinon, your gonna get similar results. Maybe Series will get an extra 30 seconds cause you have less current draw cause of the higher voltage and thus less heating.

EDIT: based on your gallery your already doing parallel, so why the conversion? want more power (wuff wuff)?

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08-13-2009 09:54 PM  8 years agoPost 10
stocky

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Taxachusetts

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based on your gallery your already doing parallel, so why the conversion? want more power (wuff wuff)?
The whether here in MA sucks this summer, I get to fly once a week if I am lucky.

I am bored out of my mind.

I converted my 450 to 4S and love the power it gives.
I have a 6S 500 FBL that I will leave alone
I just got 6 Turnigy and 2 Zippy 2650 6S packs and thought it would be fun to go crazy with a 12S setup on my TT550
No reason for doing this apart from having some fun and having a 550 that can do warp speed.

I do as you say run the 550 on 2 parallel 6S packs, it is OK power wise but no where near Holy $hit !! power.

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08-13-2009 10:39 PM  8 years agoPost 11
Melnic

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Columbia, MD,USA

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Gotcha.
I'm betting the 12S setup will have some potential for you.
w/ the right motor/pinion I can't see it giving you less than 7 minutes. Probably more unless your hot dogging it.

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