How to add flight time

I am pretty pleased with my current flight time/duration. However, we all always want more right?

I know that minimizing weight and selecting the most efficient prop/motor combination are probably the most critical factors in determining flight time (obviously flight style/maneuver efficiency plays an important role.

That being known and me being a noob, I tried out various capacity of batteries.

4S 2200 mAH = 12 minutes

4S 5800 mAH = 23 minutes

This led me to think of a formula using the following attributes:

Max operable weight (MOW)

Thrust (prop/motor)

Total as is weight (ATW?)

I've been led to believe that a Power to Weight ration should be as follows:

1.75 | 1 [general purpose / slow maneuvering]

2.5 | 1 [agile maneuvering]

3.5 | 1 [aerial acrobatics]

So lets take a thrust value of 600 grams per motor/prop (2400) in total

Thrust / (purpose variable) = MOW

2400 / 1.75 = 1371

2400 / 2.5 = 960

2400 / 3.5 = 686

MOW - ATW = Remaining payload buffer

1371 -1000 = 371

Current lipo weight + Remaining payload buffer = Max battery size

250 +371 = 521 total weight of battery to max flight time duration.

Does this make sense / seem like a good reference model? 

Any suggestions are welcome.

Ps. are rigid props more efficient attributed to less flex? 

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Replies

  • eCalc.ch

    • I'm sure you could derive the answer using that and a few additional steps. Definitely doesn't answer the question and they have completely wrong battery weigh values.

      • The battery weights are very close.  If you need exact, then select a custom battery and make the weight what you are using.

        Note the weight listed in the selection box is the weight per cell.  Multiply by the number of cells to get the pack weight you will see listed in the specifications further down.

        • They are about 4/10ths the actual weight and the flight times are wrong by a factor of 10. I get roughly 10 times the flight time estimate.

          • I don't know what you're looking at, but the battery weights are within 5% of most commercial packs.  Make sure you are looking at the weight  line of the Battery column in the information section (not the data input section above it).

            The "Flight Time" estimate is a sub-optimal label in my opinion.  It should really be called "Max Throttle Flight Time".  Since almost nobody actually flies this way it is not really a useful number.  Most people will see their flight time as being much closer the the "Hoover Flight Time".

            • Not the zippy compact.

              0.112 (ecalc grams per mAH)

              0.088 (Zippy compact grams per mAH)

              • OK, I'll put this straight since you seem to specialize in being dense.

                You're idea is is a good one, but with eCalc it's pointless.  It is a way better tool than over simplified generalizations like you are suggesting.  If you have a component that is different than the ones listed, then just enter it's details.  It generates very reasonable numbers when given correct inputs.

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