Dwayne,

This will depend on the amp draw, my guess is this prop/motor will draw around 26-28 amps static. Using the max draw down of 80% would take 1800 mah out and give a run time of just under 5 minutes which will be close on being able to complete the pattern. You can either reduce the static amps of around 20 (reduce prop size) to get about 5m 30s, or increase the pack capacity to 3300 mah.


Best,      DennisT

thats the aim - use the smallest pack possible to give you one flight.

weight is what you dont want  and bigger packs weigh more

5 minutes is not "quite" enough to get through the pattern comfortabley - i'd err on a slightly bigger pack

Thanks Dennis, so does this mean that even with a 3300 ma battery I'm only going to get 1 or 2 flights per charge?

Dwayne, it depends on the size pack and what rate you can charge it at.  my 4000mAh packs are 2C and take 45 minutes to charge.

I have 8 packs - so I can fly all day no problem - you can get away with 3-4 pakcs if you are flying with a lot of other people as you get time to charge them in between flights.

Hi Dwayne,
As you can tell already, one very short question starts a chain of "ifs" and "thens" and a whole bunch of them are necessary to say how long you can fly on a certain sized battery.

In general, though, you do not want to be flying multiple flights on a battery, unless they are quite short.
The batteries degrade terribly if you discharge them too deeply.
One discharge to "dead" turns them to trash, and a handful of discharges to "nearly dead" will shorten their cycle life dramatically.
On the other hand, if you never use the bottom 25% of charge and provide cooling so that they never see temperatures over 140 Fahrenheit (preferably not over 125F) then they will last one or two hundred cycles.

When folks say "plug and play"  that usually means ... plug a freshly charged battery in before each flight!

I hope we helped.
What is the plane, size, weight ... you know: MORE INPUT!
take care,
   Dean P.

Hi Dean thanks for the input
As stated above I have a Scorpion 3026/890 kv it's in a vector, a Future ESC and will have a Ken Doherty timer, wieghs 40 oz so with battery it should be around 52 oz.

Check out the "List Your Setup" thread for similar models.
Or read this thread: http://stunthanger.com/smf/index.php?topic=19275.0, which comes to a whole bunch of different ways of saying two things:

First, how do design your setup:

• Choose a motor and battery current capability that will deliver a maximum of 200-300 watts/pound (Rudy Taube says 175-200, but others say more).
• To go with that, choose a battery capacity that will deliver an average of 150 watts/pound for six minutes.
• Choose a Kv and cell-count combination that'll let you turn about 8000 RPM at 75-80% throttle with fully charged batteries.  For your motor you won't quite get there with three cells; four will give you plenty of overhead.

Second, how to get someone else to design your setup: take the all up weight you expect (52 ounces in your case), and see if your motor manufacturer lists the stuff necessary for 3D RC.  If they do -- use it, or the equivalent parts.

the 3026 is a pretty big motor for a vector 40 - you can use the 3020 and save yourself some weight and still have HEAPS of power

I run the 3026 in my T-rex (and Legacy) they are 60" !!!

Hi  Wynn I chose the 3026 becouse I have plans for a Time Machine 60 I'm calling the E-Machine, I have an idea on how to build it much lighter than stock so the Vector is for proof of concept and to teach me how to set up one of these lectric thingies...

Hi Dwayne,

I have run many .40 size power packages, and my favourite motor is the Arrowind/E-Max 2820 with a 40 amp esc. The battery is a 4-cell 2200 mAh Lipo. For a 5:30 flight my 43 oz. Protron uses around 1400 mAh up at our high altitude and around 1800 mAh at sea level. The prop is the standard APC 11 x 5,5 E, and I use my own governor timer system to keep the rpm constant. The motor runs so cool that I sometimes think that I should use a bigger prop, but it just works so well as it is. There's nothing wrong with "cool!"

The battery use is dependant on how you set up your flight. It only takes 5 minutes or less to complete the full pattern when you fly at a constant rpm, so the level laps go faster. At a constant rpm, like when you use a governor system, then you tend to use a steady predictable amount of power. As the others have stated, you need to use a battery pack that gives you one good flight with an edge to keep the battery happy as well. These days the Lipos can be charged a lot faster, but then you need a more potent charger that can supply many more watts. The standard ~40 minute charge is fine if you have a few batteries, and prices are pretty good right now..........and will get better still!

Keith R