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Endurance

Posted by Alex on June 15, 2010 at 2:42am
So i have seen that most of the military electric MAV has endurance of at least  40min-1hour!  I was wondering if there was any secret to how they achieve this or is it as simple as adding a few more lipo batteries at the sacrifice of extra payload if you plane can handle the extra weight?

Obviosuly there are other factors like the efficiency of the design, and engines etc.. but I was just wondering if the major component would be to just add more batteries?

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  • hamish November 17, 2010 at 2:05pm
    an article from the RAeS

    http://www.aerosocietychannel.com/aerospace-insight/2010/11/staying...
    http://www.aerosocietychannel.com/aerospace-insight/2010/11/staying-up-ultra-long-endurance-uavs/
    See related links to what you are looking for.
  • Stephen Wuest November 16, 2010 at 7:17pm
    Big thermal sailplanes (3-4 meters) can stay up for hours, thermalling. They may only have an 1800mAh 2S LiPo battery.
    But just staying in the air a long time, doesn't mean that the plane can complete a specific task!

    There is no universal "optimal" design. You must decide what your priorities are (including cost, range, max and min flying speed, sound and radar profile, payload, ...) before you have any a context in which to try to develop an optimal design.

    You can add some more batteries on a bigger design, but it needs to be low drag. There is a real cost limitation for the hobbyist, that the military UAV makers don't have to worry about.
  • hamish November 12, 2010 at 12:59pm
    With the right time and knowledge you can create an aircraft thats very efficient for a certain weight and speed

    it may be crap when flying off design, but when flying at the mission conditions i dont see why our consumer tech shouldn't last ages too.
  • Ronald Bryant October 23, 2010 at 5:41am
    only for planes flying in very sunny countries, with wing chord so large that edges of those panels will not disturb airflow worsening glide ratio.
    Then you must to add power management unit.
    Not worth it in most cases (worsening performance) unless you are rich, flying big (a few meters) in a specific place, or have gas-only UAV. I believe out of reach of DIY amateurs. Of course anybody can add something, a bag of nails, gummi bears, solar batteries, but getting more endurance with it is a real challenge.
    It will end with ppl arguing 'my audi officially gets 3.2l/100m, but my particular example goes down to 1.9l/100km!!! - yeah, but mine did 1.75 easily when new!' etc.
    Basically Solar plane is a very flimsy construction. It is very hard to tune such plane for autopilot without crashing it at first, if you work alone.
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  • Cronselaar September 15, 2010 at 5:42am
    Hi
    Also using a trainer tipe plane... Almost the same as a telemaster... I get 40mins of flight on 6s5000mah and a 13x6 prop..
    More than enough for me... In winds it goes down to 30mins...
  • Kim Skatun September 15, 2010 at 1:28am
    I have a simple 3.2 m glider, With this setup I have around 6 hours flight time. 12X3S lipo at 3000mah.

    I think thats a good option, to get long range and long flight time.. Basically bigger plane is better due to flight perfomance at higher speeds.
  • Andrew Van Der Plaats September 12, 2010 at 7:08am
    Look for information concerning use of 'fuel cells' in UAVs for the answer.
  • Keegan August 15, 2010 at 1:44pm
    Putting more batteries in a plane does increase range, but it also increases stall speed. My Rc high wing trainer can last 40 minutes at cruise speed. The batteries for this long of a flight weigh more than the airframe and make for very sketchy and fast landings. I think the range of a Uav depends on how fast you are willing to land it!
  • Adrian Eves June 15, 2010 at 6:52am
    It's all about getting efficient cruising flight.
    I know an electric MAV that will do 2 hours with it's normal EO mission payload using lithium batteries.

    Cropcam will fly for over an hour with a simple P+S camera, but could go longer with modification.

    Of course most UAS manufacurers feel the need to use 'sexed-up' performance data.
  • T3
    Krzysztof Bosak June 15, 2010 at 3:40am
    It is safe to assume MAV have datasheets based on unrealistic data, without payload.
    Same story with cropcam.
    I would say most of those systems really fly for 30min if you take into account their cited mission radius
    which is notoriously around 10km max.

    Second secret they can double the numbers using non-rechargable version of hydrogen cells.
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