Replies to This Discussion

Permalink Reply by Veikko Vierola on April 1, 2012 at 2:13pm

I don't know why the maximum flight time is tested in hover. At least in traditional helicopters the maximum flight time is achieved with some forward speed as you can see from the graph.

I'm not sure how directly the graph is usable with quads or hexas which have rigid rotor system.

But perhaps someone could test it by flying with different airspeeds at the same height and at the same time check how many amps is going to the engines.

-Veikko-

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Permalink Reply by Bjørn Didriksen on April 19, 2012 at 6:10am

When traveling fwd in an normal heli, you have relative wind due to the fwd movment throuh the air. The blade angle of the blade moving fwd is reduced, and the blade moving back is increased due to the decrease of relative wind speed.

Since we do not have this on quads, I would guess that this principle would be valid due to the rigid rotors we use.

But I am not 100% sure!

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JDronesPermalink Reply by Jani Hirvinen on October 10, 2010 at 9:50am

Dan, i've found few companies so far that makes similar really low low KV motors, price range is from 100 - 400 EUR each. Just like those 15" CF props. They are really expensive but then again if your quad costs 25.000+ USD who cares if you have 400 USD motors on it. Price has to come from somewhere anyways :)

That video is a bit deceiving, guys are flying inside hall where they do not have any wind to messing up hexas, no payload, no landing gears etc. Ok only payload is battery. If they would do this somewhere outside, i'd say take out 10 minutes at least from flight times with same setup.. Ok even if its 30 mins, it is still rather good. Anyways MK is rather good, so we have nice goal to catch in ArduCopter group

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Permalink Reply by Dan Sibisan on October 10, 2010 at 10:04am

I well order tows motors from MK 65€ each , and make some tests. With some 10.000 and 15.000 mah packs , and se ifs worth it .
I`m sure that Arducopter well be whey more bather then all others, is the progress keeps going this fast :)

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Permalink Reply by Brian Bills on March 5, 2012 at 11:47am

Sorry to resurrect an old thread but had a couple questions.  I'm in the process of developing a VTOL quad for extremely high endurance.

I noticed one of the posters, Maximus, had access to some really nice low KV, high torque motors.  Does anyone else know where I can go to find suitable props, motors, etc... for this task?

Many Thanks,  

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Permalink Reply by Todd Hill on March 5, 2012 at 3:46pm

RC tiger motor MT series, Hobbyking NX series motors for multirotors.  Been using the NX-4005 650kV and the MT3506 650kV for my builds with really good results.  High stator and pole count.  These motors are really quite.  You may also want to check out the 5010-14 360kV outrunner from rctimer.com.  Motors such as this will provide more torque to turn a larger high static thrust prop.  I am drawing literally half the amount of current with these motors than I was with motors that had fewer stators and magnets.  Good luck:)

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Permalink Reply by Ayush Gupta on March 5, 2012 at 8:03pm

Todd could give specifics about your setup as in :

Amount of Battery (mAh)

config (xSxP) 

Weight of Battery (gms)

Flight Time at hover (min)

Along with the motor used....

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Permalink Reply by Maximus on March 6, 2012 at 12:30am

Hello Brian,

My motors are 24 poles, nothing to do with RCTimer (12 poles) or other low quality motors

W4822

nobody knows that MD used lithium-sulfur batteries that gives 3 times flight time of Lipos....but very low number of cycles !!!

Cheers

Maximus

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Permalink Reply by Todd Hill on March 6, 2012 at 2:12am

@Ayush, the NX-4005 motors are 24 pole. And at around $30 they are worth a try. my only suggestion is change the prop nut, as the ones supplied are weak. 4S1P 5A Lipo (486g), 12*3.8 APC props, MT3506 motors, custom quad frame (1.2-1.3kg auw, without/with body), 25min flight time, and my Lipos' have seen better days. Stil testing the NX-4005 motors. so far they are looking more promising than the MT3506 motors. regards:-)

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Permalink Reply by Ayush Gupta on March 6, 2012 at 5:44am

@Todd, Thanks for info. How much flight time are you getting with the above mentioned 4S 5Ah battery ??

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Permalink Reply by Brian Bills on March 6, 2012 at 8:21am

Thanks for your reply guys.  I have several days of hands on experience with the MD4-1000 and with 6s lipo batteries and a standard point and shoot camera we were getting around 40 minutes of usable flight time.  There is just no way MD can claim that amount of flight time with the same setup.  They have to be using primary batteries as Maximus suggested.  @Maximus can you confirm this?

I've been looking into the rctimer 5010 motor and I've noticed a few have compained about quality but it looks exactly like the motor I need for the job.  I's like to try Maximus' motors but they are very heavy and not sure how they would do with much bigger props.

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Permalink Reply by Todd Hill on March 6, 2012 at 8:49am

@ Brian, rctimer will do custom stator wrapping to match the kV you need, or if you have a little experience you can re-wrap them yourself.  I usually replace the bearings on all of the budget motors I buy, as they are generally weak. You may also want to check AHM brushless motors, but they are pricey.  They also sell the parts to build motors yourself for a lot less.  Just giving you some options.  

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