Now I can time (approximately) flights of a South Carolina Arducopter

 

It took me a little while to learn what most of the switches and buttons on my DX6i could do. This past weekend the Trainer switch was assigned to start the timer in a count up mode.

Behold!

With my EFlite 30C 11.1V 3200 mAh battery almost 7 minutes of mostly hovering flight was achieved (no touch down at all until exhausted).

"Is that all you get?" comes the question from the group.

To that end one issue has been my conservative approach to charging the battery. Keeping a battery cycle log seemed like a good idea and there the evidence can be seen that although a few balancing charges have been made, the charge rate needs to increase. The cell values of the charge prior to this flight were: 3.96, 3.97, 3.97. The first couple of cycles saw 4.2V nominal. I seem to remember dropping the charge current to 800 mA. The heli buff at my LHS keeps his cells at the 4.2V level.

I think this battery can handle more, don't you?

Oh, did I tell everyone on the 3DR and APM hard/software teams how happy I am with the way this copter flies?

WOW! It flies like it has rails and I haven't even adjusted any of the PID settings or any other variables, just TX trim. Many times I have simply held the TX in my right hand and enjoyed watching her sit in the air. Hi-5 to all the devs. Why anyone would want another autopilot is beyond me.

So, if you read this, and you have some data, why not respond with your flight times. Once the battery is topping off better, I am sure the time will be closer to 8 minutes. Cutting weight would help on this bird but.. I won't complain about her weight if she doesn't complain about my flying. ;)

Of course if you have two batteries, half my weight (now at 3.4 lbs/1.5 kg with battery), then you will stay in the air longer.

This build is a trainer/development platform. The next build may be also based on the 3DR frame but the goal will be to cut frame weight to allow 2 batteries.

I've got the multicopter monkey on my back now...and I love it.

Views: 669

Comment by Luke Olson on September 7, 2012 at 6:07am

The flight time sounds like its in the ballpark. If you want to run the numbers this is useful calculator.

http://www.ecalc.ch/xcoptercalc_e.htm

I just tried it out on my setup a few days ago. It shows a hover time of 20.25 minutes, hopefully I can test that this weekend.

Comment by R. D. Starwalt on September 7, 2012 at 8:54am

Luke, thank you for the link.. and you are correct about me being in the ball park.

With better numbers regarding the parts (a sure thing to obtain for the next build), this is a great tool for modeling the model!

I think that stating the xCopter Weight 'incl. Drive' implies total system weight with battery. As previously stated, one of the next build goals is to cut weight.

Weight is the enemy of things that move.

Comment by R. D. Starwalt on September 7, 2012 at 6:00pm

A post blog-post flight update: I charged at a higher rate, 1.6A (the battery can handle 3.2A) and packed the 3S full. It had sooo much more authority that I had trouble with the liftoff, being accustomed to the previous throttle settings. So much trouble that I was overcorrecting and ended up with the quad behind me quicker than I was ready for. A few chopped up tree leaves and other dodging put me close to my carport. To prevent collision with the wife's car I sat it down hard. One leg side broke at 'the toe'  but all else was fine.

With my planned hover test data gathering wrecked the consolation was having the video cam running so the thrashing flight was recorded!

The next hop up saw me using less throttle to get the same results. Muscle memory can be a problem when running under less power than the system can provide.

A couple middle school boys in the neighborhood were attracted to the show. So much for data gathering, time to do outreach again. With their questions answered, up she went for a more controlled flight. Slow yaw rolls left and right to capture some scenery on the cam resulted in the previously reported tendency for the bird to lose altitude after a complete circuit (I have run in nothing but Stabilized Mode so far). This is most likely due to the 'thumb method' of operation while holding the TX. Making a perpendicular movement while holding throttle is against thumb geometry so I suspect this contributes to the noticed affect.

My oldest son's girlfriend had arrived about the time the battery was showing signs of fatigue so I yaw rolled to face me and sat the quad down in the uphill neighbor's yard.

This is a screen cap of the MP4 file. Not counting the early bang up, the video is about 8 minutes long so.. this would imply a hover time well within the estimate from xcopterCalc.

 

Comment by Carl La France on September 8, 2012 at 12:26pm

Excellent R.D. Good to see you are having Fun with your Flying Machine! There are smiles on every one ! Have a great Day !

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