|
|
|
|
|
|
||
|
|
Quote:
|
|
|
Latest blog entry: SS FPV Maiden
|
||
|
|
|
|
Joined Aug 2011
1,054 Posts
|
I had a fantastic UAV flight this morning, 6.7km no problems. Even had 2 hawks join the SW at some point!
I;m just a little disappointed about range. I have 2 x 5000mAh 3S batteries and managed 6.5k dropping the batteries by 0.4V (24 minutes), which I calculate will give me ~ 30kms maximum range. I've seen people do much more with smaller packs, but maybe that's with some thermal activity. Would it help if I use 4S in stead of 3S? Should I drop the KV? Should I reduce cruise speed? I've used ecalc, but I can't really make out what to change to improve flight time See ecalc stats here. According to it, if I change my 1040KV Scorpion to a 830KV, I get almost double the flight time. I don't understand how this is possible and I'm doubting the result. Any suggestions are greatly appreciated. |
|
|
||
|
|
Quote:
|
|
|
||
|
|
||
|
|
Quote:
|
|
|
||
|
|
|
|
|
|
|
Latest blog entry: Mystery summit FPV adventures
|
|
|
|
||
|
|
Quote:
|
|
|
Latest blog entry: Transplanting a Spektrum Dx4E Rf Deck...
|
||
|
|
||
|
|
Quote:
You need to measure the amount of juice you're putting back into your packs. I did 20km in the air on a single 3S 4000mAh pack, putting 3300mAh back into it on charge. That was level flight, *slow and steady*. Averaged 6.5A draw over 30 minutes, at about 26mph. Unless you've wildly over or under propped your plane, there's no reason to expect less performance than that. My SW is pretty draggy with the GoPro out front, and flight camera perched on P&T up top. With minimal aerodynamic improvements, should be able to cruise at 5A. The main problem is going to be one of patience. People often just don't have the patience to fly slow and efficiently, and a little throttle will easily double your current draw, but it doesn't double your speed. ian |
|
|
Latest blog entry: My 2012 FPV year in Review
|
||
|
|
||
|
|
Quote:
capacity than a 3S 4000mAh pack, because it has one extra cell. Your min sink cruise current draw will be 25% lower but instantaneous wattage, and total Watt hours will be the same. There's some variation due to prop selection, motor efficiency etc, but whenever you're comparing a 3S to a 4S setup, remember the 4S battery is really 33% bigger. ian |
|
|
Latest blog entry: My 2012 FPV year in Review
|
||
|
|
||
|
|
Quote:
|
|
|
Latest blog entry: Transplanting a Spektrum Dx4E Rf Deck...
|
||
|
|
|
|
|
My point is, cruising amps and the mAh you put in on charge, are both skewed
when using a 4S pack. You can't use amperage as your measure of capacity alone. If total efficiency were exactly the same, a plane that cruises at 6A on 3S pack, will cruise at 4.5A on 4S pack. And likewise, if after a min sink level flight you re-charged a 3S 5000mAh pack with 4000mAh, you'd only put 3000mAh into a 4S 5000mAh pack. There's no gain in efficiency simply by going to 4S, you're just adding capacity by adding another cell. Could get the same increase to the 3S setup by using a pack that's 33% larger. There's nothing wrong with 4S, just be careful in thinking that you're seeing a gain in efficiency, when really all you're seeing is a gain in battery capacity. ian |
|
Latest blog entry: My 2012 FPV year in Review
|
|
|
|
||
|
Joined Jul 2011
32 Posts
|
Quote:
at least ,i dont know 100% if i can thrust my constuction and want to take the four gum-strips(dont know the word) i made some better pics....i think that should work. if its not rainy here i will make the maiden fly and try do make a video. so far. alex
|
|
|
||
|
|
||
|
USA, NV, Las Vegas
Joined Apr 2006
321 Posts
|
Quote:
Your 3014-104 with a 9x6 is to small to get good performance from the motor (less than 50% power). Its only pulling 19 amps from a motor capable of pulling 40 amps. The 9x6 produces 1084 grams of thrust with an impressive 5.42 grams of thrust per watt of power consumed. If you stuck a 10x5 on there you'd get 200 grams more of thrust with only 3 more amps giving and even better 5.6 grams of thrust per watt. If you used a 4 cell and a 9x6, you'd have gobs more thrust available, but the thrust per watt decreases. If you used a 3 cell and a 9x4.5, you'd lose even more potential thrust than you have now, but it the most efficient prop for that motor with more than 6 grams of thrust per watt. Scorpioncalc agrees that the 9x4.5 is most efficient with that motor on 3 cells. But a 10x5 is almost as efficient with lots more power available. |
|
|
||
|
| Thread Tools | |
Similar Threads
|
||||
| Thread | Thread Starter | Forum | Replies | Last Post |
| Question Best plane for FPV while on vacation? | patricklupo | Video Piloting (FPV/RPV) | 23 | Aug 08, 2010 06:27 AM |
| Cool FPV plane rescue with an FPV truck :-) | AnthonyRC | Video Piloting (FPV/RPV) | 17 | Feb 24, 2008 10:45 PM |
| For Sale Skywalker plane and a bunch of extras | moody07747 | Aircraft - Electric - Airplanes (FS/W) | 8 | Sep 19, 2006 09:34 PM |
| Discussion Aviator Skywalker RC plane given to me | moody07747 | Electric Plane Talk | 46 | Sep 12, 2006 11:45 AM |