Questions re: Swift 16 for scale [Archive]

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Rodan

08-20-2007, 10:52 PM

warpspeed

08-20-2007, 11:57 PM

I'm no expert and have only had my 550 for a couple of weeks, so take this with a grain of salt. I don't know about the A123 cells, but I'm running a 4s 4650 TP and with nothing more than just FFF that baby comes down pretty hot, and it looks like the max I can get without going beyond 80% is roughly 6 minutes. Like you I was looking for max runtime without having to pay the 6s price, but unfortunately that may be the magic ticket. I've been running 600+, 13t pinion, and 520 woodies. Motor does fine on 4s, speedo doesn't even get warm. Haven't tached it yet, (tach just got here today) but online calc's estimate headspeed near 1900rpm. Based on that with the gearing you have in mind 8 minutes should be attainable-but that probably depends on how much extra weight the body adds.

Greybird

08-21-2007, 06:42 AM

Warpspeed, Have you tries a smaller pinion? An 11 tooth give 1750 or so headspeed.on that set-up. For no 3D, you could use less rpm. Things will run cooler, and flight times will go up.

Gudmund

08-21-2007, 10:26 AM

I am wrestling with the same issues. My brand new Swift uses the 600+ motor and I have a 4000 mAh 4S1P lipo. The heli-motor-battery combo, unfortunately, came with a 9-tooth pinion which only produced a max headspeed of 1400 rpm. I have now acquired an 11-tooth and a 13-tooth pinion. The former gives a headspeed of 1700 and the latter is in the 1900 range.

A fellow flyer, also with a Swift, 600+, and 4S1P setup uses a 12-tooth pinion and has a headspeed of over 2000 rpm. The differences between the two setups are that he uses expensive CF blades, while I am spinning the Century wooden 520s, and I use soft-start and governor while he does not.

Do the blades make that much of a difference?

Can I realise more rpm by switching to regular-start and non-governor mode?

Gudmund

warpspeed

08-21-2007, 10:40 AM

Warpspeed, Have you tries a smaller pinion? An 11 tooth give 1750 or so headspeed.on that set-up. For no 3D, you could use less rpm. Things will run cooler, and flight times will go up.

Exactly what I was thinking. I need to order parts anyway so I'll pick up a couple of pinions while I'm at it. Is 1700-ish headspeed enough? (for scale-like flight)

For that matter Gudmund, how does your's fly at that headspeed? Do you experience any bobbing or other strange behavior? I'm at high altitude so I don't know if I could get away with a 9t or not-but in the pursuit of runtime I'm willing to try anything!

Gudmund

08-21-2007, 10:55 AM

Warpspeed - At 1400, it was a bit of a dog, but at 1700 it flys quite nicely (my abilities are non-3D only). I want to try the 13-tooth, 1900 headspeed as I may be able to use that pinion with the throttle curve set at 80-90% - I am shooting for headspeed of 1800.

Gudmund

Rodan

08-21-2007, 12:39 PM

Thanks for the replies!

It looks like I can get where I want to be with the 600+ and probably a 10T or 11T pinion. Hopefully I'll be moving forward with this project soon....

Gudmund

08-21-2007, 05:14 PM

In an attempt to see what differences, if any, the various settings on the Century 55/70A ESC would produce, I tied my Swift to a table, set the pitch curve to 50,50,50, added a Watt meter to the circuit and did some tests. (Motor 600+, 13-tooth pinion and wooden 520 blades) The following data was recorded:

Mode 1 - soft start, no governor
Voltage 14.4, amperage 26.4, headspeed 2100
At 80% throttle
Voltage 14.6, amperage 18.3, headspeed 1800

Mode 2 - soft start, governor
Voltage 14.5, amperage 23.9, headspeed 2000
At 80% throttle
Voltage 14.5, amperage 17.9, headspeed 1800

Mode 3 - regular start, no governor
Voltage 14.4, amperage 25.5, headspeed 2100
At 80% throttle
Voltage 14.5, amperage 17.2, headspeed 1800

Now there is very little scientific about this test, but it appears that Mode 3 gives the desired 1800 rpm headspeed with the lowest power draw.

The other, less definitive, advantage to the Mode 3 seems to be a better start-up. In both soft start Modes, the motor had a tendency to stutter as it was beginning to spool up. With the regular start Mode 3, this tendency was absent.

I would now love to make a few blade swaps and do the same measurements. I am sure that the better (more expensive) blades will give an even higher headspeed with lower power demands. But that will need to wait a while.

Gudmund

JustPlaneChris

08-22-2007, 03:11 PM

I'm in the researching stage of building an Approach e-Cobra scaler using Swift 16 mechanics, and have some questions for you Swift experts out there...

I'd like to use A123 cells in a 5s2p configuration, which should be roughly equivalent to a 4s 4000mah lipo pack, and I'm looking for a headspeed around 1600-1700 max. I'd like to use 550 main blades to be more proportional to the scale of the fuselage. Obviously, scale flight is the goal, so no 3D, and I need to get around 8 minutes duration.

So, the questions:

1. Is it possible to get 8 minutes out of a 4S 4000 setup at 1600-1700 headspeed with 550 mains?

2. What motor/pinion combo should I be looking at for greatest efficiency on 4S? I've done some searching, and it looks like the 600+ will get me there with a 10-11T pinion, but I'm wondering how efficient it will be on 4S. Is there a better choice?

Thanks!

Rodan, I just got my Swift flying with 10S1P A123. I'm using a Neu 1910/1.5Y, and based on others results I think something like that (or the Z30A-800) would achieve your goal. I'll know more after this weekend, when I will take it to the big flying field for a proper shakedown, but so far it looks like 6 minutes is easy to get even with headspeed in the 2000 rpm range! I have now dropped to a 9T pinion, as I too want lower headspeed for scale / sport flight. (Love that Cobra body!!) My only concern about using A123 in the Approach fuselage is fitting the batteries.

Anyway, I am convinced that high voltage/low amperage is the way to go on these bigger helis. If you are going to carry 10 A123 cells around, you may as well crank the current so everything runs cooler. :cool:

-Chris

Rodan

08-22-2007, 04:29 PM

JustPlaneChris

08-22-2007, 04:50 PM

Wow, you're getting 6 minutes on a 10S1P A123 at 2000 headspeed? I had thought about higher voltage setups for the obvious advantages, but thought I would need to run 2P to get anywhere with the low mah of the A123s... now you've got me thinking...

'Course, the disadvantage is more expensive motors and ESCs....Well, to be honest, I'm not getting that, since I've not yet "flown" my Swift, just hovered it around the yard. :o Prior to choosing my power system, I got advice from gents who have used that setup, and that is what they report. Here's a snippet of one of our conversations when discussing my Neu motor setup:

If you still want to go scale, you could swap to a 9t pinion, which would lower the HS to around 1950 at 100% throttle, this would give you some nice room to dial back the governor for a HS around 1750-1800, perfect for scale. Your flights would be at least 7min, probably longer. Otherwise The Z30-800 is an option, it would need a 9t pinion and have the gov turned down to get a lower headspeed for scale flight, but the 9t would really be your only choice.

Based on my trim flight yesterday, it seems to be accurate. I was hopping up and down, adjusting curves, gyro, tracking, etc. for at least 5-6 minutes and only used 80% of the pack capacity.

The Z30A-800 motor isn't much more expensive than the Century 600+, so your only additional expense is for a high voltage ESC. I'm using a Castle Phoenix 45HV, which is still fairly reasonably priced.

The thing to remember is that it's going to take a certain amount of power (watts) to fly the heli, regardless of your choice of motor or battery. The decision is how you want to obtain those watts: High volts and low amps, or low volts and high amps? All else being equal, high voltage is going to be more efficient every time.

-Chris

Greybird

08-22-2007, 09:05 PM

Dang, Look at my Swift packs. Am I the only one that likes long flights?

Neogenesis

08-23-2007, 12:12 PM

Just food for thought here. Keep in mind I'm new to heli's....espically the electric crowd...but thought I would post my setup and flight times.

Lightning 600 "not plus"
6s1p 4000 mah packs 15C
Electron 55/70 ESC
I'll have to check what pinon...can't remember right now.

I'm working on hovering is attitudes....and am pulling 10 min flight times with CF blades. I'm putting about 75% of the pack back in when charging. The best part is the 15C packs are so much cheaper that anything else out there. $110.

Neo

Rodan

08-23-2007, 12:41 PM

What brand packs?

Also, do you know what headspeed you're running? Also, what size blades?

Greybird

08-23-2007, 06:04 PM

Maxamps. 1750 head speed.Stock wooodies. The 2s 8000 packs go for 15 minutes. The 10,000 pack flys for20 minutes.

aramsdell

08-23-2007, 06:31 PM

More expensive blades..... I tried them. Now I have to have them. I have been flying mine on 5S4000 and 10 T pinion with 550 Rotortech's($90). Short flights. I was going to drop to 9T to get just a little more time out of it.( I've been getting 3 min of hard 3D) now I have just test flown it for a couple of minutes on a new 6S 4000. Still had the 10T on. Holy batcrap! The headspeed was insane and it flipped like my TREX 450 at 3000 rpm. REMEMBER Century has an 8T pinion for 5mm shafts. It's in the Swift parts area. I think I'm going to drop all the way down to that for a while and see if I get a cross between duration and more fun than I was having with 5S and 10T.
If you want a lot of fun on a light machine go for the 515 Rotortechs,600+ 11 to 12t pinion for 5S and 12 or 13 for 4S. Watch your times.

Greybird

08-24-2007, 07:42 AM

Hmm... If you are pushing an electric that hard to drain the batteries in 3 minutes, maybe you should consider a nitro Raptor or something.

Rodan

08-24-2007, 08:44 AM

Actually, my question was for Neogenesis, I'm wondering where he's finding 6s4000 15C packs for $115??

JustPlaneChris

08-24-2007, 09:23 AM

Possibly TrueRC packs? http://home.comcast.net/~truerc/ready_pack/ready_packs.htm

-Chris

JustPlaneChris

08-24-2007, 08:55 PM

More info on flight times with the 10S A123 setup:

I took the Swift to the big flying field today for its first "real flight". Not knowing what to expect for flight time, I had the timer set to 5 minutes, and went about 20 seconds over. Recharge data was 1210 mAH, which means consumption is 242 mAH/minute or 14.5A average. That means I can set the timer for 7.5 minutes to use 1800 (around 80% of the pack capacity). Even though I've been told you don't have to baby the A123 cells that way, I probably will anyway just to keep a buffer.

My face hurts from grinning so much. :D

http://www.youtube.com/watch?v=u6WUoQ8y4-4

-Chris

Rodan

08-24-2007, 09:27 PM

Looks good! So what headspeed was that? And that's the 10S1P?

JustPlaneChris

08-25-2007, 12:18 AM

Yessir, 10S1P. Headspeed calculates to 1850 (left my tach at home!), and the current draw and the way the blades appear on video supports that estimate. I don't think I'll be going to the 10t pinion anytime soon, that's plenty of power for my style of flying. AUW is 2757g, or 6 lb 1.3 oz.

-Chris

Gudmund

08-27-2007, 11:21 AM

My Swift with its 4S1P, 4000mAh, battery, stock 520 wooden blades, 600+ motor, 55/70 amp ESC and 13-tooth pinion is now giving me 8 minutes of hovering and FFF with a headspeed of about 1700. I am quite pleased with this state of affairs as the model is very well mannered and the ESC works very well in governor mode. At the end of a flight, the battery is slightly warm, the ESC about 130 degrees and the motor about 110.

Gudmund

Neogenesis

08-30-2007, 04:18 PM

Possibly TrueRC packs? http://home.comcast.net/~truerc/ready_pack/ready_packs.htm

-Chris

My apologies.......I haven't been back to check on the thread in a bit. Yes they are True RC packs.....I can't complain about them one bit. Woodies or Carbons don't seem to effect flight times.......I've never measured actual head speed........but it's fairly crisp and if I dump full cyclic....it climbs pretty well.

Neo