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Old Jul 25, 2012, 01:21 PM
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Fantastic thermals this morning. I even managed to out climb a couple vultures I shared a thermal with on my last flight.
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Old Jul 26, 2012, 05:12 PM
Trex 700, Gaui X5, 450DFC
SoarWest's Avatar
United States, AZ, Queen Creek
Joined Apr 2010
326 Posts
Peter,
I see 2 different 9.5x8 prop/spinner combos at HK which are you using?
#1:
http://www.hobbyking.com/hobbyking/s...idproduct=5329
#2:
http://www.hobbyking.com/hobbyking/s...dproduct=13172
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Old Jul 26, 2012, 06:01 PM
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I'm using the second one, SW, but with the spinner from this 10X6 combo. I think the 10X6 would probably work well too but I haven't seen any reason to try it yet. I would guess a little slower top speed with maybe a slight increase in low speed thrust. Probably not enough difference to matter much.

http://www.hobbyking.com/hobbyking/s...dProduct=13173
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Old Jul 26, 2012, 06:10 PM
Trex 700, Gaui X5, 450DFC
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United States, AZ, Queen Creek
Joined Apr 2010
326 Posts
Have you tried measuring the load that the prop/motor combo puts out? I'm curious how many amps and watts you are actually pulling? It seems like a 30A ESC would work for you, and possibly lighten things a few more grams. Not that you have to worry, but I have a 30A ESC here and would need to order a 40A.
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Old Jul 26, 2012, 06:27 PM
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I'm still waiting on my meter which is on a very slow boat from China. But, from what others have posted about the A22-20, I'm pretty sure that I'm nowhere near the limits of the motor or ESC. It would get a little warm before I added the scoops and exit hole but now it's as cool as the ambient air when I bring it down. I was still thinking I would get a 6 servo glider when I ordered the ESC so I went to the 40A because it has a 4A BEC. Plus, not having a lot of experience with modern power systems, I figure it's a good place to exercise a little overkill. I'm pretty sure that a decent 30A ESC would be sufficient unless one went to an 11" prop and even then it sounds like people are pulling 24 A. I have yet to run the motor for more than 15-20 seconds.
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Old Jul 28, 2012, 01:54 AM
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I have to recalculate my battery usage. I flew 27 minutes with 2 climbs and came down with 11.45 volts in my battery.
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Old Jul 28, 2012, 12:30 PM
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11.45V = about 46% left in the pack, 26% usable (20% remaining) Good for one more climb?
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Old Jul 28, 2012, 01:30 PM
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I think I could manage a bit more than a single climb but was thinking more along the lines of soaring time. It will be nice when that aforementioned slow boat gets here with my watt/amp meter.
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Old Jul 28, 2012, 08:09 PM
Space Coast USA
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??
2 climbs takes ~50%, so 3 climbs = ~75% of battery capacity.

Soaring time depends on finding thermals.

I guess I've missed what you are looking for.
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Old Jul 28, 2012, 08:54 PM
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Um? Not quite. I'm still waiting on that meter so I'm guesstimating the draw on the battery at any given point in a flight. I am spending just a few seconds climbing so I have managed 5-6 climbs plus 15 minutes of aerobatic gliding and that gets my battery down around 11.4 also. What I'm getting at is that the overall draw of the motor and radio is less than I had guesstimated so, with only 2-3 climbs, I can soar longer than my previously imposed 25 minutes, give or take a lap of the field.

For an optimum flight of one 10 second climb into a boomer I figure I could go closer to 45 minutes without getting anywhere near a depleted battery. That's longer than I like to stare at the sky in one flight anyway so, basically, if I'm not using the motor I can fly as long as I want.
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Old Jul 28, 2012, 10:03 PM
Trex 700, Gaui X5, 450DFC
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United States, AZ, Queen Creek
Joined Apr 2010
326 Posts
I keep 2 timers on my radio. 1 is a down timer, where I give myself a max of 5 minutes of runtime. The other is an up timer where I track how long I've been flying. I figure with 5 minutes of engine time I can easily get 20 minutes of flying. So far when I land with a 20 minute flight after 4 min of engine time I'm at about 1/2 on my batteries. I could thus safely fly for 30+ minutes.
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Old Jul 28, 2012, 11:14 PM
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That's what I do too, SW. I just keep adding to my total limit as I learn the Specter's power consumption.
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Old Jul 29, 2012, 12:42 AM
Trex 700, Gaui X5, 450DFC
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United States, AZ, Queen Creek
Joined Apr 2010
326 Posts
Do you feel this smaller motor might work just fine in the Specter? I don't need to be vertical and a few more seconds to get up might be more than made up in lighter weight when thermalling? With this motor I could also go with a 30A ESC?

http://www.hobbyking.com/hobbyking/s...ner_Motor.html
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Old Jul 29, 2012, 12:57 AM
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I think that one would work great, SW. As much as I enjoy having an overabundance of power one could get along with a whole lot less. This was actually my first choice and I still might pick one up. I don't see why it wouldn't work with a 30A ESC and might have even better performance than mine.

http://www.hobbyking.com/hobbyking/s...er_1250KV.html
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Old Jul 29, 2012, 01:05 AM
Trex 700, Gaui X5, 450DFC
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United States, AZ, Queen Creek
Joined Apr 2010
326 Posts
That looks like a nice engine. One advantage is that you would not have to turn the shaft around, it already comes mounted the way you needed it (compared to the engine I previously noted, the one you are using came setup oriented correctly). Of course it's much higher in price by still so much less than picking one up from LHS.

How hands off does the Specter fly? I don't see much dihedral in the wings and wondered how it self levels. It would matter mainly if you wanted to be able to really go high and do some hands off flying and trust it remains level.

I fly my gliders with an A9 so I was looking at setting it up to monitor the main battery power instead of just what the ESC sends to the radio through the SPC port as another way to watch my power through the flight.
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Last edited by SoarWest; Jul 29, 2012 at 01:24 AM.
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