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Old Jan 18, 2012, 06:25 PM
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And what is please the explanation for 17 amps static wot and 14 amps in flight wot? I don't get that. I checked it again and it really draws (same fully charged battery) 17 amps when static.
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Old Jan 18, 2012, 07:04 PM
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vtdiy's Avatar
Southern Vermont
Joined Feb 2007
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Amalka, the propeller unloads as airspeed increases. The closer the plane flies to the propeller's pitch speed, the less it loads the motor.The prop RPM also increases as the motor sees less load from the prop.
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Old Jan 18, 2012, 10:45 PM
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Waste heat is definitely something I have to keep in mind where I live. Case in point, it reached 70 degrees F her today (21C). In the summer it can easily hit 115F (46C) or higher. Minimizing excess heat and providing cooling airflow is absolutely critical for the health of motors, ESC's and batteries. That's why I've been looking into more efficient power combos.

I do plan to fly it with the stock power setup before buying another system. It will be flown with both sets of blades to see which gives me better performance. I can easily limit max throttle be adjusting the endpoints in my radio settings, so that's not an issue at all. One thing I absolutely do plan on is replacing the stock ESC with a higher quality, higher capacity unit. I've seen too many instances where the stock ones from HK go up in smoke with light use, much less the stress of pulling a glider to altitude on a warm day.
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Old Jan 18, 2012, 11:50 PM
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Southern Vermont
Joined Feb 2007
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Just points of possible interest, the 11x7 on 2 cells WOT is about half the waste heat of the 9x5 on 3 cells. The ESC is rated 20 amps continuous and the above combo is only drawing 12 amps through it, so there is a very good margin. I have the same ESC on an Artech spitfire with a DT750 swinging an 11x7 conventional prop on 3 cells, and have flown it last summer when it was in the nineties.

One example doesn't prove the rule, however, and a better ESC is of course not a bad thing. But weight is -- if you get a new one of higher capacity, maybe you can find something lighter.

Also, pay particular attention to the BEC rating -- should be 2 amps or better because of the loads on a sailplane surfaces.Or use a separate rcvr batt or BEC. I'd rather lose a motor than a BEC when an ESC goes.

I think a lot of ESC burnouts are the BEC section going first rather than the motor circuit. HXT900 9 gram servos draw 500 ma stalled, that's 2 amps for 4 servos, not including the receiver draw. Many ESCs have only a 1 amp rated BEC,and many rate the BEC for 2 cells and downrate for 3.
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Old Jan 25, 2012, 10:54 AM
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Had today the first possibility to fly the plane with almost no wind and scattered clouds. I could stay a loft for 45mins. I'm starting to like the plane and looking forward to fly it with some thermals, I like the way it glides.
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Old Jan 25, 2012, 02:04 PM
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Originally Posted by amalka View Post
Had today the first possibility to fly the plane with almost no wind and scattered clouds. I could stay a loft for 45mins. I'm starting to like the plane and looking forward to fly it with some thermals, I like the way it glides.
wow 45 mins is a long time, how hard did you find it to concentrate for that long? My longest on this plane is 33 mins but was not at all difficult to concentrate, my asw28 takes a bit more concentration to fly it and after about 35 mins I start to struggle a little bit.
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Old Jan 25, 2012, 03:00 PM
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Jackson Stone's Avatar
USA, CO, Parker
Joined Dec 2009
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Originally Posted by nigelsheffield View Post
wow 45 mins is a long time, how hard did you find it to concentrate for that long? My longest on this plane is 33 mins but was not at all difficult to concentrate, my asw28 takes a bit more concentration to fly it and after about 35 mins I start to struggle a little bit.
I have not had the opportunity to fly the Minimoa in lift yet, so my flights are limited by battery capacity. I typically get about 15 minutes per flight on a 2200 mAh 3 cell. I am looking forward to longer flights once we get the Spring thermal season going. I know what you mean about getting tired after a long period of concentrating on flying.

I am excited to report that I have ordered from Hobby King their 2.3 meter EPO Ventus glider. I think this will be an excellent complement to the Minimoa for the upcoming soaring season, much like your ASW28 is for you.

Best regards from Colorado, Jackson
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Old Jan 25, 2012, 04:19 PM
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Well I do have 2650mAh 3S in the nose and consumed +-2500mAh. I'm not sure if I had some lifts, but there were places where the plane just flew horizontally without loosing any altitude. Actually I was happy that the battery is finally empty as there was 2deg C and I was quite frozen...

With no wind the plane flies like on the rails. I had one hand in my pocket almost all the time. Was really very enjoyable, there is nothing much to be worried about when you just glide high in the sky.
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Old Jan 26, 2012, 11:05 AM
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Well I do have 2650mAh 3S in the nose and consumed +-2500mAh. I'm not sure if I had some lifts, but there were places where the plane just flew horizontally without loosing any altitude. Actually I was happy that the battery is finally empty as there was 2deg C and I was quite frozen...

With no wind the plane flies like on the rails. I had one hand in my pocket almost all the time. Was really very enjoyable, there is nothing much to be worried about when you just glide high in the sky.
In case you don't know using that much capacity will seriously shorten you battery life, it's ok now and then but if u do it on a regular basis you wont get many flights b4 yr batt will be nakered!
better to use about 60% or even 50% landing with 3.8v per cell and lipos will last a lot longer, but I'm sure you already know!
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Old Jan 26, 2012, 11:16 AM
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Originally Posted by Jackson Stone View Post
I have not had the opportunity to fly the Minimoa in lift yet, so my flights are limited by battery capacity. I typically get about 15 minutes per flight on a 2200 mAh 3 cell. I am looking forward to longer flights once we get the Spring thermal season going. I know what you mean about getting tired after a long period of concentrating on flying.

I am excited to report that I have ordered from Hobby King their 2.3 meter EPO Ventus glider. I think this will be an excellent complement to the Minimoa for the upcoming soaring season, much like your ASW28 is for you.

Best regards from Colorado, Jackson
The ventus looks really nice and very light for a 2.3m wingspan so should thermal on less lift then minimoa, did you get the kit or plug and fly? Seems to have poor reviews but that may just mean you need to do a few mods or change servos.
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Old Jan 27, 2012, 08:53 AM
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In case you don't know using that much capacity will seriously shorten you battery life, it's ok now and then but if u do it on a regular basis you wont get many flights b4 yr batt will be nakered!
better to use about 60% or even 50% landing with 3.8v per cell and lipos will last a lot longer, but I'm sure you already know!
I fly with the basic cell telemetry from HK (QUANTUM) and I land when the single cell voltage touches 3.3V. Who cares about batteries when the price of 2200mAh 3S 20C is 8 USD...
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Old Jan 27, 2012, 02:45 PM
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I fly with the basic cell telemetry from HK (QUANTUM) and I land when the single cell voltage touches 3.3V. Who cares about batteries when the price of 2200mAh 3S 20C is 8 USD...
yeah batts are a lot cheaper now and better then they used to be, it will be interesting to see how many flights you get out of them using them like that to see how they cope.
I know this is not really the right forum to talk about batteries but do you treat all your batts like that and have you had any problems.
In the past I flew down to lvc all time and probably got about 20 to 30 flights max b4 batts were worn out in a couple of months. Then I started stopping at 3.8v per cell which used 50 to 60% and batts lasted between 1 and 2 years depending on quality of battery.
I now prefer lifepo4 a123 batts which seem to last forever, can be drained right down, charged in 10 mins, left charged on shelf for as long as you want and still hold full charge and are physically strong too, my first set are still going strong after well over 500 cycles and 2 years of abuse still have 80% of original capacity, o and no risk of them catching fire either.
I have lots of dead lipos which not only cost money but also have to be disposed of carefully.
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Old Jan 27, 2012, 03:09 PM
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Originally Posted by amalka View Post
I fly with the basic cell telemetry from HK (QUANTUM) and I land when the single cell voltage touches 3.3V. Who cares about batteries when the price of 2200mAh 3S 20C is 8 USD...
I like the idea of telemetry but the main thing I would want is a altitude sensor with a vario with audible beeps to indicate climb/decent rate and voice reading out the altitude, now that would be really useful but at the moment that sort of tech is expensive, I really hope that the likes of spektrum and frsky take this on board and produce a nice cheap setup, they'd sell like hotcakes.
I hope this year telemetry mixed with fpv will really take off, there seems to be lots of systems about but they seem too expensive and complicated to get a fully working set up, whats needed is a one stop solution build it all in one small unit which we just stick on plane and connect our flight battery and bind to a display.
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Old Jan 28, 2012, 04:17 AM
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Originally Posted by nigelsheffield View Post
I like the idea of telemetry but the main thing I would want is a altitude sensor with a vario with audible beeps to indicate climb/decent rate and voice reading out the altitude, now that would be really useful but at the moment that sort of tech is expensive, I really hope that the likes of spektrum and frsky take this on board and produce a nice cheap setup, they'd sell like hotcakes.
I hope this year telemetry mixed with fpv will really take off, there seems to be lots of systems about but they seem too expensive and complicated to get a fully working set up, whats needed is a one stop solution build it all in one small unit which we just stick on plane and connect our flight battery and bind to a display.
My words. I'm very happy with the Quantum cell telemetry. Very easy, lightweight and cheap. No glitches, just plug it in and that is. Had it have a simple altimeter and/or vario, I paid a doubled price gladly.

However I don't like the big and heavy inline current / temp sensor. The good thing is, that you don't need to carry it all the time, but when you need only.
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Old Jan 28, 2012, 01:38 PM
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My words. I'm very happy with the Quantum cell telemetry. Very easy, lightweight and cheap. No glitches, just plug it in and that is. Had it have a simple altimeter and/or vario, I paid a doubled price gladly.

However I don't like the big and heavy inline current / temp sensor. The good thing is, that you don't need to carry it all the time, but when you need only.
http://www.hobbyking.com/hobbyking/s...mp_mAh_V2.html
is this the one you have
I have spektrum rc gear though and I see that some people have crashed due to interferance.
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