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Old Oct 18, 2014, 01:33 PM
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United States, SC, North Augusta
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2.5M Spider power set up

I'm fairly new to powered gliders and just purchased a 2.5M Spider basically BNF advertised in the classifieds here a few weeks back. Did the maiden today and am looking for advice with the power system I'm running.

It is powered by a Hacker B50 9S 4100kV, 6.7:1 gearbox, swinging a RFM 17x13 prop, Jeti Tx and ESC (Mezon 90 lite) for telemetry. Battery: TP 2700 4S 70C

I did about 5 full power pulls of about 5 seconds and recorded this through my Jeti tx(these numbers were observed while doing full power climb outs:

Amps recorded during each pull= 88 (although the specs on motor list max amps as 80A at 15 seconds and max power of 900 Watts.

Battery voltage under full power = 14.2 volts
maH consumed during each pull = 140-180 mah

RFM 17x13 Prop RPM = 5780 (static)

Weight: 1911 g. / 67.4 oz (without battery) 2211g/78 oz with 4S 2700 battery installed (RTF)

ESC temperatures: (ambient=70F/21C) at the end of my flight I was at 122F/50C
I did not record motor temperature but did place a finger on end of motor at end of flight and had no issue with holding my finger there for as long as I wanted. Will use IR gun next time out

Watts: If I'm doing the math right, I'm seeing about 1250 watts (14.2 volts x 88 amps)

I would appreciate if you more experienced pilots could look over my numbers and provide any input before I continue flying.

I'm a bit puzzled at how a motor with a 900 watt power output by manufacturer shows 1250 watts.

Same concern with motor amps under load. Do I need to be concerned with my 88A recordings with the spec listed as 80A max on the motor?
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Old Oct 18, 2014, 05:02 PM
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Greeley, Colorado, USA
Joined Feb 2000
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John,

Shouldn't be any problem for the motor. I ran that motor in a bit larger model for a while at about 2200W on 5S.
I have no idea about your ESC though.

Good luck,
Lenny
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Old Oct 18, 2014, 10:31 PM
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United States, SC, North Augusta
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Lenny,

Thanks for looking over my setup. The Jeti Mezon 90 lists continuous amps at 90 and max amps as 300. So, I assume I'm OK.

John
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Old Oct 19, 2014, 01:21 AM
The Sequel
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Australia, VIC
Joined Sep 2011
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which prop are you using, if prop rpm is 5780, then motor is 38726, so well within, as Lenny says 5s would be fine, loaded properly, these are in air numbers?
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Old Oct 19, 2014, 07:38 AM
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Quote:
Originally Posted by mustflynow2 View Post
which prop are you using, if prop rpm is 5780, then motor is 38726, so well within, as Lenny says 5s would be fine, loaded properly, these are in air numbers?
I updated my post to include prop used during my maiden (RFM 17x13). The yoke installed does have offset, no twist.

Yes, all the data was recorded while in flight.

I happen to have the same prop in a 16x13 size. May give that a try and see what happens.

Having a desire to go fast, I have a feeling a 5S pack will find its way into the fuse in a month or so : ) If necessary, I have a Mezon 130 ESC I can pull from a heli if I'm pushing the 90 lite installed now.

Thanks for all of your input guys. I'm going to take this project a little slower than the last. There is so much to learn. Last month I crashed a Hornet while experimenting with prop sizes. I was so focused on exceeding amps, dipping battery voltage, high esc temps and in a effort to correct these conditions, I started reducing prop sizes. Eventually, I got down to a 16x10 and was over revving that prop by 400 rpm (according to specs provided by manufacturer, which I failed to read). On my 4th pull, one blade failed near hub. The short but violent vibration ripped one aileron from wing, hatch flew off, followed by battery. I was a spectator at that point.....spiraled in and snapped fuse in half. Funny, I had the prop rpm displayed live on my Tx screen at all times. Just never gave it any consideration. Live and learn.
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Old Oct 20, 2014, 09:39 PM
The Sequel
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Australia, VIC
Joined Sep 2011
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Hi john, I was just wondering, can your jeti gear produce a 2d graph of your flights? Would be interested to see
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Old Oct 21, 2014, 05:26 AM
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United States, SC, North Augusta
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Telemetry

Yes, I can view (from tx screen) during or after a flight. In this example, it is clear the battery I purchased with the Spider was junk.
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Old Oct 21, 2014, 05:36 AM
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United States, SC, North Augusta
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With a better battery. I can plug Tx into a laptop and view as many points of data at one time. There is also another hand held device (about the size of a thick cell phone) that displays the data live. I have a helper use this to view data while I'm flying so he does not have to look at screen on my tx.
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Old Oct 21, 2014, 03:40 PM
The Sequel
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Australia, VIC
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Nice stuff, so a log post flight with all data is possible
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Old Oct 21, 2014, 04:36 PM
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Quote:
Originally Posted by mustflynow2 View Post
Nice stuff, so a log post flight with all data is possible
Yes
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Old Oct 21, 2014, 04:48 PM
The Sequel
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Australia, VIC
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Ok cool, do you have an example of your flight, easiest way to see what's happening
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Old Oct 22, 2014, 11:19 PM
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Brazil, MG, Belo Horizonte
Joined Oct 2006
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Hey John,

Just finished an conversion here for an European Spider, Alex XXL, same plane, just polled the ballast tube off, cut the nose for a 35mm Spiner, cut a servo bay under the wings right behind the joiner.
The motor came from Germany , It´s a PeggyPepper 2524-2800KV Prop is RF 16x16 slim on 4s 110MPH PichSpeed on 96amps 1400 watts, can go to 15x16 on 5s less then 110amps and 2200watts.
The motor is an OUTRUNNER on 5:1 planetary (tinny) and weight only 145g.

Check it out!

http://www.reisenauer.de/artikeldetails.php5?aid=1785

Cheers!

André
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Old Oct 23, 2014, 05:35 PM
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United States, SC, North Augusta
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Andre,

I have only performed one flight on mine, but plan to get some serious air time this weekend. Perhaps we can compare notes after some more flights.

Going to fly on 4S/2700/70C for a little while and then switch to 5S/3300/70C. Received the 5S yesterday and it's going to be a tight fit, but feel sure it will work.
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Old Oct 24, 2014, 09:06 AM
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Australia, ACT, Kambah
Joined Feb 2001
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Hmmm. Looks like mine (AlexE XXL) could use a serious power upgrade. Bought second hand, it has a Neu 1112/1Y (Kv=3500) 6.7:1 and weighs about 80oz. Currently running 3S and a 17 x 11 which IIRC uses barely 500W. It actually performs pretty well but as it will never thermal as well as my 3.6m Pulsar I think I might as well hot it up.

I gather I should be comfortably able to prop the 1112 for at least 1000w in short bursts, so maybe sticking with the 17 x 11 but running a 4S pack that can deliver 90A would be the easiest bang for buck

My other option is a 15063D/6.7, but despite being significantly bigger and heavier than the 1112, Neu rates these with a lower max power??

I'll target 900-1000W to start with but I don't think I want to go much past 1500W. Any thoughts on whether I could do better with the 1506, or just stick with the 1112?
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Old Oct 24, 2014, 09:50 AM
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Greeley, Colorado, USA
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Scirocco,

I'd prefer to run the 1506 in that model. That motor would easily handle a 17x13 on 4S.
Later on it would be an easy swap to a 1509 or 1512 motor if you want more power.

Lenny
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