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Old Nov 07, 2014, 05:43 PM
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Joined Feb 2013
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Originally Posted by BILLYDSRC View Post
Hi Olaf, I have built over 20 of the 90mm Vipers over the years and at 11lb to 12lb is just fine! Just land with some good airspeed the first couple of flights to get a fill of this airframe. I will tell you that if you have to much up elevator she will snap!! I hope my 2 1/2 cents helps out Billy D
+1 on what he said.
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Old Nov 07, 2014, 08:01 PM
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Ontario, Canada
Joined Jul 2005
241 Posts
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Originally Posted by ohaack View Post
Hi out there,
greets from Germany! My RTF Viper with Jetfan 90 V2, HET Motor 1200 K/V, 120A HV Controller, JTM -Gear incl. Brakes arrived yersterday. It looks great, and only thing to do is installing the RX with powersupply. I put this lady on my kitchen-scale and it shows me an AUW about 5.3 KG with 10S 4500 Lipos! IŽm afraid, its to heavy? I heard about weights around 4,5 KGs with Turbines.....

And, for a guy like me, coming from 3D-Flying, ist hard to believe, that the Viper will show no tricky landing-behavior at this weight!! What are your experiences
esp. with high-wingload Vipers with AUW around this mark (5,3 kg and more)....


Thanks and greetz from northern germany.

Olaf
Just want to confirm that you have the motor nomenclature correct. The 1200 kv motor is usually used with 12S. I am using the 1400KV motor on 10S and it is a nice setup.
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Old Nov 08, 2014, 02:59 AM
ohaack
Germany, SH, FL
Joined Nov 2013
7 Posts
Thanks guys for your replys, slept a lot better last night ....

Mine is the blue white silver... one, got it from a "garage-sale" at RC-Network, the german equivalent to rc-groups. The pre-owner built it up for his son, but the bird never maidened.

@pylonboy: yes its a HET 1200 KV, Datasheets from www.Ejets.at shows thrust around 3,9kgs and little above 70A current with this setup. My flying field is a close-cropped, plain grass-airfield, large enough for long takeoff-runs. Maybe going on 11S? Now i know iŽll have a little room to grow on AUW issues.

Olaf
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Old Nov 08, 2014, 03:59 AM
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now that you mentioned that you are flying off grass I would use 11S. don't mind the extra weight.
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Old Nov 08, 2014, 08:29 AM
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Ontario, Canada
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Originally Posted by pavlis View Post
now that you mentioned that you are flying off grass I would use 11S. don't mind the extra weight.
The weight even with 12S 4500mah pack will be ok. If you have lots of room for take-off the 10S will work, but you can move up to 12S in the future. I think you may want to later on.

I think I speak for everyone................I want a video!! Good luck and have fun.
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Old Nov 08, 2014, 08:57 AM
ohaack
Germany, SH, FL
Joined Nov 2013
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Originally Posted by pylonboy View Post
I think I speak for everyone................I want a video!! Good luck and have fun.
I Žll start with 10S, but think you are right, ..it ends up at 12S later.
Video? Thats obvious

best regards

Olaf
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Old Nov 12, 2014, 12:15 PM
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OHIO
Joined Aug 2009
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HI All, The days of 2014 are coming to a close very fast So here is the Best deal of the year on any JTM 90mm Viper jet from UsaRcJets!!
Thank you Billy D
$699.99
http://www.usarcjets.com/cgi-bin/sho...7.htm#Jets!JTM
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