Sky Viper v2450 GPS

I would check the plug connection betweenj the soniX and flight board it may have come lose some how . When powered on what lights are flashing on drone ? Also try removing the SD card and booting up drone see if it connects then . If you can get Wif to work direct Brower to check for error message in system status tabs . My Sv2450 will often give a gyro not calibrated error . Which prevents it from arming for no apparent reason. Quick calibration on the APWI fixes it .

You might also try

And even following the steps on that page for re-flashing the firmware on all boards.

We bought from target. … I contacted it support and they advise the same but I am in pk and can’t send that back… if can help me might be that is software issue and if one can guide me to revert all setting to factory installed might help.

Thanks in advance.



follow the link i already posted to do just that

Hello, I am a dedicated sky viper customer in Salt Lake City at 4200’ asl. The Sky Viper series has had numerous improvements leading to some additional flight weight. I believe that the 2450 (2018 model as evidenced by the new prop guards and picture quality) and 2700 motor failures I have experienced are due to the lower air density here (temperature and turbulence as well) combined with the new model weight increase. The prop guards, (which I don’t use due to performance loss) have been redesigned, I believe for this reason. At times the drone seems to be barely able to maintain altitude/position. Does anyone know of a solution for a high(er) altitude environment? Other manufacturers offer different propellers, but I was also wondering if a change in gear ratio could compensate for 15% thinner air? Thanks!

I would imagine changing the gear ratio can give you a little more torque, but also may affect the longevity of the motors as well. These brushed motors just aren’t very durable, and that’s just the nature of the technology really.
Perhaps props which make better use of the available air are a better bet. You might even be able to find motors which have more power, but I think these little guys are probably on the edge of the performance you can get at that size and weight. I also have seen some threads where people are successfully integrating ESCs and Brushless into this model. That’s an option for more power. But this thread shows it on a new frame…

Good luck finding something that works

Hello again!
For the Sky Viper v2450gps version, anyway, the motors are indeed at their limit. I have seen the stock setup wind down in as little as 2 hours flight time! I am looking for recommendations on new brushed motor options. Possibly the Micro Motor Warehouse or other 8.5x20mm varieties (that maybe are a bit more economical than $27.00 p/set for the MMW’s?). What rpm is the current model using? I believe that I’m seeing 1760rpm @ a learned hover of 53.17% meaning a maximum motor speed of 17k? Are the actual numbers listed somewhere?
Upgrading to a new prop (one that doesn’t flex?) has helped tremendously. The new props are significantly quieter. Autotune mode shows much less bounce and f/c corrections are more precise. Position hold “wander” is reduced by orders of magnitude. Rate of climb and more importantly controlled decent are similarly improved. Although top speed is only slightly higher, the drone gets there much quicker. “Bullnose” profile props appear to provide all the additional surface area needed to compensate for lower altitude density. Adding a third blade ended up not being as necessary but still makes for an impressive acceleration upgrade that I am going to stay with (Gemfan 5550 bn3b). Autotune’s 1"-2" bumps become 3"-5" jumps at a cost of about 5%-7% flight duration. Dropping to a 13t pinion may be necessary at this point to ease motor load (i.e. longevity) and potentially extend flight duration a bit. Again, knowing the design rpm considerations for the motor/propeller on this drone would be most helpful. Am I going to have to throw a $30.00 set of 17k motors at this thing? Thanks, SE

It’s been measured by others as somewhere near there.

Very interesting. What props are you using?

Aloha Brad, I am currently using Dalprop 5544 Cyclone 3 blade props. They are quiet, smooth, fairly fast and have great control authority. The Gemfan 5550 3 blade bullnose are hard to come by and expensive ($4.00 p/pair @ B&H). They pull too much air and require an 11t pinion to calm the SV down. That setup though, is the fastest, makes a bit more noise and are “wilder” than the Cyclones. I tried some Gemfan Wind Dancer 5042’s, they do not generate sufficient thrust and allow the motors to overspin.
Speaking of motors, the factory jobs are not up to the task for the heavier v2450/2700 and slowly died after less than 2 hours f.t. I found some Crazypony motors for $20.95/8 on eBay. Although they sound as if they are not spinning as fast, they appear to have more torque than stock. The leads were too short and they all spun ccw, but after some soldering, I couldnt be happier. The Viper’s personality is so much better with these motors. In retrospect, I would probably go with the Micro Motor Warehouse 17 or 18k (“insane speed”) motors equipped with long 11t pinion gears (not the MMW versions). I am starting a new build project and didn’t want to spend the $27.00 plus. That was probably a mistake as those motors will likely bring the SV’s t/w up to an even more acceptable level. That being said, the CrazyPonies are definately a big step in the right direction!
Go little Viper, go!!! What a great project!
Good luck and N’Joy, SteveE

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5544 Cyclone would be great at sea level. Otherwise the Gemfan Code Red 5550 2 blade.

Quick frame reinforcement system using modified propeller guard to frame inserts, pultruded cf tubing, and heat shrink. Obvious improvement in flight performance at less than 1 g per pair and minimal aerodynamic penalty. Note Gemfan Master Airscrew series 5550 bn3bl props! What you can’t see are the Crazypony 0820s and now non functional, snake shaped prop shaft. (crash damage). Silicone traction deck air pockets provide nice shock protection. When it flies, it flies well. Too bad. Bearings ordered, any suggestions on the prop shaft/reduction gear?

YOU HAVE GOT TO BE KIDDING ME! Frame fix for less than a dollar! Performance Hack!

O.K., you know the drill, try to decend from on high, but it won’t, now it’s rolling and pitching back and forth, oh no (you didn’t know about Acro and sensors either), wham, darn hard landing - or -
The thumbs off GPS position hold drift that becomes an expanding, accelerating helix until the battery dies, impact, or worst of all, attempt to RTL!
I knew my frame was flexing, getting softer and taking a beating, just not how much this affects every single aspect of performance. As a result, I will doubtless avoid injection molded frames in the future…
…so now what? I was measuring for some braces I’m building to try and straighten/stiffen the frame. How to hold the frame in place to get proper measurements? Bingo! The same way the Sky Viper will fly from now on! $0.45 worth of Spectra kite line carefully wrapped around, and pulling in on the motor lowers completely firms up the frame like a bow and string and brings the motors back into alignment. “Literally Night & Day” (sorry, had to). The frame is now as stiff as a new 4mm carbon X race. My v2450 can now (position) hold completely still. Really! For an entire charge, even with a bit of breeze/turbulence. Duration over 7:45 on stock 1200. Wow. Who knew? Learned Hover @ 35%, down from 53% and it’s quick as a cat now. I’m really surprised.

The kitchen sink slip jaw pliers solved my other problem, power robbing gear lash. Turns out the reduction gear/prop mount was slowly slipping off of the shaft, which was then easy to bend. A gentle squeeze. Very Gentle, and full performance restored, even newly realized. How do I start a new “string” for this frame fix? Please repost! Good Luck with your Sky Vipers, folks. I’ll continue with mine but a new Viper inspired 250mm race build beckons.


Exactly what and where did the props come from? I Need to do a similar upgrade.

If these aren’t the ones he’s referring to, they are close: 3-Blade FPV Bullnose racing / Freestyle Propellers- 5x4.5 Prop Set x4 Black

These props will slide over the prop posts, but the key to keeping these props firm is the screw. Look closely at his pic and you will see a washer-system fashioned at the screwhead of the prop. I’ve used flat head screws before that look like they have a washer built into the screwhead. The screw diameter of the toothed screw is a M2.5 or M3, I believe… not 100% on that, though. I’ve made a few of these around the shop before, but please be aware that you are slinging a LOT more plastic and the Brushed motors don’t like the extra strain. Brushed motors will degrade faster when they are taxed with more torque.

Motor tests with differing prop setups on 20 motors sets on the bench saw a motor life drop to about 1/5 of what we needed when slinging the 3 prop blades. When it works, it’s GREAT, but expect to replace motors often.

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Sorry for the delay, I’ve been working on a new airframe. It is actually designed around the same props. The ones you see are Gemfan 5550 bn3bl. They came from B&H but were expensive and slow. I’ve seen them elsewhere on the Goog, USA site for half. I also found that the Dalprop Cyclone 5544 works if you need a low gear or likely a better option at sea level, very quiet and precise. They are 3 blade as well. I have also ordered bearings and both 11 tooth and 13 tooth gears to experiment with! With the Gemfans, my Learned Hover Throttle dropped from 52% to 31.15%, a dramatic improvement. I have also swithched to Crazypony 0820 motors that spin slower but have more torque and accel while lasting at least 5 hours @ (8/$22.00, some soldering). Hence ordering the 13t pinions. Last, Micro Motor Warehouse has motors from 14k-18k. I’d like to experiment with 17k & 11t. Stock props have way too much flex, esp. camber, and make too much (inefficient) noise. Good Luck! se Oh, and also, I used about .4mm of 2mm id silicone fuel hose as an expansion washer, It sticks up maybe 0.1-0.2mm above prop hub. Close fitting 2mm i.d. flat washer is key, as it compresses tubing which locks up against the inside of the prop. Good eye.

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$21.00 to the door, kinda makes the mods I developed unnecessary, tho parts will eventually dry up for a discontinued model…

I don’t think it’s unnecessary. Look at the Karearea frames. They have the same configuration using struts front to rear. Reviewers claim a more precise feel in turns and flips. Would like to hear your impressions when you fly this new frame and then add the struts to see if you detect a difference.

I will be creating the struts like you did. Where did you get the CF tubing?

Aloha! Yes, I’m not tossing them. They are the smallest pultruded cf in the Rock West Composites web site. They have a location that used to be within range of my house…
…sorry, no spec but it is the smallest hollow tubing in their catalog, pultruded and cheap. The string mod is actually more important, much more effective at thrust line alignment, and will come into play as the poly ages. Luck! se

IIRC the original DJI Phantom had a string tensioner going around the outside of its span.