QuadPlane Conversion of Volantex Ranger EX (Part 2)

Greg, I understand that you have abandoned the Ranger conversion, and moved the gear over to your FX-79. Did you find the ranger unsuitable for conversion compared to your other conversions? I have all the parts for the ranger project, but have considered transferring this to my own FX-79 after reading your blog. It seems you have found it a better candidate?

Hi Will,

It’s a valid question and my answer has changed with my experience and needs. During my testing of the Ranger EX, I had two sets of wings. As I tested various things to get the QuadPlane conversion working, I was having great success flying it as an APM plane and less success flying it as a QuadPlane. The Ranger EX quad wings became cumbersome with the relatively weak wings not meant for the added weight and twisting and the cables needed to help stabilize them. Other folks, like Rollys and Jacques, have had success but they have also modified their wings.

One of my original goals back when I did the smaller Bix3 conversion was to use two sets of wings so that I could go between a plane and a QuadPlane. The mini Talon conversion convinced me there is merit in a dedicated QuadPlane design. Since I enjoyed flying the Ranger EX as a plane and I could take off from a field without tossing it, I decided to move on to other projects.

I searched a while before I landed on the FX-79 two meter wing. The price and dimensions seemed right and I loved the huge bay area. So far, my conversion project has been a great deal of fun. The wing design and strength required no modifications and I will not have to hand-toss it to get airborne.

It may officially be Spring but we still have snow on the ground here in Upstate NY. I have over 20 test flights backed up and the FX-79 is near the top of my list. So, time will soon tell if this conversion is successful.

Thanks for the response. I’m thinking about switching to the FX-79 also do to the issues others have had with the EX wings… I do have a boxed FX-79 and have already purchased all the quad parts you recommended for the EX. How confident are you in this conversion? I already have "most " of the parts, So I might go ahead and jump in instead of waiting for your forward flight findings.

hi Greg! thanks for your posts. very good. thanks to you I built my plane. my video

Hi Serj,

It looks great! I like your landing legs. What model is the wing?

model skywalker x8 with wing extensions. legs 3d printing

Nice work Serj, I like your landing gears too, can you share the STL? Thanks

ok, gala six day storage
rear legs for 16mm tube

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Nice, thank´s you serj

hi ! I tried the transition mode yesterday.I think the problem with CG. transition issue

You need the same cg in quad and plane and same incidence too. My first fly fail, incidence issue.

Hi Greg,

I’m not sure if you experienced any problems with your airspeed sensor. But in my opinion, the pitot tube should be placed where you have no turbulence from the fuselage. If I look at the pictures, it’s very close to the side of the nose body.

Did you consider just letting it sticking out from the tip of the nose?

Hi Anthony,

At the time, I installed it as an add-on so it was an easier mount right through an existing opening. What you say makes sense but it has been my experience that my mount position works fine. Below is my last flight from September '17 when I tested my new power system. It was a calmer day and the AS sensor tracked the GPS ground speed just fine. I hope to have more fun with my Ranger EX on Memorial weekend as a plane.


I’m not sure what caused such a violent attitude change. In addition to checking your CG, as cala2 suggested, test your elevon control on the ground in FBWA mode. Also, make sure that you have SERVO_AUTO_TRIM enabled.

Good luck!

Thank you, Greg. I counted the CG and moved it 2 inches forward. everything is good, beautiful
very good


Congratulations! Very nice flight!

Hi Greg, Thanks for the all of the Volantex Ranger EX series info. I’m doing a small project using Pixhawk 2.1 Cube, Having a bit of a trouble getting the ESC calibration done, Is it possible for you to let me know how to get this sorted. Current using the


I have never used a Pixhawk 2.1 Cube. The ESC Calibration Procedures in the APM Wiki should work fine for you.


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Hi Greg, Thanks for the info. Managed to get it sorted. Still, having an issue in getting one Aeilron working, any thoughts on how to assign AUX rail pins to get the job done? I appreciate your support.

You simply assign the appropriate SERVOx_FUNCTION for aileron. For example, if you want AUX2 to also be an aileron control, then set SERVO10_FUNCTION to 4. This gives you a completely different set of Reverse, Range, and Trim settings from the main Aileron output on 1.

From the WiKi:

This is useful when you want to trim each aileron separately.


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