A Couple of UMX Radian Videos

Here's a couple of videos of my UMX Radian, a really sweet plane.

Quiet morning flying at the Berkeley Marina

Here it is with a wing mod that makes it into a really slow flyer.

And pretty sweet indoors.

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Fixing UMX Radian Porpoising

BrownShoe at RCGroups posted a note about eliminating porpoising on his UMX Radian.

After I established the CG at 32 mm, I cranked in some negative elevator with my needle-nosed pliers; the little U-bend was almost closed. She flew kind of crazy. It was way too much negative elevator and the wind was very choppy and I came close to crashing. What I noticed was, it did not porpoise! Ha! I landed and opened up the U-bend some and tried again. She flew with nary a dip! It was the nicest flight she has ever flown!  

I performed a dive test as best I could while trying to remember what to look for. It had a nice gentle rise and not an abrupt porpoise. Nice! I flew three packs and she handled very well in spite of the very choppy air. I let it glide hands free for a good ten seconds. Finally it flies like it is supposed to and I'm having maximum joy now. 

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"Mod C" Slow Flying UMX Radian

Here's an interesting mod by Rick Rademacher.  It makes the UMX Radian fly almost like a Vapor.  I'm going to try it!


Main Wing

• obtain three Horizon Hobby Citabria wings (part PKZ3120).  Got mine here.
• overlap two wings by 3.5 inches.
• tape the wings together with a strip of tape on each side.
• insert the wings into the fuse.
• don't tape the wings to the fuse; the friction will hold the wings in place.

Top Wing

• cut the third wing in half longitudinally.
• mount it upside down on the other wings, leading edge forward.
• lightly tape each side to the other wings

Krueger Flaps

• use post-it tabs to make krueger flaps on the leading edge.
• bend tabs to desired direction and shape.
• vary tabs to match your desired style of flight.

Blogger can't find it, but the howto video is here:

https://www.youtube.com/watch?v=9sXTsMXxIaY

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decalage -- lots of interesting stuff

Decalage refers to the angle between a plane's main wings and the elevator, or the two pairs of wings on a biplane.  There's a great discussion in the RCG UMX Radian thread.  I'm capturing it here coz... well you know how searching on RCG is.  Post numbers are 3431, 3434, 3435, and 3442. Big Thanks to Phil Alvarez and turboparker for sleuthing these out of the thread.

My Summary:

• Porpoising is caused by bad decalage.
• Don't try to solve by changing CG.
• Small foamies can incur twists due to their light construction.

Standard decalage test:

• Perform a power-off vertical dive from high altitude (neutralize elevator).
• A. Model continues straight down: No change needed. 
• B. Model pulls to canopy: Increase stab incidence with respect to the wing.
• C. Model pulls to belly: Reduce stab incidence with respect to the wing.

And the words of the masters:

Controlling AS3X with GEAR on the Radian UMX

Thorvald@RCGroups has a nice overview on configuring the Radian UMX AS3X system so that the gear channel can be used to turn AS3X stabilization off and on using channel 5 (the gear channel).  He's using Windows 7 and a DX8i and spent "only a few hours" pulling his hair out.

1. Install ONLY the PL-2303 Vista Driver Installer.exe. Ignore Spektrum's instructions about loading the XP driver first.
2. Plug the SPMA3600 in to a USB port.
3. QUICKLY click on the found new device and cancel searching on Windows Update (that driver would not work for me). Windows will find the driver you loaded in step 1 (2007 version).
4. Let it reboot when it asks and leave the programmer plugged in.
5. After reboot, run the GYRO_PARA_DOWNLOAD.exe as Administrator.
6. Connect Programmer to 4 pin jack inside Radian.
7. Turn on Tx.
8. Use rubber band to (mode2) to hold throttle to the top right (full throttle and right rudder). Ensure it is ALL the way to the top and into the corner. I found if you loop the rubber band around antenna and a few switches, it works perfect.
9. Plug a battery into the Radian and wait.
10. You will eventually see the red led on the board flash twice and if you look over at the PC screen, it should have found the com port and stopped "searching".
11. Click on read and save those settings (screen shot too is good).
12. Copy the settings into the info above in the modify section and change the enable via gear switch to "1".
13. Write the changes.
14. Unplug battery and programmer and remove rubber band.
15. Plug battery back in, give a little throttle to activate AS3X and then use gear switch (ch5) to disable/enable at will!

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Switching AS3X off on UMX Radian

You may have noticed I recently got the UMX Radian and have been really loving it.  One thing I've been interested in trying is puting the AS3X stabilization on a switch, so that it can be turned on/off in the air.  92PathSE@rcgroups has a great writeup on what he did to do this, reproduced below.

Executive summary:

• install driver on PC
• enable X-Port on channel 5 of RX
• attach cable to plane
• read current configuration
• write new configuration

Chuck's New UMX Radian

CME President Chuck Hill picked up one of the new UMX Radians
and brought it in to our monthly indoor fun fly. It's a sweet plane!  Lots of details at the link, but the tldr:  three channel, ASX stabilization, flies nicely, just fits into a single basketball court.  I'm going to get one!

Turn off ASX with the Programming Cable.
Linkage: UMX Radian Mods; Sailplanes; Micro RTF;

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