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Roy Walton's Eflight Designs Wyngz Review

Roy Walton's Wyngz was one of 2 designs which won the RCGroups' members design contest and were sent off to manufacturers to be kitted. Tres Wright beta tests the pre-production model of this lightweight e-powered aerobat.

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Introduction


Wingspan:36 inches
Wing Area:352 square inches
Weight:14.4 oz per manuf
Weight:13 oz as tested
Wing Loading:5.3 - 5.9 oz/sq ft
Radio:Futaba 9C, FMA Extreme 5 rx*
Servos:GWS Pico (4)
Battery:3x1200mAh Li-Po
Prop:GWS 10x8
Recommended Motor:GWS 300 or AF010**
Motor Tested:Razor 400 in GWS Gearbox
Power Loading:114 watts/lb.
ESC:Castle Creations Phoenix 25
Available From:EFlight Designs, LLC
*2nd ail assigned to ch. 5 in 9C programming.
**Please see 'designer's note' for details on brushed motors.

RCGroups.com held a site-wide airplane design contest that was open to all members. There were few rules, basically the submissions just needed to be original plane designs. Participants were required to submit plans and photos and were encouraged to build and flight test their designs. In the end, two submissions were deemed winners and deals were struck for these two entries to be kitted. One of the winning submissions was this plane, the “Wyngz” designed by Roy Walton.

Roy has been one of my “cyber” friends for quite some time; we’ve exchanged many emails but have never actually met. Roy enjoys designing and building planes and his craftsmanship is very impressive. He’s an “old school” builder, working the wood to coax a plane out of it as opposed to assembling pieces like a jigsaw puzzle as is prevalent in the newer generation of laser cut designs. Roy needed a beta tester before releasing his kit for full production, so I happily agreed to assist. Note that since this is a beta kit, there may be slight variations from the actual production kit, but if anything, the production kit will be even better.

The “Wyngz” is a 4 channel aerobat with a broad wing resulting in very light wingloading (just over 5 oz./s.f. as tested). Accommodations for dual aileron servos make flaperon mixing possible. Wyngz can really float, and with throws set low would be quite suitable as an aileron trainer. Crank up the throws and she’ll perform great aerobatics too! Her sleek lines, open cockpit and turtle deck hearken back to vintage racing days.

Kit Contents

The kit manufacturer is planning on releasing the kit in two forms: a "short kit" (containing laser cut wood, plans and instructions, and a few non-standard items like landing gear music wire and some of the hardwood), and a "full kit" with all necessary strip/sheet wood and hardware. (The hardware pack will be 4 DuBro micro control horns, two DuBro micro pushrods with E/Z links and E/Z connectors, and 4 extra E/Z links and pushrods for a dual-servo aileron arrangement). The kits are due out shortly after publication of this review. The beta kit I received is close to the “full kit” version. It contained several sheets of nicely laser cut parts, strip balsa, sheet balsa and a fairly complete hardware package. The production kit will include full sized plans, although my beta kit didn’t. Instructions are well written and include plenty of photographs explaining each step. Balsa is of high quality and while I didn’t weigh each sheet, it seems to be in the medium to light range with few blemishes.

Construction

While this is a laser cut kit, it is not the self-jigging style which has become popular in recent years. It is a builder’s kit and you should expect to spend some quality time with it. With that said, it doesn’t take particularly long to build. I had the framing completed in a week’s worth of spare time, and that included making beta notes and exchanging emails with Roy mainly to clarify things that I wasn’t sure about since I didn’t have full plans.

As with any kit, it’s a good idea to read through the entire instruction booklet before starting, and also to familiarize yourself with the plans. As you progress through the construction, stop every once in a while and read ahead so you know what’s coming up next. I received separate instructions for the wing and fuse; I chose to start with the wing. I’m not going to list every detail of the construction process, just items that I feel are worth noting or clarifying.

It is very important that care be taken to build the wing structure straight and true. This is a D-boxed wing, that is to say it receives sheeting top and bottom from the spar forward. It is a very strong, solid wing; and once built is very difficult to twist or warp even if you want to. Some people build wings without much attention to twist assuming they can heat the covering and twist warping out later. Not with this wing! Build the wing over the plan (cover the plan with wax paper to keep the glued balsa from sticking to the plan), pin everything down and constantly check alignment as you go. A little attention to detail here will make the rest of the wing construction easy.

Note that the wingtips are not installed at this time. The wing will be permanently installed through holes in the fuselage sides; the wingtips get installed after that step.

Before installing the center sheeting at the bottom of the wing, decide how you want to mount your servos. I mounted all four servos in a line just behind the spar, so I installed hardwood rails before placing the sheeting. Cut the servo holes through the sheeting between the rails. The two aileron servos will be outside of the fuselage, the elevator and rudder servos will be inside (but still installed in the wing).

Ailerons and tail surface are built next. Again, build over the plans and use care aligning the parts. Don’t pin through the parts as it will split the wood, use pins on either side of the parts to “brace” them in place.

Next up is the fuselage. The plane is designed to take any motor in a GWS 300 series gearbox (GWS motor, Astroflight 010 or Razor). If you’re using another motor, you will have to modify the mount. The top of the fuselage is built up from thicker pieces of balsa. These will be sanded and contoured after the fuse is complete to give Wyngz its distinctive look. The turtle deck area is built-up from strip spruce stringers laid over the formers.

You might want to consider the routing of the control rods for the elevator and rudder at this time. If you’re using sleeved cables, install the sleeves before covering the fuselage. I deviated from the instructions and used carbon fiber rods, which were installed after the fuse was covered.

Covering Notes:

  • Before covering, make sure the wing slides through the fuse sides properly. Remember, you’ll need a little more room after the wing is covered. If the wing won’t slide in, look for the problem areas and sand that area of the openings to enlarge them. The wing should be a snug fit- not too loose, not too tight.
  • The wing must be covered before installation.
  • The wingtips cannot be installed until after the wing is in place! Not a big deal, just cover the wing and leave the ends uncovered for later mounting of the wingtips.
  • DO NOT shrink the covering on the end bays; the end ribs will be severely warped since the tips are not in place yet. Shrink everything except the end bays for now.
  • Cover the fuse, and then slide the wing in.
  • Make sure the wing is right side up, servo openings on the bottom.
  • Check wing alignment, mark and cut away covering to glue the wing to the fuse.
  • When installing the wingtips, remember to shrink the end bays of the wing that were left loose earlier.

Added security for the stab: To help secure the thin vertical stab, I “sewed” the vertical stab to the horiz. stab using a needle and thread through tiny holes in the parts (I used a pin vise to drill the holes); then I soaked the thread in C/A. I made one loop of thread at each end of the stab.

Equipment installation

If you’re using flaperon mixing, you’ll probably need a 6 channel receiver. Some computer transmitters, like my 9C, allow designating channel 5 to “mimic” channel 6 or otherwise will support 2 aileron servos on channels 1 and 5 via differential or programmable mixing; if this is the case, you can use a 5-channel receiver. I cut a hole in the wing sheeting behind the rudder/elevator servos and routed the servo wiring up through this hole to the receiver (I installed the receiver at the back of the fuselage opening). I ran a micro antenna along the edge of the fuse, directing it forward to avoid the carbon fiber control rods that I used (carbon fiber can cause interference). The Dubro E/Z connectors are used at the servo arms and greatly simplify control adjustments.

The GWS gearbox is a snug fit in the cowling. The instructions call for a wedge to secure the motor on the mount, but I prefer something a little more secure, after having ejected motors on other planes. I made a small hole in the side of the cowl sheeting and ran a screw through the gearbox mount into the wood stick. I routed the ESC wiring back and installed the ESC to the front underside of the wing (inside the fuse) with foam tape.

I use nothing but lithium polymer batteries on my planes; it’s hard to beat the power and long run times they allow! The CG is called out as ¾” behind the spar, and balance was spot on with a 3x1200 li-poly pack located just below the leading edge of the wing. I installed a Velcro strap to secure the pack; this places the pack below the fuse, which I prefer for cooling purposes. It would be possible with a little more work to create a bay to install the pack up inside the fuse, if that’s your preference.

Flying

Yeah, you skipped right to here without reading the rest didn’t you? That’s what I do on these reviews too!

I’m running a Razor 400 with a GWS “C” gearbox, on 3 li-poly cells. This is a potent setup! I started with a 10x4.7 prop, previously I’ve tested this setup at 20.2 ounces of thrust at 8.1 amps. All up weight with 3x680 HO Kokams is 12.4 oz.; with 3x1200’s, weight is just under 13 oz.

I’ve done so many maiden flights that I don’t get nervous anymore, but I still follow some basic safety rules and find a nice, big unpopulated field for those first few flights. I did a range check, set the rates on low (I am using a computer radio with dual rates on rudder, elevator and ailerons), checked to make sure the control surfaces were deflecting the correct directions, pointed her into the wind, moved to half throttle and away she went!

Takeoff roll was short, about 8’. Several clicks of down trim were required to keep the nose level, but right away it was clear that Wyngz is an amazing and gentle floater. Very little throttle was required to maintain level flight, anything above ¼ throttle resulted in a climbing attitude. I made a couple of circuits and everything was looking good, so I flipped to high rates and tried some aerobatics. Loops were easily done from level flight at half throttle. The symmetrical airfoil allows for outside loops that are as tight and easy as inside loops. Roll rate was a bit slow with some loss of altitude (this was improved in later flights with prop changes). Overall, Wyngz tracks nicely and aerobatic response is smooth and predictable. I gained a little more altitude and forced some stall conditions. No matter what the orientation, recovery from stalls was a simple mush back to level flight. There were no scary tendencies at all.

Landings are a bit tricky because Wyngz just wants to keep floating right on by, even with no throttle at all! I’ve found the best approach is to give one or 2 clicks of throttle such that the prop is barely turning, and she comes in slowly and settles down gently even with no flare.

I’ve logged about a dozen flights now, with various props, and have found the 11x4.7 to work the best with my setup. Normally I use high pitch props, but big diameter, low pitch props work best on Wyngz. I also increased the throws quite a bit. This has greatly enhanced maneuverability and the trainer-like qualities have been replaced with nice responsiveness and improved aerobatics. It takes some experimentation to find the right combination of control throw, power setting and entry approach to execute more advanced maneuvers, but I have managed to execute a blender, parachute, and spins with Wyngz. Exiting spins is a non-event, just steer out.

There’s not enough rudder throw for knife edge, but knifing might be possible if the elevator cutout is modified to allow more rudder throw. I’ve flown with and without flaperon mix activated, but elevator-to-flaperon mixing is really not needed because Wyngz loops incredibly tightly without it. I’ve been playing with up/down flap adjustments; adding in down flap slows landings down and also allows hands-off inverted flight.

The real surprise about Wyngz is that she’ll slow down to a crawl! One evening I flew out an entire pack without ever going above 20’ in my backyard. She easily flies as slow as my Slow Stick, but can carve turns much tighter.

Control Throws and CG as flown
CG:3/4" aft of spar
Ail high:1-1/2"
Ail low:1"
Elev high:1-3/4"
Elev low:1-1/4"
Rudd high:1"
Rud low:1"

Conclusion

Wyngz is a unique looking flyer that is sure to generate some comments at the flying field. The flight characteristics can be set to give trainer-like qualities, or nice aerobatics, or anything in between. While I’m flying mine on a more expensive brushless motor, frankly I rarely go over half throttle, so an inexpensive GWS 300 series motor should be all one would need to enjoy this plane. Whether whipping through aerobatics or just doing low and slow fly-bys, Wyngz is sure to make you smile!

From the designer regarding brushed motor performance:

"The 2nd Wyngz to be flown was by Michael Cripps. The power was a GWS-300C-A with an 8x4.3 prop on 2 1200mah E-Tec cells. A video of Mikes' first flight may be seen at http://www.eflightdesigns.com/gallery/index.html. To my knowledge this is the least power tried in Wyngz. I am the designer and I was surprised by the performance on this low power setup. Loops, rolls, inverted and other moves."

Additionally, this information was written for the kit that is based in part on calculation and trial:

"You don't need a fancy (read: expensive) brushless power system to enjoy Wyngz. With it's big wing and low-wing loading, just about any Speed-300 class power system that puts out around 9- 10 oz of thrust is more than adequate to motivate Wyngz through some impressive aerobatics. Since Wyngz was designed to fit the GWS EPS-300C gearbox, we will examine these in more detail. Other Speed-300 gearboxes will work as well, but may require some "kit-bashing" to mount securely. Select your gearbox based on the battery packs you will be using. Let us assume you have a lot of 2-cell (7.4V) Lithium Polymer packs of either E-Tec 1200mah or Kokam 1500mah cells. Let us also assume that you don't want to burn out your motor too quickly, so we'll select a combination that pulls around 7 amps. The EPS-300C "A" Drive (3.75:1 gearing) with an 8x4.3, 8x6, or 9x4.7 prop fills the bill (8.5 - 10oz thrust at 6-7 amps). For a little more oomph, try the "B" Drive (4.43:1) or "C" Drive (5.33:1 gearing) with a 10x4.7 prop. Your top speed will be somewhat limited (though Wyngz is about maneuverability, not speed), and you won't have unlimited vertical, but you'll still have a great flying aerobatic ship."

"More spirited performance is also possible on the cheap - as long as you don't mind running your motor past it's limits. A three-cell (11.1V) Lithium Polymer pack mated to an "A" Drive turning a 9x4.7 prop will produce 16+ oz of thrust for a greater than 1:1 thrust-to-weight ratio at full throttle. The catch is that at full-throttle, your motor will run hot - very hot, and at around 10 amps current, will be putting a heavy load on the batteries. In this configuration, you will want to pay special attention to motor and battery cooling, and only use full throttle in bursts when you really need it."

Discussion

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Old Mar 30, 2004, 02:43 PM
Live to ride... and fly!
Tres Wright's Avatar
Forney, TX
Joined Mar 2002
15,165 Posts
I built Wyngz many months ago, but it's still flying like a champ! Fun plane. Let me know if there are any questions.
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Old Mar 30, 2004, 07:05 PM
Registered User
Mobile, Alabama
Joined Aug 2002
620 Posts
Only 2 cells

Tres,

If you haven't seen this video - you should. It is Mike flying Wyngz on a 2 cell LiPo pack. 2 cells!

The plane must have seemed huge to him as he had been only flying micro planes for awhile.

I like the RealPlayer version best.

Video is on this page http://www.eflightdesigns.com/planes/Wyngz.html

Congrats on a very nice article! Is that AnnMarie's layout! I like it. Also seems to be a bunch more articles since she came to E-Zone. The one on the Jitterbug shares the layout scheme and is quite good also.


Roy
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Old May 12, 2004, 08:51 AM
PittsLover
houfek's Avatar
Ohio
Joined Jul 2003
914 Posts
Wyngz

Roy.....and Mike.....

I have been spending a lot of time with this design and I have to say it is one of the sweetest flyers in my hanger.......stock motor and an 850 to 1500 2S1P lipo is just a blast......slow as a walk or faster if desired......the envelope for that huge wing is wonderful.....and it will do it all.....as I think someone already mentioned in one of the threads, the outside loops are even tighter than the insides.....and those are tight ! Can't imagine why you would want to put a brushless on it.......and I fly a LOT of brushless planes !


Great design, Roy............and great kit, Mike.....
Congratulations to you both !!


Jim
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Old May 12, 2004, 09:08 PM
Registered User
Mobile, Alabama
Joined Aug 2002
620 Posts
Jim

Thank you for the praise! It means a lot to a designer to know "he done good".

Roy
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