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SunBird Ornithopter

I drove to Peaceful Valley on the last day of NEAT, 2003. As I entered the park, there were several tiny dots buzzing over the meadow - and among them, one lone bird. My eye stuck on that brave little bird flying out there among all those propellers. Of course, I knew that it wasn’t just any bird - it was the latest entry into the ornithopter market – the SunBird. And at that moment, I knew I had come to the right place.

Splash

Introduction


SunBird specs:
Aircraft type:Ornithopter, Hand launched R/C Park Flyer
Designer:Sean Kinkade
Motor:Speed 300 D.C. electric motor
Battery required:2 cell 7.4V High-Discharge Li-Poly, 340 to 1200 mah
Construction materials:G-10 Epoxy-Glass, Carbon, Aluminum, Steel, Delrin Plastic, Polyester Fabric, Dacron
Wingspan:about 35.5 inches
Length:about 21 inches
Weight:about 8-10 ounces
Receiver:Hitec Micro 555
Flight speed:5 to 20 mph
Flight times:with 2 cell 340 mah Li-Poly = 4 to 6.5 minutes
Flight times:with 2 cell 600 mah Li-Poly = 7.5 to 12 minutes
Flight times:with 2 cell 1200 mah Li-Poly = 15 to 24 minutes
Wind speed:0 to 8 mph
Flying area required:field about 40 by 40 yards
Sponsor:JGRC

I drove to Peaceful Valley on the last day of NEAT, 2003. As I entered the park, there were several tiny dots buzzing over the meadow - and among them, one lone bird. My eye stuck on that brave little bird flying out there among all those propellers. Of course, I knew that it wasn’t just any bird … it was the latest entry into the ornithopter market – the SunBird. And at that moment, I knew I had come to the right place.

Like all other Kinkade products, the SunBird has a unique quality that brings it to center stage anywhere it flies. While other ‘birds’ buzz about, powered by blades or jets, ornithopters are driven by flapping their wings. Because of this, no matter what else is going on, your eye is drawn to them!

I parked as quickly as possible, and went searching for the JGRC booth. Jeffrey Goodman, I knew, would have a multitude of these beasts on display, and he had promised to hold one for this review. When I found his booth, I was not disappointed. He had all manner of bird-like creatures hanging in his tent. Unfortunately, a crowd had gathered there, so I went on a walk to see the rest of the Fair before focusing in on the objects of my fascination. I’ve got to say that this event was everything I had hoped it would be! If you ever have the opportunity to attend NEAT, you really should do it!

After checking out most of the booths at NEAT, I worked my way back to the JGRC tent and finally met up with Jeffrey. We had talked on the phone and by email numerous times, but this was our first face to face visit. Jeffrey has been my long distance ornithopter instructor, and he walked me through the process of taking my ParkHawk from an egg in the nest to a fledgling in the sky. So, as you might imagine, I thought this was pretty cool.

After we visited a bit, and to my surprise, Jeff said, “Let me introduce you to Sean”, and we went back behind the tent to a van. Sean Kinkade is the designer and manufacturer of these ornithopters, and therefore another great guy in my book. (This was turning into a Blue Ribbon Day!)

There was Sean packing up the bird I had seen flying as I drove in to the park. When he found out that I was doing this review of the SunBird, Sean said “Let’s go fly one!” And after picking out a tiny little Li-Poly pack, (a Kokam 2 cell, 340 mah), we headed over to the field. I couldn’t believe that itty-bitty pack could do what it did!

Initially, Sean offered to let me fly her, but the winds had picked up, and were gusting upwards of 15 knots. As much as I wanted to fly, I did not want to be the guy who crashed a SunBird at NEAT! In fact, I actually had a flash vision of the NEAT Herald with a banner reading: Rose Crashes Again! So, I declined the offer, and instead spotted for Sean. While spotting, I also took some pictures and video of him playing in the wind.

The first thing I noticed was that Sean launches his birds with considerably more “up-toss” than I do. When I launch one, it goes out level, and often dips within inches of the ground before I establish a positive rate of climb. (You might say that ground effect is my friend.) Sean, on the other hand, tosses the bird upwards, at about a 30 degree angle, and she never looks back!

Like the larger ParkHawk and SlowHawk series Kinkade ornithopters, the SunBird is equipped with a Speed 300 motor. But the SunBird is smaller and lighter than her cousins, and because of this, the bird has several defining characteristics that set her apart. She climbs with authority, and maneuvers with ease. Although my ParkHawk would have cringed at these winds, the SunBird took them on with enthusiasm.

Downloads

Her flight is quick and lively. In comparison to the larger ornithopters, she is more ‘birdlike” and darts about with the agility of a blackbird, rather than the swoopy flight of a parrot or hawk. She would love to torment a ParkHawk. With her great response time, she can turn instantly. In these conditions, Sean was forced to use full throw on the joystick as he literally worked the currents. Never-the-less, even with the gusting winds, he was able to maneuver through them with full control.

Downloads

SunBird in Flight   3.21 MB

The demonstration flight was absolutely great, except for a minor technical problem. As she climbed, dived and circled over the field, the SunBird reached the outer limits of her receiver. Then, while she was shooting downwind at about 500 to 600 yards out, she simply went berserk and fluttered to the ground. My nightmare! To make matters worse, her ESC failed to shut down. Instead of shutting down, the SunBird hit the ground and continued to flap and flop and bounce.

I was certain her wings were destroyed, and rushed out to try to catch her, and then turn off her power switch. But, upon inspection, we discovered the bird was in mint condition! This was an outstanding statement about her durability! However, it was also an eye-opener about her range requirements. While a regular remote control airplane may become a tiny speck at a short distance, a like sized ornithopter maintains a larger visual footprint. In addition, because of her wing movement, ornithopters are very easy to see and keep track of, at a greater distance. Therefore, it is also easy to get too far from micro-receivers that are limited to the 1000 to 1500 feet range. Since “any landing that you can walk away from is a good one”, these were in fact, good landings. Even so, because of these unplanned layovers, I decided to equip my SunBird with a full range Hitec Micro 555 receiver.

Downloads

Kit Contents

When I arrived back home with the kit Jeffrey saved for me, I found it was complete and contained everything I expected. It included the unique flat fiberglass body and Speed 300 motor, as well as carbon spars, sails, a new bulletproof wing hinge, and a great newly designed tail assembly. All I needed to supply was the micro-receiver, an ESC, two servos and my choice of a battery pack. Jeffrey supplies the optimal 340 mah 7.4 v Li-Poly Packs, as well as the optional 600 mah 7.4 v Li-Poly Packs.

Construction

The assembly process was so intuitive that I needed no special instructions. To be safe, I have included a short photo essay, which shows the critical steps. But my observation is that the difficult assemblies have already been put together and that the remaining parts simply screw or snap into place. No one should have trouble with this system – it is as easy as 1-2-3.

However, the included SunBird Instruction Manual is complete and detailed. It includes everything you need to know before you build and fly your SunBird. I am stressing this, because so many RC aircraft manuals are marginal, while this one is indeed top notch. If you have never assembled one of these birds, just follow the manual, and you will do fine.

1.) Mount the radio hardware on the airframe as shown. If you do so it is virtually impossible to mess up the center of gravity. (I like Murphy-Proof designs!)

2.) Attach the Tail with the supplied “O-Rings”. I used a small Phillips head screwdriver to stretch the O-Rings over the hooks. Just be careful not to damage the O-Rings or the SunBird, as this is one of the most risky steps! The kit comes with a replacement set of rings, but they are also available at any hardware store.

3.) Insert the Carbon Spars into the Sail Pockets. Then attach the Primary and Secondary Spars to the Airframe with the supplied screws. Next secure the Sail with the two supplied “O-Rings”. This clever method of Sail attachment with O-Rings is simply amazing: it is both fast and secure and allows for a quick teardown too.

Viola! We are ready to fly!

Flying

Then there were the unauthorized flight-tests. As many other RC Groups Authors have noted, I too am virtually unable to build a stock airplane without trying out my own variations. True to my nature, I tested the SunBird with a variety of different (and unapproved) batteries and motors.

The SunBird was originally designed to fly on a larger Li-Poly pack, but after some testing, Sean determined that a two cell, 340 pack was best. The bird demonstrates it’s top performance at its lightest possible weight. Therefore, my recommendation is to get two or three 340 Packs, rather than just one 1200. Better yet, get several of each type! Even though I knew that lighter was better and that Li-Poly packs are specified, I still tried to fly mine with an old NiMh pack. (After all, I already had some 8 cell, 720 mah NiMh packs for my ParkHawk and a charger system too!)

She flew. But that was it. She was too heavy to climb, and she was on the edge of a stall throughout the “flight’. To complicate matters, as soon as I tried to bank into a turn, she rolled over and crashed to earth. After several failed attempts, it became obvious that unless I wanted to restrict myself to “straight and level”, NiMh was out. It was time to enter the 21st century and give up on the ‘cheap’ solution.

Meanwhile, I also tried to use a couple of larger HS-81MG servos that were languishing in my RC Parts Box. The recommended servos are HS-55’s but I wanted to see how she did with the stronger metal gears. Wrong! With those relatively massive servos, my little SunBird was tail heavy, and very difficult to control: she was dynamically unstable and required constant stick action. Knowing this: use the recommended HS-55 servos, and remember to choose a micro-receiver and ESC that is as light as possible.

I tried flying the SunBird with my Razor 300 motor and Jeti JES-18-3P brushless ESC. This combination flies very well, and has the advantage of greater efficiency and an overall weight savings of ten grams! In this configuration, my SunBird came in at 245 grams (8.6 ounces). However, there are other trade-offs here too. This little motor does not have the mass of the recommended Speed 300 motors. That mass serves as a flywheel and smoothes out the flapping. This halting effect is greater in a ParkHawk because she has a larger wing than the SunBird. The SunBird flaps faster, and is somewhat smoother on this motor, but it is still unacceptable. Unfortunately, the brushless motors that fit this airframe all lead to a visibly jerky flapping motion and that leads to excessive gear wear and premature failure of the drive train. I agree with Jeffrey that the best motor for this application is the one the designer picked: the Speed 300.

Do you remember the first lesson you learned when you were in Kindergarten? It was: “Follow the Rules!” If you set her up as recommended, she will fly magnificently. If you deviate, she will barely fly - if she does at all. So get the right hardware, and do this one by the numbers.

Conclusion

I told Sean that my ideal ornithopter would be one that could soar with a buzzard like quality yet still handle winds when needed. Unfortunately, an ornithopter which soars well will not handle winds; and one with great handling characteristics can not soar! As it turns out, after NEAT, Sean decided to play with this idea, and fit a larger wing on a SunBird. The result was a soaring SunBird. Therefore, with a stock SunBird, and an optional soaring wing, you can have the best of all worlds! Based on the prevailing wind conditions you can now pick your sail and go fly: this baby does it all!

In a word, the SunBird combo is the ultimate airplane! (And I can barely wait for my new soaring sail to arrive!) She is touchier than the larger ornithopters, and would be more challenging for a beginner. However, she is also quite durable, and can take more abuse than her older cousins. This is a fine bird, and I give the SunBird two beaks up!

Discussion

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Old Jan 29, 2004, 07:56 PM
Mitch G's Avatar
Naperville, IL USA
Joined Nov 2000
1,886 Posts
This looks like a fine way to use a 2s1p ETEC 1200 pack.
But I don't see the Sunbird listed at JGRC.com. Is it not released yet?


Mitch
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Old Feb 01, 2004, 08:59 AM
Isaiah 40:31
yukondog's Avatar
Buckley Washington, USA
Joined Feb 2004
335 Posts
I wonder if an AXI outrunner brushless motor would work? It would be lighter and the outrunner should have enough mass to smooth out the flapping.
A 2808/20 perhaps.
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Old Feb 04, 2004, 10:25 PM
I'm Me Again!
Jerry Rose's Avatar
Joined Feb 2002
434 Posts
The bird has been released, and JGRC had them. I suspect he has sold out of his SunBird stock. There are several other suppliers, and they are being listed in the Ornithopter Forum at this link: http://www.rcgroups.com/forums/showt...hreadid=195416 - "Where to buy" is the thread name.

As for the Outrunner, we have discussed it, and it simply will not fit the airframe on the SunBird. Otherwise, it sounds like a really nice idea. But maybe someone will find a way to work it out. Then it would be a GREAT idea!
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Old Nov 16, 2009, 09:16 AM
Registered User
Joined Jul 2008
264 Posts
I am trying to find out what are the gear ratios used in this bird. Also, how fast is the flapping motion, in flaps/minutes. Does anyone know?

Thanks
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Old Mar 01, 2013, 03:26 PM
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samson55's Avatar
United States, IL, Rockford
Joined Jan 2008
568 Posts
My friend and I found a stock of Sunbirds hiding out at a hobby shop. We ordered three in different color combos. I hope to get mine up and flying soon for a trip down to FL. Does anyone have an idea what wings worked or were used for the Sunbird XL. I wanted to ask dear old Sean that question..
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Old Mar 02, 2013, 01:12 AM
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Machy2k's Avatar
Ft Lauderdale, FL.
Joined Jan 2007
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Quote:
Originally Posted by samson55 View Post
My friend and I found a stock of Sunbirds hiding out at a hobby shop. We ordered three in different color combos. I hope to get mine up and flying soon for a trip down to FL. Does anyone have an idea what wings worked or were used for the Sunbird XL. I wanted to ask dear old Sean that question..
Samson; Hi man some of the rest of us would like to get in on that also mate...
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Old Mar 02, 2013, 07:48 AM
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United States, IL, Rockford
Joined Jan 2008
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I sent you a PM machy to give you a chance to get one. There are only three left. I am totally surprised there was still a stock of them.
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Old Mar 08, 2013, 02:48 PM
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Machy2k's Avatar
Ft Lauderdale, FL.
Joined Jan 2007
2,241 Posts
Hi Samson; thanks for the info. mate, i just picked up a Sunbird also...
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