My Li'l Poke uses a Great Planes ElectriFly 4CH FM receiver with an ElectriFly C-10 electronics speed control (ESC), two Hobbico CS-5 Nano servos (rudder and elevator), a Futaba S3106 servo (aileron), and a Great Planes ElectriFly T-280GD Park Flyer Motor System. For now, it will use an 8-cell NiMH, 650 mAh battery pack. Final weight is 13.4 ounces (advertised is 12.5 - 14.5 oz). See detailed photographs below.
|Here is a short clip of the 1st flight|
On Sunday, February 19, 2006, I finally, after four months of building, took it out for its maiden flight. After exercising due diligence with range checking, battery tests, control checks, etc., I confidently took off. The Li'l Poke tracked straight as an arrow and lifted off beautifully. In the first turn I noticed what seemed like a momentary loss of control, but figured maybe the excitement of flying a new plane clouded my judgment.
After another turn, it happened again and I knew something was wrong. At an altitude of about 100 feet, I turned to land and the plane literally dropped out of the sky and headed straight down. By some miracle, when it was about 15 feet off the ground, I regained control and landed with a hard thud, and no visible damage.
|Whenever a device that emits radiation (intentionally or unintentionally) is to be licensed, test results from an approved testing facility must be submitted to prove compliance. Along with the numerical results, internal and external images are submitted. Clicking on the two image to the right will open the FCC documents with full-size versions.|
Some post-flight testing revealed that the receiver exhibits an almost total signal null at a couple different transmitter (Futaba 6 ch) antenna positions. It does not matter whether the Tx antenna is collapsed or fully extended. As a 30-year RC flyer, I know how to properly install a radio system in an airplane (and helicopters) and extend the antenna outside the aircraft. I have never seen anything like this complete loss of signal with certain transmitter antenna positions. What it tells me is that the receiver is woefully inadequately designed or it is the victim of very poor manufacturing quality. In the future, I will stick with Futaba radio gear exclusively, since in over 20 years of using it I have never had any kind of failure.
Stay tuned... One of the new Spektrum DX6 spread spectrum RC systems
(from Horizon Hobby
) operating at 2.4 GHz has been ordered and will be installed in the Li'l Poke. The system has a dual redundant transmit/receive scheme with interference-free operation. Update: the Spektrum DX6 radio was installed and has been working flawlessly - absolutely no interference problems. I've has the Li'l Poke up probably 500-600 feet to do spins, and have never had any loss of control. This is a great system!!!
Here are a series of detail photos
that show radio and motor installation, as well as some shots of the pushrod and control horn hookups. Covering was Coverite Coverlite with Balsarite adhesive. The Coverlite covering is unbelievably strong for its weight - it is even hard to tear on purpose. The only aspect I do not like about using it is having to paint on the Balsarite adhesive (the covering does not come with adhesive applied). The inconvenience is that every place the covering needs to overlap, you need to paint a line of adhesive where the overlap will occur. Consequently, you cannot the tops, bottoms and sides of areas in a single session. Another really nice feature of the Coverlite is that it stretches and shrinks extremely well with both an iron and the heat gun. I was able to cover the compound curves of the turtle deck and wingtips in single pieces (per side) without any wrinkles - amazing!
The ailerons proved to be almost totally ineffective, so I decided to remove the servo to save weight, and glued the ailerons in place. They could be cut back out and used again, but it really is not worth the trouble.
The first frame pictures are available now. Lightening holes were drilled in all the wing ribs, and lightening holes were cut in the fuselage. There just did not seem to be a good reason to have that balsa sitting there just adding weight. I have to say that Great Planes did not do a particularly good job engineering this kit. Fuselage side lengths matched the plans when flat, but ended up short when curved as they actually go together. The polyhedral joints are implemented very stupidly. Only the root rib for the outboard panel is slanted to accommodate the dihedral, rather
than dividing the slant between the center section end rib and the outboard section root rib. What happens is that the root rib for the outboard section is necessarily taller than the others because its length is that of the hypotenuse of a right triangle. That means when the two wing sections are butted together for gluing, there is a about a 3/32" high step at the joint. As I said - really stupid. It caused me to have to add a strip of balsa in from TE (trailing edge) to LE (leading edge) to smooth the transition. The other unforgivable blunder is that the plans show the bottom TE balsa sheeting in
the wrong location. It actually sits about 1/8" closer to the LE than what is shown. Although not called for, I decided to add some 1/32" stiffeners to the open areas between the ribs on the wing TE and the front of the ailerons because leaving them open creates an very weak and crush-prone edge. I can't imagine why GP does not do that. Finally, I chose to use a DuBro miniature tail skid instead of the one built out of 1/8" square balsa per the plans. That balsa version, even when saturated with CA, cannot last long. The entire frame has been coated with CoverRite's BalsaRite, in preparation for covering with CoverLight.Earlier Post:
There is an interesting story to go with it already, though. First, I'll say that of the many Great Planes kits I have built in the last decade, all have had very good quality balsa, bass and plywood. Their hardware I have never particularly cared for. Anyway, the Lil' Poke is a backyard flyer and thus should be constructed of lightweight balsa. Well, all three 1/16" rib sheets and the two 1/16" fuselage side sheets were the hardest balsa I have ever seen anywhere. It was harder than the stuff that used to come with the Guillows free flight rubber kits. In fact, I weighed it on a postal scale an calculated the density to be 18.3 lb/in³ - off the charts for balsa density! Medium density balsa is 6 lbs/ft³. Tower Hobbies replaced the sheets on request, so I'm satisfied. I offered to return the original sheets to them, but they did not want them. The recommended motor/gearbox and airborne flight pack were ordered to go with it.
Here's a handy trick I just discovered: While cutting and sanding the many balsa sticks that make up the Lil' Poke, many times I end up sanding off just a tiny bit too much to get that perfect fit. The old carpenter's joke that, "I've cut the end of the board off three times now and it's still short," actually has a cure now for this application: Dip one or both tips of the balsa stick in a drop of water to get just the right amount of swelling. Pin the stick in place and let it dry, and viola! Perfect fit!