RCWorks.com's Sickle Slope Glider Review

!Introduction
| spec2
| @909363
|> <b>Wingspan:</b> |< 36"
|> <b>Wing Area:</b> |< 277.5 sq. in.
|> <b>Weight:</b> |< 11 oz.
|> <b>Root Chord(without elevon):</b> |< 10.75"
|> <b>Tip Chord(without elevon):</b> |< 4.5"
|> <b>Wing Loading:</b> |< 5.7 oz/sq. ft.
|> <b>Servos:</b> |< HS-81MG's
|> <b>Transmitter:</b> |< Hitec Eclipse 7 with spectra module
|> <b>Receiver:</b> |< GWS R4P modified with ultra light gauge antenna
|> <b>Battery:</b> |< 4 X 370mah 2/3AAA Nimh's
|> <b>Manufacturer/Available from:</b> |< <a href=http://www.RCWorks.com>RCWorks</a>

I've built and flown many types of foam wings (powered and non-powered). However, I've never owned one of the 36" non-powered slope variety, which was what made this review attractive to me. Speed and ease of construction, not to mention a slope two minutes from my house, had a little bit to do with my decision as well. The final enticement was RCWorks advertisement that the Sickle slope wing was outfitted with their "Top Secret Airfoil" that promised great performance. That was it - I threw my name in the hat and was awarded the opportunity to see what this plane could do!

!What's in the box
@909364:The parts count was low which was what I expected in a kit of this type.

Definitely one of the big attractions of an EPP wing for me was the speed of assembly. As an experienced foam wing builder, I knew I could finish a kit of this type in a couple of evenings. Another plus was the near indestructibility of such a plane. Why this was important to me will become clear during the flying section of this review.

@909365:Hot wired cores in their beds, carbon fiber spar, balsa elevons, coroplast tiplets, all necessary hardware, and extra EPP completed the parts list.

!Assembly
The first thing that really stood out for me in this kit was the instructions. They were printed on thick magazine quality paper in tri-color. This was a very nice touch and the color instructions weren't just for show either. They served an important function as many of the procedures were color-coded. This would have definitely aided the first time foamy builder.
!!Core Preparation
When EPP is cut with a hotwire, it leaves slag that must be removed. This subject brought up the only complaint I had with the kit. The slag on the Sickle cores was thick and melted to the foam. Removing it was very tedious and caused some "chunking" of the EPP. This minor damage in no way affected the finished product because the plane was completely covered with bi-directional strapping and packing tape. It was just a pain, carefully picking it all off, while trying to minimize the damage. Maybe I just got a bad set and yours won't have this problem. Either way, once again, it had no effect on the finished product.
!!Assembling the Wing Halves
@909366:The CF spar slot was cut so accurately it lined up the wing halves for me!
@909367:Wax paper and a heavy chunk of steel were used to hold the wing perfectly flat while drying.
After trial fitting the CF spar and wing halves, I smeared goop on the root faces and spar slots. I used strips of packing tape to hold the three parts in alignment while the goop dried.

!!Radio Installation
@909368:HS-81MG's, GWS R4P with ultra-thin antenna, and 370mah nimh pack ready to go.

RCWorks tries to make equipment installation super simple by pre-marking the cores. Before using their locations however, I decided to do a pre-assembly. The reason I did this extra step was because I wanted to make my Sickle light and then ballast up for more wind. It was obvious my lighter gear choices installed in the stock locations weren't going to balance the Sickle. Once the gear locations were finalized, I traced the outlines with a pen and then cut along the lines with a brand new exacto blade.

@909369:The new equipment layout with my lighter gear.
@909370:I used this homemade tool to rip the foam loose at the bottom of the exacto cuts. I finished each gear cavity with a dremel grinding stone.

The instructions told me at that point to use the extra EPP supplied in the kit to make covers for the installed gear in their pockets. It seemed to me that a better option would be to use the foam that I had removed while making the pockets. I had been careful to preserve the top surface of the foam when I dug it out. Because of that, all I had to do was thin the chunks to the right thickness from the bottom. Doing this saved me the trouble of trying to sand the EPP to match the surface of the wing. My covers already perfectly matched the airfoil.

@909371:Gear installed and EPP covers glued in place.
@909372:Flyer from the receiver and the battery lead. I just pushed the mated connectors under the flap and taped over for flight.

!!Covering
@909373:Before beginning to cover the Sickle, I used 3M77 to stick the bed halves together. Then, I covered them with wax paper. This made a stable platform for the cores to sit on during taping to prevent warps.
Before covering the Sickle, I had to order the recommended bi-directional strapping tape. It was quite expensive, but I was curious so I ordered it anyway. After using this product, I highly recommend it! It was well worth the price due to its great strength and lightness. The RCWorks instruction booklet really shined during the covering process, making excellent use of the color printing. The color-coding made it easy to understand at a glance what was needed. After I finished applying the strapping and packing tape, I ironed it all smooth with my hobby iron. I set the temperature between 200 and 250 and held the wing in the bed until cool. I don't recommend this step unless the person is an experienced foamy builder. It would be very easy to permanently damage the foam and/or make it tough to fix warps.

@909374:I always try to cover the bottom of my slopers in a contrasting color to help with orientation
!!Completion
All that was left at that stage was covering and hinging the elevons, installing the hardware between the servos and elevons, and attaching the tiplets. I used 150 closed grit to bevel the hinge edge of the elevons, round the other edges, and finish sand the surface. The instructions called for applying some spray adhesive before covering, but I thought this unnecessary. Dusting off the wood thoroughly let the packing tape stick just fine without spray glue. The instructions gave a couple of options for attaching the tiplets. I chose to permanently goop them on since this is such a small plane. I was happy with the results.
!!Throws and CG
With my Sickle done it was now time to fine tune the radio settings and check the CG. The Sickle was supposed to balance 6.75" from the nose, which happened to be right on the CF spar. The instructions didn't specify any particular throws so I just adjusted everything for as much throw as I could get. That amounted to about 1/2" either way and a little bit more when full left or right along with full up or down was called for.
!!!Testing the CG
My completed Sickle balanced slightly behind the spar at 7" even after doing the pre-assembly to place the gear. Being "leadaphobic" I decided to try some test glides with that CG at the park across the street. Using the "pizza box" type launch, it took hardly any reflex to get it to keep the nose up. Straight forward glides were OK, but as soon as I attempted to bank the plane it went into the dreaded flying-wing-death-spin. It took only a few cartwheels across the ground for me to concede defeat. Out came the sticky putty and I started adding weight to the nose a little at a time. It wasn't long before I could launch the Sickle easily into straight and level and also turn with stability. When I was totally satisfied with its behavior, I checked the CG and it balanced right on the spar where the instructions stated. All this nosing in hard and cart wheeling had done absolutely no damage to the plane. Not even a dent or wrinkle. The bi-directional tape in the pattern dictated by the instructions had made this bird really tough!

@909375:Ready for a test flight using the pizza box grip.

Back at the shop I used a torch and spoon to melt an equivalent amount of lead into an appropriate shape. The amount of putty I had to add weighed 5/8 oz and brought the final weight of the plane up to 11 oz. I made a slit in the bottom of the nose, scraped out some foam, pushed in the lead with some goop, and taped over the slit. All I needed then were some good slope winds.


!Flying
!!First Day at the Slope
@909376:This was the 80 foot slope of the local flood dam just a few minutes from my house.
@909377:Even though my slope was ideal in shape and was conveniently located, only EPP could be flown due to the rugged construction of the dam.

I had to wait nearly a month for some favorable winds. Usually, this time of year the weather was hot with moderate winds from the west. I must have angered the wind gods because the day I finished the Sickle, the winds shifted to the north across the face. They stayed there and brought more rain than this area has seen for 100 years!! Finally after over a month, the wind shifted back to out of the west. Fearing that it wouldn't last, I grabbed the Sickle, the cameras, my wife, and rushed down the street to the slope. We climbed the face and I checked the wind direction and speed.

@909378:I purchased this for $20 plus shipping. It was a lot more accurate than my skin, which wasn't calibrated at all!
@909379:Getting the feel of the Sickle.

The wind was ninety degrees to the face and the wind speed was a constant 15 mph with gusts to 25 mph. It was perfect for a maiden flight! I turned everything on, got my wife with camera ready, and launched! The Sickle moved away from the crest smoothly and then began climbing sharply with a slight oscillation. A few clicks of down fixed that and then the Sickle was rock steady. I did a few speed passes across the face and was impressed with its speed range.

I also accidentally gave the Sickle the ultimate durability test about that time. While I was doing the speed passes close to the crest, I was also talking to my wife and giving her instructions about what kind of footage I wanted. I wasn't paying close enough attention as one of the larger gusts hit and the Sickle slammed into the face at full speed! It hit hard and did several cartwheels on the rocks. I was a little worried even though I knew this plane was tough. The rocks on this slope were SHARP. I walked down and examined the Sickle closely. I could see a mark on the tape where a rock had scraped it, otherwise it was untouched!! Very impressive.

!!Top Secret Airfoil Testing
Since the slope I flew at was a flood dam, the back dropped away just as fast as the face ascended. That created a huge roller by the back lip that had to be avoided. Or, atleast I thought so before the Sickle. Usually, if I let a plane get even with the lip away from the wind, the roller would take it down in a hurry. The Sickle seemed to have no problem with it and lived up to its name as it sliced through the turbulence.

The "top secret airfoil" of the Sickle was impressive in other ways as well. When the wind kicked up during gusts the Sickle never seemed to notice and just gained more power through maneuvers. Even more importantly, the Sickle didn't have any trouble staying up when the wind would die down below 10 mph. I couldn't climb as high, but I wasn't forced to just figure eight and conserve altitude, I could continue doing aerobatics with confidence. Truly the best of all worlds!

!!Aerobatics
@909380:Cranking up for a roll.
@909381:I was cuttin' loose at this point!!

The Sickle inspired a lot of confidence right away, so it wasn't long before I was wringing it out. Rolls are very brisk and axial and I estimated the roll rate at 2-3 per second. Speed retention was excellent and I was able to do 3-4 rolls going vertical from a shallow dive before running out of headway. The first loop I tried resulted in the nose popping up and the Sickle literally falling backwards a foot or so. I knew the cause for that and landed immediately. Fortunately my Eclipse 7 allowed me to adjust the elevator response independently of the aileron travel. I turned the elevator throws down to 1/4" either way and re-launched.

This time I had gotten well into the loop before it fell off to one side. Next I picked up some speed and applied only a slight amount of elevator. I was rewarded with a HUGE powerful loop. WooHoo!! I might cut down on the elevator throw more in the future to see if I can get the loops even tighter. Inverted flight was not much, which I expected. If I did a half loop and retained a lot of speed I was able to hold inverted for a short time with full down. I haven't seen a swept back wing yet that could fly inverted very well.

<big>Final consensus... I was definitely pleased with the Sickle in every way. </big>

!!Is This For a Beginner?
While building the Sickle would be a snap for the beginner, especially with the great instructions, flying it would not be! RCWorks stated at the beginning of the instructions that the Sickle was not a good first wing. Having flown it, I completely agree. The responsiveness and roll rate that so pleased me would be an uncontrollable disaster for the new flyer. A beginner would be hard pressed to hurt the Sickle, but walking down the slope to retrieve it every 10 seconds would discourage even the most determined newbie. However, for a second wing or the foamy slope veteran, hang onto your hats, the Sickle was a load of fun!

!!Flight Video
@909382:Hovering above the slope crest after racing toward the face and whipping around.

Here's some heart-pounding action filmed by my favorite camera person (my wife)! She also took the stills in this article which wasn't easy. The Sickle was a fast and nimble plane that was hard to follow!

+909383:The Sickle gets put through its paces.

!Conclusion
Putting a Sickle in your slope fleet is a no brainer. Unless you are a total beginner, this plane has everything going for it. Super low price, quick and easy build with excellent instructions, absolute minimum gear requirements, near indestructibility, and last but not least, great flying characteristics. The Sickle would make a great inexpensive way to get your friends together for some slope combat. Either way, flying solo or knocking your friends out of the sky, the Sickle will put a big smile on your face for many reasons. I highly recommend it.