Background

I had been looking for a pre-built (ARF) model that I could use to practice thermal hunting. My only experience to date had been with my trainer, a Goldberg Mirage (RIP), and the Trick R/C Zagi 400. I also wanted the model to be easy to fly, fast, and aerobatic for general sport flying. I wanted an ARF primarily so that I would have something that could be flown as often as my Zagi without the fear of damage after spending months in the shop! This would allow me to get plenty of glider stick time before I finish up my electric-conversion of the Great Planes 100" Spirit, which is currently about 80% completed (after months in the shop!)

I started looking at a few models that seemed to fit the requirements.  I also posted online at the E Zone discussion groups.  I originally looked at the Kyosho Soarus Sports, but decided against it based on the plastic flying surfaces - I preferred wood, in case repair was needed at a later time.  After a couple of weeks' research, I ordered the Crazee from Dymond Model Sports.

I had most of the equipment I would need, but a new model is always a good excuse to buy more equipment!  I thought about using Hitec HS-60's in the wings and for the tail surfaces. These tiny servos have been doing a great job in my Kyosho F16. After consulting the great reference page at Hitec RCD's web site, I realized that the HS-81's are only a fraction of an ounce heavier, but have much more torque. I have used many of the older HS-80's in the past with great success, so I ordered four of the replacement model, the HS81. I have been led to believe this airframe is very fast in a dive, so I figured the 81's will serve me well.  I also picked up a new Jeti 500 speed controller (ESC), which has battery eliminator circuit (BEC) and brake (which can be disabled).  An older model Jeti 35 has served me well in both the Mirage, and then my Kyosho F16.

Kit

I received the Crazee just two days after ordering. The 36" x 11" x 4" box was enclosed in brown cardboard shipping box. This is the first kit I've ever had delivered to my home, and it was a nice surprise to find that there was no damage to the box.  The only disappointment was that the canopy arrived broken. I am unsure how this happened, as all parts were well protected in transit. A quick call to Dymond, however, and a new canopy was on its way.

The first item of note (after you see the wonderful bright pink covering) is that there are so few parts to assemble. This kit is provided complete, requiring only the addition of servos, radio, battery and ESC to fly. The built-up and pre-covered wing panels and tail surfaces are expertly constructed. Even the ailerons, rudder and elevator surfaces are built-up, which was a surprise.

All control surfaces are pre-hinged from both sides with covering material. The fuselage has the motor and mount, push rods and servo tray already installed. The wing halves are provided with dual aileron (micro) servo mount locations in each wing panel, as well as servo wires (that need to be spliced into your servo leads) already in place. These wing panels weighs a mere 3.9oz each; they are joined with two aluminum joiners and simply bolted to the fuselage.  The tail surfaces are installed by simply threading the two bolts that are pre-installed in the fin through holes in the horizontal stabilizer, then through the fuselage, and held in place with small nuts.  This permits easy disassembly for transportation.  I chose, however, to make the installation of the tail surfaces permanent.  Here, as well on all other metal fittings, I used a drop of Bob Smith Industries IC-2000 Cyanoacrylate (CA) glue to prevent the nuts from working loose.

Construction

One of the capacitors on the motor had a poor solder connection and had broken loose, and I felt that the supplied wires were not well soldered and needed to be replaced. I re-soldered the capacitors, replaced the motor leads with some Dynamite 14ga wire that was sitting around, and attached Deans Ultra connectors (used exclusively on all of my equipment) to both the motor leads and the speed control.

The motor was broken in, without a propeller, for 30 minutes at 2A, and then tested for power. I use an AstroFlight WhattMeter for all my power measurements.  With the supplied 8x4 folding propeller installed and using a peaked 7x1700RC pack, I measured 37 amps and 330 Watts, spinning at 13,500 RPM. A few seconds later, it settled down to a more reasonable 30A, 262W and 12,700 RPM.  My very unscientific 'hang from ceiling-attached fishing scale' thrust measurement showed about 16-18oz thrust. I have a spare Astro 05 motor that I had planned to test at some point. Given these results, however, I chose to fly on the stock motor, at least until it gives up the ghost!

The covering was well applied and fairly tight, but the hot Georgia sun can cause even the best covering job to sag and flutter. I ran my heat gun over all of the surfaces, and the covering quickly shrank to a nice tight fit. Take care, however, not to introduce any warping or twist into the surfaces, especially the built-up control surfaces.

Although I had purchased HS-81 servos for this airplane, when it came time to cut the wires and splice into the supplied extension wires, I had a change of heart.  In my servo drawer were HS-80's that needed new gears, and I just happened to have a few sets of metal gears waiting to be installed.  These servos had been installed in a wing previously, and the plugs had already been removed. I fitted the metal gears, and installed them as aileron servos - first splicing the leads into the pre-installed aileron extension wires, then mounting to the supplied ply plate with GE silicon household adhesive.

Here I encountered a small problem - I had received two identical servo cover plates - for proper installation, there should be a 'left' and a 'right'. I had to cut one in half to make a suitable cover, although this is not visible once the supplied covering material is applied over the cover.

I used a set of 4-pin Deans connectors on the aileron extension leads to permit the wing panels to be easily removed from the fuselage. The way I wired the two aileron extensions to one plug means that the wing panels need to be stored and transported together. Most people would probably choose to use two connectors here.  This is no problem, however, and one plug speeds installation of the wings at the flying site.

I tested the fit of the wings by inserting the two aluminum joiners into one wing panel. The slots for these joiners were very stiff, and I needed to provide a good tap with a hammer to seat them correctly. The other panel slid on and off with a fair (but not excessive) amount of effort. Unfortunately, I did not realize during this process that about 1/2" of the wing tip had been damaged while inserting the joiners into the first wing panel. I was able to straighten this out by hand, however, and the iron smoothed out any remaining wrinkles. Care should be taken with these wings; the tips are quite thin and fragile.

Another problem was encountered when installing the tail surfaces.  The joiner rod that connects the elevator halves is about 1/8" behind the TE of the horizontal stab - this is needed for clearance when full up or down elevator is applied. As a result, however, this rod causes the rudder to bind when applying right stick. I needed to remove some material from the rudder at this point of contact. Be very careful not to remove too much material - the leading-edge structure of the rudder is visible in the photograph - you do not want to weaken this any more than necessary.  On reflection, perhaps the covering could be carefully removed, and a triangular fillet installed at this point to help strengthen this area.  I made the modification, and used some scrap covering material to cover my work.  The binding problem was eliminated.

I used two of the new HS-81 servos for the rudder and elevator controls.  The pre-installed servo tray is only good for larger (full-size) servos.  There is, however, a plywood tray provided for micro servo use. This was installed over the plastic tray, with both CA and a couple of screws.  The control surfaces were attached with the provided plastic clevises - these were quite secure, but for added safety I wrapped each with 1/4" length of fuel-line tubing as holders.

The Futaba 127 receiver was wrapped in foam and placed onto the battery tray. I found that the CG was right on with the battery inserted at an angle.  I added a small angled wedge of balsa to the front of the battery tray. This permits the battery to be retained with a strip of Velcro hook and loop fastener. This holds the battery firmly in flight, and (as I discovered) survives even a harsh landing. The Jeti 500 ESC is simply placed in the area behind the motor - the sturdy power wires prevent it from moving around too much. The 'arming' power switch was installed inside the canopy, which is removable with a quick flip of it's retaining pin.

The control throws were set up with dual rates, the high being a little more throw than per instructions, and low rate about 60% of these settings. Subtrims were used to center all surfaces, and I set up a spoileron/camber mix - a three position switch allows for both pre-set spoilers, or aileron camber control with the channel-7 mix knob. What can I say, I like to play with the mixers on my 8UAF!

You will note the silver canopy in the assembled picture above - the easy assembly meant that I was ready to fly in just a few hours - the day before the replacement canopy arrived! So I could get out and fly, I taped the old canopy together from the inside, and applied chrome Monokote to the outside to cover the cracks.

Flying

First flight was quite impressive. On 7x1700RC cells, it climbed out well from a casual power-off toss (a habit from launching my Zagi's!). A few gentle circuits were flown to trim out for level flight.  The Crazee required one click of down and a couple of clicks of right, although the wind made it difficult to fly 'hands off'. It certainly slows down well enough, flying on about 1/3 throttle it continued straight ahead at much reduced airspeed. I found it to be very responsive to control inputs, especially in turns, although I used high rates on the elevator. I let it build up some speed and tried a loop - nice and tall, not very round, but that is more a result of pilot inexperience! A roll with the ailerons on high-rates took about 1.5 seconds, although it did lose a lot of altitude during the inverted phase. I guess this means I could adjust the CG some, but I'll wait until I really get comfortable with it first.

I decided to land after 4 minutes of powered flight, to check everything over and ensure I wouldn't have to deal with a dead-stick situation on my first flight. Although it feels heavy at 44oz, I soon found that it's a floater. I had to make a 360 degree turn on final to lose a little more altitude, and then line it up for landing. Although I had forgotten to turn off aileron high-rate, the controls at low altitude and airspeed were gentle and smooth. Once lined up for landing, it settled nicely onto the grass.

All nuts, bolts and surfaces checked out fine, and the flight was declared a success, at 4.5 minutes. A second flight was attempted on 8x2000RC cells. This flight was a little more exciting, from the very beginning. The launch was superb, it climbed out at about 45 degrees. After only about 30 seconds or so, however, there was a loud bang, and something fluttered down from the sky. I seemed to have full control, and although I had lost motor power, the landing was uneventful. Upon inspection, I found that the fluttering object was in fact the canopy, which was later recovered across the field. The cause of the bang was the prop coming apart! The force exerted on the prop blade pins was too much at those RPM's, and the pins had actually bent and torn themselves out of the plastic hub. One blade was missing - probably in the next county! The violent loss of a blade, and resulting vibration, had torn the motor out of it's mount, pulled the fuse from the connector, and thrown off the canopy.

Inspection on the bench revealed very little damage - the motor mount was easily re-shaped, and held in place by screwing into new holes. The prop was a loss, but I had ordered a couple of Graupner CAM folding props from Kirk at New Creations, and they arrived in time for the next club meeting.

I have flown the Crazee several times since that first day, and have enjoyed each flight a great deal. I tested a 9x5 CAM prop, and it does provide stunning performance, but the motor is not likely to survive many flights under that kind of load. The CAM 8x4.5, however, is very good, and does not at all mind the higher RPM's produced with 8x2000RC cells. I have flown in 35MPH gusts, and although it was tricky to gain much ground upwind, the downwind passes were quite impressive, and landing was no problem at all.

I have little soaring experience, so I cannot comment on how well this airplane performs as a thermal sailplane.  I think it is more of a sport flyer, but the large wing area and relatively low wing loading should make it possible to hunt out some good thermals in the hot summer days ahead.  I will comment that I flew one hot Saturday afternoon, and found the nose kept wanting to pitch up, and I needed constant down elevator to prevent it from climbing.  As all trims and surfaces checked out OK, I may have encountered a killer thermal, but I can't be sure.  I will test with an 8 cell pack of 1250 SCR cells, which would make it lighter still.  Be certain to check out my periodic reports on the E Zone discussion groups for more information!

The Crazee has fulfilled my need for a general purpose sport airplane. I highly recommend it!