• Wing Span: 38 in (97 cm)
• Wing Area: 585 sq in (3774 cm²)
• Length: 34 in (86 cm)
• Weight: 2.9 lbs (1.3 kg)
• Engine: .15 - .40 2 - cycle
  (2.5 cc - 6.5 cc 2 - cycle)
• 3 Servos required

The Diamond Dust is one of the recent product offerings from Diamond Dust RC. The product line is categorized by extremely flexible performance envelope, high tech design approach, and utilization of space age construction materials. The Diamond Dust is no exception and the sleek, delta shaped flying wing has an extraordinary speed envelope in a very cost effective format. What prompted the purchase of this airplane was an article in R/C Report 1996, about "the need for speed." A Diamond Dust Delta, slightly modified with a shroud, powered by an OS . 46 VR DF, managed to break 200 mph.

The construction of the Diamond Dust involves the use of kevlar, carbon fiber, fiber glass, balsa and plywood. The materials used should by no means intimidate someone unaccustomed to them, since it is very simple in construction and no other glues than thick and thin C/A are required. Although it can be built very quickly for use for R/C sport, combat or speed events, the Diamond Dust is not recommended for beginners, but is for more seasoned pilots. It features laser cut parts, AutoCAD generated plans, totally interlocking fuselage construction, diamond shaped, symmetrical airfoil, and easy to follow instructions. The cut parts came nicely packed in a small box. The instructions include some photo illustrations and are complete. The plans are one sheet printed on one side and a complete hardware is included with this kit.

The construction method consists of assembling the complete airframe with rubber bands prior to application of any adhesive, so checking for alignment and fit is actually completed before the gluing begins. After all joints are secured, the rubber bands are simply removed and the airframe is done. The building time was well below three (3) hours. Sanding and covering took six (6) hours. Installation of hardware, radio component, engine and tank took another three (3) hours. Although, time was taken to ensure that everything was correct the first time, this airplane took less time than any ARC and some ARFs.

The recommended engine size is .15 - .40 but a Rossi .45 was mounted on the Diamond Dust. For throttle control, a Futaba S-3003 was used and since the ultimate goal was speed, the elevons are controlled by high torque BB servos. No rudder is required, nor is it recommended. A Futaba 8UAP was used with a flat 250 mAh battery pack to save some weight. The throws were set slightly higher than that specified on the plans based on a recommendation. If a dual rate system is used, the low rate throws should be set to the recommended throws and high rate throws should be set to about 200% of the low rates. The use of 40-50% exponential, both on high and low rates is a necessity in order to feel comfortable with the higher speeds achieved.

Due to the choice of engine, the finished plane came out very nose heavy even with the battery moved all the way to the rear so reluctantly, 2 ounces of weight was added to the rear. Planning ahead will result in the C.G. being on the mark without added ballast. Of equal importance to the C.G., lateral balance must be ensured to avoid trim changes going from high to low speed. The thrust angle of the engine was set to 0-0 and the wingtip incidences at exactly 0-0. These checks must no be omitted.

The first flight, after a substantial preflight check was conducted in 32° F. weather. The winter in Michigan has been relatively warm and so the opportunity to test the Diamond Dust was taken at the end of January. No willing volunteers were around for the launch, so a cradle-type combat launch was utilized. The plane flew like it was on rails, and absolutely no trim changes were required. The engine was a little rich, since the approach was to gradually push the envelope during several flights. For subsequent flights, the Diamond Dust was hand launched. The delta shaped wing proved to be extremely stable. Props used, ranged from 10-5 on initial flight, to 8-8 and 9-8, all APCs. Maximum speed was achieved with an 8-8 and the best acceleration was a 10-5. The best overall prop was found to be an 9-8. The landings on these flights were at trainer speeds, very easy since the model has a very gentle glide slope and requiring flaring dead-stick a few inches off the ground.

A vertical U-shaped pattern is used to ultimately unload the engine in high speed dives, and the distance from the flight station to the turnaround point demands using contrasting colors on top and bottom. The Diamond Dust feels more stable at faster speeds. This model was built completely stock the no tendency to flutter has been experienced. To date, there is no firm speed measurement, but a conservative estimate is around/above 150 MPH. The Rossi is more powerful but there is no aerodynamic shroud for the exhaust system. Roll rate is not measurable but a guess would be 3-4 rolls per second initially, just a blur, at the expense of a reduction in speed. Loops can be very tight or as large as desired. Since the thrust to weight ratio on an 9-8 APC is around 2.5 to 1, there is pretty good vertical acceleration from a standing start. Low speed flying at high angle of attack is uneventful due to the yaw and roll stability of the delta swept wing, and a diamond shaped symmetrical airfoil. Although not designed for aerobatics, the Diamond Dust can spin and even flatspin with some coaxing. Rolling circles are very gentle at reduced power, and quick four point rolls are within its performance envelope. Low speed, high angle turns cause a slide that looks funny but are very comforting. Hovering and 3-D type maneuvers such as elevator and torque rolls are well within the flight envelope even with the absence of a rudder, but are far from the intentions of the design.

There have been recent developments in design improvements and material selections which significantly contribute to enhanced flight envelopes. The Diamond Dust RC products are, with the Diamond Dust, defining another milestone in terms of radio controlled offerings. Some construction methods, such as kevlar wrapped leading edge and carbon fiber main spar, are ideas that will be brought to other projects. The very short building time is noteworthy, and the stability and rigidity of the airframe is exceptional. The Rossi .45 is by no means a necessity since the Diamond Dust can fly well with .15-.20 size engine but the airframe can handle the load without reinforcements and the larger engine fills the "need for speed."