Personal/Corporate, Products

A Blade Slap From The Past

By Paolo Magnani, reporting from Ovada, Italy | October 1, 2004
Send Feedback

In a manner of speaking, the story of the Dragon very-light helicopter dates back to the third century before Christ, when Berenice Pancrisia was founded by Ptolemy II in Eastern Africa near the Red Sea. The city, well known for gold resources, was slowly abandoned following the collapse of the Egyptian Empire and the site was eventually swallowed up in the hot sand of the desert.

On February 1989 Angelo and Alfredo Castiglioni, twin brothers and world famous archaeologists, found, with a radar and a GPS mounted on a helicopter, the exact place where the town lay buried under the sand. The twins discovered the importance of a simple, cheap and affordable helicopter, so they decided to build one of their own.

The original plan was to develop an ultra light helicopter, or ULM, for private use. However, the aircraft was ultimately built following the "very light rotorcraft" (VLR) rules. Under Italian aeronautical laws, a VLR helicopter can generate profit whereas a ULM cannot--so the Dragon Fly 333 was born.


The helicopter had a modular titanium tubular frame, a cabin easily disassembled by unscrewing four bolts and two electrical connectors, a two-stroke engine and the dynamic systems built by former Agusta's engineers.

The blades folded, allowing the Dragon Fly to put on a trailer and transport by car. A standard 20-ft. container could accommodate four disassembled helicopters and it was very easy to reassemble them, ready to fly again. Another clever idea was a truck used as a helipad--the helicopter could safely land on a stabilized platform behind the truck's cab.

On June '96 I was asked to attend the 333 certification ceremony near Cucciago (northwestern Italy). Such a flexible helicopter can attract--they said--a lot of potential customers all over the world. Some people thought the aircraft could compete directly with the Robinson R22 in performance and price. But like a mirage in the desert, reality turned out to be another story.

The firm quickly sold roughly 80 helicopters in Abu Dhabi, Australia, Belgium, China, Czech Republic, France, Germany, Italy, New Zealand, Portugal and Turkey. Then disaster struck in the form of reliability problems with the aircraft's two-stroke engine. Eventually the company was closed and sold by auction.

When things appeared be to be at their absolute worst, Adelbert Frommer, a manager heading a team of German investors, bought the entire inventory but decided to leave the facilities in Italy.

In 2001, the new company, now called "DF-Helicopters," settled in Ovada near Genoa in a better facility with more hangar space and with a certified heliport.

Frommer took over as managing director and appointed Guido Polidoro as project manager. Polidoro had the task of solving all the engine reliability problems and enhancing the performance of the 333. Polidoro, a highly skilled technician, not only solved all the problems but also built a completely new helicopter: the Dragon 334 GP--with GP standing for Guido Polidoro.

The helicopter now has a semi-rigid main rotor with two composite blades running at 520 rpm. The tail rotor has been redesigned with two composite blades having a twisted profile to counterbalance the loss of lift at high angles of attack.

The helicopter has a welded titanium frame and the fuselage is a carbon fiber composite structure reinforced with epoxy resin. The tail boom is made of aluminium alloy.

The new engine, a four-cylinder four-stroke turbocharged Rotax 914, generates 115 hp. A new engine mounting has been designed to fit the Rotax to the existing titanium frame. The piston heads are cooled by water, the cylinders by air. An air intake has been designed on the top of the fuselage to improve the forced ventilation system blowing a steady airflow--1,800 ft./min.--on the engine in every flight condition. The Dragon 334 GP can perform extended hovering without temperature problems with only the fuel as a limit.

Another example showing Polidoro's ability is the transmission upgrade. The engine compartment isn't roomy, so it was difficult to design a system including a pulley with three polymer belts, a centrifugal clutch, a fan and the main gearbox. To save space, the centrifugal clutch and the aviation-grade sprague clutch has been integrated with the pulley. The tension of the driving belts can be modified to change the position of the new engine mounting.

DF-Helicopters gave Rotor & Wing the opportunity to see the Dragon 334 GP in the final configuration during the flight test program to prove the helicopter's handling quality.

During the first flight tests the rotorcraft showed great stability and exceptional performances compared to the 333 because of the high efficiency of the new blades. The engine also showed good performance, running for more than 500 hr. without problems.

When I visited the company in May, Polidoro and Gianni Lavagna, the production manager, showed me the new carbon fiber cabin with its redesigned windshield--there is no obstruction except the doorframes and the small instrument panel. The new cabin has a streamlined shape with superb visibility and less drag.

There are still about twenty old models scattered around the world. These helicopters can be totally retrofitted to the new standard, although the process is quite expansive.

"You must consider that we have drawn about 600 new pieces," Polidoro said. "The helicopter's frame, the fuel tank and the skids are the only pieces the old and the new project have in common!"

The Ovada factory does not have a flight training facility, so pilot training for purchasers of the 334 GP will be conducted at the ULM Flying School, about 40 km. from the factory. However, both the aircraft and instructors will provided by DF Helicopters. Training will be conducted under Italian regulations on recreational and sports flights rather than those established in JAR Ops 3, Frommer said.

Frommer foresees a bright future for his company, with plans for a preproduction of 15 helicopters followed by a production run of 50 units in the begining. The first helicopters will be in the ULM version. but the production aircraft will be certified as VLR.

Frommer is seriously intending to open, as soon as possible, a branch office in North America. Only the future will reveal if he will be the European equivalent of Frank Robinson.

The Dragon 334GP (Technical data)

Dimensions, External

Main rotor diameter 6,70 m (21 ft 11{3/4} in)
Length overall, rotors turning 7,89 m (25 ft 9 {1/2} in)
Height to top of rotor head 2.36 m (7 ft 9 in)

Dimensions, Internal

Cabin: Length 1.11 m (3 ft 7 {3/4} in)
Max width 1.15 m (3 ft 9 {1/4} in)
Max height 1.13 m (3 ft 8 {1/2} in)


Main rotor disc 35.21 m {2} (379.0 sq ft)

Weights and Loadings

Weight empty, standard 260 kg (573 lb)
T-O weight: normal 450 kg (992 lb)
max 550 kg (1,212 lb)


(two crew, half fuel)
Max level speed at S/L 82 kt (153 km/h; 95 mph)
Cruising speed at S/L 70 kt (130 km//h; 81 mph)
Max rate of climb at S/L 381 m (1,250 ft)/min
Service ceiling 3,050 m (10,000 ft)
Hovering ceiling: IGE 2,050 m (6,720 ft)
OGE 1,450 m (4,760 ft)
Max range 210 n miles (390 km ; 2422 miles)
Endurance 3 h


12 V electrical system with engine-driven 75 AH generator and 12 V 19 Ah battery.


Usable fuel capacity 57 litres (15 US gallons; 12.5 Imp gallons).


Medevac and fire fighting kits and external load hook (under development in 1997), emergency floats and skis under development.

Aircraft use

Training (civil and military), traffic observation and border patrol, "flying doctor" service, transplant organ transportation, light aerial work, civil protection, public transportation, alert diffusion, aerial pictures, power-line patrols, pollution analysis, crop spraying, private operations.

Estimated price: $12,5000

Receive the latest rotorcraft news right to your inbox