J-5DC "Crane Fly" Prototype

 

This aircraft was originally built as a J-5 Marco motorglider by Jaroslav Janowski, Lodz, Poland.  It was equipped with an Italian KFM 107 ER.  Unfortunately, this small 30 HP engine only allowed the airplane to climb at about 100 feet per minute and the reduction drive belts had a tendency to become loose, stopping power from going to the propeller.  I am modernizing the avionics, installing a ballistic recovery system (BRS), and installing a Hirth F-23 fuel injected engine to improve the rate of climb performance.  Because of the increased engine weight and size, a complete redesign of the engine support, exhaust system, and drive system was necessary.   Following are the specifications for the aircraft with the Hirth F-23 engine.  The numbers with the "~" are approximate based on calculations (not flight tested yet).

 

DIMENSIONS

Wing Span........................................................................... 26.5 ft

Length.................................................................................. 15.4 ft

Height.................................................................................... 4.1 ft

Empty Weight.................................................................. ~420 lbs

TOGW............................................................................... 640 lbs

Tank Capacity............................................................... 10 US Gal

 

ENGINE  -  Hirth F-23 Fuel Injected

Power.................................................................................. 50 HP

Weight................................................................................. 90 lbs

Displacement..................................................................... 521 cc

Cylinders..................................................................................... 2

Cycle....................................................................... Otto, 2 Stroke

Fuel........................................................ Premix (50:1) 91 Octane

 

PERFORMANCE

Stall Speed..................................................................... ~40 KIAS

Cruise Speed............................................................... 100 KIAS

Vne................................................................................. 120 KIAS

Fuel Consumption.......................................................... 1.8 gph

Range.......................................................... 400 nmi (w/ reserve)

Glide Ratio (L/D)..................................................................... ~20

Climb.............................................................................. ~700 fpm

Takeoff / Landing Distance.................................................. 600 ft

Load Factors...........................................................     +6 / -3 g’s