The Early Bird “Jenny” is approximately a 2/3 version of the Curtiss JN4-D World ar I Trainer that took part in many firsts in American aviation history (first combat aircraft, first mail airplane, etc).
Of course she is probably best known as the favorite airplane of the barn stormers during the 1920’s. Though similar in appearance to the original, the construction of the Early Bird “Jenny” takes advantage of modern high strength, more durable materials that also speed the building process.
The fuselage is built of strong aircraft 4130 chromoly steel (a proven construction material with several million flying hours in aircraft like Cubs, Taylorcraft, etc.). The wings are built of 6061-T6 aluminum tube spars and pre-stamped aluminum ribs. Standard 2.7 oz. dacron fabric covers the airplane using the Canadian Hipec paint system that eliminates time consuming rib stitching.
The paint scheme, of course, is a personal option (W.W. I trainer, barn stormer, etc.) and is a lot of fun to plan. The wheels (used motorcycle or new wheels from Loehle Aircraft) make for easy ground handling with their built-in brakes, yet they look like the old, original wheels.
The airframe is capable of using a number of different two or 4 stroke engines in the 130-150 lb., 45-65 HP range. The original 46HP Rotax 503 SC in the prototype did a reasonable job of hauling two average sized people here in Colorado at over 5000 feet and burned about 3 1/2 GPH – that engine never missed a lick in over 300 hours (and it is now flying in another “Jenny” ).
If you are really on a budget, there are some good used engines out there for as little as $500 that will keep your total cost down to about $5000 ready to fly. On the other hand, a new dual ignition 65HP, water cooled Rotax 582 has a great power to weight ratio. If you want lower fuel consumption (without mixing oil!), and better sound you might want to try a 4-stroke engine in the right power and weight range.
A Rotax 912 is the right size and weight. The Geo Metro may be an option for those willing to take on an engine project. A 60 HP Franklin or some of the newer, lighter weight aircraft engines may work well for those wanting an off the shelf solution.
The empty weight can be kept down to about 420 lbs. if you use a two stroke engine of about 100 – 125 lbs. with electric start, battery, prop, etc and the optional aluminum frame rudder and elevator to give you a full 380 lbs. of useful load. That equates to about a 200-foot take-off roll at sea level (100 foot or less single seat! ). Due to her large wing area, you also have a very good angle of climb for those short fields with 50 foot obstacles all around.
The empty weight will be about 450 lbs. with a four stroke engine and slight airframe modifications can give you full gross weight of 900 lbs. Slow flying where nothing happens very fast is one of the great joys of flying your 2/3 “Jenny”! Like the great old biplanes of the past, you have a bit more time to react compared to the hot, short-coupled designs of today.
Her three axis flight characteristics are pretty well described as “Cub-loke” with a fair amount of rudder available and about a three and a half to four seconds 45 deg – 45 deg roll rate. I’ve flown her for as long as 45 minutes without touching the stick (something that you couldn’t do with an original “Jenny”).
Although her flight speeds are similar to the original, she has a better climb performance due to the improved power to weight ratio. A good climb out and approach speed is in the 45-50 MPH area with about 70 MPH straight and level full throttle and 60-65 MPH at cruise (q 65 HP engine will do a bit better, of course).
She just loves little grass fields and, as mentioned before, she is quite capable of short take-offs and landings. With a roller blade wheel sttached to the tail skid you can happily land and taxi on modern, larger hard surface airports but be ready to deal with a lot of attention and interest in your unique litle “Jenny” – Boy does she bring out the smiles on people’s faces!
The aircraft is a 67% scale replica of the First World War Curtiss JN-4 Jenny. It features a strut-braced biplane layout, a two-seats-in-tandem open cockpit, fixed conventional landing gear and a single engine in tractor configuration.
At the time the kit was first made available the aircraft could be constructed as a US FAR 103 Ultralight Vehicles exemption two-seat trainer or as an amateur-built aircraft.
The Jenny is made from a mix of steel and aluminum tubing, with some wooden parts and its flying surfaces covered with dopedaircraft fabric. Its 27.50 ft (8.4 m) span wing has a wing area of 175.0 sq ft (16.26 m2) and the cockpit width is 24 in (61 cm). The acceptable power range is 46 to 65 hp (34 to 48 kW) and the standard engines used are the 50 hp (37 kW) Rotax 503, 64 hp (48 kW) Rotax 532, 64 hp (48 kW) Rotax 582, 74 hp (55 kW) Rotax 618 two-stroke engines and the 62 hp (46 kW) Geo Metro-based fuel injected Raven 1000 UL three cylinder, inline, liquid-cooled, four stroke automotive conversion powerplant.
The aircraft has a typical empty weight of 419 lb (190 kg) and a gross weight of 800 lb (360 kg), giving a useful load of 381 lb (173 kg). With full fuel of 9 U.S. gallons (34 L; 7.5 imp gal) the payload for pilot, passenger and baggage is 327 lb (148 kg).
Length: 18 ft 4 in (5.59 m)
Wingspan: 27 ft 6 in (8.38 m)
Wing area: 175.0 sq ft (16.26 m2)
Empty weight: 419 lb (190 kg)
Gross weight: 800 lb (363 kg)
Fuel capacity: 9 U.S. gallons (34 L; 7.5 imp gal)
Powerplant: 1 × Rotax 503 twin cylinder, inline, air-cooled, two stroke aircraft engine, 50 hp (37 kW)
Propellers: 2-bladed wooden
Maximum speed: 70 mph (113 km/h; 61 kn)
Cruise speed: 65 mph (105 km/h; 56 kn)
Stall speed: 35 mph (56 km/h; 30 kn)
Range: 130 mi (113 nmi; 209 km)
Service ceiling: 14,000 ft (4,300 m)
Rate of climb: 800 ft/min (4.1 m/s)
Wing loading: 4.6 lb/sq ft (22 kg/m2)