Super Cubs go to seed

Avatar for Eric DumiganBy Eric Dumigan | March 27, 2019

Estimated reading time 5 minutes, 36 seconds.

For the next five weeks — weather permitting — three General Airspray Ltd. (General Airspray) Piper PA-18 Super Cubs will cover approximately 4,500 hectares of land with Jack Pine and Black Spruce seeds near the Northern Ontario towns of Dryden, Kapuskasing, Kirkland Lake, Elliot Lake, Chapleau and Sudbury. This seeding is completed by General Airspray for its annual winter broadcast tree-seeding program.

General Airspray will use three Piper PA-18 Super Cubs to seed approximately 4,500 hectares of land over the next five weeks. Eric Dumigan Photo

The youngest pilot on the job is 26-year-old Dave Hodgins. This is Hodgin’s first year as an aerial seeder, and he is a third generation pilot at General Airspray, following his father and grandfather. General Airspray, based in Lucan, Ont., was founded in 1962 in St. Thomas, Ont., when Roscoe Hodgins (Dave’s grandfather) and Doug Worgan bought Leavens Brothers’ spraying business.

Dave is also a licensed aircraft maintenance engineer, and along with his father Paul and full-time pilot, Stephen Hogg, they maintain a fleet of four Piper PA-18As, five Grumman G-164 Ag Cats and a Turbo Thrush 510P.  Dave estimates since his grandfather started aerial seeding in 1968 they have seeded about 1.36 million acres.

In Ontario, aerial seeding occurs between February and April. The black seeds are dropped on the snow at a rate of 30,000 to 50,000 seeds per hectare; they warm from the sun and then melt into the snow. As the snow melts, the seeds get buried into the soil the same as if they were released naturally from the cone. The moisture from the melting snow allows the seed to germinate and build a solid root system to grow before the terrain dries with the onset of summer.

The Brohm Seeder, an 80-kilogram seed tank, is mounted in the backseat of the Cub. Eric Dumigan Photo

With a 70 to 75 per cent catch rate, aerial seeding is great for poor soil types or remote sites and allows large areas to be covered in a short period of time. The most typical subject areas are forests or cutovers that have been fire-scarred. As part of the process, cutover areas first need to be scarified by bulldozers and skidders to expose minerals in the soil.

General Airspray uses a Brohm Seeder system that can cover a swath up to 20 metres wide. The designer, Howard Brohm, worked for the department of Lands and Forests in mechanical research in the 1960s. Along with General Airspray’s founders Hodgins and Worgan, he adopted the seeder system to their fixed-wing aircraft.

The system is first calibrated on the ground to ensure proper application rates, then the 80-kilogram seed tank is mounted in the backseat of the Cub and the seeds are fed through a line to the slinger tubes mounted on the belly of the aircraft. A motor spins the four rubber tubes and the seeds are shot out. In the original models the tubes were made of metal, but X-rays showed many of the seeds to be cracked and broken, so they started making them out of rubber. A second motor inside the aircraft runs a transmission that can be controlled by the pilot allowing for different application rates.

Genereal Airspray uses a Brohm Seeder, which has a motor that spins four rubber tubes to shoot the seeds out of the tank. Eric Dumigan Photo

The pilot paints a block of land on an AG-NAV differential GPS navigation system that minimizes gaps or overlapping spray lines. Logging companies will leave mature trees on the blocks of land to protect habitats and help with soil erosion, and the pilots maintain an altitude of 20 to 30 feet above the tallest trees in the block.

On average the Cubs can cover 4.85 hectares per minute. Operations are restricted to visual flight rule conditions with less than 10 to 15 kilometre-per-hour wind speeds. A full tank of seeds can cover 535 hectares (75 kilograms) but the average load is around 200 hectares (28 kilograms.) Most sorties last three to four hours and could involve multiple blocks as far as one hour away from the airport, so fuel calculations are important to ensure there is enough reserve fuel on board for the duration of the flight.

General Airspray Cubs are equipped with a SPOT Tracker and the latest GPS 406 ELT. The SPOT Tracker is a GPS tracking device that uses the Globalstar satellite network that can send messages to forestry personnel as well as letting them track the aircraft’s location on Google Earth. The SPOT Tracker can be used to send an SOS message as well, if needed.

All aircraft carry a winter/summer survival bag in the event of an emergency.

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