by Mike Feeney
From my recollections, the Call Aircraft Company (CallAir) was established in 1939 by Reuel Call at Afton, Wyoming, to build a touring aircraft that he had designed. WWII intervened and they carried out repair contracts for the duration. After the war they did produce several hundred of the “A” series, a tidy low-wing cabin aircraft, but realised that they would be unable to compete with the likes of Piper and Cessna so the company focused on the agricultural aircraft market.
In 1954, CallAir designed the A-4, one of the USA’s early purpose-built spray aircraft. Whilst a moderately successful type, the company ran into financial problems and was sold to InterMountain Manufacturing (IMCO). I think that the “A” series of cabin aircraft used the 125 or 135 bhp Continental engine. Already evident is the non-cantilever, strut-braced, wing configuration that became so familiar on the A-9 and the Piper PA-25 Pawnee.
The A-4 and A-7 were improved and re-engined to become the A-9 CallAir using the now classic and most sensible configuration for an ag-aircraft…low-wing with a tractor engine with the spray tank and cockpit raised and rearward. Production of the A-9 commenced in 1963 with 25 being imported into Australia by the distributor, Aerial Agriculture of Bankstown, NSW.
The A-9 has a steel-tube fuselage covered by metal panels forward and dacron fabric to the rear. The wings have wooden main-spars with alloy ribs with dacron covering. The cockpit has a roll-over cage and wire-cutters are fitted to the undercarriage legs and the windscreen. The fibreglass spray tank holds 170 US gallons.
The basic specs for the A-9 are:
- Engine: 235 bhp Lycoming O-540. (later variants used the 300 bhp injected IO-540).
- Wingspan: 35 ft, wing area 182 square feet, length: 24 ft.
- Empty weight: About 1,700 lb. Max. weight: 3,000 lb.
- Cruise speed with load: At 75% power about 90 knots when fitted with rotary atomizers or nozzles.
Whilst I sprayed extensively in the very similar PA-25 Pawnee, I never used the A-9 on ag-work. I logged many hours glider towing in the A-9 out of Gawler, near Adelaide, Australia. We also used a Pawnee and I did not notice any performance difference between them. Both would tow a two-seat K-13 to 2,000 feet and get back onto the ground in about five minutes. I really liked the A-9. It was lively and responsive and comfortable to sit in for a few hours of towing on a busy day.
The B-1 story is of interest to us in New Zealand because it was disliked by many pilots. The B-1 was essentially a scaled-up A-9. It was considerably larger (wingspan 44 ft. 8 inches, length 30 ft.) and a much heavier aircraft with a hopper capacity nearly double that of the A-9. They fitted the 400 BHP opposed eight-cylinder Lycoming IO-720 which was, before fixes were made, a horrible engine. New Zealand operators discovered this with their earlier Fletcher FU-24-950 models which suffered many engine problems and complete failures. Of the 36 B-1s produced, eight came to New Zealand.
I never flew one and I know for sure that some pilots were most reluctant to fly them on aerial topdressing operations. I was unable to find any reliable weight data for the B-1 other than a payload figure of 1,500 lbs, which does not sound correct for such a large spray tank/hopper size. I recall carting nearly 1,300 lbs of spray-mix in the 235 BHP Pawnee from a good airstrip. My guess is that the B-1 had an empty weight of about 3,000 lbs. Add the pilot (180 lb) and fuel for 1.5 hours (200 lbs), plus a load of 2,000 lbs of fertiliser and we get 5,380 lbs. That is about the same as a 400 BHP FU-24 or a DHC-2 Beaver.
I did hear that the B-1 was a ‘ground-lover’ on take-off and had poor climb performance. I also heard that its undercarriage was not up to the large numbers of take-offs from our often rough airstrips. I hazily recall hearing, or reading, something about the engine cowl shape creating adverse aerodynamic effects at high power…down-forces which did not help matters as airspeed increased. I can’t find any written reference to this effect, but it has stuck in my memory over many decades. But, the fact is that the B-1 was principally designed for aerial spraying operations from reasonably good airstrips and probably did a good job of that.
In the CallAir Museum, which is co-located with the Afton Civic Centre, I saw a yellow B-1A hanging from the ceiling. It had a 450 BHP Pratt & Whitney R-985 radial fitted and a three-blade propeller. To my eye, it looks a lot nicer than the version with the flat-eight IO-720.
My opinion is that some New Zealand operators tried to operate the aircraft with excessive payloads which did not suit, relative to overseas practice, our short airstrips. Studying a photograph of the B-1, I note the long and wide upper fuselage and engine cowling. In the flying attitude, it does present a large surface area which could well have generated a considerable down force. I wonder also about the deck angle the B-1 sits at in the three-point attitude. The undercarriage is quite short which results in an angle-of-attack several degrees less than that required to generate maximum lift at the take-off end of the airstrip. And, unlike an FU-24, at high weight it is not possible to rotate a taildragger to a high angle of attack, thus requiring a higher airspeed to be attained for a clean lift-off. On short New Zealand airstrips, I can visualise the problem, particularly as ground effect was suddenly removed as one fell off the end of the strip into clear space. Also, as the aircraft began to roll after loading, the undercarriage would tend to spread, further reducing the AoA.
One wonders whether vortex generators on the top cowl may have improved matters. Certainly the B-1A, with its uncowled P & W R-985 radial breaking up the airflow, would not have had that down-force problem; in my estimation.
Several of the New Zealand B-1s suffered accidents. In 2012, on the Flight Safety Foundation’s www.flightsafety.org Aviation Safety Network’s database, I found 17 accidents involving the CallAir B-1. Of these only three were in the USA, one of which was fatal. All the remainder listed occurred in New Zealand. So, it may be fairly said that the type’s operational record under our operational conditions was dismal indeed. I have to wonder just how much homework was done by those operators who purchased the B-1 with the Lycoming IO-720 engine. It is somewhat of a mystery to me, as the involved operators were experienced men and not fools.
Mike Feeney of Hamilton, New Zealand is a retired professional ag-pilot and a long-time aviation journalist, technical and air safety writer. email@example.com