Midwest Microlights HM-81 Tomcat Tourer / The Baron

Single-seat single-engined high-wing monoplane with additional dihedral wings; uncon-ventional three-axis control. main wing has unswept leading and trailing edges, and constant chord; no tall, canard wing. Pitch control by fully flying canard; yaw/roll control by control surfaces on dihedral wings; control inputs through stick for pitch/yaw/roll. Main wing braced from below by dihedral wings. Wing profile; double-surface. Undercarriage has three wheels in tricycle formation; rubber suspension on main wheels. Push-right go-right nosewheel steering independent from yaw control. No brakes. Aluminium-tube framework, without pod. Engine mounted below main wing driving pusher propeller. Tubing in 6061T6 aluminium, anodized. Stainless-steel cables. Dacron wing covering.

Robin Haynes, founder and president of the Waspair Corporation which originally produced the Tomcat, designed this unique machine at the end of 1979. It only became the Tomcat after a succession of names, the first production models having been sold under the name The Baron.

At Oshkosh in 1981 the HM-81 won the EAA prize for the most outstanding new design. The aerodynamic configuration of this machine is very unusual and warrants some supplementary explanation. The Tomcat is made up of three lifting elements: the main wing (67% of the total lift), the two inclined structural wings angled at 45O and with 15O sweepback, (18% of the lift) and the canard (15% of the total lift). The main wing is fixed and devoid of control surfaces, while the inclined wings, Which he called dihedral wings, are two fixed surfaces carrying elevons, like a V-tail. The canard angle of attack can be altered to control pitch, all control being by a single stick which acts as a mixer on the elevons and the canard.

At the beginning of 1982, Waspair Cor-poration offered the standard version of the Tomcat fitted with the twin cylinder 430D 30hp engine and direct drive; with the 430R and 2/1 reduction drive, the machine was called the Tomcat Sport. However, by the end of 1982, the latter had become the standard version. Also appearing at the beginning of 1982 was a Tourer version for the heavier pilot with a heavy-duty airframe and the Cuyuna 430R. It is this model on which the company is now concentrating and at the Sun 'n' Fun in Lakeland, in March 1983, the maker was marketing it as the standard version. In kit form it costs $4695 and pre-built it costs an extra $1150.

Engine: Cuyuna 430R, 30 hp at 5500 rpm.
Propeller diameter and pitch 54 x 36 inch, 1.37 x 0. 91 m.
V-belt reduction, ratio 2.0/1.
Max static thrust 250 lb, 113 kg.
Power per unit area 0.17 hp/sq.ft, 1.8hp/sq.m.
Fuel capacity 5.0 US gal, 4.2 Imp gal, 18.9 litre.
Length overall 12.0 ft, 3.66 m.
Height overall 10.0ft, 3.05m.
Wing span 30.0ft, 9.14m.
Chord at root 4.0ft, 1.22 m.
Chord at tip 3.0 ft, 0.91 m.
Main-wing dihedral 0 deg.
Main- wing sweepback 0 deg.
Canard span 8.0ft, 2.43m.
Canard chord 3.0ft, 0.91m.
Total wing area 175 sq.ft, 16.3sq.m.
Main wing area 125 sq.ft, 11.6 sq.m.
Canard area 25 sq.ft, 2.3 sq.m.
Total dihedral-wing area 25 sq.ft, 2.3 sq.m.
Main-wing aspect ratio 7.2/1.
Wheelbase 7.0ft, 2.13 m.
Nosewheel diameter overall 10 inch, 25 cm.
Main wheels diameter overall 10 inch, 25 cm.
Optional floats, length 11.0 sq.ft, 3.35 m.
Optional skis, length 3.0 ft, 0.91 m.
Empty weight 235 lb, 107 kg.
Max take-off weight 595 lb, 270 kg.
Payload 360 lb, 163 kg .
Max wing loading 3.40 lb/sq.ft, 16.6 kg/sq.m.
Max power loading 19.8 lb/hp, 9.0kg/hp.
Load factors +6.0, -4.0 design; +8.0, -6.0 ulti-mate.
Max level speed 60 mph, 97 kph.
Never exceed speed 65 mph, 105 kph.
Max cruising speed 45 mph, 72 kph.
Economic cruising speed 40mph, 64kph.
Stalling speed 27 mph, 43 kph.
Max climb rate at sea level 800 ft/min, 4.1 m/s.
Min sink rate 250 ft/min at 30 mph, 1.3 m/s at 48 kph.
Best glide ratio with power off 8/1 at 30 mph, 48 kph.
Take-off distance 90 ft, 27 m.
Landing distance 125 ft, 38 m.
Service ceiling 15,000 ft, 4570 m.
Range at average cruising speed 125 mile, 201 km.