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Aviation History
1962
1962 - 1184.PDF
92 FLIGHT International, 19 July 1962 By Mark Lambert: Nos 162 and 163 of the serk BOLKOW 207 (On* Lycoming O-360 giving 180 h.p.) Span, 35ft 6tn length 27ft 3in; wing area, I66sq ft; empty weight, 1.5801b; fuel capacity, 42 Imp gal; gross weight, 2,6601b; wing loading, I6lb/sq ft; power loading, I4.7lb/h.p. Performance Maximum speed, 158 m.p.h.; cruising speed, 146 m.p.h.; landing speed, 53 m.p.h.; initial climb, 690ft/min; service ceiling, 14,100ft; range at 55 percent power,780 miles; take-off to 50ft, 1.580ft; landing from 50ft, t,51 Oft. Bolkow 207 FOR pulling four people and baggage around at any reasonable speed, 180 h.p. is a fairly small ration of power. The airframe must be reasonably clever if anything attractive is to be made out of such a specification in the way of cruising speed and cabin size. A notable success is the Picchio—and the Comanche 180 is very good as a mass-produced solution. The Bolkow 207, with a fixed tailwheel undercarriage, seems to start off with a good many disadvantages; but when I flew it during the Shackleton sales week end at Sywell I was pleasantly surprised. With four people and full tanks "pulling" 24in and 2,300 r.p.m. at 2,000ft (75 per cent power), it indicated no less than 120kt and was delightful to handle. Detail finish is excellent, there are a great many neat answers to usually tricky problems and the controls bear obvious traces of the work of a master test-pilot or designer—probably both. I have an increasing respect for German design and handling characteristics. British distributors are Flair Aviation Sales Co, Biggin Hill, Kent. For one thing, there was no noticeable control friction. In cruis ing flight I could virtually have used the stick to flick paper pellets at the man in the right-hand seat. Overall feel and forces were excellent, though the forces were scaled for a four-seater and not as "nervous" as the more racy continental aeroplanes. With reduced load the 207 is, in fact, aerobatic and feels as if it would behave very well indeed under these conditions. Yet the aircraft was delightful to cruise and flew itself with the minimum of attention. Just before the Shackleton weekend, the German C of A was fully validated with just one alteration, a fuel shut-off valve to be fitted on the cabin side of the fire-wall. Externally the 207 is a very clean aeroplane, the wooden structure being carefully smoothed-off and the under carriage well spatted. The cabin comfortably holds four people, and front seats and rudder pedals are adjustable, though not quickly. Both upward-opening doors spring open when released and are fastened shut by normal latches and snap-over catches. A stout crash-pylon is reassuring. The climb into the front seats can be difficult, except that the outboard elbow rests can be folded down to provide a good footstep on the seats. Full blind-flying instruments, engine instruments and one Becker transistorized AR12M 12-channel VHF radio leave just enough room for one more small radio and VOR indicator. A padded plastic quilting covers the panel. All the push-button switches, levers and circuit-breakers form a single row along the bottom of the panel, with vernier pitch and throttle plungers in the middle and a keyed push-pull knob for selecting left or right fuel tank. Right tank is required for take-off and landing, because the hand- operated emergency pump draws from that tank. Pendant rudder pedals carry excellent toe-brakes, and these are used for steering. For take-off and landing, the tailwheel is locked from a catch between the seats. Tailplane incidence and flaps are controlled by two plastic winding wheels, also between the seats. Visibility is good. I could lean forward and see sideways in a steep turn, while being otherwise shaded by the central roof section when cruising. The intake pressure gauge is marked in atmospheres (1.0 is 29.92in and 0.8 is 24in) and the cooling gills are simply set before take-off in accordance with the average ambient temperature. They do not normally have to be reset during flight. There is a cylin der-head temperature gauge. With four people on board, we taxied out in the 30kt wind at Sywell and had no difficulty controlling the 207 on the ground The nose obscured forward visibility only slightly. Take-off was completely straightforward and we climbed straight up to 2,000ft to get out of the worst of the bumps. Once settled at 120kt I was immediately struck by the sweet handling of the aeroplane. The ailerons were very smooth and co-ordinated turns required virtually no rudder. After a kick of rudder, the nose centred immediately and longitudinal stability was almost as precise. The trimmer was excellent and the rather nose-down cruising attitude could be set with no difficulty. Very little effort was needed to apply the first 40° of flap, which is the normal maximum. After that, an orange light shows that the final, so-called emergency setting is being applied. The recom mended forced-landing technique is to descend with 60° of flap at 80kt, at a startlingly steep angle, and to set the aircraft down wherever necessary. All flap settings produced a normal trim- change. Clean, the 207 stalled with a moderate wing-drop to one side or the other at about 55kt. An unusually loud stall-warning horn blew at about 65kt; and a second much rougher stall followed if the recovery from the first was too hastily made. With 15° of flap, the stall was much more gentle, at about 50kt. The normal maximum 40° of flap produced a stall at 40kt which could be held straight with aileron or rudder, and from which recovery was immediate With 60° flap at 60kt (80kt seemed to require a very steep nose-down attitude), we went downhill at l,000ft/min, giving a very steep descent angle. Application of full power sent the nose up smoothly but the rate of climb was negligible. This is where 180 h.p. usually proves to be a trifle inadequate. Flap would have to be reduced to make a successful overshoot at full load. Control remained very pleasant throughout the series of stalls, forces never becoming excessive and aileron effectiveness remaining rather longer than usual. I cruised around for some minutes, making a few wing-overs just to enjoy the beautifully smooth handling. We really moved along at a most impressive rate and noticeably covered more countryside than I had done in a smaller aircraft I had been flying immediately before. I had already noticed the apparently rather nose-down cruising attitude, but I did not appreciate the considerable attitude- change which follows flap extension until I made the landing from a normal approach at 75kt with 40° flap. On coming to round out. 1 suddenly noticed the considerable rotation needed to get into the three-point attitude, although the tail did not sit very low on that long tailwheel leg. Nevertheless, there was ample precise elevator for the purpose and landing went as smoothly as all the rest of the flight had done. Apart from the excellent performance and exceptionally pleasant feel, my main impression of the Bolkow 207 is of a very well and intelligently finished aeroplane. The details all seem to be right, the workmanship is clean, the fittings are sound and everything fits into the overall picture. It is the sort of aeroplane for which the salesman need make no apologies and no excuses. I certainly liked it a whole lot better than its forerunner, the Klemm 107C. In terms of miles per gallon and m.p.h., the 207 offers remarkably good value.
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