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CHEETAH
effective by 20kt. In view of the crosswind we delayed
lifting the nosewheel off until after the recommended
speed of 50kt, and some lOkt later a gentle ease back
lifted us cleanly off the ground. For a short take-off the
Cheetah can be pulled off at 50kt, and it is a rebuff to
the old argument about the use of flap for take-off that
the manual recommends no flap for either a soft-field or
short-field take-off. Best angle of climb speed is 68kt and
for best rate of climb the manual recommends 79kt. We
averaged 80kt through some gusty, unstable air, recording 650ft/min up to 4,000ft. This figure, produced two-up
at the maximum utility weight of 1,8501b, was disappointing, being similar to Grumman's figure for a grosswweight
climb at sea level. Suspicions that the engine sounded a
trifle lumpy and down on power were confirmed when we
leaned the mixture a couple of minutes later after reduce
ing power in the cruise. This produced another 125 r.p.m.,
showing that it was evidently running over-rich.
Visibility in the climb we thought was well above
average. The pilot of average height can almost see the
horizon over the front of the cowling and needs only a
tiny weave of the nose to clear the blind spot ahead. The
centreline bulge behind the spinner makes a good datum
for precision visual flying, and must be a small but useful
asset to both instructor and student using the Cheetah
as a trainer.
At 4,000ft we levelled at 75 per cent power, and when
the speed had settled we recorded 126kt TAS. Full
throttle, we found, would not quite meet Grumman's
brochure figure of 157 m.p.h. for 150 h.p., but nevertheless
produced the rare figure of one m.p.h. for every horsepower at the utility weight. Noise level was quite low for
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this class of aeroplane and without headsets conversation
in both front and rear needed little effort.
We like Grumman controls, and the Cheetah came well
up to expectations. The modern metal four-seater still
tends towards rather gutless handling, driving the pilot
who wants to fly for flying's sake towards a purpose-built
sport aeroplane such as a homebuilt, biplane or vintage
aircraft. Such a pilot ought to find a lot of satisfaction in
the Cheetah, which gives him the almost old-fashioned
virtues of crisp control response, light stick forces, and
surely the best pair of ailerons on any comparable production American four-seater. Putting the Tiger's tailplane
and elevator on what is virtually still a Traveler airframe
has improved the stability in pitch, and a lOkt speed displacement damped out in some two cycles. At all times
the elevator stick force was comfortable and well matched
to the delightful ailerons.
Stalling proved to be as docile as we could wish for. A
clean, power-off stall triggered the warning at 60kt, leading after very little buffet to a gentle but perceptible
break at 53kt with the wings level. With full flap the
warning came at 55kt and the break at 48kt after a firm
pull to the back stop. Stalling the Cheetah trimmed in an
approach configuration with full flap and 1,500 r.p.m. led
to equally docile results, and both rudder and aileron
control were still available at less than 55kt. Power off and
again with full flap, the Cheetah could be held nose-up
in a wallowing descent at 50-55kt, with the VSI reading
over l,000ft/min but still with aileron and rudder response.
Stalling in a turn needed a firm pull and after a light
buffet the Cheetah consistently rolled level out of the turn.
Having descended towards Cranfield we found that lOOkt
was a comfortable downwind speed. This put us within
the flap limit speed of 103kt. Grumman flaps are relav
tively small in size, trim change and effect, and full flap
is really the norm for most landings.
Being a touch slippery and relatively under-flapped, the
Cheetah calls for accurate approaches and speed control.
The good handling at lower speeds showed up when we
were asked to do an orbit late on finals to fit in with busy
runway traffic. Normal approach speed is 65kt, and this
proved to be ample, giving positive control in all axes
and leaving some float after the flare. The Cheetah
responded well to either the crabbing or wing-down
cross-wind technique, or—as is often the case at touchdown
on a gusty day in a light aeroplane—a combination of
both. On a normal into^wind landing the Cheetah flight
manual makes no bones about its advice to "hold the noser
wheel off as long as possible on roll-out," and there was
adequate elevator response left to do this.
Grumman's Cheetah is a very attractive, vivacious cat
with habits as clean as its four-legged counterparts'. Its
performance is still something to be reckoned with
amongst 150 h.p. four-seaters, and it deserves to find a
home with the pilot who wants a touring aeroplane with
a difference.
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