Taken from the book

FIGHTER TEST PILOT

From Hurricane to Tornado

By ROLAND BEAMONT

Fw190 WAR replica

Two dates 13^th September 1943 and 30^th march 1980, had a certain similarity for the author as both involved flights in the Fw 190. The fist was the original focke wulf captured intact in 1943 when it landed at Fariwood Common in sth wales, and the second was a surprisingly close replica to ½ scale build in 1979 by mike searle of Aero services Ltd at Elstree. There the similarity might have ended for the wood and glass fibre construction replica weighed only 1,010lb with its 100hp Continental 0 200 a engine, while the original weighed 8,600lb and had around 1,700hp from its fan cooled bmw 801d radial 14cyld, twin row engine" but there turned out to be rather interesting similarities.

The replica, G-WULF, designed by War Aircraft Replicas in America, had a span of 26 ft and length 16ft, so it was very small aeroplane indeed and gave a fist impression on close acquaintance that it had escaped from a model aircraft rally. In general appearance it was an almost true replica of the real thing with wing, rear fuselage and tail, undercarriage and underfuselage bomb/longrange tank rail all looking accurate. The cockpit area was realistic also with a true looking windscreen and canopy profile" but the rear half of the canopy let the accuracy down as the transparency was cut off just behind the dummy armour plate where on the original , and outstanding feature was the long clear view rear canopy extending half way to the tail.

Forward of the windscreen the engine cowling was a clever simulation of the original with the exhaust system terminating realistically in four ejector stubs as side, three of which were dummies. Only a look thrugh the nose intake revealed not a lusty twin row radial engine but the 0-200A which was well cooled without the benefit of the originals fan cooling.

The propeller was of wood, three bladed, skinned in grp (glass reinforced Plastic) and finished in back, and with a well proportioned back spinner painted with the while spiral of the period it all looked very realistic. Only a long, critical look revealed two basic dissimilarities: the wing had noticeably less dihedral and the cockpit/windscreen was slightly further aft than on the original. Nevertheless, without another aircraft to give it scale the replica did look very like its exciting original and in flight the sight of it seemed likely to give cold shivers to ww2 veterans!

Walk-round checks showed a high standard of skinning and detail finish, and commendably low static friction on all controls and absence of noticeable backlash. The tail wheel was steered through conventional springs and the retracting undercarriage was noted to have a comfortingly simple linkage and geometry. It was thought likely to be prone to the accumulation of mud/ grit from the wheels (shod with go-cart tyres!) and that this would need to be the subject of regular maintenance checks.

Climbing into the cockpit of this aircraft was, for this low aspect ratio pilot, akin to pulling on rather tight trousers, and in fact getting out of it subsequently was the only difficult part of the whole operation! However, once seated in the comfortable semi-reclining seat with the feet resting on the rudder pedals virtually under the rear of the engine, it proved to be a comfortable cockpit with all controls and switches within easy reach.

Of particular interest wast he stock grip which, while providing a reasonable representation of the shaped grip of the original 190, was in practice an American p-86 style stick and very comfortable in use.

The report (abbreviated ) on this flight recorded the following:

G-WULF Popular Flying association assessment – Leicester East.

"The aircraft was flown (for PFA permit assessment) in moderate/improving weather conditions, and in the presence of light training and club traffic which limited some aspects of the tests.

The cockpit, though appearing very small, proved to be comfortable when settled and strapped in. the zlin five-point harness installed was cumbersome to fit but comfortable with good restraint when adjusted.

All controls and switches could be reached and operated with straps tight, and full control deflections could be achieved although full aileron with "up" elevator was resisted by the thighs.

Instrument panel layout was easily identified and well captioned, but vision of ASI and Rev counter was restricted at the top third by the coaming and the E2 compass. Grouping of engine references was haphazard with cylinder head temperature (CHT) top left, oil pressure (OP) and temperature (OT) bottom left, Amps bottom centre and rpm top right. A more suitable arrangement would be conventional grouping of all these below/ right of the rpm gauge.

The tail down, nose high attitude was marked when strapped in, and with the canopy shut head movement was restricted.

Engine start immediate, ground idle 600rpm: fuel 11gall CHT 150, OP 45, OT 55, amps +1.

The flying controls were free of noticeable static friction and backlash, and the throttle and fuel cock were well positioned and easy to operate the rudder pedals were found to have a noticeable amount of fore aft spring loaded free play when both pedals were equally depressed (not brake pedal rotation). This proved to be undesirable in taxying and take-off/landing run control, as it reduced direct feel of tail wheel steering.

With no parking brake, starting and ground running required restraint by brake pedal operation which proved adequate.

View ahead was largely obscured by the hight nose, and safe taxying required swinging the nose (as did the original Fw 190) tailwheel steering was adequate once the fore/aft rudder pedal movement had been allowed for.

With cold outside air temperature (OAT) (+6oC) the small windscreen and canopy misted quickly with canopy shut, and the absence of a fresh air vent was noted.

When checking the movements needed for activation of the manual undercarriage emergency DOWN selection it was felt that this was likely to be a difficult operation.

At full power, acceleration was brisk but there was no tendency for self-lift of the tail which needed light but positive forward stick to achieve take-off attitude. Prior to this, total lack of forward vision resulted in some slight veering about the runway centre-line.

Unstuck at approx 55kt and initial climb held at a comfortably steep angle at 70kt. Under-carriage retraction complete in 9.5 sec. Red and Green indicator lights satisfactory. No noticeable trim change, noise or buffet associated with undercarriage down, or when retracting.

Three axis control responses, 100ft/100kt:

Pitch- light, positive and dead-beat;

Aileron - light, crisp and dead-beat;

Rudder - very light and powerful, but well damped.

Aileron/elevator harmony excellent, but rudder lighter and out of harmony.

However, it was soon apparent that with excellent weather-cock stability and crisp response and damping in all axes, rudder co-ordination was seldom necessary and its lightness was not noticeable except when deliberately assessing sideslips etc.

Rolling power was hight with 360 deg barrel rolls executed smoothly at 100 deg/ sec +, and about 2.5lb to full deflection.

Stick force per g was light at 1.5lg/ g estimated, but with no noticeable static friction or backlash and with dead-beat damping these low values were very satisfactory for fighter- type manoeuvrability. Crisp "hesitation" rolls were practicable.

At all speeds above 100kt, rpm needed controlling against overspeeding and this was easy to manage with smooth, responsive throttle, but had to be remembered.

IAS increased to 165kt (Vne 175) in shallow dive with only moderate increase in noise level, and all control responses as before thought heavying slightly. Noticeable in mild turbulence that tracking accuracy remained dead-beat and excellent.

2000ft; 9.5 gal, slowdown to "clean" stall.

As IAS reduced below 60kt for the first time in the flight a nose-up trim adjustment would have been needed for stick-free trim, but was not made.

Stall 42kt. Slight buffet from 43kt. Left wing smooth roll away, checked instantly by small forward stick.

Repeat gear down. Effects of gear lowering at 70kt hardly noticeable. Stall buffet as before 43kt: left wing drop at 42kt.

Throttle response at stall good.

From 70-160kt the aircraft remained in lateral and directional trim controls-free and needed hardly any pitch adjustment.

Longitudinal static stability was positive and well damped throughout the speed range 42-160kt.

Sideslips - 1500ft 1.3Vs power on 9 gal.

Left and right rudder. Strong weathercock stability and light aileron force to hold. (Positive lateral stability, sideslipped wing rises.)

During all low engine-power points the undercarriage warning horn operated correctly with acceptable noise level in the headset.

Right-hand circuit and approach to runway 28.

At 70kt and below, the very nose-high attitude was restrictive and confirmed that straight-in approaches would be unsuitable for this aircraft below about 80kt (which would result in the complication of losing excess speed on this flapless aircraft during final approach).

On overshoot from 100ft/70kt about 2/3 throttle gave good response and a steep climb while retracting undercarriage from 80kt – time 12 sec.

Left-hand circuit and continuous curve approach at 70kt maintained vision of the threshold until rollingout and flaring at about 10ft when all forward vision was lost, direction having to be maintained by alternate side viewing of the runway edges.

Control in the flare was precise on all axes and it was easy to hold level as speed bled off slowly in a long float until gentle touchdown, but in the initial roll-out some veering occurred due to the restricted vision references coupled with rudder pedal "sponginess".

After a second take-off;

From 2,000 ft/ 90kt. Left turn dynamic stall, 7 gal.

Power increased to achieve 3g/70kt in level turn. Left wing drop with short buffet. Stopped immediately with slight forward stick.

Repeat in right turn with same result. If stick held at wing-drop the incipient spin would develop but was controllable with forward stick.

This was not investigated beyond ½ turn.

Wing-overs from 120-60kt and loops from 160kt were smooth and elegant, but if pulled too tight below 75kt would depart left-wing with recovery as above.

Engine smooth and responsive with stable indications and good cooling throughout.

This 1.10 hr flight, and radio performance on 122.25 with RAF inner helmet and 1945-standard mask/headset, clear and satisfactory.

Final left-hand continuous curve approach at 70kt satisfactory.

Roll-out and flare over threshold at 67kt and long "blind" float before gentle touchdown on final landing. Braking action smooth, but difficult to prevent veering until slow speed for the reasons above.

Conclusions

G-WULF has been described by Mr F.I.V Walker as well built to professional standards. Flight experience supports this and the aircraft has exceptional control qualities for any aircraft in this category. It is a pleasure to fly and well within the capabilities of suitably experienced tail wheel pilots, with the one exception that forward view is not merely restricted but is non-existent for straight taxying and in straight-in approaches. This aspect will need to be covered in Pilots’ notes and by strict supervision of conversion training. It could use a wing-flap system.

The aircraft was not found to have any other vices, although its tendency to roll out of a looping pane manoeuvres into incipient spin if uncorrected needs taking account of in planning flight demonstrations.

Full performance measurements were not made on this flight, but there is a comfortable excess of power for missed approaches without swing or trim changes. One-minute stabilisations at 1000ft showed 135kt at 2,500 rpm, and 150kt at 2750.

Its mini-fighter style qualities are enjoyable and confidence-making to a point which might cause inexperienced pilots to exceed their own capabilities, and this must be guarded against.

In all a very attractive hight-performance single seat aeroplane with hight quality and predictable control characteristics, generally symmetrical trimming and a smooth engine installation helped undoubtedly by the three-blade propeller; but an aircraft which needed supervision in conversion training due to severely limited forward vision in its necessarily flapless approaches which tended to result in excessive threshold speeds, long floats and hold-offs and therefore relatively lengthy landings runs, particularly if associated with wet grass. This was a fun aeroplane of hight quality, and a credit both to its designer and to owner and builder Mike Searle.