
      
      The 
      elegant fuselage shows several clever refinements. The front section hosts 
      the compact Mid-West rotary engine, which is installed from the top 
      between the carbon fibre engine carriers. The upper cowling, with its 
      shark-like cooling gills, is held by two spring steel wires, which are 
      pushed in from the front side and locked by snapping them behind a safety 
      plate. Beneath the engine, the air intake and exhaust section is covered 
      with a removable cover. In between engine and cockpit is a ballistic 
      recovery system, mandatory for micro lights in Germany. In an emergency, 
      it fires upwards through a lid held on only by clear adhesive tape. The 
      cockpit itself forms a modern safety cell, the basic idea of which has 
      been borrowed from Formula 1 racing car designers. Into the outer 
      honeycomb structure of the fuselage, an Aramid fibre cell is fitted. The 
      carbon fibre seat-pan with its stiff backrest to protect the pilot's spine 
      can be removed to enable the control systems to be reached. Behind it, in 
      the rear fuselage tube, a baggage compartment can be fitted, its loading 
      capacity limited by the centre of gravity, depending on the pilot's weight 
      (he sits behind the C of G). The pilot is strapped to the safety cell by a 
      modern four-point-harness, and the cell is directly fixed to the BRS. This 
      is a very safe cockpit, professionally manufactured.
      The electrically retractable main undercarriage 
      is hinged at the fuselage and rotates backwards around a diagonal axis. 
      While the 'legs' remain outside at the wing root bottom, the wheels with 
      their hydraulic disc brakes disappear almost completely into wells which 
      are half in the wing and half in the fuselage. Doors screwed to the legs 
      cover the wheels when retracted. The small covered tail wheel is 
      double-sprung a spring acting telescopically in the fuselage takes the 
      vertical loads, and a rubber block just above the wheel allows it to swing 
      backwards when small obstacles on the ground are hit.
      The control system is simple and 
      well-thought-out. Elevator and ailerons are operated by pushrods, the 
      rudder by cables and the flaps via a torsional drive by an electric motor 
      in the fuselage. The spring elevator trim is also electrically actuated. 
      Like a glider, the Silence can be rigged and derigged for hangaring or 
      transport in only ten minutes. Rigging is simple, and, if the fuel tanks 
      are empty, may be carried out by only one person. Once the wings are slid 
      into their slots in the fuselage, one eccentric bolt for each wing 
      underneath the seat pan serves to pull the wings in by swinging the bolt's 
      lever behind the securing spring metal sheet hook. The torsional drive of 
      the flaps connects automatically during assembly, while the aileron 
      pushrods have to be connected to the lower end of the stick by bolts with 
      securing Fokker safety pins. The fuel hoses, the wires of the fuel 
      indicators of both wings and the pitot pressure hose from the right wing 
      are connected by reaching through the undercarriage openings below the 
      fuselage. Finally, the tail plane halves are slid onto the aluminium tube 
      spar ends at the fuselage and secured by a spring steel wire pushed in 
      from behind, the elevator connecting automatically via a hexagon head 
      torsional link. If the rudder has also been taken off, it is inserted from 
      above and secured by two Fokker pins. A look underneath the cowling to 
      check whether there is enough cooling liquid and oil in the reservoirs 
      (the Mid West Harrier uses about 2.5% of the fuel consumed as 'lost 
      greasing oil'), before refuelling the tanks, and the Silence is ready to 
      fly.
      The cockpit is easily entered from the front side 
      by stepping onto the tire and then the narrow fuselage section of the wing 
      root. After pushing forward the canopy locking lever at the outside 
      fuselage surface, the canopy can be swung open towards the right side. The 
      pilot then slides easily into the well-upholstered, 
      ergonomically-designed, but non-adjustable seat: there is enough space 
      here even for tall pilots. A head-rest had not yet been installed on the 
      one I saw, but this can easily be done. The rudder pedals can be adjusted 
      separately by turning two knobs in the instrument panel: the designers are 
      considering connecting these two knobs together to avoid asymmetric 
      settings. The cockpit's large instrument panel is well equipped. The BRS 
      handle at the front frame is within easy reach and can be secured with a 
      lock. At the left cockpit wall, there is one small fuel cock. In spite of 
      the fact that there are two tanks, one fuel cock is enough because the 
      tanks are inter-connected. 
      
      The engine 
      takes the fuel from the left tank, which has no ventilation and is 
      refilled from the ventilated right tank. This system is very simple, but 
      comes with the disadvantage of asymmetric wing loading during flight. 
      However, as the tanks are close to the fuselage, this is not expected to 
      greatly affect the flying characteristics. Nevertheless, the manufacturer 
      plans to install separate fuel cocks in later aircraft to preclude the 
      possibility of asymmetric wing loading. The throttle is placed in the spot 
      where you would find the pilot's left hand in a relaxed position. The two 
      buttons for trim operation and also the transmitter button are placed on 
      top of a fighter-like control stick. The trim setting is indicated by an 
      electronic instrument. A knob in the instrument panel serves to set the 
      flaps to 0, 10, 20 or 30°, and a covered switch besides it operates the 
      undercarriage. In case of a failure of the electrical system, there is a 
      red emergency extension handle between the pilot's legs. If this handle is 
      pulled, the undercarriage is disconnected from its spindle drive and then 
      pulled out, assisted by gravity, until it is in the 'down and locked' 
      position. The status of the undercarriage (up, in transit and down) is 
      indicated by LEDs, other LEDs warn if the engine is operated outside its 
      normal parameters, although there are also conventional instruments 
      fitted.
      
      
      
      When I test-flew the 
      Silence V2 at Bielefeld-Windelsbleiche airfield on September 5, 2002, it 
      was not yet in final serial condition in fact, it had only made its maiden 
      flight the day before. The wheel covers for the undercarriage legs were 
      not yet fixed in place and the propeller was still a shortened, fixed 
      two-blade Helix unit. The planned three-blade electrically adjustable 
      Silence propeller, already used on the first prototype where it rotates 
      right-hand, was not yet available in the left-hand rotating version needed 
      for the Mid-West. Finally, the engine power was not yet fully available, 
      and resonance problems still required some adjustment to the air supply 
      system.
      On closing the canopy, it can be locked by 
      pushing backwards the small knob on the left cockpit wall. The main switch 
      and starter function are united in an ignition key lock similar to that on 
      a car. After switching the key to 'ON', the two ignition switches and the 
      two fuel pump switches beside the key are switched on. With the Mid-West 
      engine nothing runs without fuel pressure, so the second pump is a 
      mandatory safety feature for take-off and landing. With the throttle set 
      to a little above idle, the engine starts immediately on turning the key 
      to the 'start' position. It runs a bit rough below 4,000rpm and only 
      becomes smooth above 4,000rpm typical behaviour of one-disc rotary engines. 
      To protect the ears from the relatively high frequency engine noise, a 
      good headset is recommended. The time needed to warm up is short, and 
      after checking the ignition and fuel pumps, the Silence is ready for 
      take-off. During taxiing I found the separate toe brakes effective and 
      easy-to-operate, and the tail wheel, spring-connected to the rudder, easy 
      to steer. By using differential braking, quite tight turns are possible. 
      My eyes were just at the height of the narrow front cowling tip, so I did 
      not need to taxi in a zigzag to get a decent view.
      
      
      
      This Silence weighs 
      exactly 441lb empty. With me in the cockpit and 11 Imp gal of fuel 
      (standard 92 oct car fuel), it weighs 683lb: even with full tanks I would 
      still be below the maximum permitted 750lb. The centre of gravity is in 
      the forward range. For take-off, I turn the flaps knob to 10° and set the 
      trim to neutral. After pushing the throttle forwards until I reach 1cm 
      behind the front stop (because of the resonance problem mentioned earlier, 
      the engine starts coughing with more throttle), I accelerate quickly with 
      the stick held slightly forward. 
      
      As soon as the tail wheel lifts off, I 
      need a small amount of left rudder to compensate for the propeller torque. 
      At 43kts it lifts off, and I let it accelerate to 60kts before starting to 
      climb. At a safe height I retract the undercarriage, set the flaps to 0° 
      and switch the second fuel pump off. In this clean configuration, I find 
      the best climb rate at 65kts, and although the engine performance is not 
      fully available it climbs at about 790ft/min. With the engine problem 
      solved, I expect the aircraft to climb in excess of 1,000ft/min. The 
      heavier prototype with the 65hp engine which I flew in the spring climbed 
      at nearly 1,180ft/min. Trimmed to the best climb speed of 65kts, only a 
      small amount of left rudder is needed to keep it flying straight. On 
      reaching 2,500ft, the engine's three minutes of permitted full power 
      operation have passed and the cooling liquid temperature comes close to 
      its maximum. I reduce the power to the maximum continuous setting of 
      7,100rpm and continue climbing at 70kts, with the result that the 
      temperatures remain in the green arc.
      
      
      During 
      cruise flight, this rpm limit is already reached at 86kt with the current 
      Helix propeller. The prototype, equipped with the Silence-developed 
      three-blade variable pitch propeller, reaches more than 108kts with no 
      problems. In this aircraft, and probably also the Mid West-powered ones 
      equipped with the new propeller, the 17.6 Imp gal of fuel makes possible 
      620-mile flights at a cruise speed of around 100kts.
      I am particularly impressed with the handling of 
      this little aircraft. The control forces remain very low, though positive, 
      for just about the whole speed range. The Vne of the 'Experimental' 
      version is calculated as 162kts, though it is only 140kts for the micro 
      light version due to the limited operating speed of the BRS. The 
      sensitivity of the Silence gives the impression of flying a 
      fully-aerobatic aircraft, and trimmed to cruise speed it flies beautifully 
      stable in the 'hands off' position. However, if the right fuel tank is 
      empty and the left one full, a small amount of aileron deflection is 
      needed to keep the wings level. 
      These excellent general handling 
      characteristics are further supported by the excellent view through the 
      big canopy and the good fresh air supply through the nozzles in the front 
      cockpit frame. Cabin heating is also installed, though in the current warm 
      weather I feel disinclined to test its efficiency. The only thing I miss 
      is a small 'direct-vision' panel in the canopy I once experienced outside 
      cabin icing when descending with a cold glider through an inversion layer 
      into warm, humid air, and opening this window then saved me from being 
      'blind' and lost... How does such an elliptic, fully-symmetric wing behave 
      when it is stalled? 
      I was quite astonished at the gentleness of the 
      stall. With the engine running at idle and the flaps at 0°, the Silence's 
      controls start feeling soft at 43kts: at 40kts the stall starts buffeting 
      and speed increases to 43kts again in the staggering stall, where it can 
      be held by using the rudder. With the elevator further back, staggering 
      increases and I start feeling as if I am sitting on a wild horse, though I 
      can still prevent it from departing into spin with the rudder. I think 
      this effect is caused by the turbulence separating behind the wing root 
      (which was probably stronger than usual due to the uncovered retracted 
      wheels underneath the wing) hitting the tail. With its forward C of G 
      position, the Silence starts dropping the nose, but immediately the 
      airflow comes back to the tail plane, the game starts again. 
      Setting the flaps results in the same 
      behaviour, 
      with the minimum indicated speed decreasing by about 2kts per 10° of flaps 
      set. With full throttle, the indicated speeds are again 1kt lower. The ASI 
      of this aircraft had not yet been calibrated and seems to over-indicate 
      slightly with the prototype, a calibrated airspeed of 35kts at 750lb AUW 
      has been demonstrated during the certification. When I flew this prototype 
      with an aft C of G and the wheel covers fitted, the staggering was less 
      pronounced. It did try to drop a wing, although the incipient spin could 
      be stopped immediately by relaxing the stick and applying opposite rudder. 
      The Silence shows excellent control harmony. With the engine running at 
      idle and trimmed to 70kts, it raises the nose and starts climbing at 65kts 
      once the throttle is opened fully. Setting the flaps (below 65kts) to 
      different positions does not really influence the trimmed speed. Its roll 
      rate is impressive: when full rudder and aileron are applied, even at the 
      slow speed of 59kts it rolls from 45° to 45° bank within 1.5 seconds 
      without side slipping. This roll rate is practically aerobatic, and care 
      has to be taken not to stall the lower wing when applying full aileron and 
      not enough rudder against the rolling direction. But even in such a 
      situation the Silence is straightforward a kick into the rudder against 
      the rotation direction stops the initial snap roll immediately.
      
      
      
      The 
      manoeuvring speed, up to which full control deflections are permitted, is 
      97kts, and the maximum allowed speed to fly through stronger gusts is 119 
      kts, clearly above cruising speed. Compared to other fast micro lights, in 
      which you should cut your flying speed considerably when flying on a day 
      with strong thermals, this gives a good margin of safety. Of course, these 
      flying characteristics may tempt some to try a few aerobatics. However, 
      the rules of the micro light category set clear limits aerobatic are 
      generally prohibited in these aircraft. Anyone with ambitions in the 
      direction of aerobatics could always buy the strengthened kit Silence 
      Aircraft offers. If the builder completes it at home and certifies it as 
      an aerobatic aircraft in the 'Experimental' category, there are no limits 
      to gambolling around the sky (and probably outclassing the Tipsy Nippers 
      and RF-4s you can hardly ever find in the second-hand market...).
      The electric flap drive acts rapidly. Within 
      three seconds the flaps reach their maximum of 30°: the undercarriage 
      needs 7.5 seconds for retraction and 9 seconds for extension. The maximum 
      speed in landing configuration with the flaps set to 30° is limited to 
      65kts. Under calm weather conditions, I find an approach speed of 56kts 
      comfortable and perfectly safe. Before landing, I switch the second fuel 
      pump on again. The flaps are effective, and with the engine running at 
      idle it is easy to control the glide path. Side slipping is very easy and 
      effective, permitting very steep approaches and further improving the 
      pilot's (already good) view of the runway it also feels as if it's the 
      right way to land an aircraft resembling a Spitfire!
      Provided you stopped side slipping after holding 
      the Silence off until the nose was at the correct attitude, and that you 
      centralized the rudder before the wheels touched the ground in a proper 
      three-point attitude, the Silence will land gently. If you do not follow 
      the advice given above, it will 'dance' 
      a little on the runway, due to the un-damped, but 
      sufficiently sprung undercarriage. Even a strong or gusty crosswind causes 
      no problems, though some tail dragger experience is useful to produce a 
      good landing on a concrete runway (and to keep the aircraft there 
      afterwards!) For new Silence pilots, I would recommend making your first 
      few landings on a more forgiving grass strip. The rudder has to be used 
      carefully during the ground run the separate toe-operated hydraulic disc 
      brakes are easy to use and quite powerful. As the main undercarriage is 
      well in front of the C of G, the risk of nosing over is relatively low.
      As a single seater of the upper micro light 
      class, the Silence is not for everyone, and it does require the pilot to 
      have a certain level of tail dragger experience. Flying it is enormous fun 
      as it offers a high level of performance combined with excellent safety 
      features. The Mid West 'Harrier' single disc rotary engine suits its slim 
      appearance, though it consumes a relatively large amount of fuel and is 
      not the smoothest of engines, particularly at low rpm. With this in mind, 
      Silence Aircraft is considering equipping the aircraft with the 75hp 
      Walther Minor IIIB air-cooled in-line four cylinder engine. Used as a 
      micro light, the Silence's operational range is fairly limited by the 
      definition of this aircraft category however strengthened versions 
      certified in the 'Experimental' category, built at home from a 
      pre-fabricated kit, may be used for aerobatics and show the full range of 
      this design's abilities. The great interest that these first 'little 
      Spitfires' attracted whenever they appeared demonstrates clearly that a 
      large market is out there waiting for the Silence!
      On reaching 2,500ft, the engine's three minutes 
      of permitted full power operation up to 7,750rpm have passed, and the 
      cooling liquid temperature comes close to its maximum. Reducing the power 
      setting to the permanently permitted 7,100rpm and continuing climbing at 
      70kts results in the temperatures staying in the green arc. Right Straight 
      from the box the kit is well-produced and has the benefit of considerable 
      prefabrication.
            
             
              
               
               
               specifications 
 
              
                
                powerplant 
                propeller 
                length 
                height 
                wing span 
                wing area 
                seats 
                empty weight 
                
                useful load 
                gross weight 
                fuel capacity 
                range | 
                
                        80 HP
                        JABIRU 2200 
                
                        2.blade 
                        
                        
                        
                        GT propeller 
                
                x 
                
                x 
                
                x 
                
                x 
                1 
                
                        
                        500
                        
                        
                        
                        
                        
                        lb. 
                x 
                
                        880 
                        
                        lb 
                
                        
                        21 US
                        
                        
                        
                        
                        
                        
                        
                        gal 
                800 nm | 
               
             
            
            performance 
            
             
            
              
                
                takeoff distance, 
                ground roll 
                rate of climb 
                max speed 
                cruise speed 
                landing distance, ground roll 
                
                
                service ceiling | 
                
                x 
                
                        
                        1500 ft/min 
                x 
                
                        127 
                kts 
                x 
                x | 
               
             
            
            limiting and recommended speeds
             
            
              
                
                design manoeuvring speed (Va) 
                never exceed speed (Vne) 
                stall, power off (Vsl) 
                landing approach speed  | 
                
                        
                        135 
                kts 
                
                        196 
                kts 
                
                        41 
                kts 
                x | 
               
             
            All specifications are based on manufacturer's 
            calculations 
   |