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  • Flight Test

    Here is a flight test I copied from somewhere.
    Worth a read to compare.

    Neil

  • #2
    Flight Test

    [6]

    Technical Data
    [/6][1]
    Mainair Gemini Flash 2 Alpha 462

    Mainair Sports LId, Unit 2,

    Alma Industrial Estate,

    Regent Street, Rochdale

    0L12 0HQ; tel 0706 55134;

    fax 0706 31561. Directors:

    Paul Frain, Eileen Hudson.

    SUMMARY

    Tandem two seat flexwing aircraft with weight-shift control. Rogallo wing with fin and keel pocket. Pilot suspended below wing in trike unit, using bar to control pitch and roll/yaw by altering relative positions of trike unit and wing. Wing braced from above by kingpost and cables, from below by cables; floating cross-tube construction with 76% double-surface enclosing crossube; 19 battens on top surface, 8 battens on undersurface, plus 4 Intermediate battens. Undercarriage has three wheels In tricycle fomation; gas spring damper suspension on nosewheel, coil spring and gas damper suspension on main wheels. Push-right go-left nosewheel steering independent from aerodynamic controls. Drum brake on nosewheel. Aluminium-alloy tube tribe unit, with standard tibregless pod. Engine mounted below wing, driving pusher propeller.

    EXTERNAL DIMENSIONS & AREAS

    Length overall 3.46 m, 11.4 ft. Height overall 3.83 m, 12.6 ft. Wing span 10.60 m, 34.8 ft. Chord at root l.48m, 4.88ft. Chord at tip NC. Dihedral 2 1/2°. Nose angle 130°. Wing area 15.6 m², 168 ft². keel pocket / fin area 0.38 m², 4.1 ft². Aspect ratio 7.1/1. Wheel track 1.52 m, 5.0 ft. Wheelbase 2.03 m, 6.7 ft. Main wheels diameter overall 4lcm,16 in. Nosewheel diameter overall 41 cm, 16 in.

    POWER PLANT

    Rotax 462 liquid-cooled twin-cylinder vertical two-stroke. Max power 52 hp at 6500 rpm. Propeller diameter and pitch 2.44 x 1.73 m, 62 x 44 inch, three-blade. Integral gearbox reduction, ratio 2.58/1. Max static thrust 106 kg, 233 lb. Power per unit area 3.34 hp/m², 0.31 hp/It². Fuel capacity 46 litre, 10.1 Imp gal, 12.2 US gal.

    WEIGHTS & LOADINGS

    Empty weight 148 kg, 326 lb. Max take-off weight 370 kg, 816 lb. Payload 222 kg, 490 lb. Max wing loading

    23.8 kg/m², 4.86 lb/ft². Max power loading 7.1 kg/hp, 15.7 lb/hp. Load factors NC recommended, +6g, -4g ultimate.

    PERFORMANCE*

    Max level speed 70 mph. Never exceed speed 89 mph. Economic cruising speed 52 mph. Stall speed 28 mph. Max climb rate at sea level 850 ft/mm. Mm sink rate 380 ft/him at 35 mph. Best glide ratio with power off 6/1 at 50 mph. Take-off distance to clear 15 rn obstacle 147 rn on grass. Landing distance to clear 15 m obstacle 80 m on grass. Service ceiling 17,000 ft. Range at average cruising speed 220 miles. Noise level 78.7 dB(A) 111.

    • Under the following lest conditions
    —Airfield altitude 0 ft. Ground temperature 15’C. Ground pressure 1013 mB. Ground windspeed 0 mph. Test payload 370 kg, 816 lb.

    PRICE

    £8700 including VAT.

    Data above supplied by manufacturer; data in text is tester’s experience.
    [/1][7]
    eXCursion
    [/7][1]

    [/1][4]
    Introduction
    [/4][1]
    I have been wanting to test the Mainair Alpha for some time, but the Alpha we have at Shenstone seems to be on the ground for only short periods [/1][1]— [/1][1]and when it’s in the air it seems to be on a permanent cross-country.

    The machine tested, G-MVRM, belongs to Mark Heynes of Midland Microlight Flying Club and at just over a year old was nicely run in, both as regards engine and wing fabric.
    [/1][4]
    The Wing
    [/4][1]
    The airframe is a conventional CFX (concealed floating crosstube) design using a rear vertical fin for yaw stability. The Alpha also has 100% double surface wing tips, a design feature first seen on the Flash 2. Interestingly enough, Solar Wings uses this type of tip on its hang gliders but not on its microlights. The idea of 100% tip coverage is to clean up the airflow and reduce the performance-sapping drag associated with all airfoils.

    The quality of manufacture is good, with Mainair’s normal careful attention to detail showing through in a well built product. Being a tight wing, it requires a host of battens to support the airfoil shape in flight— a total of 31[/1][1] [/1][1]no less. Not all of these are on the surfaces themselves: a Mainair innovation is the use of intermediate battens, and, just to prove that cross-fertilisation works both ways, this idea has been taken up by some hang glider manufacturers!

    The wing is erected in the normal manner, both the kingpost and fin support being permanently fitted. The crossboom tensioning cord is easy to operate and it is withdrawn into the wing out of view after use. Three leech lines are provided to give the wing reflex at low angles of attack. These are adjustable, but the job is best left to someone with experience! Tensioning is completed by inserting the swan nosecatch and operating an overcentre catch on the upper rear rigging wire. There are no tip struts on the Alpha: minimum washout is determined by an adjustable stud located on the leading edge, which I presume also provides a degree of adjustment for tuning out turns in the wing.

    The overall impression gained is one of strength coupled with quality of build and good attention to detail.[/1][2]
    [/2][4]
    The Trike Unit
    [/4][1]
    First impressions of the trike unit are exactly the same as for the wing: high build quality and high specification. Certainly the Alpha is not lacking in showroom appeal. For instance, there is ample use of glass fibre, both in the voluminous pod and the very attractive engine cowling. The pod, which has a fully enclosed front wheel (no draughts up the trousers!), has ample space for stowing XC kit with no chance of anything falling out Similarly, instrumentation space is more than adequate, so much so that it would cost a fortune to fill it up!

    The siting and operation of the foot controls is the best I have seen to date, particularly the foot throttle very good. The left foot control operates a front drum brake on an alloy wheel. The wheels are a one-piece design, which is good news for tyre life, as the split-rim wheels previously used on other manufacturers’ products are prone - [/1][1][/1][1]in my view unacceptably prone - [/1][1][/1][1]to puncturing the tube.

    Bumps are damped out by the Aerotrak suspension system. With its airfoil section compression struts, this certainly looks good, but l was less impressed with it in taxiing: I feel that gas dampers are better suited to car tailgates than aircraft suspension systems. Moreover, I am still unconvinced that a floating triangular structure is as strong as a rigid one.

    Many people regard the Alpha as the ultimate cross-country machine and it certainly can carry a lot of fuel. The main tank is located under the engine and is manufactured of clear polypropylene, allowing the pilot to see the fuel inside. However, this is difficult with a rear passenger, so many Alpha owners have located mirrors at convenient positions to see how much fuel is left. A secondary tank is available as an option and is located under the pilot’s seat, where it is accessed through an in-flight change valve. Both tanks are detachable for Round Bntain Rallies and the like - and you can go a long way on 50 litres.

    The engine on G-MVRM was a 462 liquid-cooled Rotax with disc valve and low-noise carburettor. The engine installation is good with an adequate radiator. An idea which I believe is unique to Mainair is to warm the fuel before it enters the carburettor: this should help reduce the possibility of carb icing, though it does nothing for the thermal efficiency of the engine. Apparently the three-blade propeller on the test machine proved fiddly to setup, but has given little trouble since.
    [/1][2]
    The trike unit attaches to the wing with the normal single hang bolt and there’s also a back up cable, though this must surely be mainly a psychological aid - has there ever been a hang bolt failure in the history of microlighting? (Yes, one, not on a Flash - Ed).
    [/2][1]
    Fully rigged and ready to fly, the Alpha certainly looks the part: an elegant, purposeful flexwing designed with the cross-country pilot in mind. So how does it fly?
    [/1][4]
    In the Air
    [/4][1]
    As we carried
    out ourpre-flight the least attractive feature of the Alpha came to my attention. With the port wing touching the ground and the A-frame hard against the front compression strut, the rear flying wires come perilously close to the propeller tip, so much so that if a minimal downwards bending movement is applied on the keel (replicating negative G) the propeller contacts the rear flying wires.

    In the normal flight envelope, with the keel positively

    The Flash 2 Alpha is easily distinguishable from the Flash 2 (seen in the background) by the chisel-nosed pod. This example has a 503 air-cooled unit, unlike the test machine.

    loaded, the clearance meets the Section S requirements, but this might not be the case at high angles of attack and bank or in a negative G situation. Of course, no intelligent pilot intentionally flies in such attitudes, but... For the same reason, don’t start up the engine with the wing parked into wind and the trike on soft sand, it could spoil your day - indeed, there’s a warning note in the handbook to this effect

    Checks over, I climbed aboard and immediately found the seating arrangements very comfortable, with plenty of room in that voluminous pod plus those excellent foot controls. The choke lever is tucked away under the front seat, so there’s no chance of mistaking it for the hand throttle, while the ignition switch is on the side where it is protected from misuse by the passenger or inadvertent operation by the pilot. Full choke and no accelerator, the engine fires up in no time at all and is impressively smooth. I attribute this to the three-blade prop which felt just right, purring away behind.

    Turning whilst taxiing takes a little getting used to as the unit wallows on the suspension and it’s at this point that one wonders whether the wheels are going up and down or the monopole swaying from left to right. But one soon gets used to it. Since the early Alphas, the springs have been beefed up and it’s fair to say that the ground handling of G-MVRM was more stable than other Alphas I’ve flown.

    The front brake was, frankly, disappointing, so much so that I’m inclined to think the unit on test aircraft was not working to its full capacity. The crude tyre brake used on older Mainair machines was both cheaper and more effective. A drum brake is normally better than this, so I’ll give G-MVRM the benefit of the doubt here.

    But let’s get into the air. The first thing which must be said is that the Alpha wins top marks for climb rate: with a three-blade prop and a 462, the Alpha really points skywards when you give it full throttle, achieving its best figures at around 45 mph. Dual it’s good, solo, it’s very good!

    I was especially eager to explore the stall as Mainair machines have in the past had a heavier stall than comparable two-seaters. By heavier, I mean that there’s less feedback of the onset of stall and when it happens it happens very quickly. This characteristic was particularly noticeable on the Alpha’s predecessor, the Flash 2. I was pleased to find that the Alpha has been purged of such ill manners: the stall is now much better, with plenty of rearwards pressure on the bar at the inception. True, the aircraft was doing a healthy 70 mph indicated before it started to recover but l suspect that the setup of the test aircraft was partly responsible for this, with the luff lines set on the long side to keep the pitch light. Generally, the Alpha feels like a Flash 2 with the bite taken out of it, giving much more mellow handling while retaining a high lift coefficient.

    Hands off, G-MVRM flew at 60-65 mph indicated in light turbulence — too fast for my preference as it made the roll heavy unless speed was reduced by pushing out slightly. On a turbulent cross-country I would find this tiring as an aircraft rigged faster than it wants to be accentuates the bumps. I know from previous Alphas that roll control is much lighter if they are rigged slower, something which of course can easily be achieved by simple tuning. I’ve always believed in tuning for handling rather than speed and this philosophy is particularly valid for the Alpha because this wing, like previous Rashes, is very heavy in roll near the stall and generally requires a greater degree of pitch/roil co-ordination from the pilot than some other flexwings.

    By modem standards the Alpha is not especially fast, but it is fast enough. We managed 75 mph with no bother but anything more was uncomfortable, especially in turbulence. The Alpha’s speed range is admirably suited to the average pilot and Mainair was absolutely right not to sacrifice lift coefficient for out-and-out speed.

    On landing, the rear suspension really comes into its own, damping out the impact and making merely average landings look quite classy. The flare is better than previous models, although the approach speed still needs to be kept fairly high.
    [/1][2]

    [/2][4]
    Conclusions
    [/4][1]
    It’s easy to understand the appeal of the Alpha for the long-distance cross-country pilot. Lifting ability is good,
    [/1][2]

    [/2][1]
    The very roomy cockpit has well thought out foot controls and plenty of stowage room.

    Nosewheel design uses a gas strut, a drum brake, and one-piece wheel.

    stowage and fuel capacity are excellent and the styling very attractive. Also, the rear suspension is excellent for taking off in long grass, though I still wonder about those gas dampers. Moreover, Mainair’s unrivalled selection of extras — anything from a ballistic chute to navigation aids — makes for true one-stop shopping.

    Debits are mainly confined to roll control: the Alpha deserves improvement in this area. I’d also feel happierwith more clearance between prop and rigging.

    To summarise, the Alpha is a well-balanced cross-country machine. It’s light years away from the early tnkes produced by the microlight industry — indeed, it makes you wonder what we’ll be seeing in another ten years. It is not, however, a machine which lends itself well to tweaking. If you buy one, keep it and fly it in the manner which the factory intended. Thus respected, it should reward you well.

    Keith Vinning.
    [/1]

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    • #3
      Flight Test

      Thanks kieth for posting the F2a flight test been looking for one for some time, do you know if that was the one from MF from some years back.

      Nick Axworthy.
      "When once you have tasted flight...you will forever walk with your eyes turned skywards..."

      https://www.youtube.com/user/nickjaxe/videos.

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