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A TOP OF THE LINE 15M RACING CLASS GLIDER


The ASW 27 is a high performance glider for the FAI-15m-class (racing class), of the latest technology. This technology, while following from the successful ASW-24, is a significant step forward in airfoil design. The wing of the '27 is very small, yet due to a very high CL, it is a notably successful climb optimised sailplane!

The technology advances learned in the construction of the ASW-24 were very useful in design of the ASW-27. Namely we wanted a small wing (carbon) which climbs "better than most" with improved handling, safety, and performance.

What we learned from the '24 regarding boundary layer control led us to believe that we could move the trip line back onto the control surfaces and still be "practical". AS is the only builder using BLC this far back.. Next the wing root/ fuselage junction were modified. The wing has a "cuff effect" on the inner meter which looks like there is a double dihedral when sighting the leading edge. This is actually a modification of the area from the spar to the leading edge for the first meter from the root. This change addresses the dilemma a designer faces at the wing root junction. As a glider increases speed, drag at the junction of the wing/ fuselage becomes steadily worse. This modification significantly improved this problem. AS is the only builder to do this expensive mod.

Our many loyal ASW-20 customers have always demanded handling characteristics in a '27 similiar to the famous '20. One side benefit of the new wing composite technology available for the '27 yielded flexible wings. The 27 handles beautifully. The roll rate is very fast, feel is excellent, and the famous "soft ride" of flexible wings is back! Again this feature is unique to AS in the current 15 meter designs.

Another major difference between the ASW-27 and our competitors is the design philosophy of the wing planform. The '27 was designed with no compromises regarding span extensions. The possible performance gains available in the "rarified atmosphere" of 48-1 L/D in 15 meter span are very small and difficult to find. The '27 designers admitted this early and eliminated the possibility of multiple spans in the design. this had many benefits in airfoil drag, panel weight, panel flex, and climb performance with a small wing area. This is a major difference between our design and our competitors. We say that no compromises are possible if max performance is needed. They say you can have it both ways. You, the customer get to decide.

The cockpit is another major change compared to our ASW-24 design. The narrow wing chord at the root enables us to move the seat position aft significantly. We estimate an increase in cockpit room of about 3 inches due to this change. Our little glider now has one of the roomiest cockpits available!

Cockpit safety- the Cockpit design of the ASW-27 is further modified from the OSTIV award winning ASW-24. Addition of polyethelene fibers has lightened and "softened" the nose slightly which increases the chances of the nose protecting the pilot's feet in a crash. The nose is lighter and safer than the earlier ASW-24.

The production ships are an empty weight of about 235 KG. with a small wing area of 9m2, the wing loading can go to 55.6 KG/M2 at 500 KG gross weight. This is slightly heavier max wing loading than our competitors and we are pleased to claim a performance advantage when flying in strong conditions at full gross weight. The ship climbs as well as it's competitors at max gross then out glides them!

The flaps and divebrakes are another stand out feature. The '27 has triple panel divebrakes and 44 degree landing flaps. the flap mixer from Schleicher is a truly unique feature often overlooked by buyers. We alone offer control of flaps and ailerons such that they work in concert in positive and negative settings, but also allow normal aileron settings and therefore normal roll rate while flaps are extended all the way to 44 degrees. This feature is only available on Schleicher gliders.

The above allows the '27 to land shorter than it's competitors. Once on the ground the large wheel and Disk brake further reduce the ground roll. Again this is exclusive to AS and significantly increases safety. The ASW 27 not only stands out for its excellent flight characteristics, but also for it's comfortable features.

FEATURES

  • Sprung landing gear with large 5" wheel
  • Hydraulic disc brake
  • Tail wheel
  • Instrument panel hinging upwards with the canopy
  • Nose and C.G. tow release coupling
  • In flight adjustable back rest with integrated head rest
  • Safety harness with quick-release center lock
  • Battery storage space in the baggage compartment (designed to withstand 25G's!) and in the fin

DESIGN SPECIFICATION

Glider of fiber-composite construction, midwing with T-tail. Automatic connections for all controls ( aileron, flaps, airbrakes and elevator)..

FUSELAGE

Monocoque fuselage of fiber-composite structure (CRP, Aramid, Polyethylene and GRP) with roomy safety cockpit.

In flight adjustable rudder pedals.

TOST C.G. combi tow release coupling, covered in flight by the landing gear doors, and TOST aero tow release coupling in the fuselage nose.

Rubber-shock-mounted, retractable landing gear, using a large 5.00-5 wheel, installed in a box which is sealed and airtight from the fuselage interior.

Hydraulic disc brake which is connected to the airbrake lever.

Pneumatic tailwheel 210 x 65.

Optimum cockpit ventilation through intake in the fuselage nose with continuously adjustable outlets, one on the front canopy frame and the other through a directionally adjustable airnozzle on the right side of the cockpit wall. Cockpit ventilation is so good most pilots almost never open the side window.

CANOPY

The full-vision, gas-spring assisted canopy (on the left side with sliding window) is hinged at the front. Tongue and groove type sealing for the canopy frame and a specially shaped rear frame section for the purpose of a safe emergency jettison. The canopy eject mechanism is a significant safety improvement over older designs and current competitors. A single pull on the eject levers jettisons the canopy instantly by automatically lifting the front into the windstream and hinging the canopy at the rear in emergencies.

WATERBALLAST

Waterballast is provided through water bags in the wings. They fill and dump through faired ports in the underside of the wings. The bag location within the wing is again unique to Schleicher. The bags are located almost on the CG making a tail tank unnecessary for CG adjustment. Ballast capacity of about 30 gallons in wings is possible. This is further assisted by a 9.25 gallon water tank located in the fuselage above and behind the main spar.

BOARD EQUIPMENT AND ACCESSORIES

Static pressure vents (for the A.S.I.) in the fuselage tail boom left and right. Pitot, Static pressure and TE-compensation through 3-way-nozzle (multi-probe)in the fin. VHF antenna in the fin. One battery storage facility in the fin and one countersunk battery box in the baggage compartment; depending on the pilot mass the optimum battery installation location will be chosen. Storage space for taking up one 31 oxygen bottle in the right of the main bulkhead. Consoles on the canopy frame left & right for possible fixing of cameras. Removable and adjustable backrest with integrated parachute pan and forward hinging head rest which is covered by lambskin. Backrest adjustment in three positions; screws on bottom end; upper end adjustable in flight by eccenter winch-handle. Lambskin for seat. 4-part safety harness (Gadringer) with quick-release lock.

WING

Cantilever, two-part double-tapered wing planform with latest laminar airfoil; when high speed setting is selected there is laminar airflow at the wing underside beyond the control surface gaps. The airfoil was developed for the ASW 27 design upon specific directions by SCHLEICHER at the Institute for Aviation and Aerospace Technology of the T.H.Delft and tested in their wind tunnel. The airfoil of the outer wing has been modified for detachable winglets using the latest airfoil design. The wing surface is a sandwich of carbon fiber / plastics with a hard foam core; wing spars with carbon flanges. Triple-paneled metal airbrakes on the wing upper surface, in sealed compartments with spring cover plates.

Pushrods sealed by bellows. The wing assembly is straightforward with a conventional tongue and fork spar extension secured with cylindrical main pins. Extremely light-weight wing (approx. 58 kg for each wing including water ballast bag). Control surface gaps on the wing upper and under side sealed by plastic tape. Blow turbulators on the under side of the ailerons and flaps.

TAIL UNIT

T-tail (elevator with stabilizer) with low-drag airfoil, developed especially for the ASW 27 project by the T.H.Delft. Control surface gaps on both sides sealed with plastic tape. And turbulators on both sides in front of the control surface axis. Stabilizer in CRP-sandwich-construction. Vertical fin in GRP-Aramid-construction because of VHF-antenna radiation. Elevator and rudder are new-technology sandwiches of Aramid fiber / plastics with a hard foam core; ailerons and flaps are of CRP monocoque construction which gives extremely light and stiff control surfaces.

CONTROL CIRCUITS AND FITTINGS

Aileron, elevator, flaps, and airbrakes are actuated by pushrods running in anti-noise ball-bearings, and use automatic connections at the assembly joints. The rudder is actuated by stainless cables which run in Polyamid tubings. Infinitely variable trim, lockable by a stick key. All control surface hinges of the wing and of the horizontal tail unit use needle bearings or low-maintenance plastic bearings. The actuating levers and bellcranks are fitted with ball bearings and precise uniball-joints. This provides the lowest possible actuating forces for the pilot and guarantees comfortable, non-fatiguing flying. The fittings are welded steel and milled or turned Duraluminium respectively.

TECHNICAL DATA
Model ASW 27
Airworthiness substantiation according to JAR-22, category U, and according to the LBA-substantiation-requirements for gliders made from fiber composite materials.

Use: Training and performance flights. Competition flights in the FAI 15 m Class. Cloud flying and semi-aerobatics.

Span Incl. winglets 15.00 m (49.22 ft)
Wing area 9.00 m2 (96.88 ft2)
Aspect ratio 25.00
Fuselage length 6.55 m (21.49 ft)
Cockpit height 0.80 m ( 2.62 ft)
Cockpit width 0.64 m ( 2.10 ft)
Height at the tail unit 1.30 m ( 4.27 ft)
Wing airfoils DU 89-134/14 and DU 92-131/14MOD
Empty mass Including minimum equipment approx. 235 kg ( 518 lb.)
Flight mass max. 500 kg (1102 lb.)
Mass of one wing approx. 58 kg ( 128 lb.)
Wing loading max. 55.56 kg/m2 ( 11.38 lb/ft2)
Wing loading min. approx. 32.80 kg/m2 ( 6.7 lb/ft2)
Watterballast max. 165 1 (43.59 US.Gal.)
Useful load max. 130 kg ( 287 lb.)
Useful load in the pilot seat incl. chute max. 115 kg ( 254 lb.)

Max. speed 285 km/h ( 154 kts)
Max. maneuver speed 215 km/h ( 116 kts)
For m = 320 kg flight mass:
Min. speed approx. 70 km/h ( 37.8kts)
Min. sink approx. 0.52 m/s ( 102 ft/min)
Best L/D approx. 48 at 100 km/h (54 kts)

Page last modified on November 24, 2012, at 07:00 PM