Aircraft

JORA Jora

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JORA aircraft is a two seat ultra light airplane, with two seats side by side, and T tail. With nose wheel undercarriage, the wheels of the main undercarriage are braked and the nose wheel is stearable. Suspension is by indio-rubber blocks. The Jora features a deep laminar wing profile.
Construction of the airplane is a combination of laminate and wood, and polyester fabric.

Stall: 24 kt / 28 mph / 45 kmh
Cruise: 76 kt / 87 mph / 140 kmh
VNE: 87 kt / 101 mph / 162 kmh
Empty Weight: 225 kg / 496 lbs
MTOW Weight: 450 kg / 992 lbs
Climb Ratio: 500 ft/min / 3 m/s
Take-off distance (50ft obstacle): 260 ft / 80 m
Landing distance (50ft obstacle): 230 ft / 70 m

Engine: Rotax 503, 52 hp
Wing span: 10.80 m
Wing area: 115 sq.m
MAUW: 420 kg
Empty weight: 205 kg
Fuel capacity: 45 lt
Max speed: 160 kph
Cruise speed: 140 kph
Minimum speed: 45 kph
Climb rate: 4 m/s
Certification: Tch, D Dan.
Seats: 2
Fuel consumption: 8 lt/hr
Plan price (1998): 930 Fht
Kit price (1998): 80 700 Fht

Jonker JS1 Revelation

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The JS1 Revelation is a high-performance FAI 18-metre Class sailplane, fully-equipped in its baseline standard. An optional jet sustainer system is available. With the introduction of the JS1C variant, there was also the additional option of 21-metre wingtips for an ‘agile’ Open Class sailplane.

The design process of the JS1 Revelation started with development of the main wing aerofoil. After wind tunnel tests together with new technology and research on techniques that might help climbing performance, then after making hundreds of iterations, they ended up with the T12 aerofoil.

To optimize climbing in turbulent thermals the T12 does not have the typical flat top Cl-Alpha curve at high lift coefficients.

T12 characteristics:
Maximum thickness/chord ratio 12.7%
14% camber changing flap
Low drag with extensive regions of laminar flow
Laminar to turbulent transition on the lower surface occurs at 93% where artificial transition is applied for negative flap settings
Transition on the upper surface occurs at approximately 65% for a 0° flap setting and 2° angle of attack
The top surface is smooth at 13.5° with almost 70% laminar flow

Although aerodynamically optimised, there are structural challenges using such a thin aerofoil. At the time the T12 aerofoil was the thinnest main aerofoil used on modern sailplanes.

The aerodynamic design of the wing root reduces separation problems at the trailing edge and optimised overall drag. Six different aerofoils are used in the wing for maximizing the performance of the glider. All are derived from the main T12 aerofoil, optimised at each spanwise station for the specific chord length and Reynolds number. The wingtip aerofoil is designed with an ample lift reserve to help handling characteristics and avoid any tendency for wing drop.

The optimum wing planform has an elliptical lift distribution for minimum induced drag at low speeds, and a small wing area for reduced profile drag at high speed. The wings of the JS1 Revelation have six tapered polyhedral sections along the wing span, with aerofoils based on the T12 aerofoil optimised at each spanwise position for the specific chord length and Reynolds number. The polyhedral also contributes to the handling qualities.

The winglets for the JS1 Revelation were specifically tailored for the wing shape and tip airfoil. For all operational angles of attack, the load on the tip region was kept within limits of the maximum airfoil lift coefficient, for safe handling characteristics. Due to the polyhedral wing configuration of the JS1 Revelation, the last wing panel is already at an angle of 24 degrees which increase the angle between the winglet and wing. This reduces the detrimental 3D flow effects at the junction corner due to super positioning of adverse pressure gradients which causes separation.

Conventional structures (such as the controls and landing gear) were designed using traditional calculation methods, with hand calculations for simple geometries and laminate analysis for simple composite structures. The more complex structures were designed using FEM analysis techniques.

A combination of glass-fibre, aramid (Kevlar) and carbon-fibre is used in the load bearing structure of the JS1 Revelation. The very thin wing section (12.7%) posed a challenge for the designers, especially in the wing root area where the maximum thickness is only 100mm.

All structural design was according to the certification standards set in CS-22 and with a general safety factor of 1.725.

Standard features include a multi wingspan, including 18m wingtips with provision for 21m wingtips, a nose release hook and provision for a belly hook enclosed by main wheel doors, a fixed pneumatic tail wheel (brass or Vesconite), a multi-probe (pilot, static pressure and Total Energy), and two recessed battery boxes in baggage compartment and battery compartment in vertical stabiliser

The cockpit has a gooseneck dynamic microphone attached to canopy frame, tick mounted PTT switch and twin speakers for radio and navigation computer, a radio antenna in vertical stabiliser and provision for Dolba transponder antenna installation inside vertical stabiliser.

Boundary layer control is with blowholes and soft tripping turbulators. Integrated main water ballast tanks (approximately 2 x 90 litres) are in the main wings with automatic coupling and maintenance-free valves. An integrated non-dumpable C.G. water tank is in the vertical stabiliser (for optimum C.G. when compensating for pilot and equipment)

Triple-panel upper-surface airbrakes are fitted and the retractable undercarriage has elastomeric shock absorbers. Hydraulic disc brake are activated by full aft travel of airbrake handle.

Jonker Sailplanes selected the M&D Flugzeugbau TJ42 jet turbine engine as an option.

Finite Element Modeling (FEM) allows for the whole structure to be represented as a wire frame of cells or elements called “the mesh”. Loads can then be applied to the mesh and the stresses calculated at each point. The result is a colorful representation of the stress condition throughout the structure. This shows exactly where the structure needs strengthening and where weight can be saved. The figure below shows the stress condition in the front and aft fuselage due to a load on the tail, and a high-g pullout maneuver.

In March 2010 the JS1 Revelation gained its official certification by the South African Civil Aviation Authorities (SACAA). With SACAA Type Certification to CS-22 and with an SACAA ICAO- compliant Certificate of Airworthiness the JS1 Revelation should be able to be flown without restriction in any ICAO-signatory country.

However JS recognises that EASA (and its predecessor, JAA, and the German LBA) are widely acknowledged as the experts in glider certification and that it is important to gain EASA Type Certification (TC) or Type Validation (TV) of the JS1 Revelation, both for market confidence and to enable local registration of the JS1 in Europe. Local registration would allow local maintenance procedures to be applied.

JS and SACAA have been in discussion on how to best proceed with EASA TC/TV. A full EASA TC exercise would require repeating all ground and flight tests with EASA witnesses and re-submitting every report and analysis for EASA scrutiny. This would be unnecessarily time-consuming, expensive and inefficient as it would completely ignore everything done for the SACAA Type Certification. This would be inconsistent with the advice provided by EASA to SACAA and JS, namely to gain local South African Type Certification before presenting this to EASA.

An EASA Type Validation exercise allows EASA to take advantage of the tests, reports and analyses already accepted by SACAA – while at the same time reserving the right to require extra information for any areas of special interest or concern. However in order to use a Validation process (rather than a full Certification process) it is necessary to establish a Working Arrangement between SACAA and EASA – simply a legal framework to allow EASA to accept SACAA findings on the basis that SACAA have followed a robust and rigorous process.

For the SACAA, establishing a Working Arrangement with EASA is part of a longer term strategy to advance the worldwide credentials of SACAA as a competent professional airworthiness authority. In December the Director of Civil Aviation, SACAA formally requested discussions with EASA with the aim of setting up a Working Arrangement for EASA Type Validation of the JS1 Revelation.

This was a major step forward for Jonker Sailplanes; to have the direct involvement and support of the SACAA at the highest level for EASA Type Validation.

ICAO Type Certificate Details
Manufacturer: Jonker Sailplanes cc
Type Certificate: J15/12/550
Issued by: South African Civil Aviation Authority
Model: JS1-A “Revelation” JS1-B “Revelation”
JS1-C 18 “Revelation” JS1-C 21 “Revelation”
MCTOW 600 kg (with water ballast) – JS1-A, JS1-B, JS1-C 18
437 kg (without)
720 kg (with water ballast) – JS1-C 21
520 kg (without)
Max. No. of Seats: 1

Type Acceptance Certificate No. 11/21B/25 from the NZ CAA was granted on 21 November 2011 to the Jonker JS1-A and JS1-B based on validation of SACAA Type Certificate J15/12/550.

The Jonker JS1-A and JS1-B are single-seat 18m class sailplanes with winglets, water ballast provisions, full-span flaperons, upper-surface airbrakes, constructed from composite materials. The configuration includes a shoulder wing, T-type empennage and retractable main landing gear. The JS1-B is identical to the JS1-A except for a smaller tailplane and tail surfaces and is the main production model after s/n 004.

The Jonker JS1-A and JS1-B sailplanes are the first indigenous aircraft Type Certificated
by the South African Civil Aviation Authority.

The JS1-C models are identical to the JS1-B except the outer wing is removable, with two different span wing tips available, 18m and 21m. The JS1-C has been the standard production model since s/n

  1. The JS1-C 21 has wing-tip water tanks and an increased maximum weight, but is not eligible for cloud flying or basic aerobatics.

ICAO Type certificate:
SACAA Type Certificate J15/12/550 issued 12 March 2010
SACAA Type Certificate Data Sheet J15/12/550 Issue 4.0 dated 24 May 2013
JS1-A, JS1-B models approved 12 March 2010
JS1-C 18, JS1-C 21 models approved 23 May 2013

Airworthiness Limitations:
The airframe has a specified service life of 12,000 hours, and requires special inspections at set
intervals to reach it.

JS-21 18m
Wingspan: 18m / 59.06 ft
Wing area: 11.20 sq.m / 120.56 sq.ft
Aspect ratio: 28.8
Fuselage length: 7.165m / 23.51 ft
Fuselage height: 1.32m / 4.33 ft
Max weight: 600 kg / 1323 lb
Wing loading (w/70kg pilot): 35.3 kg/sq.m / 7.23 lb/sq.ft
Max wing loading: 53.6 kg/sq.m / 10.98 lb/sq.ft
Best glide ratio: 1-53
Best glide speed at MAUW: 120 kph / 65 kt
Best glide speed at 450 kg: 100 kph / 54 kt
Min sink rate: 0.50 m/s / 100 ft/min
Vne: 290 kph / 157 kt
Rough air speed: 203 kph / 110 kt
Flight loads at Vra: +5.3 / -2.65 G

JS-21 21m
Wingspan: 21.00 m / 68.90 ft
Wing area: 12.27 sq.m / 132.07 sq.ft
Aspect ratio: 35.9
Fuselage length: 7.165m / 23.51 ft
Fuselage height: 1.32m / 4.33 ft
Max weight: 720 kg / 1587 lb
Wing loading (w/70kg pilot): 33.8 kg/sq.m / 6.92 lb/sq.ft
Max wing loading: 58.7 kg/sq.m / 12.02 lb/sq.ft
Best glide ratio: 1-60
Best glide speed at MAUW: 120 kph / 65 kt
Best glide speed at 450 kg: 100 kph / 54 kt
Min sink rate: 0.48 m/s / 95 ft/min
Vne: 270 kph / 146 kt
Rough air speed: 203 kph / 110 kt
Flight loads at Vra: +5.3 / -2.65 G

Jongblood Primary

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Mike Jongblood of southern California designed and built this single-seat, primary glider in 1966, with assistance from Hugh Knoop. The design was original and includes an original airfoil design as well, designated as a Jongblood II section.

The aircraft is built from wood and covered in doped aircraft fabric covering. The glider has a detachable pod to cover the pilot or can be flown open cockpit. It has a constant chord wing with a 4 ft (1.2 m) chord and a 32.5 ft (9.9 m) span. The wing features dual parallel struts and jury struts, but has no spoilers or other glidepath control devices. The tailplane is also strut-braced. Unlike most earlier primary glider designs that land on a fixed skid, this aircraft has a fixed monowheel.

The Primary had accumulated over 200 auto-tows and seven aerotows, along with nine hours of flying time, by the end of 1968 and by 1983 had flown 22 hours total. It had flown a single three-hour flight and had recorded a height gain of 8,000 ft (2,438 m).

The sole example constructed was reported as “in storage” in 1983. In May 2011 it was still on the Federal Aviation Administration registry listings, although its registration had expired on 31 March 2011.

Wingspan: 32 ft 6 in (9.91 m)
Wing area: 125 sq ft (11.6 m2)
Aspect ratio: 8:1
Airfoil: Jongblood II
Empty weight: 270 lb (122 kg)
Gross weight: 450 lb (204 kg)
Maximum glide ratio: 8:1 at 30 mph (48 km/h)
Crew: one

Jones PJ-1

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The Jones PJ-1 was started around 2005-6 by Bill Cockram, the plans being loosely based on a two seat Monsoon aircraft with an O-200 engine. As he wanted to use a Rotax engine he set about narrowing the fuselage and designing and building his own wings. Cockram became ill and decided he couldn’t finish the aircraft so he gave what he had built so far to Peter Jones and sold him the Rotax 503.

The aircraft is now a single seat that fits into the ultralight class. It is of all wood construction, fabric covered and uses a LongEze canopy. When weighed, the C of G was too far aft so he extended the front, moving the seat forward.

Jones Aircraft Corp

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USA

Jones Aircraft Corp was formed in 1935 by Ben Jones after acquiring rights in D-25 biplane previously built by the New Standard Aircraft Company. Jones built 10 of these in 1938, in factory at Schenectady, New York. In 1937 it introduced the S-125 and S-150 two-seat light cabin monoplanes, powered by Menasco engines.

Jones Sopwith Pup

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Wes Jones discussed the feasibility of building a full-scale Sopwith Pup with Robert Baslee in 2005. They drew the major components on a dinner napkin later acquiring a set of drawings from Replicraft.

Earnest construction began in December, 2005. The plan was to build a Pup that for all outward appearances would look like an original Pup. There were some mandatory considerations, bank account, settling on a VW engine, instead of a preferred Rotec Radial. The Replicraft plans were used for placement of all uprights and longerons, so the dimensions would match the originals, but the materials are more modern and fit the bank account better.

Three-quarter-inch chrome-moly is used for the forward section of the fuse and transitioned to five-eighth-inch aft of the cockpit for the longerons. TIG welding the basic fuse took about a month.

The fuselage and upper wing center section were built of tubular steel and aluminum, respectively.

The wing struts and cabanes were fashioned to the original dimensions out of straight-grain Douglas fir to fit welded fittings like Dennis Wiley’s Early Bird Jenny. The landing gear legs were fashioned from streamline tubing to exact specifications from the original 1916 prints.

A set of horse racing cart wheels were used for rims and inner spoke attachments, and made a set of hubs on the lathe. The hubs gave 8 inches between the spokes at the axle.

By using longer spokes on the outside and shorter spokes on the inside, it got the dished look of the original wheels.

The steerable tailskid was built exactly following the plans of the original, since it was going to be out there for everyone to see. Another reason for sticking with the original skid is that, just like the original, the mains do not have brakes. This helps keep the Pup going straight down a grass field.

The original tailskid worked well until it broke on landing. It was replaced with a piece of wood with conveniently-curved grain.

Wingspars were fashioned from 2-inch .065-wall 6061 tubing. Three-eighth-inch aluminum tubing is used to fashion the ribs la a Graham Lee design. The leading edge uses aluminum sheet metal instead of using nose ribs. Wing-root fittings were copies of the Early Bird Jenny’s root fittings, scaled up for the extra weight. Some expert assistance on rib stitching came from Dallas Shaw, Randy O’Conner and Brad Strohm.

The covering was lightweight Dacron using rhe Stits process from Aircraft Technical Support, since Jim Miller was good friend and neighbour. Since the WW-I originals were just doped on the undersides of the wings and fuse, it was decided to finish those areas using clear Poly-Brush fabric sealer, then adding some tint to the last coat to get an approximate look of old varnish brushed over doped fabric. The markings were done by hand with a brush to approximate what was done in the field back then.

A 2180cc VW engine was built from scratch, using parts obtained from several VW suppliers. It used 94mm cylinders, an 82mm stroker crank, and was set up the compression for 6.67:1 for reliability. Valley Engineering supplied the 2.5:1 propeller speed reduction unit (PSRU), as well as the 96×65-inch prop. Due to some leaning problems with the progressive Weber carb, a single-barrel 34 ICT carb fit the bill better.

A good friend and Dawn Patrol cohort, Rick Bennett, was able to find a correct-size cowling and arrange to have one delivered.

There was some help with the full-scale Vickers machine gun replica on the cowl from Willie Hill, a local expert on getting them to look realistic.

The OK to test-fly it from the local FAA representative, John Walsh, came in October of 2011 and there was only time for six or seven test flights before winter hit hard, so the rest of the time had to be flown off in the spring.

In the air the Pup flies is very stable in normal flight. The four ailerons give a solid feel in roll. Initial timing of the climb rate showed approximately 1200 feet per minute. The climb angle is like a space shuttle launch, although never actually measured.

On takeoff, the tail comes up almost immediately (50 feet) and it gets off the ground in about 150 feet. Stall is around 30 mph and cruise is around 60. The plan to obtain another prop with a 73-inch pitch as soon as funds allow, in order to (hopefully) get the cruise up to around 75-80 mph.

About July, on a normally un-eventful landing, the tailskid wood split at about the halfway mark, leaving no steering and sending the plane into another groundloop. This time, the left upper wing got a slight ding in it due to the hair-raising trip into the woods that immediately followed. Fortunately, two days worth of metal, fabric and painting work sufficed to repair the damage.

A piece of ash with the grain conveniently running along the curve of the new skid replaced it; there have been no problems since.

There has been difficulty keeping the cylinder heads at an acceptable temperature (350 F). Normally it gets about 15 minutes of flight time and temps start to creep up to around 375. Changes with the cooling fins—making extensions to direct the air more smoothly over the heads —and a larger oil cooler with a thermostatically controlled fan may get the temps better.

That old British 10/10 airfoil makes the Pup handle amazingly well.