Aircraft—A device that is used for flight in the air.

Airplane—An engine-driven, fixed-wing aircraft heavier than air that is supported in flight by the dynamic reaction of air against its wings.

FUSELAGE—The section of the airplane that consists of the cabin and/or cockpit, containing seats for the occupants and the controls for the airplane.

WINGS—Airfoils attached to each side of the fuselage and are the main lifting surfaces that support the airplane in flight.

EMPENNAGE—The section of the airplane that consists of the vertical stabilizer, the horizontal stabilizer, and the associated control surfaces.

CONVENTIONAL LANDING GEAR—Landing gear employing a third rear-mounted wheel. These airplanes are also sometimes referred to as tailwheel airplanes.

Nacelle—A streamlined enclosure on an aircraft in which an engine is mounted. On multiengine propeller-driven airplanes, the nacelle is normally mounted on the leading edge of the wing.

Biplane—An airplane that has two main airfoil surfaces or wings on each side of the fuselage, one placed above the other.

Airfoil—An airfoil is any surface, such as a wing, propeller, rudder, or even a trim tab, which provides aerodynamic force when it interacts with a moving stream of air.

Monoplane—An airplane that has only one main lifting surface or wing, usually divided into two parts by the fuselage.

Truss—A fuselage design made up of supporting structural members that resist deformation by applied loads.

Monocoque—A shell-like fuselage design in which the stressed outer skin is used to support the majority of imposed stresses. Monocoque fuselage design may include bulkheads but not stringers.

Semi-Monocoque—A fuselage design that includes a substructure of bulkheads and/or formers, along with stringers, to support flight loads and stresses imposed on the fuselage.

HUNG START - In gas turbine engines, a condition of normal light off but with rpm remaining at some low value rather than increasing to the normal idle rpm. This is often the result of insufficient power to the engine from the starter. In the event of a hung start, the engine should be shut down.

HOT START - In gas turbine engines, a start which occurs with normal engine rotation, but exhaust temperature exceeds prescribed limits. This is usually caused by an excessively rich mixture in the combustor. The fuel to the engine must be terminated immediately to prevent engine damage.

TURBINE ENGINE HOT/HUNG START
A hot start is when the EGT exceeds the safe limit. Too much fuel entering the combustion chamber or insufficient turbine rpm causes hot starts. Any time an engine has a hot start, refer to the AFM, POH, or an appropriate maintenance manual for inspection requirements.

If the engine fails to accelerate to the proper speed after ignition or does not accelerate to idle rpm, a hung start has occurred. A hung start may also be called a false start. A hung start may be caused by an insufficient starting power source or fuel control malfunction.

The agency for privatisation of the Federation of Bosnia and Herzegovina has confirmed that it has received only one offer for the purchase of 49% of the national airline of the country – B&H Airlines. The tender for the submission of offers was closed yesterday at 16.00CET however the agency has stated it will accept offers sent by mail that arrive in the next 3 days as they could have travelled longer than expected and arrived late as a result. The Agency has stated it is disappointed as many announced they would compete in the tender including Croatia Airlines, MyAir from Italy and Turkish Airlines. It is expected that the offer submitted is a joint bid from the Islamic Bank of reconstruction and development and Royal Jordanian Airlines, the national airline of Jordan.

The best offer, which in this case can only be the one submitted, will be revealed in 30 days (September 29) while final talks between the purchasing party and the government will be held on October 30.

Some numbers from Javafoil using the Drela approximation method (Xfoil after 1991):



NACA 66-020

Parameters: Length 6 meters, diameter from thickest point 1.2 meters:

α Re Cl Cd Cm 0.25 TU TL SU SL L/D A.C.
[°] [-] [-] [-] [-] [-] [-] [-] [-] [-] [-]
0.0 11.60E6 0.000 0.00709 -0.000 0.623 0.623 1.000 1.000 0.000 0.380

So estimated Cd for the fuselage is 0.00709. Doors, antennas, landing gear door, etc. will make it worse.

Bugs and dirt on the fuselage surface and the results becomes:

NACA 66-020

α Re Cl Cd Cm 0.25 TU TL SU SL L/D A.C.
[°] [-] [-] [-] [-] [-] [-] [-] [-] [-] [-]
0.0 11.60E6 0.000 0.01212 -0.000 0.625 0.625 1.000 1.000 0.000 0.380

NACA 66-030 (engine nacelle variant of the laminar body)

m/S = 1
α Re Cl Cd Cm 0.25 TU TL SU SL L/D A.C.
[°] [-] [-] [-] [-] [-] [-] [-] [-] [-] [-]
0.0 11.60E6 0.000 0.00775 -0.000 0.605 0.603 1.000 1.000 0.000 0.456

Cd = 0.00775

With NACA 66-025 the fuselage pod length drops to 4.8 meters.



NACA 66-025

m/S = 1
α Re Cl Cd Cm 0.25 TU TL SU SL L/D A.C.
[°] [-] [-] [-] [-] [-] [-] [-] [-] [-] [-]
0.0 9.28E6 0.000 0.00812 -0.000 0.612 0.612 1.000 1.000 0.000 0.417

Cd = 0.00818

Conclusion: All of these pods provide (according to simulation), a low drag coefficient.

Equivalent drag area for NACA 66-025 assuming body diameter of 1.2 meters:

0.00818*(0.6m*0.6m*3.14159) = 0.00925 m^2 (=0.0823 sq ft)

Hmm. did I calculate correctly? Somehow looks quite small.

Serbian media have responded to the website airlinequality.com which ranks airlines from 1 to 5 stars depending on levels of service and other factors influencing the airlines operations. Although the rankings have been available for more than 4 years, as a Serbian tabloid discovered the website, which is well known amongst aviation fans (website), other more distinguished newspapers picked up the story.

Jat commented on the rankings saying it has motivated them to improve services. The Serbian national airline joins airlines such as SAS, Canadian Airlines, and Iberia and also EX-YU airlines Croatia Airlines and Adria Airways in the 3 star ranking. Jat Airways released a statement saying that “the airline feels proud of its ranking having in mind the extreme difficulties it had faced in the past 17 years. Because of the rankings we will particularly focus on improving customer service”. Jat’s rankings in detail can be seen here.

MAT Macedonian Airlines has received a 2 star rankings while B&H Airlines and Montenegro Airlines have not received rankings as yet. According to the website rankings are reviewed annually. For a full rankings review click here.

I have a bit evolved set of requirements for an aircraft concept to present. They are now as follows:

- safe
* 2 engines
* 2 fuel systems
* 2 propellers
* non-stallable
* non-spinnable
* double avionics
* two batteries
* two electrical systems
* moderate stall speed (<=55 kts)
* good brakes
* good tires and landing gear that does not break from few bounces
- economical
* very low fuel consumption
* must run on autogas or diesel oil
- at least 2 places with side by side seating, in comfort (enough space in cockpit, a lot more than in a Cessna)
- very long endurance
- capable to high altitude flight
- best glide ratio speed as high as feasible (enabling cruising at L/D max).
- very high best L/D ratio (>=1:25)
- low minimum sink rate
- relatively low power required to keep in level flight
- low drag utilizing extensive laminar flow in the fuselage and wings
- lightning strike protection (copper mesh installed to the whole aircraft)
- utility category (+4.4/-2.2G)
- positively stable in all flight conditions (suitable for IFR flight)
- speed brakes / spoilers
- ballistic recovery chute
- strong roll cage around the cockpit, exceeding the current FAR23 requirement at least with factor of two
- keeping aircraft CG on correct place do not require using ballast (no matter if there are two or one person sitting on front seats)
- aircraft can be parked without anyone sitting on it on its normal upright position
- aircraft shall look stylish and out-of-this-worldish
- surface finish has to be smooth
- large enough control panel for fitting IFR instruments (Large EFIS screen + analog backup instruments)
- good visibility outside
- rudder trim
- aileron trim
- elevator trim
- using aircraft systems has to be simple and all procedures has to be very simple and easy to memorize (aircraft shall not be a checklist-machine)

Summary: Different-looking composite aircraft that incorporates extensive laminar flow, does not stall or spin and that you can fly from Europe to Oskosh and back with ease and with peace of mind. Complies or exceeds with FAR23.

The three new MD NOTARS as seen at Christchurch.

ZK-HBC4 c/n LN018, as seen at Heli-Maintenance today.

ZK-HCZ 4. c/n LN106, at Skysales on 29-05-2008

ZK-HYY4 c/n LN107 (not yet registered) at Skysales on 06-07-2008

ZK-HYY & ZK-HCZ as seen today at Skysales.

The bosses signature (Lynn Tilton CEO MDHC) inside the cockpit of ZK-HYY.