DESIGN OF AN AIRFOIL FOR
A HIGH-ALTITUDE, LONG-ENDURANCE REMOTELY PILOTED VEHICLE
http://www.rollinghillsresearch.com/Aero_Research/Files/AIAA-2003-0211_NLFairfoil.pdf

NLF1015 coordinates
NLF1015 picture
More accurate picture of NLF1015

The idea of the system comprises of a turbo generator per engine and an additional electric motor behind the tail.

Configuration:
Two gasoline engines, one per wing.
One Brushless DC electric motor, behind the tail, engine size around 15 kW. Does not require any drive shaft because the motor itself is so small and lightweight, that it can be attacted directly to the tail.
Battery that can deliver full power to the electric motor for 3 minutes.
Motor controller for each electric motor.

Possible additions:
Two wing tip turbines, one per each wing tip. Electric motor size ~5 kW.
These can produce power on cruise for the middle pusher motor.

The center pusher motor could drive a unducted fan which would have diameter around 1/3 of the diameter of the fuselage body. See NASA tech paper wake propeller, why. The fan would require adjustable pitch for each blade, so it could be changed from climb condition to cruise condition for the cruise phase (otherwise it would cause drag penalty).

Additional idea:
- the wing tip turbines could be used in case of engine failure for thrust vectoring - one small wing tip engine producing thrust could make the asymmetric thrust condition symmetric without causing drag penalty with deflected rudder.

The blade angle range for constant-speed propellers varies from about 11 1/2 to 40°. The higher the speed of the airplane, the greater the blade angle range.

The range of possible blade angles is termed the propeller's governing range. The governing range is defined by the limits of the propeller blade's travel between high and low blade angle pitch stops. As long as the propeller blade angle is within the governing range and not against either pitch stop, a constant engine r.p.m. will be maintained. However, once the propeller blade reaches its pitch-stop limit, the engine r.p.m. will increase or decrease with changes in airspeed and propeller load similar to a fixed-pitch propeller. For example, once a specific r.p.m. is selected, if the airspeed decreases enough, the propeller blades will reduce pitch, in an attempt to maintain the selected r.p.m., until they contact their low pitch stops. From that point, any further reduction in airspeed will cause the engine r.p.m. to decrease. Conversely, if the airspeed increases, the propeller blade angle will increase until the high pitch stop is reached. The engine r.p.m. will then begin to increase.

Iberia cruises into Zagreb this July

The national carrier of Spain, Iberia, has announced that it will introduced seasonal summer flights from its base at Madrid’s Barajas Airport to Croatia’s capital Zagreb. The new flights should commence on the 4th of July and will cease at the end of the 2009 summer season in late October. Flights will operate twice a week. Adding to this, Iberia will continue its seasonal summer charters this year from Madrid to Dubrovnik, 3 times per week. A third city in Spain will be connected to Croatia this year as well. Croatia Airlines’ Zagreb to Barcelona line will commence in late March and the low-cost ClickAir from Spain will operate daily flights to Dubrovnik from Barcelona.

During 2008, 166.000 tourists from Spain visited Croatia, an increase of 10% compared to 2007. Zagreb Airport is currently served by 13 airlines. This will increase during the summer months.

Brian Wigley's Cessna 182E ZK-WKK (c/n 53823) parked outside the Aero Club minus engine.

Cessna 172M Skyhawk ZK-FKS (c/n 63305) of Rick Lucas Helicopters outside the Clubs hangar on Friday (30th). Today (31st) it was on the tie downs, still minus upper engine cowling.

In the Club workshop was the Cessna 172N Skyhawk ZK-EJQ (c/n 68793) ex Bill Hales of Hanmer Springs. It has just joined the Club lineup (from 09-01-09). Note the CAC emblem near the top of the fin. This edition to the Club fleet is due to a change to the Indian regs that require their NZ (overseas) trained pilots to have had their commercial licence flight test carried out in NZ on an aircraft type that is available in India before their Indian licences can be granted when they get back home. (Does that make sense ?) [anyway I know what I mean]. Seemingly the PA28's are a bit scarce on the ground over there.

The Club had an open day today and ANZ/Eagle kindly supplied this B1900D ZK-EAR2 from mid afternnon for public inspection. Here it has just taxied past the fuel pumps and is about to stop outside the club rooms.

Andy Hopper's Cessna T210N G-SEEK (c/n 64579 ex N9271Y) is currently parked up near the Aero Club at Christchurch.

On the port side fin fillet is this map showing progress.

Learn more on http://www.earthrounders.com/

Yesterday (Friday 30-01-2009) I called into the Canterbury Aero Clubs engineering workshop to see what progress had been made on assembling the new Archer III's. The answer was - None.

Today (Saturday 31-01-0-09) the Archer ZK-EQP has been moved out of the way and N6073E is having the last vestiges of its US markings removed while the wings and tailplane are being attached as you watch (engineer in cockpit working on wing attachments). This was registered as ZK-LJJ yesterday.

This burst of activity being the result of yesterdays loss of the Archer ZK-EBW near Lake Ellesmere.

Thanks to the Canterbury Aero Club for permitting me to poke around. It also was an open day today (Saturday) hence the couple wandering around in the background.

After a mad dash home, some brief reflections on Sebring 2009.
---The show was a real shot in the arm for exhibitors who had worried the dreary economic news would sound the toll of doom.
---Instead, enthusiastic crowds on Thursday and Friday both set attendance records for the five year event. Saturday was also well attended. Sunday, typical of previous shows, was less robust.
---Folks brought checkbooks too: at least 15 LSA were sold at the show, but I'll have final numbers once I'm able to poll all the exhibitors.
---Many thanks to the tireless, smiling volunteer staff that helped run the event, and we'll be back next year.

Sport Aviation lives!

Some notes on a young man I was just getting to know at Sebring. Steven Fletcher, a highly respected and well-liked aviation photographer from Great Britain, was killed in the crash of an LSA Sunday morning.
We talked and shared stories about our mutual profession at the show. I liked him immediately for his ready, affable smile and genuineness.
Unsubstantiated rumors point to mis-assembly of the photo ship he was riding in as the cause of the takeoff crash. NTSB was on the scene examining the wreckage, so we won't say more until an official cause has been determined, which will likely be some time.

(update: A reader requesting anonymity emailed with his take on the accident: it was the classic stall/spin crash. He speculates the photo plane was already in flight, paralleling the airplane that was launching from the runway. When the photo plane made a 270 degree turn so the photographer could keep the other plane in view, the inside wing stalled and the photo plane was too low to recover. That would make the crash more likely to have been caused by pilot error rather than mis-assembly. )

There are always lessons to derive from tragedy. Whether the photo mission was, as according to witnesses, rushed, or the crash was caused by pilot error, these things usually happen when there's a conflict between mission urgency and mission safety .
---Those two factors should never be at odds. And guess which one always comes first? (Hint: it's not mission urgency)
---When I brief for photo missions, I routinely say, "Safety is first. If I ask you to do something and you don't feel comfortable about it, tell me. The photo is always the least important thing. "
And if misassembly turns out to be the culprit: Preflight, preflight, preflight, people!
---We’ll remember and miss Steve for his warmth and his fine work. The aviation community mourns his loss. We send our heartfelt condolences to his wife and children.
---The photo of Steve was taken at the show by his friend Ken Godin of Flight Design USA, who has helped set up a relief fund for Steve's family. Please make checks payable to: Steve Fletcher Family Fund

In the US, mail to:
Fletcher Fund
75 Hope Lane
Glastonbury, CT 06033

In the UK, mail to:
Fletcher Fund
Key Publishing
PO Box 100
STAMFORD PE9 1XQ
UNITED KINGDOM

For direct donations through PayPal
fletcherfund@keypublishing.com

If you have another way you'd prefer to contribute, please contact:
(in U.S.): fletch-fund@composiclean.com
(in U.K.): fletcherfund@keypublishing.com

http://www.freepatentsonline.com/4917332.html
http://www.aiaa.org/content.cfm?pageid=406&gTable=mtgpaper&gID=80452

One of the nicely appointed funplanes at the show was FPNA's Cape Town (the white Valor, below, is the same aircraft with conventional tri- gear). My pal and industry guru Dan Johnson, seen in the right seat above during our photo mission, will do the writeup for a future issue.

I won't deny it: I love this airplane just for it's looks.
---I finally got to ride in the CZAW Sport Cruiser, the airplane I mentioned a couple days ago here, and that I have hankered for a flight in since I first photographed it almost three years ago. This beautiful red and white job drew consistent attention throughout the show. Look for my flight report in a future issue

The engine is started with the propeller control in the low pitch/high r.p.m. position. This position reduces the load or drag of the propeller and the result is easier starting and warm-up of the engine. During warm-up, the propeller blade changing mechanism should be operated slowly and smoothly through a full cycle. This is done by moving the propeller control (with the manifold pressure set to produce about 1,600 r.p.m.) to the high pitch/low r.p.m. position, allowing the r.p.m. to stabilize, and then moving the propeller control back to the low pitch takeoff position. This should be done for two reasons: to determine whether the system is operating correctly, and to circulate fresh warm oil through the propeller governor system. It should be remembered that the oil has been trapped in the propeller cylinder since the last time the engine was shut down. There is a certain amount of leakage from the propeller cylinder, and the oil tends to congeal, especially if the outside air temperature is low. Consequently, if the propeller isn't exercised before takeoff, there is a possibility that the engine may overspeed on takeoff.

An airplane equipped with a constant-speed propeller has better takeoff performance than a similarly powered airplane equipped with a fixed-pitch propeller. This is because with a constant-speed propeller, an airplane can develop its maximum rated horsepower (red line on the tachometer) while motionless. An airplane with a fixed- pitch propeller, on the other hand, must accelerate down the runway to increase airspeed and aerodynamically unload the propeller so that r.p.m. and horsepower can steadily build up to their maximum. With a constant- speed propeller, the tachometer reading should come up to within 40 r.p.m. of the red line as soon as full power is applied, and should remain there for the entire takeoff.

Excessive manifold pressure raises the cylinder compression pressure, resulting in high stresses within the engine. Excessive pressure also produces high engine temperatures. A combination of high manifold pressure and low r.p.m. can induce damaging detonation. In order to avoid these situations, the following sequence should be followed when making power changes.

• When increasing power, increase the r.p.m. first, and then the manifold pressure.
• When decreasing power, decrease the manifold pressure first, and then decrease the r.p.m.

It is a fallacy that (in non-turbocharged engines) the manifold pressure in inches of mercury (inches Hg) should never exceed r.p.m. in hundreds for cruise power settings. The cruise power charts in the AFM/POH should be consulted when selecting cruise power settings. Whatever the combinations of r.p.m. and manifold pressure listed in these charts—they have been flight tested and approved by the airframe and powerplant engineers for the respective airframe and engine manufacturer. Therefore, if there are power settings such as 2,100 r.p.m. and 24 inches manifold pressure in the power chart, they are approved for use.

With a constant-speed propeller, a power descent can be made without overspeeding the engine. The system compensates for the increased airspeed of the descent by increasing the propeller blade angles. If the descent is too rapid, or is being made from a high altitude, the maximum blade angle limit of the blades is not sufficient to hold the r.p.m. constant. When this occurs, the r.p.m. is responsive to any change in throttle setting.

Some pilots consider it advisable to set the propeller control for maximum r.p.m. during the approach to have full horsepower available in case of emergency. If the governor is set for this higher r.p.m. early in the approach when the blades have not yet reached their minimum angle stops, the r.p.m. may increase to unsafe limits. However, if the propeller control is not readjusted for the takeoff r.p.m. until the approach is almost completed, the blades will be against, or very near their minimum angle stops and there will be little if any change in r.p.m. In case of emergency, both throttle and propeller controls should be moved to takeoff positions.

Many pilots prefer to feel the airplane respond immediately when they give short bursts of the throttle during approach. By making the approach under a little power and having the propeller control set at or near cruising r.p.m., this result can be obtained.

Although the governor responds quickly to any change in throttle setting, a sudden and large increase in the throttle setting will cause a momentary overspeeding of the engine until the blades become adjusted to absorb the increased power. If an emergency demanding full power should arise during approach, the sudden advancing of the throttle will cause momentary overspeeding of the engine beyond the r.p.m. for which the governor is adjusted. This temporary increase in engine speed acts as an emergency power reserve.

Some important points to remember concerning constant-speed propeller operation are:

• The red line on the tachometer not only indicates maximum allowable r.p.m.; it also indicates the r.p.m. required to obtain the engine's rated horsepower.
• A momentary propeller overspeed may occur when the throttle is advanced rapidly for takeoff. This is usually not serious if the rated r.p.m. is not exceeded by 10 percent for more than 3 seconds.
• The green arc on the tachometer indicates the normal operating range. When developing power in this range, the engine drives the propeller. Below the green arc, however, it is usually the windmilling propeller that powers the engine. Prolonged operation below the green arc can be detrimental to the engine.
• On takeoffs from low elevation airports, the manifold pressure in inches of mercury may exceed the r.p.m. This is normal in most cases. The pilot should consult the AFM/POH for limitations.
• All power changes should be made smoothly and slowly to avoid overboosting and/or overspeeding.

Adria's CRJ900 soon in Croatia Airlines colours?

Due to a delay in the delivery of Croatia Airline’s new Bombardier Dash8-Q400 the Croatian national carrier is now considering leasing an aircraft from its rival Adria Airways during the 2009 summer season. Croatia Airlines would lease Adria’s CRJ900. This has sparked a major debate in Croatia. Many believe that Croatia Airlines should lease aircraft from the 2 other airlines that call Croatia their home - Dubarovnik Airlines and Trade Air, which could provide an aircraft of similar capacity as the Dash8. Critics believe that leasing an aircraft from Croatia’s arch rival, the Slovenian Adria Airways, and providing them money could only hurt Croatia Airlines and its position as the regional leader, as the airline struggles with major financial losses recorded in 2008. If Croatia Airlines goes ahead with this deal it would pay the Slovenian carrier millions of dollars.

Croatia Airlines management stated that they are surprised and annoyed that these sorts of rumours have been released to the public although they did remind that both Adria and Croatia Airlines are Star Alliance members. The airline says it will lease an aircraft from the company that offers the least expensive plane. The airline also states that both Dash8s will be in the Croatia Airlines fleet this year although the delivery of the aircraft has been slightly delayed. Croatia Airlines already has 2 of the four 76-seat aircraft it has order.

Piper PA-28-161 Warrior III ZK-EBW2 (c/n 2842165) of the Canterbury Aero Club was destroyed by fire late this morning in an incident at Kaitorete Spit (perhaps better known as Birdlings Flat) Lake Ellesmere. The two occupants received only minor injuries when the aircraft was thought to have struck something during a landing on the airstrip there.

Wire strike ??

Once the pilot selects the r.p.m. settings for the propeller, the propeller governor automatically adjusts the blade angle to maintain the selected r.p.m. It does this by using oil pressure. Generally, the oil pressure used for pitch change comes directly from the engine lubricating system. When a governor is employed, engine oil is used and the oil pressure is usually boosted by a pump, which is integrated with the governor. The higher pressure provides a quicker blade angle change. The r.p.m. at which the propeller is to operate is adjusted in the governor head. The pilot changes this setting by changing the position of the governor rack through the cockpit propeller control.

On some constant-speed propellers, changes in pitch are obtained by the use of an inherent centrifugal twisting moment of the blades that tends to flatten the blades toward low pitch, and oil pressure applied to a hydraulic piston connected to the propeller blades which moves them toward high pitch. Another type of constant-speed propeller uses counterweights attached to the blade shanks in the hub. Governor oil pressure and the blade twisting moment move the blades toward the low pitch position, and centrifugal force acting on the counterweights moves them (and the blades) toward the high pitch position. In the first case above, governor oil pressure moves the blades towards high pitch, and in the second case, governor oil pressure and the blade twisting moment move the blades toward low pitch. A loss of governor oil pressure, therefore, will affect each differently.

The turbocharged engine allows the pilot to maintain sufficient cruise power at high altitudes where there is less drag, which means faster true airspeeds and increased range with fuel economy. At the same time, the powerplant has flexibility and can be flown at a low altitude without the increased fuel consumption of a turbine engine. When attached to the standard powerplant, the turbocharger does not take any horsepower from the powerplant to operate; it is relatively simple mechanically, and some models can pressurize the cabin as well.

The turbocharger is an exhaust-driven device, which raises the pressure and density of the induction air delivered to the engine. It consists of two separate components: a compressor and a turbine connected by a common shaft. The compressor supplies pressurized air to the engine for high altitude operation. The compressor and its housing are between the ambient air intake and the induction air manifold. The turbine and its housing are part of the exhaust system and utilize the flow of exhaust gases to drive the compressor.

The turbine has the capability of producing manifold pressure in excess of the maximum allowable for the particular engine. In order not to exceed the maximum allowable manifold pressure, a bypass or waste gate is used so that some of the exhaust will be diverted overboard before it passes through the turbine.

The position of the waste gate regulates the output of the turbine and therefore, the compressed air available to the engine. When the waste gate is closed, all of the exhaust gases pass through and drive the turbine. As the waste gate opens, some of the exhaust gases are routed around the turbine, through the exhaust bypass and overboard through the exhaust pipe.

The waste gate actuator is a spring-loaded piston, operated by engine oil pressure. The actuator, which adjusts the waste gate position, is connected to the waste gate by a mechanical linkage.

The control center of the turbocharger system is the pressure controller. This device simplifies turbocharging to one control: the throttle. Once the pilot has set the desired manifold pressure, virtually no throttle adjustment is required with changes in altitude. The controller senses compressor discharge requirements for various altitudes and controls the oil pressure to the waste gate actuator which adjusts the waste gate accordingly. Thus the turbocharger maintains only the manifold pressure called for by the throttle setting.

Altitude turbocharging (sometimes called "normalizing") is accomplished by using a turbocharger that will maintain maximum allowable sea level manifold pressure (normally 29 – 30 inches Hg) up to a certain altitude. This altitude is specified by the airplane manufacturer and is referred to as the airplane's critical altitude. Above the critical altitude, the manifold pressure decreases as additional altitude is gained. Ground boosting, on the other hand, is an application of turbocharging where more than the standard 29 inches of manifold pressure is used in flight. In various airplanes using ground boosting, takeoff manifold pressures may go as high as 45 inches of mercury.

Although a sea level power setting and maximum r.p.m. can be maintained up to the critical altitude, this does not mean that the engine is developing sea level power. Engine power is not determined just by manifold pressure and r.p.m. Induction air temperature is also a factor. Turbocharged induction air is heated by compression. This temperature rise decreases induction air density which causes a power loss. Maintaining the equivalent horsepower output will require a somewhat higher manifold pressure at a given altitude than if the induction air were not compressed by turbocharging. If, on the other hand, the system incorporates an automatic density controller which, instead of maintaining a constant manifold pressure, automatically positions the waste gate so as to maintain constant air density to the engine, a near constant horsepower output will result.

First and foremost, all movements of the power controls on turbocharged engines should be slow and gentle. Aggressive and/or abrupt throttle movements increase the possibility of over boosting. The pilot should carefully monitor engine indications when making power changes.

When the waste gate is open, the turbocharged engine will react the same as a normally aspirated engine when the r.p.m. is varied. That is, when the r.p.m. is increased, the manifold pressure will decrease slightly. When the engine r.p.m. is decreased, the manifold pressure will increase slightly. However, when the waste gate is closed, manifold pressure variation with engine r.p.m. is just the opposite of the normally aspirated engine. An increase in engine r.p.m. will result in an increase in manifold pressure, and a decrease in engine r.p.m. will result in a decrease in manifold pressure.

Above the critical altitude, where the waste gate is closed, any change in airspeed will result in a corresponding change in manifold pressure. This is true because the increase in ram air pressure with an increase in airspeed is magnified by the compressor resulting in an increase in manifold pressure. The increase in manifold pressure creates a higher mass flow through the engine, causing higher turbine speeds and thus further increasing manifold pressure.

When running at high altitudes, aviation gasoline may tend to vaporize prior to reaching the cylinder. If this occurs in the portion of the fuel system between the fuel tank and the engine-driven fuel pump, an auxiliary positive pressure pump may be needed in the tank. Since engine-driven pumps pull fuel, they are easily vapor locked. A boost pump provides positive pressure—pushes the fuel—reducing the tendency to vaporize.

Jat pilots give all clear for Belgrade – Abu Dhabi line

Tonight at 20.15 Jat Airways’s last flight to Dubai, JU088, will depart returning to Serbia’s capital on Friday afternoon. Not only was the line the longest in Jat’s destination network, it was also the most popular and profitable, with the largest average load factor on any of Jat’s flights. This was mostly due to passengers travelling to Australia from Belgrade (Serbia’s Diaspora) which had excellent connections to 4 Australian and 2 New Zealand cities, with Jat managing to secure special pricing in cooperation with Emirates. However Emirates has recently changed its policy and significantly increased prices for Jat to the point where it is extremely expensive for passengers to travel on this combination. The Dubai based carrier did the same to Croatia Airlines. This new policy might not have been such a good move as Emirates has been left with the largest amount of empty seats to and from Australia in January in the last 5 years.

Jat Airways immediately began work on securing a new connection to Australia and it seems to have found a new partner. It is Emirates’ arch rival Etihad Airways, the national carrier of the United Arab Emirates. The new deal will allow Serbs to travel to and from Sydney, Melbourne and Brisbane via Abu Dhabi to Belgrade, although the airline is rapidly expanding and planning to begin services to Perth. Meetings have taken place between the two carriers in Sydney and in the first week of February will take place in Belgrade. This is when the deal is expected to be officially announced. Jat has expressed an immediate wish to commence services to Abu Dhabi and there is even talk of Etihad code sharing on these flights, although details will be available in early February. Despite a fleet shortage Jat will provide the aircraft for the Abu Dhabi line which will now most certainly commence during the summer season. This news has left pilots and cabin crew in high spirits. Both were extremely angry once they heard that the Dubai line will be closed. The Dubai line benefited pilots due to its long flying hours while cabin crew benefited as this was the only line where they did not immediately return to Belgrade, instead they spent a few days in the ultra-modern city.

Jat resumed services to Dubai in 2002, after more than a decade. Flights were operated via Lebanon’s capital Beirut. Following the assassination of Lebanon’s president and the political instability which took place immediately afterwards Jat decided to operate Dubai via Kuwait. This proved to be a bad move. Jat was unable to secure local passengers from Kuwait to Dubai as it had extreme competition from Kuwait Airways, Emirates and low-cost Jazeera Airways. A year later Jat returned to Lebanon. However once again it was not to be. As the Israel-Lebanon war took place Jat made a decision to permanently reroute its flights to Dubai via Larnaca in Cyprus. This has been by far the most successful stop over destination to Dubai.

The new line to Abu Dhabi will also most likely be operated either via Larnaca or Beirut. More details will be available after next week’s meeting in Belgrade.

A flying visit through Rangiora today found the Cessna 120 N77317 (c/n 11759) has finally succumbed and joined the NZ civil register for Fred Vernon as ZK-XTX as from the 13th. The XTX being applied, and the "N" covered over, in the last couple of days. This is only the second Cessna 120 on our register after ZK-FFK which was listed on 13-09-1983 and is currently with the Vintage Cessna 120 Syndicate of Hamilton.

Above. Mods nearly completed. The Ragwing Aero Special ZK-POP (c/n RWS086) with its engine moved forward to bring the c of g into line and with reshaped cowling.

Below. Taken on 30-03-2005, ZK-POP with is original short Polikarpov style nose.
It has now also gained the Popeye character on its tail.

Above is the Sigma Aircraft Sigma-4 ZK-JRN (c/n 10) coming together nicely and is expected to be at the SAA flyin at Ashburton over Waitangi weekend. This was first registered to Maxim Vassiliev on 24-05-2007. The Sigma ZK-JRC2 previously at Ashburton is now based at Wigram (temporarily) with Hary Devonish -also owner of Hughes 269 ZK-HYQ.

Airborne Windsports Edge X 582 ZK-JOZ2 from the Canterbury Recreational Aircraft Club was outside for me today.

This was built using some parts from ZK-WYN which makes it also ex (parts of) ZK-DUG3.

It seems that X-plane educates aerodynamics, what to expect and think about different things. I was originally saying that I am not so interested in transonic region but rather interested in high altitude. I have been reading about these, but some little things like tinkering with X-plane can cause heureka moments.

And here is what happened:
I have a model of my twin concept in X-plane simulator (obviously, why wouldn't I). So I set in the latest incarnation the engine critical altitude to 50000 ft (which is feasible with two turbos in cascade plus the mentioned electric turbo compounding). I used 110 hp per side (equivalent of Rotax 912ULS equipped with two turbos doing turbo normalization plus intercooler and after cooler).

I was reading Roskam couple of days ago and noticed that the transonic drag is not a problem if the speed is mach 0.2 or below or not that much above that, e.g. 0.3-0.4 is still quite fine. So I was thinking that maybe it doesn't get that high that it would become a consideration.

So so obviously, I put the plane model to climb to 55000 ft with autopilot. I had previously added the mach meter to the hud. I came back checking how it flies after couple of tens of minutes. And oops: mach 0.56 when level at 55000 ft. The IAS was barely 100 kts. TAS was a quite a bit higher.

Then, I was thinking what happens to the Reynolds number. Indeed it gets smaller with altitude increasing. But interesting thing is what really happens, to which number it gets. I verified with atmosphere calculator, that indeed, the interesting Re range for this kind of concept with the AR=14 wing, it becomes 600000 - 1600000. That is _very_ low for an aircraft, which is full size and not a RC-model. So the low Re becomes after all a major consideration.

How a plane with AR=14 flies at 55000 ft? It requires _full_ trim aft (meaning nose high) to get the plane keep level - in this model. It became quite apparent that indeed, the tail volume coefficient is a more major concern at high altitude than at low altitude. And the control authority that felt fine at low altitude was not so fine at high altitude.

So this is what we have:
- High performance low Re airfoil is very necessary
- Cd at high lift coefficient is an important design point, the airfoil needs to be designed so that it gives high L/D at high lift coefficient rather than at low lift coefficient like for example NLF414F is targeting.
- A big tail with long enough moment arm
- Propeller with large diameter and possibly more blades than usual, e.g. 5 blades
- And of course, two turbos, intercooler, aftercooler, generator, battery, electric motor and a shaft between the prop and the engine.

Btw, my model is not yet available for download because it is not perfect, and it has couple of problems. It is very hard to get the splines right with straight sections edited by hand, and e.g. engine nacelles look really terrible at the moment. Anyway, it is a fun way for trying out things in practice.

Croatia, Jat or Adria in 2009?

Currently 3 airlines from the EX-YU region stand in front of all the other carriers and are competing to become the “regional leader” with the largest number of passengers transported. These three airlines are Croatia Airlines (2008 winner), Serbia’s Jat Airways (second placed) and Adria Airways (closely behind Jat in third position). 2009 will be particularly competitive as most carriers in the world are suffering significant losses, both financially and passenger wise. This is why the January 2009 figures will be extremely significant and a good indication of what 2009 holds for the three carriers.

In 2008 Croatia Airlines transported a record 1.87 million passengers, which is 9% greater than in 2007. The largest increase in passengers was seen on international services where 15% more passengers travelled than in 2007, meaning 1.21 million passengers travel internationally on Croatia Airlines. On domestic services a total 543.000 passengers chose Croatia Airlines, 11% more than in 2007. Croatia Airlines charter flights recorded 116.300 passengers. The cabin occupancy stood at 65.2%, an increase of 0.3% compared to last year. Croatia Airlines is likely to win 2009. The carrier hopes it will reach 2 million passengers this year however there is turbulence ahead. The global financial crisis could see a large decrease in tourist travel. During the summer months Croatia Airlines transports most of its annual passengers and makes the greatest profit. This is why Croatia Airlines is uniting with the Croatian Tourism Organisation so a downturn in visitors is avoided. Croatia Airlines’ most important month will be August and could be a good indication if the carrier will have fewer passengers by the end of December when compared to 2008.

Jat Airways transported a total of 1.36 million passengers in 2008, an increase of 4% compared to last year. However in December 2008 Jat recorded a drop in passenger numbers and could potentially lose its silver medal position in 2009 to Adria Airways. The carrier has started a major campaign to increase passenger numbers in January and February by heavily discounting ticket prices to regional destinations. If the airline stabilises by the start of the summer season in March, Jat could see greater passenger numbers. Significant international events to be held in Serbia this year (including the world’s largest sporting event of 2009) could provide the necessary boost but January figures could be a good indication of what is in store for Jat in 2009.


Slovenia’s Adria Airways saw the greatest increase in passenger numbers in 2008 when compared to 2007. It transported a total of 1.3 million passengers, 16% more than in 2007. Cabin occupancy stood at 66%. Adria saw a large increase in passenger numbers from January to June last year because it took over the presidency of the European Union during this period, which increased business travel. This is why these first 6 months of the year will indicate if Adria can sustain these passenger figures without the EU presidency. Adria’s financial results during 2009 could also have an impact on services during the year which could potentially bring in or turn away passengers.

Note: Visit tomorrow to read details about Jat’s new flights to Abu Dhabi

Thanks to the TVNZ news last night for a reminder - The 25th anniversary of the Invercargill floods is going down about now. I was fortunate enough to be working out of Invercagill at the time, although I was away on annual leave at the Gliding championships at Alexandra during the initial event. Our house was on the "hill "at Clifton, so we were not flooded out.
I got back into town on 06-02-1984 and managed to get some photographs of the clean up operations going on at the airport.

The two shots above show the Britten-Norman BN2A-21 F-OCXP (c/n 483) belonging to Montagnat Mining of Noumea being towed back down onto the tarmac . It along with a couple of other aircraft including the Beech 95-A55 Baron ZK-SUN1 and I think a Fletcher had been dragged up on to the stopbanks near what was at the time the H/C (NZ) hangar to escape most of the flood water damage.

Not so lucky were the hangars themselves where some of the aircraft had their noses raised onto boxes and oil drums to try & keep the engines out of the water (with limited success). Above is the Southland Aero Club Piper PA-28-140 ZK-EIC (c/n 7725214) alread stripped to help the drying out process. It went to Hamilton Aero Maintenance for a tidy up and is still curent today around Tauranga.

Cessna 182P Skylane ZK-DYV (c/n 61507) is seen here drying out. It is still current with the same owners.

About to be taken away for remedial action was the Cesna 150H ZK-CXL (c/n 68308) which was syndicate owned. After repairs it went to Rotorua. It is still active, now in the Christchurch area.

One of my favourite machines at the time was this Piper PA-28-235 Cherokee ZK-CIS (c/n 10630). It had its nose raised and you can see the high tide mark runs from about 2/3rd the way up the rudder to about the leading edge of the wing. It is also still current out of Hamilton.

Other aircraft known to have been on the field at the time were Tiger moth ZK-BGP, Cessna 172 ZK-DMH, Piper Hatchets ZK-EIR and ZK-EQI, Fletcher ZK-EFN and ZK-CBD, Piper Cherokee 181 ZK-EDBO, Piper Aztec ZK-DUB, Islander ZK-FFL.

Fewer costs in 2009?

Although a leader in passenger numbers, Croatia Airlines’ losses have doubled in 2008 when compared to 2007. The airline has carefully planned new measures to decrease costs. The Croatian carrier has also mapped out two possible outcomes for 2009, one of which (the optimistic one) would see passenger numbers rise. In 2008 fuel costs have increased the most when compared to 2007 making it the airline’s largest expenditure. Croatia Airlines spent 11 million Euros more than in 2007 for fuel. The airline fears that the global financial crisis and the downturn in global aviation could have a negative impact on the carrier. The airline’s first scenario predicts that the price of crude oil will stabilise at USD 75 per barrel which would allow the carrier to introduce new services to Barcelona and Gothenburg in early June as well as introduce 2 new Bombardier Dash8-Q400s to its fleet this spring. This scenario also predicts that the Croatia Airlines fleet will spend more time in the skies, increasing total flying time by 7%. The airline hopes that over 2 million passenger will use Croatia Airlines in 2009.

The less optimistic scenario sees the negative impacts of the global financial crisis and the effect it could have on Croatia Airlines. The negative scenario predicts that less passengers will want to travel in 2009 and as a result seats on the carrier’s aircraft will be empty. In this case the airline will suspend the 2 new destinations in its network and would delay the arrival of its 4 Airbus A319 order with a possibility to delay the 2 upcoming Dash8s. Every year carries its own surprises and results will be published on the blog when they are released.

Kate invented one day that why the turbo compounding could not be implemented with electric motors, because that way the usually unfeasible gearbox from normal turbo compounding becomes unnecessary and the gearing is instead implemented with the electric motor and the generator where the generator rotates at higher revolutions than the motor that is used to decrease the load the combustion engine sees.

We were in assumption that this was a new invention, but it seems that it has been used in heavy machinery already, e.g. by Catepillar. This in turn also means that it is feasible.

The challenge would be how to place the generator to the shaft of the turbo. Usually turbos do not have a place where to fit the generator but they are closed packages which are not easily modifiable.

The idea would be to increase fuel efficiency with the compounding and increase the shaft horse power without loading the combustion engine anything more. The electric motor could have an additional lithium polymer batter pack which could increase the power even more on takeoff, so the plane would have on critical take off situation somewhat more power than the combustion engine can output, so in other words, for example getting 80 hp out of a 60 hp HKS700E.

This would result that using impossibly small engine power would become a possibility in a wider variety of airframes. On a twin 2 x 80 hp is a lot more than 2 x 60 hp, single engine performance on 60 hp is very poor in any case without any tricks done to increase the power temporarily.

A quite small lithium polymer battery pack would be enough since assuming 300 fpm climb rate on a single engine, this results 3 minutes to 1000 feet AGL where it should be safe to turn back to the runway and perform landing even with a very low power output of a single engine. So it would be well enough for the extra power from the battery pack last only for 3 minutes. This kind of battery pack would not be that heavy, and the brushless DC electric motor is also pretty lightweight.

Any comments on this?

Airport City Belgrade

Serbia’s capital Belgrade joins an elite club of cities to build the EUROCONTROL centre for aviation training. Only Austria, the Netherlands and the United Kingdom have the prestigious EUROCONTROL aviation centre. All countries from the region supported EUROCONTROL’s decision to place the centre in Belgrade including Croatia, Macedonia, Bosnia and Herzegovina, Montenegro, Romania and Bulgaria. Crew and future pilots from these countries will be travelling to Belgrade in order to satisfy their training needs. This latest development makes Serbia the most developed country in the area of aviation in the EX-YU region.

The EUROCONTROL centre will open in April this year and will be located in the exclusive newly constructed Airport City in Belgrade, where Belgrade’s old airport once stood. The centre will give the opportunity for future pilots to attend various seminars and lectures taught by renowned international flight instructors. EUROCOTNROL has had extremely good relations with Serbia and Belgrade. If the European Union passes a new law which would see airspace across Europe controlled only by a few agencies, EUROCOTNROL has suggested that Belgrade be the one for controlling airspace in the Balkans. Belgrade currently controls Serbia’s and Montenegro’s airspace as well as parts of Bosnia and Herzegovina’s airspace.

My take on a well photographed manoeuvre, taken at Wings Over Wairarapa.

Still pretty spectacular though!

When I was working through Cairns in 1977 one of the pics I took was of this Piper PA-34-200 Seneca VH-MEP (c/n 34-7350165). It was first registered in Australia on 22-05-1973.

Today 26-01-2009 I photographed the same animal at Wigram.

It is to become part of the New Zealand Flying Schools fleet following NZ certification at Avtek Timaru. It will also get a full repaint in the NZFS colour scheme and be upgraded to full IFR standard.

It has new engines which off course are counter rotating and non turbo - ideal for twin engine training.

An interior item this time.
On what aircraft would you find this box of tricks.
& In case of a flood of correct answers - What specific model - then maybe what registration ?

We are looking at the strengthening modification applied to the undercarriage on some Murphy Rebels.

Two that I know about are the above ZK-JHY which was modified after a landing incident in (I think) November 1989 and ZK-VAL2 was upgraded before it gained NZ certification last May.

NO WINNER !

Wheeling along in butter-smooth air with Bill Canino in a Sting Sport S3, the gorgeous sunset world outside spins around us like a giant golden ball. Up into lazy wingovers, letting go of the stick, sliding down the long slide as the airplane builds up speed, eases itself out of the roll, smooth and quiet as a dream, and we feel that timeless joy that comes with true freedom. Then smooth easy back pressure, easing the stick over into another wingover the other way, and up and up we swing. The TruTrak EFIS shows our speed dropping like leaves on a windy day...90...80...70...60. We let the airplane have it's moment and down the nose slides again and we start all over, the golden/orange/gray blue sky and deep shadowed earth below swinging around the big clear bubble of our canopy like your best girl in a grand waltz.
---At end of the day, this is one of the reasons, maybe the best reason, why we fly light sport aircraft: for the pure joyful freedom of a dance through the sky.

Our Publisher Mike McMann walked the showgrounds with me today and was taken with the diversity and growing maturity of the industry. He also liked this lovely amphib LSA, the SeaRey. We'll catch up with it at Sun 'n fun.
---Mike's vision, from years back, (shameless plug here) of LSA as a driving force for all of general aviation is the main reason you're seeing this blog and monthly in-depth coverage of sport aviation in Plane & Pilot. He's committed! Thanks to Mike and our Publisher-in-Chief Steve Werner for seeing the potential from the beginning.
---Steve, a wizard at spotting developing cultural trends (and creator of successful magazines like Outdoor Photographer and Digital Photo Pro), published the successful Ultralight Aircraft that I edited in the early 1980s.)

Great to see general aviation giant Cessna supporting the show and LSA again this year with its Skycatcher. Look for more coverage in P&P and here as the lovely Cessna 162, it's official name, moves toward final ASTM approval and a market date later this year.

---Randy Schlitter, the creative dynamo behind (and in front and all around!) RANS Aircraft, who brought his newly certified Coyote S-6 to Sebring, (that's him in the Rans S-19 at right) put his own spin on why Sebring, which had it's best day ever Friday (turnout was again strong today), is the best show for him. "I spend one tenth of what it costs me to be at Oshkosh and Sun 'n Fun, yet I do the same amount of business at Sebring as at the bigger shows."

Barry Pruitt invites me in for our evaluation flight in the Evektor SportStar SL. What a wonderful, sweet-flying airplane...look for my report in an upcoming issue of dead tree P&P.
---Demo flights are a part of the warp and woof of air show convention, and LSA companies tirelessly give demos all day long, as their pilots transition from smiling, perky champions of their company's products to smiling, exhausted champions of their company's products. They are just a few of the unsung heroes of these shows and deserve all the appreciation we can give them. Thanks Barry and everybody for all you do to grow our wonderful sport!
---As our colleague and friend Dan Johnson reports on his own Splog (Sport Pilot Log), 14 aircraft have been sold so far in the first three days of the show. That's hard sales, not "I'm leaning toward buying".
---Adam Sandler, in a recent movie (You Don't Mess With The Zohan), as he waggled his naked foot in the face of an antagonist inches away, taunted him with "Smell it...smell it...smell it...now take it!", then WHAP! across the guy's face with his foot, all the while impossibly grabbing him by the collar. That's what Sebring is doing to the economy by giving a much-needed boost to start the sport flying year off right.
---Or as Franklin Roosevelt said, "The only thing we have to fear..."

The problematic Croatia Airlines Dash8

On Friday, January 23 a Croatia Airlines Dash8-Q400, a new aircraft, experienced yet another technical problem on route from Zagreb to Pula. Although such problems occur on a daily basis across the aviation world this incident is particularly worrying as the same aircraft has experienced an emergency for a second time in as many months. Many now believe that critics were right when they disapproved of Croatia Airlines’ choice of aircraft, with this particular type being withdrawn from service by major European carriers due to its unreliable safety record. In September, 2008 the same aircraft experienced problems because the fuel on board overheated. The exact cause of the latest emergency is unknown and Croatia Airlines has decided to stay quiet on the issue and not comment. The Dash8 joined the fleet in May 2008.

Croatia Airlines has released a short statement that it is perfectly normal for new aircraft to have technical glitches in its first year of operation. This statement is supported by Dinko Vodanović, an air crash investigator. He states that new aircraft have problems in their first year because they need time to get adjusted to the new conditions. Vodanović uses the example of Jat’s ATR72s, which were purchased in the early 90s and experienced minor technical problems once they entered service. Today they are the most reliable aircraft in Jat’s fleet.

Scandinavian Airlines SAS had particular problems with the Dash8. In 2007 a total of 3 Dash8-400s had landing gear failures. Immediately after these incidents SAS grounded all their 33 Dash-8-Q400 airliners and, a few hours later, Bombardier recommended that all Dash-8-Q400s with more than 10.000 flights be grounded until further notice. Last year Croatia Airlines had a total of 4 major emergencies – 2 with the now retired ATR42s, one with an A319 and one with the above mentioned aircraft. The Q400 costs 22 million Euros.

The ratios for L285, H285, H287 are:

100:50 by volume
100:40 by weight

I am doing some little layup today, so I decided to write the mixing ratio to my blog. I always tend to forget it and have to search from the MGS documentation. Now it is here in my blog. This same ratio applies to my MGS L285/H287.

A most pleasant surprise at Masterton was the reversion of Tiger ZK-ANL to agricultural configuration. This machine was the last of a long line of working Tigers and was operated by Marshall and Neville out of Bridge Pa as a sprayer until 28 December 1980. The spray gear looks to be in much tidier than it ever did on the original aircraft, as I recall. It kept company at Masterton with Wanganui Aero Work Tiger ZK-AUZ (fitted with hopper box and spreader) and both machines did it for real. Outstanding!

Visited Queensland across the Christmas/New Year period, but unfortunately the aviation industry was "gone - no forwarding address"! Caloundra was the shining exception - where do you get invited onto the field to wander at your liesure nowadays? The Queensland Air Museum has been struggling along for many years now, and I noted it was under threat from airport development this time. They have some nice stuff under cover, but there are some sad cases as well. This unloved GAF N22 Nomad VH-BFH (c/n 35) gets a bit worse each time, but you will note on the top of the fin the faded emblem of Southern Air in Invercargill. This machine served as ZK-SAL from early 1981 until July 1983 when it reurned across the Tasman. They also have Metro VH-BPV which did time here with Air Albatross (unfortunate name, that) as ZK-SWC in the mid 80's.

Across on the airfield, amongst the vintage machines, was H369HS VH-VLM which left here in June last year as ZK-HLM. It was cancelled from the NZ register on 17 June, and registered to an address in Buderim (just down the road from Caloundra) on 7 July.

The Masterton airshow last weekend produced some interesting visitors that I don't think get around much. Amongst them was Maule MX-7-180A ZK-MUL from Mount Manganui. It was first registered here 17 Jan 07.

Also positioned nicely was C180 ZK-CBH from Palmerston North. The 1956 vintage machine was imported from the US and first registered here 14 Mar 06.