Pipistrel is the BIG WINNER of NASA General Aviation Technology Challenge 2008

The full story, results, media coverage and more!

We are proud to announce that we are the winners of NASA-funded General Aviation Technology Challenge for the second consecutive year!

-challenge summary and rules
-behind the scenes story
-media coverage



The event was hosted by the CAFE foundation. (Comparative Aircraft Flight Efficiency.)
This year the rules of the competition were especially strict. You can read them HERE.

The GAT Challenge comprises a number of individual events which aim to accurately determine the efficiency of entrant aircraft.


Five teams were competing this year:

“Team Pipistrel” flying a Pipistrel Virus 912, team leader Frank Vance Turner
“Team Aerochia” flying a modified Diamond DA20-A1, team leader Geoff Stevenson *
“Team Wilkinson Aero Sport” flying a Dynamic WT9, team leader Neil Wilkinson *
“Team Lambada” flying a UFM-13 Lambada, team leader John A. Dunham
“Team Flight Refine”, flying a Flight Design CT, team leader John Robert “Bob” Basham

 * Teams did not finish the competition due to technical problems.

  2008 PAV Challenge Rules Summary

(Or click HERE for the official page)


Read the official NASA report:



Behind the scenes story

Although the rules have changed (they were much more strict this year) our team managed to pull it off! The aircraft we used was a specially made Virus SW (a little over 10-meter wingspan), the same airframe that we used last year but heavily adapted to this year's competition rules. The preparations for the Challenge actually started quite a bit before the actual event at Charles Schulz Airport at Santa Rosa, which took place between 2-9 August, 2008.


Back in April, 2008, at the factory team Pipistrel experimented with various airframes, engines and propellers. The focus of the challenge were extremely low noise levels in the cockpit, extremely low community noise levels, good overall cross-country cruise speeds and fuel economy. You do not have to be a rocket scientist to see that these four things do not go well together. Be super-fast and you will be burning super-a-lot of fuel. Be quiet with a really tiny engine and you will not be moving fast enough cross country. Compromises, compromises...

The engine and propeller combination was chosen and noise reducing components tested to limit. The package of items to be sent to the USA was prepared and shipped overseas to Vance Turner, who is one of our dealers in the USA and was the leader of Team Pipistrel at the NASA GAT Challenge 2008. 

Virus SW in action

A week later, that is in early July, 2008, three of Pipistrels engineers went to the USA to prepare the Virus SW and update it to 2008 competition ready status. Boris Velikonja, head of Sinus/Virus production, Matej Fucka, our engine mechanic and Elvis Trebizan, our master electrical engineer flew to Rescue, CA, and worked hard for 10 days straight. The result was amazing! This years Virus is MUCH quieter and takes-offs and climbs MUCH better.

End of July, 2008, the Australian part of the team Pipistrel joined Vance Turner and his helping hand Fritz Henshaw in the USA. Michael Coates, our Australian dealer and the Pilot for the Challenge and his collegue Phil Allen, substitute pilot and assistante flew in. They ferried the Virus SW to Santa Rosa, CA, where the competition was to be held. Preparations for the event were in full swing!

Pipistrel Australia's Phil Allen reports:
"With flight tests completed and confidences restored, we undertook the quick flight across the amazing terrain of California to arrive at Sonoma County Airport housing the CAFÉ Foundation hangar on the western side of the field. Being the first to arrive, we were greeted by several of the volunteers of the CAFÉ Foundation who were preparing for the next week’s challenge. Vance arrived a few hours later in his modest RV, headquarters for Team Pipistrel.
Much of the preparations had been completed but there was still a lot more work to come with final tweaking of the instrumentation still underway. In order to get a head start on the proceedings of the next few days, and to prove the instrumentation, the CAFÉ Foundation team began immediate preparations of our aircraft for the challenge."

Pipistrel engineers modified the Virus SW in the USA, seen here before test flight

For the race, Tadej Hozic (Pipistrel's product manager) and Tine Tomazic (R&D and Test Pilot) joined the team to help out. The NASA GAT Challenge 2008 was hosted by CAFE Foundation, a World-renowned and recognised group of people specialising in impartial aircraft evaluation. The CAFÉ Foundation is supported in its efforts by skilled volunteers from Santa Rosa’s Experimental Aircraft Association (EAA) Chapter 124. These dedicated individuals are on hand whenever required to assist with all activities related to the event including general handling of the aircraft, monitoring refueling and other operations, providing escorts for the teams and visitors and any other administrative tasks as required.

The Challenge itself was organised in groups of evaluations. But first, let's meet the competition. Team Pipistrel flew the Virus SW under competition number 1. The Flight Design CTSW flew under compeition number 2 and the Urbain Air Lambada under number 3. Number 4 and 5, a bio-diesel DA-20 and WT-9 Dynamic did not compete due to technical problems with their aircraft.


During the first couple of days of the challenge, all aircraft were fitted with the Uber-Barograph, CAFE's in-house super-precise almost space-age pitotstatic measuring equipment in order to calibrate all the instruments.

CAFE Team working hard with their instruments

As Phil Allen puts it: "The highly sensitive and accurate equipment is connected in parallel with the aircraft systems through the pitot and static lines. To ensure that no tampering occurs, a camera is also placed in the aircraft which records the pilot’s actions throughout the flight. Additional instrumentation measures noise levels within the cockpit. All measurements are relayed directly to a ground receiving station through radio telemetry links. When the aircraft travels out of range of the receiving station, the data is automatically buffered and retransmitted once the aircraft returns and as a final failsafe the equipment also records all of the information which can be downloaded later into the CAFÉ’s computer. To calibrate the equipment and adjust for pitot and static line anomalies, an external barograph is fitted to the wings and a series of calibration flights are undertaken. CAFÉ Foundation staff review the video footage from the onboard cameras after every flight.

UberBarograph fitted to Virus SW

A number of test flights were conducted for the benefit of the CAFÉ Foundation to enable them to correctly calibrate and test their equipment in-flight. This proved invaluable as a number of issues were discovered and rectified early prior to the fitment of the equipment to the various other entrants, saving both time and effort for the CAFÉ Foundation volunteers and team entrants alike. NASA officials were on hand throughout the challenge to oversee all aspects of the data collection and to ensure that the NASA approved rules were adhered to. Every aspect of the challenge is scrutinized, from buying fuel at the local service station and refueling operations to making any modifications to engine and equipment fittings on the aircraft. Once the aircraft have been equipped, calibrated and weighed no further modifications are permitted and the aircraft are effectively impounded for the duration of the challenge. All team members must be escorted whenever they approach the aircraft to ensure that the equipment and aircraft were not tampered with."

Measurements under way

The competitors then flew with a number of test pilots and judges who's job it was to evaluate aircraft flight qualities and general passanger feelings in the air. 
The Cooper-Harper rating system is used to rate the aircraft.

CAFE test pilots before their flights

The second series of tests were the noise tests, coupled with take-off and climb performance. The aircraft were fitted with an in-cockpit microphone (mounted in a special anti-vibration housing) and there was a series of microphones on the ground for community noise measurements. The aircraft then performed a series of take-offs and climb-outs where all parameters were measured. It was interesting to see how steeply the Virus climbed! Results prove that we did it almost two times better than the competition! Everybody was impressed, even the CAFE team who saw the same airframe last year - they kept asking us what we did to improve the performance so dramatically...
Of course the big secret is in the black tape we used - now we can reveal that it resembles shark skin in the aerodynamically most sensitive areas, providing for a laminar airflow a looooong way across the airframe. You can see this in the pictures.


The last series of tests were combined in the cream-of-the-crop event, the CAFE 400 race. This is a race in 400 statute mile length, coupled with climbs and descents along the course. It is really well thought out and takes a lot of precision flying and careful strategic preparation. The base formula that CAFE uses to calculate the results of the "400 Race" is:
V x MPG x W
V = aircraft’s average velocity over the course
MPG = average miles per gallon of fuel used
W = aircraft’s payload in pounds

The morning of the 400 Race: course, breifing, preparations

Before the race Michael and Phil programmed the GPS and all onboard avionics, while Tine worked out the route flying strategy taking into account the winds, turbulence, specific consumptions at altitude etc. The rest of the team polished the Virus SW and made sure that all systems were in perfect shape. Then, they departed. Virus SW as 1, CTSW as 2 and Lambada as 3. They took-off in one minute intervals.

The race is on!
After less than 3 hours there was an aircraft on the horizon. It was Michael Coates with our Virus SW! Crossing the finish line with the checkered flag the team was anxious to see when the next aircraft would show up. Remember that they took of in 1 minute intervals... The Lambada showed up as the second, 10 minutes after our Virus and the CT came last a full 21 minutes after the Virus. Interesting enough, our Virus also had the BEST FUEL ECONOMY and was made it around the track THE FASTEST. This is unparalleled performance! Much better than Lambada, much better than the CT. The results speak for themselves!

Later that evening there was the awards ceremony. Pipistrel with the Virus SW was again the BIG WINNER of the Challenge.

  We came aroud the course first and were immediately surrounded with TV crews



Place Points Producer Model Category won Prize won
1 317,3 Pipistrel Virus 912 SW The Aviation Safety Prize (Handling, eCFI) $ 50,000

The CAFE 400 Prize (speed and fuel consumption) $ 2,000

Take off distance over 50 foot obstacle $ 3,750

Angle of climb $ 3,750

Cabin Noise (prize shared with Lambada) $ 1,875

The Green prize (fuel consumption) title only

Top speed title only

The best climb rate task title only
2 249,3 Urban Air LAMBADA UFM-13 The Community Noise Prize $ 20.000

The Quietest LSA $ 10.000

Cabin Noise (prize shared with Pipistrel) $ 1.875
3 225,6 Flight Design CT 180 Best gliding ratio at 100 $ 3.750

Lowest speed $ 3.750
4 quit Diamond KATANA DA20-A1 none none
5 quit Aerospool DYMNAMIC WT9 none none

Team Pipistrel posing proud with the awards

The following table details some of the performance characteristics determined by the CAFÉ Foundation for each entrant:


Pipistrel N2471P

Flight Design CT N135CT

Lambada N109UA

Takeoff Distance

924 feet

1168.1 feet

1011 feet

Top Speed

145 mph

117.7 mph

130 mph

Slowest level flight speed

51 mph

44.5 mph

47 mph

Cabin Noise

91.5 dBA

94.5 dBA

91.5 dBA

Community Noise

67.4 dBA

68.1 dBA

62.9 dBA

Miles Per Gallon

28.8 MPG

25.2 MPG

26.5 MPG

Rate of Clilmb

1039 fpm

458.2 fpm

769.5 fpm

Angle of Climb

8.9 deg

3.9 deg

6.7 deg

Empty Weight

717.3 lb

751 lb

732 lb

Link to official CAFE results 
Link to official NASA news release
Final Report on the CAFE - NASA 2008 GAT Challenge (by Phil Allen) 


The Prime Minister of Slovenia, Mr Janez Janša, congratulated the Pipistrel Team for the success on the NASA GAT Challenge in the USA.

(Slovenian original)             (English translation)



Media coverage of the event:

In English Language:
Cnet News
A detailed and amusing report of everything that happened at this year's NASA CAFE Challenge in the USA, written by Mr Phil Allen.
Click HERE to download the PDF!
Australian Flying, Nov-Dec 2008



In Slovenian language:
Večer.si (online)

Primorske novice
Primorske novice.si (online)

Delo.si (online)




Slovenske Novice

7 Dni (title page)  (index)  (pg.1)  (pg.2)  (pg.3)
7 dni online: The title page   The article

Radio Energy Krško

Ajdovski Pipistrel znova zmagal na natečaju NASE (stran 1) (stran2)

E revija

RTV SLO (online)

Screenshots from the evening news of Slovenian TV stations:
TV Slovenija 1:



TV Primorka:


Radio Slovenia: voting for the "Name of the Week"





Ivo Boscarol, Pipistrel GM:

Let me use this opportunity to thank the entire Pipistrel team and everyone who contributed to this great success of Pipistrel, especially (in alphabetical order):

Leon Brecelj,
Michael Coates,
Matej Fučka,
Tadej Hožič,
Elvis Terbižan,
Tine Tomažič
Vance Turner,
Boris Velikonja.

I would also like to thank the NASA CAFE foundation and all the organizers who gave us the opportunity to participate in this exciting competition, for fair and unbiased assessment of the teams and for professional execution of the competition.

Thank you!



Tine Tomazic, Pipistrel R&D:

At this time I would like to thank the complete team which made all this possible, all our management, our factory people, Vance Turner, Fritz Henshaw, Michael Coates, Phil Allen, the whole of the CAFE foundation team and volunteers, Brien Seeley for inviting us to attend the race, C.J. Stephens and Will Whiteside for sharing invaluable experience about text flying and Mark Moore for his fantastic ideas. Thank you all very much and we promise we will be back!

Phil Allen, Pipistrel Australia:

Team Pipistrel is lucky to have direct support from the Pipistrel factory who have committed to using the knowledge gained from these events to further improve their already remarkable products.  Future versions of the Virus SW, due for release in early 2009, will incorporate many of the modifications and information learnt from these challenges to provide more efficient, quieter aircraft into the market.

Even with the intense competition, the NASA CAFÉ Foundation GAT Challenge fosters camaraderie, friendship and teamwork from all involved.  We were certainly privileged to work and compete with such a great team of professionals.

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