Bu 131 Jungmann Spins Report

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CLASSIFIEDINTERNATIONAL TEST PILOT SCHOOL

SPINS PERFORMANCE REPORTON BCKER B 131 JUNGMANN BY MAJ ROSLIMIZAL BIN KAMAROZAMAN RMAF ITPS STUDENT

PREPARED FOR

CIVIL AVIATION AUTHORITY OF BORA-BORA

REPORT NO FTD090909

REVIEWED BY MR GIORGIO CLEMENTI (ITPS PRESIDENT) DATED 27 SEPTEMBER 2009

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SECTION 1. INTRODUCTION 1.1 BACKGROUND

The International Test Pilot School (ITPS) has been contracted to evaluate the spinning characteristics of the Bcker B-131 Jungmann aircraft. The request was originated by the Civil Aviation Authority of Bora-Bora which received an application from their local company to manufacture the subject aircraft. 1.2 PURPOSE OF THE TEST

The purpose of the test was to evaluate the spinning characteristics of the Bcker B-131 Jungmann aircraft as an aerobatic aircraft against FAR Part 23 requirements for certification purposes. 1.3 MISSION DESCRIPTION

A local company of Bora-Bora was intended to manufacture an exact replica of Bcker B-131 Jungmann as an aerobatic aircraft. 1.4 SCOPE AND CONDITIONS RELEVANT TO THE TEST

1.4.1 TEST AIRCRAFT The test aircraft was the Bcker B-131 Jungmann called C-FLAE owned by Mr Larry Ernewein. It was a two seat, bi-plane, wooden aircraft that built by the owner himself. The aircraft has a Tigre IVB, 4 in-line inverted cylinder piston engine with maximum of 150 hp. The empty weight was 1,050 lbs and maximum take-off weight was 1,650 lbs. The load factor of the aircraft was limited to +6g and -3g, while never exceed speed, VNE was 178 KIAS. The weight and centre of gravity (CofG) of the aircraft during the test was presented in Table I below and the weight and balance together with CoG position sheet was presented in Annex A.

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Flight First Second

Test Weight (lbs) 1,557 1,568

Test CofG (In aft of datum) 22.18 22.23

Table I. Aircraft Test Weight and Centre of Gravity 1.4.2 TEST VENUE The test flights were took-off from the London International Airport, Ontario, Canada. The test was carried out at 5,000 of QNE, west of London. 1.4.3 TEST TEAM COMPOSITION The ITPS Test Team consists of the following members: a. b. c. d. Major Roslimizal bin Kamarozaman Team Leader. Major Bruno Beeckmans Project Test Pilot. Major Samsuri bin Abu Bakar Engineer. Andrei Moise Engineer.

1.4.4 TEST SCHEDULE AND TEST CONDITION In total, 6 sorties of flight test which accumulated 6.0 flight hours have been performed. The first 3 sorties were carried out as demonstration flight for the test team members. This allows the test team members to have an experience as well as better perspective of the spinning characteristics of the aircraft before 3 sorties of data flight. However, since the PFDR was found inoperative during the first data flight, only 2 data flights were investigated and analyzed. The overview of the flight programs that have been conducted was presented in Annex B.

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1.4.5 TEST TECHNIQUE 1.4.5.1 ERECT SPINS

The aircraft was flown at stabilized altitude of 5,000 feet. The airspeed then was reduced gradually until aircraft experience normal stall condition. Rudder input was applied to the desired spin direction. Simultaneously, the control stick was pulled to fully aft position. As a result, the aircrafts wing at desired spin direction fell and the aircraft officially entered the incipient spin phase. Approximately after 1 turn, the aircraft finally stabilized in fully develop spin phase. At selected number of turns, opposite rudder input was applied and followed by neutralization of the control stick. This action was called as a standard spin recovery technique. Approximately after 0.5 to 1 turn of recovery phase, the aircraft was observed safely recovered. However, for certification purposes, multiple recovery techniques were evaluated as presented in Table II below: Test Points 1 Spin Entry Technique Spin Recovery Technique

Left rudder input, control stick Standard spin recovery technique, fully aft 4 turns - right rudder - neutralized control stick Right rudder input, control stick Standard spin recovery technique, fully aft 4 turns - left rudder - neutralized control stick Left rudder input, control stick 2 turns - aileron against turn direction fully aft 4 turns - aileron neutral 5 turns - recovery Left rudder input, control stick 2 turns - aileron with turn direction fully aft 4 turns - aileron neutral 5 turns - recovery Left rudder input, control stick 3 turns - elevator neutral fully aft +1sec - rudder against - recovery Left rudder input, control stick 3 turns - controls release fully aft 4 turns - recovery Table II. Type of spinning entry and recovery carried out 3 CLASSIFIED

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The above test points were then reflected in the Test Card as attached in Annex C. 1.4.5.2 INVERTED SPINS

The aircraft was flown at stabilized altitude of 5,000 feet. The aircraft was then positioned in inverted flight while gradually reducing the airspeed. Right before stall, left rudder input was applied and at the same time the control stick was push forward. The aircraft was then turned to the right in inverted condition. After 3 turns in fully develop phase, recovery phase was started by applying right rudder input and the control stick was released in neutral position. The inverted spins test point was also reflected in the Test Card attached in Annex C as Test Point 7. 1.4.6 TEST INSTRUMENTATIONS In order to collect the spins data, KUTTA Personal Flight Data Recorder (PFDR) has been utilized. 1.4.7 REFERENCES The following documents have been referred during the conduct of the spinning assessment: a. b. FAR Part 23 ITPS Stability and Control Manual.

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SECTION 2. RESULTS The results of the spinning flight test were presented in tabulated format in Annex D. In addition, the spin rate, roll rate, yaw rate, pitch rate and acceleration during the spin of first and second flight were presented in graphical format Annex E. The spin rate was obtained through application of this equation: Spin rate, = {(Roll rate, p)2 + (Pitch rate, q)2 + (Yaw rate, r)2} Overall, the spinning characteristics from both flights have shown a similar pattern in spin rate, roll rate, yaw rate, pitch rate and acceleration during the spinning as shown in Figure E1, E2, E3, E4 and E5 respectively. The data gathered proved that this aircraft portrayed predictable spin characteristics in every spin. 2.1 TEST POINT 1 NORMAL SPIN TO THE LEFT

Test Point 1 was a standard spin exercise to the left with normal spin entry and recovery. The aircraft was stabilized at predetermined altitude of 5,000 feet. The airspeed was gradually bled until the aircraft reach the buffet condition. Prior to stall, the pilot applied full left rudder and pulled the stick aft simultaneously. The aircraft smoothly entered the incipient phase within 1 turn without any oscillation. The fully developed spin phase was observed stable with average spin rate recorded was 190 deg/sec for the first flight and 210 deg/sec for the second flight. The maximum load factor for both flights was +1.58g and maximum airspeed during the spin was between 52 to 55 KIAS which met the FAR Sec. 23.221, Paragraph C (2) requirement. The spin rate was stable and there was no extreme oscillatory motion during the fully developed spin phase. These criteria were met the FAR Sec. 23.221, Paragraph C (4) requirement. The normal recovery process was initiated right after 4 fully developed spin by applying right rudder and followed by centralization of the control stick. The aircraft was managed to recover within turn in 2 seconds after initiation of the recovery actions with total height lost of 1,200 feet. Throughout any of the spin phase, it was observed that there was no tendency to enter the unrecoverable spin which met the FAR Sec. 23.221, Paragraph C (4) requirement. Therefore it was concluded an average aerobatic pilot will not encounter any difficulty to exercise the spin and able to exit the spin with the normal recovery procedures.

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2.2

TEST POINT 2 NORMAL SPIN TO THE RIGHT

Test Point 2 was a standard spin exercise to the right with normal spin entry and recovery. Average spin rate recorded was 175 deg/sec for the first flight and 220 deg/sec for the second flight. The aircraft was managed to recover within 0.8 turn in 2 seconds after initiation of the recovery actions. The average airspeed during the spinning was between 50 to 70 KIAS while the highest acceleration during the spinning was +1.86g. 2.3 TEST POINT 3 AILERON INPUT AGAINST SPIN DIRECTION

Test Point 3 was carried out with normal spin entry. Aileron input against spin direction was applied to simulate misapplication recovery method by any average pilot. Practically, it was observed that once input (aileron against spin direction) has been made, the spin rate was increased. However, the data from the PFDR revealed that there was no significant increase of the spin rate as shown in Figure E1. Instead, the yaw rate was drastically increased approximately 45% as shown in Figure E3. Meanwhile, the average roll rate was found dropped to 0 as presented in Figure E2. The phenomena of increasing in yaw rate and decreasing in roll rate has maintained the average spin rate to the normal rate. Even though with misapplication of aileron control, the aircraft was found still controllable and recovery is easy to obtain with normal recovery method. Recovery was made within 1 turn in 2 s