UL 2 – Part II.

CONTENT

1. GENERALLY
2. REQUIREMENTS FOR LIMIT VALUES
3. STATIC LONGITUDINAL STABILITY ULLt
4. FORTIFICATIONS, CONSTRUCTION PRINCIPLES
5. FLIGHT CHARACTERISTICS
6. POWER UNIT
7. MARKING AND LABELS
8. FLIGHT INSTRUMENTS
9. SUBSTANCES REQUIRED BY MANUFACTURER
APPENDIX 1
10. STRENGTH CHECK OF THE ASSEMBLY BEAM
11. CHECKING IMPORTANT ULLT NODES

 

1. In general

1.1 Validity and Scope

These building standards establish the minimum airworthiness requirements for UL aircraft listed in point 2. It ensures that the use of UL aircraft is problem-free, that the safety of air traffic is not compromised as well as general safety and order.

These standards apply together with the general principles stated in the UL - 2 regulation and LA - 2 LAA CR Procedures for aircraft airworthiness verification.

1.2 Use

These airworthiness requirements may be used for UL airplanes:

a) motorized hang gliders controlled by changing the position of the center of gravity / ULLt /
b) motorized paragliders with landing gear / MPK /
c) motorized paragliders without landing gear / PPG /

 

2. Requirements for limit values

2.1 General

The limit values ​​listed below are generally valid norms that can only be adjusted in justified exceptional cases due to the specific characteristics of the machine. All values ​​obtained during flight tests must be converted to international standard atmospheric conditions.

2.2 Mass limitation

2.2.1 Maximum take-off weight

2.2.2 Minimum load for ULLt

Crew load weight restrictions must be

for single at least 90kg,
for a double at least 180 kg.

2.2.3 Minimum load for powered paragliders

The weight limit for crew load is set by the applicant within the strength limits.

2.3 Minimum Speed

Drag speed V_SO must not exceed 65 km/h CAS. Velocity V_SO is the lowest steady speed at which the UL-aircraft is still controllable, with the engine operating in idle mode or switched off.

2.4 Minimum power of the drive unit

The propulsion unit must enable the flying device to achieve the following minimum outputs, with the engine operating at sustained cruise power and maximum take-off weight.

2.4.1 Minimum rate of climb

1,5 m/s for ULLt
1,0 m/s for powered paragliders.

2.4.2 Take-off length

The power unit must allow the maximum take-off weight to reach a height of 300 m after 15 m from the take-off point.

 

3. Static longitudinal stability ULLt

Static longitudinal stability is demonstrated by flight tests.

3.1 Basic data

Airplanes with a Type Certificate must always be tested with a testing device to verify the values ​​of longitudinal stability. These tests are performed at a minimum speed of 100 km/h. In doing so, variants of angle of attack and speed are tested and the following values ​​are determined:

a) buoyancy
b) resistance
c) rotational moment about the transverse axis
d) speed
e) angle of attack relative to the wing keel tube

3.2 Numerical load

On the basis of the data obtained according to 3.1, it is necessary to make a license plate. It is necessary to demonstrate whether the wing exhibits sufficient static longitudinal stability.

3.3 Test limits

The tests according to 3.1 and the calculation according to 3.2 must be carried out for all limit values, if, based on previous experience, the limit value is not covered by other tests and the simultaneous occurrence of different limit values ​​is unlikely.

If the wing setting can be changed in flight in such a way that it affects the aerodynamic characteristics, then tests must be carried out both for all maximum permissible values ​​and for all possible adjustable intermediate positions.

 

4. Strength certificates, principles of construction

4.1 General

All elements of the structure must transfer operating load without permanent deformations.

The strength connections must last numerical load for at least 3 seconds without failure.

4.2 Strength certificate of load-bearing surfaces ULLt

The certificate of strength is carried out by tests. Air forces are simulated with either a test car or static tests.

Inertial forces are introduced in the appropriate direction corresponding to the ULLt flight position. In special cases, the LAA-

The test load serves as a basis for calculating operational and numerical loads. The test load is calculated from the maximum allowable take-off weight minus the weight of the wing.

• m_try = m_Max - M_kr
• service load positive: 4 times the test load
• service load negative: 2 times the test load
• numerical load positive: 6 times the test load
• negative numerical load: 3 times the test load

 For amateur structures, it is possible to check the strength of individual parts of the structure according to the tables and calculation procedures listed in the appendix.

4.3 Chassis strength certificate

Proof of strength is carried out by tests. Air and inertial forces are simulated by static tests. The points where the load is introduced must be tested in the flight position.

4.3.1. Strength certificate of suspension points, principles of construction

ULLt suspension points must be tested for the numerical load specified in point 4.2.

4.3.2. Suspension of the landing gear to the keel beam

a) It must be carried out safely and secured in parallel. The parallel protection must be connected to a solidly compliant chassis node that does not disassemble or move. Securing with a steel cable min. 2 x diam. 3,15 or using a strap with min. basic strength

F min 50 x ms
F min / N /, ms / kg / ... definitions in the appendix

b) Recommended screw diameters are:

– for max. landing gear take-off weight up to 190 kg M 10 G8, for higher weights min. M 10 K10

4.3.3 Fastening the rescue system

When installing the rescue system, the parachute strap must meet the conditions specified in point 4.3.1. The rescue system must be connected up to the basic construction node of the chassis, to which the seat and fastening belts are connected. The parachute must not be anchored only by the upper hinge. The recommended end of the strap is an eye and ambulatory knot.

4.3.4 Strength certificate of the main chassis

The main landing gear must withstand:

a) Vertical landing impact at a fall speed of 2,0 m/s without damage or withstand a static load of 4g without damage.
b) Lateral loading of the chassis:

To determine the landing gear side load, it is assumed that it is flying in a horizontal position, with the main landing gear wheels touching the ground and

1) a force equal to 1,34 times the maximum weight of the aircraft (G) acts at the center of gravity of the aircraft, equally distributed to the main wheels
2) operating lateral inertial forces of 0,83 G at the center of gravity of the aircraft are distributed between the wheels of the main landing gear in such a way that:

i) 0,5 G acts on one side towards the torso
ii) 0,33 G acts on the other side of the fuselage

c) Braking

It must be demonstrated that the braked wheels of the landing gear will meet the load when

1) vertical operating load per wheel is 0,67 G
2) the horizontal load at the point of contact of the wheel with the ground is 0,54 G towards the rear.

The nose landing gear must withstand:

a) For the resulting rearward load, the components of the force acting in the axis must have the following magnitude:

1) the vertical component corresponds to 1,5 times the value of the static load of the wheel a
2) the resistance component corresponds to 0,5 times the vertical load,
3) the lateral component of the load corresponds to 0,5 times the vertical load.

4.3.5 Emergency landing

UL-aircraft strength connections must be designed so that the pilot escapes with a high probability of serious injury in an emergency landing if

a) seat belts are used correctly and
b) if the following numerical acceleration acts on the pilot

– up 3g
– forward 9g
– to the side 1,5g
– down 6g

4.3.6 Seat, backrest and seat belts

It must be safely ensured that the seat, backrest and harnesses can withstand the load according to 4.3.5 Emergency landing.

Pilots must be fixed with seat belts (minimum two-point seat belts) so that they are still in the same position during all accelerations and flight positions that occur during operation, as well as during a hard impact.

4.3.7 Mounting the motor

It must be safely ensured that the motor mount will last according to 4.3.5.

4.3.8 Attachment of payload

If the aircraft is intended to hold a payload, it must be designed to withstand the greatest multiples that can arise in flight and ground load cases. The use of an emergency landing multiple of 9g for the load holder and fastening device is required when there is an immediate danger to the crew in the event of an emergency landing.

4.4 Paraglider certificate of strength

The strength certificate of a paraglider must be carried out on the basis of the documents required by the LAA.

4.5 Certificate of strength of the power unit of a motorized paraglider (MPK chassis, PPG drive unit)

4.5.1 General

For machines with a chassis, the test regulations according to points 4.2 and 4.3 apply.

4.5.2 Fasteners

For connecting elements between the suspension system and the parachute, or between the landing gear and the parachute, a strength test must be carried out according to point 4.3.1.

4.5.3 Propeller cover

Parachute and pilot lines must be protected by a suitable cover from contact with the propeller. It must be safely demonstrated that no loose parts of the suspension system or clothing can come into contact with the propeller. The strength of the cover must ensure that the propeller does not come into contact with the cover when tipped over.

4.5.4 Engine bed and its fastening system

The engine bed and its fastening system must meet the requirements of point 4.3.5.

4.6 Strength certificate of motorized paragliders without landing gear

Airplanes where the pilot lands on his own feet may not have any special equipment to absorb the landing shock.

4.7 Proof of service life of the drive unit

All parts of the engine must be designed, arranged and built to ensure safe operation during the specified inspection and inspection intervals.

Detailed construction regulations for the drive system and for the engine are given in chapters E and H of the basic regulation UL - 2 part I.

4.8 Propellers

Design principles, strength requirements and approval principles are given in Chapter J of the UL - 2 regulation.

4.9 Tow hitch strength certificate

It is necessary to carry out a tensile test of the towing hitch with a tensile force of 1 N, on the towing hitch installed in the UL-aircraft.

Tensile tests are performed:

– in the direction of the propeller axis a
– up to 90° deviation from the axis direction
– The release force on the latch mechanism must be between 50 and 150 N during tensile tests.

 

5. Flight characteristics

5.1 General

5.1.1 Flight tests

Demonstration that the UL-aircraft complies with the requirements set out in this section is carried out by flight tests. The requirements of this section apply to UL-aircraft both with the engine running and with the engine off.

The test is conducted by an LAA test pilot.

The Type Certificate applicant must test the corresponding flight maneuvers independently and submit the results to the LAA. The results will be verified by 2 test pilots independent of the manufacturer.

5.1.2 Controls and Controls

Each control and all controls shall be so adapted and marked as to permit easy operation and to prevent confusion of an obvious function or unintended operation.

5.2 Take-off and landing

The UL-aircraft must be able to take off and land without placing extraordinary demands on the pilot or requiring his extraordinary skill.

During the operation of the landing aids, at all permissible speeds, these must not cause excessive changes in control forces or control deviations or affect the controllability of the UL-aircraft in such a way that it would require extraordinary skill of the pilot.

5.3 General reversing in flight

The UL-aircraft must fly and perform all normal flight maneuvers in all flight conditions and conditions over the full range of speeds without placing extraordinary demands on the pilot or requiring extraordinary pilot skill.

5.3.1 Balancing

It must be possible to balance the UL-aircraft within the range of permitted take-off weights at speeds between minimum descent and optimum speed.

5.3.2 Oscillation, vibration, collapsing

In its entirety, it must not

– no fixed part of the structure exhibit oscillations and
– no moving parts of the structure exhibit excessive vibration.
– There must be no shaking (vibration).
– Shaking (vibration) is allowed as a warning against dragging.

In the case of a UL-aircraft, undesirable deformation of the wing must not occur in the entire speed range due to influence

– aerodynamic action (aerodynamic collapse)
– ambiguous flight behavior (divergence) a
– changes in the orientation of the steering action.

5.4 Controllability ULLt

5.4.1 Height control

It must be possible to maintain a constant speed without extraordinary demands on the pilot's skill throughout the range of permissible speeds.

5.4.2 Change of turns

It must be possible to go from a 30° banked turn to a 30° banked turn within 5 seconds without extraordinary demands on the pilot's skill.

5.5 Stability of ULLt

It is necessary to demonstrate stability in flight around all pro axes

– the entire range of speeds
– all flight positions
– permissible take-off weights
– all possible engine modes
– all configurations

5.5.1 Flight behavior with free control

The UL-aircraft must remain 10 revs in straight flight at balanced speed.

5.5.2 Static longitudinal stability

In all flight modes, the dependence of the control force on the speed must be positive, so that the change in speed causes such a change in the force in the hands of the pilot that it is clearly registered by the pilot.

The speed must change in the correct sense and in a reasonable proportion for each constant deflection of the steering.

5.5.3 Static directional and lateral stability

When flying in a turn, the steering force in the longitudinal direction or in the lateral direction must not be so great that the steering becomes difficult.

5.5.4 Dynamic stability

All oscillations about the transverse axis that occur between the stall speed and V_NE they must be damped while the steering is relaxed or firmly held. All other oscillations that can be corrected without extraordinary demands on the pilot's skill must be damped throughout the speed range.

5.5.5 Corkscrew and flat corkscrew

There should be no tendency to go into a corkscrew or flat corkscrew.

5.6 Drag behavior for ULLt

After a slow stall, it must be possible to restore the normal flight attitude after lowering the nose without extraordinary demands on the pilot's skill, without achieving a bank of more than 30°.

After the interruption of the performed longitudinal tilt of 30° with respect to the horizon, the nose down must not be abrupt and bringing the UL-aircraft into normal flight condition must not require extraordinary skills of the pilot.

5.7 Flight characteristics of motorized paragliders

They are verified with the engine running and with the engine stopped.

5.7.1 Management

It must be possible to maintain a constant speed throughout the applicable speed range without extraordinary demands on the pilot's skill.

5.7.2 Turns

It must be possible to smoothly transition from a 20° banked turn to a turn in the opposite direction of the turn, without requiring extraordinary pilot skills, with the allowance setting constant.

5.7.3 Flight behavior with free control and constant clearance setting

A motorized paraglider must remain in straight flight for 20 seconds while maintaining a constant speed.

5.7.4 Interventions in proceedings

The rate of rotation and the amount of tilt must change with each intervention in the steering in the right sense and in a reasonable proportion.

5.7.5 Directional stability

After smooth release of control in turn mode with a 20° tilt, the motorized paraglider must return to the straight flight direction within 3 seconds.

5.7.6 Stability around the transverse axis

After retracting the steering wheel to the position corresponding to the maximum speed mode, the pilot forcefully releases the steering wheel. The PK must not preshoot by more than 90°, snapping is permissible if the flight path does not change by more than 90°. The glider immediately goes into controllable flight. This test can be performed with the engine at rest.

5.7.7 Behavior of the MPK in the area of ​​flight with a large angle of attack

Incipient flow separation must be clearly discernible.

5.7.8 Stability around the longitudinal axis

All oscillations around the longitudinal axis must have the character of damped oscillations.

5.7.9 Crashing of a motorized paraglider

When the canopy of a motorized paraglider is collapsed by frontal tilting in the range of 50% (+/-5%) of the bearing area, it must be ensured that it is possible to return to the normal flight mode after turning by a maximum of 180° or within 4 seconds. and only using standard management. This test can be performed with the engine at rest.

5.7.10 Asymmetric PK drag

After braking the PK to minimum speed, the pilot pulls back one side of the control so that the flow breaks off on that side. At the moment of the first manifestations of the reaction of the canopy, the pilot releases the controls. The PK must spontaneously return to controllable flight without changing flight direction by more than 90°. This test can be performed with the engine at rest.

5.7.11 Rotational moment of the drive unit

It must be safely guaranteed that even the maximum reaction moment of the drive unit can be eliminated by steering to the extent that the flight takes place in normal flight mode and a sufficient degree of controllability is ensured.

5.7.12 Parachute geometry

The combined suspension of the pilot and power unit, or the suspension of the landing gear must not affect the geometry of the MPK canopy.

 

6. Power unit

The basic building and technical regulations are given in chapter E and chapter H of the UL regulation – 2 part 1.

6.1 Enduring Performance

Even at minimum power, the engine must show stable operation without speed fluctuations. The engine must deliver full power for 5 min., there must be no drop in power, overheating or other symptoms of overload or wear.

6.2 Noise

The latest edition of the protective noise regulations for UL-aircraft always applies.

6.3 Fuel tank

The fuel tank must be removable. The following requirements must be met:

• It must be a tank that is suitable for the fuel and that must withstand the expected liquid load.
• A suitable fuel level indicator must safely ensure that the pilot has an overview of the fuel level.
• The fuel tank must be conductively connected to the supporting structure against static electricity.
• The tank vent must be positioned to prevent liquid leakage.

6.4 Fuel lines

The fuel line must be made of material intended for this purpose and must not touch hot engine parts. There must be no friction points.

6.5 Propeller safe distance

For an uncovered propeller, the safe distance at maximum weight, in the most unfavorable plane of the center of gravity, must not exceed the following values:

a) Distance from the ground: at least 170 mm between the propeller and the ground.

At the same time, the landing gear must be statically compressed and the aircraft is in the take-off position. In addition, a safe distance must be maintained in the starting position if:

(1) the critical tire is completely depressurized and the relevant chassis strut is statically loaded or
(2) the critical chassis strut is at stop and the corresponding tire is statically loaded.

6.6 Safe distance of the propeller from other parts of the structure

Safety requirements for an uncovered propeller must be established for the worst case load.

The radial distance between the tip of the propeller blade and adjacent structural elements must be at least 50 mm. Above all, it is necessary to consider the flexible suspension of the engine unit. At least 13 mm longitudinal distance between the propeller head, propeller blades and other rotating parts of the power unit from adjacent parts of the structure.

A safe distance between other rotating parts of the propeller or propeller hub (including its housing) and other parts of the aircraft must be maintained under all operating conditions.

6.7 Anti-vibration protection (for push drive arrangement)

All engine components that are stressed by vibrations and whose structural solution allows failure (exhaust pipe, air cleaner, etc.) to be secured against possible contact with the propeller.

6.8 Option to switch off

The switch that interrupts the engine ignition, i.e. brings the drive unit to a standstill in the fastest way, must be easy to operate and prominently marked. Ignition switches must be arranged and designed to prevent their inadvertent use.

 

7. Markings and Labels

7.1 Registration plate

There must be a registration label on the fixed part of the structure, which must not be easily erased.

a) Name of the manufacturer (company)
b) Type name
c) Year of manufacture
d) Serial number (if manufactured by a company)
e) Registration mark
f) Empty weight
g) Maximum take-off weight

7.2 Labels with operating data and limitations

a) This aircraft (sport flying device) is not subject to approval by the Civil Aviation Authority of the Czech Republic and is operated at the user's own risk. Acrobatic turns, intentional corkscrews and falls are prohibited.
b) Empty weight

7.3 Designation of pyrotechnic ZS

a) Small symbol – place directly on the ZS, or in its immediate vicinity (for ZS built into the kite, place it on the outside of the fuselage in the area of ​​the shot).

Graphic form: a yellow isosceles triangle about 7 cm high with the inscription: "PYROTECHNIC DEVICE - BEWARE OF IMPROPER HANDLING - DANGER OF INJURY"

b) Large symbol – place on the upper and lower sides of the bearing surface in its rear part, near the longitudinal axis of the aircraft (on the cover next to the keel)

Graphic form: a yellow isosceles triangle about 13 cm high with the inscription: "THE PLANE HAS A PYROTECHNIC DEVICE - BEWARE OF IMPROPER HANDLING - RISK OF INJURY"

Note: For motorized paragliders (MPG) and other machines, where symbols cannot be placed on the SOP or on the bearing surface, the small triangle is placed as in the previous case, and the large triangles are placed on the free side surfaces of the landing gear. If this is not possible, large triangles are placed directly on the ZS instead of small symbols.

 

8. Flight instruments

8.1 ULLt

Required equipment: speedometer, altimeter, compass
Recommended equipment: variometer

8.2 MPK, PPG

Required equipment: altimeter, compass
Recommended equipment: variometer

8.3 Power unit instruments

a) Fuel indicators
b) If the engine manufacturer requires or is required to ensure the operation of the engine within its limitations, the equipment of thermometers, pressure gauges and tachometers is requested

All maximum and, if given, minimum values ​​for safe operation must be marked with a red radial line.

 

9. Documents required of the manufacturer

Application for type certificate.

Application for an individual airworthiness certificate type A or Z.

Scope according to LA regulation – 2.

9.1 Bearing surface (wing) ULLt

• three-view drawing with the following information:

a) span
b) surface projection
c) nose angle
d) slenderness
e) the size of the lower cover relative to the upper cover in percentage
f) the number of reinforcements in the sail
g) method of tying the sail (anti-fleet cords)
h) empty weight (without packaging)

• wing drawings:

a) developed wing shape
b) middle profile (side view)
c) data on wing stitching
d) wing material, weight, composition, fabric manufacturer, trade name

• assembly drawings of all structural and strength nodes
• piece with material specification
• data on operational limitations

a) maximum take-off weight
b) minimum take-off weight
c) falling speed V_SO
e) maximum unexceeded speed V_NE

9.2 Paraglider

• proof of LAA, SHV, DHV type certificate in non-engined version for design weight
• type sheet
• data on possible types of suspension systems
• technical data according to ZL 2 part 2 – paragliders

9.3 Chassis system / Drive

• three-view drawing with the following information:

a) external dimensions
b) gauge and wheelbase of the chassis
c) height to attach the support surface
d) volume of fuel tanks
e) empty weight without fuel

• assembly drawings of all structural and strength nodes
• bill of materials with material specification
• power unit used

9.4 Rescue equipment

• Type certificate LAA, DHV, SHV

9.5 Operations Manual

The operating manual must contain the following information:

• description of all structural groups of the UL-aircraft
• build and layout description
• instructions for use of rescue equipment
• overview of pre-flight operations
• operational limitations: weight limitations, speed range, permissible and impermissible flight maneuvers
• motor limit values
• limit values ​​for the position of the center of gravity
• special features: assembly, layout, transport, etc.
• details of the maintenance method, maintenance procedures and inspection intervals
• maintenance notebook for recording performed inspections and tests

 

Annex 1 to UL2 part II

Strength control of parts of bearing surfaces / wings / ULLt.

10 Inspection of the tubes of the bearing surface ULLt

10.1 Strength check of the leading beam

The ramp beam must withstand the bending moment M without permanent deformation_O=0,15G_s.lz follows after adjusting the condition for the length of the flying end l:

 

d₁ – outer diameter of the leading beam
d₂ – inner diameter of the leading beam

 G_s=m_s.g

m_s = m_p + m_pil + 0,5m_path

m_s – comparative weight
m_pil – weight of the pilot at least 90 kg for a single-seater, 180 kg for a two-seater
m_p – chassis weight with full fuel
m_path – the weight of the rescue system
l – the length of the flying end of the leading beam, i.e. the distance of the axis of the screw in connection with the crossbar from the edge of the sail. For wings finished with a laminate rod, 0,35 of the length of this rod is added.

 ς_odov = 250 MPa – for duralumin ČSN 4244203.61

g = 9,81 ms^-2

After adjustment, it is a condition for the length of the flying end for the duralumin tube

l ≤ 0,17 W_O/m_s

W_O [mm³], m [kg], l [mm]

 Maximum flying end lengths for some typical pipe sizes are in Table I.

10.2 Reinforcement of the leading beam

The reinforcement, which is formed by a cover or an insert at the point of connection with the crossbar, has a minimum length

l_p = 0,5l

The reinforced lead beam must meet condition W_OZ ≥ 1,5W_O

For the disguise is:

d_p – outer diameter of the cover

for the insert is:

d_v – inner diameter of the insert

10.3 The reinforcement at the bolt location must compensate for the weakening caused by the hole. Another disguise of length 8d₁ must meet the condition:

 d_Max is the largest diameter of ad_min the smallest diameter of the reinforced lead beam at the point of the bolt

10.4 Typical constructions of the leading beam:

fig. 1 – reinforcement by disguise

fig. 2 - reinforcement with an insert

fig. 3 – amplification by inserting two tubes

fig. 4 – It is recommended to gradually thin out the cross-sections of the covers or to cut them at an angle

10.5 Defectoscopy of cracks must be carried out very carefully in the vicinity of the connection of the leading beam and the transom ± 1 m

10.6 Strength check of the cross member

The crossbar must withstand buckling stress with a force of 4G_s. This results in the condition for the length of the crossbar l_P (duralumin tube):

D_p [mm] – outer diameter of the crossbar
d_p [mm] – internal diameter of the crossbar
m_s [kg] – target weight (as for the starting beam)
l_p [m] – buckling length of the cross member
Crosspiece lengths for some typical pipe sizes are in Table II.

10.7 Strength check of the trapeze arm

The arm of the bar must withstand a buckling stress of 2,76G_s. This results in the condition for the length of the crossbar l_h (duralumin tube):

m_s [kg] – target weight (as for the starting beam)
D_h [mm] – outer diameter of the trapeze arm tube
d_h [mm] – inner diameter of the trapeze arm tube
l_h [m] – buckling length of the trapeze arm

10.8 Keel tube

it must bear the bending moment as a leading beam, i.e. M_O = 0,15G_sl. At the point of connection with the crossbar and suspension of the chassis, there is a reinforcement with a cover or an insert. The minimum wall thickness of the insert or cover is 1,5 mm. Additional reinforcement at the opening is not necessary.

10.9 Recommended Connections

The following applies to the bar handle:
If it is bent on a speed bar, it is necessary to thread a cable with a diameter of 3,15 mm through the inside of the bar between the hardware screws.

 

11 Control of important nodes ULLt

11.1 Suspension of the landing gear to the keel beam

must be safely executed and secured in parallel. The parallel securing must be led to a strength-compliant undercarriage node that does not disassemble or move. Recommended screw diameters are:

per m_s up to 190 kg M10 G8, for higher weights min. M10 K10
securing the keels - the suspension is carried out using a cable - 2x diameter 3,15 mm or using a strap with a min. basic strength F_min ≥ 50m_s F_min [N], m_s [Kg]

11.2 Installation of a safety rescue system

When installing a safety rescue system, the parachute strap must meet the conditions specified in point 2.1. The rescue system must be connected up to the basic construction node of the chassis, to which the seat and fastening belts are connected. Anchoring the parachute only by the upper hinge is inadmissible

11.3 Table I.

11.4 The greatest length of the flying end of the leading beam

11.5 Table II.

11.6 Table III.

11.7 Buckling of a pipe with a cover - calculation

The largest buckling force that a duralumin pipe reinforced in the middle with a cover or insert (Figure 1.) will transfer is calculated using the following procedure:

11.7.1 We calculate the moments of inertia of the tube and the cover (insert) from the formulas:

where
D [mm] – outer diameter of the pipe
d [mm] – inner diameter of the pipe
D_pv [mm] – outer diameter of the cover (insert)
d_pv [mm] – inner diameter of the cover (insert)

11.7.2 We calculate ratios

and from the diagram in Figure 2 we subtract k

11.7.3 We calculate the largest buckling force from the formula

if we use the units l [mm], I [mm⁴], will be F [N]

FIG. 2