021 01 Airframe & Systems

• Carries all the forces: Skin, Bulkhead
• Parts used: SKin, Former, Bulkhead
• Can absorb forces 
• Has space for pax and cargo
• Negativ: If structure is damaged, it is weakened and can ben

• "Advanced" Monocoque
• Stringers strengthen the skin. They are riveted on to the skin
• Longerons further strengthen the skin in longitudinal direction
• Force is absorbed by: Skin, Bulkhead, Stringer, Longeron, Former

Main Parts:

• Spar
  • Caps
  • Web
• Torsionbox
• Formers
• Stringers
• Ski

• Integral
  • Everything out of one part
  • If something breaks the whole thing has to be replaced
• Differential
  • Single members form one part
  •  Members can be replaced if damaged
  • Members break as seperately

An A/C has a defined minimum number of flying hours or cycles which should elapse before a major structuralfailure occurs

• Multiple load Paths --> Loads are shared by additinal members
• If one part fails the load is carried by the adjacent member for a limited period of tim

EAA:

• CS25, Big A/C
• CS23, Small A/C

FAA

• FAR25, Big A/C
• FAR23, Small A/C

1. L_max (Last cycle), maximum Load, Designlimit
2. Proof Load (no Deformation), L_max * 1.125
3. Ultimate Load (below that no failure), L_max * 1.

• Dehnung
• If acting force is string enough to change the shape of the object

Condition        Probability         Effect

Minor              Frequent            Normal Operation

Minor              10^-3                    Operating limits, Mergency Procedures

Major              10^-5                    Difficulties for Crew

Hazardous      10^-7                    Extended Workload, Serious or fatal injuries in small numbers

Catastrophic   10^-9                    Total Hull Loss, Multiple death

• Spreads load of a particular Structure over a large area
• Designed so that damage can be detected during normal inspection cycles before a failure occurs

• Fail safe
• Safe Life
• Damage Toleran

• Integral Construction
• Differential Construction
• Composite-/Sandwich-Structur

AMount of Fuel for one HP in one hour

Diesel and Kerosene are generally speaking the same, the main difference is the freezing point

Both products have a specific gravity between 0,81-0.86 kg/l.

Diesel has a Flashpoint starting at +25°C and a lowest freezing Freezing Point of -25 °C (e.g. winter diesel). Kerosene has the highest freezing point starting at -40°C.

Freezing Point:

• Jet A: -40 deg C
• Jet A-1: -50 deg C
• Jet B: -60 deg C

Flash points:

• Jet A: 38 deg C
• Jet A-1: 38 deg C
• Jet B: 18 deg C

Specific gravities at 15.5 deg C:

• Jet A: 0.807
• Jet A-1: 0.807
• Jet B: 0.764

Blue

The flash point is the lowest temp. at which the fuel gas mixture can ignite.

The fire point is the lowest temp. at which the fuel gas mixture can sustain combution by itself through vaporisation.

athe auto ignition temperature is the temp. at which a fuel spontaneously ignites without the presence of an ignition source.

As aviation fuels are a mixture of hydrocarbons, these hydrocarbons can form ice crystals. The freezing point is the temp. at which the last ice crystals formed by hydrocarbons disappear.

The octane rating is the measure of the fuel's resistance in respect to detonation.

AVGAS 100LL has a higher octane rating than MOGAS (100 vs. 98) and thus has a higher resistance to auto-ignite.

Vapour locks in pipelines

Volatility is the measure of a fuel's tendency to change state from a liquid to vapour

The vapour pressure is the term used to indicate the ambient pressure at which the fuel vaporises. A high vapour pressure indicates that fuel vaporises at high atmospheric pressure.

When aviation gasoline is stored and has a chemical interchange with air, hydrocarbons vaporise.The fuel can oxidise. Two of the biproducts of this oxidation are soluble gums and insoluble black particulates. The particulates and gums can block fuel filters or clog up carburator jets and narrow bore pipes.

Pascal's Law is a principle in fluid mechanics that states that a pressure change at any point in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere.

P = F / A and P₁ = P₂ and Volume = A * D

F₂ = 60 N

D₂ = 20 in 

 

Health precatutions to avoid contact with the fluid.

• must flow with minimum resistance
• must be incompressible
• must have good lubricating properties
• must inhibit corrosion and not attack seals
• must not foam in operati

With open center systems, multiple hydraulic actuators are supplied simultaneously.

With closed center systems, hydraulic actuators can only be used one at a time.

• Active: pressure is cont. generated by a pump
• Passive: pressure is only generated, when the hydraulic operating unit is used, e.g. wheel brake.