¶ Introduction
¶ Purpose, Objective and Scope
The Engine Bay is the main structure that integrates and transmits the thrust of Demo-B1 through the internal structure of Firehorn. It houses the bi-liquid engine, extending from both tanks to the lower section of the rocket, where it connects to the combustion chamber, ending with the boattail.
It therefore requires a particular emphasis on simulations and optimization due to the shear amount of forces experimented by the assembly during flight, and evidently, as a failure of any kind in one of the components of in this sub-assembly would compromise Firehorn flight trajectory.
¶ Definitions and Abbreviations
- EB: Engine Bay
- CFRP: Carbon-fiber-reinforced polymers
- ABR: Anti-Buckling Ring
¶ Applicable and Reference Documents
- Firehorn_Fluid_System
- 2024_C_ST_ENGINE-BAY_DJF
- 2024_C_ST_ENGINE_BAY_DDF
- 2024_C_ST_THRUST-PLATE_DJF
- 2024_C_ST_THRUST-PLATE_DDF
- 2024_C_ST_BOATTAIL_DJF
- 2024_C_ST_BOATTAIL_DDF
- 2024_C_ST_FINS_DJF
- 2024_C_ST_FINS_FEA
- 2024_C_ST_THRUSTPLATE_FEA
- 2024_C_ST_RRB_DDF
¶ Requirements
- 2024_C_SE_ST_ENGINE-BAY_REQ_01 Engine bay declaration of purpose
The Engine Bay shall host the combustion chamber, the boattail and the valves assembly located below the tanks. - 2024_C_SE_ST_ENGINE-BAY_REQ_02 Thrust plate
The Engine Bay shall transmit the thrust from the engine to the rest of the rocket through a fixed thrust plate. - 2024_C_SE_ST_ENGINE-BAY_REQ_03 Engine bay total length
The Engine Bay shall have a maximum total length of [950][+/-40]mm - 2024_C_SE_ST_ENGINE-BAY_REQ_04 Bay length
The Engine Bay shall have a bay length of [700][+/-20]mm - 2024_C_SE_ST_ENGINE-BAY_REQ_05 Boattail length
The Engine Bay shall have a boattail length of [250][+/-20]mm - 2024_C_SE_ST_ENGINE-BAY_REQ_06 Inside access
The Engine Bay shall allow for a human hand to access the valves inside. - 2024_C_SE_ST_ENGINE-BAY_REQ_07 Cable access
The Engine Bay shall allow for cables coming from the AV module to be connected to the valves. - 2024_C_SE_ST_ENGINE-BAY_REQ_08 Fins fixation
The Engine Bay shall allow for the fins fixation. - 2024_C_SE_ST_ENGINE-BAY_REQ_09 Fins loads bearing - Radial force
The fins fixation points shall withstand radial forces caused by the fins of up to [TBD]N with a FoS of [2]. - 2024_C_SE_ST_ENGINE-BAY_REQ_18 Fins loads bearing - Axial force
The fins fixation points shall withstand axial forces caused by the fins of up to [TBD]N with a FoS of [2]. - 2024_C_SE_ST_ENGINE-BAY_REQ_19 Fins loads bearing - Bending moment
The fins fixation points shall withstand bending moments caused by the fins of up to [TBD]Nm with a FoS of [2]. - 2024_C_SE_ST_ENGINE-BAY_REQ_10 Connection to the tank
The Engine Bay shall have a coupling point on the upper end. - 2024_C_SE_ST_ENGINE-BAY_REQ_11 Engine bay structure mass
The total mass of the Engine Bay structure shall be maximum [7000]g. - 2024_C_SE_ST_ENGINE-BAY_REQ_12 Structure type
The Engine Bay structure shall be internal so that its inside may be radially accessed. - 2024_C_SE_ST_ENGINE-BAY_REQ_13 Exhaust Isolation
The Engine Bay internals shall be insulated from the engine's exhausts. - 2024_C_SE_ST_ENGINE-BAY_REQ_14 Boattail Thermal Protection
The boattail design shall avoid thermal damage from the engine exhaust and radiation. - 2024_C_SE_ST_ENGINE-BAY_REQ_15 Engine Shock Protection
The boattail shall protrude at least [20]mm rearwards of the engine nozzle's end. - 2024_C_SE_ST_ENGINE-BAY_REQ_16 Impact absorption parts
The boattail shall be the only part to be damaged by the landing impact. - 2024_C_SE_ST_ENGINE-BAY_REQ_17 Impact characterization
The boattail shall absorb an impact corresponding to a touchdown speed of [8]m/s and an LV mass of [69]kg with a maximum inclination angle of [3]° with an additional FoS of [2].
¶ Functional Description
The Thrust_Plate is one of the main components of Engine Bay. It is responsible for the full integration and fixation of the Engine as well as the distribution of its Thrust through the Internal Structure. It also offers multiple fixation points the Boattail to attach to the Thrust_Plate.
¶ Physical Architecture
¶ Parts Tree
¶ COTS Parts Table
| Part Name | Number of Parts | Main Characteristics | Link to Data Sheet |
|---|---|---|---|
| Part_1 | x1 | Property_1, Property_2, Property_3 | Part_1_Datasheet |
| Part_2 | x3 | Property_1, Property_2, Property_3 | Part_2_Datasheet |
| Part_3 | x4 | Property_1, Property_2, Property_3 | Part_3_Datasheet |
| Part_4 | x6 | Property_1, Property_2, Property_3 | Part_4_Datasheet |
| Part_5 | x2 | Property_1, Property_2, Property_3 | Part_5_Datasheet |
| Part_6 | x9 | Property_1, Property_2, Property_3 | Part_6_Datasheet |
¶ SRAD Parts Description
The Engine bay is made up of multiple part as well as of a "standard" internal structre composed of 4 rods and a coupler on top. In this case the rods don't attach to another coupler at the bottom and instead attach themselves to the thrustplate.
¶ 216201_Thrust_Plate
¶ Description
The thrust plate has attachment point for the panels, the rods, the Boattail and Engine B1. The fixation to the rods are made with M10 screws. The thrustplate is made out of aluminium 2050 T-84.
| Part Name | Number of Parts | Main Characteristics | Link to .SLDPRT file |
|---|---|---|---|
| 216201_Thrust_Plate | x1 | attach the engine, attach the boattail, attach the rods | 216201_Thrust_Plate.SLDPRT |
¶ Technical Drawings
¶ 216203_Boattail
¶ Description
The Boattail is specially made to improve the aerodynamic performance of Firehorn, using a specific shape, it is made out of carbon fiber.
| Part Name | Number of Parts | Main Characteristics | Link to .SLDPRT file |
|---|---|---|---|
| 216203_Boattaile | x1 | cover the engine, improve aerodynamics |
¶ Technical Drawings
¶ 216204_Exhaust_Shield
¶ Description
The exhaust sield is used to thermally isolate the rocket from the heat of exhaust gases. It ised fixed to the nozzle of the B1 engine through a support piece, the exhaust shield is made out of inconel.
| Part Name | Number of Parts | Main Characteristics | Link to .SLDPRT file |
|---|---|---|---|
| 216204_Exhaust_Shield | x1 | thermally isolate the rocket from the engine |
¶ Technical Drawings
¶ Interfaces
The engine bay module has two main interfaces. First, it contacts to the boattail which links it to the exhaust shield as well. The second interface involves the engine B1 and the thrustplate where the engine is fixed to the trustplate. Fianlly the engine bay is connected to the rest of the the rocket through its internal structre and coupler above.
¶ Technical Budget, Margins and Deviation
SEE ENGINE BAY DDF
| Type of value | Units | Requirement Value | Actual Value | Deviation |
|---|---|---|---|---|
| Total Weight | kg |
¶ Design Constraints
¶ Constraints for Production
- Making sure the Boattail has the right shape through its production, since it is made out of carbon fiber
¶ Constraints for Operation
- Making sure the fins are properly aligned
- Not mixing the different screws together since most of them are M4 but with different length