AVRpt1

1
Individual Student Air Vehicle Design Reports
AVRpt-1
2
Air vehicle report format

• 1.0 Requirements (list)
• 1.1 Overall system
• 1.2 Air vehicle specific
• 2.0 ConOps Description
• 2.1 Overall ConOps (include sketch)
• 2.2 Air vehicle role (explain the function)
• 3.0 Air Vehicle Description
• 3.1 Physical description
• Overall description including key features
• Configuration sketch (PowerPoint, see
  description)
• Configuration data (PowerPoint, see description)
• 3.2 Functional description
• How it works (i.e. how it does the mission)

OK for team to prepare one input for use by
entire team
AVRpt-2
3
Report format contd
3.3 Performance estimate (PowerPoint, see
description) - Summarize and explain 3.4
Performance methodology 3.5 Parametric
comparisons to confirm estimates 4.0
Configuration rationale 4.1 Background including
configuration history 4.2 Trade study
substantiation including at a minimum AR,
W0/Sref, Lf/Df, Vcr, BPR (if TBFan) 5.0 Risks and
Issues 5.1 Risk assessment and rationale 5.2
Sensitivities to airframe weight (?10) and
overall drag (?10) 5.3 Areas for improvement
OK to create one input for use by entire team
AVRpt-3
4
Configuration sketch

• Configuration 2-view (profile and planform)
• Approximately to scale (see example problem)
• Configuration data (see example problem)
• Show location of key features including
• Engine
• Landing gear
• Payload
• Sensor, communications and expendable as
  appropriate
• Fuel tanks
• Center of gravity
• Wing a.c.

AVRpt-4
5
Configuration data

• Geometry data
• Sref
• Swet
• Span
• AR
• Wing t/c
• Fuselage length
• Fuselage Lf/Df
• Fuselage w/h
• Tail configuration
• HT area
• VT area
• Weight Data
• Gross weight
• Empty weight
• Payload weight
• Fuel weight
• Wing

• Propulsion data
• Number of engines engine type
• T0 or BHP0 and TSFC0 or SFC0
• Propulsion weight (uninstalled)
• T0/Weng or Bhp0/Weng
• BPR (if appropriate)
• Fsp-gg, Fsp-fan, f/a
• Airframe data
• Unit weights
• Waf/Sref
• Volumes
• Available, required by component and margin
• Airframe weight
• Landing gear fraction weight
• Propulsion weight (installed)
• Systems other fraction weight
• Misc. weight
• Weight margin

AVRpt-5
6
Performance estimate

• Overall
• Maximum range
• Maximum endurance
• Takeoff distance (ground roll)
• Initial rate of climb
• Ceiling altitude
• Landing loiter
• Landing loiter speed
• Design mission
• Operating radius
• Operational loiter or dash distance
• Cruise speed and altitude
• Loiter speed and altitude
• Maximum speed at cruise altitude
• Fallout mission
• Operating radius
• Operational loiter or dash distance
• Cruise speed and altitude
• Dash speed and altitude

AVRpt-6
7
Typical shortfalls

• Requirements
• Overall system Dont blow it off with a short
  list of overall requirements ignoring key design
  requirements such as definition of ID,
  ceilings/visibility and weather, etc.
  Recommendation go back through lessons and
  compile complete requirements list. Put them in
  the report
• Air Vehicle Same comment. Document key air
  vehicle requirements such as payload weights,
  volumes and power. Recommendation go back
  through lessons and compile complete air vehicle
  requirements list. Put them in the report
• Defined vs. derived many ignoring the
  instructions
• Other issues team member operational loiter and
  payload requirements should not be different (for
  same mission function)
• ConOps
• Dont focus on air vehicle. Dont forget to
  describe how system works. Under air vehicle
  role Describe from takeoff to landing

AVRpt-6
8
Typical shortfalls contd

• Air Vehicle Description
• Physical description Drawings must be reasonably
  to scale. E.g., no drawing with similar span and
  length but dimensions show 21 differences or
  tail areas that dont correlate (25 tail area
  drawn at 10). Dont show tail definitions tail
  that ignore stability, i.e., V-tails that dont
  meet horizontal and vertical area reqirements
  unless described as intentionally unstable and
  penalties taken accordingly. Prop size and
  dimensions cant be ignored. Inlets and nozzles
  must be shown. Center of gravity cant be behind
  aerodynamic center unless defined as fly-by-wire,
  or even worse, shown behind main landing gear.
  Installed payload weight must be used.
  Non-circular cross sections must not be drawn at
  w h De sqrt(wh) ? w Desqrt(w/h), h
  De/sqrt(w/h)
• Performance estimates Performance table must
  match spreadsheet, dont have unexplained
  thrust/drag/weight factors, have consistent
  performance criteria or design loiter/ingress
  distances. Check T0/W0 ? TOP or Ps ? 5, Cl-cr lt
  stall margin, etc.

AVRpt-6
9
Typical shortfalls contd

• Air Vehicle Description (contd)
• Performance methodology the objective is to
  convince me that your understand the spreadsheet
  methodology and limitations not design in
  general, including Raymer methods. Methodology
  description needs to describe aerodynamics,
  weights, propulsion, geometry, individual
  performance methods as well as overall
  performance sizing/estimation approach
• Aero Oswald efficiency is function of AR and
  sweep. Use graphic as source data not parametric
  correlation
• Weight Provide basis for selection/assumption of
  airframe unit weights, explain or cite rationale
  for other weight factors.
• Propulsion Either use my model inputs or provide
  solid rationale for using something different
  (note - V0 is not a design variable). Allowable
  variable changes are f/a (to match SFC0 or TSFC0
  data) and FanFsp ( as function of BPR).
• Geometry model inputs Model inputs must match
  configuration or vice versa. E.g. no Kvol2 .7
  with buried-aft engine or VKol2 0 with wing
  mounted engines.

AVRpt-6
10
Typical shortfalls contd

• Air Vehicle Description (contd)
• Performance correlations must address
  fundamental aerodynamic, weight and propulsion
  performance parameters (key elements or Breguet
  equation)
• Compare at a minimum L/D, Waf/Sref and TSF0 or
  SFC0. Other parametric comparisons are useful
  but dont replace the big three
• Oswald efficiency vs. AR is not a parametric
  comparison, it is an input variable
• Provide parametric plots, dont expect reviewer
  to go look them up and/or visualize results
• Dont blow off differences. When model results
  dont fit parametric data, dont explain away
  differences unless you have a really strong case.
  Use the parametric comparisons to correct the
  model
• Configuration rationale
• Trade study results must be for consistent levels
  of performance to include operational loiter,
  minimum Ps, V-cr vs. stall margin, etc. Do not
  simply change model inputs and record outputs.
  Rerun/reconverge model for consistent performance.

AVRpt-6
11
Typical shortfalls contd

• Risks and issues
• Sensitivities to airframe weight and drag must be
  treated like trade study variable. I.e. model
  must be rerun/reconverged for consistent
  performance

• Individual Student Design Report Grades
• Papers and grades will be available Monday
• I will fly them down on Sunday, Jeremy will have
  available for you to pick up on Monday morning

AVRpt-6