text: The detonation properties of a fuel are de- 
  termined by the basic molecular structure of 
  the fuel and the various additives. The fuel 
  detonation properties are generally specified 
  by the antidetonation or antiknock qualities of 
  an octane rating. Since the antiknock proper- 
  ties of a high quality fuel may depend on the 
  mixture strength, provision must be made 
  in. the rating of fuels. Thus, a fuel grade of 
  would relate a lean mixture antiknock 
  IIS/ 
  rating of 115 and a rich mixture antiknock 
  rating of 145. One of the most common opera- 
  tional causes of detonation is fuel contamina- 
  tion. An extremely small contamination of 
  high octane fuel with jet fuel can cause a serious 
  ,decrease in the antiknock rating. Also, the 
  the 
  contamination of a high grade fuel with 
  next lower grade will cause a noticeable loss of 
  antiknock quality. 
  
  cruise power is the upper limit of power that 
  can be utilized for this operation. Higher air- 
  flows and higher power wirhout a change in 
  fuel-air ratio will 
  intersect the knee of the 
  detonation envelope. 
  
  The primary factor relating the efficiency of 
  operation of the reciprocating engine is the 
  brake specific fuel consumption, iWE%, or 
  simply c. 
  Brake suecific fuel consumution 
  I 
  
  engine fuel flow 
  = brake horsepower 
  
  lbs. per hr. 
  BHP 