It is shown that the curved lifting line theory for a nonplanar wing is not deficient, at least for evaluating the span efficiency factor. It is exactly shown that the span efficiency factor of a hemielliptic front view GEW e(λ, ε) is sym metric for exchange of λ ?? 1/λ, where λ denotes the height ratio, and ε the tip gap angle parameter. This assures the result in our previous paper, from another viewpoint. A simple method is presented, for analysing a nearly flat GEW.
Results of investigations on powder rockets using LiAlH4 as energetic fuel are discussed. Theoretical evaluatioll of Isp shows that maximum Isp is 350sec for LiAlH4-H2O2 (90% aq) system in vacuum with nozzle expansion ratio 40. Experiments of the powder rocket system are conducted to study the problems concerning to the feed system and the combustion efficiency. Tested fuel is LiAlH4: polyethylene of 1:1 mixture which is hyperbolic with H2O2. Firing tests with 4-5sec of duration have shown relatively smooth operation. 90% of efficiency has been derived with respect to speific impulse perform-ance despite small chamber size and low chamber pressure in the experimental conditions.