CONCLUSIONS

• The performance deficiences of the Horten IV were mainly due to:
   
• Large upward deflections of the elevons, which resulted in:
   
• High profile drag over the outer part of the wing
   
• High induced drag due to distorted lift distribution
   
• Separated flow over the aft-canopy due to high attitude of the center section
   
• The modifications done at MSU did not achieve their objectives:
   
• The aft~canopy separation was not eliminated
   
• The nose-skid fairing added vertical area ahead of the C.G., thus decreasing directional stability and hence prevented use of a more aft C.G. location for the performance tests
   
• In spite of these shortcomings, the Horten IV was a great machine, one of the world's best sailplanes of it's time