A series of experiments were carried out during seasons 2005/2007 at Gemmiza Agricultural Research Station, Tanta, El-Gharbia Governorate, Egypt. The objectives of these experiments were to study the effect of some physical and engineering properties of some Egyptian varieties of corn on the performance of the pneumatic drill machine. The results indicated that, the maximum values of the physical and engineering properties were in case of corn TC 310. But the minimum values were in case of corn

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... ryana. At the same time, the moderate values were in case of corn SC 10. On the other hand, the levels of tractor speed which give the conformity fan air speed with suction air velocity and lowest value of fuel consumption were determined. The results showed that, the fan air speeds were 225, 249 and 247 r.p.m under corn ryana, SC 10 and TC 310, respectively. The fuel consumption rates were 3.4, 3.7 and 3.9 l/h in case of corn ryana, SC 10 and TC 310, respectively. From the obtained data the study recommended that, the suitable diameter seed plate holes were 7, 7 and 5 mm for corn SC 10, TC 310 and ryana, respectively. Also, the optimum suction air speeds were 12, 14 and 15 m/s for corn ryana, SC 10 and TC 310, respectively. Whereas, the highest percent of seeds holding in seed plate holes were obtained at these speeds. On the other hand, the appropriate operating speed of tractor was 3 km/h.