▁is ▁available ▁as ▁plans ▁only . ▁The ▁power ▁range ▁specified ▁is ▁, ▁with ▁the ▁ ▁largest ▁engine ▁specified ▁the ▁ ▁Rot ax ▁ 2 7 7 . ▁The ▁▁ 2 si ▁ 2 1 5 , ▁ ▁H irth ▁F - 3 3 ▁and ▁ ▁Z eno ah ▁G - 2 5 ▁have ▁also ▁been ▁used . ▁ ▁The ▁design ▁was ▁profession ally ▁engine ered ▁and ▁incorpor ates ▁a ▁very ▁clean ▁cant ile ver ▁wing ▁that ▁results ▁in ▁a ▁ 1 2 : 1 ▁gli de ▁ratio . ▁The ▁control ▁system ▁is ▁two - axis , ▁using ▁only ▁elev ator ▁and ▁rud der ▁controls , ▁roll ▁being ▁introduced ▁by ▁rud der ▁via ▁a ▁gener ous ▁di hed ral ▁angle . ▁The ▁elev ator ▁is ▁stick - control led , ▁while ▁the ▁rud der ▁is ▁controlled ▁via ▁conventional ▁aircraft ▁ped als . ▁The ▁aircraft ▁is ▁st all ▁and ▁spin ▁proof . ▁Report ed ▁construction ▁times ▁are ▁ 4 5 0 – 6 0 0 ▁hours . ▁ ▁Pl ans ▁were ▁initially ▁sold ▁direct ▁by ▁the ▁designer ▁and , ▁in ▁the ▁early ▁ 2 0 0 0 s , ▁by ▁the ▁V int age ▁Ult ra ▁and ▁Light plane ▁Association . ▁Later ▁the ▁designer ' s ▁son ▁market ed ▁the ▁plans ▁and ▁this ▁is ▁the ▁current ▁source . ▁ ▁Spec ifications ▁( S ky ▁P up ) ▁ ▁See ▁also ▁ ▁References ▁ ▁External ▁links ▁Ph oto ▁of ▁a ▁Sky ▁P up ▁ ▁Category : 1 9 8 0 s ▁United ▁States ▁ul tr al