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Engine selection and location


Engine of PIK-11 was Continental A65. So this and mainly its successors (up to O-200 D/AF) are obvious first options. Traditional aircraft engine.

This is located in front of fuselage, so that the alternative ensiges can be moved forward to maintain center of gravtity.

Specification of O-200 AF/D/X series is here.

Weight information needed is from here , here and here.

When calculating engine options, their center of gravity was estimated in relation to allowed center of gravity range midpoint. So engine and its accessories were put in such locations that the moment of all firewall forward parts was about the same as this reference engine. Accorging to Specificate (P8-0600-00023S) allowed cg range is X 695 - 807 mm, meaning that mid-point is 751 mm. Moment of all parts was calculated to, X 751 mm point. And when engine options moment was same, it means that aircraft total cg is about same.

Engine was located to rearmost possible location and propeller was mounted on 100 mm spacer. Component locations measured from above CAD model. Calculations are in the spreadsheet at bottom of this page. Firewall forfard mass is 111,4 kg and moment 132 kgm. Distance from propeller flange to firewall is 0,827 m.

Rotax 912 series

Bare engine is light, but need lots of accessoris around it. Some (oil tank) is rather far back. Distance from propeller flange to firewall is 1,013 m. So this is 186 mm longer than Continental.

Weight data is from here .

Propeller is installed with a 100 mm spacer. Component locations measured from CAD model below. Firewall forfard mass is 102,4 kg and moment 130,8 kgm.

UL 260

UL is the variant with longest prop saft. Component locations measured from CAD model above. Firewall forfard mass is 96,6 kg and moment 131,5 kgm. Engine is light, as it doest not need any supplemental parts around it. Distance from propeller flange to firewall is 0,934 m. So this is 107 mm longer than Continental.

Weight data is from here andUL installation manual.

Spreadsheet

ODS file.

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