Average speed increase with the cowl and cooling plenum alone is 7-10 m.p.h.
The increased speed is made possible through improved internal and external aerodynamic flow. This is accomplished in part by a slightly longer cowl which requires either a 4" prop extension or an extended hub propeller.
A shorter length, carbureted version of the RV-6, 7, & 9 is available for use without a prop extension.
The inlet design, influenced by NASA funded research conducted at Mississippi State, resulted in a 40% reduction in size while ensuring improved cooling in climb and cruise configurations.
Overall drag is substantially reduced. Pressure loss in the upper chamber is negligible while cylinder head temperature variations are controlled uniformly to within a few degrees.
James Aircraft uses a cored composite lay-up in most of our cowls. This material reduces the weight of our cowls while strength and rigidity are substantially improved. This material may be used for rotary cowls provided specifications for length of core, oil and inspection doors can be provided by the builder. Otherwise, rotary cowls and RV-4 cowls will be constructed as a "flat-glass" layup.
The induction system for the fuel injection servo provides approximately one inch of mercury increase over ambient at 5000 feet density altitude.
The Cowling is available for the IO-320 through IO-360 200 horse power engines, as well as carbureted engines O-320 through O-540. The Cowling Kit, except for the RV-4 and the Shorty versions, includes the upper and lower cowling with pre-molded inlet scoop, three CNC machined anodized aluminum inlet rings, rubber seal with seal cement. Induction kits are sold separately. The RV-4 and the Shorty RV versions all use the standard Van's air induction.
Cowling Cost: RV-4 thru RV-9--$950.00
Shipping is paid by customer to freight company upon delivery. We will notify you prior to shipping as to prices and options.
The new box is designed for use with either carburetors or 4 bolt (3.25"center to center) flat flange injectors. It will not work with Airflow Performance "pipe flange" type injectors without a custom adaptor.