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James Aircraft

Engine Cowlings

We manufacture engine cowlings for the RV-4, 6, 7, 8, 9, 10 and 14.  Our design and manufacturing process is the result of over twenty years of product development and improvement.

Our cowls are constructed using an advanced material system that maximizes strength and stability while at the same time
minimizes weight. We use a three dimensional fiberglass core material not the older style phenolic "honeycomb" paper core which mitigates concerns about delamination over time.

Our circular inlet design comes from a NASA funded study that was conducted by Mississippi State University. The study influenced our design and resulted in an increase of cooling flow and reduction of drag penalties.
The inlet area is approximately the same as that of square or rectangular inlets traditionally used for horizontal, opposed aircraft engines.

The cowlings are available for both updraft and forward facing induction systems, fuel injected and carbureted IO-320 through IO-360, 200 horsepower angle valve engines. The cowling kit includes the upper and lower cowling with pre-molded inlet scoop, three CNC machined aluminum inlet rings, oil inspection door, rubber plenum seal and sealant. Induction filtration kits are sold separately. The RV-4 and the "Shorty" standard Van's length RV versions all use the standard Van's air induction.

Engine Plenums

Our plenums are constructed using an epoxy resin. They are available for 320, 360 angle and parallel valve, and 540 engines and may be used on many different aircraft.

Our plenum optimizes airflow needed for cooling drag reduction and cooling flow. The plenum system seals up far better than traditional baffling allowing a better buildup of high pressure air and more even airflow over your cylinders for better cooling. Cylinder head temperatures are closer to uniform and the cooling drag reduction can yield speed increases.

Ram Air Induction

Flying with unfiltered air will most likely lead to costly repairs. Our systems filter "full time" using a very low restriction conical shapped K&N reusable filter that provides an additional one inch of manifold pressure over ambient at 5,000' density altitude. These systems are designed specifically for use with our cowls but may be adapted to many other aircraft.

Available versions serve forward mounted, parallel sumps, and updraft, injected or carbureted engines.

Aluminum Inlet Rings

Precision machined 6061-T6 aluminum inlet rings come with our cowls or can be purchased separately. These rings are designed to fit our cowlings however they can be used for other installations.

The following sizes are available for purchase:

  • X-Large (O.D. 6″; I.D. 5-7/16″)
  • Large (O.D. 5-1/4″; I.D. 4-5/8″)
  • Medium (O.D. 4-3/8″; I.D. 3-3/4″)
  • Small (O.D. 3-1/2″; I.D. 2-7/8″)
  • Full Set (2 Lg. or Med. and 1 Sm. ring)

Wheel Pants:

Our wheel pants are pressure recovery type and are substantially smaller in cross-sectional area than others available. This results in a drag reduction which can yield speed increases over other comparable wheel pants either being sold separately or coming with your kit. They are lightweight and strong.

Wing Root fairings

We sell wing root fairings for the RV-4. These fairings provide an intersection radius similar in appearance to the Curtiss P-40. The trailing edge is slightly extended to provide a clean departure.