<p>9-cylinder Radial Engine Dummy for Model Airplane.&nbsp;</p><ul><li>Outer Diameter: ca. 170mm&nbsp;<br>&nbsp;</li><li>Fits 65mm Spinner</li></ul><p>It can be scaled up or down, according to your model size.<br>I have used it for a Samson Pitts 70e. See pictures.<br>There are holes for metal rods that can be inserted to represent the valve pushrods. I have used aluminium welding filler rod.&nbsp;<br><br><strong>Caution:</strong> I had to block the gaps between the cylinders using balsa wood. If you leave them open, all of the air flows through the cylinders and the brushless motor gets very hot. If you block the gaps from behind, some air gets forced through the center hole and it cools the brushless motor much better.</p>