Firewall - Thrust Lines - Where are they? Horizontal and Vertical

Question: I am installing my engine. Where are the thrust lines on the firewall?

Answer: The horizontal thrust line normally appears on the forward face of the firewall or you draw the horizontal thrust line on the forward face of the firewall yourself following location instructions contained in the documentation that came with your model.

If there is no horizontal line indicated on the firewall and you are unable to locate the location of the line in the reference material there is an easy way to position the horiztonal thrust line youself. To do this, fit your cowl over the fuselage. Look at the cowl from the left and right sides and adjust the vertical angle of the cowl to align with the fuselage. There should not be any sharp drop or rise in the silhouette profile of the fuselage as you move your eye along the fuselage and over the cowl. Once you have the cowl in place, look through the front hole where the crankshaft is going to protrude. Mark the horizontal thrust line on the firewall so that it is evenly located up and down with respect to the hole in the front of the cowl.

The vertical thrust line lies up and down through the middle of the firewall. If it is not shown, you can simply draw it into place. Make sure it is in the middle.

You may also find this information on our web site. Look for the links to your model, then the link to the detailed information and browse down to the engine section. The position of the horizontal and/or vertical thrust line may be stated there.