Januray 1998 Engineering Notices
The following Enginering Notices apply to serial numbers 326 and below:
Refer to Drawing # 18 firewall detail.
During the assembly of the Bearhawk I am now building I found that the 7 1/2" dimension was about 1" too high. This dimension should be reduced to about 6 1/2". See corrected drawing below.
This change is needed to keep a good line from the top of the nosebowl to the top of the instrument panel and increase the tunnel area at the bottom of the firewall for better engine cooling.
Please note the size of the firewall has not been changed, it has just been positioned lower on the airframe.
Also note that depending on the type of engine you use, the shape of your nosebowl and the height you make the instrument panel may affect the vertical location of the firewall.
The minimum clearance of the engine and related components to the cowl is 1/2".
Tailplane Incidence Adjustment:
Refer to drawing # 19.
Change the 3 7/8" dimension to 3 1/2" as shown in the drawing.
This change will allow for more horizontal stabilizer adjustment range to accomodate various engine installations.