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Since I replaced all the sheet metal at the door opening, I need to re-mark the plumb bob top location on the door header. What other leveling procedure can I use to set the fuselage level and mark the string point?
I don’t recall the drawing number for the centerline dimensions to find level. On my Pacer I can’t use the plumb bob to level the fuselage due to the seaplane doors and didn’t replicate the hole in the door opening on the right side to hang the plumb bob from. And I formed Kydex that wraps around the tube covering the plumb bob punch mark. Also I didn’t want to disassemble the interior pieces just for leveling. What I did was mark the door opening on both front door posts and the tail. Then to level I use a rotary laser level that is accurate 1/8” at a thousand feet. I shoot through the doors and tail. I think you can do the same thing by marking the door post on the right side and window trim on the left side XX” above the centerline and use the same dimension on the tail. I’ll look up the drawing if you’d like and make recommendations on where exactly the level lines should be placed. Also using the firewall and tail post you may find level fore and aft but not side to side.
I have the drawings, so if you find the number, let me know. Interested in your dimensions too, I also did seaplane doors on my Pacer, and likely will adopt your leveling method.
The engine mount to the firewall bolts should be side to side level. Excepting for some weld distortion, the tube over the bungees just under the front of the seat should also have been level side to side. With all the years these things have been making unknown history, you may just side to side level at the wing spar to upper fuselage attach bolts.
Drawing number 12510 shows the centerline. Center line is 28” in a vertical line down from centerline of the front wing spar bolt hole, the second dimension is 26-1/2” down from centerline of the rear spar bolt hole. Neither dimension follows the slightly angled fuselage tubing. The rear centerline is one inch above the centerline intersection of the lower longeron and rear tube of the vertical stabilizer. I laid out the door jambs and marked my fuselage at those dimensions using a 3’ straight edge and clamps to sneak up on hitting the dimension exactly. If you don’t have the left side door, I’d subtract xx number of inches from the front two points to get up to the window frame where you can add a level mark or center punch. Then add the same number up the rear vertical stabilizer tube.
Lateral level is not specified in the TCDS for our aircraft. I may have only done it once and that was on a Helicopter. Simply dropping a plumb bob with line over the leading edge and lifting the tail until the plumb bob is aligned with the center of the MLG axle. I was taught to "snap" a chalk line down the entire length the fuselage on the hangar floor. You can then measure the distance of the components as from the Datum as needed.
Todd
Last edited by Vagabondblues; 04-22-2024 at 12:19 PM.
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Alternate fuselage leveling
Originally Posted by Vagabondblues
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