• The Biplane Forum is a large global active community of biplane builders, owners and pilots. From Pitts to Skybolts, to older barnstormers, all types are welcome. In addition to our active community, our content boasts exhaustive technical information which is often sought after for projects and maintenance. This information has accumulated over the 12+ years the forum has been in existence.

    The Biplane Forum is a private community. Subscriptions are only $49.99/year or $6.99/month to gain access to this great community and unmatched source of information not found anywhere else on the web. We are also a great resource for non biplane users, since many GA aircraft are built the same way (fabric and tube construction).

Left Wing I

Beej

Creator of this place
Staff member
Administrator
Moderator
Joined
Jan 1, 2006
Messages
6,424
Reaction score
1,307
Location
Austin, TX
<TABLE cellSpacing=0 cellPadding=5 align=right>



Initial threading of ribs....


The spar butt fitting holes were marked out then drilled on the drill press. I made sure the drill press table was in-square to the drill bit.


Before threading through the ribs onto the spars, I marked reference points on the bench where the spars would be using the end of the bench as a straight line reference. Ribs were then threaded through. I then screwed down someL blocks to the bench along the reference points, which were then eventuallyclamped to the spars to keep eveything dead straight and flat on the 3/4 shims I used under the sparsso the ribs had clearance off the bench top.


The bench is dead square, this enables me to use the end of the bench as a square reference by screwing on a stop [basically a lip on the end]. The spars butt up to the stop, then you know everything is square without having to constantly bring a square into play.


The three compression strut ribs were then glued into place, the other ribs left loose for the time being [these need to be free-moving so you have drill clearance when drilling for 'drag wires at the ribs stationsjust glued]. Some builders like to use masking tape to hold the rib during curing, I like to clamp on a butt block to the side that's set upon the rib pencil line, then press 'home' the rib to it, clamping on a scrap piece on the other side which holds the rib against the butt block.


After curing, Idry fitted the spar butt fittingsand drew a pencil line around them, then removed them. The st.2 1/4 rib spar apertures were then widened to accomodate the 1/4 ply on the spars with a jigsaw.Feeding in the st.2 1/4 rib I then marked where the spar butt fittings will clash, removed the rib and notched the apertures with a hacksaw blade then jigsaw. On the front spar, the clevis pin bracket that mounts to the spar butt fitting also clashes with the rib slightly, so a little cutout has to be made for that too. The rib was then glued in place.





Cutout provision for spar butt fittings...

clamping up...
 

Latest posts

Top