19th September 2010 - Wing Struts

As per advice a small amount of dihedral (0.2 degrees) was introduced to both wings. This is to allow some shrinkage in the struts when the top is welded. Then the wing struts were attached to the fuselage and marked to length with the top level with the centres of the bolt holes in the strut attach brackets. The wing struts were then cut to length and the front and rear edges notched to fit between the brackets. Next sections of douglas fir were cut and planed to fit into the struts. These protect against any possibility of compression failure under negative G loads. Two sections of 1/2" x 0.065" tubing were cut to length the fit between the strut attach brackets and reamed out to take a 3/8" bolt to act as bushings at the top of the strut and then bolted into place. The end of the strut was then flattened to fit neatly against the tubing and the dihedral rechecked. With everything set up as required the struts were then tack welded to the bushing. The temporary wing supports were removed leaving the wings mounted via the three bolts which will hold them in flight. Finally it was all dismantled again. Next job is to final weld the top of the struts.

19th September 2010 - Setting the wing incidence

First today, the fuselage was levelled fore and aft and left to right and chocked in position. Then the wings were bolted into place and the dihedral set to zero as per the plans. All the measuring I'd done http://tailwindbuild.blogspot.com/2009/09/15th-september-2009-rib-rework.html paid off as the front and rear spar spacings exactly matched the fuselage brackets on both sides and the spar attach bolts slid comfortably into place in both the wings. A block was cut to create an exact level between the front and rear spars of the right wing . This wing had both the front and rear spar attach brackets bolted into position so provided the reference for setting the incidence of the left wing. On the left wing the rear spar attach bracket had not been drilled to the spar so the incidence of the left wing could be set precisely the same as the right. This was done and the bracket clamped into position and then drilled through the bushes in the spar and bolted into its final location.

18th September 2010 - Fuselage back from storage

Last week I set to and got the workshop clean and tidy so today I went and collected the fuselage from storage ready to mate the wings. I had intended to do this with the fuselage directly sitting on the drive and chocked up to get it exactly level so that it would be very solid to work on. However, I realised I was going to have to work underneath and that getting it in and out of the workshop was going to need two people so it seemed sensible to get it back on its wheels ready for starting work tomorrow. It hasn't been on wheels since it was primed and it looks much better than before in its smart white coat of paint.

17th August 2010 - The propeller arrives

A propeller! I managed to find a perfect second hand 69" x 63" Sensenich wooden propeller off a Diamond DA20-C1. This has the correct SAE #1 mounting and 3/8" holes to fit my engine and propeller spacer. The pitch should give my target 150mph cruise at about 2450 rpm. This will be very much a cruise prop so I will have to see how take off distances work out. Worst case it should be possible to rework the prop to reduce the pitch by a couple of inches to improve static rpm.

12th August 2010 - Wing structure complete

The workshop has disappeared under a layer of sawdust and wood shavings again but the wing structures for both wings are now complete and sanded ready for covering. The wingtips have come together well, carrying the profile of the main rib accurately as the wing tapers to the tip. You can just about see in the picture the way in which the top of the main spar stays flat throughout the wingtip but the lower edge tapers up. Next job is a major clean and tidy to create some room as I need to get the fuselage back from storage. I'm going to test mount the wings, finish the struts, and set the wing incidence before covering the wings. This will allow me to make any adjustments necessary as easily as possible. At the moment the rear spar attach bracket is not yet drilled to the spar on the right wing. This will give me a small amount of flexibility to set exactly the incidence of the two wings to be the same. Hopefully, all the measuring I did to make sure the spar spacings exactly match the fuselage will prove to be successful - we will see! It will probably be just into September before the next entry in the blog once I have retrieved the fuselage.

8th August 2010 - Wingtip spar caps and gussets

The construction of the structure of the wings is nearly complete. The wingtip spar caps have been glued in place and the gussets completed for the left wingtip - just the right wingtip gussets to go. Then comes the sanding of the wingtips. The challenge will be to blend the curves together to get smooth surfaces for the wingskins to adhere to.

6th August 2010 - Wingtip frames complete

Today I pinned, screwed, and glued the second wingtip frame together. Next job is to fit gussets to strengthen all the joints in the two wingtips and fit spar caps to the main spars and stub rear spars. Then it's back to sanding!