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Windshield Bow

PostPosted: Thu Oct 04, 2012 3:38 pm
by Andy Walker
Hey all...

Starting to look at my windshield and canopy, and specifically the windshield bow. It looks like my bow was cut oversized, so that it could be trimmed to fit. However, it looks like the ends of the bow have to be bent straight to engage the attachment holes in the longerons. Until you bend the ends, the bow can't be put in place to test fit. So how does one decide where to bend, without first knowing how long the bow needs to be? Should I fit the windshield in place, then measure/bend/cut the bow as necessary, or is there a better or more accurate way?

Re: Windshield Bow

PostPosted: Thu Oct 04, 2012 8:26 pm
by chrisyk
Hi Andy

I don't have the prints in front of me, but the drawing gives a radius for the bow (17" I think?). I laid out a half circle on the table, with the base line being where the longerons would be. You don't need to bend the ends of the bow very much to get them to fit into the longerons. After you've tweaked the ends you can check the radius of the bow, mark out where the screw holes go etc. on the table.

I found I had to raise the bow slightly to remove a bit of a dolphin nose when I was fitting the canopy. This may not be necessary in all cases. I don't know why mine needed it as I used the full width of the factory supplied windshield across the bow. I had to trim the nose end of the windshield about 1/2 inch on both sides to get that to fit.

Chris
Sonex #1226

Re: Windshield Bow

PostPosted: Thu Oct 04, 2012 8:35 pm
by Andy Walker
Thanks Chris. I'm thinking of making the straight parts on the ends of the bow 1.5" instead of 1" as the plans specify...that way I can have some more travel to set the windshield height, and can always trim it back later.

Re: Windshield Bow

PostPosted: Fri Oct 05, 2012 11:11 am
by N111YX
Andy, first of all, I would not use the windshield as a template. You'll want the correct bow then fit the windshield. There more dimensional variables that would mess things up versus having the bow hanging in space as a reference.

As for the bent ends, I would try to establish your desired bow height (perhaps using string from nose to points aft), then make the bends from there. I think you'll find later on the exact location of the bends is not too critical.

Re: Windshield Bow

PostPosted: Fri Oct 05, 2012 1:03 pm
by kmacht
I just finished fitting my canopy and windshield last night (no cracks as of this morning). I fit the windshield by trimming to the sonex pre-grooved length and then trimmed down the sides. For the sides I left the back end the full lenght/height it came from the factory. I then trimmed the front end of the sides down until it fit nicely over the upper firewall strap. The cuts down the sides were triangular with it starting at the back edge and tapering larger as it went to the front. After that I screwed the windshield down to the firewall strap and down the sides. This set the basic shape of the windshield. I then went and fit the bow to the rear side of the windshield. As you said they come oversize from the factory. I had to cut about an inch and a half off of each side . Mine also seemed to have the last six inches completely straight so I had to work them into the same curve as the rest of the bow. After that I just pushed the bow down into the longeron holes and then raised it up to meet the windshield and screwed it down. The shape seems to be right as I just finished up the canopy and everything seems to line up nicely without any bottlenose. Now getting the canopy bow to match the turtledeck shape is a whole other story.

Keith

Re: Windshield Bow

PostPosted: Fri Oct 05, 2012 2:44 pm
by Andy Walker
kmacht wrote:I just finished fitting my canopy and windshield last night (no cracks as of this morning). I fit the windshield by trimming to the sonex pre-grooved length and then trimmed down the sides. For the sides I left the back end the full lenght/height it came from the factory. I then trimmed the front end of the sides down until it fit nicely over the upper firewall strap. The cuts down the sides were triangular with it starting at the back edge and tapering larger as it went to the front. After that I screwed the windshield down to the firewall strap and down the sides. This set the basic shape of the windshield. I then went and fit the bow to the rear side of the windshield. As you said they come oversize from the factory. I had to cut about an inch and a half off of each side . Mine also seemed to have the last six inches completely straight so I had to work them into the same curve as the rest of the bow. After that I just pushed the bow down into the longeron holes and then raised it up to meet the windshield and screwed it down. The shape seems to be right as I just finished up the canopy and everything seems to line up nicely without any bottlenose. Now getting the canopy bow to match the turtledeck shape is a whole other story.

Keith


Hmm...yours sounds different from mine...mine has no straight area, it's a constant curve; I'm going to have to bend the bow straight on each end once the proper height is determined.

Thanks everybody!