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Tip: Bending Windscreen Support Weldment

goatflieg

Well Known Member
Most builders have had fit issues with weldments at some point. I had a fairly major one with my WD-814 windscreen support/roll bar. When I test fit it initially, it had the usual problems; the forward part of the triangular gussets were raised up a bit, and it didn't fit very well between the vertical tabs and the fuselage cockpit rails. If I snugged up one side, it left me with a 5/16" gap between the tab and the rail on the other side. That's quite a gap:
A81UHnNP9kZRaNMzieFafTzXfftAMZbIzP6mX-_TZdvhcSJVqTa9IfOmsuWxYy3_h_ykG1807vGkuSqJwUQIZe5dbGlGxfeOGF2K-kUjMfbzYItfMpHyH1fIr6Ac1oZsuln7_dZBMIquA0qThuKqS7nwxXmBQ2ANCY0WMYalUkqSTF2D1g3kE7YIR0d1e4BKRu2d3e1V9fDhENFsBbPeAQDLWHD3AUoL2b4QLYemuaQUOxminUHQeKVXidiCsF2ZVF9R55-WmDwUsqHpogl9QtaWqQHPH1cHJcWLi1tHcjN_Vk18mJvZAozTGJ5Shv7_AIC_Dwz-bklpug3U8OPmkbn0yYH9I30FF_H_EIpqyU_afDsKrrxJMxxAmnmLNewSWti2BGIQJ5XnO-pJnHkbNC13tA7jKbFc_lypQbN62cJeovhLqI7o6t7NeuA8M6LoYMuzlUBf7awrwzHhE-yAGOJN0pNxcY5Dty--pWZNAolMMZ5eXPXljYRCGETglXYG9sSkB0EakrCjkxTMGu1UlsoBYdMI5CwGpB5PlxuAZ1vIDRG1B5m6zEf_mzsCorsiXu1IaXdDLHbPDDr6NJAJ0pPjPRtjtAYq3EeETRylmA=w1461-h974-no

I checked for possible solutions here, but didn't find much info on the side-to-side issue, so I called Van's builder support. They said it was a common problem and that I should definitely spread the hoop slightly so that the tabs will fit the fuselage. We discussed various ways to do this. I had tried the "armstrong" method of holding one end down on a padded surface with my foot and pulling upward... but I knew right away my back wouldn't care much for that. So I did some thinking... and came up with this solution. I used my cherry picker; securing a chain around the base, wrapping tie-down straps around either side of the hoop and securing them to the base chain and lifting hook, and carefully extending the boom to stretch the hoop:
bAEagH5bN-NsLNlFt5a04sfM0mKIZnJ_td9Gcd76rJTufOz0YVli8OKS5Q04-ttbeA2OPFWeEG7X-ee4ibdHnhxBR1pIKIWxNuZPN1Ga_VJFF0fvXAE0TSzus6bJSF94kKf75sFwgTHKCWqDNgwr8ISbrblx6yoPYNs9Q3Uo0fETJmM5BTnULjo3XUyt974V8nlsEw_Mhob5Hh08ge--Zv6RHXCaxV_LKF5J_l3EUoSzFYezgNGdl8JoLzlxT2PQf5qgNprmJ3EnB2Otxu5JM89afGiDcrqiBjq9fEgJap0vOwtnH_x18MhijKMMrhl_GumvVcFFTdqDlxhh4f-hreILIlD-JfGaGmokbtNWdPvBgWL1k1elEhLIibXg2KcSIFzDx6_O7sAuV3i6ScE1q-qIKUAiUYY_9M9ExvPAw-BO1s0QoZw0qxuadXeeayrxcB7d3eTN_GOyuYY1bAAE18mVpOKIigDfcjwBGxnoRIDW0AH-LugZVc7Up8xRWI-F762YgqfNjdxgn30vI3kbi5YrPqWAgxn6fzSHYC_9r5JY_4wYSsS61I3_Ko9a2UUGLSnxwSxwtR19nORPPCsIFyjFe7lGak14tBieAAMAbQ=w1461-h974-no

I would stretch it a bit, let it spring back, and check measurements:
bbvzANd35-Caes26xMIYhs5SiIXy-yMv-mhMe-F9cxYVUpCYnPoO-1vawX8Sjt63YJDTAI86spM9MnRlWuFRkfFByOm9pVaR2ns-mYSNArv8E7Zk7o1lc84fBlPlz_CIazQskNBaJno1R0EVZYxO4qA26bOwugyb1VLBIfsUWQbnIqDuVqzvZeumk2kEtP9HNnRKVUe8D-KMPBNcE4isn_Ks2eZ9jdqJlFBE3gXo61VVvoHbPX0A-AKwRl7DTJ1XxfoqCMfGWcJVtF3a3MdCDd7xhdn65sTG9Ak9Puv2GleTOLAZP_RsIRhbnlGjPsPbXQi3v1bCLk1JuWIcNS_hjsETlBwI-Y2loQGvqFSpLtsSY7QR4IXgxnvNYGm6OzqtvEdRVDmHCnzM5ky3n4DHMMbopOZgAGssYRjPZoYotuRCaVpZDvncQOwjisBEcb-QzYZNfuMDtQlKFzEyuKs_n495VxA-o2wGG9znlqCwF0NeijpqfHRAeD2QmR3M_FUXF3TQ2DPboK4msRJaIWQNOE3YXZ4_4o01uZNell9DTMij20ItJFlFJvkZTPnD8ezbFWuU9YkXCFboNPbNQRzeXUbecE5bGwoCjI1NUEYCTg=w1461-h974-no

Eventually, after a couple bending sessions and a couple test-fits, I got it to fit just right:
1BPgclFJWy2WaIE5mT0V5elskzOahDoMrPh50C6P2-i60JhZClxmriqcxId2tXQl2EqOq9ACb9aH8ou6HzjD6iD6NH_d8nOH_6wgP6wUtGo1P6VUID3H2SIik0FhMDfBNnHCRABFEL4rvEyo6nD2W_ACcE2WcTcLDpPyPGItuAYhLx-vHhYHsykFML7kopyqOEWKRIV8YaHWjbovcKR6BuVNi8ACViPoGlqstXZR55REfqaZ9i7rC3yh6E4IRwZu3wwlHLJZgMIHoW3vo58poZgIkQeImgvpMhQfx4LapDapzJqE2Ef7pZ276HaoszFCfvEFkTpaC867ogmHNiwv3hOT4i4p5yS1bIDFKI1ybkGyJ_egVTJ2II_PeKeOPlV5Rtj2vMo2G7M7AhsEZGZCf7pwv_DZ0QmvoHTkB911UCh9fXuMxmFWL-AxusTQoZQ03JjKvPIiXyBwo9c_O7bZy0cZKcxgWEsuz-O0LbQQAggWP_tr7tvDSDlT7eoXtNJFn3OJhaEPAosS9WCm2R-FhzmTsk1TbKEC11zza1mx1ntNCKl17nAgcjcxaNApj_EiYJkgSAkrCDuAYfjEnZhYvNc928eDqiEPGevzv_LFUg=w1461-h974-no

I was so happy with the result, I wanted to share it right away. Van's said that the triangulated braces would probably pull together with the canopy rails with the bolts tightened; if I do any tweaking to those, I'll also share it here.
 
Yep, I did something similar and found that the bolts snugged everything up to the rails quite well once tightened down properly.
 
Good tip, Martin! The roll bar on my 6 slider needed to be tweaked the other way. Used my floor mount drill press as a big arbor press to make it fit!
Stewart Willoughby, 6 panel/wiring
 
New Guy Trying to Stretch WD-814

Martin, I have exactly the same gap between the rails and the WD-814. I also spoke with Vans Support and they told me the exact same thing. I attempted to use a hydraulic jack to stretch it and even with an inch and a half of movement it sprung back to it's original size. I got hesitant to push beyond that. Do you have any idea how far you had to go to actually have it retain some of the stretch?
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YUP, That top block is just screaming to dislodge under extreme pressure and turn your life into pure H***.
 
I used a set of heavy-duty ratchet straps to widen the support. They allowed me to spread the bar to about 26-1/4", which resulted in the desired final width of 24-3/8".

Don't pull on anything important, like the support beams in your hangar. ;)
 
YUP, That top block is just screaming to dislodge under extreme pressure and turn your life into pure H***.

Mike & Larry;
You are both absolutely correct!
My wife (who has nothing to do with building aircraft) opened the garage door and the first words out of her mouth were, "back the car out of the garage and move that thing away from the airplane"!
Humbling for sure. I tore my setup down and stopped for the night. I tend to get task focused:eek:
 
I used a set of heavy-duty ratchet straps to widen the support. They allowed me to spread the bar to about 26-1/4", which resulted in the desired final width of 24-3/8".

Don't pull on anything important, like the support beams in your hangar. ;)

Thanks Buck, I now know I just wasn't spreading it far enough to retain some of the stretch. The rollbar would obviously make a decent spring too!
 
No dog in this hunt, but y'all be careful using stretchy stuff to pull with. Those straps might not cut like a cable, but the hardware could take a major chunk out of your skull. A chain hoist would be a lot safer...
 
In Sept. 2012 I had to stretch also the windscreen support after welding two handhold (from stainless steel) to the bow.
AF1QipN_Vm5mCZR4xZ7nCJs-0KON1tvDXUTllwh_S8Tj
 
Last edited:
Most builders have had fit issues with weldments at some point. I had a fairly major one with my WD-814 windscreen support/roll bar. When I test fit it initially, it had the usual problems; the forward part of the triangular gussets were raised up a bit, and it didn't fit very well between the vertical tabs and the fuselage cockpit rails. If I snugged up one side, it left me with a 5/16" gap between the tab and the rail on the other side. That's quite a gap:
A81UHnNP9kZRaNMzieFafTzXfftAMZbIzP6mX-_TZdvhcSJVqTa9IfOmsuWxYy3_h_ykG1807vGkuSqJwUQIZe5dbGlGxfeOGF2K-kUjMfbzYItfMpHyH1fIr6Ac1oZsuln7_dZBMIquA0qThuKqS7nwxXmBQ2ANCY0WMYalUkqSTF2D1g3kE7YIR0d1e4BKRu2d3e1V9fDhENFsBbPeAQDLWHD3AUoL2b4QLYemuaQUOxminUHQeKVXidiCsF2ZVF9R55-WmDwUsqHpogl9QtaWqQHPH1cHJcWLi1tHcjN_Vk18mJvZAozTGJ5Shv7_AIC_Dwz-bklpug3U8OPmkbn0yYH9I30FF_H_EIpqyU_afDsKrrxJMxxAmnmLNewSWti2BGIQJ5XnO-pJnHkbNC13tA7jKbFc_lypQbN62cJeovhLqI7o6t7NeuA8M6LoYMuzlUBf7awrwzHhE-yAGOJN0pNxcY5Dty--pWZNAolMMZ5eXPXljYRCGETglXYG9sSkB0EakrCjkxTMGu1UlsoBYdMI5CwGpB5PlxuAZ1vIDRG1B5m6zEf_mzsCorsiXu1IaXdDLHbPDDr6NJAJ0pPjPRtjtAYq3EeETRylmA=w1461-h974-no

I checked for possible solutions here, but didn't find much info on the side-to-side issue, so I called Van's builder support. They said it was a common problem and that I should definitely spread the hoop slightly so that the tabs will fit the fuselage. We discussed various ways to do this. I had tried the "armstrong" method of holding one end down on a padded surface with my foot and pulling upward... but I knew right away my back wouldn't care much for that. So I did some thinking... and came up with this solution. I used my cherry picker; securing a chain around the base, wrapping tie-down straps around either side of the hoop and securing them to the base chain and lifting hook, and carefully extending the boom to stretch the hoop:
bAEagH5bN-NsLNlFt5a04sfM0mKIZnJ_td9Gcd76rJTufOz0YVli8OKS5Q04-ttbeA2OPFWeEG7X-ee4ibdHnhxBR1pIKIWxNuZPN1Ga_VJFF0fvXAE0TSzus6bJSF94kKf75sFwgTHKCWqDNgwr8ISbrblx6yoPYNs9Q3Uo0fETJmM5BTnULjo3XUyt974V8nlsEw_Mhob5Hh08ge--Zv6RHXCaxV_LKF5J_l3EUoSzFYezgNGdl8JoLzlxT2PQf5qgNprmJ3EnB2Otxu5JM89afGiDcrqiBjq9fEgJap0vOwtnH_x18MhijKMMrhl_GumvVcFFTdqDlxhh4f-hreILIlD-JfGaGmokbtNWdPvBgWL1k1elEhLIibXg2KcSIFzDx6_O7sAuV3i6ScE1q-qIKUAiUYY_9M9ExvPAw-BO1s0QoZw0qxuadXeeayrxcB7d3eTN_GOyuYY1bAAE18mVpOKIigDfcjwBGxnoRIDW0AH-LugZVc7Up8xRWI-F762YgqfNjdxgn30vI3kbi5YrPqWAgxn6fzSHYC_9r5JY_4wYSsS61I3_Ko9a2UUGLSnxwSxwtR19nORPPCsIFyjFe7lGak14tBieAAMAbQ=w1461-h974-no

I would stretch it a bit, let it spring back, and check measurements:
bbvzANd35-Caes26xMIYhs5SiIXy-yMv-mhMe-F9cxYVUpCYnPoO-1vawX8Sjt63YJDTAI86spM9MnRlWuFRkfFByOm9pVaR2ns-mYSNArv8E7Zk7o1lc84fBlPlz_CIazQskNBaJno1R0EVZYxO4qA26bOwugyb1VLBIfsUWQbnIqDuVqzvZeumk2kEtP9HNnRKVUe8D-KMPBNcE4isn_Ks2eZ9jdqJlFBE3gXo61VVvoHbPX0A-AKwRl7DTJ1XxfoqCMfGWcJVtF3a3MdCDd7xhdn65sTG9Ak9Puv2GleTOLAZP_RsIRhbnlGjPsPbXQi3v1bCLk1JuWIcNS_hjsETlBwI-Y2loQGvqFSpLtsSY7QR4IXgxnvNYGm6OzqtvEdRVDmHCnzM5ky3n4DHMMbopOZgAGssYRjPZoYotuRCaVpZDvncQOwjisBEcb-QzYZNfuMDtQlKFzEyuKs_n495VxA-o2wGG9znlqCwF0NeijpqfHRAeD2QmR3M_FUXF3TQ2DPboK4msRJaIWQNOE3YXZ4_4o01uZNell9DTMij20ItJFlFJvkZTPnD8ezbFWuU9YkXCFboNPbNQRzeXUbecE5bGwoCjI1NUEYCTg=w1461-h974-no

Eventually, after a couple bending sessions and a couple test-fits, I got it to fit just right:
1BPgclFJWy2WaIE5mT0V5elskzOahDoMrPh50C6P2-i60JhZClxmriqcxId2tXQl2EqOq9ACb9aH8ou6HzjD6iD6NH_d8nOH_6wgP6wUtGo1P6VUID3H2SIik0FhMDfBNnHCRABFEL4rvEyo6nD2W_ACcE2WcTcLDpPyPGItuAYhLx-vHhYHsykFML7kopyqOEWKRIV8YaHWjbovcKR6BuVNi8ACViPoGlqstXZR55REfqaZ9i7rC3yh6E4IRwZu3wwlHLJZgMIHoW3vo58poZgIkQeImgvpMhQfx4LapDapzJqE2Ef7pZ276HaoszFCfvEFkTpaC867ogmHNiwv3hOT4i4p5yS1bIDFKI1ybkGyJ_egVTJ2II_PeKeOPlV5Rtj2vMo2G7M7AhsEZGZCf7pwv_DZ0QmvoHTkB911UCh9fXuMxmFWL-AxusTQoZQ03JjKvPIiXyBwo9c_O7bZy0cZKcxgWEsuz-O0LbQQAggWP_tr7tvDSDlT7eoXtNJFn3OJhaEPAosS9WCm2R-FhzmTsk1TbKEC11zza1mx1ntNCKl17nAgcjcxaNApj_EiYJkgSAkrCDuAYfjEnZhYvNc928eDqiEPGevzv_LFUg=w1461-h974-no

I was so happy with the result, I wanted to share it right away. Van's said that the triangulated braces would probably pull together with the canopy rails with the bolts tightened; if I do any tweaking to those, I'll also share it here.

I have a similar issue right now! Thank you for posting! I was going to drill tomorrow and jam it in while temporarily spreading WD-814 , but seeing your solution, much better to bend it closer to final state than two temporally forcing it and keep all that internal tension on the body forever more.

Thanks!
 
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