Hatz Biplane Association

I got a message the other day from Ron Southard with a question about the windshield frames I'd used on NX1279. We decided this might be a good subject for the forum in case others were interested in the process.
The pictures shown below were taken several years ago during the restoration of a TravelAir and the windshields I used on my Hatz were just scaled down versions of this design.
Whatever curved shape you intend to use, first make a paper then aluminum pattern to develop the shape, roll and installed angle of your windshield. The ones I built for NX1279 are a little bit shorter than optimum for a wind free cockpit, particularly in the front. The trade offs are appearance, drag and cockpit access.
In any case, once you've developed your curved windshield pattern, you'll need to build a form that matches your curve to use when heating and drape forming the plexiglass. I'm pretty sure that process has been covered elsewhere in the forum so I won't get into it. I took my pattern to a local guy who has some expertise in plexiglass forming and he supplied the material and formed them for a reasonable cost.
Once you've got the formed plexiglass, you then start laying out the frame pattern using paper as shown below. You have to make separate patterns for the inside and outside since the thickness of the windshield changes the radius.
To reinforce the frame, I formed a length of 3/16" aluminum rod to match the contour of the back edge, then made my frame pieces long enough to extend around the aluminum rod and meet on the centerline of the back edge. You can also use aluminum tubing. Tubing is easier to weld to, but doesn't offer as much reinforcement. It's hard to make out the picture of the rod, but trust me it's in there.
Use a soft hammer to start forming the frame pieces around the rod.

Continue working the sides around to the centerline of the rod. Once it's formed, start tack welding. You've got to go easy at this point to keep from messing up your plexiglass. Keep your air nozzle handy to cool the tack as soon as it's finished. You will get a little bit of distortion right at the edge of windshield, but it's under the frame where you'll never see it.
After it's sufficiently tack welded, remove the clecos and remove the frame.
Finish welding it, but again take it easy and work small sections at time, otherwise it'll warp. You're almost home at this point. Now start cleaning up and dressing the welds. Whatever tools you use to do this, do yourself a favor and become familiar with wax. It'll lubricate your cutting/grinding tools and keep them from getting loaded up with aluminum chips. As you dress out the frame, you'll likely have some pinholes and other imperfections to deal with. Just add a little weld as necessary until you're satisfied with it.
Now you're ready to add the bottom/mounting flange. Again something that's been covered elsewhere. Polish it, Paint it, just get it installed and get the airplane flying......
Mark

Thank you for posting Mark, that is a huge help...

Neat job. Info. Some one on the forum has made cardboard patterns of a Stearman type windscreen and has made this pattern available to all who ask. I used his pattern and it worked very well.

Michael
N9648B

Michael,
Is there a chance you might be able to share the pattern with everyone, maybe load it on to the files section?
Amit.

mmcgrew wrote:Neat job. Info. Some one on the forum has made cardboard patterns of a Stearman type windscreen and has made this pattern available to all who ask. I used his pattern and it worked very well.

Michael
N9648B

I will need to find it??

Michael
N9648B

I just recalled - I mailed it on to another member. IS there any way to search old post?

Michael
N9648B