Some of you remember that I had a close encounter with some birds a few months ago, and that I was changing the bubble windshield to a thicker flat wrap. I figured some of you would like to see the highlights of the process, and since I can't figure out exactly which topic this fits into, it's here. One thing that may keep it here is that despite the seemingly substantial aerodynamic cleanup (beyond the rakish new windshield), I have not seen any speed increase. Much attention to detail was spent on the windscreen to canopy transition as well as how the canopy skirt tucks in behind a new fairing. Compared to what it was, these areas are very fine - yet (seemingly) to no avail.
Oh well, at least it looks cool!
This hole caused by a few inconsiderate birds got the process rolling...
Since this airplane had two prior windshields, I welded up the roll bar to seal the holes.
I used a straight edge to see where the line drawn from the canopy bubble would fall on the boot cowl. On this canopy, a straight line tangent to the canopy radius falls on the boot cowl 24 inches from the front of the roll bar. Rough cardboard template cut to fit
Since the "E-AB" category is all about education and learning new things, I decided I'd learn how to make a heat formed windshield. I made a buck using the roll bar as a loose pattern.
Buck was skinned with thin ply, finished with filler and covered with felt.
Since I couldn't find an oven big enough, I made my own out of plywood. I upped the thickness of the plexi to .250"
Rough cut the windscreen using the cardboard template. There is a lot of trimming and fitting after this step!
With the base of the windscreen this far forward, the baggage door need to be notched and fixed structure added to the boot cowl. I decided to make things difficult by making a cut following the windscreen radius.
I had to de-skin the door and move some structure around inside.
With my decision to follow the windshield , I set myself up for a compound curve on some of the edge structure. Fortunately, my shrinker/stretcher made short work of that.
It's serviceable... I'm still kicking around the idea of doing a new one in composite with a hidden release latch.
While I was at it I decided to fix the area around the skirt. I had to do some surgery and pull in the canopy frame tight to the fuselage. These fairings smooth things out big time. No more gaps!
New shape windshield means new glareshield cover. This is black canvas with pockets for charts and pens sewn on. Also has a big strip of velcro for any of the antennas needed in the future. The 430 antenna is permanent, of course.
With such a rakish angle on the windshield, the transition needs to lay down pretty well against the boot cowl. There is only one mechanical attachment on the boot, and it is a small clip right on centerline. It is buried under the fiberglass. The clip was there mainly to keep things from moving around while the tank sealant and glass cured.
I still have a bunch of bodywork to go before it's ready for final paint, but it's plenty good enough for the time being. All gaps are very tight, and I was even able to incorporate a nice foam seal. The canopy closes like a bank vault.
So overall it's been an interesting modification. It took just under 2 months of weekends to get it flying again. Certainly, if I had purchased the windscreen I would have saved myself a ton of time, but E-AB's are for education and experience and I already know how to write a check...
The modification added 4 pounds to the airplane and it is noticeably quieter. The drumming of the prop is the biggest reduction. And, yes, I have done some limited speed testing to see if it picked up anything... I have not noticed any increase in speed both flat out, nor in long distance cross country cruise. Of course, I had hoped that all my cleanup would pay off in speed, but I did the modification for increased birdstrike protection. While I am confident that I have achieved that goal, I'm not about to test it.
Oh well, at least it looks cool!
This hole caused by a few inconsiderate birds got the process rolling...
Since this airplane had two prior windshields, I welded up the roll bar to seal the holes.
I used a straight edge to see where the line drawn from the canopy bubble would fall on the boot cowl. On this canopy, a straight line tangent to the canopy radius falls on the boot cowl 24 inches from the front of the roll bar. Rough cardboard template cut to fit
Since the "E-AB" category is all about education and learning new things, I decided I'd learn how to make a heat formed windshield. I made a buck using the roll bar as a loose pattern.
Buck was skinned with thin ply, finished with filler and covered with felt.
Since I couldn't find an oven big enough, I made my own out of plywood. I upped the thickness of the plexi to .250"
Rough cut the windscreen using the cardboard template. There is a lot of trimming and fitting after this step!
With the base of the windscreen this far forward, the baggage door need to be notched and fixed structure added to the boot cowl. I decided to make things difficult by making a cut following the windscreen radius.
I had to de-skin the door and move some structure around inside.
With my decision to follow the windshield , I set myself up for a compound curve on some of the edge structure. Fortunately, my shrinker/stretcher made short work of that.
It's serviceable... I'm still kicking around the idea of doing a new one in composite with a hidden release latch.
While I was at it I decided to fix the area around the skirt. I had to do some surgery and pull in the canopy frame tight to the fuselage. These fairings smooth things out big time. No more gaps!
New shape windshield means new glareshield cover. This is black canvas with pockets for charts and pens sewn on. Also has a big strip of velcro for any of the antennas needed in the future. The 430 antenna is permanent, of course.
With such a rakish angle on the windshield, the transition needs to lay down pretty well against the boot cowl. There is only one mechanical attachment on the boot, and it is a small clip right on centerline. It is buried under the fiberglass. The clip was there mainly to keep things from moving around while the tank sealant and glass cured.
I still have a bunch of bodywork to go before it's ready for final paint, but it's plenty good enough for the time being. All gaps are very tight, and I was even able to incorporate a nice foam seal. The canopy closes like a bank vault.
So overall it's been an interesting modification. It took just under 2 months of weekends to get it flying again. Certainly, if I had purchased the windscreen I would have saved myself a ton of time, but E-AB's are for education and experience and I already know how to write a check...
The modification added 4 pounds to the airplane and it is noticeably quieter. The drumming of the prop is the biggest reduction. And, yes, I have done some limited speed testing to see if it picked up anything... I have not noticed any increase in speed both flat out, nor in long distance cross country cruise. Of course, I had hoped that all my cleanup would pay off in speed, but I did the modification for increased birdstrike protection. While I am confident that I have achieved that goal, I'm not about to test it.
