I have been doing some work on a Howard lately. One of my projects is the wheel pants. Some tooling was made years ago the hydroform the halves using water pressure. Kent White has a DVD about this process.
The tooling was designed from the factory wheel pant drawings but the parts came out a bit different, likely due to the tool, as massive as it was, distorting under the pressure during forming. Since we aren't going to make new tooling to produce more accurate parts I'll just have to use what we have.
While taking some photos to document my work I thought to post some of them here. I did post about the fixture design and build in Cameron's wheel pant thread. The basic steps after the fixture is complete are;
1) Trim the halves to remove the flanges and waste material from the forming process.
2) Locate the centerlines and axle hole.
3) Roughly fit the inboard half around the gear leg.
4) Locate the mounting holes in the inboard half.
5) Add doublers to the mounting points and rivet in place.
5a) Create access panel for servicing the tire pressure.
5b) Create inboard cover plate for area under the gear leg.
6) Join the halves and tack weld.
7) Finish weld and dress/hammer the welds flat.
8) Finish tire cut-out.
9) Create bulkhead for fitting aft of the tire (there's no forward bulkhead) and rivet in place.
10) Repair/re-fit/modify the intersection fairing to fit the new wheel pant.
11) Repeat for other wheel pant....
Outboard doublers. The axle nut is a temporary plastic one. Nutplates for the access cover instead of rivnuts which the Howard factory used a lot.
There's an angle between the end of the axle nut and the wheel pant surface of about 5°. I made a little doubler/wedge to make up the difference and it rivets in place. Without this wedge tightening the bolt would distort the wheel pant local to the axle. It was a PITA to make but it does what it needs to and was easier than creating an angled bump in the wheel pant.
Cover plate and angled (plastic, for now) washer. I flush riveted the doublers because the rivet pattern is much different than what the original parts had. The originals had steel straps for doublers that ran up and over the top of the pant to create a hard point you could stand on to reach the step tube on the gear leg. Since the only reasons to use that step are to check the oil and wipe the windshield we decided to put a 'NO STEP" sign on the top of the pant and use a step ladder instead. Howard used domed rivets everywhere on the wheel pant but I didn't want to do that and highlight the differences between this wheel pant and an original one so the rivets will be hidden.
A view of the inboard half from the inside. The clearance has to be large enough to allow you to lift the pant pretty much straight up. Our slightly different shape didn't help any. We're also fitting modern brakes and the caliper sticks out which required an even larger cut-out. Due to the size of the cut-out the inboard cover plate will also serve as a bracket to hold the pant to the gear leg.
The caliper is mounted with spacers to simulate its position when the pads are worn down to the metal -- the worse case for clearance to the wheel pant.
The caliper sticks out pretty far!
This will make the cover plate a challenge. The rivets on the inboard half are also going to be hidden.
The forward mount on the gear leg is in a good spot. The aft one not so much. Another challenge....
I started at the forward edge with a piece of .063" aluminum that was originally a jon boat bench seat. I trimmed the forward edge to fit (roughly) the cut-out's shape and used the English wheel to shape the panel similar to the metal that was cut out for clearance. I started the with the caliper removed and put it in place once I got the panel shaped and clecoed to the doubler on the forward edge. This was just going to be a test panel since I figured the first attempt or three would be scrapped. Takes the pressure off when it's only a test part, right? I'll use 'better' material for the real part.......
I put the caliper in place and noted where it touched the cover plate. I used doming dies in my CP planishing hammer and a large steel hammer with a nice radius and a rubber mat under the part to raise the area near the caliper until I had some clearance. Then I smoothed it out to blend into the original shape mainly using the English wheel and worked my way aft....
About the time I got half way back shaping this panel it started to look like a keeper. I have only one cleco holding the forward edge of the cover panel in place in this view. The panel lies nicely against the wheel pant all by itself. Starting to feel lucky here.....
The cover plate fully fitted except,,,,
Except for the bottom edge which will be done when the tire clearance cut-out is done. Not sure yet exactly what that will look like.
A view of the aft end. There's a small doubler on the cover plate to help transfer loads from the fastener into the panel. The aft inboard mounting bolt actually attaches to the cover plate and the cover plate attaches with four #10 screws to the aft end of the pant.
It's a little hard to see in the photos but the aft end has about a 1/2" jog just aft of the bracket on the gear leg. Of course it's not just a simple jog, the panel has a compound curve over its entire length so the jog is a compound curve too.
More to follow -- if anyone cares to see more.........
The tooling was designed from the factory wheel pant drawings but the parts came out a bit different, likely due to the tool, as massive as it was, distorting under the pressure during forming. Since we aren't going to make new tooling to produce more accurate parts I'll just have to use what we have.
While taking some photos to document my work I thought to post some of them here. I did post about the fixture design and build in Cameron's wheel pant thread. The basic steps after the fixture is complete are;
1) Trim the halves to remove the flanges and waste material from the forming process.
2) Locate the centerlines and axle hole.
3) Roughly fit the inboard half around the gear leg.
4) Locate the mounting holes in the inboard half.
5) Add doublers to the mounting points and rivet in place.
5a) Create access panel for servicing the tire pressure.
5b) Create inboard cover plate for area under the gear leg.
6) Join the halves and tack weld.
7) Finish weld and dress/hammer the welds flat.
8) Finish tire cut-out.
9) Create bulkhead for fitting aft of the tire (there's no forward bulkhead) and rivet in place.
10) Repair/re-fit/modify the intersection fairing to fit the new wheel pant.
11) Repeat for other wheel pant....
Outboard doublers. The axle nut is a temporary plastic one. Nutplates for the access cover instead of rivnuts which the Howard factory used a lot.
There's an angle between the end of the axle nut and the wheel pant surface of about 5°. I made a little doubler/wedge to make up the difference and it rivets in place. Without this wedge tightening the bolt would distort the wheel pant local to the axle. It was a PITA to make but it does what it needs to and was easier than creating an angled bump in the wheel pant.
Cover plate and angled (plastic, for now) washer. I flush riveted the doublers because the rivet pattern is much different than what the original parts had. The originals had steel straps for doublers that ran up and over the top of the pant to create a hard point you could stand on to reach the step tube on the gear leg. Since the only reasons to use that step are to check the oil and wipe the windshield we decided to put a 'NO STEP" sign on the top of the pant and use a step ladder instead. Howard used domed rivets everywhere on the wheel pant but I didn't want to do that and highlight the differences between this wheel pant and an original one so the rivets will be hidden.
A view of the inboard half from the inside. The clearance has to be large enough to allow you to lift the pant pretty much straight up. Our slightly different shape didn't help any. We're also fitting modern brakes and the caliper sticks out which required an even larger cut-out. Due to the size of the cut-out the inboard cover plate will also serve as a bracket to hold the pant to the gear leg.
The caliper is mounted with spacers to simulate its position when the pads are worn down to the metal -- the worse case for clearance to the wheel pant.
The caliper sticks out pretty far!
This will make the cover plate a challenge. The rivets on the inboard half are also going to be hidden.
The forward mount on the gear leg is in a good spot. The aft one not so much. Another challenge....
I started at the forward edge with a piece of .063" aluminum that was originally a jon boat bench seat. I trimmed the forward edge to fit (roughly) the cut-out's shape and used the English wheel to shape the panel similar to the metal that was cut out for clearance. I started the with the caliper removed and put it in place once I got the panel shaped and clecoed to the doubler on the forward edge. This was just going to be a test panel since I figured the first attempt or three would be scrapped. Takes the pressure off when it's only a test part, right? I'll use 'better' material for the real part.......
I put the caliper in place and noted where it touched the cover plate. I used doming dies in my CP planishing hammer and a large steel hammer with a nice radius and a rubber mat under the part to raise the area near the caliper until I had some clearance. Then I smoothed it out to blend into the original shape mainly using the English wheel and worked my way aft....
About the time I got half way back shaping this panel it started to look like a keeper. I have only one cleco holding the forward edge of the cover panel in place in this view. The panel lies nicely against the wheel pant all by itself. Starting to feel lucky here.....
The cover plate fully fitted except,,,,
Except for the bottom edge which will be done when the tire clearance cut-out is done. Not sure yet exactly what that will look like.
A view of the aft end. There's a small doubler on the cover plate to help transfer loads from the fastener into the panel. The aft inboard mounting bolt actually attaches to the cover plate and the cover plate attaches with four #10 screws to the aft end of the pant.
It's a little hard to see in the photos but the aft end has about a 1/2" jog just aft of the bracket on the gear leg. Of course it's not just a simple jog, the panel has a compound curve over its entire length so the jog is a compound curve too.
More to follow -- if anyone cares to see more.........
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