Sunday, November 29, 2009

A Little Slower - But Still Working

Welcome Back. We hope everyone enjoyed a Happy Thanksgiving this year. It's been a little bit slower paced around here lately, but we've still been working.
In this update:

1. Sheet Metal Brake Shoe
2. CAD Modeling
3. New Rotary Phase Converter Motor Stand
4. Plasma Torch Air
5. The Great Wall of Prowler

1. Sheet Metal Brake Shoe - In preparation to start bending a lot of sheet metal, we needed to modify our sheet metal brake to bend our aluminum with a radius. Standard sheet metal brakes come with fingers or shoes that will bend very sharp corners. Aluminum cannot be bent that sharply or it will crack between the metal grains. Most bends for Prowler Parts need 1/8" radius bends. So we needed to put the Bridgeport to use and make a shoe with a 1/8th" radius.

Now making hundreds of radius bends will be fast and easy with the modified brake. Should help speed up production. This covers the parts up to 4 feet. We've got another solution for parts over that length. Here's what the test piece looked like.

2. CAD Modeling - We've been using our CAD software to begin systematically modeling all of the parts and patterns for the Prowler. We learned to use the software while modeling a few of the parts (e.g. Tailwheel Strut) we've already mentioned in previous blog posts. But now we've begun to model all the parts in ernest. In the past two weeks we've completed the modeling of all the Vertical Stabilizer parts and the Horizontal Stabilizer parts. We're now starting on the parts for the center section of the main wing spar. BobCAD-CAM Ver. 23 was well worth the cost. Here's a sample of the software while modeling the Horz. Stab. skin.

3. New Rotary Phase Converter Motor Stand - While spending hours machining out the radius-ed shoe for the sheet metal brake, it became apparent that having the motor of the rotary phase converter mounted to a shelf on the wall behind the mill was not the best solution. The motor vibration was transmitted into the wall and amplified by the wall resonance. So, we used another of our new shop tools (MIG welder) to weld up a new motor stand that mounts to the concrete floor. It turned out great and the motor noise is substantially reduced.

4. Plasma Torch Air - We really need to get the plasma torch going. We're getting to the point where we really need to start cutting a lot of parts and we want to be able to use the plasma setup to do this - just like we will eventually be doing for production. We recently installed a new computer and the system is essentially set-up and tested. Here's a movie of the system cutting out a sample part we created (without the torch on):

The torch has tested fine as well, however, the weak link in the system is compressed air. Our air compressor did not have the capacity to keep up with the air required for the torch. In addition, the air cleaning/drying system we set up previously was not going to be adequate.

To solve the air supply problem we purchased a new (used) air compressor. Plans are in progress to find an acceptable to place to set up the air compressor outside of the shop. This will keep the noise down and make more room inside the shop. It will, unfortunately, require plumbing electrical out to the compressor and plumbing the air into the current manifold set up we have. Should be couple day project. More to follow.

To dry the air we purchased a new refrigerated air dryer and the torch cart has been modified to hold it. We still have to plumb the filter and the misc hookups. This project will be at the top of the list in the coming weeks.

5. The Great Wall of Prowler - Since the Prowler (West) shop was built we've been wanting to widen the driveway around the shop and add room to get in-and-out of the south garage door. We recently got access to a lot of broken concrete and fill from a job site. We transported it all to the shop and have begun to build a retaining wall around the front of the shop. It will give a lot more space for driveway and should help improve the look of the property. Unfortunately not everything can be directly related to building Prowlers!

That's it for this update. We'll update again when there is more to report. Thanks for stopping by.