Headed Into The Good Ole Summertime!

Welcome back and thanks for stopping to check in on Prowler Aviation.  I've got a few new items to update and some updates on progress of older topics.


1.  100Ton Press Repairs
2.  Work On "Kit #18"
3.  Parts For Kit #6
4.  Builder Updates
4.A.  Ray
4. B. Bryan
4.C.  Francis & Robert
5.  Prowler Sheet Metal Shear
6.  Lathe Enclosure
7.  New Door On Sandblast Cabinet
8.  Generator Test
9.  Yoder Power Hammer Progress
10. Next Moves


1.  100Ton Press Repairs -  During the initial tests in using the press to form parts, I discovered that the process was essentially working (covered this in the previous post).  The bad news was, I had bent the press's upper H frame that holds the "lid" to the box that contains the rubber when pressing a part.  With the center of the lid humped up almost 3/16" - any attempts to bend a long part might cause the part to not be formed over the die completely.  So, I needed to repair the press and then "beef it up" so that it would not continue to bend while forming parts.  This was going to be a perfect project for dad and I to work on together during my parents annual spring visit to see the grandkids.
The first step was to remove everything off of the top of the press and then remove the lid and spacers from the upper H frame.  The lid and spacers are welded together as one unit and it was easily straightened in the press by flipping it over and putting shims in the proper places.
Next, we headed off to the local surplus steel place to find some "beef."  We picked out two pieces of 3/4" thick x 6" wide steel flat bar to scab onto the inside of the upper H frame angles.  We decided to forgo trying to straighten the two angle irons and just leave them bent.  It would have been a lot of extra work and might have introduced more alignment issues when trying to put it all back together.  Here's a pic:

The reality is that the frames can be bent without any issue as long as the lid of the rubber box is straight.  Once we had the H frames beefed up and the lid straightened we began the process of putting it all back together. You can see the two end spacers are mostly tight to the H frame, but the center has a pretty large gap.  Before we finished tightening the bolts up, I measured for shims and placed shims to take up this extra space in the center.  Here's a pic of the spacers and lid being bolted back onto the H frames:

 And, another showing that the lid is straight:

 With the top of the press repaired, we decided that the forces of the pressing operation might now cause the bottom H frame to bend.  So, we added 5/8"gussets in the corners of the thick steel ram block that sits on the lower H frame plates.  Here's a pic:

 With the lower H frame beefed up, it was just a matter of putting all the stuff back on the press, put some wood in the box and take it for a test run.  Everything checked out.  Here's a pic of the press put back together after the ops tests:

With the press back together, it's time to cut a new set of dies and try to press some more parts.  However, I have one remaining problem - I need to find a 2-3" thick rubber pad that is about 65-70 durometer rubber.  I've researched this online and found a few places that I can purchase this rubber - problem is that it is kinda far outside the budget for this tool.  So, I'm looking around for a lower cost option.  I'll keep on cutting more dies while I search for some surplus rubber at auctions and surplus industrial places.  Hopefully, I will have something more to report on this by the end of summer. 

2.  Work On "Kit #18" -  The kit that I picked up just after the new year from Salinas, CA has been the focus of most of my attention lately.  I've added it to my "kit list" spreadsheet that I use to track all of the Prowler kits (owners, contact info, status, etc).  This kit has been given the serial number of "Kit #18."  I have been going thru each of the parts and inventorying everything and dividing them up into the respective sub-kit sections.  Also, while going thru all the parts (sub-kit by sub-kit), I have been going thru my old inventory from George to see if I have any of the needed missing parts.  If so, I'm adding it to the kit.  Then, where missing parts are fairly simple and easy to fabricate, I have been making many of these simpler parts.  Keep in mind, however, that these are hand-formed parts that I am making from the patterns that I got from George - just the way that he made them back in the day.
Here are some pics of the sub-kits bundled and setting around my office (no room left in the shop!).  This is fuselage parts and firewall on the right (over exposed by the sun):

 Here are the center wing framing components on the left and ailerons on the right:

 This is the outer wing ribs and fuel tank bulkheads:

 The flaps on the left and the rear spar components standing in the corner:

 The center section main spar and outboard wing spar parts:

Here are the vert stab and the horizontal stab:

These are leading edge skins on the left, more center sections spar parts lower center, torque box parts lower right, rudder parts and skins on left center and behind, elevator parts and skins in center and upper left:

 

Main landing gear struts and cockpit framing components on left:



At this point I have a pretty detailed list of what is included in the kit and that parts that still need to be fabricated.  Currently, I have offered this kit to someone that might be interested in it - in an "as is" condition.  If he decides to take the kit, I will be able to help him fabricate the missing parts as needed.  If he passes on this deal, I will probably continue to fabricate the missing parts and then offer the kit for sale in the future.  Stay tuned for more.

3.  Parts For Kit #6 -  Once Bryan got a chance to inventory the kit that he and I picked up just before Christmas, he sent me a list of parts that was missing.  Here's a pic of most of the parts that I fabricated to finish out this kit:

In order to fab the MLG follow-up door hinges I had to make a jig that would hold the hinge bushings precisely in place while they are welded to the angle flanges.  To do that, I welded pieces of 1-1/2" angle steel back-to-back onto a piece of 1/4" flat stock.  Then I used the manual Bridgeport mill to place two slots for the bushing to set in:

To weld the parts together, the angled flange sits in the slit formed by the two back-to-back angle iron pieces, and rests on top of two bushings placed in the slots machined into the base:

This keeps everything perfectly aligned while the bushings and flange are TIG welded together:

Here is the end result - two completed MLG upper follow-up door hinges:

4.  Builder Updates
4.A.  Ray Prowler Progress - Ray is in the process of going thru all of his airplane again, system by system, getting as many bugs and gottcha's taken care of as possible before his 1st flight.  Recently Ray was going over the tailwheel compartment and called to tell me that while he was working on his tailwheel, he noticed that as he moved the tailwheel slightly the MLG inner doors would move up/down a little.  After some investigation he concluded that the MLG inner door sequencing valves were bypassing hydraulic fluid when they should have been closed.  Here's a pic that shows the position of the sequence valve:

Ray took the valves out and determined that when George had made the valves, the seats had grooves in them that we allowing the balls to not seat properly. This was allowing fluid to bypass and move the gear doors up (potentially) before the gear was actually in the well.  It took Ray a few days and a couple of do-overs, but he finally got the valves rebuilt and installed.

The latest report from Ray is that he has found some fuel leaks in the wings.  It looks like he will have to remove the wings and slosh the tanks to get the drips stopped.  The good news is (in Ray's words):
"So far the design works, everything seemed to flow where it was supposed to go from the tank to the engine feed line.  I could fill the Aux tank from the leading edge tanks with no problems.  The check valves in the fuel feed lines do not seem to reduce the flow of fuel from the tanks, and the vent check valves at the wing tips prevent reverse flow when blowing air from the vacuum  cleaner into the tank.  When draining the tank from the drain fitting just past the fuel pump it will drain at about 5 min per gal from the forward tank by gravity alone.  The Aux tank can be emptied completely by pressurizing the Aux tank vent line and blowing the fuel out the drain fitting..  Aside from the pump thing and the one leak the fuel system design looks like it will get the job done."
Hopefully, the tank sealing will go well and that will take care of the fuel system issues.  Ray also indicated that he has a medical issue that will cause some of the Prowler work (and 1st flight) to move to the right for a while.  Here's another pic from Ray's airplane reveal of his new paint job earlier this year:

As he gets closer and closer to his 1st flight, I will pass along more of Ray's progress in future updates.

4. B. Bryan's Prowler Progress -  Bryan has been out on "medical" lately while he has had Lasik done on his eyes by the best doctor on the planet (in Europe).  Then, in an strange turn of events, he made it all the way back to the States after successful eye surgery - only to get injured while pushing his airport car out of it's parking spot to give it a jump start!  As Bryan states:
"We are back!  However, when I got to the crew lot after jump seating from STN  i had to push my car and ruptured all the tendons in my right foot. I am now confined to a wheel chair and can not walk. Dr. says 2 months in the chair to start."
Whoa!  Sorry to hear that Bryan.  That's a major bummer.  In a recent follow-up Bryan said:
"I have gotten through the high risk area with flying colors. No ill effects, infections or issues with wound healing. However... now with a hard cast bolted on I am still under the order to not use the foot for anything. Can't put any weight, walk, stand or dance on it. At best I can use my toes for limited tasks like touching the channel changer on the remote. So, another month of this and then I should start with some reasonable mobility.   I have the promise that when this is all over I will be as good as new!"
It's great to hear that the recovery is starting out well and that recovery should be 100%.  Bryan also reports that he's using this down time to clean up all of his Prowler documentation and begin writing his Aircraft Flight Manual (AFM).  I guess life is all about "making lemonade."

Well, before Bryan left to have his Lasik procedure done, he managed to go get a bunch of lumber and OSB sheathing and made crates for all of the Kit #6 parts that we recovered late last year.  By the looks of the pictures he sent me, he did an awesome job.  Here is Kit #6 in crates for shipping to a future buyer.  This is obviously the MLG:

This looks like the smaller formed aluminum parts:



This looks like the crate of longer and larger formed aluminum parts:

And, here are the 5 crates with nearly all of Kit #6 inside them:

Nicely done, Sir.  We will be advertising this kit (and possibly another) in a future blog update.  Stay tuned.

4.C.  Francis & Robert -  I have gotten a few emails from Francis in France with update pictures on their progress on the French Prowler.  In a previous blog I showed the MLG HCAB that Francis was welding up.  Here they are completed and painted:

 and:

Great job on these parts, Francis!  They look very, very nice.

Here are a couple of shots of their outboard wing spars after they have been alodined and cleco'ed together.

 And:

And:

According to my last email, they should now have the outboard wing spar riveting completed.  I should get another update soon.  I will share it when I do.

Francis and Robert are also doing some initial research on the engine that they have for their Prowler.  It is one of George's original Auto Aviation engines from the 1980's.  George had sold almost 30 of these auto conversion engines using the old Oldsmobile F-85 aluminum block engine (and his proprietary reduction gear and accessories gear drive).  I showed these to George a few weeks ago and he could not tell precisely which engine this was, or what airplane it went on after he sold it.  He did say that this was not one of his motor mounts.  Someone had must have had it made for another application.  Here are a few pix:

 

And:

And:

They are looking for documentation and information on rebuilding this F-85 engine.  I have some info on the reduction gears and accessories gear drive, but not much on the Olds F-85.  If anyone has any info to share, please forward it to me at the feedback link on our website:
http://www.prowleraviation.com/contact/contact.html

Excellent work guys!  You are progressing very quickly.  It looks great!  Francis, thank you for the frequent updates and information to share here on the Prowler Blog.

5.  Prowler Sheet Metal Shear -  Earlier this year I purchased a used Pexto 52" gap shear (actually got it when I picked up the partial kit in Salinas, CA).  Like most Prowler equipment I purchase, it needs a little TLC, but it should work fine.  This exact same shear is still available, brand new, from Roper Whitney for the cool sum of $16K.
http://www.roperwhitney.com/foot-squaring-shears.html
Obviously. being used, I didn't pay anything near that.  But, this is still a very valuable tool for cutting airplane parts, because it is a gap shear:

In the following pic, you can see the "gap" behind the shear blades.  This gap allows you cut a metal strip of up to 18" wide and as long as you want - because you can index the sheet from right to left and continue a cut.  So, you can cut a strip up to 20 feet long, if you want or need to.  That's a good thing when cutting 8 ft long outboard wing spar shear webs, or 8 ft long blanks for 2" C channels, etc.

This was originally designed and built as a "stomp" shear.  Someone has since converted this to a pneumatically operated shear.  While that may be desirable for fabricating some types of metal parts, the ability to have very accurate control of cutting lines for aircraft parts makes using the "stomp" shear more desirable to me.  So, I am considering trying to fabricate the missing treadle (you can see where the treadle attaches to the lower shaft in the 1st pic above and in the following pic) and convert this back to a stomp shear.  Here's a shot of the back side of the machine.  You can just see the top of one of the pneumatic cylinders on the lower right hand side:

So, this is another project that needs to get done at some point.  The first thing I need to do is to get this thing up on casters so that I can move it around the shop (it weighs 1800 lbs!) and make room when I need space.  More to follow.

6.  Lathe Enclosure - Years ago I took apart an large air handling/filter unit that had a 5hp 3phase motor in it that I wanted to scavenge for a rotary phase converter that I was building.  The guy that I got it from told me that he would only sell the motor if I took the entire enclosure with it.  Part of the filter housing was almost the perfect shape to make a back-splash guard for my lathe.  When dad was in the shop in April we finished making a few required mod's and painted the housing:

Then, we mounted it to the back of the lathe pan.  It only needed some slight modifications and it fit almost perfectly onto the back of the drip pan that I made for the lathe a long time ago.

One more small project off of the "to do list!"

7.  New Door On Sandblast Cabinet - One of the things I got from Chuck's hangar a few years ago was his old, small sandblast cabinet.  It's not too big, but really handy to clean up small parts.  And, it doesn't take up too much space in the shop.  But, the old top did not have a rail around the edges of the Plexiglas and the glass was old and the corners rolled up.  So, the top loading door/glass leaked dust out pretty bad.  Also, the florescent light was not working.  So, dad and I made up a new frame and mounted new glass for the new top loading door:

And, I bought a similar florescent fixture from Home Depot and modified it to fit into the existing enclosure and......there was light:

This should be a really handy tool to clean up parts in the future.

8.  Generator Progress & Test -  I got motivated this spring to try to get some of my many projects that have been "hanging fire" move into the "completed" category.  The back-up diesel generator was one of these.  This project has been waiting for me to solve how I was going to handle the alternator for the Kubota engine that runs this generator.  Like in most engine designs, the alternator is used to (obviously) charge the battery and it also serves as the belt tensioner of the one belt that drives the alternator and the coolant pump (off of the crankshaft).

Well, in this application I really didn't need an alternator.  During periods when the engine is not running, the battery can be topped off by a battery charger.  Also, as soon as this engine starts it automatically begins generating electricity from the 15kW generator attached to the crankshaft.  That can also be used to power a battery charger and replenish the battery charge.  So, I decided to fabricate an idler pulley that used the same mounting system as the alternator and use that to take the place of an alternator.  I started with a 1/2" steel plate in a triangular shape.  Then, I added the L shaped bracket to place over the original alternator hinge point on the engine case.  You can see it here:

Next, I machined down a shoulder bolt that would allow the pulley to ride up against the shoulder cut on the stud.  Then I drilled a body fit (close tolerance) hole into the 1/2" steel plate and pressed the stud into the plate.  A little weld on the back side of the plate (just barely visible below) is all that is needed to hold the pulley stud in place.  After bolting on the sliding tension arm (darker gray color part on bottom), the tensioner pulley was in place and the engine could finally be run for long periods.  Previously, I could only run the engine for short periods because the coolant pump was not powered.  Now, I could run the engine normally:

Then, I started the process or re-wiring the old instrument panel for the generator.  Here I am wiring up a series of 12V relays that turns on power to the instrument panel, powers the starter to start the engine, and powers the glow plugs and fuel pump.  Not the best pictures, but you get the idea that the wiring can get a little involved:

Here below, you can see the first couple of relays that I am working on in the center near the bottom.  You can also see the back of the instrument panel that came from an old Onan genset.  The instruments in this panel are: one AC voltmeter; two AC current meters (one for each side of the 220Vac); and a frequency meter (to sync the system to 60 Hz).  Then, for the engine there is an oil pressure gauge and a water temp gauge:

With the generator put back together to this stage, I was able to run the gen for longer test runs. All seemed to be working well.  Then, one day in April, the power went out for the best part of the day, and I was able to hook it all up to the 220volt system in the shop.  After disconnecting the property from PG&E, I back-fed the power to the whole property (shop, well, house, garage, etc.).  The engine and generator ran great for over 4 hours and kept everything powered! 

Now, the only remaining work on this system is to add two protection circuits.  I have to add a LOW oil pressure switch and HIGH water temp switch that will each activate the fuel shut-down relay in case of a failure of each.  This is the minimum requirement to protect a genset to keep the system safe in case of oil pressure failure or coolant failure.  I hope to get that done sometime this summer.

9.  Yoder Power Hammer Progress - You might recall that I was helping a buddy do the CAD work to build a Yoder inspired power hammer of his own design.  A few months ago he called to see if I wanted to go up to the shop that is building this machine and see the progress on it.  So we met for lunch and then went to see the machine.  Here is a picture of the gang (Max's son Koby on left, Max, and Keith in front) inspecting the progress:

 The base is 4ft x 4ft and made from 1" solid steel plate.  Here is Max checking the inside welds:

This is the top looking down the length of the tower.  It is a 15" x 15" column made from 1" plate steel shaped into to two "C" channels and then welded together.  Then the stiffeners were added down the middle to transfer some of the stresses from the upper and lower arms on the one side of the column to the other side of the column making the whole machine stronger:

Here's the lower arm attached to the main tower:

These are the side brace pads that hold one end of a large steel rod that braces the lower arms to either side:

For reference, here is what a real Yoder looks like:

It's nice to see the work that I did to make the CAD drawings has assisted in turning this project into an actual machine that will help Max in his profession.  When the machine is closer to finished, I'll update again.

10.  Next Moves - Here's a punch list of items to get done in the shop arranged from highest priority on down:
1. Find a suitable block of rubber for the Rib Smasher Press
2. Cut the dies for the new style tip ribs for the 1st New Prowler production airplane;
3. Form the tip ribs and fit them onto my wing spar and wing jig;
4. If these new tip ribs turn out OK , then make dies and press nose ribs for Francis and Robert;
5. Get the diesel genset finished with the protection systems and get it out of the shop;
6. Get the Pexto shear on casters and get it working for cutting airplane parts;
7.  Find new homes for 1 (or possibly 2) second had kits that Bryan and I have.
8.  Squeeze in time for a week at AirVenture ;-)

Thanks for stopping by to check on the progress here at the New Prowler Aviation.  I know things seem to move at a glacial pace around here at times.  But, I'm always working on something related to Prowler (nearly every single day) and I am trying to support the current builders in any way that I can or is needed.  Please send feedback if you have any thoughts, concerns or suggestions. 
http://www.prowleraviation.com/contact/contact.html
Have a great summer!

Off To An Interesting Start in 2014

Hello Again,

Well, every time I sit down to type up some narratives about what's going on here, something comes up that needs attention and I end up having to put off the blog update.  Unfortunately, it happens a lot, much more than I like.  But, the reality is that, the blog updates are the easiest thing for me to "move to the right" and find time to give attention to emergent issues that come up.  The downside to that is that more and more info gathers up for each blog update  until they get to be very large updates; also something I don't particularly like.  Anyway, I got a break in the action for a few days and I'm gonna "git'er done"!

Items for this update:
1.   Ray's Aircraft Paint
2.   Formed First Part Using The 100Ton Rib Smasher
3.   French Prowler Progress
4.   Bryan's New MLG HCAB Becomes Standard Prowler Equipment
5.   An Update From Bryan
6.   News On The Original Prowler
7.   Another Kit Rescued From The Recycling Bin
8.   Aircraft Available


1.   Ray's Aircraft Paint -  I received a CD in the mail recently from Ray.  It was full of pictures from a photo shoot of his airplane that he and his painter (Andy) did one early morning.  Doing the shoot using early morning light gives a diffused light and not as much glare.  Ray did an amazing amount of research to find an authentic paint scheme and authentic (as close as possible) paint colors to WWII period military aircraft.  The results of both of these jobs combined is amazing!  The paint job was extraordinary (nice job Andy).  Enjoy these:

Ray tells me that the next steps are extended engine runs (testing) and getting some flying time again (dual in a taildragger).  I'll keep you posted. 

Beautiful aircraft, Ray!  You have done one top notch, outstanding job building your airplane!


2.   Formed First Part Using The 100Ton Rib Smasher - In the last blog update I outlined how I made the die in preparation for making my first Prowler part using the pseudo hydroforming process.  After machining the die, the next step was to CAM out and cut blanks out of 2024-T3 to use make the parts.  Here they are after cutting:

You can't see it in the picture, but there are 4 tooling holes that were cut with the router that match the 4 tooling holes in the die.  Here are the blank and the die side-by-side:

Next, the blank was placed on the die and the tooling pins placed in the tooling holes to hold the blank in place while the part is being formed:

Now the die and blank are placed in the bottom of the press box:

 Next add rubber and squeeze:

 This is the result:

 Here is the newly formed part removed from the die:

 Here is the formed part on the under side:

 And the top side:

Ultimately, it proves that the process does work - in theory.  However, the part is not completely formed in a few areas.  The sides are not yet at perfect 90 degree angles to the face of the part.  Also, the flange around the hole is not completely formed. 

I have been researching what I can do to make this process work a little better.  I think I've found several things that will need tweaking: 1) the rubber that I found to use is likely too soft and not thick enough; 2) the total amount of rubber packed into the box is too little;  3) The size of the pocket in the top of the die to make the hole flange was not quite large enough; and 4) the press may be too small for this size of part.  Yeah, believe it or not, 100 tons may not be enough force to form this roughly 10" x 10" part!  And, this part was made from only a .032" stock.  A part from .040" will be even harder to form.

The other problem is, even though 100 tons may not have been enough force to form the part, it was enough force to bend the press - and not in a good way.  Check the "new" shape of the upper H frame of the press:

The vertical bent looking part on the far end of the press is the handle for the manual pump and is not a problem.  The problem is the gentle curve of the upper frame, and subsequently the "lid" of the press box.  The big problem with this is that if I try to form a long part and the box is stuffed with rubber, it will form the part (press harder) on the ends than it will in the middle.  So, the long parts won't come out fully formed near the middle of the part.  So, the press needs to be cut apart and I have to beef up the steel in the upper H arms.  This fix is on the agenda while "Pop is in the shop" next week.

3.   French Prowler Progress -  Francis and Robert have been doing a great job and making really good progress on their Prowler.  Here is an excerpt of a recent email from them:
Hi Todd,
First we wish you an happy new year.
We would like to keep you updated on how things are going on here.
Main spar, wings spar are re-drilled and we have treated the main spar in alodine just before Christmas (att. pics.).
We hope to start riveting on January and then i will send you more pictures for your blog.
All the best for you and for your family
Francis and Robert

Here are the associated pix:

Then, later on I got an update showing the spar riveted together and installed in the wing jig.  Check these out:

Looks great.  Excellent progress gents.  Now that they have their spar riveted together and are getting ready to start "decorating it" - Francis wrote to tell me that they did not get the MLG Hydraulic Cylinder Attach Brackets (HCAB) in their kit.  After presenting them with options, they chose to have HCAB fabricated the same as Bryan's new design.  This discussion continues in the next topic, below.

Great progress on your airplane fellas.  Please keep the pix and info coming!

4.   Bryan's New MLG HCAB Design Becomes Standard Prowler Equipment -  A few years ago, Bryan came up with a great design for the Main Landing Gear Hydraulic Cylinder Attach Brackets (MLG HCAB) that performs the same main function (to hold the inboard dead end of the MLG hydraulic actuating cylinders), but it also incorporates the lower portion of the negative G mod that is required.  Since Francis and Robert wanted a set for their aircraft, and I need a set for my airplane and there are two kits available that can use this new design - I decided that I should fire up the CNC machines and get 4 sets of them fabricated.

As with all things CNC, the first step is to have a drawing.  Then, you turn the drawings into tool paths (which is the CAM function).  However, before you can even finalize your drawings, you need to use some imagination and decide how you will fixture (hold) your parts while you machine them.  Sometimes, the drawings (and eventually the tools paths) change depending on how you can best fixture your parts.  So, you have to get a bit ingenious occasionally as to how you can best accomplish this.

In the case of the parts for the MLG HCAB's, I decided to use existing holes in two of the parts as tooling holes to fixture the part and in the other parts just pick some out of the way spots to put some tooling holes.  Then, I added the correct hole drilling operations to the original CAD drawings to place the tooling holes correctly.

With the decision made of how to fixture the parts, the next obvious step is to build the fixture.  Here is the plate I made for this set of parts.  I have bolts into T-nuts holding it to the mill table:

 Here's the same fixture with the clamps (bolts with washers or steel strip) in place over the raw stock patterns that I create while I am "testing" the process and making the first practice pieces:

With a little more imagination, I was able use the same fixture plate to hold all of the parts for this assembly.  Here is one of the other main parts with clamps in place over the raw stock patterns:

 And here is the last main part:

 Here are two raw stock patterns laid out on a piece of stock.  I use these patterns to trace the parts onto the raw stock to try to get the best use of the material (least waste).  This process is called "nesting" parts.  I have found that with the 4130 steel parts, the closer I can get the stock cut to the final shape of the part (without taking off too much) - it makes the milling process go much faster and easier.

Here are some of the rough cut raw stock before drilling the tooling holes and mounting them in the mill for machining:

 If I get the raw stock pieces cut out fairly closely, I determined that I could make 4 of each piece at one time by simply stacking them.  The clamps worked great to hold the material stack in place for machining:

 Here is a completed stack. The aluminum piece you see on the bottom is a soft spacer placed under the stack of stock to allow for the tooling (cutting endmill) to stick out below the bottom of the bottom piece in the stack, but not cut into the steel of the fixture.  I just decided to use this technique as it is pretty simple and I had the extra .040" aluminum around.  Another technique is to use an oversized endmill to cut a "moat" into the fixture plate one time.  Then, when cutting the parts, the end of the cutting tool you use for that rides around in the air of the "moat" and doesn't actually cut into the steel of the fixture plate.  BTW - these parts are made from 0.100" thick 4130 Chromoly steel:

Here is the stack of rough cut raw stock of one of the other parts clamped in the mill before the final machining.  On this part I picked two arbitrary and out-of-the-way places to put the two tooling holes:

 And, finally, the stack of machined parts that the MLG HCAB's will be made from:

Now, it was onto some forming of these pieces to get them ready for final assembly.  In the end these parts will be TIG welded together to form one complete part.  Here is the CAD drawing of what those parts look like:

After bending a few of these parts in the sheet metal brake and putting a 3/4" spacer between them and a 1/4" bolt through the tooling holes - this is what one of the real things looks like:

 

The "web" piece you see with the larger hole in it and the small triangular gusset piece were just fabricated from small scraps of the left-over steel plate.  These were simple straight parts that didn't require CNC fabrication and I essentially made them by hand from the scrap pieces.

You might also notice that the blue CAD version of these parts (above) has a large lightening hole in the vertical parts and the fabricated pieces do not.  That is because I needed/wanted to use these holes to double as tooling holes.  Same thing for the upper hole which is used to hold the inboard end of the hydraulic cylinder.  Since the bolt for the hydraulic cylinder is a 5/16" bolt and since most hole saws use a 1/4" pilot drill - I chose to make these tooling holes 1/4" holes.  That way, 1/4" bolts can be used to fixture the stock for machining and to assemble the parts for welding.  Then the upper hole gets enlarged to 5/16" for the cylinder bolts.  And, the lower hole can have a hole saw run into the lower 1/4" hole to create the lightening hole - once the part is welded and completely fabricated.

Here are Francis and Roberts MLG HCABs tack welded together:

I shipped these parts to France without welding them since Francis is an aircraft welder and could do the welding for their parts.  Also, it made for a smaller package to ship them.  I still have not gotten the other 3 sets welded up yet, but it is on the to-do list.  More to follow.

5.  An Update from Bryan -Bryan has been making a lot of progress on his Prowler D aircraft (the D is for diesel).  However, he is at the point in his building that the progress is very transparent to the casual observer.  This is because it is a lot of wiring, plumbing, and panel work that takes a lot of time, but does not add a lot of visible change to the airplane.  Here is a shot of the overall airplane currently:

A recent mod to his elevator hinges. Elevator bearing mod with new bracket attached and old bracket removed:

Bearing placement on elevator.

Inst. panel mock up minus the GTN 750 which goes below the Dynon unit and that is it.

Looks awesome, Bryan.  The changes may not seem that obvious to you because you see your airplane all the time.  But, I/we can see the changes between updates.  Very nice work.  Very clean looking panel!

6.  News On The Original Prowler - I was contacted recently by Curt, the owner of the original Prowler.  His airplane was the original aircraft that George built to house his Auto Aviation engine design. 

Many people don't know it, but George started out creating the Auto Aviation company and designing a converted auto engine FWF system to power experimental aircraft.  His first F85 Oldsmobile engines were installed on a Steen Skybolt and I believe one other airplane (not sure which).  It wasn't until later that George started looking for a sleeker airframe to put  this FWF engine design on and couldn't find the right one.  For one reason or another all of the available experimental airframes of that era weren't a good fit.  So, George decided to design and build his own airframe to provide a fitting match to his FWF package.  Thus, the Prowler was born.

So, Curt contacted me to let me know that the airplane needs to have the engine rebuilt from a cam shaft failure - that I think happened a while back.  Here is the most recent photo that I have of that airplane:

Anyway, Curt is starting to plan the rebuild of his engine, accessory gear case and PSRU.  Thanks for contacting me, Curt.  I look forward to providing any support and assistance that I can to help you get your Prowler flying again!

7.   Another Kit Rescued From The Recycling Bin - Late last year I was contacted by Perry, the son of Mike Dodd.  Mike was a very good friend of Chuck Westcott and was also a very avid Prowler enthusiast.  So much so, that being an engineering draftsman, he had created drawings of most of the Prowler airplane from information he gathered from various sources.  He also built much of his own Prowler "kit" over the years.  Mike was also a "collector" of all thing aviation and had a shop full of "stuff".  Sadly, within a year of Chuck's accident, Mike passed away from cancer. 

In an effort to save Mike's (and Perry's) home in Salinas, CA from foreclosure, Perry decided to sell off all of the airplane "stuff" in Mike's shop to keep paying the mortgage while he fixed the house up and got it ready to sell.  That's when someone put me in contact with Perry and we discussed what Prowler items he had available.  Eventually, this past January, I took the truck and trailer down to meet Perry and purchased a lot of Prowler and airplane building "stuff" from Perry.  Here's what it looked like while packing it all in at Perry's place:

I got to know Perry a bit while packing this stuff, and he told me that he had sold 2 Penske trucks full of airplanes and airplane parts to a fellow before me.  They put 7 airframes into those two trucks along with hundreds of boxes and bags of parts!  There were two fairly complete Luscome airframes, a Cessna Skymaster, and 4 other airplanes that I forgot the names of!  Including the Prowler kit, Mike had 8 airframes and all of the associated "stuff" to go along with them shoved into that shop!  Plus, he still had a small workspace with a small mill and other tools to fabricate parts.

Anyway, it took me several weeks this year (since I was at Perry's) to sift through all the stuff.  I incorporated things with similar things that I already had, made room for the things I didn't already have, and inventoried the kit that I got from him.  Turns out that the kit is about an 65-70% complete kit.  Most all of the wing and fuselage parts are included.  The cockpit framing sub-kits and the FWF items were the most incomplete part of the kit.

Once again, I had to resist the urge to just take this kit and start building an airplane!  I am trying to remain focused on rebuilding Prowler Aviation and re-tooling for production of kits.  But, when you find 70% of a kit that has very well made parts in it, resisting the urge to just start putting them all together is very irresistible!  I may have a buyer that is interested in this kit, and I will help him fabricate the remainder of the needed parts.  If not, then I will probably just hold onto the kit for a while and fabricate the missing parts over time and then sell the kit when I have it completed.

So, right now, Bryan and I are sitting on at least two kits that may become available, soon.  More to follow. 

8.   Aircraft Available - Currently, I am aware of 2 flying aircraft that are for sale. 

George's airplane (Kit #5) is still for sale:

 

Also, unfortunately, Bud has indicated that he is going to sell his Prowler.  This is from a recent email:

To all,
Since I can not afford to fly this airplane as much as I would like, I
have decided to sell. It will be a great loss, but maybe someone else
will be able to do justice to a great machine. Within a few days, the
airplane will be listed.
Bud

Here are some pix from a few updates ago:

I am very sorry to hear you have decided to sell your Prowler, Bud!

If you are interested in either of these aircraft, please use the feedback link on our website:   http://www.prowleraviation.com/contact/contact.html
I will put you in contact with the owners.

That's all I have for this update.  Thanks for taking the time to read about what is going on here at Prowler Aviation.  Hope you are all having a great spring season.