Saturday, August 29, 2009



Just a quick post to update the latest Prowler progress:

1. Catch up on the Vert Stab.
2. Horiz Stab Work
3. Computer Modeling Parts
4. Builder Update

1. Catch up on the Vert Stab. – In the previous post I mentioned that Dave has been working on assembling the Vert Stab Subkit. Here are a few pix of his handi-work.

2. Horiz Stab Work - Dave's been itching to get to more assembling and I wanted to do something besides work on the plasma setup, so I decided to get some creative work going for a change and started fabricating the parts for the horiz stab subkit. These 8 parts were about 9 hours of work:

Now they have to be heat treated, since they are formed from 2024-O (soft) material. Here are the horiz stab spar parts and cover plates cut out and waiting to be bent up in the sheetmetal brake. I used a buddy's sheet metal shear and it made cutting these out very easy.
Other horiz stab parts:

3. Computer Modeling Parts - Well, we have begun in earnest to model all the parts that make up a Prowler. This will be needed to setup the CNC plasma torch system to cut the flat parts. We purchased copies of BobCAD-CAM and are in the learning to use it process (steep curve right now). It's actually a very powerful program for the price and fairly intuitive - once you watch several of the video tutorials. Here are some examples: The vert stab aft spar;
Main Landing Gear Pivot Link:
Tailwheel Strut:
Close up of the 3D view of the strut - BobCAD-CAM ver 23 does well with the 3D:

Now, only 687 more parts to go (just guessing)!

4. Builder Update - Ray Siem reports that Chuck has his airplane and engine back together and the engine is running well. His problems apparently stemmed from a damaged, or lack of, the mechanical stop in one of the distributors. On one of them the cap had a hole in it where it looks like part of the centrifugal stop system exited the scene and it let the engine vacuum advance run way to advanced. He reports that the engine is running well with coolant temps in range and no noticable issues. He is going to continue to test run the engine while he is going also going thru some medical issues. No date for the next test flight, but we'll keep ya posted.

That's it for this post. It's late and crew services could call in 4 hrs. Thanks for checking in.

Saturday, August 22, 2009


Well, it’s been several months since the last post, but if was for good reason. During that time a lot was happening. In this update:

1. Prowler Territory (was) Under Siege
2. Vert Stab Build
3. CNC Plasma Success
4. AirVenture 2009
5. Horz. Stab Started
6. Repairs to Bridgeport and MLG Forks
7. Builder Updates
8. Event Horizon

1. Prowler Territory (was) Under Siege - On May 7th, Todd was notified that an agency call TANC (Transmission Agency of Northern California) was planning to build a 500 KV transmission line with 150 foot tall massive towers across 2/3 of his property.
The project was eventually abandoned in Jul. But, from May 7th until July 16th it consumed every minute of every day that he wasn’t making a paycheck helping to form and work on a grassroots opposition to TANC (with over 400 other Northern California residents affected by the same project). In all, the project was proposed to be over 600 miles long and affect some 7,000 land owners. On July 7th the Sacramento Municipal Utility District withdrew from the project and took $0.5B with it. Within a week all the players pulled out of the project and all landowners got their properties back. Good riddance.

2. Vert Stab Build – During the time that Todd was fighting TANC, Dave was working on the Vert Stab subkit and creating the associated portion of the Prowler Assembly manual. Using the old version of the assembly manual, Dave completed most of the vertical stabilizer including priming of the parts. The final assembly has not yet been completed because we are looking into re-doing the rudder hinging system. Once we complete this re-design the remainder of the vert stab will be assembled. Sorry, couldn't find any pix this time, we'll post them in the next update.

In conjunction with building our subkits, we have always planned to do a complete re-write of the entire Prowler assembly manual including new text, pictures, drawings, graphics and, if need be, video of assembly. Dave has made some very impressive changes to the manual while working on the vert stab and our future customers will, no doubt, find this new format much more readable and easier to understand. Nice job Dave.

3. CNC Plasma Success – After over 8 weeks of not getting into the shop at all, Todd was able to get back to work on Prowler business. Some of the recent accomplishments include: Completed troubleshooting computer & software issues with the system that runs the CNC plasma table; Completed more modifications to the CNC plasma table; Learned how to CAD parts using BobCAD-CAM ver. 23 (great program) and then CAM the parts using SheetCAM; and most recently – did a complete dry run (with torch off) of a sample part in the CNC plasma system.
If all goes as planned, we should be able to begin using the Prowler Plaz system to proof the concept and start making our parts for our airplane. The idea is that once we complete our company aircraft using this process, we will have the ability to use this for limited production of Prowler sub-kits.

4. AirVenture 2009 - This week, Todd, Dave & Bryan attended Airventure at KOSH. As always, AirVenture was busy and impressive. The A380 as HUGE, the WK2 was interesting, the warbirds were awesome and the airshows were great. Bryan was able to make it for 3 days, Todd and Dave were around for most of the week. We didn't, and probably won't, have a vendor spot at AirVenture for some time. Since we don't yet have anything to sell, we're keeping a low profile.

5. Horz. Stab Started - Todd got a little time in the shop last week and started to fabricate the horizontal stab. We hope to have the sub-kit built and shipped off to Dave for assembly in the next few weeks. Finding somewhere to cost effectively heat treat the few small parts in the horz stab that were formed from 2024-O might be the hold up. More to follow.

6. Completed repairs to the power feed system on the Bridgeport Mill - George came out recently and had some left over stock that he had cut up to make the MLG yokes (forks). We start to use the mill and determined that the power feed was not working correctly. After some investigation it turned out to be a loose bushing deep inside the mill head. So, we had to pull the head, remove the set screws holding the bushing, re-drill the centering hole, re-install the set screws, re-install the mill head, tram the head to square it to the table and (several hours later) bored out one of the strut holes in one of the forks.
7. Builder Updates - We have updates this time from Ray, Chuck, and Bryan.

Ray - has been making really good (and impressive - as always) progress on his plane. He's currently focusing on the instrument panel and electrical wiring. He's planned out an impressive panel with all the bells and whistles. He has incorporated Dynon Avionics with full autopilot, an airliner quality gear operating system, and beautiful landing lights (see a previous post).

Chuck - has had to tear down his engine. Turns out there was an issue with the vacuum advance system in the ingition. There was no limit for the advance system and the engine was damaged. During the teardown Ray stopped by to get some pix of the PSRU and engine. The engine was almost back together when Ray was there and Chuck is planning to run the engine again soon.
Bryan - is mostly done with the wing and is beginning to lay out the cockpit floor in preparation for building the fuselage onto the center section of the airplane. He is also working on finishing the MLG doors and wheel wells. Bryan has decided to forgo the inner gear doors and his plane with have 737 style wheel wells.
8. Event Horizon - What we have coming up on the event horizon:

Prowler CAD work - We are beginning in earnest to start modeling all of the parts needed to build a Prowler. This will happen over time, as we will go back and model the parts that we’ve already made via other means and then move on to modeling the parts for the work we are currently doing. Again, the idea is that by doing this, we will eventually end up with the entire aircraft modeled in a CAD format when we finish our company aircraft.

Prowler Plaz Testing – With the completion of a perfect test run of the Prowler Plaz system, now the real learning curve begins. We must do a series of test cuts to determine the ideal parameters to use for getting the best cuts on each type and thickness of material to be cut. These parameters include things like the best tips to use, the current setting, the optimal pierce height and cut height (controlled by voltage) and feedrate (cut speed). These parameters go into a library contained in the cutting system program that can then be recalled very quickly anytime a similar material is cut. But, the initial testing will take time to build that library. In addition, the plaz system needs a bigger air compressor to be installed and we are going to install a refrigerated air dryer to get the best cuts possible.

Main Wing Spar - The goal at Prowler West is to get the entire main wing spar fabricated, prepped and put into the wing jig by the end of the year. This effort is in direct competition with the above items for time - so some compromise will need to be made, but that's the goal.