Friday, October 8, 2010

CAD Burnout - But Progress Continues!

Welcome Back! Thanks for checking in on us.

Well, after working on CAD drawings of Prowler parts for what seems like every spare minute of my life during the past year - I've officially reached burn out. But, that doesn't mean that progress towards production is halted. It just means we needed to strike out in a different direction for a while and do something a little creative - to keep the motivation level high.

In this update:
1. OK, Still Doing some CAD work
2. CNC Plasma Fixes
3. Ray's Prowler is Getting Its FWF
4. The New Prowler FWF Solution & Mock-up
5. Builder Progress Reports
6. Future Home of Prowler - East
7. Update on George

Here goes:

1. OK, Still Doing some CAD work - While CAD burn-out is evident, it has almost become a way of life, so the Prowler Part count-down does continue. The Flap Sub-kit is now complete and the Main Landing Gear is about to start. In addition, I have also had the opportunity to CAD up several parts to use in fabricating the new Prowler engine setup. See the next item for more of this. There have also been several CAD jobs for various parts that have come up in association with builder requests. So, we are staying CAD "proficient" thru the doldrums.

2. CNC Plasma Fixes - We found that while cutting round parts with the Prowler Plasma machine, perfect circles were coming out with two flat sides. Investigating the cause of this lead to some side-tracks and an eventual solution. Turns out, the flat sides were happening where the X axis was changing directions during a cut. Checking into the mechanical aspect, it was found that the gear rack on the X axis had dropped down and there was too much backlash in the gears. While fixing that, I found out that one of the studs that held the gear rack had broken off in the frame and was just rolling over when trying to tighten it. So, off with the gear rack and out with the MIG welder. Problem solved, until the gear rack bumped the gantry and the actual gear track section (all 4 feet) popped right off the rack. So, that lead to researching how and why this gear track was bonded to the rest of the rack. After, finally, finding the special Loctite product used to bond this track to the rack, it was fixed (actually re-bonded all 8 feet just for piece of mind). Here are a couple of pix of the re-bonding:
With the gear rack re-installed the problem was still there. Circles were still coming out with the two flat sides. So, assuming all the mechanical possibilities were covered, the problem had to be in the electronics. While testing one time, I noticed the table visibly shaking while simply running the X axis in a (presumed) continuous, constant speed move to the right and/or left. We ran some more tests and figured out that the X axis (stepper motor) was missing steps badly. After swapping motors, driver cards, and inputs we eventually logically deduced that the X axis motor driver PC card was at fault. After a bunch of research (again) we ordered and installed a new card:Problem solved! Since then, we have cut several parts with no problems. Here are some pix of parts cut out for another item in this post (FWF Mock-up) discussed below.

The plasma cutting table seems to be getting much more reliable and/or the operator is getting better. In any event, it definitely makes fabricating specialty parts a breeze.

3. Ray's Prowler is Getting Its FWF - Ray is making really good progress on his Prowler lately. During the past month I've visited him several times and even got to help him hang is motor during one visit. Check it out: The next visit, Ray had added several of the various plumbing lines and other connections: Since then, Ray has added several of the engine compartment framing pieces and the spinner attachment parts:Ray plans to have the engine cowlings on and fitted by the end of Oct. Then the plane will be trailered up to his sheetmetal guy to fabricate and fit all of the complex and compound skin parts (wing root fairings, etc.) Nice work Ray! Thanks for letting us be involved with your progress. The Plane is looking GREAT!
4. The New Prowler FWF Solution & Mock-up - All this work with Ray on his FWF, combined with the CAD burn-out, got me thinking about the new Prowler's FWF system. We have decided that the new Prowler Aviation is not going to be in the engine building business. At least, not initially. Getting the airframe finished will be challenge enough. George's engine system, while appealing, is just not practical. It requires a massive amount of mill, lathe and "gear-head" work to get one working FWF system. With Ray constantly telling me that "You need to get the build time down!," it is very apparent that the old way isn't going to work.
So, here is the FWF plan for the New Prowler: Order a stock crate LS1 engine with computer harness, add one Geared Drives PSRU system, top it off with a (yet to be determined) propeller and hub combination and go fly. (At least in theory.) We have been watching Bud Warren and his Geared Drive system for years and we're convinced that it is the best overall solution for the Prowler FWF - if it will fit! If it does, you just might see the Prowler listed with the rest of Geared Drives FWF packages. Check out their website at the link above.
So, will it fit? There-in lies the catch. The only way I know of to prove it is to mock-it-up and see if the original Prowler engine compartment components will fit around this new system. If not, it will make it easy to see what changes will be necessary to make it fit. I also thought that it would be a good time to tackle this with Ray working on this part of his airplane. By sort-of paralleling what Ray is working on, I can benefit from him allowing me to help with airplane. I've already collected tons of data, measurements and part information. I even found out there are parts of this airplane that I didn't know existed - Humph! But with a little help from our friends, we'll get it all together.
OK - I don't know if there is a standardized way of doing a FWF mock-up, but here's what I've done:
A. Collected damaged, broken, and worn-out parts of an LS1 engine:
B. Build a cart (so you can move things around in a shop that is starting to get pretty full!) C. Put the engine parts together and put them on a stand that can be used to move the engine in six degrees of freedom as needed:

C. Research the Geared Drives system and make a mock-up of the PSRU. Thankfully, there is just enough information available on their website to be able to CAD up the necessary parts to build a full-scale mock-up.
D. Add very contrasting paint: E. Cut out, paint and and add flanges to a firewall: F. Put it all together: In the next week, I'll be adding as many other engine compartment components as possible. Cabi and I will be getting together to fabricate the "horse collar" that attaches to the motor mount and makes of the forward framing that the engine cowling skins attach to. I'll also be adding longerons and eventually skins - although that will require the purchase of, and learning how to use, an English Wheel. That might take a bit more time.
So far, what is evident is that the engine will sit at least 3 inches lower than it does in George's design. This is a result of the Geared Drives design has the prop output shaft centerline 3 inches higher than George's design above the crankshaft centerline. Since the engine in the Geared Drives design sits opposite to what it would in a car (George drove his PSRU from the front of the engine), the rear sump oil pan might get too tight. This could require a switch to a front sump oil pan, which would put it in the back of the airplane engine.
So, there it is. There will be more to follow, but initial indications are that this new FWF will fit in the old Prowler engine compartment, with some minor changes.

5. Other Builder Progress Reports - Here is a quick run-down of the recent info I have on current builders. Some of this info is third hand, but from reliable sources.
A. Chuck Westcott is still working on ignition issues. His engine man has been busy with some other projects, but work continues and he plans to have his Prowler flying again soon. He wants to get the 40 hrs flown off and then the plane will go up for sale.
B. Bud Tedesco - Still working on the gripe list from the first flight. Hope to hear about a follow-on flight soon.
C. Steve Rogers - Has flown his Prowler a few time this summer up in SEA area. He has most of his gripe list taken care of and the plane is working well.
D. Bryan Davies - The day job has stepped it up a notch or two, so he's been working a bit more. However, he's working on building the fuselage. He also, finally landed a deal with the Delta Hawk guys and has put his deposit on his new engine.

6. Future Home of Prowler - East - Dave has spent the majority of the past year moving out of the old homestead, moving it all up to the BNA area, moving into a rental across the runway from their future home/hangar, and now actually building the new homestead. Here's a couple of pix:

Yes, that's a grass strip in the background. Beautiful house on a great property Dave!

7. Update on George - Recently, George was working on his 1963 Starfire and took a fall. He fractured his hip and needed to have a pin put in. He has had the surgery and made it back home last Tues. We wish him a speedy recovery.