Saturday, June 23, 2007


Sometime in early June there was some time available to put the hydraulic press that we had acquired from George back together. After getting the hydraulic ram re-built and tested it needed to be reinstalled into the press and have the top and bottom beds re-installed. It may not be visible in these pics, but there is a 1/2 inch piece of plate steel inbetween the frame and the wooden bed on the top and the bottom. The one on the bottom is even more massive because of the large stiffening flanges that are welded to the collar and the 1/2 inch plate steel. The collar merely sits on top of the hydraulic piston. The ram is actually a 50 ton bottle jack that has an auxillary port.
Via that aux port you can put pressurized hydraulic fluid directly under the piston and run the press. For now, it is just operating with the jack via the jack handle - you know, the old fashioned way! But it's good enough to allow for testing temporarily. Sometime
in the fall we will build a small hydraulic power
pack to run the press more practically. During our test runs we will look to see how much pressure is required to press the pieces that we need to make. This will determine how big (psi) system we will need. As you might image, it also determines how much $$$ it will take to build that system - the higher the PSI the more the $$$ needed to build it.


If you look back to the last "Updated Plan" I think you'll find most of the items that were layed out there have been completed. There are a few exceptions - begining the wing assembly being the most notable. However, it's always good to have goals, so here are ours:

JUN '07:
1. Finish installing Evaporative cooling unit.
2. Work the day job to make $$ and time-off in JUL for AirVenture.

JUL '07:
1. Work the day job to pay for AirVenture in AUG.
2. Family vacation(s).
3. AirVenture! The entire week!

AUG '07
1. Locate, buy, and ship (or go get) the majority of the metal needed to build our Prowler.
2. Work the day job to pay for AirVenture and metal (see #1.)
3. Begin work in earnest to build parts of our first Prowler:
Dave - Rudder, Elevator, Horz Stab, Vert Stab
Todd - Wing

SEP '07
1. Continue work outlined above.
2. Build a hydraulic power system for the press.
3. Squeeze in time for Reno.

OCT '07
1. Build a better retaining wall and water drainage system behind the shop.

Hot News - IT'S HOT!!

It's been a while since the last post. Longer than planned, but we have both been working a lot at the real (day) jobs in an effort to keep our financial houses in order.

Since the last post, it has gotten pretty warm in northern Calif. Typical summer - hot and dry during the days. The nights are much cooler - mid 60's currently. In any event, the shop is in need of daytime cooling. So there is now a window a/c unit permanently installed between the office windows. It was a modest 2 day project in all. Next up is cooling for the main shop floor. Word around here is that evaporative "swamp" cooling is the way to go. So late last year Home Depot had the last remaining units (mostly damaged) on close out. I got a really good deal on this unit and picked it up.

One of the louvered panels was damaged, but was easily replaced by calling Champion. Total cost for the new unit: less than $90 without the motor. The motor and a few other parts will provide cool air for the main shop floor for less than $200. After talking with a few folks with more "swamp cooling" knowledge than us, we finally decided on a place to install the unit. It's going to be on the exterior north wall with the entry hole cut just under the ceiling.

With some odds-n-ends angle iron laying around, we fashioned up a bracket to hold the unit to the wall. This is a pic of the outside support system.

On the inside will be an 8-10 foot angle iron (3 inch flanges) to distribute the approximate 450 lbs load along more of the wall. The inside and outside supports will be lagged into the wall studs, and then the two halves will be bolted together at several places with all-thread through the entire wall.

In the last pic (below) the 20"x20" duct will enter the shop centered on the windows and from the top of the wall down to about where the clock is.

Evaporative cooling works well in this area because of the low relative humidity.

Theororetically, an evaporative cooling unit can cool air from it's ambient (dry-bulb) temp down to it's 100% humid (wet bulb) temp. Like any system there is never perfect efficiency, but a well maintained unit can achieve 70% efficiency.
We did a recent sample calculation using current data and found:
Dry bulb temp: 99 deg Farh.
Wet bulb temp: 65 deg Farh.
Air temp entering shop = 99 - .70(99-65) = 75.8

Not too bad. Unlike A/C however, you don't try to recycle air in a "swamp cooler" system. You actually have to provide about 2 sq. ft. of open window for each 1000 CFM of air moved in order to maintain proper temp and fan motor loading. More later.