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Saturday, May 31, 2008

Saturday Matinee: Resin Infusion Experiments

A couple weeks ago I did a test infusion on a small piece in an attempt to replicate what might happen when I infuse the rudder. I shot a video of it which you can watch below. All in all things went ok. The flow medium caused the resin to flow to the vacuum port a bit too quickly, so I will adjust how the flow medium is layed out when I do the rudder.
Definately a riveting video. Besure and pop some popcorn before you view. It is about 3-4 minutes long, time compressed. The actual infusion took about an hour.

Saturday, May 24, 2008

Gonzo Engineering

Ok. So I was browsing the Microship website (linked on the side column), and came across the owner's article titled Gonzo Engineering. In particular, this section of ten rules that apply to any large engineering project. I had to laugh, because it is true. Being an engineer myself (software) it is spot on with my experiences and even applies to the Westsail project. This is why we are not publishing "hard launch dates" ;-). It is written from the perspective of his electronics projects, but I think it applies to all disciplines. Engineering in a Nutshell What actually happens is much more organic, and I’ve noted with amusement that, despite protestations to the contrary among the engineering population, it’s typical of the way things usually work in industry. Here’s how to manage a huge, complex project:
  1. Accept going in that your first tentative decomposition of the fundamental concept will yield an over-simplified TO-DO list, distorted by misunderstanding of key issues.
  2. Avoiding all the items labeled TBDWL (To Be Dealt With Later) or ATAMO (And Then A Miracle Occurs), dive headlong into the well-defined parts, finishing some of the electronic design so early in the game that it is guaranteed to be obsolete before the physical substrate is built.
  3. Blunder ahead on the non-obvious parts, getting pleasantly distracted by learning curves and occasional moments of certainty, only to discover basic flaws in your reasoning.
  4. Now that you are forced to re-think the initial concept, map it onto newly recognized reality to yield a fresh TO-DO list (with new lab notebooks and computational tools to keep things lively) and another cycle of enthusiastic activity.
  5. Repeat steps 3-4 countless times at varying levels of abstraction ranging from the entire system down to individual components.
  6. Meanwhile, since technology evolves with frightening rapidity, acknowledge the fact that any computer-based system is such a moving target that if it’s not completed quickly, it will be irrelevant by the time it ships.
  7. Respond by simplifying the design, further refining your objectives and abandoning dead-end ideas while doggedly pursuing others that have come to represent too large an economic or emotional investment to allow a graceful retreat.
  8. Compromise here and there, bang out a few things that weren’t on the list, then add them and cross them off to make yourself feel good.
  9. Get totally sidetracked a few times, and periodically dive into major development marathons to meet public deadlines like trade shows, pulling all-nighters in PFD mode (Procrastination Followed by Despair).
  10. Announce new completion dates whenever a previously predicted one has passed, and keep driving your PR engine to maintain interest during a process that is a textbook illustration of Hofstadter’s Law (“Everything takes longer than you expect, even when you take into account Hofstadter’s law.”)

From "Gonzo Engineering" by Stephen K Roberts. The rest of the article is worth a read.

Sunday, May 11, 2008

Rudder Glass Fitted

Nice day yesterday. Not too hot, not too cold and best of all, no rain.

Got nearly all the glass cut and fitted for the rudder. All except the last layer of chopped strand mat. What I had left on the roll was not enough. Add CSM to the list.

I also took tried to fit bagging film and peel-ply for the infusion. Ran out of those too. So, add peel-ply and bagging film to the list.

This infusion attempt will be critical as a lot of work has been put into the rudder and I would hate to have things go south. So, I have been putting a lot of thought remembering past infusion projects, what worked well, and what didn't.

The key is predicting resin flow. In boat production environments, they have fancy software that does resin flow predictions to help in the setup. I don't have the luxury here, just previous experience.

Considering this rudder just a "small part" and is more or less a "flat" piece it shouldn't be too hard. Current idea is to provide multiple vacuum ports along the top, drawing up resin from multiple feed points along the bottom. The vacuum ports will be valved to help control saturation should one area start to get wetted out before the others.

The blue Colbond flow medium I have will be used on the surface of the rudder, but not on the edges. Special resin flow "strips" (EnkaFusion CX-1000) will be draped over the rudder from top to bottom, staggered every couple inches to help resin flow from bottom to top and will wet out the nearby glass. Need to add that stuff to the list as well.
More later as I finish the setup.

Friday, May 09, 2008

Ready For Glass

Got all of the rudder foam glued and shaped. With rough faired along the trailing edge with filler compound. The picture is not very good as it was taken with a camera phone.

Hope to cut and fit glass this weekend.

The most convenient tools used to shape the foam was the woodworking planes from Microplane. They make a metal disc that replaces standard hook/loop 5 inch sanding discs, which worked really well.

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