Using Dope

Today we finally had a class together after me missing a few due to Division Office commitments. Now that the fuselage, tail feathers, and wings are constructed, it's time to coat the entire surface in aircraft dope, prior to covering. A trip to the hobby store got me some dope, as well as a few cheap brushes to use. Opening the jar brought back memories of dad's shop and my basement as a kid, and a stark reminder of how much this stuff stinks! Thankfully our location in the classroom is close to a window for ventilation, and the students did not complain too much about the smell. The thing about dope is that no amount of detergent of any sort gets it out of clothing, so I brought in a work coat from home to protect the students. Some rubber gloves were a good choice, too, as this stuff isn't great for your skin either. Two ladies tackled the painting today, and we'll be ready to start covering on Friday. I have to remember to bring a razor blade or an X-acto knife to cut the tissue paper as well.

Slow going...

A variety of delays have kept us from proceeding with the project as fast as I'd like. Last class had me away (again!), but prior to that, a couple of gentlemen did a bit more work on the fuselage -- the firewall (even though the "engine" is a rubber band), and a few more bulkheads were put in place. Just the landing gear remain prior to covering. I'm reminded that 20 years ago, I found that balsa model glue does not work so well on metal... so I'll bring along some 5-minute epoxy from home, to glue the wire struts to the landing gear struts to keep them in place. These things are tail-heavy by nature, so a bit of extra weight ahead of the C of G shouldn't hurt -- the epoxy will be heavier than the balsa glue...

My Turn

The November 5th class saw most of the students preparing for their exams on the 7th and 8th -- ELA worksheets and review were out, as well as some Math stuff. We also did another Math practice sheet, and all students are doing either Integer Multiplication or Division. The horror that was Integer subtraction (just in time for Halloween!) has passed.

Once the quiz was done, I decided to do a bit of work on the plane myself. Scott's work on the bulkheads seemed to "take", and so I worked on the fiddly task of reinforcing the fueslage with 16-odd short stringers throughout its length. It all went together OK, and another eyeball check of the thrust line seemed straight, despite the wonky bulkheads. A few more pieces need to be put in place, including the landing gear struts with the wire reinforcements, and we'll be ready for covering.

Hiccups and Hurdles: Thrust Lines

Scott stepped up this morning to work on the plane. Our goal today was to get some support stringers installed to create the "box section" part of the fuselage, but prior to this I decided the firewall (area behind the engine) needed to be put in place first. We've come across a slight example of varying degrees of accuracy in the fuselage halves. Two main parts, a bulkhead aft of the cockpit, and fore of the rubber band pillar are a tad crooked, in opposite directions. This made "sighting" the firewall square to the rest of the fuselage a bit difficult, as we had no real "square" datum as a reference. Eyeball engineering took over.
Scott came up with the smart plan to cut out a section of the fuselage to square up the first piece of the firewall. Some delicate cutting on his part, and a steady hand helped. I just stayed out of the way, as my initial attempts to help led me to clumsily damaging a piece of the wing... luckily it can be easily repaired. I think I'll do a quick mini-lesson in the future on "thrust lines" -- the fact that a few bulkheads in the fuselage are not square shouldn't be too much of an issue -- making sure the propeller, when installed, is pointing "straight" out of the front of the plane IS a key issue. We'll end up having a "Nascar" airplane; one that turns left or right only!
Coming across these hiccups is part of the learning process. Perfection isn't the goal, but accepting hurdles as a fact of life, and taking the time to fix them is important. Assembly lines in real life are designed around perfect accuracy every time. That being said, even the new Airbus A380 was built from scratch the first time!