One of the things we all have to do when fight testing an airplane is to fly it across the entire CG range – from full forward to full aft. In the case of a side-by-side two-seater, this generally isn’t too hard, because the CG range is actually fairly short. With a large four-seater (plus baggage), it can take a little more creativity to safely hold enough weight to get to the aft limit. By safely, I mean that we need to have the weight distributed in a structurally sound area, and SECURED so that, in the event of a mishap, it doesn’t break loose and become a missile aimed at the pilot’s head! Continue reading "Ballast Box"
Cockpit ergonomics are a big deal to me – and they are a slippery problem. I spent much of a career helping designers refine designs for man-machine interfaces, and part of the problem we had is that everyone had different opinions of what was “good.” And given the wide variety of people – both in size and shape as well as the way they think – coming up with good solutions was never easy. Continue reading "Getting a Grip"
The Monday after Christmas dawned clear, calm, and cold here in the foothills of the Sierra Nevada mountains of Nevada – perfect for flight testing (assuming you have thermal underwear and gloves)! It was time to get our Dream Tundra back in the air after significant belly skin upgrades. We also finished up a complete (early) annual condition inspection, seeing as how we took the plane out of service right after completing Phase 1, and this was a great opportunity to do a tip to tail inspection after the flight test phase. In addition, we’ve added a few things during the downtime – things we’ll be writing about in the near future in the pages of Kitplanes and here on the web site. These include a new angle of attack indicator from Alpha Systems AoA, and a T3 tail wheel suspension from Airframes Alaska, plus new stick grips from Tosten, and a pitch trim controller from TCW. We’ve also made a few tweaks to the Dynon Skyview, updating to the latest software – so there is a lot to test and report on! Continue reading "Tundra: Return to Flight!"
Sheet metal repair – that’s what I am talking about. I’ve written a couple of notes in the past few months about repairing the minor skin buckles in our Dream Tundra. It turns out that Dream has re-designed the belly skin, doubling the thickness, then adding another doubler over that. We asked them to double the skin thickness for the chin skin – and when all three part showed up, the number of holes to be matched, and the number of rivets that had to be drilled out and replaced was daunting. Continue reading "It’s Not That Bad..."
After several months of waiting on new pre-punched parts to be made and delivered by Dream Aircraft for our Tundra, we finally received a big box of belly skins and repairs are underway! If you remember, we (and other owners) discovered some buckling under the chin of the aircraft that were attributed to torque loads on a very thin (0.024”) skin section. The repair is to use much thicker material, and eliminate a couple of inspection panels that further weakened the area. While we could have made these parts (and indeed, we began fabricating them after the long delay – but stopped when informed that they wee ready for shipment), the pre-punched components fit perfectly into the existing holes in the framework, and require far less tweaking.
Yesterday we drilled out hundreds of rivets holding the cabin and nose belly skins in place, completing the removal process we had started a while back. Our arms are feeling it today, I’ll tell you! Lying on a creeper and holding even a lightweight air drill for a couple of hours is tiring. With all of the rivets removed, we were able to drop the skins and start cleaning up all of the rivet tails, aluminum shavings, and accumulated dirt that seems to creep into a structure over the years. The good news is that the fuselage framing is in great shape, and (most of) the holes aren’t enlarged from the rivet removal process. A few will need oversized rivets – but that’s the life of aircraft repair.
We had already made a smaller doubler plate ourselves using a Mylar pattern technique to match holes, but Dream supplied us with a new belly skin, doubler, and the thickened chin skin all of which fit perfectly, with only the need to up-drill the pre-punched pilot holes to final size. More drilling while lying on our backs – yippee! A good solid work day saw us to the point where all the holes are done on the bottom of the airplane, and we only have to work our way up around the sides – that will require some blocking and wrapping with cargo straps to bring the skins in tight.
Drill, deburr... repeat! That’s aircraft sheet metal repair. It takes the time it takes, but we can see some light at the end of the tunnel. Plus, we found those missing screwdriver bits and determined that there were no mice living under the floorboard of the airplane – so we’ve got that going for us!
I keep getting asked how our Tundra repair project has been coming along, and since I've talked about it here before, it is only fair to update the one or two folks that are interested in the progress. The problem, if you don't recall, is some buckling of the belly skins near the gear box. We've decided to address it in similar fashion to what has been experienced by a couple of other owners – that is with a skin doubler, adding a sheet of .032" to the existing .020" sheet metal. Although the wrinkles we saw were between the gear box and the firewall, the factory came out with a doubler for the skin behind the gear for the trikes and float versions – so since we’re in there, we figure it wouldn’t hurt to stiffen that up as well. Continue reading "Tundra Progress"