rgmwa

Like Morry Hummel, Vans have over time incorporated improvements in the RV-12, and no doubt the other RV models, based on suggestions and modifications made by the early builders and documented on Vans Airforce website. Even yours truly can claim a couple of very modest contributions that have since appeared in the current kit.

Agreed Onetrack. I've read the Silver Centenary story and also had a good look at it and watched it fly more than once. It's hangared at Serpentine, where I keep my plane. Ford did a remarkable job - it looks right and in engineering, that's usually a pretty good guide as to whether something is right. And as you say, just because an aircraft was `professionally' designed doesn't mean that it's going to be any good. There are plenty of examples of professionally engineered flying crocks in the history books. Nor does having formal engineering qualifications make you a gifted designer, just

Yes, I’m happy to build and fly a plane that I know has been well designed and tested, and to make relatively minor modifications that I know won’t its airworthiness. Nevertheless, even though I’ve spent the last 40 years designing structures for a living, I’d still think twice about tackling an aircraft without doing a lot of homework. Hats off to the true experimenters though.

It’s not the ‘design by eye’ part that would would worry me. It’s the ‘confirm by test’ bit that would make me think twice about buzzing around at 1,000 feet to find out which part of my design needed improving.

The struts are not very long which is good, but I'd suggest "When in doubt, make it stout!"... especially when your life depends on it and you're not sure what the loads are. There's a big difference in strength and stiffness between 20 and 25mm tube for the same wall thickness, and steel is a lot stronger than aluminium (obviously). Also if you're putting bolts through it, the bigger tube will lose relatively less cross-sectional area.

How long is the strut?

I agree with Yenn. You need to have a pretty good idea of the tension and compression forces in the strut and its fittings under all loading conditions, and also how to design in timber if you're not building from a plan.

The highest grade I found for seasoned hoop pine after a quick search was F17. It's a softwood and AS1720 (Timber Structures: Part 1 - Design Methods) - gives a characteristic bending strength of 42 MPa and tensile strength parallel to the grain of 22 MPa for F17. However, these basic values need to be modified by a whole lot of factors if you want to design something.

I don’t think it’s racist to notice difference. It’s obvious that people from different places and cultures have different characteristics. The problems start when those differences result in differentiation and discrimination. We have many different races and cultures here in Australia, but compared to many other countries like the US, we do remarkably well in creating a pretty homogeneous society. I’ve always thought the Australian accent is a great unifying factor in smoothing out cultural differences over time.

I wonder about the Wandering Albatross. They spend many weeks flying day and night over water and you would think they might get caught in IMC. Even night flying would be tricky. I suppose they could land but taking off from rough water wouldn’t be easy. Interesting question.

Good news! Looks like overseas travel is back.

He makes it look easy. I spent some time watching one of these in action on the North Island a few years ago. It takes a lot of skill fly one of these in that hilly country.

Looks like those South Africans are in business for the long term. Good to see. Anyone know what a Sling 2 kit costs in Australian dollars?

Can't vouch for the Sling from personal experience, but it was designed to the EASA VLA standard with an MTOW of 700kg, so when it's sold as a 600 kg LSA, something has to give. However, I have an RV-12 and it does everything that Vans say it will do. My only complaint is that the standard 20 US gal /75 litre tank with a 912ULS is marginal for Australian distances on long trips. I've increased mine to 25 gal which works well, but the trade-off is that I can carry less weight in the baggage compartment with full fuel. A couple of other RV-12's over here have been modified in the same way. Howe

Scratching your nose or waving to a friend is probably not recommended either.