Go with the flow

The way to fly

A B747 model being used to assess wake turbulence in the vortex facility at NASA Langley. (NASA)

I’ve been reading aerodynamics books over the last month.

I know. So cool, right?

I don’t apologise. I find the subject fascinating and the more I learn, the more it makes me want to find out. I have it so bad that I find the engineers at NASA JPL and Langley genuinely cool. Sigh! I guess there are far lesser people I could admire.

But consider what they do. The engineers at Langley had developed and fully tested an entire family of 78 four-digit airfoils by 1929 – including the numbering system to denote them – along with cross sectional illustrations for the whole lot. They’d also completed performance charts, created from endless, painstaking studies in the Langley’s High Pressure Wind Tunnel.

A sample of the NACA airfoils that had been derived in the Variable Density Tunnel and published in August 1929. (NASA L-05334)

The results made it easy for engineers around the world to asses and analyse airfoils for each aircraft design mission. What’s more (and here’s where you’ll appreciate how much of a geek I am) some of them are truly beautiful. 

I’m not too taken by the chunky, high-lift/low-speed thicker sections, but some of those finer shapes in the xx09 and xx12 series are enough to make me swoon!

(Click to enlarge image, and see for yourself.)

The wing is the thing

A nice top-down comparison of the F-16XL and a standard F-16, taken during the UK’s Farnborough Air Show, September 12th, 1982. (USAF DFSC8309387)

At the other extreme are projects like the F-16XL ‘Scamp’, which was originally developed in the late 1970s as a supersonic flight technology testbed. It was also considered as a ‘big wing’ strike fighter version of the ‘Fighting Falcon’, but lost out to the F-15 Strike Eagle.  

NASA retrieved the two prototypes from storage in 1988 and used them to tests a range of boundary layer control devices, including active suction wing gloves with laser-cut 0.0635mm diameter holes drilled between 0.25 and 1.40 mm apart by engineers at North American Aviation.

A model of the F-16XL undergoing basic flow visualization, as part of NASA’s High Speed Research Program. The smoke flow has been illuminated by sheet laser lighting. (NASA)

The F-16XL’s ‘double arrow’ delta wing was 120% larger than that of an F-16A, and the fuselage was 1.4 metres (56 in) longer. The enlarged wings gave the ‘Scamp’ a 25% better maximum lift/drag ratio in supersonic flight, while the wet wing tanks meant an 82% increase in internal fuel capacity. In short, the F-16XL could deliver twice the load, 40% farther, compared to the F-16A. Amazingly, for the early 1980s, the engineers also made extensive use of carbon fibre to save weight. 

From Falcons to Eagles

The irascible, bellicose and brilliant Colonel Don Blakeslee, Commander of the 4th Fighter Group from January to September 1944. (© IWM FRE5321)

Still, while the lure of aerodynamics occupied a chunk of my time, I have been working on airscape too. In fact, I’ve almost finished two posts that sort of got away from me, running to over 3,000 words each – and I still need to finesse them.

The first is a piece about a WW2 pilot that should be better remembered and yet, as so often happens, has almost disappeared from history. Not for long! I’m not going to give away too much at this point, but I know a few of you are interested in 8th Air Force P-47/P-51 pilots, so it should be a bit of a treat… We’ll be flying with Colonel Donald Blakeslee’s famed 4th Fighter Group, the ‘Debden Eagles’, after all. 

My second big piece follows up on the ‘promise’ of last month’s editorial, to start taking a closer look at the future of general aviation and private flying. This one ain’t pretty, but I think it needs to be published.

Even though I’m just an armchair strategist, I think about GA’s future most every day. The issues are as complex as the industry itself. All I’ve really figured out is that something needs to be done – like, now – and I’ll tell you why. I don’t have a silver bullet solution (if there even is one), but if I can make a meaningful contribution to the conversation, I’d regret it forever if I stayed quiet.

And that’s not all

There’ll be a second part to this GA issue too, hopefully with some suggestions and a bit more optimism. I can’t help thinking that if enough people contribute their energy to the problem, we’ll power someone’s ‘lightbulb moment’ somewhere, sometime. Let’s make it soon.

For a bit of easier going, you can also look forward to a couple of shorter post, to hold the big ones apart. And you won’t be surprised to learn there’s an aerodynamics theme developing there… 

It’s going to be a busy month!

9 thoughts on “Go with the flow

  1. Bet you would have loved to have met Barnes Wallis! Aerodynamics is a fascinating subject, but one that for the most part, I find just a bit TOO technical! I get the basics of it, but that is as far as I go!

    1. Yes, there’s a few people I’d love to have met: Barnes Wallis, Reginald Mitchell, Bev Shenstone and, across the pond, Edgar Schmued. I could go on and on. My maths is pretty rudimentary in comparison to those greats, but I seem to have no trouble visualising flow over, under and around aerodynamic shapes… Actually, I would have just poured beers and listened to the others talking!

  2. It certainly is a fascinating area of study and one that looks even more impressive in pictures. These wind tunnels and aerodynamic test facilities are in themselves remarkable and worthy of reading about. As for Blakeslee he was another of the USAAF’s greatest, I have included him in my Debden posts myself – a fascinating man.

    1. Shh! I’m planning a gallery of wind tunnel images for later in the month. And I can’t argue with your summation of Blakeslee. I have a couple of documentaries where he was interviewed and I’d only add – that wasn’t just his war face. He carried that bellicose, twinkle-in-the-eye charisma his whole life.

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