Random Seens

What do spinning props look like?

'Another day': Hurricanes from 17 Squadron RAF in northern France, June 1940

What does a spinning aircraft propeller look like?

You’re thinking I’m daft. Anyone who’s ever seen even an office fan knows what a spinning prop looks like.

Right. It’s just a blurred disk.

So why is it that in almost every photograph you’ve ever seen of a prop aircraft you can not only see but in effect count the propeller blades?

The answer is obvious of course: photographs are a sliver in time and if you are going to catch a moving aircraft without showing it as a blur, you need to have a fast enough shutter speed that it will also ‘stop’ the propeller.

The effect of this will vary with the speed of the prop’s rotation - which in part depends on the different phases of flight - and of course the shutter speed.

So the question that I have been grappling with is: what looks ‘right’?  

Dead engine

I want to know because, in a new departure, I am developing a range of aviation-related digital artworks (for want of a better term).  

These are photographically based, but the source material features a motley variety of prop rotations - from the total blur (rare) to the stationary (which looks just silly in my opinion - as if the engine has seized in flight).

I found that, to render them into photographic (or photorealistic) backgrounds it was easier, usually, to recreate the spinning prop from scratch. So I could make it look like almost anything I wanted.

I debated with myself whether to mimic the effect of an artfully chosen shutter speed - good blur but with discrete blades visible - which a crack aviation photographer will usually strive for. Think Paul Bowen, for example: http://www.airtoair.net/gallery/gallery-bombers.htm.

Or whether to recreate what you actually would see if you were right there. After all, in a typical air-to-air scenario, where is the viewer? Hanging somehow in space?

After a faltering start I’ve plumped for the latter. In the Hurricanes image above - with the viewer standing on the ground, I suppose - I started with a single prop blade, painted the tip yellow, and spun it into a circle (this worked better than spinning three blades). Then once it was pasted onto an aircraft I resized it and altered the perspective to fit - and adjusted opacity right down. 

[UPDATE: 19 Feb 12]  In response to online discussion of this approach and a review of more photos, I then also added some reflected sunlight 'shimmer'. This needs to be related to the surrounding light but i think it adds a good sense of depth and movement to the props. 

But I’m far from being sure about all this. So comments welcome please (and “stick to jets” is not helpful, thanks!).

Pure sky

You probably know that I have a thing about sailing, but my first love was flying. It's just that circumstances over the years made it less accessible. Less accessible but not inaccessible.

I was at John Lewis buying a vacuum cleaner (can I get some product placement dosh here please?) and emerged to the most fantastic late afternoon cloudscape as heavy rain showers rolled across the South Buckinghamshire landscape.

What has this to do with flying? Well, Booker airfield - properly, Wycombe Air Park (EGTB to pilots) - is just around the corner and I figured it would afford an open vista. Which it did, as you can see. The clouds really were something to behold. It is unusual to have a backdrop so dark that you'd think I must have walloped a hefty filter over it. But no, this is unretouched apart from standard tidying up.

The plane taxiing for takeoff, by the way, is a Robin DR 300-180R,  a French design made by Avions Pierre Robin. This particular one, registration G-BLGH, is used as a glider "tug" by Booker Gliding Club. In other words it tows sailplanes to altitude then releases them to realise their true function.

I made several photos over a cup of tea at the airfield cafe, then headed along the ridge a little way to the outskirts of Flackwell Heath and contemplated the landscape there. Eventually I made up a panorama of that view too.