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204. Film star…

05/11/2015

How many of you had childhood dreams of riding a WWI aircraft into combat and opening fire on the enemy with your silk scarf streaming out behind you and the propwash from your trusty rotary engine forcing your face into an oily grimace? well, on Tuesday I got to live the dream, and I’m still coming down from the high.

We had set aside the whole week to try and get some film footage using a new 4k video camera for a demo.

We also wanted to celebrate the centenary of the first successful takeoff by a wheeled aircraft from a moving ship; Bristol Scout C, serial number 1255 flown by Cdr Towler, took off from the foredeck platform of HMS Vindex on 3 November 1915.

The forecast was simply terrible. Monday was foggy all day; rain was due to sweep in on Tuesday afternoon and remain for the rest of the week.

But we collected at Bicester on Tuesday morning, more in hope than in any serious expectation of getting any flying. 1264 was got ready, and the low cloud lifted just enough to get some circuits in.

The film crew wanted some shots of the aircraft diving on them, and so I took off and did about half a dozen circuits, diving down on the camera and being overlooked by the Kestrel Cam drone which was also fitted with the new 4k camera.

The preliminary results can be seen below.

 

Then it was time to see if we could emulate Cdr Towler’s takeoff.

Scout C 1255 taking off from HMS Vindex

In the absence of an aircraft carrier, we decided to film the takeoff and calculate whether the performance matched that of Towler’s.

We know that the Vindex was steaming at 12 knots. We didn’t know what wind she was steaming into, but based on the sea state in the pictures, estimated it to be around 10kt. The tailskid was set onto a trestle to ensure it was at flying attitude from the outset, with a release mechanism to allow the engine to be run up to full power before release.

Scout C 1246 on HMS Vindex including instruments

For our trial, we mounted a camera on the underside of the wing pointing at the wheel.

The wind for our trial was calm, so by recording the time each time the wheel completed a full turn, we could measure 1264’s groundspeed, and by counting the number of turns of the wheel from the point at which it reached 22kt until we achieved takeoff, we could see whether we could have got off in the 68ft of the Vindex’s platform.

Of course we were operating under some disadvantages. were had virtually no experience on type; Towler had been practising on a dummy deck for a good while. The Vindex platform was of smooth wood; we were taking off on a roughish grass surface. Towler’s machine had the Gnome engine which delivered less power, but it’s possible he used a non-standard propeller to ensure maximum rate of climb, whereas ours is the standard one which gives a rate of climb about half that quoted in the official figures. And while I don’t know Towler’s weight, I suspect it was a good deal less than my own 92kg!

Here’s the video. There are a couple of captions to show the point at which we reach 22kt, and the point 68ft after that, but it all happens a bit fast, so you’ll have to take my word for it that we reached 22kt after 17 turns of the wheel (120ft from the start) and the first liftoff occurred 43ft later, which is an eerily exact copy of the 46ft roll recorded by Towler. Unfortunately the wheels settled again and the second and final takeoff occurred 127ft after reaching 22kt. And of course 22kt is very much an estimate. If the windspeed 100 years ago was 15 knots instead of 10, we’d have been more than capable of matching Towler’s performance.

But following today’s trials, I’d be pretty confident of getting off the Vindex in similar conditions, which is very pleasing!

 

 

 

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2 Comments
  1. Jonathan permalink

    Your conservative estimate of a 10kt wind speed based upon the appearance of the waves could be a tad low, and its possible that up to 15kt was the reality. There are at least one or two clearly visible breaking crests in the photo, which would indicate something within the Force 4 range, also the photo was taken from a considerable height which would flatten the appearance of the waves. We also don’t know the strength or direction of tide at the time (or indeed whether there were any significant gusts at the moment of takeoff): if the wind was with the tide, then the effect would be to smoothen the crests, although this would also have the effect of reducing the ship’s speed over the ground.

    Too many variables perhaps, but nonetheless a huge achievement for Towler/Vindex and for yourselves!

    I’ve thoroughly enjoyed following your progress. Well done.

    • I agree – my estimate was on the low side, but at least I am now confident that faced with the same conditions on HMS Vindex I would have cleared the wavetops! I would be interested to know what calculations they did in the design stages. Did they assume worst case of flat calm, in which case the Vindex was supposed to be capable of 21kt?

      Anyway, thank you for your kind comments. It’s such a privilege to be a part of it.

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