Another T-shirt design, this one based on a patent image.
Frank Whittle – a summary
Air Commodore Sir Frank Whittle (1907-1996) was a test pilot and flying instructor, but he is best remembered as a pioneer of jet aircraft. It was he who convinced the British government that the standard propeller engines had speed limitations (based on calculations made while writing his thesis) and that yes, he had a solution.
The problem was that conventional engines with hundreds of moving parts would inevitably fall apart when pushed beyond what was possible with contemporary materials. The solution was to reduce the power plant to a single moving part. He needed people to believe in his solution. He also needed money, which the government of early 1930’s Britain was reluctant to give him.

He co-founded Power Jets Ltd in 1936, a company which was able to exploit his 1930 patent for a turbojet engine with only one moving part. By the time the Second World War started, he had finally convinced the government that he had a usable and safe design. They bought the experimental engine from Power Jets and lent it back, allowing the company to continue until the company was nationalised in 1943.
All this effort took its toll on Sir Frank. Nervous exhaustion forced him to retire from the RAF in 1946, but not before a further jet propulsion system could be patented in his name. It is this that forms the basis of the new t-shirt design.
Discworld connection
The term ‘Whittle’ came up in the Discworld series. In “Guards! Guards!” we are introduced to Lady Sybill Ramkin, a wealthy resident of Ankh and enthusiastic breeder of swamp dragons (draco vulgaris). She used “whittle” as a term for disappointing dragons such as Goodboy Bindle Featherstone of Quirm (aka Errol), who would never amount to much. Short, stubby wings meant Errol would never fly and would therefore be incapable of mating.
Sam Vimes, Captain of The Watch, reflects on this dismissive adjective:
Total Whittle, Vimes thought… It sounded like whatever it was you had left when you had extracted everything of any value whatsoever. Like The Watch.
As it turns out, Sir Frank was something of a whittle himself. Standing five foot tall and with a small chest measurement, he failed the RAF medical (twice) when he applied. Luckily for him and for the development of the jet engine, he found a way in to the RAF. And it all came good for both Sir Frank and Errol – Sir Frank applied again and rose to be Air Commodore. Errol learned to fly and was last seen flying into the distance with a noble dragon (draco nobilis) which had terrorised the city.

It all ends well for Sam and the rest of the Night Watch. The men get a pay rise and a new dartboard, Sam finds love and companionship with Lady Sybill.
Whittle’s patent
All of this leads back to the landmark invention by Sir Frank, the jet engine. In 1946, he was granted US patent 2404334 for an aircraft propulsion unit – a jet engine. This wasn’t the first, and wasn’t the last, but it does have the big advantage from my point of view that it has a striking image to go with the patent.

T-shirt design
The patent image used started out as shown above. Using Inkscape, I could remove the background and be left with an image of just the text and drawings. Two things need to be done before I can put the design on a t-shirt. First, I need to choose the colour for the printing. Second, I need a fine scale render (high dots per inch (dpi) count) of the image. Inkscape can do both, so I got a 500 dpi image in white (which I won’t reproduce here).
I chose a dark blue t-shirt so that the image looks like an engineering drawing. Patents are not engineering drawings, but using blue adds a nice aesthetic to the design. Blueprints were so called because they were printed in white on Prussian Blue paper.
There is a useful website (colordesigner.io) which will give the Hex codes for any colour so that the correct colour can be programmed into a colour rendering app. Gelato, who I use as the print on demand supplier, also give the Hex codes for their t-shirts (or at least the T-shirts I’m using). There is also a colour comparator site so that you can see how close two colours are.

Am I going too far with this? Maybe, but it’s best to be correct about these things even if nobody notices.
The closest blue t shirt available was Gelato’s Navy Blue. I can’t tell the difference unless the colour are next to each other.
So, finally, I was able to put a white design on a blue t-shirt. Then it was a matter of getting some virtual models to do virtual cat-walks for me and upload everything to Etsy.

