The bombardier beetle uses its rear-end ‘cannon’ to fire a high-pressure jet of boiling irritating liquid at an attacking predator. It is much more sophisticated than an army cannon, though, as the bombardier beetle fires its explosive discharges at around 500 pulses per second!1,2
The mechanism is highly complex, but put simply, the bombardier rapidly mixes two chemicals (hydrogen peroxide and hydroquinone) and injects them into a heart-shaped combustion chamber which contains mainly water.3 The beetle then injects a third chemical (catalase) which greatly speeds up the normally mild reaction to explosive force. The jet of mainly water/steam fires repeatedly out through nozzles at a stunning 20 metres (65 ft) per second.
Now it seems that the bombardier’s explosive secrets could inspire engineers to design better aircraft engines.4 The process is similar to the pulse combustion technique that powered Germany’s V1 flying bombs during World War II. The bombardier beetle attains far greater pulse efficiency, though. How? ‘It’s become evident that the dimensions of the chamber and the nozzle coming out of the back are crucial’, Andy McIntosh, professor of Thermodynamics and Combustion Theory at the University of Leeds, told New Scientist.4
In mimicking the bombardier’s remarkable combustion mechanism, Professor McIntosh hopes that the high ejection efficiency of the 1 mm (0.04 inch) beetle combustion chamber can be scaled up for reigniters in aircraft engines. (These small devices shoot charged chemicals into the engine if it stops at high altitude.) But the beetle’s unique combustion process cannot be duplicated merely by copying the dimensions of the bombardier’s explosion chamber: ‘In reality the combustion involved is complicated by the catalytic processes associated with the muscle lining of the chamber.’5
Nevertheless, Professor McIntosh believes that the lessons learnt by studying the bombardier beetle’s secrets could lead to innovative design breakthroughs, with such novel ignition devices.6 Earlier researchers1 found that the beetle precisely times the opening and closing of the inlet valve to its combustion chamber to avoid blowing itself up. It also seems to be able to control the pressure and direction of the resulting jet with pinpoint accuracy—at a bird, frog or other predator.
It just goes to show that all the intricate machinery that God has designed in nature is far more complicated than man’s—a fact Professor McIntosh, with many years of engineering research experience, readily acknowledges. ‘They can even repair and reproduce themselves’, he says.7 ‘So how much more do they declare “his eternal power and divine nature” (Romans 1:20)!’
Re-posted on homepage: 1 April 2015
References and notes
- Dean, J., Aneshansley, D.J., Edgerton, H.E. and Eisner, T., Defensive spray of the Bombardier Beetle: a biological pulse jet, Science 248(4960):1219–1221, 1990. Return to text
- Armitage, M.H. and Mullisen, L., Preliminary observations of the pygidial gland of the Bombardier Beetle, Brachinus sp., J. Creation 17(1):95–102, 2003. Return to text
- The reaction is C6H4(OH)2 + H2O2 → C6H4O2 (quinone) + 2H2O, producing a boiling water solution of quinones. This is hotter than 100ºC, because of the dissolved substances and higher pressure. Return to text
- Knight, W., Beetle’s jet may inspire new engines, newscientist.com, 24 December 2003. Return to text
- Engineering and Physical Sciences Research Council, Beetle jet—studying a species of beetle could lead to advances in combustion, EPSRC Newsline, Summer 2003, p. 02. Return to text
- The UK’s Engineering and Physical Sciences Research Council has given a three-year research grant to Professor McIntosh to fund the numerical modelling of the bombardier beetle’s combustion device, and to investigate possible biomimetic applications (whereby one ‘copies’ designs in nature for useful engineering purposes). Return to text
- McIntosh, A., 100 years of airplanes—but these weren’t the first flying machines!, Creation 26(1):44–48, 2003; creation.com/airplanes. Return to text