Pyroalliance quiz answers

Q/ Compared to the train (5 hours) or the plane (1 hour), the travel of a pyrotechnic order along a detonating cord between our two sites of Les Mureaux and Toulon would typically take:

(Roughly 2 minutes)
A key feature of pyrotechnics is SPEED. Detonating Cords are used to transfer a pyrotechnic signal, for instance to propagate the ignition order of the solid rocket motor of a missile. The detonating signal travels at approximately 7000m/s!

Q/ Deploying with a battery the same power than a pyrotechnic cartridge would require:

(Roughly 10x more mass)
A key feature of pyrotechnics is ENERGETIC DENSITY. Pyrotechnics offers indeed an advantageous solution when used to motorize actuators like those used on cruise missiles to deploy their wings. One of the main benefits is related to the incredible density offered by energetic materials compared to electrical batteries which weight would severely harm the reachable range of a missile.

Q/ Reliability enabled by pyrotechnic solutions can reach up to:

(1 – 1×10^-6 /meaning a failure will occur less than once every 1.000.000 occurrences)
A key feature of pyrotechnics is RELIABILITY. Because embarked on critical missions, pyrotechnic solutions used on military systems have indeed to comply with very high standards of reliability. As an example, Flight Termination Systems are embarked on missiles which are fired on military test ranges, typically in the frame of the testing and qualification process of the related missiles. Their function is to terminate the flight and protect the test range as well as the populated areas in case the missile dangerously deviates from its nominal trajectory. Their reliability is therefore one of their key design requirements!

Q/ Which of the following explosives is the most adapted to high temperatures?

(Hexanitrostilbene – also called HNS)
A key feature of pyrotechnics is ROBUSTNESS TO THE ENVIRONMENT. Pyrotechnic products are indeed used in extremely severe environmental conditions, whether in hostile regions on earth, in the air or even in space. Such operational contexts go with possibly extreme temperatures and their range of use is therefore as large as possible. Compared to HMX and RDX, HNS has the best performance bearing very high temperatures. Pyroalliance has therefore developed mild detonating cords based on this explosive.

Q/ Many pyrotechnic devices are embarked on a tactical missiles to fulfil a large variety of functions. They are typically designed to secure an availability during:

(>12 years )
A key feature of pyrotechnics is AVAILABILITY Pyrotechnic products are embedded in military systems which can be stored for years before being deployed on military operations. Still, when deployed, their reliability must be preserved and granted at the original level it had out of the factory. This “Fit and Forget” feature is highly valuable on systems which lifecycle possibly involves several sequences of storage and traveling before use.  Fuel System Valves, for example, are typically designed to secure that availability. The function of the One-way fuel valve – Normally Closed- is to ensure the tightness of the fuel tank until activation.

Q/ To secure electrically initiated pyrotechnic chains, the typical NATO Standard require that when subjected to a 1A minimum current with an associated power of 1W minimum, such chains shall not fire within at least:

(5 minutes)
A key feature of pyrotechnics is SAFETY. So-called 1A/1W initiators and detonators implemented to trigger most of the electro-pyrotechnic chains have to comply with a NATO standard (STANAG) that involves a safety design constraint. On top of a Safe & Arm device placed upstream, their design grants a non-fire current of 1A and prevents from any accidental start that could for instance be caused by a lightning bolt. Typically the general principle of a cable or rod cutter is that an electric current (typically 5A during at least 10ms) will fire a 1A/1W initiator under defined emergency circumstances.

Q/ Please tick the following assertions which you believe are true:

(All those assertions can indeed be true!

• Pyrotechnic products do not necessarily generate external effects
• Pyrotechnic products can be out-of-pyro class
• Pyrotechnic products are subject to and resist to significant shocks
• Pyrotechnic products do not necessarily induce significant shocks when activated)

A surprising feature of pyrotechnics is the ability to be harmless when this is the desired effect (obviously the function of some pyrotechnic products is to generate on purpose external effects when their function is to cut or severe a structure). A typical product which ticks all boxes above is the pyrotechnic separation nut which can bear more than 10.000G whereas it will have no external effect and induce as little shock as 500G on its environment (as soft as non-pyrotechnic equipment). Besides it can be classified “out-of-pyro class” just as airbags for the automotive.