Hi Dion,
How distracting to your flying ability in a crisis(Fire) do you think screen watching will be? A large proportion of Gas turbine aircraft operate with Overheat/Fire Warning which are used to prompt specified Engineered/Considered actions, designed to mitigate the condition and await for a specific response before proceeding with further actions. Overheat is just that, elevated temp warning, that if left could develop to a more serious fire condition. It is a prompt to go looking for the "Cause" of the symptom. I personally would be more interested in instrumentation that advised me of conditions that precipitate the formation of a "Fire Triangle" outside of combustion chambers, outside of normal operating baselines, such as: . Fuel Pressure Drop/Flow increase - Fuel Leak, and not really a good idea to stow away in a warming hole. . Engine Case/Exhaust temps (Case not combustion related) . Engine Performance . Oil System leaks in service . Etc. This level of awareness then is used to perform actions that break the triangle, minimise risk and not increase the situation. But this is all dependant on whether your trying to save your investment or your life. The worse point about being confident, is that if you're not right you have put the fire in the worse place structurally - Out in the wind you can control air flow - which relates to mixture, too lean and it goes out, crappy glide performance - but you could probably find somewhere to land in a reasonably structural machine. My 2c John From: [email protected] [mailto:[email protected]] On Behalf Of Dion Weston Sent: Tuesday, 22 January 2013 10:41 AM To: Discussion of issues relating to Soaring in Australia. Subject: Re: [Aus-soaring] FireWire fire detection wire. I and a number of other ASH25M owners in Aus have installed Safecraft systems in recent years. See: http://www.aircraftspruce.com/catalog/pspages/safecraft5.php These were shipped empty from the US. We engaged a specialist firm in Melbourne to re-charge them with Halon. For safety this system is cable operated by pulling a handle mounted on or near the instrument panel. Two separate metal discharge lines from the cylinder run the Halon to dispersant heads on the floor of the engine bay; one fore in the vicinity of the fuel injection area and one aft in the vicinity of the oil supply system. I'm reasonably confident that if the engine bay doors are closed the 3lb cylinder we have installed would have sufficient capacity to extinguish a substantive fire in this enclosed space. I am somewhat less confident of the fire extinguishing efficacy of the system if the power plant is erected and the engine bay doors are open. Hence the functionality of the system is fundamentally dependent upon early detection and action to properly shut the power plant down and retract it into the fuselage while it is still feasible to do so. The certified "detection" system installed in the aircraft during manufacture comprises a single bi-metal strip activated spot sensor embedded in the starboard side upper engine bay fire wall towards the front. It is inadequate to be relied upon. We have looked at installing a ring of linear heat detector cable of the type James has pointed to however the trick is working out placement and what level of ambient and alarm sensitivity to employ. Even then relying on an automatic system with so many variables in play seems fraught. I'm tending to the view of installing the fairly sensitive wire heat detector system to provide a heads up alert to the pilot and then resorting on a rear viewing infra red camera relaying an image of the power plant to a small screen in or near the instrument panel enabling an assessment of what may really be going on back there. Comments on this approach or thoughts on a better one anyone? Regards Dion On 12/01/2013, at 08:37 , Simon Hackett wrote: Noting that I've never seen it in real life, I must say that this appeals to me greatly on paper: http://www.aircraftspruce.com/catalog/pspages/active.php This is one step past a 'detection wire' - its a 'fire extinguishing hose': >From the web page: Active Extinguishing Line is totally independent fire extinguishing system from any power source. Its main secret lies in the heat detector in a form of a line made out of special laser predrilled polymer, which will react instantly to any source of heat or fire. This line (heat detector) is connected to reservoir containing fire-extinguishing agent: hexafluoropropane FE-36 or award winning Pyrocool FEF solution. Inside of the protected device (equipment) a loop made out of the heat detector breaks, creating a mini sprinkler, directly over source of fire or heat, extinguishing it instantly. In the moment of activation the system closed circuit switch collapses sending a signal informing of fire. Aircraft Spruce have sold it for years, and I doubt they'd keep selling it if it wasn't capable of doing what it promises. Regards, Simon On 10/01/2013, at 10:49 PM, James Dutschke <[email protected]> wrote: http://www.protectowire.com/products/protectowirelhd.htm It's essentially 2 insulated wires that run around an engine bay and touch when the plastic between them melts. Shorting and indicating the fire. Sent from my iPhone _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
_______________________________________________ Aus-soaring mailing list [email protected] To check or change subscription details, visit: http://lists.internode.on.net/mailman/listinfo/aus-soaring
