pudestcon Posted October 12, 2010 Posted October 12, 2010 G'day, I have a bent ss strut bracket that connects the strut to the trailing edge spar. I want to know your opinion on whether this bracket can be straightened and put back into service or if it should be discarded and new ones manufactured. Please refer to the photos attached here. Thanks in advance, Pud
facthunter Posted October 12, 2010 Posted October 12, 2010 repair or renew? It is a gradual bend and there are no cracks. I cannot see why you would be better off making a new one if you straighten it carefully and check for cracks afterwards. I know a front one has failed so check with someone who can assurre you. (Daffyd Llewellyn?). Nev
pudestcon Posted October 12, 2010 Author Posted October 12, 2010 It is a gradual bend and there are no cracks. I cannot see why you would be better off making a new one if you straighten it carefully and check for cracks afterwards. I know a front one has failed so check with someone who can assurre you. (Daffyd Llewellyn?). Nev Yeh, I take your point Nev and that is what I'm inclined to do but my hesitation is because of AN 4-99, which states in part that the ss bracket lug "can be bent and should not be bent back". I'll keep you informed of what I find out. Pud
Blueadventures Posted October 12, 2010 Posted October 12, 2010 Hi Stainless Steel work hardens; so I'd replace the item. Cheers
pudestcon Posted October 12, 2010 Author Posted October 12, 2010 Hi Stainless Steel work hardens; so I'd replace the item.Cheers So looking at the photo showing the extent of the bend Blueadventures, would you say there would be significant work hardening, or at least enough to be concerned about, if I was to straighten it? Pud
Riley Posted October 12, 2010 Posted October 12, 2010 Pud With all due respect to learned formites here-in, we're talking about a Thruster here - not an F-18. Despite the characteristics of stainless, straightening that minimal degree of bend is not likely to create a potentially catastrophic failure situation. Doctrine (and common sense) requires close inspection of these brackets for cracking at each pre-flight anyway but if it remains a concern, include a die penetrant test with your 50 hourlies. Any breakdown in the integrity of these brackets will visible in the lead up long before the point of separation is reached. cheers
pudestcon Posted October 13, 2010 Author Posted October 13, 2010 PudWith all due respect to learned formites here-in, we're talking about a Thruster here - not an F-18. Despite the characteristics of stainless, straightening that minimal degree of bend is not likely to create a potentially catastrophic failure situation. Doctrine (and common sense) requires close inspection of these brackets for cracking at each pre-flight anyway but if it remains a concern, include a die penetrant test with your 50 hourlies. Any breakdown in the integrity of these brackets will visible in the lead up long before the point of separation is reached. cheers I'm inclined to go with your suggestion Riley, but I have ordered 2 new brackets though - cost$55 each inclusive of GST. Sounds expensive until you realise there is probably close to an hours work in each one maybe. I'm interested in the die penetrant test; can you do that yourself or is it something you would have an expert do? What about having the bracket xrayed - would this work on stainless steel? Pud
Skyhog Posted October 15, 2010 Posted October 15, 2010 The front one that failed had been straightened (possibly more than once). Good to see you got new ones made Pud. Cheers.
billwoodmason Posted October 15, 2010 Posted October 15, 2010 Pud, A few years back a person I know was fatally injured in a thruster which had a strut attachment failure due to straightening bent brackets - which weakened and changed the radius of the bend. Throw the bent bracket(s) away and save your family the grief. Cheap insurance I reckon !!. Cheers, billwoodmason
Blueadventures Posted October 15, 2010 Posted October 15, 2010 I'm glad to hear you have replaced the item as strainhtening is not an option. The recent replies fully re-inforce your decision. Cheers and good flights.
pudestcon Posted October 19, 2010 Author Posted October 19, 2010 Thanks everybody for your thoughts and observations, and views on the subject. I took delivery of the 2 new ss brackets today and they are a perfect replica (without the bend:laugh:) of the existing bracket so should fit seamlessly onto the spar. They will be fitted in the next week or so. If anyone needs a stainless steel fabrication company in WA then go here Stainless Steel Sheet Metal Fabrication Perth Western Australia Cheers, Pud
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