Our club used to have two IS28 trainers about 20 years ago, I can well remember doing this wing resonance test on one of them only to find exactly what you described and then discover that the cones were not done up tightly enough! The aircraft had been flown like this for some time I believe.
I often as part of the DI still do a brief wing oscillation to make sure all is tight and also listen for loose components in the wings and observe the undercarriage suspension. I believe it's also worthwhile for wooden/fabric wings to look for damaged ribs etc. John Parncutt Melbourne Gliding Club. -----Original Message----- From: Aus-soaring [mailto:[email protected]] On Behalf Of [email protected] Sent: Wednesday, 2 December 2015 2:59 PM To: Discussion of issues relating to Soaring in Australia. Subject: Re: [Aus-soaring] Wing frequency Procedure The test if done properly can also pick up loose/worn wing root bearings and for long wing multi panel wings ( think nimbus) worn bushes. some undercarriage faults will also show up. in worst case you can hear the clunk of the loose bits. for the old IS28 if the centre wing joining cones were not tight the wing shake would show it up as not only did the frequency change but from the tip you could see independant movement of each panel and the fin. more like a shudder than a smooth flex of the wing. Peter Heath Not current long wings pilot. ---- Mark Newton <[email protected]> wrote: ============= On 1 Dec 2015, at 9:42 PM, Justin Couch <[email protected]> wrote: > There is also one case where it didn't (Bathurst's DG300 that delaminated the > spar caps from the wing didn't pick up a freq change, but the tap test did). Interesting - I’ve spoken to Brits who had never heard of the tap test and were a bit bemused at Australia’s seeming obsession with it when they found out about it. Nice to know that it might be useful for something :-) - mark _______________________________________________ Aus-soaring mailing list [email protected] http://lists.base64.com.au/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list [email protected] http://lists.base64.com.au/listinfo/aus-soaring _______________________________________________ Aus-soaring mailing list [email protected] http://lists.base64.com.au/listinfo/aus-soaring
