Re: landing gear/gearbox information
Posted: Tue Feb 27, 2018 8:13 pm
I find it interesting that Cessna went from an NAS147-34 bolt at the inboard end of the gear on the '48 to using a weaker AN7-20A on the later models.
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Do you think the NAS147 bolt is strong enough to perform the same function as a Pponk, that is, to cause the gearbox to tear apart in a groundloop? That's the only reason I can think of that they'd change the bolt out just to have a weaker one. But with only one year of production in the books, could they really have gotten enough field experience? Or that they'd even care? More likely the AN7 was cheaper and more available.n2582d wrote:I find it interesting that Cessna went from an NAS147-34 bolt at the inboard end of the gear on the '48 to using a weaker AN7-20A on the later models.
It was an AN 365. Real crusty lookingn2582d wrote:I see that the NAS 147 bolt is a carryover from the C-140. There the landing gear attach structure is welded steel rather than aluminum castings. I have no idea but perhaps the yield strength of the NAS bolt was more compatible with that steel attach structure and later, on the the 170A, Cessna decided it was overkill (or needlessly expensive) to continue the use a NAS bolt there??? It really would be interesting to test what yields first with the various combinations of bolts and nuts at the inboard gear attach point.
Edit: Jim, were were typing at the same time. You kind of answered my question with your response. Do you know what style nut - AN363 or AN365 - was on the AN7 bolt?