shortfielder wrote:I am in the process of putting 175 wings on my 17o to gain the extra fuel capacity. I was told the 175 lift strut was a little stronger and a perfect fit. Does anyone know about this?
I also have an extra set of 175 fuel tanks in very good condition, cover skins, and electric fuel quantity gauges if anyone is interested.
Thanks Gary
HOO-BOY! (forgive me, Gary, but this is a good example to use on this subject)....
This is a great example of how things can seem very simple.... and a quick call/email to the Parts/MX guy will probably be a simple answer.... but actually takes up several hours of research to provide what the Member actually wasn't even serious about anyway! Whew!
Here's the answer: I don't know.
Here's why: The IPC (Illustrated Parts Catalog) for the 1956 thru 1962 Cessna 172 and 175 airplanes show TWO DIFFERENT PN's for those airplanes,... for EACH lift-strut, L or R,.... depending NOT on whether it's a 172 or 175...but whether it's an early (pre-mid-year '61) 172 or 175.
(C172's were made from 1956, but 175's were made from 1958... but both changed from early to later designs in mid 1961... then the moon changed phases in the middle of all that!)
Looking further into it... the individual item numbers do not demonstrate exactly what the difference might be! (It could be a simple change from the early Hi-shear rivets to the later AN426 rivets.... or it might be some other minor change, such as the fact that actual upper/lower attach fittings have different PN's (and that also might be simply due to a change from casting, to forging, to extrusion....
...)
...or is it due to some other fitment changeout...??
Then there's the fact that the 170-B uses a completely different PN for it's lift struts.... OH!... (and here's another frustration which might occur when a caller leaves the voice mail)... you didn't say WHICH model 170 you have.... nor did you say WHICH SERIAL you have.... etc etc.
See the problem? Even minor differences in production can make big problems for replacement parts. (While documenting why your airplane has 175 struts might be an even nuttier problem when some curious inspector notices....IF, he notices...IF it's even possible to make note visually of any difference.)
Even if you have all the various IPCs for all the various models... different PNs alone do not imply they are <or> are-not interchangeable...or adaptable to the other.
(All the IPCs do follow a similar convention, however: IF parts are indeed interchangeable, then comments in the IPC to the effect "use until supply is exhausted then use PN 1234567" or similar. If they are NOT interchangeable ...then different part nos are used. In this case, MULTIPLE part nos are used....implying your idea about swapping struts isn't something you should pursue.) None of which indicates anything regarding the anecdote you heard that "175 struts are stronger", which I think is probably B.S.
(This is written as I recall a Member who picked up a N.O.S. lift strut lying around in my hangar and installed it on his late B-model without much ado... but it looked good,... I mean, we didn't a have any PN on it at all and have no idea it's history but it was a lift-strut of SOME kind and certainly appeared really really the same as another 170B we saw nearby, and subsequently his airplane has won several awards at convention since.)
Anyway, there also is the issue of what happens when you change out only a SINGLE component ...such as a lift strut...which you think MIGHT be stronger.... Remember, a chain is only as strong as it's weakest link.... and the lift struts are not what usually fails when an in-flight catastrophic failure occurs.
I suggest you not complicate your life any more than necessary and keep your present struts.
