Wing Mounting

Wing Mounting

Posted: Thu Nov 02, 2023 12:28 am

by Skippydiesel

As part of the recommended method of attaching the wings to the fuselage, Sonex recommend the application of WD 40 to the wing spar.

WD 40 is not particularly good lubricant - some would argue not a lubricant at all, rather being a water (W) dispersant (D) fluid.

So what is the actual purpose of the WD 40 application ?

Depending on your opining/advice above - what alternatives/better products would you recommend?


Re: Wing Mounting

Posted: Thu Nov 02, 2023 9:22 am

by kmacht

The WD-40 helps the spars slide past each other in the tight fit spar tunnel. It isn’t necessary but does help. You don’t want something thick like oil or grease that’s going to stay and collect grime and dirt between the spars over time. I’m guessing that wd-40 was called out because it evaporates quickly, is cheap, won’t hurt aluminum, and is widely available. There are probably better products but WD-40 does the job and won’t get them tech callas asking what other less readily available products are or where to buy them. It’s just a temporary lubricant to get the spars to slide past each other. It serves no other purpose once assembled so use whatever you think is best.


Re: Wing Mounting

Posted: Thu Nov 02, 2023 10:00 am

by Arjay

My understanding is that WD40 is a penetrating oil.


Re: Wing Mounting

Posted: Thu Nov 02, 2023 5:53 pm

by Skippydiesel

Arjay wrote:My understanding is that WD40 is a penetrating oil.

Thanks Arjay,

WD stands for Water Dispersant - In addition to its original fluid, WD40 now has a large range of, mainly, lubricants under the WD40 brand.

Check with Wikipedia - but I think the original fluid may have been developed for military use. Other uses were then found eg penetrating oil


Re: Wing Mounting

Posted: Thu Nov 02, 2023 10:08 pm

by karmarepair

I used silicone spray on the spars themselves, and the ends of the tunnels where the mounting blocks are. It’s a better lubricant than WD-40. I used Redline Assembly lube on the PINS that I used instead of bolts.

The WD-40 story is fascinating, this is the fullest version I’ve seen http://www.todayifoundout.com/index.php … ted-wd-40/


Re: Wing Mounting

Posted: Thu Nov 02, 2023 11:46 pm

by Skippydiesel

FY! - Sonex tell me that the advice to use WD 40 on the wing spars, to aid wing attach is ancient history & will be removed (now that I have asked about it)- no lube is required on the spar, lithium grease (or similar) may aid the fitting of the spar pins.


Re: Wing Mounting

Posted: Thu Nov 02, 2023 11:59 pm

by Skippydiesel

karmarepair wrote:
The WD-40 story is fascinating, this is the fullest version I’ve seen http://www.todayifoundout.com/index.php … ted-wd-40/

WD 40 history/present day - Interesting but somewhat lacking. Here in Australia WD 40 original, is available in liquid form (as well as aerosol) which I much prefer, usually purchasing in 5L container & decanting as needed into a squirt bottle. It may be my imagination however the liquid seems to be a more viscus product than the aerosol.

Further WD 40 had become a brand name for a whole range of materials eg WD 40 spray lithium grease, silicon’s, gardening tool cleaner/lubricator, PTFE dry lub, etc etc.

In general I find most of the WD 40 spray products to be of inferior quality compared with many other products of similar/same name.

Guys,

I have a question regarding wing pins, the previous builder along with the big main pins and the secondary pins decided to drill three 1/4” holes evenly spaced two outer ones are towards the bottom and middle one is towards the top. They had bolts with nylocknuts on them and were a pain in the butt to take out. My question is,what impact do the holes have on the spars? Would the extra bolts make them to ridged? Fill with jbweld? Start a separate topic?

Thanks

Greg

A picture would help. There are no secondary pins. Ultimately this may be a question for Sonex tech support. JB Weld - no way.

Hi Greg,

I just want to confirm, are you talking about the alignment holes depicted below? Or different holes?

There’s a reason why you don’t put bolts in the alignment holes. They are just 1/4” holes, and the material thickness is not very much. The amount of movement the wing structure likely sees as you approach limit load will likely cause damage around those holes. The bolts are really strong, but look at the structure where the main pins go. There is a lot of bearing area between the 3/8” bolt and the aluminum. The 3 holes that Evan circled above won’t have much meat and for high loading the stresses on the aluminum spar will be really high.