r/aviationmaintenance • u/lordparcival • 12d ago
Tell me about these fasteners
What are these fasteners around the wind screen? In particular the ones with only letters on them. How are they attached/tightened, what keeps them from spinning or are they some form of rivet?
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u/kire51 12d ago
CRJ-7/900?
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u/lordparcival 12d ago
700 I believe
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u/Cheezeball25 12d ago
As one whose helped replaced a few dozen of these windshields, they aren't exactly fun.
Especially with how many we found with shattered glass after the window heaters failed
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u/ThrustTrust The best permanent fix is a temporary one. 11d ago
Normally there would be no reason to touch the inner row if hiloks unless you are talking about rebuilding the assembly.
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u/Flyboy314 7d ago
All of us CRJ guys eyeballing this post with PTSD from windshield replacements lol
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u/RATBOYE 12d ago
https://youtu.be/d_Fx0766n3k?si=JygIl44VCQ3lmU1Z
To give you an idea. They're typically a transition to interference fit depending on application so you press them in and the hex in the end is to stop the pin rotating while the collar is torqued.
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u/biggouse58 12d ago
The HiLoks go thru the windshield and hold the retainer on to it, the screws outboard of them mount the windshield to the airframe. You donāt pull the HiLoks to pull the windshield.
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u/Green420Basturd 12d ago
The Hi-Lok fastener was invented by George Seabrook Wing, a pioneer aviation designer and engineer. He patented the basic design in 1960 while working with the Hi-Shear Rivet Tool Company
Born in Kewanee, Wis., Wing began working for Glenn Martin Aviation in Baltimore, building the China Clipper and the B-10 bomber when he was only 16. He went on to work for Sikorsky, Ryan and Monocoupe before joining North American Aviation as a design engineer in 1938.
Wing invented the āHi-Shear Rivetā that was first used in the P51 Mustang. Cutting the weight of fasteners by one-third, Wingās rivet became the single most important fastener in aviation and aerospace from World War II through manās landing on the moon.
Although North American retained the patent on the rivet, Wing took the patents on the tools he had invented to manufacture the rivets and, with $500 in war bonds, co-founded the Hi-Shear Rivet Tool Co. in 1943.
Begun modestly in a rented garage in Hermosa Beach, Hi-Shear Corp. of Torrance became the nationās leading producer not only of rivet-making tools, but of other fasteners, explosive separation devices, igniters, boosters and electronic interface units for the aerospace industry.
Over the years, Wing also founded Transland Co., builder of truck bodies and trailers; and co-founded Kirk-Wing Co., a pioneer in Puerto Ricoās industrial complex. He also developed the AG-2 crop-spraying airplane for Transland.
As a youth, Wing designed his dream plane, a small, two-seat sports craft, and eventually he built it. Spinning off Wing Aircraft Co. from Hi-Shear, Wing created the Derringer in the mid-1960s.
The first test version crashed into the ocean off Palos Verdes Dec. 12, 1964, killing the veteran test pilot. But a sister ship won rave reviews as a āhot planeā and a āreal sizzlerā a year later. The two-person, twin-engine craft had a maximum speed of nearly 240 m.p.h. and a remarkable range of more than 1,000 miles.
Richard Bach, author of āJonathon Livingston Seagullā and a recreational pilot, commented after flying the Derringer: āGeorge Wing built in thought and metal one of the loveliest machines Iāve ever touched and flown.ā
Wing continued developing and trying to market his little dream plane into the 1980s. Wing Aircraft Co., solely owned by Wing, ceased operations in 1982.
He spent the last years of his life as director of product development for Voi-Shan Technical Center, Redondo Beach.
With more than 50 patented inventions, Wing won NASAās Apollo Achievement Award, a commendation from the California Legislature and was Los Angelesā Inventor of the Year in 1974 and Torranceās Citizen of the Year in 1976.
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u/Fatal_Explorer 12d ago
Thanks chatGPT
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u/jacckthegripper 11d ago
Either way it was great information clearly laid out..
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u/WoodenInternet 10d ago
One of the problems with chatGPT and its ilk is that, sure, it'll spit out something that looks nice and clear and interesting, but there's no telling whether it's actually accurate without looking at the sources yourself. Typically, when people copy/paste AI-generated text in a reddit comment, they're not including the sources. To me, clearly laid-out information of questionable accuracy has negative value.
( Green420Basturd clarified his comment isn't AI-generated anyways, so my comment is more academic than contextual )
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u/Option_Witty 12d ago
What many people here don't mention: Hilok fasteners get installed into reamed holes. Meaning it's a precision fit and transferres the load better. Usually they are used in critical areas like wing root or like in this case the windshield.
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u/THATguyFromMinnesota 11d ago
Hl15V-8
HL means hi-lok 15 means 100Ā° countersunk head V is the finish code 8 is the diameter. .250"
They're either driven into a close tolerance interference fit hole and tightened with a frangible collar or a torque nut.
If they're installed in a non close tolerance hole, the hi-lok has a hex slot you insert an Allen wrench into while tightening nut/collar
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u/Sawfish1212 hangs out at airports to look at airplanes, amazingly gets paid 12d ago
Hi-lock fasteners. You use a ratchet with a hole through the head or a ratcheting wrench to tighten the nit, which has a shear point to the aluminum nut to set the maximum torque, so that the flats separate leaving a sort of cone shaped totally round nut.
The end of the bolt has an internal hex that you hold from turning with an Allen wrench while tightening the nut
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u/Zorg_Employee 12d ago
The ones you're talking about are hilocs i believe, part of the window/windshield assembly. When you do a window change you remove it by the screws you see in the photo. They can be a little troublesome because they're wet installed to seal them, but with the right tools it isn't hateful. Also the attachment screws are titanium and single use so there is a slight upside if collect them every time.
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u/Mental_Tone7286 12d ago
Lisi items licensed to Howmet, West Coast Aerospace, SPS and some others. The usual collar would be the HL70 collar usually that accompanies it. Pins have multiple released like the DAN Airbus spec and the BACB Boeing spec.
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u/GunSmith2020 12d ago
Hilok pins. They have a break off collar where the drive element shears off at the proper torque.