Cowl hinge pin approach/ideas?

[Freemasm]

Started a discussion here about hinge stock sourcing

VAF post

Placing the top cowl, there is a lot of movement with the 090 pins. I wanted something more finite fit for the cowl placement/mating hinge installation. I reduced some stainless steel 1/8 down to 0100 at the insertion end to 0120 at the tail. It holds it very snug.

I’m liking the fit. Any reason not to use the above for flight? Can’t think of one.

Your informed opinions would be appreciated. Thanks.

 

[Stevea]

Yes, there will be movement with the .090 pins installed in those hinges. It will also show itself in flight, when the upper cowl is pressurized from the incoming cooling air....I've seen this from the front seat of a friends -8A. It's not big enough to cause air leakage out the back of the cowl....but this is an RV, and we're trying to hold ourselves to what looks good from 1 foot distance, not 10-20 feet.

I installed larger diameter stainless pins that were much closer to the 1/8" nominal hinge loop ID. I think they are about 0.120" dia......but don't quote me on that (too long ago to remember .....can measure it next time at the hangar if you like). They are the standard Van's design length and location for a 6/6A...ie: inserted/removed through the oil door. It started out as one of those "I wonder if this will work?" kind of things. But in about one afternoon of bending to shape and tapering the tips (mostly on the long pin from the oil door toward the left cowling side), the pins went in without any issues. I did have to give up about the last (outboard) 2 inches of pin length where the wrap around the firewall is the tightest radius. But....that "un-pinned" length is still held tight by the (now larger diameter) top cowl pin, the bottom cowl side pin to the firewall, and the side seam pin between top and bottom cowls.

Normal installation today is to wipe the pins clean and apply about 4 drops of liquid Boelube smeared over the length of the pin. They go in fairly easily. Should also mention, there is a 180 degree bend at the oil door end, to act as a finger pull loop during removal.

 

[D-Dubya]

Which hinge? The one that mates the top of the cowling to the fuselage and has to curve around, or the ones that mate the top and bottom halves together?

If it's the former, and you're worried about fit & appearance, have you thought about quarter-turn fasteners in lieu of the hinge? Yeah, they're a little pricey, but you don't have to reach your hand up into a hot engine compartment to get the top off. They hold as tight as you want them to as well.

 

[JonJay]

Yeah, they're a little pricey, but you don't have to reach your hand up into a hot engine compartment to get the top off.

That part of the engine compartment isn’t that hot. If it is, you have a problem.

For the top hinge, you can use a pin of the correct size that fits the hinge and then taper down the last 6-8” so it goes easily around the bend. Chuck up the pin in a drill and taper the pin with a disk sander while the drill is spinning the pin.

Screws, quarter turns, hinge pins, are simply personal preference. They all have advantages and disadvantages. I personally like the cleaner look of the hinge pins as Vans designed.

 

[Freemasm]

So what I'm hearing is, my modified 1/8 pins are good for flight it seems.

Surprising how much easier threading the eyelets is with a pin that more closely matches their ID. I'm also hoping that this will help assure more equal loading of the eyelets making them less prone to breakage.

BTW, I'm utilizing a small access door a la the 14, maybe others.

Once again, any experience/validation of "near size" pins would be appreciated.

 

[mack55]

Started a discussion here about hinge stock sourcing

VAF post

Placing the top cowl, there is a lot of movement with the 090 pins. I wanted something more finite fit for the cowl placement/mating hinge installation. I reduced some stainless steel 1/8 down to 0100 at the insertion end to 0120 at the tail. It holds it very snug.

I’m liking the fit. Any reason not to use the above for flight? Can’t think of one.

Your informed opinions would be appreciated. Thanks.

Where did you buy the stainless pin? Not sure I will have enough that comes from Vans..

 

[Freemasm]

Where did you buy the stainless pin? Not sure I will have enough that comes from Vans..

McMaster Carr

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

 

[HFS]

Do a search for "Drill Rod" & look at Post #3 ...

HFS

YMMV - but this has worked for me for 34 years and counting.

 

[HFS]

McMaster Carr

McMaster-Carr

McMaster-Carr is the complete source for your plant with over 595,000 products. 98% of products ordered ship from stock and deliver same or next day.

www.mcmaster.com

I buy from McMaster-Carr all the time (and have for 35 years), and my customer number with them is 263,716,300! Imagine having a customer base where one of the numbers is over 263 million! There is a reason for that ...

HFS

 

[Freemasm]

Drift but hey,

Truly great service and selection from them. If the customer numbers are truly sequential, then wow. I’ve had mine for a while now.