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Cowl Hinge Pin - Front Plate

StuBob

Well Known Member
My new-to-me RV-7 has the cowl hinge pins set up to pull out into the cabin. I’d like to flip that around and pull them out the front, and put covers there like most people have.

I’ve seen nice ones that are polished, some even engraved.

Any suggestions as to where to buy something like that already made? Any how-to suggestions to help this squeamish new owner start cutting fiberglass? :eek:

Thanks.
 
There are so many possibilities. The in the cabin method makes the cleanest look. So from the memory bank.

1) tab piano hinge wire van sells....
https://store.vansaircraft.com/cowl-hinge-stainless-steel-pin-right-cowl-hinge-pin-right.html

https://store.vansaircraft.com/cowl-hinge-stainless-steel-pin-left-cowl-hinge-pin-left.html

You would cut file a wider gap/opening between upper/lower cowl halves, just past the last forward lug in piano hinge. The gap is opened up half in upper and half in lower. This wider gap is small just enough the get wire/pin out. then you rivet a nut plate on the inside. A small screw secures the wire/pin with the flanged tab brazed on the wire/pin. This is by far the easiest. If painted the same color as plane and low profile screw it does not stick out.

[On my RV4 I built long ago I bent the wires/pin so it popped into the gap between cowls. but left a small part I could grab (with needle nose pliers). You grab it and flex it enough to clear cowl and pull pin out.]

2) Fancy sky is the limit in every variation of "plate", google it. It will lead you to builder sites. Plate can be flush or proud. The flush method requires fiberglass work. The proud version, say 0.032" can be beveled and engrave to your hearts content. Both typically use two nut plates, one in upper cowl & one lower cowl. This ties the two cowl halves together with the sheet metal plate, as well as keeping piano hinge pin from walking out into your prop.

3) Leave it alone. What you have works, leave it alone is my advice.
 
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Cowl hinge pins from Vans. Left & Right. Easy install, no fiberglass work/painting required. Just instal platenut for hinge pin screw. I’ve used these on three RV aircraft and they work great.

https://store.vansaircraft.com/cowl-hinge-stainless-steel-pin-right-cowl-hinge-pin-right.html

That works, or you can make a plate that simply covers the opening for the pins up front - it doesn't have to be flush/recessed. 0.032 aluminum or stainless doesn't create much of a bump, and you can rivet a nutplate or two inside the cowl so you can attach the plate with screws.

This is one of those areas where it is easy to obsess over a detail that is pretty minor in the big picture.
 
My new-to-me RV-7 has the cowl hinge pins set up to pull out into the cabin. I’d like to flip that around and pull them out the front, and put covers there like most people have.
I'm curious why?

I purposefully built mine such that they are removable from the rear (via the venturi vents, in my case). Reason being that a) it's a cleaner look from the front and b) there's zero risk of the thing coming loose and working its way into the prop. Which happened with a friend who got to buy a new prop as a result.

In fact it's always surprised me that given that possibility, Vans always stuck with the front entry method as standard.
 

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I'm curious why?

I purposefully built mine such that they are removable from the rear (via the venturi vents, in my case). Reason being that a) it's a cleaner look from the front and b) there's zero risk of the thing coming loose and working its way into the prop. Which happened with a friend who got to buy a new prop as a result.

In fact it's always surprised me that given that possibility, Vans always stuck with the front entry method as standard.

I did the same with my RV7. Mine weren't through the vents though.
Initially I doubted my wisdom as it was fiddly, but after doing it a few times I got better at it and worked out how to do it efficiently.
I did the same with the RV10 - which is actually even easier to do.

So my advice for the OP (if you've only done it once or twice) would be to give it a chance for a few cowl R&Rs and if you really don't like it then hack into your cowls :eek:
 
Not to re-direct this thread, but...

I access my hinge pins from inside the cockpit. They run thru a plastic conduit in each cowl cheekpiece and the pick-up the hinge halves on the cowl halves. The system is clean and easy to use, however, I find the pins periodically break (shear) at the point where the pin transitions from the cheek piece to the cowl. It's a pain to remove the section of pin left in the cowl. Has anyone else experienced this problem? And, more importantly, figured out how to prevent it?
 
Thanks for the replies.

As to the why?: the pins are dirty and make dark smudges on the upholstery. But more importantly, putting the top cowl on is now a 2-person job. The pins aren’t perfectly aligned, so there’s a certain amount of fiddling to do — push, jiggle, push, pull back, etc. It seems it would be a lot easier to push the pin with one hand and fine tune the alignment of the top, bottom, and pin with the other.
 
Thanks for the replies.

As to the why?: the pins are dirty and make dark smudges on the upholstery. But more importantly, putting the top cowl on is now a 2-person job. The pins aren’t perfectly aligned, so there’s a certain amount of fiddling to do — push, jiggle, push, pull back, etc. It seems it would be a lot easier to push the pin with one hand and fine tune the alignment of the top, bottom, and pin with the other.

Yep - care when doing pins into the cabin is required to have easy operation. There are some key elements to do to make this happen.

For me all three builds have side pins into the cockpit via 1/4" aluminum tubing acting as a guide. They slide into the cowl "like they were made for it".

Carl
 
Thanks for the replies.

As to the why?: the pins are dirty and make dark smudges on the upholstery. But more importantly, putting the top cowl on is now a 2-person job. The pins aren’t perfectly aligned, so there’s a certain amount of fiddling to do — push, jiggle, push, pull back, etc. It seems it would be a lot easier to push the pin with one hand and fine tune the alignment of the top, bottom, and pin with the other.

One other thing I forgot to mention:
I spin mine in with a small cordless drill. The end is ground to an offset rounded point as well. This helps with any misaligned eyelets as the pin spins. A little bit of LPS to lube and clean the pins at each removal.
Hope this helps
 
Thanks for the replies.

As to the why?

I get it. However see if you can improve the situation:
Wear rubber gloves
Pin fit gets looser over time with wear
Use a drop cloth in cockpit to avoid dirt
Improve fit/operation pin remove/install with guide tube
Does the pin have a point on it?​

Your desire to not deal with cockpit access to remove cowl is reasonable. "Van The Man" is a pretty great aircraft designer and engineer. Sage advice is build it PER THE PLANS.... often the better choice, lighter, less expensive, simpler to build and maintain However owner's, either the original builders or secondary owners tend to want to add their own custom touches.

The main reason to go inside the cabin is a SMOOTH look. Is it worth it? No not for me, but as other stated they would not do it any other way.

Others LOVE using 1/4 turn lock fasters. They add weight, cost and does not have the smooth hidden look. However they work also.

Some have used piano hinges to hold on wing tip fairing. It looks nice. Is it better than blind rivets or screw and nut plate? Beauty is in the eyes of the beholder. I like SS flush screws and nut plates. Although rivets are fine if you don't mind drilling them out in the event you need to remove fairing. In 10 yrs of flying my first RV the wing tip fairings never came off. NAV & Landing lights were accessible from outside. Cowl obviously needs to come off at least every 25 hours.

TWO MAN JOB - I can and have removed and reinstalled my cowl solo 1000 times (99.9%) but having two people makes it easier and more fun. One person is awkward even with cowl pins all from outside cockpit.

It is your plane. If you want to convert it can be done. Up to you. HOWEVER if the pin is hard to get in from cabin side it may still be hard to get in from the Prop side if the hinge is not aligned. No debate pin coming out Fwd towards prop is easier. If your cowl is painted then careful work is needed, yet may still require a touchup and might not be perfect.

In this case FAR's do not prohibit you from making Mod. It does not affect the performance or significant systems (please read the FAR's to see what you can and can't do). EAB plane is not a total blank check to do whatever, even if the original builder. Some Mods require A/C going back into Phase 1.
 
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I like front install for hinge pins. I made some nice hinge pin covers from cheap SS tablespoons from Dollar Tree. Cut off the handle, sanded to a nice tear drop contour, then drilled and countersink for an 8-32 screw. Polished when done on the buffer.
 
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