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Tip: Show us your cowl / hinge pin cover or method to secure pin

FlyingArcher

Well Known Member
Hello RVers,

I need some help trying to find out a link to a series of pictures I've seen some time ago, showing how different builders had solved the problem of securing the cowl hinge pin. I think the pictures were taken at some fly-in, but I can't relocate the page, even after googling with different keywords.
Maybe the author of this page will read this...

Thanks a lot
 
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Not for a VAN's

Sorry I didn't mention that at first, but my question is not for a problem I'm trying to fix on my -9A project, but for another one where I'm part of a builders team for a Jabiru J400.
The top and low cowls are joined with a hinge, like on standard VAN's cowls, and I'm trying to bring some examples of how to secure the hinge pin to my teammates.
I'm far far away from reaching that step on my -9A :)
 
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Here's Mine!

Paint02.jpg
 
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Hinge Pin retainer pictures from my buddy Rick Gray's award winning RV-6 :p Rosie

hinge_retainer01.jpg


hinge_retainer02.jpg


hinge_retainer03.jpg


hinge_retainer04.jpg
 
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Hinge Pins

I could send you a picture of mine but you wouldn't see the cowl hing pin tab!

My cowl pins are inserted from inside the fuselage.

A short piece of 3/16" stainless brake line is inserted though a small hole in the firewall that is aligned with the hinge and extends into the cabin. The line acts as a guide for the pin and is epoxied in place in the firewall and a clamp holds the other end in place in the cabin.

The pin is inserted from the cabin, through the brake line and then into the hinges. A little pushing and twisting on a plastic knob that is epoxied on the end of the pin allows it to slide right through the hinges and into place.

Extra care is needed when the hinges are attached to the cowling to ensure the hinges don't bind later. Grind the pin end to a dull point so that it slides into the hinge more easily.

I had heard from other builders that this technique would require two people to install the cowling (one to position it in place and the other to install the pin from inside the cabin). Not so...... If care is taken during the installation of the hinges, installation or removal of the cowling top is a one-person task.

Keith

N355RV
RV9A

10 months flying......
 
Mine are hidden but differently

Mine are inserted from the aft edge by pulling out the sides a little. There's a right angle bend in each one at the back end. When they are fully inserted I close up the rest of the cowl along the firewall with skybolt style fasteners. I did not want a hole in the firewall, so this is all done externally. The bent leg clears the camlock but is stopped by it so it cannot work back and thus below the flange. Removal is accomplished with a wire loop on a bolt shank. Pics and details on request. I don't think it's any different, but it's a SJ cowl.
 
Thank you!

Thanks a lot for all your answers. I just had a message form our builders team leader, and after reading many comments on this forum, it seems that we'll go for Camlocs ;)

I think this is the way I'll also choose when it's time for me to work on that part of the project.

For now, I've just played with the tools by building the RV Training Project and the nice Toolbox, waiting for a replacement for some empennage parts that have been damaged during transportation to France :eek:

At least I could buck my first bad rivets on test metal...

Cheers
 
Cowl/Firewall Hinge Pin Retention

Is it necessary to, and if so how do you retain the hinge pins on the cowl to firewall joints?
Jim Sharkey
 
I stole this idea...here's how I did the top cowl to firewall pins:
20031110_hinge_pin_clip.jpg

20031110_clip_closeup.jpg


And here's how I did the lower cowl to firewall pins:
20031030_hinge_retainer2.jpg


Might be hard to visualize that last one, but basically I bent about 4" arms on the tops of the pins, and the arms tuck under those little clips along the cowl hinge.

Nothing moves anywhere that way.
 
Top Cowl Hinge pin retention

While I was at OSH this year, one of the things I paid particular attention to was the solution various builders used to retain the cowl hinge pin.

Here are some examples:


For those that are using/have used the stock hinges, any additional ideas on how to retain the cowl hing pin?
 
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I don?t see an example of ?doing it per plans?, which uses a hinge eyelet (well on the RV-7 plans anyway).

I have also seen metal 2d sculptures (like an art deco eagle heads for example) holding the pins in place.

I am sure you have thought of this but one advantage of the external retainer over a flush retainer is that you can install a quick and dirty retainer and get you plane in the air sooner. Then work on your master piece when your plane is flying. Good luck and have fun
 
I bought the hinge pins with the stainless "hinge loop" already welded on the ends....coudl have done something prettier, but Hugh is right - it got me in the air quicker!
 
Did my -8 from the inside of the cabin with a guild and it works very well, no exterior pins.
 
Hey Frank,

Show us a pic if you've got one. Many ways to do this, just curious
how yours turned out.

Did you get the paint job finished yet?
 
Using .125 aluminum stock cut to shape, beveled the edges on my 12" bench sander, thwacked the retainer with a rubber mallet bending the tip to conform to the curve, polished with rouge using a pad mounted on the drill press, then had a local engraver do the etching. The retainer is secured to the existing cowl hinge halfs with #6 screws and nutplates. I recently did the same thing with the -8 project but haven't yet decided how I want em engraved yet.

ao8ak2.jpg
 
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Here is....um....one way to do it. (I'm guessing this falls into the "ugly" category.) Oh, and it's not mine.


1001074cw0.jpg
 
The coolest hinge pin I ever saw

There is a Lanceair builders assist shop in Carlsbad CA that I visit whenever I am down there. I wish I had a picture of the way he did his hinge pins. I will try to explain. He took an allen end screw and centered drilled the end of the screw the same diameter of the hinge pin. Then silver solder the hinge pin to the end of the allen screw. He would offset the hinge in the cowl so the pin would enter below the split of the cowl. He would take a small block of aluminum and drill and tap it to fit the allen screw. He would grind the block to fit the lower forward of the cowl. He would flox the aluminum block to the forward cowl. With some glass work the head of the allen screw was countersunk and flush with the front of the cowl.
I tried to do a web search for a picture and found something simular. This is not necessary, you can do it yourself.

http://www.carbinge.com/Keepers.htm

Aaron
 
A great thread....keep the pix coming. Here's another very elegant solution. You can click on the photo for an enlargement and better definition.

 
No picture for a reason

Mine is the Sam James cowl; I don't know how this would work for the standard cowl.

I insert the pin from the aft end, going forward. The aft end of the pin is bent in an L shape for about an inch.

The pin is pushed beyond the flange that supports the MilSpec quarter turn fasteners and it hides behind the cowl. Of course, you have to have the quarter turn fasteners loose on the sides to do this.

When it's time to pull the pins, I use a special tool made by a friend of mine which is a handle from a hardware store bolt's shank and a loop made from safety wire. The tool must, thus, be carried in the plane for obvious reasons. You have to snag the L with the loop and pull.

In mine, the quarter turn fastener provides a stop to keep the pin from migrating behind the flange.

As you can tell from this description, there is simply nothing showing.
 
Another method

Here is my favorite way to do it. This depicts installing the hinge pin from the aft end forward. It is installed through a hole in the NACA duct, slides through a short length of plastic tube (epoxied to the inside of the skin), then through a small hole in the firewall, and finally into the hinge pieces in the cowling. The aft end of the hinge is bent 90? and is secured in the middle of a pop-rivet that was epoxied into the NACA duct, as well.
Advantages: Clean installation, no possible way the hinge can back out into the prop, no tools required to get the pin out, no extra parts to lose in the field.
Disadvantages: Can scratch the paint if you're not careful, have to plan ahead and cut your NACA duct hole in line with the cowl hinge.
Sorry for the quality of image - I don't have a closeup and I just zoomed in on a larger picture to try and show what I'm talking about.

CanopyHingePin.JPG
 
Imatation is Flattery

Rick,

Your cover is BEAUTIFUL!! That is a must have. Please consider my attempt to imitate it flattery. :)

Deal Fair
Rv-4
George West, TX
 
Hidden Hinge Pins

I stole this hinge pin idea from Danny King. Long hinge pins are inserted through the landing gear boxes and F-802 as shown above. They continue through the baggage compartment, firewall and into the hinges that attach the top and bottom cowl halves.

I used 1/8" rigid brass tubing held in place with JB Weld as a channel to guide the hinge pins through the gear boxes and F-802. A 12" drill bit was used to drill through the three bulkheads and keep the hole in line.

After 1175 hours of flight it still looks and works great!. Operationally, I have decided that the brass guide tubes are not really needed and the JB weld holding the guide tubes in place has long ago failed. I also now use a little model airplane collar with an allen set screw to keep them from creeping back into the cockpit. The best method for inserting them is to pass them through a paper towel sprayed with some sort of lubricant (LPS) as they are inserted. Of course I have trimmed the the pin to a reasonable length in the cockpit since this picture was taken.

cowlpin.jpg

Cowl_Stripes.jpg
 
cowl hing pins

Mine are installed and removed from inside the cabin. No external pin.

I used a short piece of 3/16" stainless brake line. Flared the end inside the cabin to make it easier to install the pin. This is held in place with an adel clamp on the vertical stringer inside the cabin.

A hole is drilled in the firewall that aligns the brake line and pin with the hinge. A little epoxy on the outside of the firewall to hold it in place.

The pin slides easily into place.....

Keith
N355RV
RV9A

90 hours.......:cool:
 
Concern: inserting from inside Firewall

I considered this but did not want to provide a path for flames no matter how slim the clearance.
 
I considered this but did not want to provide a path for flames no matter how slim the clearance.

Being in the heating business, and dealing with "flames" for a good part of the year; I don't believe I'd worry about a 3/16" stainless steel sleeve, that much. If the flames are that bad to penetrate, I think there are much worse problems.

However, a dab or of something (firewall seal, pro-seal)could always be placed on the end of the pin, where it makes contact to the sleeve (dried first), to seal any gap.

L.Adamson
 
I considered this but did not want to provide a path for flames no matter how slim the clearance.
My concern isn't so much about flame since the hole would be small, I'm more concern about the hole as a source CO into the cabin. Same thing with external solution into the NACA fresh air vent. A rubber plug on the pin may address that concern however.
 
My Socata has composite cowls very similar to Van's design, but they use machine screws to retain the bottom cowl and Cam-locks on the top. Looks great ... lasts a long time. Top cowl can be removed and replaced by one person in a couple of minutes. I will try and submit a picture later. Has anyone tried this type of setup?
 
Whats under the pin end cover plates?

I like the idea of the cover plate were the horizontal hinge pin comes out the front of the cowling and will be doing the same. What I have not seen and I don't know is how the end of the pin was bent. Was it bent at a 90 angle or a 180 degree loop? Was it left sticking out slightly so the cover plate pushed it in? Was the gap in the cowling large enough to reach in to grab the pin with a tool? Was the pin taken clear to the firewall to provide an aft stop? How well does it work?

Thanks
 
Hole in FW - follow up

Those who say the flame risk is not a big deal may be right. I'm no expert so I don't know. However, it is inconsistent with all the concern(s) I've seen on this forum for sealing the firewall where control cables and electric wires go through. And thanks for the CO warning - I had not thought of that. However, I suspect the risk of that is greater from my heater vent, closed or open.
 
Maybe Keith can comment: If you install your pins from inside the cabin, it is definitely a two person job whereas from the front of the cowl, one can accomplish it alone. True?
Ben Cunningham
RV7 last 2%
 
two man job

i dont know about the 7 but on my 4 i can get them in all by myshelf

bob burns
RV-4 N82RB
 
I like the idea of the cover plate were the horizontal hinge pin comes out the front of the cowling and will be doing the same. What I have not seen and I don't know is how the end of the pin was bent. Was it bent at a 90 angle or a 180 degree loop? Was it left sticking out slightly so the cover plate pushed it in?

Paint02.jpg

I bent the pin 90 degrees and drilled a hole in the clip to hold the pin in place.
 
How to secure top cowl hinge pins?

My top cowling hinge pin opening where it meets the top fuselage is looking a little ratty after 650 hours.
Plus the worn-in pins seems to slide around now.
Seems I've seen someone do a metal plate that fills in the void and locks the pins inplace. The plate is secured with one or two screws ????
Can anybody give me ideas on how to do this or point me to websites, etc.
so I can see some ideas? How do most other builders handle this, without switching to screws/nutplates or Skybolt fasteners!
Thanks in advance!
 
Sorry I don't have any pictures. But on my six, I had a approx. 1" by 2" square openning in the cowling where the pins met. A plate fit over the opening. At the forward edge of the plate there were two holes for screws and the cowling had plate nuts to accept the screws. The plate had a spacer and a short piece of angle riveted length wise to the bottom of the plate. The spacer dropped the angle just far enough to allow it to fit under
the fuse skin where it meets the cowling. The plate overlaps the fuse and
the cowling on all side. The angle prevents the pins from working out. To install, just slide the rear of the plate so that the riveted angle slides under
the skin, the plate is on the top of the skin pinning the plate after its screwed on. The pins cannot go any further than the angle. Hope
this isn't to confusing. I'm using the same setup on my 8A.
 
Thanks

Thanks guys.
Tom, I think I can picture it....I'm drawing sketches to help.
But that is the idea I'm after.......
I picture is worth 1000 words.

William,
I'm looking for the TOP cowl to fuselage area.......
I've thought about the front cover idea, but the edge of the cowl area makes it a little different situation.
Thanks for taking the time post the pictures and links.
 
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