[RVG8tor]

I am about to drill my horizontal hinge line in my cowl fitting process, which has gone surprisingly well not near the frustration I felt with the canopy skirt. I guess experience with the materials makes a difference.

At any rate the plans call for you to butt the horizontal hinge on top of the lower cowl vertical hinge. There is a gap in above the horizontal hinge before you get to the end of the upper cowl firewall hinge. It is about 3 rivets if you look at the hole pattern on the firewall.

The plans do not call for anything to go here and this seems like a place one might want the seam gap covered. My thought is to rivet a small tab onto the firewall flange that would cover this seam (no fastener thru cowl to this tab. I can also make it have a flange that I can use to anchor the hinge pins for the lower cowl vertical hinges. From what I see so far there is nothing in the plans to anchor these pins, perhaps because if the work loose they can't go very far.

So what if anything have you guys seen in this area. Essentially this is the space along the firewall from the top of the cowl horizontal seam and the start of the upper cowl firewall hinge. The only other area of the firewall with not hing is the bottom curves and these are very small runs.

Cheers, as always thanks.

 

[flyinga]

You are correct that there is nothing in this area. I did mine like the plans and have no issues with the "gap" below the upper verticle hinges. The horizintal hinge pins will hold the lower verticle hinge pins in. I had to make a small "bracket" to capture the upper hinge pins.

 

[RVG8tor]

Upper firewall hinges

You are correct that there is nothing in this area. I did mine like the plans and have no issues with the "gap" below the upper verticle hinges. The horizintal hinge pins will hold the lower verticle hinge pins in. I had to make a small "bracket" to capture the upper hinge pins.

Jim,

Thanks I had not though to that. I am am working on the upper hinges that go across the top of the firewall. Is there a need to secure them in any way. I plan a loop that lets me have a good hand hold on the end of the pin, my thought is the loop can be such that the two can be safety wired to each other, there could be some movement between them but not much. Or the loops could be fashioned to interlock to each other.

I am not even sure any of this is required but I could not find any information with the search function or in the plans.

I have nice fitting pins now. I am using full .120 sized pin but I tapered about 8" that goes into the curve down to .090, this I hope will eliminate upper cowl pucker! I can now get the pins in without much trouble.

Thanks

 

[flyinga]

I like your loop idea. I have 90 degree bends in mine and riveted a small angle to the firewall. I put notches in the angle to capture the pins.

Your idea of tapering the .120 pins is good too. I used the recommended .090 pin and do get a little bulge in flight; looks good on the ground and since I am the only one that can see it in flight I'll live with it.

 

[RVG8tor]

Taper works nice

Yesterday I made the taper in the hinges and fit them and it works great. The pin was a tough to bend the loops in but all worked.

I chucked the pin in my Ryobi angle drill and used a clamp to keep it running. I supported the opposite end of the pin by pushing it through a cardboard box. Then first with the Dremel with a rotary burr to get a good shape going, then with a belt sander to smooth it out and ended with several grits of cloth tape.

The loops intersect with a place to safety wire but I honestly don't think it is required. I have done my fitting with the full size stock pins and a lot of in and out, and they were tough to install. The tapered pins go in much easier. My taper runs from .090 at the end then tapers up to the full size of the pin over 8 inches.

The taper jig!

 

[gasman]

I wish you success with those full size hinge pins. There will be over double the install drag with the other half in place, and you won't be able to push from the end of the pin to start the install.

 

[RVG8tor]

Actually no

I wish you success with those full size hinge pins. There will be over double the install drag with the other half in place, and you won't be able to push from the end of the pin to start the install.

I have installed the top cowl twice already and the pins go in easier with the two halves of the hinge. Without the other hinge half the pin has nothing to guide it between eyes, with the hinge together there is only a tiny gap between eye seams. If the pin hangs up a little rotation here and there and it slides right through.

Cheers

 

[Frank Smidler]

No retainer on top hinge pins needed

Jim,

I am am working on the upper hinges that go across the top of the firewall. Is there a need to secure them in any way. I plan a loop that lets me have a good hand hold on the end of the pin, my thought is the loop can be such that the two can be safety wired to each other, there could be some movement between them but not much. Or the loops could be fashioned to interlock to each other.

Thanks

I wondered the same thing. I ended up just putting 4" bends on the ends of the pins for the hinges across the top of the cowl with nothing retaining them. In 360 hours they have never moved and can be removed and installed easily. I believe that the ends being lower than the handles results in gravity keeping them in place and not backing out.

This is not true with the bottom hinges. Originally I did not retain these pins and had to check them before every flight as they would back out an inch or so after a couple of hours. I have since made retainers for the handles out of safety wire. I wrapped emergency tape around the engine mount tube nearest the handle, made a small loop in the middle of a short length of safety wire, twisted it for an inch or so, and them twisted the free ends around the tube. This flexes easily up to engage the end of the hinge pin handle.

 

[RVG8tor]

Which bottom hinge

I wondered the same thing. I ended up just putting 4" bends on the ends of the pins for the hinges across the top of the cowl with nothing retaining them. In 360 hours they have never moved and can be removed and installed easily. I believe that the ends being lower than the handles results in gravity keeping them in place and not backing out.

This is not true with the bottom hinges. Originally I did not retain these pins and had to check them before every flight as they would back out an inch or so after a couple of hours. I have since made retainers for the handles out of safety wire. I wrapped emergency tape around the engine mount tube nearest the handle, made a small loop in the middle of a short length of safety wire, twisted it for an inch or so, and them twisted the free ends around the tube. This flexes easily up to engage the end of the hinge pin handle.

Frank,

When you say the bottom hinges, are you talking about the two small sections of hinge between the exhaust or the vertical section of hinge on the lower cowl?

In looking at things installed now I don't think I will need to secure the vertical hinge in the bottom cowl (sides of firewall), this pin bumps the upper cowl horizontal hinge enough to keep it in place.

I plan Camloc fasteners where the short bottom hinges go since I read this is a place many get a broken hinge.

Thanks

 

[Frank Smidler]

Frank,

When you say the bottom hinges, are you talking about the two small sections of hinge between the exhaust or the vertical section of hinge on the lower cowl?

In looking at things installed now I don't think I will need to secure the vertical hinge in the bottom cowl (sides of firewall), this pin bumps the upper cowl horizontal hinge enough to keep it in place.

I plan Camloc fasteners where the short bottom hinges go since I read this is a place many get a broken hinge.

Thanks

When I spoke of the bottom hinge I did indeed mean the bottom horizontal hinges. They are longer on the RV-6 than on your RV-8. My solution is a moot point if you will be using Camloc, a good option. The lower cowl vertical pins did not need any type of retention. I used a straight 3" handle on them and they never have moved. I was concerned they would move against the motor mount and rub but so far they have not.