Which hinges on cowl: where and why?

[AFulmer]

It has been several years since I inventoried my finish kit so I have kind of lost track of which hinge goes where and why.

If I understand DWG#45 for RV7 cowl there are two types of hinges material specified and 2 types of hinge pins:
The side hinges that connect the top and bottom halves are AN257-P3. These get a .090 stainless pin.
Top, bottom, and sides of cowl use ?1/8? piano hinge? (which is different from AN257-P3), and get a 1/8? SS pin EXCEPT the top hinges that get a .090 SS pin.

Why not use the same 1/8? piano hinge on the cowl sides? (It looks so much more substantial.) Not as much load I guess?

I had to order the AN257-P3 since I had ?cannibalized? some of it (for something) and I ordered some P3 and P4 (1/8? wider, same pin dia.) figuring I would make the two side hinges using half P3 and half P4 and set the bottom half up enough so the ?loops? would not show at the parting line between the cowl halves. Other than being a little anal about it, does anyone see any problems with this idea?

Other than the increased cost would it be any better to use the extruded hinge material?

Thanks,

Allen Fulmer
N808AF reserved
RV7 fitting cowl

 

[rocketbob]

Other than the increased cost would it be any better to use the extruded hinge material?

On my -6 I've had a few broken hinge eyes towards the front. I put extruded hinges on my Rocket, and camlocks on the cowl. I strongly recommend against hinges on the top cowling. As the hinges wear from vibration the pin becomes much harder to insert. On mine in fact is an absolute pain to put the top hinge pin in.

 

[uk_figs]

use extruded on lower cowl

I would definitely use the extruded hinge on the lower cowl bottom as the standard hinge has a tendency to break due to the vibration. There are some threads on that issue in the forums including some mods to improve the situation.
Like a number of people I had to replace mine after only 20 hours.

 

[dav1111]

Cowl Hinge Pins

I love my side hinge pins. However a would never again put hinge pins on the bottom firewall attachment. Cam Locks are the only way to go. I like the look of the hinge pins across the top of the firewall but have gone with camlocks for better efficiency.

 

[lostpilot28]

Somehow, when I got my kit it had the smaller hinges, not the 1/8" that "normally" come in the kit. I didn't know any better at the time, and I installed the smaller hinges everywhere. I checked with Van's after I found out what I did and they said no problem, they'll just be a little harder to get the pins in and out of.

This probably doesn't help you, but I wanted to share anyway.

 

[Snowflake]

If I were doing it from the beginning, I would use hinge pins to join the top and bottom, and to join the vertical seams of the lower cowl to the firewall. For the seams along the top and bottom of the cowl, i'd use camlocks.

The hinges along the top of my cowl are getting rough with age, and it's a pain to get them to mesh properly when removing/installing the cowl. The lower hinges on the bottom cowl started shedding eyelets this year, and instead of replacing with a hinge that would fail again, I replaced the inboard 6" worth with a plate mounted to the firewall so I could put screws through the cowl into platenuts instead. Maybe this winter i'll replace the whole hinge along the bottom with a proper set of camlocks.

But in general, hinges on the straight seams, screws/camlocks on the curved seams, except for the lower seam where it should have camlocks too.

Oh, and for the top/bottom seam, i'd make the hinge pin come out through the air vent in the side of the fuselage, not out through the front of the cowl.

 

[apkp777]

I started with hinges. I didn't love them at all. Decided to go with Skybolts until I saw the price. Ended up removed the firewall hinges all the way around, installing the splice straps and used floating nutplates with stainless hardware. PERFECT!