Cowl hinge question

bifft · #1 09-06-2016, 10:23 PM

Finishing up my 8A. Spent about 30 minutes trying to get the top cowl on yesterday. If the rear hinge was lined up, the side hinges were out of alignment and vice versa. I know I've had it on before, but it has always been difficult. So, I was thinking last night, if I cut away the fiberglass on the bottom to the depth of the "teeth", I can get the rear hinge lined up, and then push the the sides in from the outside (where they almost always end up).

Will mean some more leakage through the sides. Anyone think this would actually be a problem? The other option I thought of is to go with screws or something, lots more extra work, would add some weight.

RV Jerry · #2 09-07-2016, 09:40 AM

Quite often after flying a few hours things will settle in . In the mean time a .078 pin will some times fit ,I have used the Bowden inner cable available from ACS. I wouldn't cut the fiberglass

rvbuilder2002 · #3 09-07-2016, 10:07 AM

Quote:

Originally Posted by bifft

Finishing up my 8A. Spent about 30 minutes trying to get the top cowl on yesterday. If the rear hinge was lined up, the side hinges were out of alignment and vice versa. I know I've had it on before, but it has always been difficult. So, I was thinking last night, if I cut away the fiberglass on the bottom to the depth of the "teeth", I can get the rear hinge lined up, and then push the the sides in from the outside (where they almost always end up).

Will mean some more leakage through the sides. Anyone think this would actually be a problem? The other option I thought of is to go with screws or something, lots more extra work, would add some weight.

Section View P-P on DWG 48 shows that the hinge pin center should drift above the split line as it moves aft. This resolves the issue of the hinge loops being caught behind the cowl (On the later RV models the plans just specific doing this along the entire length of the hinge.... makes cowl installation and removal much easier).
If this was not done it would still be pretty easy to fix as long as the cowl isn't painted.

RV Jerry · #4 09-07-2016, 01:07 PM

I didn't read the post carefully, what Scott says is the best

bifft · #5 09-07-2016, 09:42 PM

Quote:

Originally Posted by rvbuilder2002

Section View P-P on DWG 48 shows that the hinge pin center should drift above the split line as it moves aft. This resolves the issue of the hinge loops being caught behind the cowl (On the later RV models the plans just specific doing this along the entire length of the hinge.... makes cowl installation and removal much easier).
If this was not done it would still be pretty easy to fix as long as the cowl isn't painted.

Thanks, I must have missed that when riveting it. Sadly cowl is already painted, so won't be all that easy. I may just leave a gap in the glass. Did bring it home from the airport so will be easier to work on.

sglynn · #6 11-20-2016, 07:36 PM

Please how easy is it to install top cowl pins on 7A made per plans with hinges? I just installed hinges on firewall and getting ready to cut cowl to length. But putting the hinge pins in the top hinge is really difficult. Yes I'm using the 0.09 pin in the 1/8 hinge but still I have to push on each tooth going around the curve to get the pin in. Doesn't seem like I'd ever get the pins in when finished and the only room there is is reaching thru the oil door hole. Also seems like I will want to remove the cowl often for inspection and maintenance and if it is a total pain to put the pins in then that will be bad.

How about some testimonies on installing the hinge pins? It is not too late for me to learn how to do camlocs.

flyboy1963 · #7 11-20-2016, 07:53 PM

Steve, I am not a big fan of the hinge cowl closure, and agree the rear one is a pain.
here's some coping ideas, other than large doses of sedative and/or Red Bull.

- pre-bend the .09" wire to the shape of the curve....even overbend the tip so it's catching the next hole.
- use LOTS of lube until vibration and the 327 cowl removals in the first year break things in a bit.
- stand on a little step. really. changes how far you can stick your right arm in, and use your thumb to push the wire into alignment with the first hinge hole....then you can feed aggressively with the left. ( or is it your teeth? I forget!)
- maybe you wanna lose the first hinge holey thing, or REALLY open it up like a funnel. I have about a 4" gap, and yes it bulges up a tiny bit in flight, but hey, it's gotta be functional first.
- get a helper for the first while. with someone to lift up on the cowl, and you with your arm inside the oil door, you can probably avoid catching the loops all the time.
- Put in another door on the other side. Hundreds of uses...like actual preflights, battery charging, heat expulsion on the ramp, lining up the dang cowling, etc etc.

YellowJacket RV9 · #8 11-20-2016, 08:02 PM

I cursed at the top cowl pins all through building my cowl. Within 10 flight hours though, things had loosened up enough that it is a non-issue.

Chris

DrillBit · #9 11-20-2016, 11:23 PM

Quote:

Originally Posted by flyboy1963

- Put in another door on the other side. Hundreds of uses...like actual preflights, battery charging, heat expulsion on the ramp, lining up the dang cowling, etc etc.

I like the hardware-free look of hinges all around. But I sure didn't like the thought of putting in the upper aft pins through the oil door for the rest of my life with the plane....

I cut out narrow strips from the upper cowl, from the split line to the height of the half hinge attached to the firewall. The pins go in "from the bottom" from each side. The strip was wide enough to glass in a lip to attach laid-up-in-place-glass-cover with screws. Much like the covers some make to secure the pins that hold the upper and lower cowl together at the front. Had I thought about it at the time, I wouldn't have left the gap where the pins are supposed to go in through the oil door. Maybe an "after flying" addition...or live with an in flight passive "cowl flap."