Hinge cowl mounting

[Skint]

I followed along Vans hinge cowl fastening deal and have attached the upper hinge. Lots of people are now telling me that's a bad way to go and I would be better of to remove the hinge and attach an aluminum strip that can take camlocs.( Should have moved to the airport sooner!)

Comments, please and what thickness of aluminum should that new strip be?

[flyboy1963]

I've only owned my RV-9a for about 25 hours. IN that time, I've had my cowl off 25 times. the hinges drive me nuts.
IF you have a brand-new engine, don't like to tinker, and like the clean look, then the hinges are ok, with the caution about some cracking at the ends of the fibreglas etc.
If you MUSt look under the hood before each flight, or want to add a CHT, and then clean the lugs, and then time the mags, and then check the carb, and then add pre-heat pads etc. etc........then I think the camlocs will be more your thing....IMHO.

[Greg Arehart]

Skint,

I put camloks on the firewall portion of my upper cowl only. Everything else is the standard hinge fasteners. But, I have also seen a lot of RVs with all hinges. Either way works well, and the hinge fasteners do loosen up (i.e., become easier to pull and install) with time. I know I was dubious at first because the hinges were quite stiff, but now with 100 hours and multiple hundred cowl on/off sessions, the hinges are easy to work. That said, I do like the camloks on the upper cowl. If you go the camlok route (Skybolt or similar), you will want to use Al strips that are about 040 or 050 thick. O32 is a bit flimsy and 063 is pretty stiff. If you use the floating camlok systems, then you will need about an inch of strip in front of the firewall/top or side skin joint. Err on the side of too much rather than too little, as you can always trim stuff down after the cowl is mated to the strip. I used about 3.4 inch spacing between the camloks and if I had it to do over, I would add one or two camloks to decrease that spacing to around 3 inches, even though the instructions indicate that a 3.5-inch spacing is adequate.

cheers,
greg

[rvbuilder2002]

Originally Posted by flyboy1963

I've only owned my RV-9a for about 25 hours. IN that time, I've had my cowl off 25 times. the hinges drive me nuts.
IF you have a brand-new engine, don't like to tinker, and like the clean look, then the hinges are ok, with the caution about some cracking at the ends of the fibreglas etc.
If you MUSt look under the hood before each flight, or want to add a CHT, and then clean the lugs, and then time the mags, and then check the carb, and then add pre-heat pads etc. etc........then I think the camlocs will be more your thing....IMHO.

The difficulty in removing a cowl that has all hinges is effected by many factors. The initial installation, how many hours (break-in time) on the airplane , etc.

I strongly believe that if anyone with camlocks on an RV-6/7/9 top cowl wishes to have a top cowl removal race against me with my RV-6A, that I would easily win. I can do it in under 60 seconds if I needed too. Reinstalling it can be done in only a slightly longer time (maybe 1 1/2 minutes).

[John Clark]

Originally Posted by rvbuilder2002

The difficulty in removing a cowl that has all hinges is effected by many factors. The initial installation, how many hours (break-in time) on the airplane , etc.

I strongly believe that if anyone with camlocks on an RV-6/7/9 top cowl wishes to have a top cowl removal race against me with my RV-6A, that I would easily win. I can do it in under 60 seconds if I needed too. Reinstalling it can be done in only a slightly longer time (maybe 1 1/2 minutes).

I agree. I can get the cowl off my '8 in seconds. The trick is proper installation of the hinges and some fine tuning. Attention to the pins and a little lubrication helps too. At 300 hours no cracks or other issues.

John Clark
RV8 N18U "Sunshine"
KSBA

[Bob Axsom]

~550 hour of operation with the hinges used to mount the cowl. They work well and look outstanding. Continuous alignment along the interface and no exposed hardware - picture perfect and there is no way you can remove a series of camlocks as fast as I can pull the hinge pins. The bottom of the lower cowl is another matter. Structurally the design was inadequate for my RV-6A. The initial instalation with #3 rivets had the rivets working and poping heads early in the operational life of the airplane. I replaced them with #4 (1/8") rivets and they were better but they too started working the heads. I riveted 0.032 2024T3 aluminum plates from the fuselage (I think I had to put in spacers for proper alignment) that extended on the inside bottom of the lower cowl. I installed platenuts on the plates in alignment with the old rivet holes on the cowl and preped the cowl holes for #8 flathead screws and dimple washers. That fixed the the only problem I had with the cowl attachment design.

Bob Axsom

[L.Adamson]

I have all hinges except for the bottom also. They work slick, and look better!
After they've been installed a few times, and the plane flown, they are very easy to remove and replace.

Note: I did use an an offset hinge line for where the top & bottom cowls meet. There is lot's of info on this slight modification, which makes the top cowl removal easier. Perhaps it's standard now. I don't know.

L.Adamson -- RV6A (flying)

[rv9av8tr]

I've JUST finished installing the hinges on my -9A. They all go in snug, except the right side, mating top/bottom halves. The last 12" is REALLY tight.... looking forward to when they get "loose"!! I admit, I was skeptical, but I think it's a very clever and fast way.

[robertahegy]

I did the hinges and liked them very much. Proper installation is key, as previously stated. They will get easier as the engine heat tends to relaxed the cowl, making the fit better. and they look Great!!

Roberta