L

lr172

Well Known Member
Mid-stream in fitting the cowl for my 6A. Using hinges for the lower vertical and upper/lower joint. My plans show the larger 1/8" hinge for all areas except the upper/lower joint. Here they specify the smaller 257-p3 hinge. This seems a bit lightweight for the job and I have seen a post or two where the 1/8" hinge is used in this area. I have enough 1/8" hinge for this joint. Is that recommended?

Thanks for your guidance and insight.

Larry
 
Be kinda stiff. The 257 works fine. I like to mount that hinge as high as rivetly possible. That way it hides the loops and you don't have jack 'o' lantern sides.
 
aerhed said:
Be kinda stiff. The 257 works fine. I like to mount that hinge as high as rivetly possible. That way it hides the loops and you don't have jack 'o' lantern sides.
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I'm coming to this part soon, and don't quite understand your "mount that hinge as high as rivetly possible" comment.

Could you elaborate please?
 
Hi Gil!!

finally a question that I can answer for you!

You can offset the hinge higher (or lower) on the split between the cowling upper and lower. Making the 'view' between the two smooth aluminum instead of the loops that you put the rod through. Much better look! You can also order hinge with one 'leg' of the hinge taller than the other to facilitate the offset....

Best wishes!! Greg
 
I had some NOS extruded hinge with 1" flange in my stores (MS20001P-6) so I used it for the lower half of the cowl split line. The pin geometry is the same as the rolled hinge supplied by Vans so the rolled hinge went on the top cowl.

The long flange allowed me to extend the lower hinge up to do two jobs. First, it makes the top cowl really easy to allign on installation and second there is no sawtooth (of the hinge loops) visible at the split line.

Pictures here
 
Extruded at bottom

Assuming the 6 is somewhat like the 7 I would recommend using the extruded 1/8 at the bottom of the cowl, there are some threads here but basically the vibration from the exhaust system causes the rolled eylets to crack off over time. I lost a few and then replaced the strip with the extruded version and 200 hrs later have no problems so far.
 
uk_figs said:
Assuming the 6 is somewhat like the 7 I would recommend using the extruded 1/8 at the bottom of the cowl, there are some threads here but basically the vibration from the exhaust system causes the rolled eylets to crack off over time. I lost a few and then replaced the strip with the extruded version and 200 hrs later have no problems so far.
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I have read quite a few posts on this subject and decided to use screws on upper and lower connection points, as well as the small attach point in the nostirls. It would seem that these three locations take the brunt of load in holding the cowl in place. The others seem to just hold it together.

I had a follow up question. My hinges all have alum. rods in them, but my kit had steel rods as well. Should I use the steel rods in the the hinges, like my flaps?

Larry
 
lr172 said:
I have read quite a few posts on this subject and decided to use screws on upper and lower connection points, as well as the small attach point in the nostirls. It would seem that these three locations take the brunt of load in holding the cowl in place. The others seem to just hold it together.

I had a follow up question. My hinges all have alum. rods in them, but my kit had steel rods as well. Should I use the steel rods in the the hinges, like my flaps?

Larry
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That is going to be my screws + hinge strategy too.

Hinge pins - I don't think any are aluminum, the choices are stainless and corrosion resistant steel.

UPDATE -

From the Mil-Spec -

HINGE PINS SHALL BE IN ACCORDANCE WITH MS20253, USE CADMIUM PLATED CORROSION RESISTANT STEEL PIN WITH
ALUMINUM ALLOY HINGE. USE PASSIVATED CORROSION RESISTANT STEEL PIN WITH CORROSION RESISTANT STEEL HINGE.

Stainless may be an upgrade if you are subject to more corrosion -

http://www.aircraftspruce.com/catalog/mepages/hingepin-ss.php

Also from Vans

https://www.vansaircraft.com/cgi-bi...8988192-304-555&browse=hardware&product=hinge
 
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az_gila said:
Hinge pins - I don't think any are aluminum, the choices are stainless and corrosion resistant steel.
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Gil,
I thought it was odd, but my 1/8" hinge came with aluminum pin from Vans. They did supply steel (or CRS) pins to replace the aluminum.

My assumption was that the 1/8" hinge material supplied was not from an aviation source and the naming convention on your Vans link above kind of corroborates that.
 
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Taper some 1/8th pin

For the top hinge pins, I wanted the benefit of tight pin for the majority of the hinge and flexible end for going around the curve. So i used a 1/8th pin and I tapered the last 10 inches of the end of the pin easily by spinning the still straight pin in a battery drill while holding on a belt sander with a block of wood. 5 minutes work. Then sand a round end on the tapered end so it does not catch on the hing loops. Works great and hinges have no movement at all.
Morris.
 
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