Engineering advice

[fly_tornado]

I need some advice with this...

 

I am replacing the rolled hinges in my wings with extruded.

 

so after removing them from the plane I laid them out on some translucent plastic and drilled and clecoed them to the plastic. Then I finished marking the edges with permanent marker and drilled all the holes.

 

I aligned and glued the new hinges to the plastic using the permanent marker edges and marked the holes with permanent marker on the alloy. The plan is to now drill the holes through the marker with a guide.

 

Problem I have noticed is the rolled hinges where coming apart slightly which made them a bit oddly shaped

 

there are 7 photos from this one on

 

http://s880.photobucket.com/albums/ac7/flynow2010/mytornados/?action=view&current=P1110413.jpg

 

Any suggestions or ideas before I start drilling?

 

 

[pylon500]

OK, just looked at photo's.

 

You're on the right track, but the critical part in hinges is the hinge line, you need to know exactly where it is to get it right.

 

You need enough material to to create patterns of ALL the hinge pieces, not just one and reproduce it, (Titan may have done this with a jig, but you always get movement).

 

As for the rolled hinge being a bit open, before separating, lay the hinge on top of a vice with the roll in the gap, and gently close the hinge.

 

1.Number all your pieces, as you have done, then separate all the hinges.

 

2.Cut up your extruded stock into the sizes required and NUMBER.

 

3.Using some form of clamp (duckbill grips, G clamps, even a vice), clamp a piece of hinge (new or old) onto your template material, can be plastic but a bit of alloy sheet is probably better (and cheaper), this is the guide hinge.

 

4.Take an old hinge and using the pivot pin rod, mesh the old with the piece that is clamped and fit pin.

 

5.Drill the holes of the old hinge into the pattern material, try using a drill with a fairly flat point, or it will walk around in the hole.

 

6.NUMBER the new hinge and put aside.

 

7.Unclamp the guide hinge and move to a new area and re-clamp as per step 3.

 

8.Repeat steps 3 to 7, remembering to NUMBER all new pieces.

 

You will end up with a bit of pattern material that looks like swiss cheese, but each hinge piece will be a perfect copy of the original hinge.

 

As for assembly, a good trick would be to rivet every piece of hinge in it's respective place with ONE rivet in the middle, then fit the hinge pins.

 

Now hold the aileron up at 90°, and install the other rivets, this will keep the hinge line straight.

 

See how you go....

 

Arthur.

 

 

[Yenn]

If you are concerned about the drill bit wandering around there is a good trick to match drilling. Get a piece of short tube that fits the original holes neatly. Make it yourself if necessary. Put this in the hole and drill through the tube with a bit that is the same size a the tube interior. This locates the drill centrally and if necessary prevents the drill damaging the edge of the original hole.

 

 

[Thruster87]

You can use a AN bolt of the correct DIA, then drill it in a lathe to make a drill bush.Just did one to replace a DC4 bathtub fitting [outer wing attach point] Cheers

 

 

[fly_tornado]

Thanks for that. getting closer to working my problems out. I am going to have another go at marking the hinges on plastic with an aim to getting that centreline better defined.