Best way to cut a hole in my airplane?

Grum.Man

Grum.Man

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Grum.Man
The bottom line is the ventilation in the Venture sucks to the point where it cannot be flown on hot days bellow 8,000 feet at least. It is down for it's condition inspection so I thought it would be a good time to address this. I ordered some side vents from Vans aircraft that are used for the rear seat passengers on the RV10. They are compact and small enough to fit easily on the side of the Venture. I plan to "glue" them on with proseal like many others have done to avoid having unsightly rivet heads. The question I have is what is the best way cut the hole in the side of the airplane without burning the paint? I have an oscillating tool that doesn't seem to build up much heat. A dremel tool I feel would burn it. I could use a hand saw but am afraid of jabbing the paint if it gets bound up. The other option is to use a hand nibbler to get close then lightly sand to the final dimensions.

Anyone have a better idea that is proven, not a guess?
 
I assume aluminum.
How big a hole?
How accurate does the hole need to be given that you are covering it up with a scoop?

Router with carbide bit
Rotozip with metal cutting bit
Hole saw (that would be my first choice)
Saber saw.
Fly cutters can be fun if you are willing to risk your fingers.
Nibbler works as well.

No guesses with any of these.
 
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Use a hole saw and some lubricant to keep the bit cool. It will give you the most concentric cutout, and shouldn't affect the paint more than a centimeter or so from the edge. It'd be covered by the flange for sure. One slip up with a Rotozip/Dremmel/Oscillating tool and you're fixing a bigger problem.
 
Hole will be rectangular in shape about 2" wide by 3" tall. It will not be covered up, the "scoop" sits flush with the side of the airplane until it is opened. And yes it is aluminum.
 
Grum.Man said:
Hole will be rectangular in shape about 2" wide by 3" tall. It will not be covered up, the "scoop" sits flush with the side of the airplane until it is opened. And yes it is aluminum.
Click to expand...

In that case, I'd probably use a Rotozip/Dremmel with a cut-off wheel like kyleb mentioned. Thin blade and shouldn't scar much of anything up, but it would be smart to put down some masking tape and cut through it. You can use snips, a file, or a hacksaw blade to finish out the corners of the cut if the cut-off wheel can't get to it. I'd stay away from any tool with an oscillating blade on thin aluminum.
 
The panel you're cutting probably isn't perfectly flat, right? Me? I'd use a die grinder or Dremel with a spiral cutter and would make a jig to guide it. The next option would be to drill the corners, connect the dots with a jigsaw, and finish with a file. With sharp tools there won't be any paint burning and proper masking will prevent any paint scratching.

My first choice would be to add adjustable inlet and outlet vents in the windows. Or add outlets like Soros vents aft on the bottom and then add adjustable inlets up front, probably in windows. If you want to allow air in you need to let air out. Round vents are way easier to cut. Electrician's hole saws for sheet metal are excellent for easily cutting precise holes. I'm talking about piloted annular cutters.

M2C1. Measure twice, cut once!
 
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Stewartb said:
The panel you're cutting probably isn't perfectly flat, right? Me? I'd use a die grinder or Dremel with a spiral cutter and would make a jig to guide it. The next option would be to drill the corners, connect the dots with a jigsaw, and finish with a file. With sharp tools there won't be any paint burning and proper masking will prevent any paint scratching.

My first choice would be to add adjustable inlet and outlet vents in the windows. Or add outlets like Soros vents aft on the bottom and then add adjustable inlets up front, probably in windows. If you want to allow air in you need to let air out.
Click to expand...

I will not be putting anything in the windows. For one, you cannot get canopies for the Venture anymore so if I screw up I'm in deep trouble. For two, there is no flat area to really put a vent. For three even if there were canopies, mine is a fully customized fiber glassed slider that took 700 hours to construct. Long story short, touching the canopy is out of the question.

The area I am putting the vent is relatively flat. I am liking the dremel with spiral idea.
 
Step drill to radius the corners, then dremel or nibbler for the straight bits. Be careful, aluminum tears easy.
 
Layout dimensions directly on the panel, drill holes in each corner with a #10 split point HSS bit. Make sure the holes fall just inside of the final dimensions. Layout lines between the holes, on center, such that the lines fall just inside the final dimensions. Use a die grinder with a cutoff wheel to cut along the inner lines to the corner holes. Use hand-nibbler to shape to final dimensions (pneumatic is too aggressive for this step). You may need a small deburring wheel on your die grinder or dremel if you're having trouble getting perfect edges with the nibbler. Take your time and go slow. Also, You may have to refresh the layout lines once or twice. Stop and do it before they disappear completely.

Make sure you radius the corners, sharp corners will develop stress cracks. Deburr all new egdes.

This is how I do it to install leading edge landing lights on wings. Works great.
 
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