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  #1  
Old 05-29-2012, 11:59 AM
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nukemmcssret nukemmcssret is offline
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Default rounding over a leading edge

rthis may sound like a silly question but how do you get an even roundnes on a leading edge like in the picture? Thanks Chief
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Old 05-29-2012, 12:09 PM
stefanj stefanj is offline
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First sand a 45 degree angle into the sides of the leading edge. Don't make a wedge; you're shooting for something like this:

_
/ \
| |

Lay out a sheet of sandpaper on a flat surface.

Hold the fin so it is lying almost flat against the paper, with your fingers under the trailing edge. Pull the fin toward you, with the line of the leading edge perpendicular to the direction of the motion. Lift the rear edge so that the leading edge "rolls" as slides along the paper; at the end of the draw the fin should be "standing up". Repeat this with the other side of the fin.

Do this, alternating sides, until your angled leading has a symmetrical curve.

Then wrap a small sheet of very fine sandpaper over the new leading edge and smooth out the curve.
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Old 05-29-2012, 12:37 PM
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I prefer short ogive curves to hemi. I fly transonic a lot.

I use the method stated without the last step of a small piece over the edge.

Jerry
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Old 05-29-2012, 02:11 PM
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Take your time and make the end look just right. The rest of the leading edge can be a little off and nobody will notice.
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Old 05-29-2012, 08:56 PM
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I just freehand it, but pre-bevelling does sound like a good idea.

BTW, what are you building chief. I can't quite tell from the page.
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Old 05-29-2012, 11:07 PM
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Quote:
Originally Posted by jeffyjeep
BTW, what are you building chief. I can't quite tell from the page.



That would be an Estes EPM-010. I have one in my queue right now.


Bill
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Old 05-30-2012, 10:06 AM
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Quote:
Originally Posted by Bill
That would be an Estes EPM-010. I have one in my queue right now.


Bill

Thank you Bill you are correct. THE Estes EPM-010. Jeff EPM sounded like something we know about so I bought it.
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Old 05-30-2012, 07:00 PM
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Quote:
Originally Posted by nukemmcssret
Thank you Bill you are correct. THE Estes EPM-010. Jeff EPM sounded like something we know about so I bought it.

LOL. 3 knots max speed for a Sturgeon Class boat on the EPM!
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Old 05-30-2012, 07:07 PM
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Chief, I've built only one EPM so far. The best advice I can give you is to PLEASE paint the little white nose cones and the rest of the rocket separately, and then glue the cones into the BT-5's. It will save a A LOT of extra masking (and naughty words.)

Hence:
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Old 06-01-2012, 09:34 AM
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Quote:
Originally Posted by jeffyjeep
Chief, I've built only one EPM so far. The best advice I can give you is to PLEASE paint the little white nose cones and the rest of the rocket separately, and then glue the cones into the BT-5's. It will save a A LOT of extra masking (and naughty words.)

Hence:


Ditto
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