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Apr 28, 2016, 09:15 AM
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Build Log

Epee


I am going to try and document the design and build process of my new plane the EPEE. If you speak French you know what that means. I don't but I do a lot of crossword puzzles.

This will start out pretty old school and hopefully move into the 21st century pretty quickly. I have bagged a rough draft of the wing and once I have proof of concept I will switch to molds.

The fuse is a 1pc design and it is a combination of old and new. The method is old school and the materials are new. I will be using a plug and parting tray to fabricate a mold. However the plug is Corian and Stainless Steel. When it comes to smaller parts this seems like a nice way to go, and I had no choice.

With smaller parts I pictured it being more difficult to get a mold all polished up than it would be to polish the plug. I have sausage hands and getting down into the nose or the boom section to sand and polish a mold did not appeal to me.

My ultimate goal is a nice flying 1M that flies well, is durable and above all brings new people out to fly with us.

Here are some pics of how my progress and notes on the construction.

The wing is a 40psi foam with a skin of 1.6 glass and doublers. Some of the doublers are probably overkill. The wing weighs 66 grams

The fuse plug is designed to hold 3 nano servos such as D47's or similar along with a small lipo and micro rx. I started by drawing the profile including the wing area. I then cut two pieces of Corian based on that pattern. I epoxied them together and then sanded clean. Once that was done I cut a notch in the back to receive the boom mandrel. I epoxied that with a mix of fumed silica and epoxy. From there is was all sanding and shaping.

For the wing saddle I used a digital meter to level the boom and then potted the wing so the angles would be right. This gave me a pefect wing saddle.

The tails are 40spi foam with 1.1oz skins and 1.6oz leading edges. The vertical has a glass wrap all the way around to add strength. They are 6.5 grams

Enjoy and comment if you have ideas.
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Apr 28, 2016, 10:06 AM
Registered User
Nice work Paul really like the longer nose on the fuse look forward to seeing the end results
Apr 28, 2016, 11:46 AM
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Thanks Don, I went with the longer nose in the hopes it will help with balance and end up helping the launch.

I am very excited about this project !! I am just crazy enough to fly them in events. I may have to bring one of my kids to watch it for me if I get too high though...
Apr 28, 2016, 01:52 PM
Registered User
Looks neat. Looking forward to pics and flight vids!

-Dave
Apr 28, 2016, 02:24 PM
Aurora Builder
Looks nice Paul. Good idea to go with the plug. I think if I make a new fuselage mold it would be done in similar fashion, using corian for a plug and building a composite + sand mold.
Apr 28, 2016, 02:38 PM
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Thanks Sam, Tom gave me some input and I am going to shorten the nose a bit. Since D47's are so thin I may move them to the wings and make the pod sized for a JR188 (or similar) a lipo and the rx.
Apr 28, 2016, 03:27 PM
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rdwoebke's Avatar
Is that corian pod for making a plug for a mold?

Ryan
Latest blog entry: Supergee wing mount pylons
Apr 28, 2016, 03:31 PM
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sporter's Avatar
It looks like the transition between the pod and boom is abrupt. Do you plan on smoothing that out? Most modern molded fuses are pretty clean from this perspective.

Sean
Apr 28, 2016, 03:49 PM
Aurora Builder
I suspect what Paul has now may be better aerodynamically (cleaner flow around the TE of the wing, more saddle-esque). Current 'modern' molded fuses have that a bit smoother for structural reasons and layup reasons, so keep those in mind...

I was going to suggest shortening the nose a wee bit, and possibly reducing boom diameter a tad. I still suggest a pod setup capable of 4 in the pod (2 x 188, 2 x D47's)..it will be tight but gives you some options on the wing. Also gives those who prefer flying with a rudder that option
Apr 28, 2016, 06:39 PM
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Quote:
Originally Posted by sporter
It looks like the transition between the pod and boom is abrupt. Do you plan on smoothing that out? Most modern molded fuses are pretty clean from this perspective.

Sean
Sean,

you are correct I left the transition below the wing quite sharp compared to some fuses. I did this so the trailing edge of the wing would be uncluttered. I am not sure why this would be correct in scientific terms but it looked right to me.

The back of the wing saddle is rounded like the back of a 911 and again I did this because it just made sense.
Apr 28, 2016, 06:45 PM
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Quote:
Originally Posted by rdwoebke
Is that corian pod for making a plug for a mold?

Ryan
Ryan,
that is a Corian and steel plug for making a fuse mold. Basically that is exactly what the shape of the fuse will be. But with a shorted nose......
This is how most guys made molds before CNC's were so obtainable. For something this small a plug to mold may be an easier way to go.

Sam,
I almost went with a smaller boom section but the larger OD will allow me to make it lighter and still be plenty stiff. It will also make construction much easier. It really isn't all that large when you hold it. Right under the saddle is .5" and it tapers to .375" and that will be the OD of the fuse.
Apr 28, 2016, 09:06 PM
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Ward Hagaman's Avatar
Nice! Paul did you make that mandrel, or do you have a source?

Ward
Apr 28, 2016, 09:15 PM
Aurora Builder
Neat Paul. If I were to make a fuse mold tomorrow, it would be with a CNC milled plug. The geometry doesn't lend itself well to going straight to a female tool. It can be done but to do it right I think it is much more time.
Apr 28, 2016, 09:26 PM
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woogie_man's Avatar
Really neat to see how these are made. You can really see the amount of dedication and thought that is needed.
Apr 28, 2016, 09:31 PM
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Quote:
Originally Posted by Ward Hagaman
Nice! Paul did you make that mandrel, or do you have a source?

Ward
Ward, I use stepless steel golf shafts. You can get different lengths and tip diameters depending on whether it is for an iron or a wood. My local GolfSmith store had some stepless putter shafts for under $6. Carbon shafts will work but I trust the release from the steel much more than from the carbon. Iron shaft tips are .375 and woods are .335.


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