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-   -   Amadeus (https://www.rcuniverse.com/forum/electric-pattern-aircraft-385/11618998-amadeus.html)

RodneyFord 06-28-2015 12:01 PM

Amadeus
 
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Time for a new F3a model. Electric this time. Working name is Amadeus. The fuselage will be molded and the wings balsa on foam. I will cover the molding process, which is something not seen here much.

RodneyFord 06-28-2015 12:42 PM

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Here are some dimensions.

RodneyFord 06-28-2015 02:07 PM

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I will go through the process I use to make a composite fuselage. I'm up to about 10 now, the last 2 were 40% IMAC so this one is relatively small:D.
I dimension the drawing at 100mm stations and transfer it to 6mm MDF. The off cut will be the splitter plate, more on that later.

ppljr 06-28-2015 02:33 PM

Nice. Be watching with interest.

RodneyFord 06-28-2015 02:37 PM

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From this point I will use different methods to build the fuselage shape. My first plan was to cut 100mm long cross sections derived from the Solidworks model. However I wasn't entirely happy with the shaping in solidworks so I am going to do the shaping free hand using profile gauges to get symmetry. I did use the CNC foam cutter to do the top view though.

http://www.rcuniverse.com/forum/atta...mentid=2106221http://www.rcuniverse.com/forum/atta...mentid=2106222

RodneyFord 06-28-2015 02:49 PM

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Vacuum bagged the other side on. Am using PU glue as it is fairly fast gap filling and works well in the vacuum bag. I have 2 vacuum pumps. This one is for white foam as is a diaphragm pump and is happy running at reduced pressure (5psi here) so it doesn't collapse the foam. The other pump is an oil filled vane pump for composites in molds and is best run at full vacuum or the oil drains out:(.

RodneyFord 06-28-2015 03:03 PM

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Trimmed of the outline with a hand held hot wire. Powersupply is a transformer on a light dimmer.
Started roughing out the shape with a bread knife.



http://www.rcuniverse.com/forum/atta...mentid=2106229

RodneyFord 06-28-2015 03:09 PM

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The canopy/hatch got cut out of the profile and foam glued to it.

http://www.rcuniverse.com/forum/atta...mentid=2106231

RodneyFord 06-28-2015 03:23 PM

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The fin is built up for accuracy. I use Profilli pro for my airfoil work. The airfoil is SD 8020 with the trailing edge thickened to a blunt 6mm and the root high point moved back to blend into the fuselage. The solidworks model helped to visualise the fit. Once the design was sorted out I printed out the ribs and used a glue stick to attach the printouts to the balsa. Lots of ribs for stiffness. Also made some leading edge templates for accuracy.

http://www.rcuniverse.com/forum/atta...mentid=2106238 http://www.rcuniverse.com/forum/atta...mentid=2106235 http://www.rcuniverse.com/forum/atta...mentid=2106237 http://www.rcuniverse.com/forum/atta...mentid=2106236

RodneyFord 06-28-2015 03:27 PM

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Did some rough sanding. 40 grit in one hand and vacuum cleaner in the other:D. Foam can get messy real fast:(.

RodneyFord 06-28-2015 03:32 PM

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Added the hatch base. This is the zero line to set everything from.

RodneyFord 06-28-2015 03:41 PM

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Used the canopy base to set the nose angle at 1/2 degree. There will be no right thrust as the model will have a contra drive or use throttle to rudder mixing if only one prop.

RodneyFord 06-28-2015 04:08 PM

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Glued on the nose ring. Triangulated it for squareness.

http://www.rcuniverse.com/forum/atta...mentid=2106247

RodneyFord 06-28-2015 04:59 PM

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Gluing the canopy base on.

ppljr 06-28-2015 05:45 PM

What was wrong with the shaping in Solidworks? I have had good success with Rhino 3d.

RodneyFord 06-28-2015 06:18 PM


Originally Posted by ppljr (Post 12062729)
What was wrong with the shaping in Solidworks? I have had good success with Rhino 3d.

Solidworks is great. Use it for the 3D printer. For this kind of flowing curve shaping I think Rhino might be better, you know pulling it around with handles. Especially the nose area which is going to be quite complex. I am pretty comfortable with eyeballing it freehand, I think I will get a better result.
Talking about the 3D printer, I will use it to make some parts. I am thinking of inserts to go into the mold for air exhausts. Spat and leg patterns. Am experimenting with nylon filament with a view to doing the 95mm spinner.

RodneyFord 06-28-2015 07:15 PM

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Did some rough shaping on the lower nose area. Actually nothing complex here, just want it fairly low drag and smooth here to get the air moving down the fuselage easily. Not worried about taking off too much foam as it is easy to build up later with bondo after it gets glassed. Much harder to take glass away and redo it.

http://www.rcuniverse.com/forum/atta...mentid=2106277 http://www.rcuniverse.com/forum/atta...mentid=2106278 http://www.rcuniverse.com/forum/atta...mentid=2106279

RodneyFord 06-28-2015 09:19 PM

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Double sided tape on some thin card to hold the canopy in place for shaping.

RodneyFord 06-29-2015 04:04 PM

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Got some section lines on so I could see the curves more easily and to check symmetry with the profile gauge. http://www.rcuniverse.com/forum/atta...mentid=2106419 http://www.rcuniverse.com/forum/atta...mentid=2106420 http://www.rcuniverse.com/forum/atta...mentid=2106421 http://www.rcuniverse.com/forum/atta...mentid=2106422

brustyrc 06-29-2015 10:17 PM

Very nice work as usual Rob, I'll follow this with interest, 'best, Barrie.

RodneyFord 06-30-2015 12:24 PM


Originally Posted by brustyrc (Post 12063318)
Very nice work as usual Rob, I'll follow this with interest, 'best, Barrie.

Hi Barrie nice to hear from you.
The interesting bits for me are the things that are done differently or in a new way.
These are:
The free form shaping using the profile gauge for symmetry (I got pretty close by eye)

Polyester mold with gel coat sprayed in with popcorn gun (I got a new compressor that will run continuously)

Engineered mold locating and joining system.

1mm Rohacell for the sandwich material in the finished fuselage.

My first decent size electric model. I might do my own contra gearbox, I mean how hard can it be!

drac1 06-30-2015 02:49 PM


Originally Posted by RodneyFord (Post 12063569)
Hi Barrie nice to hear from you.
The interesting bits for me are the things that are done differently or in a new way.
These are:
The free form shaping using the profile gauge for symmetry (I got pretty close by eye)

Polyester mold with gel coat sprayed in with popcorn gun (I got a new compressor that will run continuously)

Engineered mold locating and joining system.

1mm Rohacell for the sandwich material in the finished fuselage.

My first decent size electric model. I might do my own contra gearbox, I mean how hard can it be!

If it were easy, everyone would be doing it. Lol.

Nah, just kidding. Would be well worth having a go. I haven't seen an exploded view of one, but I think there would be a fair bit of work involved. I'm a first class machinist by trade, so would be very interested. Post plenty of photos and give a good description of what you do if you decide to try.

RodneyFord 06-30-2015 03:57 PM


Originally Posted by drac1 (Post 12063623)
If it were easy, everyone would be doing it. Lol.

Nah, just kidding. Would be well worth having a go. I haven't seen an exploded view of one, but I think there would be a fair bit of work involved. I'm a first class machinist by trade, so would be very interested. Post plenty of photos and give a good description of what you do if you decide to try.

The Adverrun looks quite achievable. Need to cut spur gears and make shafts but I am set up for that. The Brenner system is more elegant to my mind but needs a high level of machining.

RodneyFord 06-30-2015 03:58 PM

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Took the canopy off and lined the front and rear.

RodneyFord 06-30-2015 03:59 PM

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An issue with this type of pattern is the lack of rigidity. At the moment it is a bit of a banana by 4 or 5 mm. I will need to stiffen it up or anything could happen when I glass it. I have put the laser line on it here to see how it is. I think I will inset some spruce strips along the sides and hold it straight while the glue dries.


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