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Old Nov 14, 2012, 12:09 PM
Scale Modeler
Concordefan's Avatar
Canada, ON, Mississauga
Joined Feb 2006
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Just fantastic build, You are one of the very few rc modelers who could get the cockpit and nose profile right on the money!, most simply can't make them as they should be. I need to ask you, how did you managed to cut foam wing panels as a single piece with different trailing edge angles!!!, I would have cut 2 panels each wing due to this TE angle change!.....very interesting.

Are you going to add CF rods through the wing, at least from root to the OB engine pylon mounts, I would add if it was me building this model just so CF tubes can pick up all the load and they also act as spars in the wing section plus you can tie up wing main gears to these CF rods also...
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Old Nov 14, 2012, 09:17 PM
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United States, NM, Albuquerque
Joined Sep 2010
169 Posts
Quote:
Originally Posted by Concordefan View Post
Just fantastic build, You are one of the very few rc modelers who could get the cockpit and nose profile right on the money!, most simply can't make them as they should be. I need to ask you, how did you managed to cut foam wing panels as a single piece with different trailing edge angles!!!, I would have cut 2 panels each wing due to this TE angle change!.....very interesting.

Are you going to add CF rods through the wing, at least from root to the OB engine pylon mounts, I would add if it was me building this model just so CF tubes can pick up all the load and they also act as spars in the wing section plus you can tie up wing main gears to these CF rods also...
Thank you all for the compliments and help so far. If I didn't have all of your build methods to emulate I would probably just be folding paper.

Anyhow, answering questions. For the wing- I cut out the outline of each wing into 2 inch foam board. Then, I cut off the raked wingtip about 6 inches in. This gave me a rough basic wing design for which I used clary-Y foils printed on my tile program. The wingtip was then epoxied back on and sanded to shape. Not the quickest method but results were great after a bit of sanding. I embedded ~3/8" CF rod along the 1/3rd wing cord to about one inch from the end. Then I put an additional 1/4" rod at about half cord (see pictures). An additional small rod was placed near the wingtip to strengthen it a little. Let me know if you all think it is sufficient or if I should add more. As I watch videos from plane mounted cameras, the wingtips definitely flex a bit. The benefit to solid wing as I see it is easier to add control surfaces and other cutaway areas (retracts and additional servos). The difficult side is that with multiple servos and wires, you end up having to dremmel out multiple tracks and then fill them in.
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Old Nov 14, 2012, 09:27 PM
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demondriver's Avatar
United States, SC, Charleston
Joined Mar 2007
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Quote:
Originally Posted by rlebaron View Post
Thank you all for the compliments and help so far. If I didn't have all of your build methods to emulate I would probably just be folding paper.

Anyhow, answering questions. For the wing- I cut out the outline of each wing into 2 inch foam board. Then, I cut off the raked wingtip about 6 inches in. This gave me a rough basic wing design for which I used clary-Y foils printed on my tile program. The wingtip was then epoxied back on and sanded to shape. Not the quickest method but results were great after a bit of sanding. I embedded ~3/8" CF rod along the 1/3rd wing cord to about one inch from the end. Then I put an additional 1/4" rod at about half cord (see pictures). An additional small rod was placed near the wingtip to strengthen it a little. Let me know if you all think it is sufficient or if I should add more. As I watch videos from plane mounted cameras, the wingtips definitely flex a bit. The benefit to solid wing as I see it is easier to add control surfaces and other cutaway areas (retracts and additional servos). The difficult side is that with multiple servos and wires, you end up having to dremmel out multiple tracks and then fill them in.
Nice work inserting all the CF tubes into your wings & stabs. . .that's not easy.

Can't wait for more!
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Old Nov 17, 2012, 02:21 AM
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United States, NM, Albuquerque
Joined Sep 2010
169 Posts
So I had some time today and sanded down the wing box. I will say that I feel getting the correct appearance for the fairings has been the most difficult part and probably the least scale of the build but whatever, it's close. The horizontal stabs and rudder were also attached. Next will be some reinforcement for the rear fuse then starting with the wing control surfaces, pylons and retract installation.
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Old Nov 17, 2012, 05:20 AM
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United States, SC, Charleston
Joined Mar 2007
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Love the latest 747 Photos Rlebaron! She's coming along suberbly!
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Old Nov 17, 2012, 06:24 AM
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Joined Oct 2012
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o.O WOW !!! I'm impressed can't wait to see her in the air
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Old Nov 22, 2012, 10:22 PM
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United States, NM, Albuquerque
Joined Sep 2010
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A little update. I have redone the landing gear. The old gear was made primarily with round tube. It was very difficult to make sure that everything was square and level. I ended up redoing the main landing gears with square tubing and it was much easier. I also made the mains pivot in a scale type fashion. The wing mains are not quite there but I think it'll work fine and look nice on approach. Also finally got the stabilizers on and lined up. It's all moving along well. I am next planning to finish the wing unit including control surfaces, pylons and channeling all the wires.
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Old Nov 22, 2012, 10:24 PM
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Revised gear.
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Old Nov 22, 2012, 10:32 PM
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United States, SC, Charleston
Joined Mar 2007
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WOW Look'in truly amazing! . . . .she's really turning out fanatsic!
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Old Nov 23, 2012, 09:04 AM
KFC
Blue Foam Master!!!
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United States, KY, Hanson
Joined May 2007
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have you figured your CG, yet?
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Old Nov 23, 2012, 12:55 PM
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United States, NM, Albuquerque
Joined Sep 2010
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Originally Posted by KFC View Post
have you figured your CG, yet?
No I have not at this point. I appreciate the comment because I was going to ask if anyone had a website resource for CG calculation. I found one once that was fairly in depth (since the wing is not a basic design) but have not been able to track it down since.
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Old Nov 23, 2012, 02:40 PM
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Australia, QLD, Worongary
Joined Apr 2011
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Quote:
Originally Posted by rlebaron View Post
A little update. I have redone the landing gear. The old gear was made primarily with round tube. It was very difficult to make sure that everything was square and level. I ended up redoing the main landing gears with square tubing and it was much easier. I also made the mains pivot in a scale type fashion. The wing mains are not quite there but I think it'll work fine and look nice on approach. Also finally got the stabilizers on and lined up. It's all moving along well. I am next planning to finish the wing unit including control surfaces, pylons and channeling all the wires.
Make sure you make it look realistic by having small springs to tilt the landing gear trucks, with the front end sitting up.
FWIW with the correct pitch angle for landing all the main gear rear tyres all touch down on the pavement very close to the same time. The main gear struts on the real thing also have a good two metres travel from top to bottom.
(Ex-747 driver here)
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Old Nov 23, 2012, 03:57 PM
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United States, WA, Seattle
Joined Jan 2005
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Nice work! I appreciate that you didn't go all numbers crazy and just cut side and top, and just went nuts with sandpaper.. :O
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Old Nov 23, 2012, 04:44 PM
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United States, NM, Albuquerque
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Originally Posted by depronair View Post
Nice work! I appreciate that you didn't go all numbers crazy and just cut side and top, and just went nuts with sandpaper.. :O
Power sander, sanding blocks and paper. In retrospect, after the initial fuse was cut I should have sectioned it and power sanded the cross sections instead of trying to get it close then cut/coring it out. That would have saved hours- live and learn right? Gives me good ideas for the next project.
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Old Nov 23, 2012, 04:53 PM
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St.Catharines, Ontario
Joined Jan 2009
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Quote:
Originally Posted by BillzillaAus View Post
Make sure you make it look realistic by having small springs to tilt the landing gear trucks, with the front end sitting up.
FWIW with the correct pitch angle for landing all the main gear rear tyres all touch down on the pavement very close to the same time. The main gear struts on the real thing also have a good two metres travel from top to bottom.
(Ex-747 driver here)
well, the gear aren't really angled to let em all touch at roughly the same time. the gear are angled, so that there's minimal shock transfer to the airframe. if all wheels touch at the same time, shock waves get sent up into the airframe, without being absorbed by the gear itself. if you angle them and allow seperate touchdown events to take place, the impact gets transfered to the gear and rebounds, rather than going up through the legs and into the airframe. pretty simple and ingenious.
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