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Old 05-01-2018, 10:13 PM
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Foam Board Biplane

Work remains crazy busy, but still have managed to get in some flying minutes now and then -- great therapy to give the mind a break..

Flew the Hacker Extra many times, but for a variety of reasons, it just was not providing the flying performance I needed. So, as one of my "twos" goals is two wings, decided to take a crack at a biplane. Moving on to a bigger motor, prop and battery, as well as a bit heavier to handle stronger winds vs calm days only.
Working between Real Flight, 3ds Max, Draft Sight, and having access to a small laser cutter, have been piecing together a design.

Biggest design aid BY FAR is Real Flight (the ONLY way to design a real world model IMHO). Made several wrong assumptions about making a biplane, such as-- for simplicity-- making large struts. Thought those would be easy to make, be strong, and act like wing tip plates. Learned that on this design at least, they play major havoc with the yaw axis. They are still wide in the 3d model, but are much narrower in the FBB physics. Prefer swept wings, so the FBB kind of borrows those from an Ultimate. Everything else is made for functionality and building ease, such as no split elevator or rear deck. So, with large wheels for good operation off grass, the FBB is rather short on bling and looks, but am hopeful it will be a good aerobatic trainer.

The real world model only exists so far as a card board mock up, putting scrap cardboard to good use. The mock up helps in finding mistakes or areas where it will make the final build easier, as well as an overall invaluable visualization aid. For example, the picture shows the third pass at making the fuselage. Still many details to work out, and will make more mock ups as needed. As changes are made, the RF version will be adjusted to match.

In RF, the physics seem to be promising. Intentionally overpowered, there is enough power to hover and still have a longer flight time (including setting realistic capacity values). Also has the rudder authority I'm looking for to make K.E. flight. Rudder actually has enough effect to do edge loops.

Apologies for the RF pix: Hovering requires attention on all 4 channels, and while I find it pretty stable in a hover, it still was not easy (as a hover newbie) to get it to stay stationary long enough to get to the Tab key... Would be nice if the pix could be snapped from an Inter Link switch..

Enjoy a great and safe week.
Attached Images
File Type: jpg FBB render1.jpg (303.7 KB, 14 views)
File Type: jpg FBB render 2.jpg (334.2 KB, 9 views)
File Type: jpg ScreenShot1525010592.jpg (404.0 KB, 13 views)
File Type: jpg ScreenShot1525010681.jpg (489.6 KB, 16 views)
File Type: jpg DSCN0697S.jpg (291.8 KB, 20 views)
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Old 05-02-2018, 07:55 AM
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Talking

Your back
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Old 05-02-2018, 09:19 AM
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help

I offer this, just for knowing:
I have designed more fomies than I can remember. I always designed on art poster size heavy paper. I made the box fuse, depron, until EPP came along. Was a no brainier. Six mil EPP has more lift than 3 mil dep. Bends, not breaking.
The yaw, to talk about, is roll coupling, which is the rudder effect because of the design of the model.
If you want a model that looks some real world plane, take a pick, model it, fly it a few times, then throw it in the TRASH! It will suck!.
If you want a model that, that makes you shake all over the first time you fly it, from absolute joy! Learn from what I can offer. All of my fave rate models, I have on word doc, and pdf, step by step, and temple ts, and art work stencles, filed .
#1 The thrust line has EVERY THING TO DO WITH IT. thrust line, and HS, the same line, very important.
#2 Wings same distance from thrust line.
#3 A lot sweap, hursts, hover, and loops.
#4 Must have a lot of ruder below HS, to corect rool coupling.
#5 Side area above and below the thrust line, determins the amount of rudder above and below the TL.
#6 Folks flying compotition, won't, MUST HAVE , very small side force generators, so they can use rudder, and still fly level knife edge, fun flying folks like a lot of side forece lift, because it makes them look good flying knife edge all around.
#7 Buy a gram scale, weigh EVERY THING, it will open you're eyes!
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Old 05-02-2018, 11:28 AM
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Hey.. It's the electric man !!! Cool plane.
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Old 05-02-2018, 11:45 AM
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Needs dihedral ↑↑↑↑
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Old 05-02-2018, 12:21 PM
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Cool help

FOAMIE MAN, to you! please.
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Old 05-02-2018, 12:59 PM
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this would be fun to have to fly in front of my house, in the court ... in real life ...
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Old 05-02-2018, 02:03 PM
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ttps://www.youtube.com/watch?v=muGVpAPM3BQ
https://www.youtube.com/watch?v=1eQygzG-pIQ
I still have my se5a too fly, someone needed my Stearman, more than me.
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Old 05-04-2018, 11:34 PM
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Thanks guys.

A few more adjustments this week (ok, did it all in one evening..).
Reduced the width of the struts. The top wing is a bit further forward than on the Ultimate the FBB wings are loosely based on, so the struts have more of a forward slant and it required a little creativity to smooth them into the length of the wing chords.

Fuselage height reduced a bit to match the real world mock up. That raises the top wing height a bit-- needed to be able to fit the ~2"x2" battery into the future top hatch. The 4" wheels now seem a bit large, but have a long way to go to worry about selecting a wheel diameter.

Still working on the cabane details, so for now have changed to two vertical sections.

Enjoy a great weekend and next week.
Attached Images
File Type: jpg FBB render 3.jpg (278.6 KB, 9 views)
File Type: jpg FBB render 4.jpg (402.4 KB, 10 views)
File Type: jpg DSCN0700.jpg (500.6 KB, 12 views)
File Type: jpg DSCN0719.jpg (497.8 KB, 11 views)
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Old 05-04-2018, 11:53 PM
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Is there going to be plans for your bipe? It looks great BTW!
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Old 05-05-2018, 12:32 AM
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Cool update and pictures, thanks
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Old 05-05-2018, 06:43 AM
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food

This was 9 years ago, when 3 mil Depron was the order of the day. The electronics were heaver back then. The plans did not last long, Depron was to brittle! The built up fuses went away, when EPP came in, because you could not sand the corners. The all up weight was about + 0r - 10 oz. with three cell.
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Old 05-07-2018, 07:35 PM
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Thanks technoid!

Kha'Zix: If the RW model flies as well as hoped, might post the DXFs on RC Groups. Next up is working with the mock up on getting the motor, battery, and ESC best positioned. May have to make some dimension changes, as the model is essentially being designed and built from the inside out. Might get a chance to spend some lunch time on that this week, as well as maybe firing up the Power32 for some initial testing with the new pack and ESC.

flex: Nice work! Great color trim.
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Old 05-12-2018, 12:30 AM
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Have more or less settled on the cabane strut design, so added it to the RF model.
Still getting some progress made on the RW model, with the first test fit of the center joint after the change to a dove tail and the slot width determined for the square CF rod to fit snugly.
Attached Images
File Type: jpg FBB render 8.jpg (70.3 KB, 8 views)
File Type: jpg FBB render 9.jpg (462.6 KB, 6 views)
File Type: jpg DSCN0721S.jpg (202.1 KB, 7 views)
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Old 05-12-2018, 12:41 AM
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Very nice FE, What`s cool, is that there`s a RW plane that goes with the RF version and/or visa versa, THUS, making this a very interesting project. . Can`t wait to see/read the end results. AND, It`s nice to see you`re posting more often than not, good to have you back.
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