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Old 02-25-2015, 04:33 AM
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Quad Fan Delta

The next "in process" plane is the first venture into custom design-- almost. "Almost" means while not completely original, it is extensively modified from the original design. The plans were found on the internet, and the name of the original designer is unknown.

The following changes have been made:
  • Increase the wing span from about 3 feet to a more visible 6 feet.
  • Remove the glow engine and its pusher prop that fits inside a wing slot and replace with electric ducted fan power.
  • Replace the fixed trike gear with retracts, including full gear doors.
  • Keep the basic fuselage shape, but smooth out the transition into the wings.


Having never worked with a delta wing before, some internet searching was done to find the correct balance point. Learned about MAC calculations for a delta. Not shown in the render, but some thin polygons are positioned on the fuselage of where (according to MAC equation calculations) the balance area should be. That helps in correctly positioning the 3d model on 0,0,0 in max. True to the quality of RF, the plane flies well when balanced according to the math!

In wanting this model to be realistic if such a real world design was ever built, I looked at the common fan sizes for EDFs. The first pass was with 2 motors, but there wasn't enough thrust, without going to a diameter that just didn't look good. So, the design has changed to four smaller diameter EDFs.

With its slotted pusher design, the original fuselage was much shorter. Taking some (ok, many) designer liberties, the attempt is to extend and flow the fuselage back to about the wing TE.
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File Type: jpg QFD render 1.jpg (70.1 KB, 44 views)
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Old 02-25-2015, 09:18 AM
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Wow, very nice I'll be watching.
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Old 02-25-2015, 09:43 AM
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Thanks technoid.
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Old 02-25-2015, 11:47 AM
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Wow I can't wait for this one looks great!
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Old 02-25-2015, 12:54 PM
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Thanks Ron6234.
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Old 02-25-2015, 05:51 PM
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nice FE try a new side to Modeling and the Flight Physics in RF 8)
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Old 02-25-2015, 06:22 PM
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Thanks Doug.
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Old 02-26-2015, 07:20 AM
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That looks like a great model. One thing I would change though is the vertical stabilizer, I would just use one that size or make the two of the ones on there smaller.
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Old 02-26-2015, 10:58 AM
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A single large ducted fan in the center that is mounted in the fuselage wouldn't work? There would have to be air inlets cut out in the front and would change the model entirely but it could also be a completely different model too. I wish I could put down what I am picturing in my head because it looks pretty cool.
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Old 02-27-2015, 01:14 AM
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Quote:
Originally Posted by csgill75 View Post
That looks like a great model. One thing I would change though is the vertical stabilizer, I would just use one that size or make the two of the ones on there smaller.

Thanks csgill75.

Yes, the fins are on the large size, but that is how the original delta was (even if they did not need to be for flight performance??). Had not thought about changing them, so thanks for the idea. Nothing is in stone about them at this stage, so they may get resized-- or reshaped for that matter. Will probably stay with two, but may see how they looked angled. Also, their larger area will help with visibility when the delta is viewed from the side-- maybe that is why they were made that way..
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Last edited by Fly_electric; 02-27-2015 at 01:32 AM.
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Old 02-27-2015, 01:25 AM
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Quote:
Originally Posted by csgill75 View Post
A single large ducted fan in the center that is mounted in the fuselage wouldn't work? There would have to be air inlets cut out in the front and would change the model entirely but it could also be a completely different model too. I wish I could put down what I am picturing in my head because it looks pretty cool.
One large EDF probably would work, but there is just something XB-70 like that appeals to me about the under slung pods. Am going for keeping the basic shape per plans as much as possible, and smaller motors help with that. The 4 motors do sound really nice, and plan on adding the optional differential thrust control I've included in previous multi motor electrics.
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Old 02-27-2015, 01:50 AM
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Quote:
Originally Posted by Fly_electric View Post
One large EDF probably would work, but there is just something XB-70 like that appeals to me about the under slung pods. Am going for keeping the basic shape per plans as much as possible, and smaller motors help with that. The 4 motors do sound really nice, and plan on adding the optional differential thrust control I've included in previous multi motor electrics.
Goody Goody I love that differential thrust, it's so cool!
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Old 02-27-2015, 07:41 AM
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I was just thinking real world power requirements if someone was to build a full size version. 1 ducted fan would be simpler in real world flying than 4 when dealing with batteries, esc's etc. 4 do sound good 6 sounds better and would be more like the XB-70. Why not just model the XB-70? It's my favorite aircraft next to the B-58.

I pictured the Twin vertical stabilizer look angled both in and out and it would be nice either way.

Last edited by csgill75; 02-27-2015 at 08:26 AM.
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Old 02-27-2015, 11:17 AM
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.... Why not just model the XB-70? ....

It actually is on the "to do" list, but at this time is down a ways-- given the curvature of the Earth, it is not yet visible

The biggest challenge will be the main LG retract motion!
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File Type: jpg b-70-2.jpg (289.1 KB, 20 views)
File Type: jpg XB-70-4 (123).jpg (50.9 KB, 14 views)
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Old 02-27-2015, 03:53 PM
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If you need help with those just knock on my door FE.
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