2019 Fantasy Aircraft Design & Build Challenge - Logan X-stream6 by FoamyDM

[FoamyDM]

Fantasy Aircraft are very... AWESOME. ...and typically hard to get to work. (for me.)

My son picked out a little foam rubber launched glider about as big as my hand before school ended, we both agreed it looked pretty cool.

Action Shot! of the IWA X-Stream 5:

Shudder effect shows two craft, it's that FAST!.

Before he spent the summer with his mother i asked if he would like to have Daddy try and build a big size RC one. He smiled a big grin, YES!

After the original crafts title and the inspiration, I will call this the FDM Logan X-stream 6 (for his age).

Now he's back and Daddy spent the second half of summer with other projects. This challenge is a great excuse to get moving on this project. The thing about this project is I know 2 things. 1. This one flies 2. Where it's CG is.
That two-legs up onto the horse. I spend some time this last week and worked up some plans. It appears an important part to this plane will be paying attention to apparent Angles of attack.

Finally, I came up with 3 sheets. This is an Alpha build, and if you are adventurous I welcome you to please try it with me. I will use these plans to build a glider version and test/confirm CG. and use it to work out servo locations.

BUILD PLANS
Sheet 1 - Alpha
Sheet 2 - Alpha
Sheet 3 - Alpha

Components:

• Pusher C-pack with 10x4.7 prop.
• 4-9g servos
• 2200 mAh battery,

Estimating weight of 320g. Right now I'm not sure where all the control surfaces need to be.
Rudder, and Ailerons of course, but the Elevator, it has no easy location. I have the plans printed, so building will happen this coming week!

I will update the plans and big step build pics here. detailed blog will be in posts below some choice pieces will be edited here.

BUILD Pics
Cutting:
See this post
Forming Wings:
See this post
Fuselage:
See This Post
Ready for maiden"
Ready in this post

Maiden Video:

Project Takeaways: (Stop Start Continue)
Take-away from the Alpha design:
The slots through the fuse made it far more fragile than it looked.
The cockpit and fuse shape was good.
The upper wing shouldn't have been turned down neg. AoA. but should have flat-ish angle. with almost rhomboid cross section (I'm thinking iron. @kilroy07 - fist bump)
As with all things, feedback is a gift, and I would love your thoughts, ideas, and advice.

What does all this mean? Time to re-design and rebuild.
Clark Y on the front and bottom wings, and the I will have to figure out something for the upper wing.
I will need to adjust the fuse/wing interaction.
I suspect Differential thrust with 1806 A packs would work well.

 

[Michael9865]

Looks like a cool and ambitious project.

 

[FoamyDM]

I carved out a few moments to cut out the planes, which have been staring at me for a while now.

I'm not sure why the pictures so grainy...but you get the idea.
I have a training trip next week and a scout-ful weekend so, If I don't make progress tonight, there may be little progress until a week from now.

I you are choosing to follow along at home. i noticed something is screwy with the primary wing hole. things are off from side to side by a foam board thickness.

 

[FoamyDM]

I just checked the CADD files.
The doubler pieces have the wing hole in the corrects place. This means the starboard hole need to move up from the bottom panel 1 foam board thickness. (3/16")

 

[FoamyDM]

I made some progress on this this weekend. Spent about an hour. This as far as I got...

I realized I definitely need to work something out better in the wings.
The slot for the top wing, and the taper in the bottom wing isn't needed. Also the doubler need to remove 3/16 from the outer edges, and cut off at the area where the rear inner paper is removed for the taper.
I think I will have to redo the wings. Not the shape, bit I made the spar almost twice as thick. I think I will cobble it and see how it glides. Dunno. It'll have to wait until after this week.

 

[FoamyDM]

I came back from my trip, looked at the plane (looking like the previous post) and thought... this needs a redo.
I am not happy with the way the wings shaped out. I like the Shape... more that they aren't folding the way I'd hoped. They feel 3/4 scale. They should be longer chord, and a bit thicker.

I'll try a redesign... maybe the top and bottoms will be one unit per side. with the Mid-wing tying in. time to redraw and print.

 

[Ventus]

This looks like something that will be extremely twitchy and hard to control in RC flight. And yes, quite fast, with high wing loading.

So I agree, the wings (or whatever these things are ) need significant enlargement, and I would also increase the span while you're at it. IMO, regardless of this, the probability of a unsuccessful maiden is very high with this one.

But I will say - it looks reallycool . I hope it flies.

 

[Ventus]

As a side note, with an unconventional design like this it might be a good idea to put it into something like XFLR5 then play with wing shapes, incidence, airfoils etc. and see what might work in terms of stability and lift efficiency etc... assuming it can actually properly calculate airflow over this kind of shape. There's bound to be a lot of strange interference going on between the wings/surfaces, they are bunched up very closely.

Or maybe start with a much simpler 'concept' build (egg. with a silhouette fuselage and flat airfoils) that can be tweaked until it flies properly, and only then build the real thing.

Otherwise I think it's really a crap shoot whether it will fly at all (not to be discouraging, I really like the idea, so I am kind of thinking aloud of ways to make it work somehow ).

 

[BrickPlane]

Even if the maiden is a crash and burn, this one looks fun!

 

[FoamyDM]

Updated, and printed... I will try tonight or tomorrow night.. should have an update on this build afterwards.

 

[FoamyDM]

Thanks guys. Remember this is a model that already glides well in toy form.... If I captured it well enough I suspect success.

 

[FoamyDM]

It does appear to be very complex aerodynamically, thank you for the link. I do hope it goes well, but I if not, i hope i get a good crash video. I will be following the chuck glider to confirm CG, then add a motor.

 

[FoamyDM]

I've managed to finish up the build.
I went outside and chucked it around. I think I found the CG. It flew pretty good.
The last pictures shows the CG marks.

 

[FoamyDM]

Finally installed servos and rods, while a friend of mine sim-ed.

Now it's time to throw in a pusher and see how it goes.

 

[FoamyDM]

I gave flight a whirl yesterday.

I have a rebuild in my future. I learned a few things

 

[rockyboy]

Learning is great progress!

Build, fly, crash, repeat - on these new experimental designs, even more so

 

[Michael9865]

There is a guy starting one of these over on RCGroups, https://www.rcgroups.com/forums/showthread.php?3249093-Xtream

 

[FoamyDM]

There is a guy starting one of these over on RCGroups, https://www.rcgroups.com/forums/showthread.php?3249093-Xtream

Cool, thank you

 

[FoamyDM]

Interesting pieces from the thread above.
His plane only has a lifting wing for the front. the others are flat parralel plates (parallel to the KFM wing used)

This is an IWA Internal Wing Aircraft using the Coanda Effect (see diagram below)

White/Research Paper
IWA Slideshow Link.

Lastly, elmagnificado, Built one and used Differential pusher Thrust on the mid wing for this bad boy. Which is smart as this configuration cancels out any torque roll a single engine yields.

What does all this mean? Time to re-design and rebuild.
Clark Y on the front and bottom wings, and the I will have to figure out something for the upper wing.

Take-away from the Alpha design:
The slots through the fuse made it far more fragile than it looked.
The cockpit and fuse shape was good.
The upper wing shouldn't have been turned down neg. AoA. but should have flat-ish angle. with almost rhomboid cross section (I'm thinking iron. @kilroy07 - fist bump)