3D printed Lifting Body Chuck Gliders

telnar1236

Elite member
I was recently talking about lifting bodies with a friend and decided to 3D print one. It turned out a lot better than I expected and can actually glide decently well so I figured I would post the stl files here. It can be a bit hard to get in trim (by gently twisting the two outer stabilizer surfaces like elevons) but once trimmed it's great. I have included both the initial version I created and the refined version which generates more lift and glides better but is a bit harder to trim. Both were printed with the nose vertical in LW PLA with an infill of 2% and a wall thickness of 2 layers. The version 2 which is the heavier one weighs in at just 4 grams.
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  • Lifting Body 1.stl
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  • Lifting Body 2.stl
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telnar1236

Elite member
Be fun to air drop one over the field!
It's not quite stable enough in the glide for that yet. If you get it to go, it flies great, but the stabilizers stall before the fuselage, so if starts off at a high angle of attack, it never recovers. I'm working on a V3 to fix that issue, though.
 

telnar1236

Elite member
It's on the printer now. Gonna start the smoke generator thingy after this.
After some experimentation, I'd definitely recommend adding some nose weight. It makes it a lot easier to trim. Otherwise, just watch out for the stall. I'd recommend throwing gently and slightly down to make sure it stays stable.
 

SSgt Duramax

Junior Member
After some experimentation, I'd definitely recommend adding some nose weight. It makes it a lot easier to trim. Otherwise, just watch out for the stall. I'd recommend throwing gently and slightly down to make sure it stays stable.
I discovered that! It is probably exacerbated by the fact I printed it in PLA+. I am going to drop them off my plane. I was tossing it around the front yard on the way out to the car to work today. I got it mostly trimmed out, but noseweight is a must. I'm going to print another one in either red or lime green. Maybe I can just design some in there.
 

telnar1236

Elite member
I discovered that! It is probably exacerbated by the fact I printed it in PLA+. I am going to drop them off my plane. I was tossing it around the front yard on the way out to the car to work today. I got it mostly trimmed out, but noseweight is a must. I'm going to print another one in either red or lime green. Maybe I can just design some in there.
Nice! Let me know how it goes. I might be trying to do that soon myself.

My thinking on nose weight was to print the aircraft as two parts and print the nose with a higher infill. I'm surprised they fly at all in normal PLA since they don't exactly have much lift to start with, but I'm glad to hear you got it trimmed.
 

SSgt Duramax

Junior Member
Nice! Let me know how it goes. I might be trying to do that soon myself.

My thinking on nose weight was to print the aircraft as two parts and print the nose with a higher infill. I'm surprised they fly at all in normal PLA since they don't exactly have much lift to start with, but I'm glad to hear you got it trimmed.
The glide ratio is less than stellar, but I figured if I got my UAV up to 40-50 mph or so and let it fly, it would go a ways.

Actually, I think I'll break out the LW-PLA. They don't take too long to print, and I could print another part out of it anyways.
 

telnar1236

Elite member
New parts for the version 3 lifting body glider. It incorporates a number of aerodynamic refinements and is much better than either of the initial two designs as well as being about twice the size. The back section is printed in LW PLA as light as possible, while the nose is printed in normal PLA as heavy as possible. Trimming is accomplished the same way as with the previous two designs, but you can now isolate roll using the two more nearly horizontal stabilizers. The row of tiny fins at the back also prevents the unstable stall of the original designs. Depending on how it is printed, it might still need a bit of nose weight, but nowhere near as much.
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telnar1236

Elite member
Some actual pictures since I forgot to take them for my earlier post (you can see the scrape marks from my testing on the nose). Where the previous two versions can glide ok, this new version is getting into the kind of performance where I'm seeing 30-40 ft glides on a good hard throw
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SSgt Duramax

Junior Member
Some actual pictures since I forgot to take them for my earlier post (you can see the scrape marks from my testing on the nose). Where the previous two versions can glide ok, this new version is getting into the kind of performance where I'm seeing 30-40 ft glides on a good hard throw
View attachment 221965 View attachment 221966
Dangit! I just unloaded the LW-PLA. I'll put it back in though later.

I see what you meant about those other ones stalling. The tail just kind of drops, then they wallowed around before going in a spin. I managed to drop one off my plane today, and from what I could tell it looked cool for about 5 seconds then it started tumbling once it lost speed.

I'll give one of these a shot and see how it works.
 

telnar1236

Elite member
Dangit! I just unloaded the LW-PLA. I'll put it back in though later.

I see what you meant about those other ones stalling. The tail just kind of drops, then they wallowed around before going in a spin. I managed to drop one off my plane today, and from what I could tell it looked cool for about 5 seconds then it started tumbling once it lost speed.

I'll give one of these a shot and see how it works.
The newest version solves that problem with the stall. I needed 5 grams or so of extra nose weight (glued in between the nose cone piece and the main section) but I was able to get it to achieve a stable glide slope.
 

telnar1236

Elite member
I wonder how well this would go scaled up?
The larger you make it, the better it will fly (to a point) so long as you can continue to keep weight down. The main reason I scaled it up between the first two versions and the third was to increase the Reynolds number which results in the flow staying attached better. It's the same reason the sides go to sharp edges instead of rounded as on the previous two models.
 

telnar1236

Elite member
I recently found a bunch of public aerodynamic data from the X-24A lifting body as well as some documentation on the SV-5J, a variant of the X-24A meant to be powered by a jet engine that was built but never flew (the test pilot refused to try to fly it). I had been considering attempting an EDF powered build, but was never able to figure out inlet placement since the lift is so dependent on the exact shape of the fuselage being maintained. However, for the X-24A, the body operates more like a conventional wing, so the inlet can be placed below the body with few issues as was done on the SV-5J. In addition, the X-24A has by far the most complete set of aerodynamic data for any lifting body design including extensive wind tunnel data from an 8% scale model which is close enough to the 1/12 scale models that I like to build to ensure dynamic similarity removing any need for analysis on my end. Unfortunately, the X-24A design performs a bit worse than my 2nd lifting body design, but as a positive, the aerodynamic center is much further back making it much easier to achieve CG.

Before building an RC model, I wanted to build a chuck glider to make sure that gliding flight was achievable. This is the largest lifting body I have yet constructed at 12" long and 113 grams. The glider is 1/2 the scale of the 1/12 scale model I intend to build. As expected it is a worse glider than my version 4 lifting body, but it is a lot more stable. The two back sections are printed in LW PLA with a 2 layer wall thickness and 3% infill while the nose is printed in normal PLA with a 2 layer wall thickness and 20%-30% infill (infill should be adjusted so that the CG is between 53% and 58% of the length of the plane, not including the tail surfaces). My CG was a bit far forwards at 49% of the length so added balsa flaps to the trailing edge to help the aircraft pitch up which may have also contributed to the worse glide performance. Trim is performed in the same way as for the version 1 and 2 aircraft.


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  • 1-2 scale glider Front.stl
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  • 1-2 scale glider aft.stl
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  • 1-2 scale glider Nose.stl
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telnar1236

Elite member
A quick update on a few things mentioned about the newest lifting body design.

First, the aircraft performs much better when the CG is set to 57-58% of the length. After adding enough tail weight I could get it to achieve a glide slope almost as good as the previous version.

Second, while it is possible to trim the lifting body for level flight with just the stabilizer surfaces included in the STL files, the balsa flaps in the pictures in my previous post are extremely useful and much more effective. With the balsa surfaces I could trim the lifting body for turning flight (only possible throwing from the top of a hill) while without them, the adverse yaw from the V-shaped stabilizers made turning flight very difficult to trim for.
 

empa_fabian

New member
Thanks for the amazing design!
I'm currently working on a lifting body design that I would like to deploy using a quadrotor.
For that, I wanted to implement some changes to your version 3 design.
Would it be possible to receive the editable CAD files?
 

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telnar1236

Elite member
That print looks great. Definitely way sleeker in black than in the natural PLA. Here is the Fusion 360 file. I look forward to seeing what you do with it.
 

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  • Lifting_Body_v3.zip
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Gambit9m

New member
I was recently talking about lifting bodies with a friend and decided to 3D print one. It turned out a lot better than I expected and can actually glide decently well so I figured I would post the stl files here. It can be a bit hard to get in trim (by gently twisting the two outer stabilizer surfaces like elevons) but once trimmed it's great. I have included both the initial version I created and the refined version which generates more lift and glides better but is a bit harder to trim. Both were printed with the nose vertical in LW PLA with an infill of 2% and a wall thickness of 2 layers. The version 2 which is the heavier one weighs in at just 4 grams.
View attachment 221759 View attachment 221760
Could you make files of these without the winglets?