Lifting Body Design

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Lentamental

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I am in the very early stages of designing a UAV glider to drop off a high altitude balloon similar to this project: https://www.members.shaw.ca/sonde/

I was considering using a rugged lifting body design rather than the usual fragile glider type design, given high speeds of the jet stream, and the possible rough landing in an unknown location.
The problem that I am facing is no matter how much I read, scouring the internet for anything lifting body related, I can find many designs NASA and such have used, but nothing on the general principles of making a lifting body work. I simply have no clue where to start. Once I have a basic design, I can trim from there, but I am kinda stuck without something to use as a base.

For reference, I am trying to have a cell phone, micro controller like an arduino, and a small video camera on board, so we are looking at a payload in the range of 1-2lbs.

If you have any links or can point me in the right direction, that would be greatly appreciated.
 

bobkrech

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A lifting body will not work well for this application. You need a shape similar to a U2 or the one you had on your reference to actually glide at high altitudes.

Go to https://www.aerospaceweb.org/design/scripts/atmosphere/ to looks at the atmospheric properties at 85 KFT. At that altitude 120 knots true air speed is equivalent to about 20 knots at sea level. While the air speeds at 30-40 kft may be high the loadings caused by them are not as high as you might think because of the reduced density.

Bob
 

WillMarchant

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You might want to go over to https://groups.yahoo.com/group/rocketboostgliders to ask this. Bob Parks hangs out there. Bob's been working on exactly these sorts of projects for Aurora Flight Sciences for a long time. He's done the "drop a UAV from a high altitude" project. And their Martian UAV project is apropos.
 

Lentamental

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Thanks for all of those links. I learned just how little I know...

I also learned, however, that I really don't need it to glide that well. I am looking for something more on the controlled fall side of things. Seeing as how it is going to be falling from 20 miles up, it, in rough terms, only needs a 1:1 glide ratio to have a 20 mile range. A longer range would be nice, but more importantly, in a 20 mile radius, there will be at least 1 good landing site.
Because of this, I was looking into the X-24 bug and HL-20, but they are nearly impossible to trim well.
I suppose what I am looking for is an inherently stable device that has a little bit of directional control as it plummets slowly back to earth.
I would of course have a parachute to slow it down further right before it lands, but until that point, it could be traveling quite fast.
 

bobkrech

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You might want to look at RC sailplanes with a fair amount of dihedral.

You also should be aware that you must comply with all FAA regulations concerning balloon flights and unmanned aircraft operations. It is highly likely that any flight of this type will require a written FAA waiver as it will be conducted in controlled air space.

You should also be aware of these websites.

https://diydrones.com/

https://diydrones.com/profiles/blog/show?id=705844%3ABlogPost%3A28583

https://diydrones.com/profiles/blogs/ardupilot-main-page

https://fmadirect.com/detail.htm?item=1489&section=20

https://www.sparkfun.com

Bob
 
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WillMarchant

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You need to check out some issues of the AMA magazine from last year. They're working with the FAA, DHS, etc to set up new rules for hobby, education, commercial, and government UAVs.
 

Ironnerd88

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If you buld an X-24 Bug without the fins, it is a lot easier to trim. I have flown a few of them, and hey do glide...mostly.

The issue with most lifting bodies is that they were designed for super/hyper-sonic flight. Since we are a little slower, we need to change our designs a little. Even then, the LB gliders are not going to have great performance... which makes them great for smaller fields.


I think I'll try this one. I have loved it since I first read about it back in the nineties.

https://www.wainfan.com/gliding.jpg

and

https://www.wainfan.com/topper.htm

AND... (I almost forgot)

https://www.currell.net/models/facet.htm

FMX4IF1.JPG


FMX4G6.JPG


FACETMOBILE%20FMX-4.jpg
 
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woohoo

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Im new to rocketry.
How would you find it?:confused:
 
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