Space Shuttle America - A Redux Scratch Build

[lakeroadster]

This is a great project, but I think you will need 3 pairs of eyes to keep track of it. Maybe paint the gliders different colors so you don't get both people watching the same one.
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For the next version, you can get the ramjets working. But then you'll need an altitude waiver. ;-)

Red and Blue Gliders,​

White booster and nose.​

 

[BABAR]

Flight test of gliders?
I’m guessing

 

[lakeroadster]

Flight test of gliders?
I’m guessing

"Space Shuttle America"... It glides, like a brick, with wings.​

 

[lr64]

Flight test of gliders?
I’m guessing

Such a pessimist! Is this a statement about gliders in general or these particular gliders?

I suspect even these can be made to glide if they are adjusted right. This may involve c.g. adjustment, twist, control surfaces, etc. Severely swept surfaces like this generally need a lot of washout (i.e. twist in the wing) to fly well.

 

[lr64]

A couple of interesting links about flying wings:
https://b2streamlines.com/winglinks.html
https://b2streamlines.com/Panknin/Panknin.html

I suggest somewhat more twist than what would give you an elliptical lift distribution. Of course, if I was doing this I might just use the TLAR method and a few crude gliders before messing around with the final version.

 

[ReynoldsSlumber]

Yeah, an optimized elliptical lift distribution is kind of out the window with a configuration like this. Really you're just trying to get it to do a trimmed glide at all.

Overall, what a lifting wing is doing is of course shoving/pulling air downward, and therefore it necessarily imparts a torque on the air. This is reacted out as a nose-down torque on the glider. The trick to being in trim for gliding flight is to counteract that with the right amount of nose-up torque, in the form of up-elevon at the aft tip extremities of the swept wings (or twist of the swept wingtip chord, as mentioned above). An alternative would be to angle the entire wing's trailing edge up a bit all along its span, like on that classic Space Shuttle America, to approximate what's known as a low pitching moment or "reflexed" airfoil. Or some combination of the two techniques.

Here's a diagram I made recently to go with a "Jetfire"/"VF-1S Valkyrie" tailless paper glider model:*

Note that the tailless plane has the added burden that the wing's center of lift (pressure) has to be behind the CG, for basic static stability. With a tailless plane, it's like someone leaning forward at a constant angle on a Segway or electric uni-wheel while traveling at a steady speed: the rider is balanced at that angle by the motor torque.

Here you can see the upturned wing trailing edge, most prominently aft toward the swept tips, plus in this case the body flap helping out with more up-elevator:

Previously I had tried to trim the glider with just the body flap, and it didn't work. It needed that reflexed wing trailing edge.

* Per the link, credit goes to some kind R/C aircraft folks in Japan for reminding me about the need for a low pitching moment airfoil for that project.

 

[BABAR]

Such a pessimist! Is this a statement about gliders in general or these particular gliders?

LOL. THESE particular gliders.

I was thinking that to get any stable glide at all in gliders this size made of plywood would (or wood) be outstanding.

Also if I recall the Lake-Man doesn’t do club launches, so a three part return with two long duration gliders and not a lot of spotters would not be….optimal.

If it were mine, and the two gliders went into a stable glide orientation with a prompt but safe descent speed which dropped them undamaged relatively close to the pad, I’d call it an absolute win.

I’m all for long duration glider flights for rocket-gliders (1 piece) or boost gliders (2 pieces.). Unless I am at a club launch with a big preferably flat field and a lot of spotters, once the glider number exceeds unity, duration is no longer as desirable a feature to me.

 

[BABAR]

"Space Shuttle America"... It glides, like a brick, with wings.​

Just for fun would like to se @burkefj build and fly a brick shaped rocket.

I mean, if you can fly a Klingon, Masonry should be easy!

 

[lr64]

Babar,

I can see the problem if there aren't enough eyes, but if there are, it might be fun. Kind of a team effort craft.

When you say "a glider this size", are you saying it's harder because it's big, or it's harder because it's small? If the wing loading is high, the glide may be fast, but that's no reason for it to be less stable, this side of Mach 0.6 or something. If the wing loading is low, that can be made to work, too. The bigger and/or heavier model is likely to have a flatter glide, even if it has a somewhat higher sink rate, because drag coefficients tend to be less at higher Reynolds numbers,.

I have had gliders with stable, hands of the radio (or free flight) with weights from maybe 8 grams on up (not counting the paper airplanes) to maybe 60 ounces. Come to think of it, I think one of them was more like 80 ounces. Spans from 8 inches (Fliskits Nanite, slightly modified) to 120 inches or more. The Nanite glided far too well, so I didn't have it for very long.

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Mr. Slumber,
Another thing that goes on, when wings are swept, is spanwise flow that screws up the angle of attack. A swept wing will have a bit of upwash at the tip, giving it a higher angle of attack, unless it's given washout (twist) to counteract the problem. Too much taper does the same thing. And if there's a lot of twist, then it's only right for one coefficient of lift, corresponding to stable flight at one particular speed. If one is really clever, it may be possible to make a wing that untwists itself at high speed. But that's tricky. It may be easier and more reliable just to use another gram of propellant.

A guy who just retired from NASA named Al Bowers is really into this stuff. Depending on just how deep you want to go down the rabbit hole, you might look into the Prandtl Project. Or his lectures to the Experimental Soaring Association, which can be found on Youtube.

 

[lakeroadster]

Ready for some color....

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[burkefj]

Just for fun would like to se @burkefj build and fly a brick shaped rocket.

I mean, if you can fly a Klingon, Masonry should be easy!

This was close

 

[BABAR]

Ya know, a stick of butter with wings would be a ButterFly!

I figure eventually you will have created every fighter plane built or imagined and will have to look for other ideas....

 

[BABAR]

Ready for some color....

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You already have this one well planned out, but looking at your nilboG, rear eject would be an easy way for glider separation. You kind of have mini launch rods sticking forward from the tail of the booster, at apogee the chute comes out and jerks the booster backwards and the gliders slide forward off the rods.

 

[lakeroadster]

View attachment 638776

You already have this one well planned out, but looking at your nilboG, rear eject would be an easy way for glider separation. You kind of have mini launch rods sticking forward from the tail of the booster, at apogee the chute comes out and jerks the booster backwards and the gliders slide forward off the rods.

Kind of tricky to do with the gliders tucked into the fuselage. Interior space is at a minimum to make a rear eject pod. Maybe have the chute stored in the ramjet tube?​

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Rear eject would have been cool though.​

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PS: Do you really build "rockets" for NASA?​

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[lakeroadster]

Paint

Shot some color... Red, White and Blue.​

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I had to use 2x for the blue... the Rustoleum Stops Rust Blue was too "Powder Blue Prius" for my taste.​

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