#### blackbrandt

##### That Darn College Student
Hello,

As some of you know, I'm currently at UAH. Anyway, I'm in the rocketry club here, and our introductory challenge is creating a payload that gets lofted on a balloon to 700 feet and then release it.

We're allowed to use any form of descent mechanism OTHER than a parachute/parasheet and the max descent rate is 15 feet/sec.

Our plan on our team was to use a glider for descent. I'm just working on figuring out materials for the glider.

I have the idea down to one of the following three:
1. Foam gliders like Ari does in the B/G section on here.
2. Balsa/Basswood glider.
3. Lightweight wooden frame with nylon wings.

Does anyone have any experience with these? I'd just like some input.

Thanks!

#### XolveJohn

##### Well-Known Member
I fly small and big boost gliders, see my RumbleBee design in the Rocket Gliders section. I also fly electric planes.

Couple of problems. First, a half a LB is a huge payload. Might require a wingspan of six feet, chord of a foot. Calculate
the wing loading, and compare to a typical model plane! Second, releasing from a balloon does not give any forward velocity to glide. Or does the half LB include the glider weight?

Assuming it it radio controlled, you may need to do a dive to gain speed, then pull out. 700' is a decent altitude, but
not much room for error. Don't want to bonk someone on the head with it. Strange event for a rocket club.

Where is the rocket?

#### blackbrandt

##### That Darn College Student
I fly small and big boost gliders, see my RumbleBee design in the Rocket Gliders section. I also fly electric planes.

Couple of problems. First, a half a LB is a huge payload. Might require a wingspan of six feet, chord of a foot. Calculate
the wing loading, and compare to a typical model plane! Second, releasing from a balloon does not give any forward velocity to glide. Or does the half LB include the glider weight?

Assuming it it radio controlled, you may need to do a dive to gain speed, then pull out. 700' is a decent altitude, but
not much room for error. Don't want to bonk someone on the head with it. Strange event for a rocket club.

Where is the rocket?
The half pound is the weight of the entire "falling object". The payload itself is just a control board similar size to an arduino plus a few sensors.

It would not be radio controlled, I was talking about a passive glider.

It's also not just a rocket club, it's called the Space Hardware club. They do balloons, planes, rockets, satellites, etc.

#### XolveJohn

##### Well-Known Member
Well then it is not that hard. But transitioning from a dead stop to glide velocity will be a trick.

You need a trim change. Either a weight that slides back after a second or so, or a programmable elevator device.

Try just dropping a glider flat from a balcony somewhere. It will not begin to glide immediately. That is why we do hand tosses! The old classic HLG was interesting, we old rocketeers used some of their tricks.

Or you might hang the glider nose down, and have a little up elevator set up, but CG in right place for good glide.
It should transition to glide pretty fast. The simplest way I can think of to do this, no control junk.

Trim to circle, tiny bit of weight on one wingtip will do it. You can probably find a suitable foam bird at HobbyKing.

#### cerving

##### Owner, Eggtimer Rocketry
TRF Supporter
What would be REALLY cool would be to have the control surfaces hooked up to servos controlled by your Arduino, with a GPS feed so it "returns to home". A+ in my grade book...

#### blackbrandt

##### That Darn College Student
What would be REALLY cool would be to have the control surfaces hooked up to servos controlled by your Arduino, with a GPS feed so it "returns to home". A+ in my grade book...

None of us on the team have enough programming experience for that. I'm the programmer and I'm basically able to make the control board read data from a sensor and flash a light.

#### Nytrunner

##### Pop lugs, not drugs
Magic Umbrella:
Spring loaded radials that deploy when released? Stretching out whatever webbing or foil is allowed? (provided sheeting of Any kind isn't banned)

If there wasn't a max descent rate constraint, I'd be tempted to pitch an inverted saucer (Huygens style) with an ~F22 motor in the nose to fire at 50 or 100ft .

#### XolveJohn

##### Well-Known Member
A passive glider is simple. BTW, make sure it has generous dihedral. Some Eplanes, if they have ailerons, don't have any, and you will not have roll stability. You could make a double sized RumbleBee to do it. Plans are in the may/june Sport Rocketry.

TRF Supporter

#### georgegassaway

##### Well-Known Member
TRF Supporter

Ah, you are onto something there. But rather than Maple seed, a 3-bladed simple copter with some dihedral. No problems with trimming for glide.

More like this "Tasmanian Devil" copter rocket, with the blades glued fully open.

https://georgesrockets.com/GRP/Plans/Sport/Taz.html

But it would not need the rocket tube part. The three blades could be glued to each other, one end of each cut at 45 degrees, so when glued together with dihedral they would create an incidence angle between each for spin (I might have to glue some small pieces of scrap balsa to show what I mean, and it may be a bit trickier than I'm envisioning). Mount the payload within the recess.

Whole thing would be raised up pointing "nose down" so it would begin spinning shortly after release

Could be built out of three sheets of 3 x 36" balsa, 1/8" maybe thick enough, 3/16 certainly would be unless it was pretty heavy (crappy) balsa and risked being too heavy.

Critical thing...... add 2 to 4 ounce fiberglass cloth across the joints where the blade roots meet each other, as otherwise on landing the landing shock might cause the glue joints to break.

Although, could also add a spring, or simply some pool noodle foam (or pipe insulation foam) to the "nose", to act as a shock absorber.

Would come down way slow and with style.

Of course, Blackbrandt might just plain prefer....... a plane. But this would be so easy and reliable.

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#### Charles_McG

##### Ciderwright
I've played with rogallo/flexi wing gliders - but they are going to have the same 'starting at 0 forward speed problem'.

I like the idea of a foamy, nose down, with enough elevator to pull out of the dive (and a wingtip weight to make it circle), or the copter George is describing.

#### Crash-n-Burn

##### Well-Known Member
My vote is for maple seed design.

#### XolveJohn

##### Well-Known Member

RETROROCKET!

I guess probably dangerous, but could just have a rocket with an engine in the NOSE. Drop it, ignite at carefully calculated time, so burns out at maybe 50' high, then immed deploys streamer.

Or inspired by Space X booster recovery, come down slowly, long burn, low thrust. Maybe use the old Estes Vashon cold propellant engine, must be on Ebay. Perhaps a water rocket! Let's get engineering, folks. c:

#### K'Tesh

##### OpenRocket Chuck Norris Lifetime Supporter
TRF Supporter
Any chance for a catapult? That at the designated altitude the glider launches itself?

Another idea would have the wings retraced and deploy slightly after releasing. That way it could get some speed going before it tries to fly.

#### Lowpuller

##### Well-Known Member
Foam Glider with folded wings, spring loaded wings. Imbed the payload. Launch it using the ejection charge!

#### blackbrandt

##### That Darn College Student
Hey all!

Sorry for the delay in responding, I've been frantically backed up with school.

The rules say no pyrotechnics. Sorry :/

We ended up just going with an airbrake design. As one team member phrases it, it will look somewhat like the heat shield on the Apollo capsule.

#### K'Tesh

##### OpenRocket Chuck Norris Lifetime Supporter
TRF Supporter
Here's an idea... I know you've already got a plan...

CO2 cylinder(s) fills a very large bag, and the air resistance does the slowing.

#### Steve Shannon

##### Well-Known Member
TRF Supporter

RETROROCKET!

I guess probably dangerous, but could just have a rocket with an engine in the NOSE. Drop it, ignite at carefully calculated time, so burns out at maybe 50' high, then immed deploys streamer.

Or inspired by Space X booster recovery, come down slowly, long burn, low thrust. Maybe use the old Estes Vashon cold propellant engine, must be on Ebay. Perhaps a water rocket! Let's get engineering, folks. c:

Several years ago on Rocketry Planet someone was trying a rocket with a forward looking/forward mounted motor set to fire well before it reached the ground. I don't remember the details, but the problem is that aerodynamic stability disappears as airspeed disappears.

Steve Shannon

#### bobby_hamill

##### Well-Known Member
Matt

There was an article from the National Weather Service where they wanted to recover Weather Balloon Instruments called a "radiosonde" and reuse them thus cutting costs.

What they did was put the radiosonde in a small glider fitted with gps and attached the glider to a balloon.
The starting point was entered into the gps and when the glider was cut loose from the balloon the glider would backtrack to the starting point gps and go into a slow circle and descend back to the release point to be reused

Bobby

#### BABAR

##### Builds Rockets for NASA
TRF Supporter
Hey all!

Sorry for the delay in responding, I've been frantically backed up with school.

The rules say no pyrotechnics. Sorry :/

We ended up just going with an airbrake design. As one team member phrases it, it will look somewhat like the heat shield on the Apollo capsule.

Airbrake will work great, and accounting for wind, will come straight down