Our local low power group is doing an egg duration launch next month. The twist is that no parachutes are allowed (because that would make things way too easy).

I have been looking at helicopter recovery and maple seed recovery in particular. I came across the Cyclone, designed by Jonathan Mills at the University of Indiana. It's a very interesting design that separates into a booster and maple seed component. The booster unit tumbles, whereas the maple seed auto-rotates. I'm leaning toward this design because of its simplicity, even if I do end up with an eggy mess upon landing. The only concern I have is that this is a small BT-20 rocket, designed for 13mm engines. Also, it isn't designed to carry a payload, let alone one the size/weight of an egg.


Notes:
http://www.cs.indiana.edu/~jwmills/...cket.plans.html


Has anybody built an up-scaled version of a mapleseed rocket, large enough to return an egg to earth safely? What should I be thinking about here?

Autogyration - what you call maple seed recovery is generally called helicopter recovery by rocketeers. At the first TARC I saw one team try helicopter recovery on an egglofter, it didn't work well at the finals but it might be possible with work. There are numerous articles available on helicopters

__________________
Did the chicken really cross the road, or did the
road move beneath the chicken? Albert Einstein

You Can't break the laws of physics but they can break you. Christine McKinley


Dale Greene

Mentor, Penn Manor Rocket Club
VISIT SPAAR
2010 Calder Cup
The Old West
2009 Calder Cup

" Speaking the Truth in times of universal deceit is a revolutionary act. " George Orwell

Yes, there have been larger versions of this sort of rocket. You will need to make sure that you get the area of the blade the right size, and then becasue everything is bigger and more massy, you need to make sure that you construct it to handle the increased forces that the rocket will encounter, and not shred.

I think it would be fairly easy to convert this into an egg lofter by making the upper tube with the main blade into an "egg on a stick" type model. You'll have to deal with the fact that the egg capsule will be hitting the ground first as well as having some rotational speed- which means you'll have to make sure the egg is protects on all sides.

Sounds like a fun project though.

kj

Would it be possible to attach some kind of foam nosecone, or something that will collapse, to the front of the egg capsule? That way when it hits the ground, some of the energy can be absorbed?

__________________
Bob Harrington
NAR #62740 L1
AMA #46042
CMASS & RIMRA Member

Nice idea! I've considered the idea of a crumple zone of some sort, and a foam nosecone would fit the bill nicely.

Odd'l Rockets sells a kit version of the Cyclone. It's too small, as you noted, for use in carrying an egg.

I don't know how well the design would scale up, but it definitely is a contender for duration. On just an A motor, Odd'l's Cyclone takes a long time to come down and it drifts an amazing distance.

Scaled up, it might not be as effective, but I suspect the design will still work as well, if not better, than a traditional helicopter design.

-- Roger

You may find that you have to add a weight to the rotor to compensate for the extra mass of the egg.

Also if the event is being run under Pink Book rules, Eggloft Duration models aren't allowed to shed parts. If it's just a fun event, then that probabaly doesn't apply.

kj

In this contest, our entry is allowed to separate / shed parts (e.g. a booster that separates from the egg payload capsule, and is recovered separately).

Your idea of adding a counterweight to the tip of the rotor is interesting - I wonder if a larger rotor would have the same effect. I think the trickiest part of this is getting the seed to start spinning, rather than simply freefalling nose-first.

I'm hoping to prototype this over the weekend (time permitting, of course...). I'm definitely going to try some small counterweights and see if they're helpful.

From Wayne Hill's Rocketry Blog,
http://rocketry.wordpress.com/copte...covery-gallery/

Scroll down to the bottom for this picture reference.
Stuart Samuels - 800% Upscale Mapleseed (400% in background)

The Odd'l Rockets CYCLONE kit is smaller and too light to be used as an Egglofter.
I would think it would require a very large blade rotor to compensate for the weight of the egg.

Still, it's ideas like this that spur some great development.

Attached Thumbnails

 

__________________
Hans "Chris" Michielssen
Old/New NAR # 19086 SR

www.oddlrockets.com
www.modelrocketbuilding.blogspot.com
http://www.nar.org/educational-reso...ing-techniques/
Your results may vary
"Nose cones roll, be careful with that."
Every spaceman needs a ray gun.
Look out - I'm the Meister Shyster!

Wow... that is *awesome*!!! I'm feeling very inspired right now. Thanks for posting that!