Why do spools fly?

[GRIFFIN]

[YOUTUBE]_lW8p8-y1K0[/YOUTUBE] I beg to differ, and i just entered it in the SNF competition

At the end you scream "YES!!"..........That was the result you were looking for......that was a success??? Next time aim it at a tree. Now that would be a success- T-P'n someones tree at the push of a button.

 

[Micromeister]

Sorry SD:
NOT yes! that was not a successful flight. it wasn't even a model rocket flight it was just a useless burning of a motor. Your TP roll was not stable, nor did it accomplish anything other then show that a C6 motor can in fact tumble a TP roll into the air, which could have been done any number of other ways with the same tumbling trajectory. Ya need to add at least one disc to the configuration for it to really work.

 

[ScrapDaddy]

At the end you scream "YES!!"..........That was the result you were looking for......that was a success??? Next time aim it at a tree. Now that would be a success- T-P'n someones tree at the push of a button.

I wanted it to go up, I set the bar pretty low, I was thinking 100 feet tops, I was right.

Micro, it flew up without burning or doing a crazy helix in the air, it was successful in my book.

"Any experiment that yeilds data was a successful one" - Adam Savage.

I was trying to see if a cylinder had the properties of a spool in flight.

 

[Micromeister]

I wanted it to go up, I set the bar pretty low, I was thinking 100 feet tops, I was right.

Micro, it flew up without burning or doing a crazy helix in the air, it was successful in my book.

"Any experiment that yeilds data was a successful one" - Adam Savage.

I was trying to see if a cylinder had the properties of a spool in flight.

To that end you may be able to claim some limited success as the answer was the same one EVERYONE on this list gave you. NO a cylinder does not have the properties of a spool.
You'll get the exact same results by Throwing the roll of TP in the air, using an inner tube, water balloon launcher or any number of other methods. the "cylinder" as you call it was completely unstable having no redeeming flight worthy characterists what so ever. 100 feet my rosy rear end, that didn't go more than 30 feet tops flip flopping all the way. Unstable is unstable, Add a disc either top or bottom you at least get the thing to fly straight for prehap 35feet LOL!!!

SD you do realize when we come down on you a bit harder then usual it's because we are REALLY trying to help you. Frankly if you were mine you'd have never had the chance to push that particular button, it could have ended very badly for YOU.....You could have been TP'ed.

 

[Rex R]

why? maybe the same answer as the bumble bee...brute force and ignorance. they don't know they are not supposed to fly .
rex

 

[Micromeister]

why? maybe the same answer as the bumble bee...brute force and ignorance. they don't know they are not supposed to fly .
rex

Exactly!
That's way I have a flying M85 Tank. With enough Thurst Anything will Fly LOL!!!!

 

[ScrapDaddy]

Exactly!
That's way I have a flying M85 Tank. With enough Thurst Anything will Fly LOL!!!!

I think this is going in my signature! :roll:

I just wanna know why a spool and a cylinder both produce base drag, but only the spool is stable.

 

[kramer714]

Scrap,

Back to basics, look at a cylinder and calculate the center of gravity vs the center of pressure. Now look at a spool with the same diameter as the cylinder, VERY different Cp.

next understand the difference between dynamic center of pressure and static. Don't worry about the details in the math, just understand the principal. Once you do that it isn't to hard to to figure out if something CAN be stable (WILL be stable takes a little math).

Been able to fly a
football (real football, Steve Young signature model, 4th and waaay long),
pizza (14 inch)
lots of saucers
beer bottle (rocket shaped like, not glass),
paint roller tube rocket
hamburger bun (yes a real hamburger bun)
mop (the mop was really cool to see go)
broom (mops work better)
pumpkin (plastic pumpkin filled with glow sticks that ejected at altitude)
and last weekend flew an 8" foam mushroom (on a G flew like a banshee)

All were stable. Not boasting just saying it isn't too hard to figure out if something will be stable before launching it. Want to fly a roll of TP you can make it stable, need help, ask,

Steps, a) Think, 2) plan, 3) build), 4)rethink 4a) convince someone else that it will work 5)launch.

Getting something off the ground doesn't make it stable.

I will go back and hide now..

 

[jim fustini]

I launched a scratch built spool once. on G-80T it was not pretty. I won,t get "Spooled" again. :roll:

 

[RocketRick]

Steps, a) Think, 2) plan, 3) build), 4)rethink 4a) convince someone else that it will work 5)launch.

Getting something off the ground doesn't make it stable.

I will go back and hide now..

I need to stop helping you with step 4a....



- Rick

 

[cjl]

Awesome picture


What kind of tubing was that?

 

[MarkII]

The recent posters have a point. Jumping on a trampoline does not give you the ability to fly, it just makes you ballistic. (You aren't flying, you are falling.) The same is true when you loft a simple cylinder shape with a model rocket motor. The fact that it isn't tumbling end over end doesn't mean that it is flying, except in the crudest sense. A totally unstable rocket will usually get kicked up into the air for a couple of seconds when the motor thrusts, too, before it flops back to the ground, but that would never be regarded as a flight by anyone's definition. An object that leaves the ground for a brief interval isn't necessarily thought of as flying during its period in the air.

 

[kramer714]

way to rat me out Rick.....

um, that one was my kids rocket... (points to 10 yr old in the next room) really it was.

Actually the Dancing Noodle of Doom flew better than that picture makes it look, take a look at https://www.flickr.com/photos/crayonrocketry/sets/72157624757153198/ find the series of picts Rick took. Believe it or not it continued going up after that wiggle.

The body tube was pool noodle, a bit bigger than the average ones, the fincan was a tubefin made from, you guessed it pool noodle, the nosecone was 1/2 of a foam football. There is 100g of nose weight to, um, help stability.

Stable, not so much, that is why it didn't make the stability list. The problem wasn't aerodynamics, it was natural frequency. Someone suggested to my kid (really it was his rocket) that he stiffen up the center, his answer was..why?

Cool to see, at ROCtober he plans to launch it at night with a sparky.

The kid is the skinny blond haired kid holding the noodle (without the fin can), My favorite picture is https://www.flickr.com/photos/crayonrocketry/4906206665/in/set-72157624757153198 look at the smoke trail!!

https://www.flickr.com/photos/crayonrocketry/4906218705/in/set-72157624757153198 is the Shroom of Doom before launch, now that on flew stable!

 

[GRIFFIN]

I have never really understood the fascination of the "spool" untill today.
I finished off a roll of wire at work the other day and figured I would give it a try.
I just took a section of 29mm motor mount tube and "2-part foam'd" it in place, stuffed a motor in it and set up the camera......I must say I was impressed. I used an Aerotech F-26 (removed the ejection charge) I didnt expect it to go as high (hench the street light and yes this was in front of my house- and yes oficer, this is a science project for school)

I just had a full day of high power launching the day before and somehow, a stupid spool still got the "rocket juices" flowin'.

watch the whole video, you will see the spool at the end of the flight at the top right hand side of the screen.

https://www.youtube.com/watch?v=tU9JTi9wu80

 

[kramer714]

the video is great!!!

Something bout the 'it looks like it shouldn't fly so well' is part of the fun.

Where do you launch HPR? I have a nephew in Palatine who would have fun seeing a HPR launch.

 

[GRIFFIN]

the video is great!!!

Something bout the 'it looks like it shouldn't fly so well' is part of the fun.

Where do you launch HPR? I have a nephew in Palatine who would have fun seeing a HPR launch.

Yea, we were lucky with the camera placement. We go to Bong in Wisconsin for the high power launch.