Building materials, covering

yogi94
Member
Member
Posts: 11
Joined: March 11th, 2010, 9:05 pm
Division: C
State: MI

Re: Building materials, covering

Post by yogi94 » February 8th, 2011, 7:28 pm

When we built a helicopter, we first used really light shopping bag covering as suggested on this forum. However, it didn't fly. When the covering was changed to paper (think wide-ruled, school paper) the time was about 30 seconds. The paper was much, much, heavier.. Any explanations?

jander14indoor
Member
Member
Posts: 1581
Joined: April 30th, 2007, 7:54 am

Re: Building materials, covering

Post by jander14indoor » February 9th, 2011, 6:36 am

I suspect more changed than just the covering to make it fly. Many have been successful with the light grocery bags.
Assuming otherwise equal, lighter ALWAYS beats heavier in flight. So something else must not have been equal.
Can you post pictures of both copters? Describe how they are the same/different. Overall weight of both? Rubber used? Winds? Etc...

Jeff Anderson
Livonia, MI

yogi94
Member
Member
Posts: 11
Joined: March 11th, 2010, 9:05 pm
Division: C
State: MI

Re: Building materials, covering

Post by yogi94 » February 9th, 2011, 11:19 am

It was the exact same helicopter, we just removed the plastic covering and put on the paper. The rubber was also the same.. 3/32, double looped, total weight about 4g +/- .25

The only thing that could have changed was the added weight from the paper.

jander14indoor
Member
Member
Posts: 1581
Joined: April 30th, 2007, 7:54 am

Re: Building materials, covering

Post by jander14indoor » February 9th, 2011, 2:00 pm

If the weights were that close, and nothing else changed when you recovered I'm REALLY surprised. The light plastic works, use it myself and seen MANY other teams do well with it.

Hmmm, how tight was the plastic? Only thing I can GUESS is it was loose and billowy? If so, may not have been as effective an airfoil as the paper. Only a guess.

Alternatively, did you wind the plastic covered helicopter the wrong way and the paper one the right?

So far you are presenting an interesting puzzle.

Jeff Anderson
Livonia, MI

yogi94
Member
Member
Posts: 11
Joined: March 11th, 2010, 9:05 pm
Division: C
State: MI

Re: Building materials, covering

Post by yogi94 » February 9th, 2011, 3:04 pm

I think it might have something to do with the plastic? It was rectangular and one of the sides was uncovered and the plastic wasn't the tightest. We wound both the same way.

User avatar
Kovu
Member
Member
Posts: 43
Joined: November 21st, 2010, 6:35 pm
Division: C
State: OH

Re: Building materials, covering

Post by Kovu » March 6th, 2011, 3:27 pm

Whenever we put mylar on it seems to not be as tight as it should be, any suggestions on how to make it tighter?
They say first place is a lonely place.
Unless you have a partner then it is one heck of a place.

User avatar
illusionist
Member
Member
Posts: 942
Joined: March 20th, 2010, 4:13 pm
Division: C
State: MI

Re: Building materials, covering

Post by illusionist » March 6th, 2011, 3:37 pm

Kovu wrote:Whenever we put mylar on it seems to not be as tight as it should be, any suggestions on how to make it tighter?
Here is one method (scroll down until you see it).
I use grocery bags instead of mylar (much easier, not much of a weight problem), and the way I do it is that I start at the outside edge of the rotor, and slowly lay down a section, ensuring that I pull it tight, make that section stick, and then do the next section of the rotor blade.
2012-2013 Building Event Captain
Rule 7d. "Event Supervisors are allowed to break any competitors' devices" -bearasauras

User avatar
chia
Member
Member
Posts: 558
Joined: January 13th, 2009, 5:09 pm
Division: Grad
State: IL
Location: Derse

Re: Building materials, covering

Post by chia » March 6th, 2011, 5:03 pm

Kovu wrote:Whenever we put mylar on it seems to not be as tight as it should be, any suggestions on how to make it tighter?
If you do use mylar, wrinkle up the piece you're going to cover with before you glue - it makes it a lot more manageable and easier to keep tight.
(avatar is by xamag)
Favorite events: Anatomy, Microbe Mission, Ornithology, Circuit Lab, Helicopter
NCHS '13
==>

jander14indoor
Member
Member
Posts: 1581
Joined: April 30th, 2007, 7:54 am

Re: Building materials, covering

Post by jander14indoor » March 7th, 2011, 3:49 am

Don't overdo tight, too much will distort that very lightweight frame you spent so much time getting right. A little looseness is OK.

Jeff Anderson
Livonia, MI

User avatar
Kovu
Member
Member
Posts: 43
Joined: November 21st, 2010, 6:35 pm
Division: C
State: OH

Re: Building materials, covering

Post by Kovu » March 7th, 2011, 3:20 pm

Okay, ill try some of those ideas we have a decent method just trying to make it better.
They say first place is a lonely place.
Unless you have a partner then it is one heck of a place.

Locked

Return to “Helicopters C”

Who is online

Users browsing this forum: No registered users and 1 guest