Helicopters B

Locked
User avatar
1nxtmonster
Member
Member
Posts: 88
Joined: February 13th, 2014, 4:41 pm
Division: B
State: PA
Has thanked: 0
Been thanked: 0
Contact:

Re: Helicopters B

Post by 1nxtmonster » April 7th, 2014, 2:31 pm

For my region, they used an annoying gym with flags hang in all over the place. Our copter got broken when it hit a flag and the rotor broke :(
Image

helicpters_rule
Member
Member
Posts: 44
Joined: November 16th, 2013, 7:17 pm
Division: B
State: OH
Has thanked: 0
Been thanked: 0

Re: Helicopters B

Post by helicpters_rule » April 7th, 2014, 3:00 pm

lovescience wrote:If you are an Ohio team headed to States on April 26th and you do not think that the French Field House with its rafters, cross-breeze and 48 ft. ceilings are an ideal venue for true performance rather than a game of chance, please consider expressing that concern ASAP. It appears no one has suggested that the venue is not ideal and so a change of venue is not being considered. It would be great to have the venue moved somewhere with a lower, unobstructed ceiling to allow for everyones hard work to determine results. Please consider requesting a change, and soon.
i agree 100 percent. I know that that they have racquetball courts (https://sites.google.com/site/osurball/) and i am going to ask for the to move it there.

chalker
Member
Member
Posts: 2104
Joined: January 9th, 2009, 7:30 pm
Division: Grad
State: OH
Has thanked: 1 time
Been thanked: 40 times

Re: Helicopters B

Post by chalker » April 7th, 2014, 7:19 pm

lovescience wrote:If you are an Ohio team headed to States on April 26th and you do not think that the French Field House with its rafters, cross-breeze and 48 ft. ceilings are an ideal venue for true performance rather than a game of chance, please consider expressing that concern ASAP. It appears no one has suggested that the venue is not ideal and so a change of venue is not being considered. It would be great to have the venue moved somewhere with a lower, unobstructed ceiling to allow for everyones hard work to determine results. Please consider requesting a change, and soon.
Please see my post about this in the 'petition' thread:
http://www.scioly.org/phpBB3/viewtopic. ... 22#p257122

Student Alumni
National Event Supervisor
National Physical Sciences Rules Committee Chair

Somicvs
Member
Member
Posts: 4
Joined: March 23rd, 2014, 10:13 am
Division: B
State: MI
Has thanked: 0
Been thanked: 0

Re: Helicopters B

Post by Somicvs » April 9th, 2014, 7:07 pm

Can someone give me some times for helicopters for this year? Regionals we got 1:15. & first place. What did other regions get.

Buckstops
Member
Member
Posts: 32
Joined: April 28th, 2013, 6:14 am
Division: B
Has thanked: 0
Been thanked: 0

Re: Helicopters B

Post by Buckstops » April 9th, 2014, 7:41 pm

We took first with 1:55, but a JV team had a 1:58.
Buckstops
"Don't practice until you get it right. Practice until you can't get it wrong."
"Sometimes you win. Sometimes you learn"

TrueshotBarrage
Member
Member
Posts: 29
Joined: February 8th, 2014, 8:15 pm
Division: C
State: AL
Has thanked: 0
Been thanked: 0

Re: Helicopters B

Post by TrueshotBarrage » April 11th, 2014, 2:24 pm

Our helicopter isn't working. We've made it just like it is supposed to, but it leaves the ground for about 2 seconds and falls down promptly, for a total of about 5~10 seconds. We've noticed making the rubber band have more tension (as in a shorter length) made it improve by a couple of seconds, but we were expecting for it to go at least 1 minute with our design. :< Thank you for any suggestions and tips

(and yes, we've tried different varieties of numbers of winds)
2015 Regionals
It's About Time - 3rd
Compound Machines - 1st
2015 States
Bridge Building - 3rd

2016 Regionals
It's About Time - 1st
Air Trajectory - 1st

jander14indoor
Member
Member
Posts: 1584
Joined: April 30th, 2007, 7:54 am
Has thanked: 0
Been thanked: 1 time

Re: Helicopters B

Post by jander14indoor » April 11th, 2014, 3:29 pm

Need more info to help. Also look back up this string.
Describe design. Weight, number of rotors, weight, number of blades, pitch of blades, weight, size of motor (length and width), number of winds, torque.
Basics, assuming you have a reasonable design and weight you either aren't winding your motor hard enough or you don't have a thick enough motor. You need MORE POWER!!!
Shorter motor just reduced weight, makes it easier to fly.

Regards,
Jeff Anderson
Livonia, MI

TrueshotBarrage
Member
Member
Posts: 29
Joined: February 8th, 2014, 8:15 pm
Division: C
State: AL
Has thanked: 0
Been thanked: 0

Re: Helicopters B

Post by TrueshotBarrage » April 11th, 2014, 8:43 pm

3 bladed rotors on top and bottom, spinning opposite directions. Blades are like sectors of a circle. Slanted in a way that is similar to a space diagonal of a cube. About 3~4 grams for the entire helicopter, not sure. For weight, I really can't say but I don't think that is the problem. Wings are light enough, we are using mylar for the covering. We are using .140 rubber bands. We are winding it for more than 2 minutes with a battery powered winder. Thanks in advance for any help.
2015 Regionals
It's About Time - 3rd
Compound Machines - 1st
2015 States
Bridge Building - 3rd

2016 Regionals
It's About Time - 1st
Air Trajectory - 1st

chalker7
Member
Member
Posts: 612
Joined: September 27th, 2010, 5:31 pm
Division: Grad
State: HI
Has thanked: 0
Been thanked: 1 time

Re: Helicopters B

Post by chalker7 » April 12th, 2014, 5:15 am

Weight is the single biggest factor in Helicopters success, the entire flight is essentially a math equation balancing weight against thrust. As long as thrust is more than weight, you'll go up. If thrust is less than the weight, you'll go down. Even 0.1 grams above minimum weight can have a significant impact on your times because rubber motors do not provide that much torque, meaning the rotors are limited in their thrust. I would highly suggest finding the actual weight of your helicopter.
Also, I would suggest switching from an electric winder to a hand-winder. The precise number of turns on your rubber band is pretty important and by hand winding you can count them. Additionally, you get a "feel" for the motor, after winding them for awhile you start to learn how hard you can wind, when they are about to break, etc.
National event supervisor - Wright Stuff, Helicopters
Hawaii State Director

jander14indoor
Member
Member
Posts: 1584
Joined: April 30th, 2007, 7:54 am
Has thanked: 0
Been thanked: 1 time

Re: Helicopters B

Post by jander14indoor » April 12th, 2014, 9:03 pm

Let me second chalker7. With that description you aren't winding hard enough. If you are sure you are 3-4 grams the rest sounds like a reasonable design. It is capable of flying. That rubber should be thick enough.
Though the closer to 3.0 gm the better, PS, why can you only give a range, this is science, you should KNOW the mass, it is a CRITICAL parameter. If you haven't measured it, you might be surprised how heavy your helicopter is.

While I agree with chalker7 about hand winding, you can probably get the electric winder to work OK.
Do you lubricate your motors? If not, you must, you just can't get the winds into an unlubricated motor without it breaking prematurely. You don't need anything special, Armor-All or Son-of-a-Gun vinyl protectant from an auto supply store is fine.
Do you stretch wind? Many of the electric winders I've seen don't allow it. If not, you must. Stretch the motor to 3-4 times its relaxed length before you start winding. Put in about half the turns without moving. Last half of the turns as you slowly shorten the motor to the hook to hook length.
Do you have a counter on that winder? How many winds is two minutes? I suspect its not enough, the battery winders I've seen are slow. If not on the order of 1000 turns or more you aren't winding long enough. A motor that width 12-16 inch long loop should take 1000 to 1500 winds for a good flight.
If no counter, I suggest you wind 30 seconds and then manually unwind while counting turns. Then do the math to figure out how long it takes to wind 1000+ turns. Also, listen to the motor as you wind, does it slow down as you go. If so it will take longer than that test says.
Have you ever broken a lubricated motor? If not, you aren't winding hard enough. To win you WILL break motors.

So, back to my basic. Assuming the helicopter itself is reasonable (it sounds like it) you just don't have enough power. WIND HARDER! I'm always amazed supervising competition how many reasonable helicopters I see that get almost no time, hardly rise, but that are certainly capable of flying to the ceiling in most gyms. Almost always the problem is not winding hard enough.

Jeff Anderson
Livonia, MI

Locked

Return to “2014 Build Events”

Who is online

Users browsing this forum: No registered users and 1 guest