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Author Topic: Wright Stuff for 2017-2018  (Read 457 times)
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Little-Acorn
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« on: September 01, 2017, 05:45:08 PM »

Hi, all. I'm a newcomer to Science Olympiad, my son has just entered the 6th grade (Middle School) and they have an active program. I used to build rubber-powered models when I was about his age (and that was a LONG time ago, Sleek-Streek days), and saw a few incredibly ultralight indoor models (<1 gram, >24-inch span, microfilm) tho I never built one of those.

Now I'm putting together a plane that would have (I think) qualified for 2016-2017 Wright Stuff, though I'm not a student of course. Lightest power plane I've ever done. Doing it mostly to get a feel for common problems, design issues etc. I might wind up coaching one of our school's teams, and I'd like to at least have a rough idea of what I'm doing so I can (pretend to) teach others.

Has anybody seen any info on what the 2017-2018 rules for Wright Stuff will be? I'd rather build to that spec, of course, but haven't seen a word. When are the 2017-2018 rules supposed to come out?
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frash
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« Reply #1 on: September 01, 2017, 10:28:03 PM »

Someone somewhere posted that 2017-2018 Wright Stuff rules would be posted on Sept 5, I believe.

Fred Rash
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JasperKota
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« Reply #2 on: September 01, 2017, 11:16:52 PM »

Different from previous Science Olympiad years, Frash is correct, the rules will be available online free on September 5th, I heard it's around 9 am central time. You'll need to make some sort of account on soinc.org, just to confirm that you're part of a team though I believe. The easiest way is probably to ask the school's coach for a copy of the Wright Stuff rules.
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Little-Acorn
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« Reply #3 on: September 05, 2017, 02:11:14 PM »

You were correct. They just posted the 2018 Wright Stuff Rules, which they say are free to the public. Here they are:

http://api-static.ctlglobalsolutions.com/science/SO_B_2018FINAL.pdf (I hope that link works)

The Incredible Shrinking Airplane strikes again. Many dimensions are smaller than last year's, presumably so that people cannot simply re-use last year's airplane.

Minimum weight (excluding rubber motor): 7 grams
Maximum rubber motor weight: 1.5 grams
Maximum span: 40cm
Maximum chord: 10cm
Maximum stabilizer span: 20cm
Maximum stabilizer chord: 7cm
Two-blade propeller, maximum diameter: 14cm

The text:
____________________________________

Science Olympiad
2018 Rules

The Wright Stuff
Released Sept. 5, 2017

http://api-static.ctlglobalsolutions.com/science/SO_B_2018FINAL.pdf

1. DESCRIPTION: Prior to the tournament teams design, construct, and test free flight rubber-powered monoplanes to achieve maximum time aloft.

A TEAM OF UP TO: 2    IMPOUND: None    EVENT TIME: 8 minutes

2. EVENT PARAMETERS:

a. Teams may bring up to 2 airplanes, any tools, and their flight log.

b. Event Supervisors will provide all measurement tools and timing devices.

3. CONSTRUCTION PARAMETERS:

a. Airplanes may be constructed from published plans, commercial kits and/or a student’s design. Kits must not contain any pre-glued joints or pre-covered surfaces.

b. Any materials except Boron filaments may be used in construction of the airplane.

c. Total mass of the airplane throughout the flight, excluding the rubber motor, must be 7.00g or more.

d. The airplane must be a monoplane (one wing)and the horizontally projected wingspan must not exceed 40.0 cm. The maximum wing chord (straight line distance from leading edge of wing to trailing edge, parallel to the fuselage)of the wing must be 10.0cm or less. The maximum horizontally projected stabilizer span is 20.0cm. The maximum allowable chord of the stabilizer is 7.0cm.

e. The propeller assembly may be built by the participants or purchased pre-assembled. It may include a propeller, a shaft, a hanger, and/or a thrust bearing. The propeller must be a single two-bladed propeller with a maximum diameter of 14.0 cm. Variable-pitch propellers that include mechanisms to actively change the blade diameter or angle must not be used.

f. A rubber motor not to exceed a mass of 1.50g, including any attachments such as O-rings, must power the airplanes. It will be massed separately from the airplane. Motors may be lubricated before and/or after check-in.

g. Participants may use any type of winder, but electricity may not be available.

h. The airplane(s) must be labeled so that the event supervisor can easily identify to which team it belongs.

i. Students must be able to answer questions regarding the design, construction, and operation of the device per the Building Policy found on www.soinc.org.

4. THE COMPETITION:

a. The event will be held indoors. Tournament officials will announce the room dimensions (approximate length, width and ceiling height) in advance of the competition. Tournament officials and the event supervisor are urged to minimize the effects of environmental factors such as air currents. Rooms with minimal ceiling obstructions are preferred over very high ceilings.

b. Once participants enter the cordoned off competition area to trim, practice, or compete they must not receive outside assistance, materials, or communication. Only participants may handle aircraft components until the event ends. Teams violating this rule will be ranked below all other teams. Spectators will be in a separate area.

c. During inspection, each team must present a flight log of recorded data. Data must include 6 or more parameters (3 required and at least 3 additional) for 10 or more test flights prior to the competition. The required parameters are: 1) motor size before windup, 2) number of turns on the motor or torque at launch, 3) flight time. The team must choose 3 additional data parameters beyond those required (e.g. turns remaining after landing, estimated/recorded peak flight height, the motor torque at landing, etc.).

d. At the event supervisor’s discretion:
i. Multiple official flights may occur simultaneously according to the Event Supervisor’s direction.
ii. Test flights may occur throughout the contest but must yield to any official flight.
iii. No test flights will occur in the final half-hour of the event’s last period, except for teams that declare a trim flight during their 8-minute Flight Period.

e. A self-check inspection station may be made available to participants for checking their airplanes prior to check-in with the event supervisor.

f. Participants will present their event materials (airplanes, motors, and logs) for inspection immediately prior to their Preflight Period.

g. All motors that meet specifications will be collected at check-in and will be re-issued to the team only for their Preflight Period and 8-minute Flight Period. Time taken during the Preflight Period will impact a team’s final score (see 5.b.). Timers will follow and observe teams as they are winding their motors. Event supervisors are strongly encouraged to return flight logs after inspection.

h. A teams’ Preflight Period ends with their first flight, trim or official, which starts their 8-minute Flight Period or if 9 minutes passes after their motor has been returned, whichever comes first.

i. Any flight beginning within the 8-minute Flight Period will be permitted to fly to completion. Participants may make adjustments/repairs/trim flights during their official 8-minute Flight Period. Before their launches, participants must indicate to the Timers whether a flight is official or a trim flight. A flight is considered official if a team fails to notify a Timer(s) of the flight’s status. Teams must not be given extra time to recover or repair their airplanes.

j. Teams may make up to a total of 2 official flights using 1 or 2 airplanes.

k. Time aloft for each flight starts when the airplane leaves the participant’s hand and stops when any part of the airplane touches the floor, the lifting surfaces no longer support the weight of the airplane (such as the airplane landing on a girder or basketball hoop) or the supervisors otherwise determine the flight to be over.

l. Event supervisors are strongly encouraged to utilize three (3) timers on all flights. The median flight time in seconds to the precision of the device used is the official time aloft.

m. Participants must not steer the airplane during flight.

n. In the unlikely event of a collision with another airplane, a team may elect a re-flight. The decision to re-fly may be made after the airplane lands. Timers are allowed to delay a launch to avoid a possible collision. The 8-minute Flight Period does not apply to such a flight.

o. The supervisor will verify with the team the data being recorded on their scoresheet.


5. SCORING:

a. The base score is the Team's longest single official flight time. Ties will be broken by the longest non-scored official flight time.

b. Once a team has been re-issued their motors, prior to their 8-minute Flight Period, a timing official will start a Preflight Period stopwatch. If their first airplane flight, trim or official, is launched within 3 minutes of the return of motors a 5% bonus will be added to the base score. If the 8-minute Flight Period begins between 3 minutes and 6 minutes, no bonus is awarded. If the 8-minute Flight Period begins after 6 minutes, 10% will be deducted from the base score. After 9 minutes have passed since the return of motors, the 8-minute Flight Period will start.

c. A bonus of 10% of the flight time will be added to the flight time of an airplane that has the surface of the wing between at least 2 ribs of the leading and trailing edges or at least one of the wing tip fences completely marked with black marker or black tissue. If no ribs are present, the whole surface must be black.

d. Teams with incomplete flight logs will have 10% of their flight time deducted from each flight.

e. Teams without flight logs will have30% of their flight time deducted from each flight.

f. Teams that violate a rule under "CONSTRUCTION" or "THE COMPETITION" that does not have a specific penalty will be ranked after all teams that do not violate those rules.

Recommended Resources: The Science Olympiad Store (store.soinc.org) carries the Wright Stuff CD and Wright Stuff Video; other resources are on the event page at soinc.org.

THIS EVENT IS SPONSORED BY THE ACADEMY OF MODEL AERONAUTICS

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Bredehoft
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« Reply #4 on: September 05, 2017, 02:33:52 PM »

a seven gram plane with a max projected span of 15.8" and a max chord of 4" using a max diameter 5.5" prop.

This is not hard to do - many, many NoCals fit this description, as do many stick models, such as the Blatter 40.

In fact, the Blatter 40 may just be a very competitive model; mine routinely gets well over 2 minutes with the specified prop assembly and a loop of 1/16" rubber (although it is probably less than 7 grams).  An estimated length of 1/16" rubber that weighs 1.5g would be roughly 36".  Brought up to 7g, it might require a slightly thicker motor, but still - that is plenty of rubber for a sustained flight.

--george

 
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Olbill
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« Reply #5 on: September 05, 2017, 05:34:50 PM »

So now there is an added complication of racing to get your model in the air before 3 minutes is up. I guess the smart teams will put a few turns in the motor and launch a "test" flight to get the 5% bonus.
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ceandra
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« Reply #6 on: September 05, 2017, 09:56:50 PM »

My thought exactly, Bill! And, "This is Science"? I guess too much time was being taken for an 8-minute window.

Well, here we go again! Our first build is Sunday, Heli at 1pm, W.S. at 4pm! Marathon day.

Chuck
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Olbill
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« Reply #7 on: September 05, 2017, 10:06:47 PM »

Good luck Chuck!
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Little-Acorn
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« Reply #8 on: September 05, 2017, 10:22:24 PM »

What size rubber motor do you folks use for your planes? And what propeller?

I got a 6" Ikara prop and some 1/16" and 3/32" tan rubber from FAI, seems to make an OK power profile with 1/16" (though I haven't flown it, might be in for a surprise). Runs for about 30 seconds with an old Sleek Streek prop and hanger. Next is the Ikara prop, I'll have to cut it down slightly to suit the 2017-2018 rules.

Am also looking at building my own prop, with very wide blades, made of 1/32" balsa from simplicity. Don't know if I'm wasting huge time and effort for very little improvement.  Only one way to find out, I guess.

Does anyone ever use a single strand of 3/32" or 1/8" rubber, instead of a looped-around double strand? Any reason why a single strand of 1/8" rubber would have any different performance than a loop of 1/16"?
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Olbill
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« Reply #9 on: September 06, 2017, 11:42:14 AM »

Way back in the beginning of Wright Stuff the rubber maximum was specified by length ( I know - stupid rule). I think the specification was a loop measuring 12" max. I was coaching a middle school team and had them work with a single strand motor that was around 18" long. They were doing 3 minute flights with that motor while nationally the best flight times were lower.

Their team made it to Nationals. About a week before the Nationals someone in the national organization got wind of what we were doing and made a rule clarification that ruled against single strand motors. This led to a mad scramble to reconfigure the models for a 12" loop. Performance was still good enough to be in the running for a first place. Unfortunately the "powers that be" had another trick up their sleeves.

My team was winding motors off the plane and used o-rings per standard indoor practice to remove the motors from the stooge and put them on the model. AT THE COMPETITION the o-rings were ruled illegal and the team had to remove the o-rings from their motors. They had never wound motors on the model before and had not handled wound motors without o-rings but were forced to fly their competition flights that way. I think they recovered well enough to place third.

The moral of this story (besides the fact that I'm, still po'd about it) is that anything that seems different to the organizers is like waving a red flag in their faces. A max 1.5 gram single strand motor SHOULD be totally legal and MIGHT give good results but you will have to figure that out with your own testing.
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Olbill
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« Reply #10 on: September 06, 2017, 05:13:40 PM »

This is probably a dumb question but is this the first time that Wright Stuff models can be built with solid flying surfaces (like foam)?
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bjt4888
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« Reply #11 on: September 06, 2017, 06:11:54 PM »

Bill,

I believe that the rules in the recent years allow solid flying surfaces as long as they are not "pre-covered". I have had teams of middle schoolers fly "sleek streaks" at Invitationals I have judged.

Little acorn,

Regarding your question about rubber thickness, there is very good information in the 2017 Wright Stuff topic that would be a good starting point for this year as the prop size is unchanged for 2018.

Chuck,

Best of luck with your building this weekend!

Brian T.
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Jonoton
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« Reply #12 on: September 09, 2017, 10:43:22 PM »

Hello,

For what it is worth,  I just built a Blatter 40 today. I intend to help with Wright Stuff if there is a school in the area that will be doing the event, so this is the beginning of my practice regimen.

I used a sheet of 1/16" from Jo Anne's fabric which I calculate to be an average of 6.3 lb/ft^3. The motor stick is from 8.15 lb/ft^3 wood. Esaki tissue and sig-bond aliphatic glue. The prop assembly is a cut down and balanced 6" Peck prop/plastic bearing/ shaft which weighs in at 3.062g once cut to 5.5" and balanced.

Without the landing gear assembly, it came out to 5.125g rtf without the motor band. I havent flown it yet... but at first blush, it looks like meeting the minimum weight for this year will be rather easy? Of course the Blatter 40 does leave some surface area on the table for this year's rules.

Perhaps intentionally building with larger wood sizes so as to build more durable (hard to type, all I've ever known is 'build to fly, not to crash! ) and consistent models which are less susceptible to environmental changes will be more successful for the average kid.

Best regards,

Jonathan


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ceandra
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« Reply #13 on: September 10, 2017, 01:24:16 AM »

Bill's Finney in the plan library is not far from this year's rules, except prop. Probably a very good starting point. Might need a slightly longer hook to hook for the long rubber needed with the smaller props, and some of that should go up front to make up for lighter prop. Can't go wrong starting with Bill's plans.

Chuck
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Jonoton
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« Reply #14 on: September 13, 2017, 12:19:35 PM »

Chuck: Thank you for that suggestion, I have found the plan.
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ceandra
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« Reply #15 on: September 13, 2017, 12:31:38 PM »

We built one last weekend in a 3-hour session, it went quite well. Two of three kids were new to the team, but listened and performed well. Hardest part was keeping them all busy.

I pre-formed 1/16" 5# balsa on curved containers of the right diameter for ribs, and for tip plates, then they sliced the ribs out with Master Airscrew stripper. Motor stick has 16" hook-to-hook, with longer nose for lighter prop. LE and TE are shaped from 3/32 5# stock, 3/16 wide, tapered to nothing. Otherwise, very similar to the plan.

We are hoping to test fly Tuesday.

Chuck
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