Wright Stuff B

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Re: Wright Stuff B

Post by carneyf1d » May 2nd, 2009, 7:09 pm

there are ways to compensate for changes in humidity, temperature changes,etc . only slight changes need to be made though. if temperature is low, you can most likely decrease the propeller spin rate by using smaller rubber. When the temp increases use a slightly larger rubber size. Just look and see how each temperature, density, pressure, etc affect lift and thrust. I know only two flights is rediculous, but use your trim time wisely, and make very small adjustments later in the day for actual flights.

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Re: Wright Stuff B

Post by andrewwski » May 2nd, 2009, 8:06 pm

gyourkoshaven wrote:I feel really left out, because our plane got 7 and 3 seconds in our run yesterday. Supervisors would remember our plane as the one with the wad of clay on the front. I am making my team's plane for next year, as I am the only one on my team who has an interesting building one, yet hasn't miserably failed(yet). So I have 2 major questions: 1. Should my wings be flat or curved? 2. Should I put those things that stand up straight on the sides of the wings? Any help is appreciated. And yoyosciencekid: I know how you feel, it is really awful to have a building event broken on the bus/at the competition.
1. The wings absolutely need to be curved. Flat wings won't give you any lift.

2. Do you mean the dihedral (wing tips)? If so, they shouldn't stand straight up, they should be anywhere from 10 degrees to 45 degrees depending on your plane design. But you definitely want them. Without raised wing tips, you're going to have a lot of trouble making the plane stable.

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Re: Wright Stuff B

Post by jander14indoor » May 3rd, 2009, 3:59 am

calgoddard wrote:Jeff:

I would be interested in how you recommend dealing with the following problem.
<SNIP>
None of our Event Superisors at our Wright Stuff competitions ever allow any test flights after 8:00 a.m. In addition, it is our understanding that our teams would be subject to possible DQ if they somehow gained access to these gyms and made test flights in the morning on any day before the compeitions. This is definitely the rule at our regionals.
<SNIP>
Hope the other answers helped on temp, not sure I have much guidance to give on that. I always compensate at the time with test flights. As the rules allow.

Here's one thought. Temps in those ranges probably affects the torque output of the motor far more than the lift. Test wind and unwind motors of different thicknesses at different temps graphing the unwind torque vs turns especially. Try to find a motor thickness that matches your good times at 60 F with one at 75 F. Start there the day of the competition.

Now as to the other comment I left, ARGGHH. The rules specifically allow test up to the last half hour of competition. They now also allow test flights during your seven minutes. They do not ban testing in the tournament gym. This is on purpose! The rules writing team (of which I am but one member) considers what it puts in VERY carefully. And is not like this event is new, we've had years to refine them. Why, oh why do event supervisors feel the need to add conditions to carefully considered rules established by the national. And if you have a big gym its easy to set up an area for testing separate from the competition area and keep the flow of the competition itself going. Oh well, the supervisors are still volunteers doing their best. Your only choice is to discuss issues like this with them calmly and rationally and hope for the best, or volunteer and become part of the system.

Glad to hear your students won any way, sounds like they were prepared which is the best thing all us coaches can hope for.

Jeff Anderson
Livonia, MI

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Re: Wright Stuff B

Post by jander14indoor » May 3rd, 2009, 4:06 am

I don't have a detailed report from the MI state contest yesterday, I was running Helicopter Duration as a trial event. But I spoke with the event supervisor and the high time in our usual 23 ft gym was 2:15 or so. And some of that height was risky due to newly installed ceiling fans. Not running, but they were MONSTERS. Probably 15 ft across, 7-8 blades, on either side of the middle, and the lowest things in the site.

Jeff Anderson
Livonia, MI

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Re: Wright Stuff B

Post by Iceman » May 3rd, 2009, 5:02 am

Hi Jeff,

Wrote set of rules for Helicopter event years a go but politics at the time were much different. Went over to watch Ohio State trail event it was surprising seeing those massive copters. Lots of torque problems they were having with blades. There were two teams with effective designs that did well many other interesting creations. The schools were allowed multiple entries about six totals from both schools. They all were bunched close in 50 second area. What about at Michigan and times?


calgoddard,

With some data graph could be made to predict all situations. The concepts to consider would be more appropriate for older high school kids who have taken
Proper advanced math courses it could be done though. The only choice is to get into gyms during year at various tempertures to find torque and rubber size. Concerning humidity I wouldn't worry about it as normally doesn't have much of an effect espacially during S.O. season. What will be void are drafts, crowd heat, air rises etc. specific to State or Regional sites.
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Re: Wright Stuff B

Post by yoyosciencekid23 » May 3rd, 2009, 5:19 am

responding to the question,
the wing definitely needs to be curved to give sufficient lift.
i also reccommend that you do the same to the stabilizer with ribs.
sanding the leading edge on each also proves to provide more lift because the air will coast over and around the wing and stabilizer instead of running into flat balsa.

wing tip plates also are extremely useful for stability
in one of our designs however the wing was curved up with ribs and only tilted at the ends at almost a ten degree angle and that worked extremely well too
(that was jtlamberts backup plane) :) :) :)
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Re: Wright Stuff B

Post by jander14indoor » May 3rd, 2009, 2:05 pm

Iceman wrote:<SNIP>Went over to watch Ohio State trail event it was surprising seeing those massive copters. Lots of torque problems they were having with blades. There were two teams with effective designs that did well many other interesting creations. The schools were allowed multiple entries about six totals from both schools. They all were bunched close in 50 second area. What about at Michigan and times? <SNIP>
Don't want to even get into politics and SO. Don't know that we'll get an effective helicopter event, I can but try. Probably another year before we can make it an official event.

As to results at MI state, a little disappointing from the performance standpoint. Best time was 24 seconds. However, we did have 13 teams from different schools try so that was encouraging. More teams attempted it, but ran out of time between regionals and the state contest. So the interest seems to be there.

I also had time to try out a copter sent me by an experienced indoor flyer. 3.2 gm wt with two counter-rotating tissue covered rotors of 40 cm span. It flew real pretty, 1:30 or so on 1 gm of .100 rubber in a 24 ft gym. Except for the hollow tube motor stick, nothing most students couldn't build. Of course just looking at the wood used, you could see the value of 50 plus years of wood selection experience. Based on that, I'll probably recommend we drop the min weight to 3.5 to 4.0 gm and up the rotor size to 40 cm.

Jeff Anderson
Livonia, MI

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Re: Wright Stuff B

Post by smartkid222 » May 3rd, 2009, 6:56 pm

jander14indoor wrote:
Don't want to even get into politics and SO. Don't know that we'll get an effective helicopter event, I can but try. Probably another year before we can make it an official event.
A helicopter event! NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO. I was looking forward to BLG or WS back in div C in 2011after eggonaut leaves.
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Re: Wright Stuff B

Post by jander14indoor » May 4th, 2009, 3:37 am

smartkid222 wrote:
jander14indoor wrote:
Don't want to even get into politics and SO. Don't know that we'll get an effective helicopter event, I can but try. Probably another year before we can make it an official event.
A helicopter event! NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO. I was looking forward to BLG or WS back in div C in 2011after eggonaut leaves.
Its not that bad. And like I said, not a done deal yet, we're working real hard to make it comparable to WS and BLG for slow elegant flying. If it does get in, I think you'll like it.

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Re: Wright Stuff B

Post by wlsguy » May 4th, 2009, 4:19 am

smartkid222 wrote:
jander14indoor wrote:
Don't want to even get into politics and SO. Don't know that we'll get an effective helicopter event, I can but try. Probably another year before we can make it an official event.
A helicopter event! NOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOOO. I was looking forward to BLG or WS back in div C in 2011after eggonaut leaves.
I think Smartkid222 is worried because there is so little information out there on Helicopters. A quick google search will turn up dozens of sites about indoor free flight but almost no one is flying helicopters competitively.

This could be solved with very detailed info on the wiki or good links from the SO event info site.

On the subject of practice flying during the competition. While the rules state that practice flights are allowed, it leads it off with "at the Event supervisors discretion". In most cases, practice flights are not permitted (I think it was permitted at 1 of the 6 competitions this year). Maybe one more line could be added to help clarify the intent of the rule writers. Something like, "Event Supervisor should attempt to accomodate practice flights whenever possible"

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