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Author Topic: SO Wright Stuff 2020  (Read 4598 times)
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cxflyer
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« Reply #100 on: November 24, 2019, 03:48:01 PM »

Has anybody's team broken 1 min 30 sec on a Wright Stuff 2020-conforming flight? Just one flight, either circling left or right, not two flights together.

Inquiring minds want to know!    Smiley


There was a flyer on scioly.org that broke 1:50 to both the left and above 1:45 to the right.
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bjt4888
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« Reply #101 on: November 24, 2019, 04:56:14 PM »

What was the ceiling height?
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Maxout
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« Reply #102 on: January 10, 2020, 06:57:19 PM »

Here's the first installment in my 2020 Wright Stuff Review series, and the first thing I review is the rules set and what happened after it was released! Spoiler: it's not pretty.
https://youtu.be/cVXurA8nDrA
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flydean1
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« Reply #103 on: January 10, 2020, 08:47:09 PM »

I was thinking about getting involved with SO along with my EAA chapter.  Not interested.  Makes dealing with the FAA a simple process.
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Crtomir
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« Reply #104 on: January 12, 2020, 09:38:50 AM »

Here's the first installment in my 2020 Wright Stuff Review series, and the first thing I review is the rules set and what happened after it was released! Spoiler: it's not pretty.
https://youtu.be/cVXurA8nDrA

Wow!  That's intense.  This year's rules are making for a truly miserable experience.  Although, if our students do eventually get their planes to fly, they will feel a big sense of accomplishment.

Your explanation of the very narrow airstream from the small propeller interacting with the very small stabilizer seems to jive with exactly what our students have been seeing with their planes.   They can't get their planes to fly at all. They either climb up fast, stall, and then fall backwards to hit the ground, dive into the ground from the start, or start to climb but then start diving over into the ground.  No matter what they do, they cannot get their planes to fly very well.  The have tried moving the wing up or back on the motorstick, adjusting the wing incidence, adjusting the stab incidence, changing rubber thickness, changing propeller designs, and adding ballast to the nose.  There seems to be only a tiny margin where they can barely get their planes to fly.  And these are students that have been doing Wright Stuff for 3 years previously and so have a lot of experience.  They are getting so frustrated. 

So my question is, could it be that that highly nonlinear and sensitive effect of the propeller downwash airstream interacting with the small stabilizer is the cause of all this?  I noticed that our students are mostly using stabilizers with some camber, but a lot of the kits (from what I can see online) have flat stabilizers.  Also, the few planes I have seen in our group that have flown with any level of decency have used flat stabilizers.  Does having a flat stabilizer minimize the prop downwash-stab interaction effect you mention in your video?

And if that is the case, why not place your stab and rudder high up above the prop downwash?  Maybe we will try this. 
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Indoorflyer
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« Reply #105 on: January 12, 2020, 10:30:07 AM »

Something I've wondered about, but never personally tested, is a performance comparison of bottom-covered stabs (flat) vs conventional top side covered ones.   Dick Baxter's 'Pussycat' design has a stab with covering on the bottom (only).  It also has twin fins...
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bjt4888
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« Reply #106 on: January 12, 2020, 10:48:40 PM »

Ctr,

Our airplanes are flying well, but this year’s rules definitely make trimming sensitive. We are flying about 35% static stability margin with about 4.5 degrees of decalage angle. So, quite safe in pitch stability. A shift rearward of even 1/8” in the CG, along with less decalage resulted in poor recovery from ceiling hits or bad air. A small shift forward in CG of 1/8” resulted in continuous slight nose-down flying during let down. This trim is a bit “draggy” but we are getting repeatable good flights.

I have posted (and Coach Chuck has pasted) a number of specific suggestions on the Scioly.org forum, based upon my team’s experiences this year, that some on the forum have found helpful.

We have tried several propeller styles (symmetrical, semisymetrical, flaring, etc.) and a number of pitch angles on each style) and are starting to get things sorted out. Managing climb rate with the small propeller is one of the key issues this year.

Brian T
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bjt4888
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« Reply #107 on: January 12, 2020, 10:50:05 PM »

...Coach Chuck “posted”, not “pasted”... typing too fast.
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Maxout
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« Reply #108 on: January 13, 2020, 02:18:47 PM »

I was thinking about getting involved with SO along with my EAA chapter.  Not interested.  Makes dealing with the FAA a simple process.

Coaching students is much easier than the stuff I'm dealing with. If you can find middle school students to get involved with, do so. The rules for ELG this year are a treat and result in very nice flying planes. Wright Stuff is a pain in the neck this year, but look at last year--the rules were a dream last year with planes that flew super easily. Get with a school that is serious about this and they'll do anything you want in return for your coaching. Not kidding--I get paid for a lot of the coaching work I do.

Wow!  That's intense.  This year's rules are making for a truly miserable experience.  Although, if our students do eventually get their planes to fly, they will feel a big sense of accomplishment. 

Yup. It's messed up. That said, it is possible to get the planes flying, at least so long as the air isn't blowing. If they had allowed bigger stabs and/or props, the rules this year would make for trivial trimming efforts though, and the top flight times would be only a little longer.

Your explanation of the very narrow airstream from the small propeller interacting with the very small stabilizer seems to jive with exactly what our students have been seeing with their planes.   They can't get their planes to fly at all. They either climb up fast, stall, and then fall backwards to hit the ground, dive into the ground from the start, or start to climb but then start diving over into the ground.  No matter what they do, they cannot get their planes to fly very well.  The have tried moving the wing up or back on the motorstick, adjusting the wing incidence, adjusting the stab incidence, changing rubber thickness, changing propeller designs, and adding ballast to the nose.  There seems to be only a tiny margin where they can barely get their planes to fly.  And these are students that have been doing Wright Stuff for 3 years previously and so have a lot of experience.  They are getting so frustrated.  

Sounds like you need to move the CG forward. What I've taken to doing is to put all the ballast on the nose of the plane, and then slide the wing forward until it balances at 45% chord for biplanes, 55% for monoplanes. Add incidence until you get a good nose-high cruise going--don't even try for a climb initially, and start by trimming for left circles. Once the plane is flying in a stable manner, add more turns to look for a climb. Start adding downthrust if you see any stalling at higher power settings. If as you add left rudder to get that left turn going, the model starts to crank in, add a small amount of washin to the left wing and you should see a nice, stable climb. After that, try for a right turn. You'll *usually* need more right rudder than you did left, and the pitch trim may change, requiring additional stab incidence which must be documented so you can get repeatable results.

If all else fails, buy the Lasercutplanes.com kit which literally flies right off the board after you add a little incidence under the wing (I also needed to shim the stab for some extra incidence when flying to the right). It's a weird plane but it flies well.

-Josh
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Crtomir
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« Reply #109 on: January 20, 2020, 09:55:25 AM »


Sounds like you need to move the CG forward. What I've taken to doing is to put all the ballast on the nose of the plane, and then slide the wing forward until it balances at 45% chord for biplanes, 55% for monoplanes. Add incidence until you get a good nose-high cruise going--don't even try for a climb initially, and start by trimming for left circles. Once the plane is flying in a stable manner, add more turns to look for a climb. Start adding downthrust if you see any stalling at higher power settings. If as you add left rudder to get that left turn going, the model starts to crank in, add a small amount of washin to the left wing and you should see a nice, stable climb. After that, try for a right turn. You'll *usually* need more right rudder than you did left, and the pitch trim may change, requiring additional stab incidence which must be documented so you can get repeatable results.

If all else fails, buy the Lasercutplanes.com kit which literally flies right off the board after you add a little incidence under the wing (I also needed to shim the stab for some extra incidence when flying to the right). It's a weird plane but it flies well.

-Josh

Thanks Josh.  I ordered three of the Laser Cut Planes kits and a couple of the students built them in about 1.5 hours.  They really enjoyed the build, especially the unique prop design.  And you were pretty much correct when said it flies right off the board. They didn't have any of the problems that I described with their earlier planes.  They don't have them flying perfectly yet (some climbing issues to work on), but I can tell you that their flying experience was a lot more enjoyable than it has been all year.  Now, thye can concentrate on the "normal" trimming process and rubber band (thickness/length) selection.  Their spirits were high and they were so much more enthusiastic about flying again.  Thanks for suggesting that.

I think what we are finding is that the plane needs to be light enough so that a lot of weight (built-in or added ballast) can be put at the nose to move the CG very far forward.  Otherwise, you run into serious stability issues.  That's my feeling and seems to go along with your advice. 

Last year, we ordered some of your Wright Stuff kits and the students enjoyed the simple, but very effective design.  It's nice to see that there several expert flyers providing good quality kits for Science Olympiad flying events.  The kids often use them as a good starting point and then often start doing modifications throughout the season.
 
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Little-Acorn
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« Reply #110 on: January 25, 2020, 04:24:45 PM »

This year's rules say we can have either a monoplane or "biplane configuration". Pretty obviously that means two wings, one above the other.

Is there anything in the rules prohibiting us from having two stabilizers, one above the other?

As I recall, if there isn't specific language in the rules prohibiting something, judges will usually allow it.

Right? Wrong?
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ceandra
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« Reply #111 on: January 27, 2020, 12:40:34 AM »

I would get it addressed in an faq. Otherwise, even if so says it's ok, an ES may tier it. Print the faq when it is answered, and keep it in your notebook

Chuck
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cxflyer
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« Reply #112 on: January 27, 2020, 02:06:29 PM »

Two stabs seems very risky; don't think that'd be allowed, but never hurts to ask.
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Olbill
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« Reply #113 on: January 27, 2020, 03:48:00 PM »

Rule 5.d. is written so badly I'm amazed that most people are coming up with the same meaning for it. See photo. The first sentence leads you to believe that it is okay to NOT use the same airplane but there's nothing to tell you what to do next if you make this choice. Is it really too much trouble for someone to read this crap before they publish it?

As far as two stabs go, the only hint that biplanes might be okay is the term "wing(s)" in the rules. The stab description says "stab" singular. My tentative impression is that either a bi-stab isn't allowed or (what seems more likely) the rules butcherers didn't think of it as a possibility. I would advise against it unless there is a specific rule clarification that says it's okay.
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ceandra
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« Reply #114 on: January 27, 2020, 03:56:11 PM »

Bill:

Rule 1, at the top of the page, states:

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

Therefore, biplanes are explicitly allowed, whereas a triplane would not be allowed. Were it simply for the plurality of the word "wings", I would be trying a triplane...

Chuck
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Olbill
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« Reply #115 on: January 29, 2020, 09:52:34 AM »

The prop has raised some unexpected issues. For my experimental model I used a 1/16" sq. bass spar. Every time the model hit something it sheared off one or more blades. And trying to stop the prop after that happens is not advisable.  I'm thinking a cast plastic prop would be nice if such a thing existed.
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klastyioer
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« Reply #116 on: January 29, 2020, 09:58:42 AM »

The prop has raised some unexpected issues. For my experimental model I used a 1/16" sq. bass spar. Every time the model hit something it sheared off one or more blades. And trying to stop the prop after that happens is not advisable.  I'm thinking a cast plastic prop would be nice if such a thing existed.
a faq was submitted, if you're able to catch the plane right before it hits the ground, it should prevent the shearing
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Olbill
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« Reply #117 on: January 29, 2020, 01:48:21 PM »

The prop has raised some unexpected issues. For my experimental model I used a 1/16" sq. bass spar. Every time the model hit something it sheared off one or more blades. And trying to stop the prop after that happens is not advisable.  I'm thinking a cast plastic prop would be nice if such a thing existed.
a faq was submitted, if you're able to catch the plane right before it hits the ground, it should prevent the shearing


A wire skid will help prevent damage from landing. Wall hits are a different matter.
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bjt4888
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« Reply #118 on: January 30, 2020, 10:49:10 PM »

Yes, even with judicious use of carbon, glass cloth reinforcement and mostly plastic blades, we’re repairing propellers regularly this year. This is making us lean towards flying conservatively as a propeller broken and unrepairable in the 11 minute window essentially cuts your score in half (no clockwise/counter clockwise bonus).

We’re mostly flying well though (1st, 2nd and 3rd at our first Invitational). Some ceiling hit crashes when testing new trim and propeller combinations.

Brian T
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ceandra
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« Reply #119 on: January 31, 2020, 12:55:10 AM »

Bill:

We use a wire skid, but of course we need to chase the plane down quickly to measure remaining turns for our log.

Thin carbon or wood spars seem out of the question (we were using a single 0.020 spar to get enough flare). They are too fragile, and as Brian notes, if you have to change props, you lose the key bonus. All components except rubber must be used on both flights.

Our basic plane is building at about 6g, which leaves 2g to ballast, usually up front. Therefore, you can afford to put some mass in the prop. We are using metal spars, and tissue reinforced balsa blades for now, but continually experiment with options. We have seen on some (most) of our flaring props that we get reverse flare. We believe that the high rotational speed is causing centrifugal acceleration to overcome aero flaring. SO has always come down to prop/rubber, and this year is no different, though getting the basic plane to fly is a bit more work. At first look, there is not much to do with these tiny props. However, my kids are trying out some innovative approaches that have shown some promise.

We have Regionals this weekend, and we still have a lot to learn on props. So we are going with fairly basic for now.

Chuck
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Olbill
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« Reply #120 on: February 13, 2020, 03:52:24 PM »

If you're thinking of quadcopter props here are some 3" ones that didn't work. The closest one was the 6 blade but it was turning 3200 rpm. The little fan blade (closer to 2" than 3") was over 6000 rpm. The clear 4 blade prop was over 4000 rpm. I never tested the 5 blade b/c I didn't think there was any chance of it working.
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Wind-it-up
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« Reply #121 on: February 17, 2020, 07:17:25 PM »

Hi Guys - I've been working with Ikara for months and they have finally produced a prop assembly for the 2020 Sci Oly rules!  It's very nicely done with thicker-than-your-normal-Ikara blades to survive wall hits, and they are pitched steeply to keep the RPMs down despite their tiny size. 

We just received them and hopefully it's not too late to try one on your designs! 

https://www.wind-it-up.com/collections/props-for-rubber-powered-models/products/ikara-8cm-prop-assembly

---Chuck Imbergamo
Wind-it-up Enterprises (owners of Peck-Polymers and Golden Age Reproductions)
www.Wind-It-Up.com
https://www.facebook.com/PeckPolymers
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ILM Tarheel
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« Reply #122 on: March 09, 2020, 12:05:08 AM »

The following statistics will perhaps show the true state of the Wright Stuff event in the real world. I attended a large Science Olympiad regional competition this weekend with a total of 27 high school teams participating. I watched and timed every flight from the spectator seating area. Five teams (nearly 20%) did not enter the Wright Stuff event. No team scored the two-flight bonus because only one flight made a complete circle. The longest single flight was 36.7 seconds. Only six flights exceeded 10 seconds. The average time of all flights was 5.3 seconds. Most flights stalled immediately after launch. Most teams had built very well designed models from two of the major SO WS kit suppliers but had no idea how to fly them.

Wright Stuff has always been difficult for students and teams that do not have knowledgeable help and coaching.  Unfortunately, most teams have no help at all. The very difficult to fly planes produced by the 2020 rules made it virtually impossible this year. I saw a number of Wright Stuff models in the trash cans as I was leaving the event.
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cglynn
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« Reply #123 on: March 10, 2020, 10:42:29 AM »

Wow.  5.3 second avg flights.  It is unfortunate that for many students, the WS event will be their introduction to model flying.  I am sure some will realize that it can be better, but I am also sure there are many who right off model flying for the foreseeable future because of their WS experiences.

On the other hand, and this may be overly optimistic, but perhaps teams and their advisers will realize just how important coaching is to be successful in WS.  This has always been true, as the teams that have had mentoring/coaching/access to a regular test flying site have historically performed better than teams that did not.

Should these teams seek out coaching from experienced flyers, perhaps their experiences will be better, and they will also be introduced to other events. 

The team I have been "working" with (I use that term loosely as I really just allow them to use a facility to which I have access and offer advice when it is requested) have done very well with their WS model, averaging 1:25+ both directions.  Though to get there, they have worked very hard, and very diligently.  They have also expressed interest in other indoor events, and even brought a Limited Penny Plane with them during our last flying session.  They have also seen F1L's, F1D's, NoCal, P18, and F1N's flown, so they have an idea of what indoor model flying is and what it can be.

So short story long, find a mentor/coach.  Build an accurate model, and take careful records as you fly it.  If you talk to any of the highly successful indoor flyers, they will all tell you that experience is the key.  Each of them has countless test flights on their models before records were set and contests were won.  Experience is key.
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ILM Tarheel
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« Reply #124 on: March 10, 2020, 01:13:52 PM »

cglynn - I agree that finding a knowledgeable mentor or coach is the key to the Elastic Launch Glider and Wright Stuff events in Science Olympiad. I have been a volunteer “flying” coach to two middle school (Div B) and two high school (Div C) teams for over 8 years. My teams have been very successful both at the region and state levels. With over 60 years of rubber Free Flight experience I have a lot of building craft and flight skills to pass on to the students and fully enjoy doing so. But nearing 80 years old, I am maxed out on time and energy to take on more. I only have, perhaps, one more year in me. 
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