2016 rules

[calgoddard]

Simple suggested rules for 2016 WS:

Fully assembled free flight rubber powered airplane (made of materials as specified last year) must fit in a box measuring 50 cm x 50 cm x 10 cm in its ready-to-fly configuration. Minimum weight of airplane (without rubber) is 7 grams. No props with mechanisms for actively varying their pitch. No other limits.

The event supervisor and/or his/her assistants have the student put the airplane into a cardboard "measuring box" to prove it meets the size limitation. The box containg the airplane can be put on a scale to weigh the airplane (subtract known weight of box). A simple quick visual inspection will confirm the airplane is made of permissible materials.

My guess is that the size and weight limits as proposed above would keep most flights under 3 minutes in a typical HS gym.

With these simple WS rules:

There is no need to measure rubber motors for weight. Let the students determine the optimum rubber motor weight from research or experimentation. You do not get longer flights by adding more rubber past a given point.

There is no need to measure prop diameter. Let the students experiment with different size props. An excessively large prop will hinder performance and may make it difficult to build an airplane that weighs slightly above the 7 gram weight minimum.

There is no need to measure wing and stab span and chord (and risk damaging the airplane).

Students can experiment with span and chord and can even try biplanes. Again you do not increase flight times by increasing wing and/or stab area past a given point.

Why make things needlessly complicated at check in? Why risk damaging airplanes with span, chord, prop diameter and weight measuements? Why hamstring the airframe configuration so much that the Wright Stuff competition ends up being a contest to see which team of students can do the best job trimming the latest cookie cutter commercial SciOly kit airplane?

Thanks for reading these suggested 2016 WS rules. Your comments would be appreciated.

[retired1]

Interesting!
It probably would separate the teams.

[Less_Incidence]

I am very much in favor of the box measurement system. I don't think a square box is appropriate, as it will result in weird, stubby-looking planes, and 10cm is a little bit too short height-wise and would make biplanes or drop-tailboom designs very difficult, so I'd go for something closer to 50 x 75 x 20cm. Still, I'm very much in favor of the box system. It's very similar to what's been used for B div. trebuchet events in the past if I recall correctly.

[retired1]

I think that Cal's 50 x 50 is reasonable.It puts a premium on who can develop the best plane with those limits. Same with the 10 cm height. We do not need a bigger airplane to use lots of rubber. The drop tail is not an absolute necessity and neither is a biplane. If you can design a highly modified plane with superb performance You have truly achieved a lot. Making it easier should not be the goal of the rules.

[Less_Incidence]

I see your point. I addressed biplanes because Cal mentioned them, but it would still make perfect sense. Given those rules, I might even run off and try to design a 10cm-high biplane... Probably have to put one wing under the motorstick and the other above, and that would make putting the rubber on a royal pain for one person. Now that I think about it, the odd box size does bring a lot of interesting challenges.

[retired1]

A biplane is still a possibility, the wings would be 3+ inches apart vs a more conventional 4".
The tail droop could be about 2" with the wing 2" on top of the motor stick.
Some interesting things might happen if the tail were on the bottom and the plane put in the box on a vertical angle.

I would lean towards a tandem or possibly a take off of the delta dart to have max wing surface.

A pusher / canard becomes a possibility also.

I did not like Cal's proposal when I first read it, but it surely opens up the designs so they will not be cookie cutter ones like this year.

Surely wish that I could be a fly on the wall at the summer institute.

[Less_Incidence]

I think that a canard bonus would be in order for those rules, and a greater bonus for a pusher canard. My hair-brained idea to totally max out the lifting area would essentially be a three-winged plane - a biplane-type wing in the front with tip plates used to connect the top and bottom wings (So dihedral isn't needed), and another wing of the same dimensions in the rear. The ultra-short tail moment of a 50x50cm plane would make a very large stab like that feasible, although the stab airfoil cross section would probably have to be under 2%.

[calgoddard]

Nothing in my proposed rule mandates a "stubby-looking" airplane. If a student thinks an airplane with an overall length greater than its wingspan flies more efficiently he or she can design and build a model with that configuration. The student just has to make sure it fits in the 50 cm x 50 cm x 10 cm measuring box, diagonally or otherwise.

The optimum distance between the wings of an indoor duration rubber powered biplane depends on a number of factors including span and chord. The extra difficulty in building a bi-plane to minimum weight may or may not be worth it. Ditto for the extra challenges of trimming an indoor duration biplane. It would not be hard to design and build a biplane with both wings conventionally mounted on wing posts above the motor stick that would fit within my proposed measuring box.

There is no consensus on whether a drooped tail boom provides any benefit in terms of flight duration.

It would be a good idea to cut out a winow in the bottom of the measuring box suitably positioned for reading the diplay of the digital scale on which the box is placed. The event supervisor or his/her assistant can carefully slide a ruler over the top edges of the measuring box to determine if the airplane in the box exceeds the 10 cm maximum height in a close situation.

[Less_Incidence]

My gut feeling is that maximizing the wingspan would provide the best efficiency over having a long tail moment, but aerodynamics are strange and it's really just up to experimentation. That's the nice thing about your rules, there's a lot of experimentation to be done to find the "optimum" configuration.

As far as the drooped boom, there may not be a consensus, but Bill Gowen only has a whole laundry list of AMA records to prove its worth. I agree it really isn't necessary though, and there's no point in changing the box size just so that one obscure design feature is allowed.

[calgoddard]

Kang Lee is the current world champion in F1D. He also holds the current world record in EZB . None of his airplanes has a drooped tail boom. It is not necessary to have that feature to win any WS competition, including nationals.

Hopefully those in charge will write the 2016 WS rules to encourage and reward experimentation in airplane design. It's discouraging to see virtually every team fly the same airplane at each WS competition year after year.