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The rules for the 2019 season haven't been released yet of course, probably will be on Sept. 5 I believe.

I've been looking at the rules for 2016 Div. B ELG, the numbers for 2019 will probably differ somewhat. Hopefully the basic ideas will be the same or close.

In 2016, Rule 3.c says, "The mass of the glider throughout the flight must be more than 3.5g and less than 10.0g."

I can't find any rule (it's 1:30AM, maybe I missed it) that says the glider's weight can't change during the flight. If the glider weighs 9.5g at launch and drops a 5.5g ballast once it reaches its max height so it glides for the rest of the flight at 4.0g, Does that violate any rules?

If that's a no-no, then how about if the glider has a way to shift its ballast rearward at the highest height instead? This way the glider will drop nothing and will weigh exactly the same throughout the flight. Might be nice to have it extremely noseheavy during launch, but more evenly balanced for a good glide later. Legal/illegal?

No, I haven't the faintest idea how I will get it to drop ballast or shift it. Might be impossible. But food for thought.

Thanx all!

Little-Acorn wrote:The rules for the 2019 season haven't been released yet of course, probably will be on Sept. 5 I believe.

I've been looking at the rules for 2016 Div. B ELG, the numbers for 2019 will probably differ somewhat. Hopefully the basic ideas will be the same or close.

In 2016, Rule 3.c says, "The mass of the glider throughout the flight must be more than 3.5g and less than 10.0g."

I can't find any rule (it's 1:30AM, maybe I missed it) that says the glider's weight can't change during the flight. If the glider weighs 9.5g at launch and drops a 5.5g ballast once it reaches its max height so it glides for the rest of the flight at 4.0g, Does that violate any rules?

The rule that says the flight "stops when any part of the airplane touches the floor" means you can't drop off any pieces during the flight. I took this from last year's Wright Stuff, but there's a similar rule for all the flying events.

meierfra wrote:

Little-Acorn wrote:The rules for the 2019 season haven't been released yet of course, probably will be on Sept. 5 I believe.

I've been looking at the rules for 2016 Div. B ELG, the numbers for 2019 will probably differ somewhat. Hopefully the basic ideas will be the same or close.

In 2016, Rule 3.c says, "The mass of the glider throughout the flight must be more than 3.5g and less than 10.0g."

I can't find any rule (it's 1:30AM, maybe I missed it) that says the glider's weight can't change during the flight. If the glider weighs 9.5g at launch and drops a 5.5g ballast once it reaches its max height so it glides for the rest of the flight at 4.0g, Does that violate any rules?

The rule that says the flight "stops when any part of the airplane touches the floor" means you can't drop off any pieces during the flight. I took this from last year's Wright Stuff, but there's a similar rule for all the flying events.

Ultimately, it's perfectly legal, it just won't benefit you, since I'd expect the flight time to stop when the ballast hits the ground.

meierfra wrote:The rule that says the flight "stops when any part of the airplane touches the floor" means you can't drop off any pieces during the flight. I took this from last year's Wright Stuff, but there's a similar rule for all the flying events.

Yeah, I'd forgotten that. Oops.

Well, maybe there's a way to shift ballast....

Little-Acorn wrote:

meierfra wrote:The rule that says the flight "stops when any part of the airplane touches the floor" means you can't drop off any pieces during the flight. I took this from last year's Wright Stuff, but there's a similar rule for all the flying events.

Yeah, I'd forgotten that. Oops.

Well, maybe there's a way to shift ballast....

Assuming you build near the minimum weight, what are you trying to achieve by shifting the ballast?

I'm considering shifting weight, so the glider can be very noseheavy during launch, but balances closer to the ideal glide point once it slows down and transitions to the glide.

Whether that's possible, I have no idea.

Some people have been building gliders with "flaps" - wide wing trailing edges which, I gather, sit perfectly flat with the rest of the wing during the high speed of the launch, but when the glider slows down at the top of its flight, the flaps droop slightly due to reduced wind velocity, which increases effective wing incidence and gives a greater effective angle between wing and stabilizer.

Same basic idea. I might ultimately go with the flaps idea since (a) it's simple, and (b) there are many examples to study.

Unless you are flying in an extremely high ceiling site, Gliders of the 3.5g weight had no trouble reaching the ceiling in every gym we competed in so I don’t see the advantage to being too much higher than the minimum.

The kit gliders my not for profit company is offering this year typically build to around 4.5g ballasted. They could be lightened but quickly become fragile in the hands of beginner fliers and students become frustrated so we made them a little more durable (adding weight).

My advice, become an expert using the conventional methods and then try the innovative approaches.