silver_moon_beam

I'm attempting to build a glider that will take the longest possible time to reach the ground, but I have no idea what to do.

There are specific parameters it must be within:
Wingspan- Max 40 cm
Wing Chord- Max 10 cm
Horizontal stabilizer- Max 28 cm
Weight- From 2-10 grams
Materials- wood foam paper, plastic film covering and glue.


It can have multiple wings (biplane) as long as each individual wing fits the size criteria.

Can anyone help me design this thing? I also need to be able to have it together by the end of March.

Anything would be helpful, thanks.

evan-RCU

So you have a design project and you want us to design it for you? School or work?

silver_moon_beam

School competition, I'm just wondering if there are any definite things I should watch for.

evan-RCU

We're not going to help you much, it's your project. My only rcommendation is to get the lightest loading you can. Build it the biggest you are allowed and make it the lightest you are allowed.

SoCal GliderGuider

Look in the freeflight section of this web site and on rc groups.

simhatus

Hi

I think you should use an aerofoil similar to the diagram, use the full 40cm wing span but not a biplane. make sure it balances at the 3cm mark. will need some dihedral for stability.

Is the wingspan measured as the span or length of the wings? in the first case the more dihedral you have the longer the wings can be. to much dihedral and they would start to become ineficient, i wonder what the optimum angle would be for a given span?

BMatthews

If you're looking for maximum duration from a given launch height then you cannot make it too light. In a purely physics outlook your model will have a given amount of potential energy by raising it above the landing point. The lighter it is the less energy will be needed to hold it up and the longer it'll take for the total energy to be "consumed".

Search on the varous model sites and generally on the internet for "indoor model airplanes". You'll soon see that you can make a model that looks like a spiderweb covered wtih a soap bubble film and it'll be very light. That's your path to the best duration... provided you don't need to actually throw it to a height higher than what you can reach.

You won't manage it the first time around but it's quite possible to build a model that matches your size restrictions and have it weigh under a gram using indoor materials and methods. If you take the time to build successive models there's no reason why your second or third one can't be down to between 2 to 3 grams.

And then find an NBA player to hold it up and launch it...