Kaitak744 From United States of America, joined Jul 2005, 2443 posts, RR: 3 Posted (8 years 7 months 2 weeks 5 days 7 hours ago) and read 2995 times:
For a science project, I am in an event where I am supposed to make a plane with a wing span of 50cm, maximum wing chord of 7cm, maximum stabilizer span of 30cm, and maximum stabilizer chord of 4.5cm. It will be powered by a single propeller which is turned by a rubber band (which is winded before flight). The objective is to have it fly for the longest possible time (before any part of the plane touches the ground). Now, does anyone have any design recommendations?
So far, I was thinking of 787 style wings with raked wingtips, but I don't know if that will be so good for a plane going this slow.
Doug_Or From United States of America, joined Mar 2000, 3473 posts, RR: 3
Reply 1, posted (8 years 7 months 2 weeks 5 days 3 hours ago) and read 2956 times:
simplfy. On a plane of that size going for endurance, you'll probably want simple wings. Either rectangular or tapered (as on a Cessna). Sweep will do nothing for you in the speed range you're going for.
Starlionblue From Greenland, joined Feb 2004, 17295 posts, RR: 67
Reply 5, posted (8 years 7 months 2 weeks 4 days 2 hours ago) and read 2838 times:
I will agree with previous posters. A straight, simple wing can be made light and efficient. If you look at real world endurance designs like Proteus, Voyager and Virgin Global Challenger they all have long straight wings.
Kaitak744 From United States of America, joined Jul 2005, 2443 posts, RR: 3
Reply 6, posted (8 years 7 months 2 weeks 4 days ago) and read 2829 times:
Oh, I forgot to mention a few things, sorry. The plane can't be a pre-built kit. I need to make it from scratch. This does however give me alot of design flexibility. Also, I have a prop which is about 18cm in diameter and 1.5 cm in chord. Sounds good enough for a plan this size right?
By the way, Doug_OR, Lowrider, FLY2HMO, and Starlionblue, thank you very much for your help so far.
The idea here is for you to experiment and learn about various airfoils. Asking others for any help diminishes the benefit of your own trial and error. You said this is for a science project; inot a competition, so why don't you learn what you can while you're at it?
Dw747400 From United States of America, joined Aug 2001, 1267 posts, RR: 1
Reply 11, posted (8 years 7 months 2 weeks 3 days 11 hours ago) and read 2748 times:
I judge a similiar competion for the AIAA in Baltimore every year (electric power however, and larger--up to 95cm span), and there are two design concepts that always come out ahead. The first (and best) is a large blasa wing structure covered by thin clear membrane, and most people following this concept seem to use a twin boom tail configuration connecting to a single horizontal tail (because in this competion the planes are theatherd, you can get away without a vertical tail if you balance the aircraft well.) The wing is generally a thick cross section and massive area, most probably exceeding the dimensions you need to stay within.
The second, slightly less effective design might be more practical for you. It uses a straight, foam wing. Generally it is a higher aspect ratio than the balsa designs, and seems to work well.
Meister808 From United States of America, joined Jan 2000, 973 posts, RR: 1
Reply 12, posted (8 years 7 months 2 weeks 3 days 9 hours ago) and read 2736 times:
All I can suggest is to make everything as adjustable as possible. Mount each wing and each stabilizer so that the angle of incidence with the fuselage can be adjusted as much as possible. When making airfoils, they aren't going to be perfect, so making things adjustable allows for you to decrease the lift being made by your slightly more efficient right wing so that there isn't a constant left roll.
Aside from that, I'd just say experiment a lot, make a lot of different stuff and try it all out. I once had to design a plane with max wingspan of 11" to fly in a 24 mph wind-tunnel. I think we worked on that thing for a total of about 300 hours, and we eventually had about 10 fuselage designs and about 20 sets of wings, all interchangable, to work with. We kept trying stuff to see how it would work, and we eventually honed it down to a combination of 3 sets of wings on one fuselage that worked out well.
Twin Cessna 812 Victor, Minneapolis Center, we observe your operation in the immediate vicinity of extreme precipitation
Lowrider From United States of America, joined Jun 2004, 3220 posts, RR: 10
Reply 13, posted (8 years 7 months 2 weeks 3 days ago) and read 2685 times:
Here are some folks that do something that sounds similar to your project. The goal is to make the model fly as long as possible, in confined space. They do some amazing things with lightweight materials. They are fragile and will only work indoors. Maybe it will help.