6-10 meter XC ship design Ideas

[ajhockett]

I want to design and build a 6-10 meter high aspect ratio ship. 4-5 wing sections. I have the capabilities to get the positives cut for the molds and to make the molds, and the plane, however I am going to need some help designing the plan form. I wanted to post up here for help designing the plane and or recommendations on where to start in the design process. Time line for me to have these molds built would be ideally before the end of the year.

[DT56]

Quite a project!

I'd start with a good wing design program. I'm partial to CompuFoil from SoarSoft.

http://www.compufoil.com/index.shtml

I'd spend a lot of time in the composites forum, searching for large sailplane projects. I'd also be inclined to build a flying prototype from glassed foam for testing, before going to the trouble and expense of building molds.

What sort of root chord are you considering for your 10 meter wing?

Do you have a particular airfoil or airfoils in mind?

Good Luck!!!! :)

[scaflock]

Another thing to consider is if you want it FAI legal. At that span it's going to have to have a narrow cord to make the limit on area. The longer the wing, the narrower the cord will have to be. I think the Merlyn was designed to be at the max allowed area. You might want to take a look at it for more ideas.

[ajhockett]

I knew of the weight limit but not area.... Thanks for the input guys I will post more as it comes

[PizzaHunter]

ajhockett, do you really think that you need RC glider with such big dimensions? Maybe full-size glider for 1 person would be more interresting?
Something like this: http://aerola.com.ua/index.php?page=planers&id=56&pid=5&type=special

[ajhockett]

i have decided that I am going to enlist the help of a professional consulting company. I will post the design parameters as they come for everyone to give their input. I intend to make this plane a kit and offer it for sale.

[ajhockett]

I have searched for the official FAI rules and regulations but cannot find them, anyone have a link?

[ShredAir]

At the size you'd like your glider to be, the only FAI parameter of interest will be the weight limit of 5kg. It'll be an interesting challenge to build a 6-meter or bigger plane to that flying weight and make it strong enough for the rigors country flying.

Dieter Mahlein, ShredAir

[Miraj]

Scale gliders?

[jgs99v]

Off site landings would be very interesting - funny how rusted pipes are left in the ground that are hidden by tall grass - oppps!

[Petem]

Not sure of the reference, but will have a look.
As well as the 5kg AUW limit there is a total area (includes tailplane) limit of 1.5 sq M, I think. Plus some limits on automatic control of the aircraft?
Early XC machines like the Sagitta XC and Merlyn were built to the maximum area and one limitation was that at max AUW the wing loading was still quite low in XC terms.
The other major factor is chord, which determines the max height you can track the aircraft visually.
If competition or records are not the aim, you can build to any parameters that suit you within your national regulations.
All the best with your project,
Peter

[jbeanelliott]

You may already have read it, but also of interest is the related thread below and especially the post by SoarScale2 (Tony Elliott) in which he provides an attached file (Stall Control.pdf) with a thorough explanation of why he uses a combination of both washout and increasing camber at the tips for the airfoils of his very large scale ships.

"Which airfoil 4meter scale glider with flaps"
http://www.rcgroups.com/forums/show...ut#post11313927

Sorry, link above may be bad try this one below or search for the
title of the thread "Which airfoil 4meter scale glider with flaps"
http://www.rcgroups.com/forums/showthread.php?t=979256&highlight=Which+airfoil+4meter+scale+glider+with+f laps

Excerpt from the .PDF file by Tony Elliott mentioned in the above thread:
"After building wings with aspect ratios of 54:1 and wing spans over 10 meters, I can tell you from personal experience that these methods work and they work well."

[tkallev]

Per current rules: ftp://www.fai.org/sporting_code/sc4/sc4_f3_soaring_09.pdf

5.3.1.3. Characteristics of Radio Controlled Gliders F3B

a) Maximum surface area (St) ............................... 150 dm2

Maximum flying mass ........................................ 5 kg

Loading .................................................. ............ 12 to 75 g/dm2

Minimum radius of fuselage nose ...................... 7.5 mm


FAI/CIAM website: http://www.fai.org/aeromodelling/documents/sc4

tom

[Phoebusflyer]

jbeanelliot, your link did not work. please check and repost?

[Phoebusflyer]

ajhockett, if I were going to the trouble of building that large a plane, I would build one I could ride and fly in. Nothing matches the feel of piloting from the inside anyway! Yes, models are fun and great fun, but when the size moves on up, then consider crossing over to the full scale side!
Pizzahunter, can you post that one in english? I can't read any of it, but it does look interesting!!!

[lincoln]

jbeanelliot, your link did not work. please check and repost?
I got it to work by hitting "try again". Then I went away, and came back, and I still had to hit the "try again". Not sure if that's the same for all browsers. This was Firefox on a PC.

OOPS! I didn't read carefully enough and reported my problem with a link in an adjacent message! Sorry about that. But I'm glad I followed the other link because that's a really nice looking glider. And the scale pilot figure standing next to it is REALLY lifelike. Not to mention the scale bystander just barely visible to the left. ;-p

[jbeanelliott]

Sorry for the bad link above, try this one below.

http://www.rcgroups.com/forums/showthread.php?t=979256&highlight=Which+airfoil+4meter+scale+glider+with+f laps

Or if that still does not work search for the title of the thread
"Which airfoil 4meter scale glider with flaps"

-John Elliott

jbeanelliot, your link did not work. please check and repost?

[ajhockett]

I just assume fly the club gliders than build my own (full scale). At least until I have some more building experience...

[yyz]

aj,

How is this effort coming along? Can you post some photos, sketches, etc?

Mike

[lincoln]

I think in the USA it wouldn't be necessary to comply with the FAI limit. AMA limits are more generous, if I'm not mistaken. Certainly I've seen an RC glider that busted the FAI limits. I think the span was 24 feet. It needed its own trailer. Somehow it was launched with one (or was it more?) of the winches used at the Nats that year, which I could bog down with the strong, low aspect ratio two meter I was flying.