jeffie8696

OK here is one for the engineers out here. The Stick has an airfoil with an open bottom. Would there be more lift if it had a flat bottom? I would think this could be done with some mylar and kept fairly stiff. [8D]





The way I fly I would still have to then fill it with helium to avoid a crash.[:@]

jdetray

I'm no engineer, but ...

The term for this sort of "open bottom" airfoil is "undercambered." If you put a flat bottom on it, the wing will have less lift and also less drag than the undercambered version. So the plane will want to fly faster and in fact will need to fly faster because it will have less lift.

Undercambered wings are great for slow flyers precisely because they develop lots of lift at slow speeds.

I'm sure someone has flown a Slow Stick with a flat bottom wing and can tell us how it performs.

- Jeff

calvino

ive done it with a flat wing, it works good, i didn't notice much loss of lift BUT it helps a TON in the winds due to the fact that it has to fly faster, normally when i would have to bring it in, i could stay up, helps alot, ads like maybe 5 mph or so to the top speed, noththing to bad

jeffie8696

I was hoping the flat bottom would give the air more to push against and keep it aloft better. I do fight a lot of wind issues here, it is seldom ever calm. I think I just remember seeing a breif test of a wing design that was similar to the Stick and I believe they came to the conclusion it had poor stall . But I may be wrong.

blk822

The airfoil design of the slo stick is a very old design and gives ALOT of lift at a slow speed. People have done many things to the wing on the SS. Like taking two wings and clam shelling them to have a symetrical wing for inverted flight and such, also the flat bottom wing, and if you cut the ends off the wing it will go faster and handle wind better. Bets thing to do on a SS first is a Brushless motor and lipo battery set up then worry about the wing. Also move the landing gear right up to behind the motor mount, keeps it from nosing over on take off and landings.

jeffie8696

Thanks for reminding me about the landing gear, I am in the middle of a rebuild (seems like I do that a lot) and it will be easy to change it right now. I already run a brushless and lipo and yes it made a huge difference. I tried to make the stock power system work with an old 9.6V nicad from a Tyco truck, and it flew like a truck!!! [sm=lol.gif] But I learned a lot about flying within the limitations of the airframe.

blk822

I used the stock landing gear pushed forward and then soldered in a cross bar so the gear wouldn't squat . It still will bend back on hard landings but not as much and won't spread. I was flying my SS with a 2217 supo motor 20amp esc apc 8x6E prop and a KongPower 11.1v 2200mah 25c battery. A real power house of a SS, but dives very fast. Could fly for like 15 minutes and still not run the batteries all the way down. The extra weight helped in the wind also. Was putting out 200 watts, the esc would get warm and the motor would get hot if ran at WOT to long. Was a screamer. I have sence pulled the motor and esc for a E-flite Ultimate FX 3D plane.

jeffie8696

I am just running a Tower 2408 and a 20 amp esc with a 2cell-750 lipo. I have no issues with the power. Directional stability yes power no. [sm=lol.gif]




Maybe I need to install a parachute? auto deploys at low altitude if the approach angle is too steep? (usually straight down. )

jeffie8696

OK try this on for size. If you applied mylar to the bottom of the wing fairly airtight and well attached then made 2 holes in the leading edge of the wing behind the prop wash could you get the effect of a semi symetrical wing profile if the prop wash would pressurize the wing? [8D]
Or just fill it with helium? I think that is what I need

Woodsy

I know theres a guy in the UK that just uses cling wrap on the wing to give it a flat bottom, cheap and easy to replace.

for decent LG there is only one option IMHO http://www.millenniumrc.com/X-Gear.html

jeffie8696

Wonder how that landing gear would look on my ME 109 profile control line .061Norvel plane. Might match the scale pretty close with just a set of covers

tam popo

Jeffie - Woodsy mentioned the guy in the UK - its ME My SS has 2 wings (one normal, one not!!). The flat bottomed one is cut-off by about 2in. at each wing-tip and has servos taped in from above to give aileron control - you don't need this though as stock is just as good. However, get some polystyrene and cut it into 3in. wide strips, 1/2in. deep and the length of the wing. Just add the 'styene using small amounts of your fave epoxy/glue so that when you add the 'film' to the underside of the wing it has something to rest on. I found that contact adhesive sheeting is the best - its sticky back and decorative. Just wrap over the leading and trailing edges to finish. I live in a wind tunnel called Glasgow and this SS flys a treat on an E-Max 2822 (10 x 5 prop), and 1300 3S lipo. I still keep the old wing for 'mishaps' so I can still continue flying - I can't recommend this enough.....

Byeeee......

jeffie8696

Thanks for the info. My 'stick is undergoing major reconstructive surgery at the moment.
Would you say the modified wing is easier or harder to fly?

FERNDALE AIR FORCE

Since we are discussing the SS wing and the landing gear, and since the SSX LG has been mentioned, Here's a vid of the SSX in action yesterday http://www.badiusownersclub.com/vide...Take%20One.wmv

Tim

jeffie8696

Cool!! Thank You.

Woodsy

Hi Tam thought you might chime in

longbikez

Could anyone provide me with sketches or measured drawings of the original SS wing and talifeathers. I would like to build up a Wright Flyer from a RadicalRC conversion kit and would prefer to make my own. Just don't care for the factory paint.
Thanks in advance.

Bundubasher

[quote]ORIGINAL: jeffie8696

OK here is one for the engineers out here. The Stick has an airfoil with an open bottom. Would there be more lift if it had a flat bottom? I would think this could be done with some mylar and kept fairly stiff. [8D]



Why add more weight and spoil the very aerodynamics that enable you to fly slow? Mylar will add a lot of weight.