But the appendix is only for rectangular wings. I'll have 114 sqft, with >50% split flaps, I'm expecting it to meet the stall requirement. If not, I'll flaperon the ailerons until it does. You don't actually have to use the flaps etc except to show compliance...The wing area requirements for ultralights are listed in AC103-7.
I missed that. You are right, post 118 has about half the wing area needed to comply with 103.70% of 37 feet is 26 feet span. His post 118 has morphed to 16 feet.
So, how do you plan to get a CLmax of around 4 that is necessary to make this concept 103 legal?All I've done is scaling and comparisons.
I do not see how you equate FAR 103 with 110 sq feet/6.8 ft chord. To me, that's like saying You have an apple and ketchup is necessary.
What is needed is a wing that will perform the necessary functions, not some arbitrary chord and area. Chord at the root, as depicted is approximately 5 ft 8 1/2 inches.
You gave a span of 16' so you established one key dimension. A P-51 has 37' span and 235 sq ft of wing area, at 70% scale that's 26' span and 115 sq ft area.
A proven, cantilever, legal Part 103 ultralight like the Sky Pup needs 31' span and and 130 sq ft of wing area to manage a stall speed of 26 mph with an empty weight of just 195 lb and gross weight of just 400 lb.
If you have a more typical Part 103 gross weight of 500 lb then you'll need about 160 sq ft of wing area. BBerson is being very generous...by my calculations you'd need an average chord of 10' to make this work at 16' span with a typical airfoil.
Run the numbers backwards... Gross weight ~500 lbs... WHY? 254 + 30 = 284 Me? I'm ~215 Voila - 499, so round up for that after meal flight? (shrugs)
Now, looking at the images... Oh, looky, there One with flaps... 1.8... Call mean chord 3.8 ft. Call it max wing loading 3.4? Use something like this...? ~9.35% thickness... (Correct?) (Oh, look, Fowler Flaps)...
Anyone want to calculate the area, then the span, based on the standard P-51 Mustang wing with a root chord of ~5 ft 8 1/2 inches, mean chord of 3.8 ft?
I'll adjust the span, then fiddle with the rest. How does that sound?
I asked for help and seem to be getting negativity. I SAID that I screwed up and over shot getting too small, because of all the comments on weight, but I guess that's not good enough for you...?It seems you know everything and reject help. Good luck with your project.
I think this is a case where trying to make the aircraft too small will make achieving the mission goals next to impossible. If I were you I'd start with about 5/6 scale (83.3%) to get the span (31 ft) and wing area (163 sq ft) you need to fly 500 lb at Part 103 stall speed with a typical airfoil. Then the challenge is designing a very light structure to create that form at 254 lb empty weight. I think it could be done with wood and foam and fabric, perhaps with some carbon fiber in the spars, longerons and landing gear legs and a paramotor engine. Basically you'd be creating a true Part 103 successor to the Loehle 5151.
Ok, so you just posted a graph at a Reynolds number that indicates 100 mph. How about one at 26 mph?
So, let's maintain that 16 ft span... 3.8 ft mac and use a calculator... Why not, seems almost the only way to get an answer around here that isn't aimed at discouraging people, right?
... which ends up being a turbine rotor blade design, because of a maintained fiction of 16 ft...
Is that 31 ft based on the changes, or a suggestion? I'm not a mind reader. Not trying to be snarky, but asking an honest question. Not sure if we both arrived at 500 lbs by the same means, but, it works.Or maybe you could read more carefully....
... and, still, I'm getting snarky comments.Frusha. The persons you slash back at probably have more time on the "shitter" between flights then you have in the air. I think you OVERLOOK on big factor with a plane you are hoping to design and build with a tail moment so short I think pitch control would be more then a pilot could handle. Why not just buy one of these and build a proven design ? Personally I'
m rather sick of dreamers that have nothing better to do then talk the walk but never mix some glue or fire up the torch. My 2 centsView attachment 85397