GoeKeli

My Feedback: (18)

Curiosity has got me. I want to figure out what the wing area is of my plane. Is there a formula? I'm almost positive knowing this will not make my plane fly any better, but I just want to know.!~)

Joe Kelley

dirtybird

My Feedback: (5)

Wingspan X wing cord = wing area. If in inches divide by 144 to get sq ft. I like to keep my wing loading within 20-24 oz/sq ft. Makes them land better. Thats powered airplanes I am talking about. Gliders will be less

GoeKeli

My Feedback: (18)

Thanks Dirtybird, not sure how to plug in those number though. Here is one of my wing halves,
40.5" long 10.75" at the tip and 21" at the fuse. Of course this is a mid wing and the fuse at the wing part should factor into something. Any idea how to figure this?

Joe

Cobra1

My Feedback: (42)

Measure the cord of the wing half way out which would be about 20" in your case to get an average cord then multiply by the wingspan including the fuse. That will give you what you need.

GoeKeli

My Feedback: (18)

Thanks Cobra, I the half way point is 15 5/8" and the wing half is 40 5/8" x them and is approximatly 630 sq." times two and thats 1259 sq.". That does not include the area through the fuse. Is that considered part of the wing? I think manufacturers include that. I'll go figure that out now.

Joe

GoeKeli

My Feedback: (18)

OK, using your mid point calculation, the center bottom of the fuse comes to 178.5", add that to 1259" and get 1437.5 sq.". This sounds like a very close and resonable number from looking at it and flying it next to other planes in the 1100 sq." range.
Using dirtybirds calculation for wing loading I get 1437.5" divided by 144 = 10.0 ft.. The weight is 19lbs 6 oz, that comes to 310 oz. divided by 10ft = 31 oz per foot wing loading. If this is off, please someone correct me.

I just want to know this out of curiosity. I don't fly numbers, brands, computer keyboards or being right or wrong. I fly model airplanes!~) This plane flys better than any I have ever owned and slows to a crawl. There are many other factors that come into play besides wing loading.

As a note, I have a model that has an advertised wing area of 1157 that has a 31oz per foot wing loading, that flys like a brick. It's a nice brick and I do the best I can with it!~) Does anyone know about renolds numbers and how they come into play as planes of this size get just a few more hundred square inches larger wing area, and fly much much better? The wing and airfoil design is dramatically different between these 2 planes even though they are both extra.

Joe

pettit

My Feedback: (23)

Per your PM, the numbers look fine to me too.

GoeKeli

My Feedback: (18)

Thanks Dick!

Joe

BasinBum

My Feedback: (2)

Joe,
There are several wing area calculators and wing loading computers available online. Do a little Googleing but here is a sample of one I found:
http://www.flyingsites.co.uk/downloads/wingloadcalc.htm

Hope this helps.

Stick Jammer

This totally depends on the size of the plane. Large planes can handle a higher wing loading and still land like a trainer. There really is no steadfast range.

rmh

Look at application of model first - then look at wing loading
31 0z ft is fine for 2000 squares -flyiing with a 150 .
BUT 31 0z ft is no good for a dedicated hover /slow rolling 3D setup at 1000 sq in.
The RN Reynolds Number is a number built from speed/air density and the size of the airfoil (chord)
Also, a very short wide chord wing may be much better than a traditional tapered wing - both with same loading and root chord.
It all has to do with application -which is another way of saying "in what speed envelope are you using this setup ?"

GoeKeli

My Feedback: (18)

Thanks for your reply Dick. This is a comp-arf extra 330 2.3 and so far it has the widest flight envelope that I have ever flown in a gas setup. My electric stuff still can out best it. As we collect and crunch these numbers I believe your right. The application, wing and airfoil shape and RN. If we want to apply these in a real world way to our hobby there is a missing process in our equation. You are absoultly right that at 1000 sq." an aerobatic plane at 31 oz WL is a brick. But at 1500 sq" the same design can be a fine performer with a wide speed envelope. My observations of this plane have been in hot weater 100 degree + or - with low and high humidity.
Do you know what I mean? There is at least one or two things missing in a formula for true flying performance. Wing loading, size and RN. Not that any of this will get me better scores or whatever. Just curiosity of design.
BB, thanks for the calculator. !@~)

joe

mglavin

My Feedback: (31)

My formula for wing area goes like:

Root chord + tip chord / 2 = chord avearge, chord average x wing span = wing area in square inches

10.75 + 21 = 31.75

31.75/2 = 15.875 chord average (CA)

15.875 x 40.5 = 642 per wing panel

642 x 2 = 1284 wing panel area (WPA)

plus 21" (Root length) x the fuse area/width = Fuse Area (FA)

WPA + FA = Wing Area

T28RON

My Feedback: (32)

I have a Sig Extra 300 XS with the moki 2.10. Am wanting to do 3D and would like to know if the wing load will handle it. The wing area is 990 sq in and the plane weight is 17 lbs. I called Sig and they could not tell me what the max wing load factor is?????
Ron.

coony2787

My Feedback: (33)

How can you figure in the fuse ? It does not have any symetrics to it at all !! Only the wing has lift ?


Chad

dirtybird

My Feedback: (5)

No matter what the size or shape of the airplane is, it will land better with a lighter wing loading

Stick Jammer

That's a wing loading of 39.5 onces per sq. ft. Awfully high for a plane that size.

mglavin

My Feedback: (31)

I don't have the answer on this, it simply is atypical with all my models... And while the fuse is not shaped like the wing it is a lifting surface.

Check a few of your models, you'll find the advetised wingspan is factored to offer the wing area of your model.

T28RON

My Feedback: (32)

Chad: I did not figure the fuse. Am I confused. Was this msg for another member. I am new at this site and havn't masterd the threads yet. Sorry. []

Ron

coony2787

My Feedback: (33)

I was just asking in general how you can figure in the fuse to a sadi wing area. I think that manfactures figure in the fuse so that a said model will have more wing area on paper.

I think you are right to not figure in the fuse. If you figure wing area in my opinion you should only figure the actual wing. I cant see how a fuse can have any lifting abilaties to it. I'am sure it has alot of drag.

I'am just trying to figure it out how manfactures come up with this big wing area and then when i figure it, it comes out something else that is usually less , unless you go to carden or other big name companies and they have the same figure's that i come up with.


Chad

T28RON

My Feedback: (32)

I called Sig and talked to there tech and he has the same plane with the a gasser that weighs 52 oz. The plane weighs in at 17.5 lbs and he states that he has been flying 3D for 3 years with out a mishap. He could not tell me what the max. wing load is. I don't get that! They should have the specs on that plane somewhere. Is there a way of figuring what the max would be?.


Ron.[8D]

BasinBum

My Feedback: (2)

The fuse has is included because it is a flying surface. Without rehasing the "what causes lift" thread from the Clubhouse forum you can think of angle of attack as adding to the lift of all the surfaces including the fuse. Think about it in terms of knife edge flight. A plane with a taller fuse seems to knife edge better, why? Because more surface area to provide lift.

Ron,
At 17.5 lbs. I can tell you that Extra is a beast. Do you have a smoke system and redundant batteries or something? Did you need to add lead to balance it? I'd start getting rid of anything that isn't essential and lighten it up.

T28RON

My Feedback: (32)

The Plane has the moki 2.10 that weighs 48 oz. I have 2 sub-C cells to acticate the glow driver (operates on low idle only). I have a 24 oz tank (empty weight). A (5) sell 6V battery pack, (7) standard size servos (BB with metal gears), 1/4 scale fuel filter and fuel filler, a Cline regulator, (2) push pull switch harness's, A volt watch and 14 oz of lead in the very tail of the fuse. (the plane is nose heavy with approx 10 degree down) a Metal spinner and a bust pilot.

Ron

BasinBum

My Feedback: (2)

How does it fly? That 14 Oz. in the tail seems like a lot. I'd start moving everything back (batteries). How does the engine run without the on board glow and regulator, maybe you could dump that stuff. You don't have the rudder on pull-pull by any chance?

T28RON

My Feedback: (32)

All of the batteries are back as far as they will go without loosing resistance. The glow driver is there for 3D flying at low speeds so that the glows don't shut down or loose current. The regulator weighs apprx 1 oz with the wiring and is there for constant fuel flow at what ever throttle setting your at. This involves making all the fuel flow connections the large size fuel tubing. the fuel tank is center lined with the carb however you don't need the regulater if it is center lined but is there for better performance and back up. I do have the pull pull rudder. The plane flys like it did with the Saito 150. The engine is not broke in yet as it will take 4/5 gallons of fuel to get to peak rpm. I used 1-1/4 gallons of fuel on the bench getting it ready for flight. (5% nitro). I am pulling an 18 X 8 prop during break in and am pulling 7200 rpm. It flys well however is not broke in enough for 3D. I have been reading the threads on RCU and all of the set up and advise came from approx 5 sources. Some say fly now with the 18 X8 prop and others say fly with the 20 X 10. I do realize that each time I fly it I vhave to retune the carb as it picks up rpm. The consensus of opinion is to run it rich until it has gone thru 4 gallons of fuel and not to run it over 6500/7000 rpm unitl it is broken in. The engine is inverted and is a bear to start. The trick is to flood the carb until it runs out the carb (not drip but flows) and it will then start on one flip of the prop counter clockwise. The 150 I had in the plane weighs 36 oz compared to the Moki at 48 oz. It is my opinion that the plane should run well with A moki 180 however I am not sure that I would loose that much weight to see any great diff. All of the installations for the moki 2.10 came from those on ebay. I know that a lot of the flying ability depends on the pilot. I am not the WGA but do know and understand the basics of flight. Have been in this sport building, and flying for over 13 years. Again the only person that I can relate to flying the same set up is the guy at Sig. Hope this helps and really do appreciate your time with me. thanks.

Ron.