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How to do what I want without using a 3LS design ?

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Swampyankee

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Dec 25, 2015
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Forward sweep isn't common because it tends to require much more torsional stiffness. While there are advantages, especially at high angles of attack, when compared to sweep back, a swept-forward will will need to be much stiffer than a straight or swept back wing to avoid aeroelastic divergence. Also, a swept-forward wing tends to need more dihedral.

Forward-swept wings tend to have pretty good stall characteristics; they don't have the pitch-up issue that swept-back wings have; forward sweep tends to reduce the loading on the tips as angle of attack increases.
 

rbarnes

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Aug 28, 2015
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Texas
Unless you've got a good idea of the weights of everything and where the CG comes out, it's probably too early to know if you'd need a forward swept wing.
Yes the weights of the engines I want to use are well documented. I only want 2 seats and a bag area, so the CG range doesn't have to be huge.
 

Riggerrob

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Sep 9, 2014
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1,543
Location
Canada
Pond Racer had twin booms because they needed plenty of volume for superchargers and cooling radiators. The engines never produced their promised horsepower and the pilot was very busy closing radiator flaps, monitoring temperatures, pressures, etc. Sadly, it is rumoured that the pilot was asphixiated by a coolant leak. That was the only time that one of my clients died while wearing a parachute that I packed.

Returning to the OP's mission: who says that you need twin booms?
Consider the assymmetric Blohm&Voss 141 recce plane with its engine on the front of its single boom and the crew in the quiet godola.'
Also consider Dan Raymer's speculative light twin with one tractor and one pusher engine.

A caution about solidifying configuration before a careful weight and balance study. Consider that Avanti may have 3 flying surfaces but they work more like 2.15 with the last bit of the main wing (canard) installed in the nose for balance. Avanti split the main wing to simplify construction of the pressurized cabin. Business jets and airliners now pass the main wings' structural box under the pressurized cabin and install a "canoe" faring where at the junction. The disadvantage is that "stacked" wing and pressure cabin can look silly on small airplanes ... silly as in an unusually deep fuselage ... creating too much profile drag. The Avanti's rear T-tail works like a conventional airplane.

Also be cautious about stagnating on a forward-swept wing too early in the design process. Most swept forward wings are to compensate for balance problems. For example, the Hansa jet has forward-swept wings so they could install the main spar aft of the pressurized cabin.
Personally, I would start with a Boomerang or assymmetric configuration (e.g. one engine in its won nacelle), do a preliminary weight and balance, then decide on number and planform of wings.

Did I throw out enough ideas to confuse you?
Hah!
Hah!
 
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