On the surface the efficiency gain does seem suspiscious. However if you look further into it, you'll note that the claim is not unreasonable when you consider drag reduction in removing a tail, fuselage even and factor in some increases in efficiency from Ludwig's forgotten second set of equasions.Matteo V wrote: ↑Sun May 09, 2021 4:07 pmLove the revisitation of the same old questions. And the tackling old research with new advanced methods is awesome.
60% gain in efficiency??? Ummmm.... so now we need to expand all of our airport terminals to 3 times thier current size to account for the additional wingspan? And how are you going to design an aircraft carrier for just one of those flying wings?
I agree! The adverse yaw though, I don't think I've hydrofoiled fast enough for it to be an issue.. I steer with the hand wing too.Herman wrote: ↑Sun May 09, 2021 10:52 amI loved the link, I can blame a whole lot more on adverse yaw instead of my ageing balance sensors. It staggers me to think how good Ludwig would have been if he had access to modern computer modelling etc. I think the WW2 Spitfire was famous for its elliptical wings.
Thanks Gestalt, Humpback tubercles like Takuma are copying seem to be a larger scale more manufacturable solution. Wings with waves from the centre to the tips might be another solution, I've been working on my own software to produce this sort of effect like my current icon on here.
If you squish a 747 down to a highly efficient wing with the same passenger capacity, what is its wingspan?
Hmm.Matteo V wrote: ↑Mon May 10, 2021 3:25 amIf you squish a 747 down to a highly efficient wing with the same passenger capacity, what is its wingspan?
Look at those models gaining 60% efficiency and let me know where you think the passenger compartment is going to go, and how wide a runway you will need to accommodate that width for landing gear support.
Again, practicality is the reason we have 747's that look the way we do - it's not because we are missing something in aeronautical engineering.
As for vertical winglets being inefficient.... how about the problems with increasing wingspan for horizontal winglets, in regards to increased load/leverage in turbulence at high angles of attack? Vertical winglets have the benefit of not adding to wingspan, and not increasing load with a sudden increase in angle of attack - because they are vertical.
I'm amazed at how people get caught up in "new and improved" hype only to see it fall flat on its face. This is truly the "solar roadways" of aeronautics.
I skimmed this..... so what you are saying (picture me in a Cathy Newman wig) is that this innovation is not practically applicapable..... making it unfortunately.... IMPRACTICAL? Just like "solar frickin roadways"!fluidity wrote: ↑Mon May 10, 2021 7:28 amHmm.
Mateo, fair or not you remind me of an argument I used to have with a hobby shop owner about jet units for small radio controlled boats.
He played your part, asserting that if it could have been done it would have been done already, that it was a waste of time trying and that the surface area to volume ratio in a small jet unit was prohibitive to performance.
I played the inventor role, taking offense at the idea that everything workable had already been tried and the guy has since been proven wrong by hundreds of DIY modellers. Perhaps he forgot to consider the ant-effect? where the smaller the moving thing is, the less of a column of material needs to be supported by each unit of area lifting it.
Anyway, back to your assertion that it's likely to fall flat on it's face.( A Prandtl wing)
I think we both see that when you remove the fuselage and change to a delta, you need to replace the people and cargo carrying volume with in wing volume? Agreed? (and this is completely ignoring that it's the tail and rudder that can be most conveniently dropped, dropping the fuselage depends on providing an alternate high utility space within the wing volume)
So in a conventional plane, the fuselage plays only a small part in lift. It's designed for high volume to surface area ratio and streamlining, minimum length for airport parking convenience and structural integrity, long for reducing the displacement motion of air it passes through, fairly constant length to provide a tidy architectural home for the nosy window-gawping payload, rounded in cross section to reduce total area etc. These are compromises that have been refined over the decades and that are still subject to minor improvements. Passengers tolerate side windows
We both also agree that an airport provides constraints. Constraints on wing span, on taxiing wheel base span, on take off length in the most unfavourable conditions and landing constraints dependant on cross winds and time for the aircraft to slow to a taxiing speed. Within constraints of a maximum wingspan, Ludwig's first formulae for eliptical wings makes sense.
Sizing the aircraft smaller than max lift for the total permissable wingspan the bell shaped curve pointier wings of Ludwig's later theory makes more sense as it's only in max lift for a constrained span that the eliptical shape excels.
We've both seen the open V variants of deltas that are being trialed at large model size at the moment by Bower's team. I think it remains to be seen whether they can safely deal with high cross wind landings. I think enough of a filled in delta or fuselage pod is required to allow for rear wheels to lift the plane behind it's centre of gravity. For small Prandtl wings with no fuselage this is not an issue. However, cargo volume in a normal fuselage would of necessity be relocated into the wings and I don't think any of us have quite got our heads around the best re-packaging for that. Within the constraints of an undercarriage that can fit with safety allowance on a runway speed surface, max wing span and undercarriage to suit, there is potential to redo the whole delta concept utilising the advantages of a proverse yaw design. It may well not be at 747 capacity! However I think it would be foolish to write off the possibility of very successful passenger and cargo carrying Prandtl wings on the basis that non Prandtl delta wings had some major issues. In my opinion the biggest problem is still going to be active yaw control in high cross winds.
I don't agree but that comes down not to the data, but to different ways we look at things. If you were to look up your own Myers Briggs type and compare it with mine of ENTP it would make perfect sense, we have skills and talents in quite different areas.Matteo V wrote: ↑Mon May 10, 2021 1:31 pmI skimmed this..... so what you are saying (picture me in a Cathy Newman wig) is that this innovation is not practically applicapable..... making it unfortunately.... IMPRACTICAL? Just like "solar frickin roadways"!
And let me just say that it gives me no pleasure in being right in repeatedly pointing out a destructive psychological characteristic in the vast majority of the human population. Especially when I cant seem to even fathom a possible solution for our clamoring blindly toward new flashy innovation that creates more problems than it solves. Welcome to environmentalism, politics, 20 years of chicken loop design, and....... humanities future.
Sincere apologies for the harsh tone, we all have something that gets us worked up.
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