I have a character with 2 pairs of mechanical engined wings and I have been wondering if they’d even work or what would be the best type of wings for this character. They’re a military fighter, heavily armored. I was wondering what would be the best engine placement on their wings, as they need them to not be vulnerable to being destroyed in both aerial combat and ground combat. Their current wing design is as shown in the image below. Their primary wings are roughly 24 feet long and 7 feet wide, secondaries are 15’5 feet long and 5 feet. The characters overall weight is unspecified as I’m not sure how much weight these wings could support, as they’re meant to be abnormally heavy as weight gives an overall combat advantage. Weight should be as high as the wings can support. Flight speed is not meant to be fast, just faster than 15 miles an hour. Their flight method is using the primaries for most maneuvers while the secondaries are for steering. Wings will flap in unison in flight. Engines will just for easiness sake use unlimited fuel. Primaries will need to be armored as they use the wings to both shield and attack in air and ground, secondaries don’t matter as much. TLDR: What engine placement would be best, would such wings be able to work and how much weight could they support?
A few changes.
There is no reason to have two overlapping wings, they will just get in others way, a flight stroke needs a lot of space. So you would either get rid of one set of wings or make it so they do not overlap. the closest you could get would be two small control surfaces sticking out of the back. Nothing that flies has widely overlapping wings, there is just no benefit. Bat like flapping flying machine have been built just nothing on this scale.
Mass wise you should be fine, the largest animal to ever fly weighed around 400lbs and had a 36ft wingspan.
Bird wings are the LEAST efficient wing design, something like bats wings will work better. Worse bird wings need a lot more moving parts which will work against you with a mechanical system. Doubling or tripling the complexity of a mechanical system for no gain or worse is always a bad idea there is no way around that one.
Flapping flight is a LOT quieter than any other system so that alone may be enough reason to use it militarily. But another benefit is it will be very maneuverable, a skilled pilot will be able to do things no rotorcraft can manage. Downside this needs about twice the area than a single person rotor wing craft would need.
One side note, your human will need some kind of lower body powered exoskeleton both to keep their legs steady during flight and to bear the weight of the thing on the ground. This could help a lot with takeoff and landing as well.
Provided your motor/power source is compact enough and the computer control system is good enough this should be possible. we have good enough computers and maybe good enough material science, but right now there is no power source or set of actuators that will fit the bill. So those will have to be science fiction. Your power system will be close to the center of mass, essentially where the bottom of a backpack would be on a human.
But this thing will never be heavily armored, armor is heavy. It could be more heavily armored than a normal soldier but that's about it. You just don't have weight to spare. Up side a few bullet holes in the wings will not stop them from working.
Essentially you're going to need to build a robotic giant bird musculoskeletal system with extreme super-strength. Large servos or pneumatic muscles where the bird's chest would be will do most of the work, just as a bird's chest muscles do most of the work for the bird.
Such a design would be hugely inefficient compared to something like a helicopter or quadrotor or even a jetpack for the role of small scale low speed flight. There's a reason all large birds are walkers, swimmers, or gliders, not flappers: the square-cube law ruining fun as usual. Strength scales with cross-sectional area, while weight scales with volume. If you scaled a humming bird up to the size of a man, it would drop like a rock.
I would suggest making the wings run on magic (or Sufficiently Advanced Science) and of some mysterious origin. A bizarre old weapon from the lost armory of Atlantis needs no explanation (except for why it's being fielded in battle, not studied in a lab, but that's easy to get around - maybe there are hundreds of them and some got sold off, or the operator stole it from the lab, etc). A cutting edge military aircraft that's the least useful conceivable application of the technology required to build it, and is somehow also the only application of the advanced technology required to build it, admits no explanation.
Marvel had the right idea with Captain Falcon. Put the engine (propeller) on the head.
"Show me your moves!"
Head down and wings outstretched, you fly like a biplane.
Though I suggest you improve on Marvel's design by enlarging the propeller for extra pu-zoom!. See the mockup below.
For what you've described - you have two competing ideas:
- Human powered Flight
- Heavy Armour
These are mutually exclusive. However, reading your question, a thought came to me - such a wingspan, supporting a typical Human would be more than enough to have a pretty good glide span - and you've already said there is an Engine of sorts.
In order for the Human to have some degree of Body-Armor (I'll cover off the wings in a mo) - it would be entirely possible that the type of 'flight' such a character would use could be considered 'Rocket Assisted Gliding'.
That is - the user would use a small but very powerful rocket motor to take off, with an almost ballistic trajectory, wings folded for maximum speed like a Peregrine falcon in a dive. Then after a period of time (10-20 seconds, however long to achieve a decent height) the Rocket cuts out and the wings extend and the protagonist glides (and doesn't flap) for a long distance. This solves 2 key problems:
1: There is now no longer a need to flap - so all that heavy exo-skeleton, powered actuator nonsense isn't needed and
2: We've seen how far someone in a Wing-suit can glide (3:1 - 3 metres forward for every metre dropped) - a larger wingspan means you could approach Glider-esque slopes of 30:1 or even as high as 60:1
A Modern glider is hitting 400-600 Kilos with an 18 Metre Wingspan - so let's say that we go for a total weight of 200 Kilos (wings, Armour, Aerodynamic cocoon), the Wings are semi-rigid and don't flap - we use a Rocket Motor to power the wearer up to about 3 Km/10,000 ft and they then glide to their next destination (assuming no thermals or other tricks to stay aloft) around 100 km away - I think you've got a reasonably believable setup.
In terms of Armor for the wings (I said I would get to it) - No. And there's a reason 'no': An un-armored surface will result in most projectiles and attacks poking a nice, neat little hole in it. Adding anyform of armour will mean that a projectile will either arm itself (if it's an explosive charge) or it will spall/deform and cause more damage than if it was unarmored.
You can see this in WW1 dogfighting where the canvas covering of an aircraft could have multiple holes in it but still be fine, in WW2 dogfighting where the survivor-bias study showed that damage to non-critical surfaces where the bullets/shrapnel punched clean through still allowed the Aircraft to get home - or even WW2 Naval engagements - I can't remember the ships, but I seem to recall a Destroyer took a large calibre shell (possible 8 inch?) through the funnel - and there's a picture of a clean hole eitherside as it zipped through causing minimal damage.
For a comparative feasibility study, the largest flying animals today are 30-40 pounds. The heaviest flying animals ever are varieties of pterosaur with weight estimates between 150-500 lbs. Obviously, these are extinct and nobody was around to make records, so we can only speculate about the biomechanics of these creatures based on their fossilized skeletons.
It is unknown whether pterosaurs were capable of fast, dynamic flight, or whether their wings were used for slow, soaring flight, or perhaps they were only gliders or even could have been flightless. Different studies have come to different conclusions.
The heaviest flying bird today, the Kori Bustard, clocks in at 30-50 pounds and is kind of a miniature ostrich. It spends most of its time on the ground, but can fly for short periods to escape predators. Other large birds do fly a lot, but are lighter, and they all tend towards "soaring" rather than "flapping." They don't spend all their time doing acrobatic maneuvers, and their flight is optimized to conserve energy while probably also taking advantage of thermals.
In terms of translating this into a human system, the US military requires a 6 foot tall 17-27 year old to be at most 195 pounds. In terms of modern armor, the military uses a combined soft and hard armor system that weighs around 35 pounds, but this could be reduced ~15 pounds without the heavy plate inserts designed to defend against powerful armor-piercing bullets. This is 230 pounds with only the person and the armor, but does not include a weapon, the wing system, or any other supplies such as food, water, tools, etc. Again, using the military as a frame of reference, soldiers routinely carry 50-100 pounds of gear depending on situation, for a total weight of up to ~250-300 pounds, not including the wings.
And remember, your human has to not just bear all of this weight on their own two legs (unless they have something helping them), they also need to be able to absorb the impact of dynamically landing with all that weight on them. Again using the military for comparison, the risk of serious injury for parachutists landing with combat loads may be as high as 5-10%.
I would not worry about being overly technically correct here. Using the pterosaur model, the situation you describe is plausibly feasible, but subject to constraints. It's probably the case that slower, soaring flight is more feasible than dynamic, agile flight. Size is an issue- looking up Quetzalcoatlus and Hatzegopteryx, these are estimated to have 35-40 foot wingspans, weigh 400-550 pounds, and are essentially as large as a small plane. Leg bracing or some other method of absorbing the impact of repeated landings seems important. Armor and other gear is limited, and every ounce counts.