tl:dr; cropped from large image below (own work).
quick bash, can't find actual dimensions, details seem to vary on vehicle as evidenced by nose.
3m box for aeroshell reference
human is about 5'9" (1.75m) tall as an average
generally articles say 3m, to fit inside heatshield aeroshell.
Preliminary studies and modeling contemplate a baseline 450 kg mass for the rotorcraft packed in a 3.7 m diameter heatshield.
A constraint in this application that is somewhat unusual for rotorcraft is the necessity to be packaged in a hypersonic aeroshell.
The geometric trade of unblocked rotor disk area versus number of rotors with such a constraint suggests that, in fact, four is optimal.
the size of a Martian rover (3 meters by 3) but much faster, will be launched in 2026 and will arrive on Titan in 2034.
It will fly from point to point analyzing Titan's hydrocarbon clouds and its ethane lakes, and hundreds of kilometers in its two years of being on mission.
Dragonfly, expected to weigh around 1,200 pounds, will be the size of the largest Mars rovers.
At the end of each of its four arms, two 53-inch counter-rotating rotors, one atop the other, will provide lift.
From helicopter to quad rotor:
‘We want to maximize the disk area of the rotor, and the way we will do that is I’ll make a coaxial-rotor helicopter [with two counter-rotating propellers on a single axle] that fits exactly inside the aeroshell of the spacecraft,’
“But it turns out that you can actually get a larger net disk area with a multi-rotor, with a quadrotor.”
“When the rotors are spinning, this rotor can stick way outside the circle that defines the aeroshell,”
The reason why you go with an octocopter—with the stacked rotors—is so that you get some redundancy. So you can lose one rotor and you can still fly safely.
Basic dims., sorry got them from the usual places:
Perseverance
Length 2.9 m
Diameter 2.7 m
Height 2.2 m
Launch mass 1,025 kg
Ingenuity
Fuselage (body): 13.6 cm × 19.5 cm × 16.3 cm
Landing legs: 0.384 m
Diameter Rotors: 1.2 m
Height 0.49 m
Landing mass
Total: 1.8 kg
Batteries: 273 g
Dragonfly (guess)
Length 2.9 m
Diameter 2.9 m
Mass: <600kg
https://danielmarin.naukas.com/2019/06/27/la-nasa-elige-dragonfly-nos-vamos-a-titan/comment-page-2/
https://beyondnerva.com/2019/07/09/dragonfly/
https://www.nasa.gov/dragonfly/frequently-asked-questions/index.html
https://factburger.com/read/dragonfly-nasa-titan-adventure.39
https://techcrunch.com/2019/06/27/nasas-dragonfly-will-fly-across-the-surface-of-titan-saturns-ocean-moon/
https://www.hems-workshop.org/13thWS/Presentations/04%20Danell.pdf
https://dragonfly.jhuapl.edu/News-and-Resources/docs/34_03-Lorenz.pdf
https://www.airspacemag.com/airspacemag/skies-over-titan-180975602/
https://space.skyrocket.de/doc_sdat/dragonfly.htm
Note: I know the legs and shapes are incorrect for Dragonfly, my initial 3d was based off interpreting bad pictures of what turned out to be early concepts. I'll fix it at some point...
