1:1 scale Mars Ingenuity Helicopter

[NickRehm]

I don't know if this is going to work, but I figured posting here would give me more motivation to push through the challenges.

CAD design and 3D printing parts underway now:

My goal is to 3D print as many parts as possible. The blades will be made of foamboard and I'll try to keep the assembly as light as possible to reduce power requirements and stresses on the blades. While not staying true to the real Mars helicopter design entirely (very complex rotor head design), I would still like to see a large, flybarless coaxial heli flying by the end of this project. My design is sort of a copy of early RC coaxial helicopters with the motors and transmission at the bottom, and only the lower rotor blade has cyclic control. Upper blade is fixed pitch. Yaw control through differential RPM

Did I mention this is 1:1 scale? How cool would it be to have my own copy of the Mars helicopter flying down here in Earth conditions. Stay tuned...

 

[NickRehm]

More pics of CAD assembly...lots of parts are just mockups. Just a big 3D printed fuselage plate for motor and servo mounting lol. Belt drive 700kv(?) motors with about 4:1 gear ratio to give ~1000rpm head speed. Very low, so will be interesting to see if I can stabilize this thing... Trickiest part is the 3 concentric shafts: one for each rotor, and the third all the way up to the solar panels (mine won't have real solar panels, just for aesthetic purposes).

Tried to simplify the swashplate as much as possible and still make it strong enough to be printed. Sandwiched in there are two thrust bearings between the rotating bit (tan) and fixed bit (grey). The black part is a 'ball' that's glued to the shaft and the tan bit floats on to give rotation. Control horns on the tan piece lead up to more on the blade assembly, which is free to pitch. Trust me, I'm an engineer....

Start placing bets on if this things flies or not

 

[GrizWiz]

Very Cool!

 

[NickRehm]

For reference, here is the rotor head assembly of the real thing. Motors are mounted in line (direct drive) with the rotor shaft 'mast tube' that lets them run all the wires through down to the fuselage. Both rotors have collective/cyclic. Mine is FARRRRRR simpler (not meaning better, just my overall approach is simplified to see what I can get away with)

 

[JasonK]

given the 1:1 scale, are you doing anything to to account for the gravity and air density differences for its targeted flights vs here on earth?

 

[NickRehm]

given the 1:1 scale, are you doing anything to to account for the gravity and air density differences for its targeted flights vs here on earth?

Good question. No I'm not really.

The original design leaves plenty of margin for me to make a heavier, less efficient version for Earth conditions. Real version has insane head speed and the highly cambered blades to generate enough lift in the Martian atmosphere. I'm using the same blade geometry for aesthetics, but less camber so I can still get a decent head speed with much more atmosphere down here. Gravity differences don't matter nearly as much. I do anticipate being over weight, but having so much more atmosphere helps in generating sufficient lift

 

[Phin G]

I don't know if this is going to work, but I figured posting here would give me more motivation to push through the challenges.

CAD design and 3D printing parts underway now:

View attachment 194339
My goal is to 3D print as many parts as possible. The blades will be made of foamboard and I'll try to keep the assembly as light as possible to reduce power requirements and stresses on the blades. While not staying true to the real Mars helicopter design entirely (very complex rotor head design), I would still like to see a large, flybarless coaxial heli flying by the end of this project. My design is sort of a copy of early RC coaxial helicopters with the motors and transmission at the bottom, and only the lower rotor blade has cyclic control. Upper blade is fixed pitch. Yaw control through differential RPM

Did I mention this is 1:1 scale? How cool would it be to have my own copy of the Mars helicopter flying down here in Earth conditions. Stay tuned...

If you could pull this off than send this as an application for NASA. Hats off to you in advance. Good luck.

 

[PsyBorg]

Good question. No I'm not really.

The original design leaves plenty of margin for me to make a heavier, less efficient version for Earth conditions. Real version has insane head speed and the highly cambered blades to generate enough lift in the Martian atmosphere. I'm using the same blade geometry for aesthetics, but less camber so I can still get a decent head speed with much more atmosphere down here. Gravity differences don't matter nearly as much. I do anticipate being over weight, but having so much more atmosphere helps in generating sufficient lift

I wonder how long the mars one will last. Temps effect lubrication and things need regular oiling over time no matter how sealed something is. High RPM will require seriously over designed parts not only for balance but wear and tear. Then there is the dust n dirt factor after seeing the first rovers regularly covered in fine dust. will be interesting to see the results they get.

I'm gonna bet you will have more success in the long term. (well.. unless you fly like I do )

 

[LitterBug]

I wonder how long the mars one will last. Temps effect lubrication and things need regular oiling over time no matter how sealed something is. High RPM will require seriously over designed parts not only for balance but wear and tear. Then there is the dust n dirt factor after seeing the first rovers regularly covered in fine dust. will be interesting to see the results they get.

I'm gonna bet you will have more success in the long term. (well.. unless you fly like I do )

I bet @Rcjetflyer2 has way less control and video lag too.. :-D

I wonder how big of a dust storm it whips up from the propwash??

 

[PsyBorg]

I bet @Rcjetflyer2 has way less control and video lag too.. :-D

I wonder how big of a dust storm it whips up from the propwash??

I wonder more how long said dust will take to settle after it gets stirred up before they can see again and how much of it will cover the rover shortening ITS life span.

Kinda wonder if they actually thought all this out ahead of time.

 

[LitterBug]

I wonder more how long said dust will take to settle after it gets stirred up before they can see again and how much of it will cover the rover shortening ITS life span.

Kinda wonder if they actually thought all this out ahead of time.

Proof of concept. 1 flight will be a win.....

 

[PsyBorg]

Proof of concept. 1 flight will be a win.....

which is a PoC? the real one or the one we are discussing in the thread for earthly efforts? and yes one flight on either would be a win.

 

[LitterBug]

which is a PoC? the real one or the one we are discussing in the thread for earthly efforts? and yes one flight on either would be a win.

Some of the NASA engineers were calling it a technology demonstrator, which is just a fancy name for proof of concept.
rotorcraft.arc.nasa.gov › filesPDF Web results Mars Helicopter Technology Demonstrator - NASA Ames Research Center Aeromechanics

 

[NickRehm]

Kinda wonder if they actually thought all this out ahead of time.

Something tells me they did

 

[PsyBorg]

Something tells me they did

I just know what mine look like taking off from the gravel infield at our local park when its been dry a while. I cant imagine lifting off in near desert conditions let alone the hang time of particles in low pressure atmosphere. Be like Bugs Bunny and Daffy Duck in that episode where they were movie stars and someone would yell "MAKE UP" and this hand would come into view and whack them in the face with a powder puff that would fog the room hehe.

 

[NickRehm]

Parts coming off the printer and in the mail. Already gone through a few iterations on the prints to get tolerances right. I also started cutting the blades out. I'm using the exact same geometry as the real one, stolen from a NASA design report and traced onto foamboard. My plan is to double up the foam and sandwich the pieces over the 5mm carbon spar and some small root inserts. Then go back and bevel the leading and trailing edges. Might remove the outer paper if that's strong enough, but we'll see. I'm consciously ignoring blade balancing for now....just want to get this whole thing put together to start identifying design problems before focusing on ones I know I can fix.

 

[PsyBorg]

Man I see everyone using 3d printers for everything these days.. I could see my self locked in a room with one of these too broke to eat and only enough spare cash to keep the electricity on to print. I have soooo many ideas I would probably go insane (or actually more insane in my current winter state blahs state) just trying to sort them out and make a prioritized list.

I see you are laminating the props? what rpm range are you planning with these? obviously not near as fast as what they need on Mars but still foam for props does not seem like a viable material for spinny things in my head.

 

[NickRehm]

I was very against the '3D print everything' mentality early on with the 3D printers, but without a proper workshop at the moment, it makes manufacturing easier... Ideally a lot of these parts should be machined or lasercut--I just don't have access to those tools. So I thought it would be fun to design for 3D printing to gain a better understanding of the strengths and weaknesses

The plan is about 1000rpm head speed (~16 rev/sec)...Very slow for a heli of this size, to prevent the foam blades from self-destructing. But that poses a new problem: controllability. Such a low head speed will make stabilizing this thing a challenge...

Worst case I end up with a cool looking Ingenuity helicopter model that can't fly, I guess

 

[PsyBorg]

I was very against the '3D print everything' mentality early on with the 3D printers, but without a proper workshop at the moment, it makes manufacturing easier... Ideally a lot of these parts should be machined or lasercut--I just don't have access to those tools. So I thought it would be fun to design for 3D printing to gain a better understanding of the strengths and weaknesses

The plan is about 1000rpm head speed (~16 rev/sec)...Very slow for a heli of this size, to prevent the foam blades from self-destructing. But that poses a new problem: controllability. Such a low head speed will make stabilizing this thing a challenge...

Worst case I end up with a cool looking Ingenuity helicopter model that can't fly, I guess

Have faith my friend. If faith doesn't get you in the air remember. There is no problem big or small that can not be cured by the proper application of plastic explosives. You can build it WE can get it to fly!!!!

 

[PsyBorg]

This might interest people following this project. Its kind of relevant even if it was meant for the moon. I am sure some of this transposed to the Mars mission.