Initially, it was designed based on 360 sized helis (Gaui X3) and some from Goblin 380 since anything above 380mm jump to 10mm root thickness.
The Gaui X3 stretched to 380 is common so no problem for now.
However, the grip is larger because I need to use 6mm endmill to make it. It is as beefy as Goblin380’s with same size bearings (5x10x4) which means the spindle is also the same diameter.
So the grip and spindle don’t worry me, 2 points I’m worried are mainshaft (6mm) and spindle bolt(M2.5).
To give you the idea, Goblin380 uses 8mm hollow mainshaft & M4 spindle bolt and Trex500 uses 8mm mainshaft(7mm at OWB) & M3 bolt.
Also the blades I found has 6mm root instead of 10mm of usual 425mm blades.
So my real question is: can 6mm mainshaft handle 420mm blades? (6mm root, not 10mm)
Everything else should be fine
About your X3, do you mean the EurocopterX3-shaped-heli you showed me earlier?
I go back to my previous post. if half of your full up weight for the intermeshing design is roughly the same as the weight of a 360 size Gaui X3, then I would say you’re probably ok, especially if the Gaui X3 was designed as a 3D heli. As far as the spindle bolt, I would not exceed the value of blade mass * (rotor speed)^2 for the maximum size rotor blade and rotorspeed for Gaui X3 heli. Really centrifugal force is based on inertia*(rotor speed)^2 but I think since all we can figure out is mass, that will work. It just assumes mass is distributed the same between the 380 and 420 size blades.
How much will the payload increase the weight 50% (i.e. aircraft increases from 2.1 kg to 3.1 kg). I would still feel this is acceptable. I’m running a 550 size frame (~6 lbs designed takeoff weight) and increased the weight to 13 lbs. I haven’t changed the main shaft (10 mm) but I went from a 2 bladed head with 600mm blades to a 4 bladed head with 550 mm blades. A main shaft of 6 mm does sound a bit thin. If it isn’t too much work, it wouldn’t be a bad idea to increase to 8 mm. But I think it would be ok at 6 mm. You’ll just need to hold back on the 3D aerobatics
I tried mounting my custom made gimbal + SZ100 which weight about 900g (close to 50%) and it does fly although at 65~70% stick. Headspeed can not be increased much further, it’s already equal to Protos380 RPM for sport flying.
Also found ALZRC’s 420mm blades with 5mm thickness, but Switch-brand blades manufacturer said that 5mm root is pushing the safety limit. But still, that’s for 3D helis
No longer feel like doing that
BTW I’m curious, your X3 should still suffer from RBS, shouldn’t it?
I had a quick look and EurocopterX3 beat Sikorsky X2’s speed(on paper), how does X…cubed? deal with RBS?
I would think the root was designed more so for the centrifugal loads than bending since the g’s due to centrifugal force would be much greater than the bending loads. So it would be more of a rotor speed thing but I’m not certain about that.
Yes the X3 would definitely still suffer from RBS however you can delay it somewhat because 1) you are not using the rotor for propulsive force and 2) you can offload the rotor thrust by using a stub wing. In both cases, you effectively lower the blade AOA over the entire disk which allows the aircraft to get to higher speeds than a conventional helicopter but eventually you will still see RBS.
