Recent content by yavorh

Behold: Wings MOI = ((45wingshell+15ribs)/12)*(2.5^2+.55^2) = 32.7kg/m2 *2 = 66kg m2 CoM is right ontop of CG, rounding up to 70kgm2 to account for minor differences 2x Wing Ibeams (6/12)*(.08^2+.005^2)= 0.003213 Per wing, one of the beams is on CG, the other is .6m back, the ones who are...

Had posted my results to verify validity, buuuut nevermind, forgot to do parallel axis through CG

Awesome! I just managed to find some similar info through this one book, but it wasn't as detailed on finding the CG MOI as you explained it. Thank you very much! Since I was using this given above example as a base on which to test if the formulas I'm using on my own design are accurate, I'll...

Thanks for the info thus far - I am trying to find the Mass MOI in kg/square meter about the main gear - the idea is to factor it into the calculation of how much force the elevator needs to produce in order to rotate the plane during take off. In this case I'm not sure exactly how to...

Homework Statement Okay, so this isn't so much a problem as a design issue while following an example given in a book. (Relevant material is here: http://www.aero.us.es/adesign/Slides/Extra/Stability/Design_Control_Surface/Chapter%2012.%20Desig%20of%20Control%20Surfaces%20(Elevator).pdf ) Now...

Daaang, you certainly can put down the hammer when it comes to information gathering. It is a shame that this idea will need to be put on the wayside, at least for this application of such a rotor, but I will definitely have this in mind in case we manage to find another application of it.. Low...

Hmm, yep, just doublechecked the values, the best I can get would be even less - 143 RPM... Well that idea is out the window, back to the drawing board!

Exactly! This is what made me want to double check it with other people, because when I applied the above formulas to both the Tesla example and other given propeller examples on the topic of Kv, Kt and Ke, it came out with wild numbers.

Good point. Added to research list for this weekend. Thanks for the input thus far, guys, it really is awesome and helpful. :)

Hmm... Fair point. What threw me off was looking at Tesla's Model S for reference. As they can achieve up to 500 HP on the rear drive (let's even call it 250 per wheel), with a torque of 400N.m (again, let's even call it maybe 200 per wheel), yet they are rated at 350V at 80kwh. So, I guess...

Oh, pfft, sorry... 1.7 meter DIAMETER. Through the thrust bearing: The propeller will be attached to one side, the three tips touching one ring, and the other end will be attached to the frame of the airplane. The stator, positioned around the bearing, will be also attached to the frame.

Hey Jim, The idea is that the propeller, even though it has 3 blades, will be attached to a thrust bearing - which is essentially a full ring which will be absolutely covered in magnets.. Pretty much for those 99 teeth (33 per phase) around the entire diameter of the stator, the rotor (that...

Hey Baluncore, thanks for the reply. The object in question is an airplane propeller. The 3200 RPM is its max required RPM, optimal RPM being 2600. The weight of the propeller(3 blade) is 3.5kg. The propeller is designed to be pushed by a max 60HP engine which is how I calculated how much torque...

Bump? Wrong section of the forum?

Hey there. Nah, the aerodynamics part has been covered to a good degree, I'm more baffled by a few formulas in regards to electric motors. I've posted my problem in this thread: https://www.physicsforums.com/threads/bldc-required-voltage-to-get-set-rpm-at-given-amps.907009/