Project: Team Associated TC9
11-23-2011, 02:12 PM
#31
That's bitching!!
11-23-2011, 11:04 PM
#32
Nice thread, great designs. Just sharing, even Hara is testing with a drift chassis for TC racing.
Source: Xtreme RC Cars
Source: Xtreme RC Cars
12-11-2011, 11:07 AM
#34
i was actually considering something just like that for a custom car, good on you. though i was gonna use a pancar style direct drive front/rear instead of belts. very curious to see how the belts will work instead of straight up gears.
I guess your kinda stuck with belt for the rear, but i imaigne you have to make a front shaft so are you using a belt there too?
neat hybrid drivetrain =)
I guess your kinda stuck with belt for the rear, but i imaigne you have to make a front shaft so are you using a belt there too?
neat hybrid drivetrain =)
12-13-2011, 09:52 AM
#35
Hm that's an interesting idea.. I have seen a couple cars that had used a direct drive system.. My only concern was the size of spur you would need to use for a correct FDR.
Yea, I am stuck with a belt in the rear. There also will be a belt in the front.. but then the shaft connecting the two belts instead of a third belt.
Yea, I am stuck with a belt in the rear. There also will be a belt in the front.. but then the shaft connecting the two belts instead of a third belt.
12-13-2011, 10:40 AM
#37
3gear would be smooth but you lose power at each direction change, the advantage belts have.
Id use smaller gears with no downstep for rear to front. Run the shaft at layshaft height then you have room under the shaft for electronics with slight offcenter battery.
Looks good though.
Id use smaller gears with no downstep for rear to front. Run the shaft at layshaft height then you have room under the shaft for electronics with slight offcenter battery.
Looks good though.
12-13-2011, 12:06 PM
#38
I think you're being a bit too ambitious on trying to use the shaft. When the chassis flexes, the belt is more forgiving. The shaft may have issues maintaining consistent gear mesh.
I like your design of keeping everything centralized. Looking forward to seeing more progress.
I like your design of keeping everything centralized. Looking forward to seeing more progress.
12-13-2011, 02:04 PM
#39
Something to consider whilst shaft drive is noticeably more efficient at low speed at higher rpms belts have less resistance and are similar in efficiency to shaft drive.
12-13-2011, 02:35 PM
#40
I think you're being a bit too ambitious on trying to use the shaft. When the chassis flexes, the belt is more forgiving. The shaft may have issues maintaining consistent gear mesh.
I like your design of keeping everything centralized. Looking forward to seeing more progress.
I like your design of keeping everything centralized. Looking forward to seeing more progress.
12-13-2011, 03:41 PM
#41
Love the innovation!
Consider though, that every mesh you have degrades your efficiency. The best gear meshes are ~98% efficient, and not at high speed. Belt drive is anywhere from 80-90% efficient, depending on the belt wrap and the number of teeth in mesh.
For simplicity, let's say each bevel gear mesh is 95% efficient, and every belt mesh is 85% efficient. At that point you're looking at 0.85*0.95*0.95*0.85 = 65.2% efficient versus two belt at 72.3%. Straight shaft (like TC3) would be 90.3% efficient under the same assumptions.
Consider though, that every mesh you have degrades your efficiency. The best gear meshes are ~98% efficient, and not at high speed. Belt drive is anywhere from 80-90% efficient, depending on the belt wrap and the number of teeth in mesh.
For simplicity, let's say each bevel gear mesh is 95% efficient, and every belt mesh is 85% efficient. At that point you're looking at 0.85*0.95*0.95*0.85 = 65.2% efficient versus two belt at 72.3%. Straight shaft (like TC3) would be 90.3% efficient under the same assumptions.
12-13-2011, 07:54 PM
#43
12-14-2011, 07:00 AM
#44
Tech Adept
12-14-2011, 10:55 AM
#45
nrtv20: Like Valk said.. a three gear would be smooth but it would be heavy..and part of why I'm using belts is th?ey don't have instant power transfer...making them a bit easier to drive.. thanks though.
Valk: The Tc3 gears are the only gears I have available. Right now that bottom the shaft will be about 20mm from the top of the chassis.. I can put the esc and receiver under the shaft, but unfortunately, not the servo.
YR4dude: I do hear your concern about the chassis flex and the gear mesh. Getting the gear mesh just right will be a bit of a challenge.. but I think with the right top braces I'm hoping I will be able to keep the gear mesh from changing due to chassis flex.
Frozenpod: Interesting statement...overall isn't a shaft still more efficient? Since, it is more efficient at slower speeds?
Brian: Thank you for the calculations...I understand this car won't be as efficient as a 2 belt system...or a shaft driven car.. but I'm trying to get it to be more efficient than the E4 (three-belt system). After using your process I found that a 3-belt would have a efficiency of around 61.4% compared to a two belt, and a shaft at... 65.2%. So this set-up should yield a slightly better efficiency compared to a 3-belt system.
Valk: The Tc3 gears are the only gears I have available. Right now that bottom the shaft will be about 20mm from the top of the chassis.. I can put the esc and receiver under the shaft, but unfortunately, not the servo.
YR4dude: I do hear your concern about the chassis flex and the gear mesh. Getting the gear mesh just right will be a bit of a challenge.. but I think with the right top braces I'm hoping I will be able to keep the gear mesh from changing due to chassis flex.
Frozenpod: Interesting statement...overall isn't a shaft still more efficient? Since, it is more efficient at slower speeds?
Brian: Thank you for the calculations...I understand this car won't be as efficient as a 2 belt system...or a shaft driven car.. but I'm trying to get it to be more efficient than the E4 (three-belt system). After using your process I found that a 3-belt would have a efficiency of around 61.4% compared to a two belt, and a shaft at... 65.2%. So this set-up should yield a slightly better efficiency compared to a 3-belt system.