Ofna DM-One Brushless Conversion (DM-1)

I have yet to hear of anyone running a 2-speed brushless on the DM-1. When I was building my Super RS4 (EP) I heard a few people talking about using the 2-speed from the Nitro version. What I gathered was that there was little need since the electric motor has a flat torque curve and would not benefit much from the 2-speed. I do not know personally but will be interesting to hear how yours works out with the 2-speed.

If you have the room I would think a 2-speed on a larger 1/7th scale would be fun. How do these things shift? Do they use some type of centrifugal clutch mechanism that switches out at a certain RPM?

[_paralyzed_]

Originally Posted by dangerwr

I have yet to hear of anyone running a 2-speed brushless on the DM-1. When I was building my Super RS4 (EP) I heard a few people talking about using the 2-speed from the Nitro version. What I gathered was that there was little need since the electric motor has a flat torque curve and would not benefit much from the 2-speed. I do not know personally but will be interesting to hear how yours works out with the 2-speed.

If you have the room I would think a 2-speed on a larger 1/7th scale would be fun. How do these things shift? Do they use some type of centrifugal clutch mechanism that switches out at a certain RPM?

exactly, a centrifugal clutch and a one way bearing. when the second speed hits and overrides the first, the first just spins freely because of the one way

[year1camaro]

Originally Posted by dangerwr

I have yet to hear of anyone running a 2-speed brushless on the DM-1. When I was building my Super RS4 (EP) I heard a few people talking about using the 2-speed from the Nitro version. What I gathered was that there was little need since the electric motor has a flat torque curve and would not benefit much from the 2-speed. I do not know personally but will be interesting to hear how yours works out with the 2-speed.

If you have the room I would think a 2-speed on a larger 1/7th scale would be fun. How do these things shift? Do they use some type of centrifugal clutch mechanism that switches out at a certain RPM?

The dude who started this post was using a 2 speed, but he din't reply as of yet. One certain benefit would be torque curve, if you could keep it hooked up.

[jhautz]

Still running the 2 speed in mine. Works great. RCMonster even makes a 2 speed pinion adapter now so you dont have to make your own like I did back then.

RCmonster Mike built an InfernoGT last fall and used the 2 speed also.


EDIT: In post number 85 in this thread there is a short video of the car running and you can hear it shift. The pitch of the motor and gears changes when it shifts. Its like a little turbo boost kicking in.

Here we have my latest creation. I am using the solid spool with the center shaft and out drives from the 2-speed. Also, I started with a Novak conversion kit but am abandoning this idea for a RCPD top plate and motor mount with a RC-Monster battery tray.

My current plan is to use a MMM v3 and a Neu 1512 1.5D/F. I think I will gear this 3300Kv motor at 14/51 on 4S to start and see how things go. Hopefully they go fast!

Oh well, it will be several weeks for the RCPD stuff to get here so this will be it for a little while. I might anodize the parts red if I can piggy-back an order from work. Cheers!

[BL_RV0]

Originally Posted by dangerwr

Here we have my latest creation. I am using the solid spool with the center shaft and out drives from the 2-speed. Also, I started with a Novak conversion kit but am abandoning this idea for a RCPD top plate and motor mount with a RC-Monster battery tray.

My current plan is to use a MMM v3 and a Neu 1512 1.5D/F. I think I will gear this 3300Kv motor at 14/51 on 4S to start and see how things go. Hopefully they go fast!

Oh well, it will be several weeks for the RCPD stuff to get here so this will be it for a little while. I might anodize the parts red if I can piggy-back an order from work. Cheers!

Nice start man! Keep the pics coming.

[ssspconcepts]

Brushless OFNA DM-1 SPEC: Flightpower 5S 5000mah (25C) Battery, Mamba Monster Speed Controller, Neu/Castle 1515 2200kv motor, 51T Mod1 Spur gear, 25T Mod1 pinion (I know this is too big...but its fast as heck and fun), and Spider Eight 43/13 ring and pinion differentials.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 51
Pinion Tooth Count: 25
Total Voltage: 18.5
Motor KV: 2200
Tire Diameter (inches): 4.17
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0.006
Spur/Pinion Ratio: 2.04 : 1
Total Ratio: 6.74769 : 1
Tire Circumference (inches): 13.1 inches (332.75 mm)
Total Motor Speed: 40700 RPM
Vehicle Speed: 74.83 mph (120.2 km/h)
Effective KV Value: 2200
KT constant: 0.61 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...

As promised here is my amature video...

[ssspconcepts]

Here are the latest pics with the one speed direct drive installed.

From DM-1 Spec

From DM-1 Spec

[year1camaro]

[QUOTE=ssspconcepts;253388]Brushless OFNA DM-1 SPEC: Flightpower 5S 5000mah (25C) Battery, Mamba Monster Speed Controller, Neu/Castle 1515 2200kv motor, 51T Mod1 Spur gear, 25T Mod1 pinion (I know this is too big...but its fast as heck and fun), and Spider Eight 43/13 ring and pinion differentials.

Differential Ratio: 3.3076923076923075
Transmission Ratio: 1
Other Ratio: 1
Spur Tooth Count: 51
Pinion Tooth Count: 25
Total Voltage: 18.5
Motor KV: 2200
Tire Diameter (inches): 4.17
Tire Ballooning (inches): 0
Motor Current Draw: 0
Motor coil Ω: 0.006
Spur/Pinion Ratio: 2.04 : 1
Total Ratio: 6.74769 : 1
Tire Circumference (inches): 13.1 inches (332.75 mm)
Total Motor Speed: 40700 RPM
Vehicle Speed: 74.83 mph (120.2 km/h)
Effective KV Value: 2200
KT constant: 0.61 oz-in/A
Motor Torque: Amperage not specified...
Final Torque: Amperage not specified...
Final Power: Amperage not specified...

As promised here is my amature video...

What tires did you use for this run? Car looks fast fast fast!!! nice...Now to get it to stick to the road might be a challenge with all that power.

[year1camaro]

Originally Posted by jhautz

Still running the 2 speed in mine. Works great. RCMonster even makes a 2 speed pinion adapter now so you dont have to make your own like I did back then.

RCmonster Mike built an InfernoGT last fall and used the 2 speed also.


EDIT: In post number 85 in this thread there is a short video of the car running and you can hear it shift. The pitch of the motor and gears changes when it shifts. Its like a little turbo boost kicking in.

I made my pinion adapter also. I probably would not have bought it even if I knew about it.....I'm into the fabrication end of this hobby. I also made the top plate and motor mount. It's cool to hear your not having problems with the 2 speed,,, that was a concern when I started this project. I watched your video, very nice...looks like it works great!

Man that thing is fast--looks very powerful on the 5S. Do you think it is capable of going 70mph with your current setup? I can not wait to finish mine up!

[ssspconcepts]

Originally Posted by dangerwr

Man that thing is fast--looks very powerful on the 5S. Do you think it is capable of going 70mph with your current setup? I can not wait to finish mine up!

The calculations say it is possible to go 70+mph...but I never could get it up to full throttle because the tires constantly break loose. Towards the end of the video there were a couple of passes where I was close to full throttle but not quite. I absolutely have to get a radar gun. I keep talking about it but I keep spending my $$$ on car parts!

By the way...I see some other folks on here are installing one-speed centers. This was a PITA to keep the DM-1 center shaft from sliding back and forth because there aren't any bearing stops milled into the shaft. Brian helped me come up with the idea to make a shim using 8.1mm inner diameter stainless steel tubing and a couple of 8.1mm innerdiameter washers. It worked like a charm. I still have some of that tubing if anybody needs it. If you order it from onlinemetals.com they charge an arm and a leg for shipping.

Originally Posted by ssspconcepts

The calculations say it is possible to go 70+mph...but I never could get it up to full throttle because the tires constantly break loose. Towards the end of the video there were a couple of passes where I was close to full throttle but not quite. I absolutely have to get a radar gun. I keep talking about it but I keep spending my $$$ on car parts!

By the way...I see some other folks on here are installing one-speed centers. This was a PITA to keep the DM-1 center shaft from sliding back and forth because there aren't any bearing stops milled into the shaft. Brian helped me come up with the idea to make a shim using 8.1mm inner diameter stainless steel tubing and a couple of 8.1mm innerdiameter washers. It worked like a charm. I still have some of that tubing if anybody needs it. If you order it from onlinemetals.com they charge an arm and a leg for shipping.

I bought one of those Hotwheels radar guns off eBay for $20 and works pretty good! I am going to gear mine around 60mph at first and see where the temps are with my driving style.

Now, on the solid center spool I wound up using the center shaft and outdrives from the 2-speed that came with the car and not the little kit. Did you do the same or did you do something different?

[ssspconcepts]

Originally Posted by dangerwr

I bought one of those Hotwheels radar guns off eBay for $20 and works pretty good! I am going to gear mine around 60mph at first and see where the temps are with my driving style.

Now, on the solid center spool I wound up using the center shaft and outdrives from the 2-speed that came with the car and not the little kit. Did you do the same or did you do something different?

Yep...had to use the 8mm DM-1 Spec center shaft...that's why you will need the 8.1mm inner diameter steel tubing.

[SpeedAssault]

Originally Posted by ssspconcepts

The calculations say it is possible to go 70+mph...but I never could get it up to full throttle because the tires constantly break loose. Towards the end of the video there were a couple of passes where I was close to full throttle but not quite. I absolutely have to get a radar gun. I keep talking about it but I keep spending my $$$ on car parts!

By the way...I see some other folks on here are installing one-speed centers. This was a PITA to keep the DM-1 center shaft from sliding back and forth because there aren't any bearing stops milled into the shaft. Brian helped me come up with the idea to make a shim using 8.1mm inner diameter stainless steel tubing and a couple of 8.1mm innerdiameter washers. It worked like a charm. I still have some of that tubing if anybody needs it. If you order it from onlinemetals.com they charge an arm and a leg for shipping.

Hey That is a beautiful car Great pics, enjoyed reading

I am blown away that with a ratio of 6.7, a 51spur and 25 pinion that you still have a hard time doing full throttle.!and end up torque fliping
maybe you could move the motor forward ...
whats the weight?

The video was cool,looks like you need a circle track. definitely shows the power and speed, amazed to see it flip
Looks like I'm going to mount my motor in front

Thank you for posting video , I was going to run a 10:1 ratio but going to change to 5 or 6:1. although it's 9lbs and 21" wheels base X 15" wide so there shouldnt be any torque flippin
wish you were closer so we could race, when mine gets done that is


still working on it, needs a motor mount and tire adapters for the 1/5 but also make it easy to put on 3.2 wheels for the offroad stuff

again great build thread
Sweet ride, cant wait to see a new body on it, keep it coming