RC-Monster Forums - View Single Post - 1:8 Robitronic BR 50 Trophy Truck

othello · 07:56 AM

A new project i was working on the last few days. (Video can be found in my second post)

I bought this car off of ebay as a roller

A comparison shot beside my Robitronic Mantis truggy. Same wheelbase but smaller trackwidth

This is how the chassis looked like before i replaced it

As the BR50 uses the same chassis plate as the Mantis truggy which i already have converted to brushless i onky had to remove the front and rear axles.

I then removed the truggy axles from the truggy chassis plate and replaced them with the BR50 axles. I'm still using a Neu 1515/2Y (1100kv) motor, Kontronik Jazz 55 ESC and 9s1p A123 batteries to power my 1:8 conversions.

5s1p pack at the rear, receiver and BEC box beside the centerdiff and servo with Eagletree logger on top of it at the front of the car

The other side shows the front mounted Neu 1515 motor and the other A123 pack in 4s1p configuration at the rear. The ESc is ziptied between motor and servo on a separate plate which is mounted between front axle and center diff

Switching back to my truggy configuration is easely done. It's just a matter of switching axles and using a smaller pinion. And using another body of course.

As the BR50 trophy truck uses smaller Buggy tires gearing had to be adapted to get similar speed compared to the Mantis truggy. The BR50 axles use the same bevel and ring gears (10:42) when compared to the truggy axles. I use a 46t kyosho plastic spur. I used to run my truggy with a 14 or 15t pinion. I chose a 18t pinion. Overall reduction: 1:10,73. With 9s A123 cells the 1100kv motor should rev around 30000rpm max under load (9s x 3V x 1100kv). Which leads to a calculated top speed of 37-38mph (around 60km/h). A good starting point for this car as i never had temperature issues at this speed level when i run my truggy (heavier wheels) and the nitro version was clocked at 32mph or 35mph depending which reviews you read: rccaraction or rccardriver.

Ready to roll the BR50 wheighs 10.1lbs / 4.6Kg. The body alone wheighs 1.1lbs / 500gr. Batteries wheigh 1.5lbs / 706gr.

On its first maiden a few gas stabs on asphalt showed that top speed was right were i expected it to be. No need for a smaller or bigger pinion from a speed point of view. Eventhough my typical RC spot was completely soaked, wet and muddy (snow had almost melted) i chose to give it a run. Everything went fine aside from 2 tires which came partly unglued.

Well this how the BR50 looked like after its first run

Well atleast the pinion remained uncovered with mud ;-)

	(#1)
othello HV basher Offline Posts: 392 Join Date: Jun 2007 Location: Austria (Europe)	1:8 Robitronic BR 50 Trophy Truck - Brushless - 01.30.2009, 07:25 AM A new project i was working on the last few days. (Video can be found in my second post) I bought this car off of ebay as a roller A comparison shot beside my Robitronic Mantis truggy. Same wheelbase but smaller trackwidth This is how the chassis looked like before i replaced it As the BR50 uses the same chassis plate as the Mantis truggy which i already have converted to brushless i onky had to remove the front and rear axles. I then removed the truggy axles from the truggy chassis plate and replaced them with the BR50 axles. I'm still using a Neu 1515/2Y (1100kv) motor, Kontronik Jazz 55 ESC and 9s1p A123 batteries to power my 1:8 conversions. 5s1p pack at the rear, receiver and BEC box beside the centerdiff and servo with Eagletree logger on top of it at the front of the car The other side shows the front mounted Neu 1515 motor and the other A123 pack in 4s1p configuration at the rear. The ESc is ziptied between motor and servo on a separate plate which is mounted between front axle and center diff Switching back to my truggy configuration is easely done. It's just a matter of switching axles and using a smaller pinion. And using another body of course. As the BR50 trophy truck uses smaller Buggy tires gearing had to be adapted to get similar speed compared to the Mantis truggy. The BR50 axles use the same bevel and ring gears (10:42) when compared to the truggy axles. I use a 46t kyosho plastic spur. I used to run my truggy with a 14 or 15t pinion. I chose a 18t pinion. Overall reduction: 1:10,73. With 9s A123 cells the 1100kv motor should rev around 30000rpm max under load (9s x 3V x 1100kv). Which leads to a calculated top speed of 37-38mph (around 60km/h). A good starting point for this car as i never had temperature issues at this speed level when i run my truggy (heavier wheels) and the nitro version was clocked at 32mph or 35mph depending which reviews you read: rccaraction or rccardriver. Ready to roll the BR50 wheighs 10.1lbs / 4.6Kg. The body alone wheighs 1.1lbs / 500gr. Batteries wheigh 1.5lbs / 706gr. On its first maiden a few gas stabs on asphalt showed that top speed was right were i expected it to be. No need for a smaller or bigger pinion from a speed point of view. Eventhough my typical RC spot was completely soaked, wet and muddy (snow had almost melted) i chose to give it a run. Everything went fine aside from 2 tires which came partly unglued. Well this how the BR50 looked like after its first run Well atleast the pinion remained uncovered with mud ;-) Brushless 1:5 custom 4wd Baja based on 1:8 truggy chassie Jazz 55-10-32, Neu 1515/2Y (1100kv), 9s2p A123 (27v), up to 3.1KW Latest video with eagletree Data inserts: Run on asphalt Last edited by othello; 01.30.2009 at 07:56 AM.