Pinions and Spurs

Test 1 – Basic

Test 2 – Anti-vibration camera setup

My first real FPV video I did a while back, miss the old tc5r chassis

I am currently working on fine tuning the Tamiya TA05 chassis to prepare for racing in the 17.5 class at the www.rctrack.com The Track in Gaithersburg MD.

Currently the following are the specs for the car

1. LRP SXX TC Speed Control, Power Profile 8
2. Speed Passion 17.5 Brushless Motor
3. 48p 78/38 Spur and Pinion
4. Optional Tamiya drive belts
5. Integy drive shafts
6. HPI tires (Pro Compound)
7. Ferrari F430 Body
8. Spektrum RX/TX
9. Trakpower 4900 mah 25C lipo
10. TRF shocks and TC5 17lbs springs

The car so far handles really well on asphalt track in gaithursburg md, my fastest laptime on the track is 16.5 seconds. The average for most drivers seems to be around 17-20 seconds, I intend to further tune the car and post results if I am able to further reduce lap times

So finally got around to building my next rc car. This time around I was looking for a good RTR chassis that was 4wd and economically priced. The HPI Sprint 2 seems to have fit the bill for being under 200.00 for a complete RTR package. I did however replace the radio equipment and used my spektrum dx3r system, everything else is bone stock.

The car handles well with it’s stock x-pattern d compund tires, I would guestimate the top speed to be around  20-25mph with the 15t firebolt brushed motor. The steering seems a little loose and I would suspect that the chassis would probably not handle a faster motor than a 5700kv type without upgrading some key components.

I plan to do a video on performance of the stock setup followed by a brushless conversion and then another look at how the chassis handles more power.

Also note that since this is brushed, the power is not used efficiently so run-times are low.. around 5 minutes or so.

Took the Ta05 speed passion 2.5R combo for a run as well, nothing changed on the car setup except for rear wing addition and FPV video gear. The car ran very well, as expected the added weight of the FPV gear made the car a little unstable at high speeds nearing 50mph. 

I have radar tested this setup for 50mph in windy conditions along with rear wing, I would say it was pretty near that target given that it was not windy that day. 

The video is more fuzzy on this car, I beleive this is mainly due to the car being setup lighter than the TC5R and so on corners and little bumps the car shakes more and thus causes more video disturbance..

I will hopefully be working on some kind of universal chassis of some kind that can hold the FPV gear better and definitly upgrading to 5.8ghz system when I can.

So finally got around to test out the new motor/gear/25c lipo setup on the TC5r. It was an extremely hot day, average ambient temperature was about 90-96. The car performed well, but ended up blowing the left rear tire and crashing as a result

The Mamba Max 5700 combo 87/22 gearing with Trakpower 3s 4900 25c combo is very very good, I enjoyed running the car. However the FPV equipment it self is pretty heavy along with the 3s lipo made the car somewhat unstable at high speeds, I estimate the car was topping out at around 60mph I did not get a chance to use the radar gun to make sure but given the setup and my calculations it should be doing at least that much.

I intend to get an OSD setup soon and perhaps in time upgrade to a 5.8ghz video system so I get better reception, the whole project has been challening because there are a lot of moving parts. The video gear and the car the electrics all need to be setup well and mounted on the car so they dont make the vehicle unstable.

I think I’ll be doing this in phases, next one will definitly be the OSD so we can start seeing some data like motor temperature, RPM and of course GPS based speed.

My digital camera seems to have come back from the dead some how, so thought I would write a post on what I have been up to. 

I am currently working on selecting the best motor/esc/lipo setup for fastest 3s lipo race able car, so far I have tried the good old Novak 3.5R, the Mamba 7700kv and Traxxas 3500kv motor. 

All three motors were run on the TC5R  chassis using the VXL3S speed control, they all survived the 11.1v of power mostly because they probably were never able to exceed their rpm limits and perhaps with a lot of luck as well.

The problem is that the lower turn motors like the speed passion 2.5R run very very fast on 2s but seem to max out at or around 60mph. That is plenty fast for racing, but I just have the itch to see if we can go faster, maybe around 70-80 clean on top speed and still be reasonably racable.

The TC5R with the above motors sits pretty heavy and I have had to use harder roll-bars so it does not hit the ground everytime I make a fast corner. The over all stability seems better due  to added weight but I still need a solid motor/gear combo that can give me over 60mph and be able to go around a large track without too many issues.

My plan was to order the Mamba Max 5700 system which I have installed and done some inital testing, everything looks good just hope the weather is clear this weekend so I can do some good test. Also this time around I plan to be in FPV mode, essentially a wireless camera mounted on the car so I can get a feel of the car and power as if I was actually sitting in it.

Since my Novak GTB 3.5 has blown up most likely due to gearing issues, I decided to upgrade the TA05 and TC5R to break my current 53mph record with Novak GTB and TC5R combination setup. So the first test was to run the TA05,  it was a very windy day and I was also experimenting with HPI X-pattern wheel/tires on both cars so was not able to get my target 60mph top speed. 

According to my calculations tha TA05 should have hit approximately 60mph, however clocked a clean 50mph (previous top speed 43mph) run using a Speed Passion 2.5R motor. This is a fantastic motor, not only does it have plenty of torque (using Trakpower 2S 5400mah 16c lipo) but an outstanding 13800 rpm/volt and it sounds awsome.  I think if it was not as windy and I was not using the rear wing, I reckon I should have hit close to 60 but that will have to wait since I am waiting to receive a Trakpower 2s 4900 25C lipo pack.

The 4900mah 25C rating should give me 4.9 x 25 = 122.5 amps, currently with the 5400mah 16c I am getting 5.4 x 16 = 86.4 amps. The Mamba Max ESC is rated 100amps max so with the 4900 25c pack I should definitly get more torque and hopefully my target 60mph top speed.

In all I am very happy with the overall performance, the motor is very light and the TA05 with everything weighs only 1472grams. I think once I get the 25c rated lipo, I will do another speed run to try for 60mph again, hopefully it’s not too windy again.

The TC5R I decided to turn to a traxxas VXL 3S system that I had bought a while back, but never really used it much. The reason behind using this system was essentially research on the internet and realizing that I will need much more torque i.e. battery power to hit traget speeds of 70-80mph. And boy does this thing have some serious power, the motor is 3500kv and I am running 48p 75/35, since this is a low kv motor I am able to use trakpower 3s 5400 16c lipo.The car is definitly heavier but that is increasing general stability and straight running, the torque on this thing is so nice the car continous to wheel spin even when reaching higher speeds. The problem however during this run is that I was unable to do enough runs to actually clock the speed by my bushnell radar gun. 

In only a two test runs I lost traction big time and the car flew about 4-5 feet in the air after hitting the grass. Fortunately there was no major damage, I lost the right rear suspension holder and the spur gear (kimborough spur) seems to have disintegrated, not sure if this was caused due to heat or simply got crushed due to too much power.

This is my first test of an FPV equipped car, the vehicle is Team Associated TC5R with Novak GTB 3.5R brushless system. I am using the 900mhz video system from hobby wireless. This is just a first test, I am currently working on a new enzo body and other upgrades and will be making a new video.

This is what the car looked like when the video was shot, but I think there can be some updates made to the body to decrease wind resistance among other things, will be posting a video and pictures soon.

This is the first speed run test with basic gearing 48p 87 spur and 17 pinion, novak GTB 3.5 and was able to hit 53 mph max in a straight line.