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Old 02-12-2013, 08:41 PM   #181
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Originally Posted by dickyng View Post
has the Awesomatix A700EXL logger
If you are asking if there is a model for the Awesomatix I currently do not have one. I know a few guys were going to try and create one but I haven't seen anything yet. It would be tricky because the awesomatix uses a completely different suspension and shock geometry but could be done.
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Old 02-12-2013, 08:54 PM   #182
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Originally Posted by speed6 View Post
Thanks for the above, so re: point number 3 if for eg entry off power is marked as very loose and car still understeer does it mean that tires are not doing their job well?
The bar graphs are indicators of the handling tendency based purely on weight transfer. That way as you change suspension, springs, shock angle you can see the load on the tire change and the bars graphs provide a graphic indicator of how much of a change that is as wellas showing which direction you are moving the handling, towards understeer or oversteer. There is no tire math model for RC cars available so tires effects of relating to track surface, rubber compound, tire load, slip angle, camber and so on are not accounted for.
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Old 02-13-2013, 03:00 AM   #183
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Bob, was the brushless motor sensor not reliable? Just curious as I've been throwing around the idea of picking up an Eagle Tree system myself.
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Old 02-13-2013, 05:18 AM   #184
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Yeah the guys who tried this for dyno testing found the Eagletree brushless sensor to be totally useless.

I've been running a Novak Sentry in my TC for the past couple of seasons, this does work very well (I'm also now using it as part of a dyno).

Regarding G-forces in TC racing, I usually see just over 3G lateral round the sweeper at the end of the straight (with some spikes of almost 4G at the start when the tyres are hot and sticky).
I wanted the eagletree because of the 50 hz sample rate. I just bought it back in January and have been struggling getting EagleTree to fix problems with their logging software. These issues may have had something to do with the problems you had. They seem to pay lots of attention to the airplane guys and not so much to the car guys.

The first problem was with the logging software not saving the g sensor data to the data file. They have fixed that. Now I am trying to get them to correct the problems with the RPM to Speed calibration. There are a couple issues there that will produce totally incorrect motor RPM and speed readings depending on where you have the sensor mounted. I have told them about the problem and how to fix it so we will see. I have a work around solution that produces correct motor RPM and speed values if anyone has run into this problem.
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Old 02-13-2013, 05:28 AM   #185
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Bob, was the brushless motor sensor not reliable? Just curious as I've been throwing around the idea of picking up an Eagle Tree system myself.
I wouldn't recommend the Brushless RPM sensor. It seems to work OK sitting on my desk at constant RPM but put it on the track and the output I get has so many spikes and drop outs I can't make any sense of it.

For RPM measurement I would suggest the Optical Sensor as it is the easiest to install. Just need to paint 1/2 of something white. The magnetic sensor works well too. It can just be a little tricky to mount the magnets.
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Old 02-13-2013, 09:57 AM   #186
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I use Kimbrough spurs on my cars and the magnets fit perfectly in the holes. If you're afraid they'll fall out a little dab of Shoo Goo will do. To get motor RPM you'll have to do a little math with the gear ratio of course.
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Old 02-16-2013, 07:24 PM   #187
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Promised some test results so here is one lap recorded in a GT2 race. Our GT2class is tub chassis and 21.5 motors. I expect some significant increases in g level when I switch the data logger to the 417 with 13.5. I have broken the track into sections to hopefully show what is going on throughout the lap.
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File Type: pdf GT2Lap_Small.pdf (152.9 KB, 125 views)
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Old 02-17-2013, 02:59 PM   #188
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Just uploaded the TC6.1 Worlds Model with Keven Hebert's US Indoor Champ setup.

The TC4 model has also been updated.
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Old 02-18-2013, 03:05 AM   #189
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Promised some test results so here is one lap recorded in a GT2 race. Our GT2class is tub chassis and 21.5 motors. I expect some significant increases in g level when I switch the data logger to the 417 with 13.5. I have broken the track into sections to hopefully show what is going on throughout the lap.
Awesome stuff Bob!
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Old 02-18-2013, 08:14 AM   #190
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Thanks for posting the data Bob, I have been curious to see what you logged.

I appreciate how you presented it with the 3 graphs in line with each other and the vertical lines and track section labeling make it really easy to read. Any chance you have motor amp draw for the 21.5 motor you could post up inline with rpm data? Curious to see how many amps you were drawing under acceleration.

By looking at your data I would guess if you would dyno your motor and try different timing settings you would want to focus on the 6,000 - 10,000 rpm average range. Assuming your gearing was ideal for your track that day. What do you think the RPM range is you would focus on for comparing dyno results?
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Old 02-18-2013, 11:32 AM   #191
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Here is the same lap with motor current. Max current 18 amps.

Our GT2 class is fixed gearing (FDR 4.0 min), and no timing so don't really think about tuning the RPM range just get as close to the min FDR as possible. If we could change gearing and timing and I had some good dyno data at different timing I would take a much closer look. I have used RC Crew Chief to simulate acceleration with a generic 21.5 motor and it shows the best time to distance numbers are achieved using the lowest FDR we permit.

Part of the reason for the Eagletree is to build a flywheel dyno. Just working out some concepts ideas right now. Actually thinking about a gear reduction to keep the flywheel RPM lower. Means a heavier flywheel is required but it may be worth it to allow testing of a wider range of motors.
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File Type: pdf GT2 Lap Current.pdf (143.2 KB, 139 views)
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Old 02-18-2013, 12:46 PM   #192
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Here is the same lap with motor current. Max current 18 amps.

Our GT2 class is fixed gearing (FDR 4.0 min), and no timing so don't really think about tuning the RPM range just get as close to the min FDR as possible. If we could change gearing and timing and I had some good dyno data at different timing I would take a much closer look. I have used RC Crew Chief to simulate acceleration with a generic 21.5 motor and it shows the best time to distance numbers are achieved using the lowest FDR we permit.

Part of the reason for the Eagletree is to build a flywheel dyno. Just working out some concepts ideas right now. Actually thinking about a gear reduction to keep the flywheel RPM lower. Means a heavier flywheel is required but it may be worth it to allow testing of a wider range of motors.
I contacted John Stranahan (The guy with the huge Dyno thread) a while back and he advised me to stay away from the Eagletree and go with the Novak Sentry since the Eagletree suffers from data spikes which renders the data useless for dyno purposes.

I don't know if you have seen this thread before:
Dyno, Homemade, Using a Novak Sentry Data Logger, Continued, The Experimental Thread.
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Old 02-18-2013, 01:38 PM   #193
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Thanks for that Serpenteer. I had some communication with John as well.

I have experienced the spikes first hand. That's why I have been testing with three different RPM sensors - Brushless Motor, magnetic and optical. The magnetic and optical provide very similar results. Not sure which one I was using in the graphs that are posted above. I definitely won't be using the Brushless Motor sensor though.

The advantage the Eagletree has over the Sentry is the sample rate. The Novak sample rate was 10 Hz (samples per second) and the eagle tree is 50 Hz. Thats 5 times faster. I want as many data points as I can get and the Eagletree should hopefully provide that.
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Old 02-27-2013, 03:38 PM   #194
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Graphs of a lap in my 417 below. Unfortunately the track layout changed so I can't do a corner to corner comparsion but 180 degree sweeper is still there.

I was expecting a bigger difference in the maximum lateral g. When I thought about it though both cars are TC's running the same tires, one is about 100gms heavier and 10 years older but still similar cars. The 417 is slightly better at around 2.4g in the sweeper versus 2.2 for the TC4.

Anyways thought some of you might find it interesting.

Will have a TOP Photo EX model when I update the website later this week. Also have a AE RC8T to measure up.
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Old 02-28-2013, 06:06 AM   #195
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Duhhh!! Forgot to upload the graphs
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File Type: pdf GT1Lap_Small.pdf (152.5 KB, 87 views)
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