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Old 05-19-2007, 02:04 AM   #1321
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John, awesome job on the McAllister Nissan!
Let us know how it handles back-to-back to the other bodies you own.

That Mcallister Nissan looks a little like the Andy's nissan I own and really love.
However that Andy's nissan is no longer produced, so the Mcallister could be an alternative.
http://www.mijnalbum.nl/album=J7ZSH4G7
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Old 05-19-2007, 03:31 AM   #1322
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That really all depends on the surface your running on really...our tracks usually have too much front bite on asphault and running the Darkside Mx2 with it's extra weight toward the front makes it that much more agressive. I was able to get my bumpsteer down to very little by cutting a slot for the servo saver in the chassis which allowed me to run the servo as low as possible. So the net effect is really only a change in ackerman on mine.
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Old 05-19-2007, 11:22 AM   #1323
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Inspgagt-I cut the same slot in my chassis to run the servo saver as low as possible. I still needed half inch spacers on the steering arms. I tried 3 sizes of servo savers. It depends on what roll center you are running. Mine is fairly low to improve traction. It is nice that you have excess steering so that you can remove some to gain balance.

Mathijs-Thanks. Will do. I will have a fast motor today maybe. I see your broken axle pic. That would be the weakest point where the pin goes through it. I also notice you have the narrow left hub. How do you like the service of it having to take the wheel off. Not too much trouble I guess. I have one in my box.

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Old 05-19-2007, 01:14 PM   #1324
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Quote:
Originally Posted by John Stranahan
Mathijs-Thanks. Will do. I will have a fast motor today maybe. I see your broken axle pic. That would be the weakest point where the pin goes through it. I also notice you have the narrow left hub. How do you like the service of it having to take the wheel off. Not too much trouble I guess. I have one in my box.

John
I have a standard IRS clamping left hub for 10th pancar.
It works fine. I don't have to take the wheel of to remove the rear axle from the car.
The car in the picture of the last race is one of my friend's. He has the Asso left hub. It's a little more work, but not bothersome.
The pin is the weakest point of the axle.
On my own made axles I don't even drill the hole. I simply use CA to mount the hub.
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Old 05-19-2007, 06:07 PM   #1325
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Thanks for the axle report


Mamba Max plus Novak 3.5 R

I ran this combo today at 122F track temp. Run time was about 6.5 minutes from about 3800mA-h. 35 ampere average. Max motor temp 160F. Note that this is about 20 degrees cooler than the Mamba Max 7700 kv motor with about the same runtime. This lower temp also leads me to believe the Novak motor is considerably more efficient. Lap times were probably 1 second faster with the Novak.

Peformance was the best of all the motors I have tried with the Mamba Max in in the pan car including a Trinity N60, Novak 4.5R, Mamba 7700kv. What is better is that the motor, geared 13/96, 7.38 (slightly lower numerically than the 90/12,7.5 which I prefer), has a softer bottom end. You can use a little more throttle with the Mamba Max in the corners, which keeps it from having the irritating stalls. This softness makes the first critical 1-2 feet free of a corner exit spin. Then the low gearing comes on allowing more weight transfer to the rear as your roll on the throtte and you get better acceleration early on any straight. Finally top speed on the straight is very good, but not as good as with the 7.5 gears.
Now all is not good news. The battery got up to 154F which is a bit too hot. It had some puffiness which subsided after it cooled. This is a first for me. It looks OK but is quarantined for a day. Limit the runs to 4-5 minutes, or whatever your race is. I ran it 4 minutes geared the same and the batt was at 140 F which is OK. (Cooler is better but a least the solvent inside had not expanded into vapor at 140 F)
The brakes worked better with this motor and gearing. I was up to about 60% on a loose track. Then for some reason on the fourth pack I could no longer brake well. It could be a crash had changed something.

McAllister Nissan NPT90

I most recently ran the hotbodies Toyota GT1 body. I used it yesterday and set the car up just like I wanted in the corners. Both high and low speed corners were good. With the Nissan NPT90 cornering was also very good. The car was still very neutral so the balance is about the same with the low rearward extended wing or a high less extended spoiler. I did not have to add a spoiler. Now what is better about the body is that it has a higher polar moment of inertia on the vertical axis; it is harder to spin. This is because it is longer. This makes the car more stable in the twisty sections where you are steering left then right. Top speed was good. Stability over the bumps was good not great. I liked it. Give it a try. They are available at Stormer Hobbies or from McAllisterracing.com. Man, that metallic blue paint job sure looked good out in the sun.
There are huge vents just aft of the front fenders. These are in a much better place than the associated Nissan, but they still will probably weaken the body if used. Opening the front vents should give more steering traction.

Test tomorrow
I plan to run the 3.5 again with two packs in parallel. This should keep the packs much cooler if I limit runtime to 5 minutes. I will also stick in the 6.5 R geared with the same 96/13 and run the two packs in series.

Last edited by John Stranahan; 05-19-2007 at 11:59 PM.
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Old 05-19-2007, 10:08 PM   #1326
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Novak 6.5 R, Mamba Max, 4s1p battery
Here is a pic of the pan car with two 2s1p batterries onboard. I have wired these in series to make a 4s1p (4 in series 1 in parallel) pack. This doubles the voltage of one pack. Installed is a Novak 6.5R motor equipped with sintered rotor, geared as low as I can, at the moment, 96/13. It feels mighty strong on the bench. Passed the smoke test. Track test tomorrow.

Here is an RPM comparison

Novak Velocity 3.5R kv=10500 RPM/volt at 7.4 volts 77,700 free running RPM
Novak Velocity 6.5R kv= 6500 RPM/volt at 14.8 volts 94,720 free running RPM
Novak Velocity 7.5R kv= 5800 RPM/volt at 14.8 volts 83,520 free running RPM
If I had a 7.5 I would have tried that one first.
John
Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-novak-6.5r-4s2p-resized.jpg  

Last edited by John Stranahan; 05-19-2007 at 11:57 PM.
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Old 05-19-2007, 10:28 PM   #1327
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John, by convention of the R/C electric airplane folk (who were doing this four years ago), that battery configuration is called a 4s1p.

For a combination of cells described as XsYp,
Nominal Voltage = 3.7V * X
Capacity = cell capacity * Y
Number of cells in pack = X * Y

(see point 4 at http://www.rcgroups.com/forums/showthread.php?t=209187)
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Old 05-19-2007, 11:55 PM   #1328
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Each pack is a 2s1p. I erred. I thought they were 2s2p for some reason, part of the time. I will make corrections. Here is a pic of the back end of the McAllister Nissan NPT 90. Pretty low. You can also see the rear of the front fender cutout vents.

John
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Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-mcallister-nissan-npt90-resized.jpg  
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Old 05-20-2007, 04:39 PM   #1329
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Track about 130F

First experiment 4s1p (my two packs in series)Novak 6.5 R

Well this is what it felt like. Good punch. Great top speed, I needed brakes to enter the sweeper like the gas guys. Probably doing about 70 mph. Steered like a pig from the extra battery on board. Now the bad news. The Mamba shut the system down after only 3 laps.
I suspected a battery problem. Charged my new packs. Added some steering traction by lowering the front roll center. The car steered better. It was still fast as hell on the straights, but did not corner like it does in light trim. The Mamba shut the system down after 3 laps again. NO GOOD. Too much motor or too much Voltage. The Novak 3.5R with one battery geared at 7.5 can out accelerate this combo for about the first 1/2 of each straight.

Second experiment 2S2P (my two packs in parallel) Novak (3.5R)
Now I have done this before, but repeated it here to get temperatures. The car was fast, but still cornered slow like a heavy car. This was expected. It was able to push the slightly too tall gear, 7.38 instead of the 7.5 which makes the motor really fast. Motor Temp 185F (slightly high) Battery Temp 125F (25 degrees cooler than with one pack). So maybe a 6000mA-h pack would be the LiPo to run in the Summer for 5 minutes.

Third experiment Novak 3.5R 1 battery (geared a little too tall)
I intended to run this only 5 minutes. Instead I did not hear the timer and I ran 6 minutes. Motor was 160F. Battery was 160F as well and a bit puffy.
OK the car seemed slow after running those two other experiments especially since I am slightly overgeared. It cornered OK though. Traction was not that good, but OK in the black groove.

For the Summer it looks like I will run the Novak 4.5R with one battery and have a slightly slower car than with the 3.5R. The battery heat is now the limit with the Mamba. I have yet to run 10 clean laps in a row with the Mamba. Combined with the poor braking there seems to be other obstacles to cornering at the limit with poor traction, a pan car, and the Mamba. 18 clean laps is my norm with the GTB.

Note that I think the Mamba is making the batteries run hotter than the GTB does. That probably is a function of that huge capacitor the Novak runs as well as other internal factors.

John

Last edited by John Stranahan; 06-14-2007 at 01:26 PM.
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Old 05-21-2007, 06:38 AM   #1330
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Hi John,

this is my first post in this thread, but you can be sure that I've read nearly every single word on the last 45 pages.

We had a little race on a new builded track this weekend, maybe you are interested in some pics. There are some kind of prototype cars shown on it, one of them is half an Xray. This makes me totally freaky, as I drive an Xray in Winter-Touring and Pro10 just for fun in summertime.

Here's the link to our forum and the pics: Click. Sorry, it's not very fast, maybe Mathijs knows why...

Greetz from Germany,

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Old 05-21-2007, 09:46 AM   #1331
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flitscher, thanks for the pics. who is making that molded tub with the front brakes? does the chassis seem to be making ground effects related downforce? now i'm trying to imagine how to splice in the front breaking servo lol.
foosball - game on!
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Old 05-21-2007, 11:41 AM   #1332
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Flitshcher-Welcome aboard. What a great set of pics! Super Nice track. I see it probably has a traction treatment. Sugar water?. That front end on the front braked car is nice. I like the shock position. Beautiful machine work. Nice to see that someone else likes to use brakes once in a while. Nothing makes you feel more like you are running a fullsize car than braking hard on corner entry and then accelerating out of the turn (I autocross my Ford Focus ST also). I imagine the extra drag from rotating those drive axles and brake parts slows the car a little. I have thought about those ground effects myself as my rear pod can be tilted while keeping the same ride height. Instead I run it very low and it acts as a scoop to bring cooling air up to the motor.
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Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-bottom-rear-pod-scoop.jpg  

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Old 05-21-2007, 11:43 AM   #1333
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wow, 4 wheel braking. that has got to make the other guys mad as heck... should be a completely different class in my opinion....
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Old 05-21-2007, 11:54 AM   #1334
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The 4wheel brake car was designed by Christian Bresser and built by Peter Plumacher (multiple times german 1/10th F1 master), by hand!
The car isn't really doing that well yet. It's somewhat overweight, and the 4w brake isn't optimal yet.

The ground effect part of the car works well though.
It's a real functional addition to the car's handling.
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Old 05-21-2007, 02:04 PM   #1335
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yea, i figured the weight penalty must be a bear, but he must be able to drive that thing hard into corners.. sure is pretty.. i need to get a mill..
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