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Old 05-16-2007, 06:28 PM   #1291
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Good luck Drew

Mathijs-Thanks for the pics. Now what's with the heineken sticker, Sponsor war.


Front Suspension Report (Finished)
I borrowed pieces from prototype one until I got the same performance on Protoype 3. It turns out, I needed all most all the pieces from one which worked equally well when bolted to the new suspension blocks. So here are some critical dimensions. Upper inner pivot center is 1.18 inch above the chassis top. Lower pivot is as low as possible without rubbing the A-arm hinge bosses on the chassis. The lower arm is a modified associated upper arm, it has a glued in place .750 extension (#8 aluminum stud in the middle) which makes it .550 inches longer than the upper arm pivot to pivot. Kingpins are 1.350" long Titanium Nitride coated pins. Upper outer arm pivot is as high in the wheel as possible. Pivot balls are hardcoated aluminum IRS pieces. These hard coated balls seem to be essential for the maintaining the great performance with use.

I'm leaning toward Inspector Gadgets view that some of the magic, responsible for good performance, must be the camber curve that is created with these two arms. If I roll the car on the bench by pushing one side down front and back I find the camber changes not at all. It keeps the tread completely at the same angle during travel. There is also no sideways scrub. Some of the rest must be the suspension hinge at the kingpin and very direct shock action.

On the first pack today I got much better results than my previous photo. The last bit of robbing I did was the upper inner suspesion mount is now a 0 degree instead of a 5 degree. This lowered the upper pivot about .025 inch. I also eliminated the mini shock towers. I got my good tire wear pattern. I added a 1/32 spacer under the steering arm to move the outer lower A-arm down. Steering was as perfect as I could want. Ok my work is done. No more front suspension reports. Caster is at 4 degrees camber, inside the sweeper tire is at -1.5 degree, camber outside the sweeper tire is -2 degree.

A couple of things could be improved on a new build. The lower A-arm shim blocks could have both vertical screws moved forward to provide more steering link clearance. The shim block could then be tapered down in the back. The upper cantilevered Aluminum suspension arm could be made a little wider for strength and moved outward to eliminate the stacked washers between the upper A-arm and the shim block. I will replace these washer with a plastic spacer as soon as it comes in. I also have pieces now to build two great performing front suspension that differ only in the suspension block used.

John
Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-front-suspension-prototype-3-008-resized.jpg  

Last edited by John Stranahan; 05-17-2007 at 10:20 AM.
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Old 05-17-2007, 04:03 AM   #1292
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My friends were just messing with me with that Heineken sticker.
I just hope my sponsor doesn't find out!

John, how does the lower shock mount hold? It looks a little vulnerable!
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Old 05-17-2007, 06:25 AM   #1293
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John, I believe at one time you mentioned running a higher voltage/ lower motor KV combo. Now that you've got the Mamba Max all you need is a different motor and battery. Might I suggest a Novak 7.5 or 8.5 and a 4s Maxamps lipo. The Mamba will take 4s( it's been done many times by the monster truck crowd). The current draw should drop to just over half what it is now. You could also use a smaller-less mah- battery. Gearing would also go higher and last longer. Don
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Old 05-17-2007, 09:01 AM   #1294
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Don-I was thinking of that just yesterday. I plan to test the 7700 Mamba motor first, then maybe I'll try the Novak 6.5R that I have in hand with higher voltage. I suspect that low gears may still be neccesary.

Mathijs-That lower shock mount seems to be holding up fine. The ballstud is long and sticks out the other side. It is well protected being inside the wheel. I have yet found the need to replace that long ball stud or the outer arm end because of crash damage. The suspension is about as rugged as the stock suspension with this suspension block. With the non adjustable suspension block it is actually more rugged than stock due to the free hanging lower plastic suspension mount. This gives the lower arm more cushion in a crash.

John

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Old 05-17-2007, 03:19 PM   #1295
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Quote:
Originally Posted by adamge
Man, that doesn't help me at all. Nothing in the picture is purple! Check your monitor settings ;>

There are four red chargers and one dark blue charger. There are two silver power supplies. There are four silver lipo balancers and four big black lipo packs. There is one black Sharpie marker, and one Micro Deans charge cable. The only thing remaining is the left rear speaker for my 5.1 home theatre system. It's not involved in the charging process - it just needed a place to sit.
then what is the Blue charger doing between the 4 red chargers and the 2 silver power supplies that we thought were black purple and white... but the numbers are the same with just different colors which shouldnt affect the outcome of the speaker volume of the pen that changed the color levels of the photo...
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Old 05-17-2007, 04:15 PM   #1296
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Track Report
Track temp 128F (cold front came in yesterday). Motor 150F after a 10 minute run.

The Mamba worked just OK today. I ran two packs and had some trouble on the straight. Once the car came to a skidding stop (spin out) coming out of the gentle turn before the straight. On the second pack it did the same thing in the middle of the straight (this time at about 50 mph, I was lucky there was no crash). The gear lash was on the high side of normal for me. I reduced it and the next pack I went 10 minutes without trouble. Brakes were smoother, but not smooth. I can't get into a nice braking Rhythm like I used to on my two hairpins. Sometimes it works well other time it make a very sudden spin just before corner entry and ends up nose to the flapper board.

I ran new tires today. I compensated for the ride height in the front with the shock collars and raised the inner lower A-arm pivots .010 inches to reduce some steering. Steering was good now. Speed on the straight was outstanding with the better traction from the large rear tire.

I have a note out to Robinson Racing to make a Titanium Nitride Gold hardened steel pinion in 12 Teeth again. I'll tell you if I have any luck.

John

Last edited by John Stranahan; 05-17-2007 at 09:11 PM.
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Old 05-17-2007, 09:04 PM   #1297
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Mamaba Max 7700 Kv Motor
Some of the new toys have arrived. This includes the Mamba Max 7700 Kv motor that was recomended to remove irregularities in the speed control operation. Some problems. The Mamba thread, on RCtech, currently recommends to hardwire the motor, although the manual reccomends plugs and never to shorten the motor wires. I thought that was a strange instruction, but am happy it has been superceeded. I tried to remove the back cover of the motor to see if I could solder the 14 gauge leads inside the case. There are no external solder tabs. The motor has overly large 12 gauge leads for a pan car. No luck. I removed the screws with some heat but the plate seems to be at least slightly glued in place by the thread lock. I could not pry or unthread the back with simple tools. Same for the front. I decided to remove the wires at the speed control. I did not want to do this because the solder used had wicked up the wires and made the wires very stiff. I thought the solder might be some higher temperature stuff than I use. It was hard to unsolder. The new wires were easy to solder in place with Deans Ultra Solder and a very high temperature tip (1000F). The speed control passed the smoke test on the bench. That sticker under the leads is a bit toasty looking, though.

The motor seems to be of the same stackless design as the Trinity motor which I photographed the guts of previously. You can tell this by just spinning the arm. There is no resistance or cogging felt at all. This probably means there is no iron nor slots inside, just wire.

First test on the den floor. The car still starts backwards a lot and then corrects itself. There are agonizing pauses before rotation starts sometimes in the hand. Well I can't say that I am shocked. I'll test it on the track tomorrow, maybe it will be better there. I am gearing the 1/10 scale pan car 87/16 to start with. This is a little lower ratio than I would calculate using Kv's and my present gearing. I expect the stackless design to need some help with fairly low gearing.

Hitec Titanium Gear Servo.
Also in is a new Titanium gear Servo from Hitec. Model number in the Pic. I'll give a report later. This servo is just a bit narrower than the one I was using but it fit the same Associated mounts due to their lateral adjustment ability. I did not have to drill new holes.

John
Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-mamba-max-7700-kv-002-resized.jpg   Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-hitec-titanium-gear-servo-resized.jpg  
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Old 05-17-2007, 11:36 PM   #1298
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Nissan GTP ZX (NPT 90 GTP)

The first pic is a fullsize Nissan GTP ZX. The pic was stolen from here where there are more pics http://www.a2zracer.com/page92.html
There is a good You tube video of the fullsize car racing with some commentary from the current owner of one of the cars.

http://www.youtube.com/watch?v=_M2ibevE5PU

I received the McAllisterracing.com Nissan NPT90 GTP body. Now what I was looking for here was a separate wing. Turns out the wing is built into the body. The wing is not high but is placed very far back from the rear axle so maybe it does not need to be so high. This should enhance speed on the straight. I'll see if the sweeper is doable. There is a large cutout to be made. The second picture shows a McAllister paint job on the pan car body. There are some short supports that hold the wing in place. It is not obvious what you are supposed to do, but I will figure it out or someone might inform me. I'll post a pick when I get it painted. I need some of that blue paint.
John
Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-nissan-npt-90.jpg   Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-mcallister-nissan-npt-90.jpg  
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Old 05-18-2007, 01:42 AM   #1299
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Quote:
Originally Posted by John Stranahan
Mamaba Max 7700 Kv Motor
First test on the den floor. The car still starts backwards a lot and then corrects itself. There are agonizing pauses before rotation starts sometimes in the hand.
John
That means the Mamba Max doesn´t work any better with the recommanded motors. I´m not sure if other sensorless ESC do have the same behavior but I wouldn´t accept this. The GM brushless ESC prove it can be done.
BTW my LRP Sphere TC spec arrived now. First race with the Sphere will be in 2 weeks.
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Old 05-18-2007, 06:25 AM   #1300
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John, not sure if you're finished with your front suspension designs or not, guessing from the fact that you've gone back to your previous design, I'm guessing no.

Anyway, have you seen the front suspension setup on the new Tamiya TA05IFS? Looks like it lowers the front suspension so that is no higher than the diff housing.


I imagine if you converted the front to the suspension from the front of this car, it would give you more adjustability and would convert your front wheels to let you run TC foams and give you an option of different width tyres and such.

Anyway, just a thought.
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Old 05-18-2007, 10:21 AM   #1301
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Sorry John, but im so happy, recived my I-Force tody and the kit looks amaizing



will keep ya informed about some uilding(not this weekend)
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Old 05-18-2007, 11:32 AM   #1302
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there was a discussion of turnbuckle shocks a while back (yeah, read through all 1300 posts! ) and the resulting conclusion seems to be that they are stiffer than they would be otherwise - and simpler is regarded as better.

I honestly believe that Tamiya seems to revel in complexity for complexity's sake, oftentimes!
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Old 05-18-2007, 02:47 PM   #1303
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Quote:
Originally Posted by Thomas P
Sorry John, but im so happy, recived my I-Force tody and the kit looks amaizing



will keep ya informed about some uilding(not this weekend)
wait a sec, he was supposed to send that to me

I cant wait to get my hands on mine...
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Old 05-18-2007, 05:50 PM   #1304
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I've been reading this thread since the beginning so I do remember reading the discussion on it but my memory is vague.

Wouldn't the stiffness depend on how much leverage there was in the hinge? I can imagine if the lengths were equal it would be stiffer because of the geometry changes. I imagine standard TC springs would be too stiff anyway with so little weight up front but with enough leverage it might be possible.

I agree on Tamiya over-complicating things. This is a great example actually, redesigning the suspension just to that a certain body can be installed is overkill.
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Old 05-18-2007, 06:08 PM   #1305
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Quote:
Originally Posted by John Stranahan
Nissan GTP ZX (NPT 90 GTP)

The first pic is a fullsize Nissan GTP ZX. The pic was stolen from here where there are more pics http://www.a2zracer.com/page92.html
There is a good You tube video of the fullsize car racing with some commentary from the current owner of one of the cars.

http://www.youtube.com/watch?v=_M2ibevE5PU

I received the McAllisterracing.com Nissan NPT90 GTP body. Now what I was looking for here was a separate wing. Turns out the wing is built into the body. The wing is not high but is placed very far back from the rear axle so maybe it does not need to be so high. This should enhance speed on the straight. I'll see if the sweeper is doable. There is a large cutout to be made. The second picture shows a McAllister paint job on the pan car body. There are some short supports that hold the wing in place. It is not obvious what you are supposed to do, but I will figure it out or someone might inform me. I'll post a pick when I get it painted. I need some of that blue paint.
John
The car that you have pictured is not the car the the body was made after. That car is a late 80's GTP car while the one that it was molded after I think raced in 90. Sorry if I'm wrong on those dates but I think that's right... I've attached a picture and if you look at it, it looks almost identical to the mcallister body.
Attached Thumbnails
Pantoura, 1/10 Pan Car, 2S LiPo, Brushless, Tips and Tricks.-nissan-npt-90.jpg  
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