John Stranahan

iTrader: (27)

And I thought the best part of the associated front suspension was that upper arm with the vertical arm mount to make it rugged, easy caster and reactive caster change. I don't like the rest of the associated front end much, but I have not run it on carpet yet. Our carpet track is dried in now. Won't be long.

Traction Medium, 75-80F
I emptied a couple of packs today by running until the car slowed to make sure I had corrected the problem I had in the last heat of the previous race (car slowed to a stop, then recovered). The new bearing solved the problem. I am using grease. I noticed slower speed on the straight, but this may just have been a traction problem as the 1/8 scale guys reported dust on the track. I don't see this bearing offered with a single teflon seal yet. It might be worth a try.

The car slew all commers including 1/10 scale nitro and Spec 1/8 scale. I was pretty even and passed a 1/8 scale open mod car. He was handicapped by driving from track level though.

Motor Cooling
My highest motor temp was 156 F. I made a small cutout in the molded in vent on top of the cockpit of the Toyota GT1 body. This cooled the motor by about 5-10 degrees on the next few runs. The car handled slightly better as this settled the nose of the car a bit. The center of downforce was moved slightly forward.

Moved weight rearward
I made weight distribution changes to the car. I moved the transponder and receiver back to the rear crossbrace. I could roll on the throttle just a bit faster than before. The car handled really well. I made sure that my vinyl tape 3mm soft dam was in good condition to prevent blowovers after lightening the front of the car a little. No problems here to report.
John

John Stranahan

iTrader: (27)

Here is a mockup of the chassis with the battery layout I desire. It looks like the 4 rear cells will fit between the existing lower links. I measured some new fat cells to make sure. There will be a T-shaped brace like my current cars have anyway to secure the batteries. 4 cell will be a snap. Lipos can fit as a single pack in the middle or dual packs side by side. I am hoping 3/16 width on the graphite will be enough at the very back of the packs. Front end is looking like a go. I noticed that both trailing axles and inline axles are available for this RC10B4 caster block. I have some inline axles coming. 5 and 0 degree caster blocks are available. Intermediate casters can be shimmed in. No reactive caster will be available, but I don't miss that at all on my present front suspension.

The upper arm will be a bit higher inboard once the mount is finished.
John

CristianTabush

iTrader: (13)

John, what kind of shocks do you need that size springs for???

John Stranahan

iTrader: (27)

RC 18 T front shocks. I need heavier than stock springs for my pan car front end. What I am doing now is shortening the spring for a VCS Micro Shock to about 3/4 inch. That leaves me with one end that is not well formed for a spring seat. They work OK. I am using the red vcs (14 lb/in) spring. (.0475 inch spring wire diameter).

Two more small pieces of Aluminum to mill and I will have a working prototype with the Mini-T Aluminum arms I just ordered from atomicmods.com or the stock plastic arms. A couple of days maybe. I butchered up my old blue arms doing investigations.
John

CristianTabush

iTrader: (13)

The SAS springs you ordered will fit over the shaft, but not over the shock. It might work well though, I'll dig around my sources and see what I can come up with... I thought maybe M18 springs, but the I.D. is too small.

John Stranahan

iTrader: (27)

Thanks for looking. I'll see if there is room below the shock body when I get the prototype finalized. Photo from above http://www.rctech.net/forum/attachment.php?attachmentid=219197

Those were RC18T front shocks not Losi.

Note that I plan to use the stock Mini T size pins. They are similar in size to the upper A-arm pin on the Associated front end. The e-clips are tiny, but they will provide good clearance at full lock on the wheel instead of biting into the rim. There will be a crash shock absorption system on both arms similar to the associated upper suspension arm mount. This should save the pins and the arms in most crashes. I'll test it to see. I have fit 1/8 inch pins satisfactorily as well. Seems to be more weight than needed on a light pan car.

John Stranahan

iTrader: (27)

Mini T based front suspension

I have one side of this Front Pan car suspension operational now. I still need to locate it on the car properly. Here are some things that I like about the suspension.

Long Arms for good traction on Asphalt

Upright plastic suspension arm mounts that have some twist to them to absorb shock in a crash. This is the reason that Associated Pan car upper arm hardly ever breaks.

Shim Adjusted camber. I tried this adjustment today to set up a realistic camber for the photos. It was easy. I used two round plastic spacers for a 1/8 inch shaft. Associated narrow washers as well as kingpin shims will work. The good part here is the camber won't be changing when you tap the boards. The shims are located inboard of the plastic suspension arm mount that holds the inner A-arm hinge pin.

Shim adjusted roll center. Each suspension arm is mounted to plastic then to a square Aluminum bar. This aluminum bar can be adjusted up on both arms with shims to set the roll center.

Outer upper arm is high near the wheel for positive control of camber. I have found this is more important than the actual camber itself.

Lower outer hinge pin for good wear. This gives positive control of camber.

Will fit under the GTP bodies.

It should work as good as my previous front suspension due to unequal length dual dynamic A-arms.

A set of the four plastic arms are around $2.00. I kid you not. The four Aluminum arms are $20 for the set.

A production suspension would have machined plastic suspension mounts similar to these altered Mini-T plastic mounts.

A production suspension might also include some lightening holes and a blue finish on the Suspension Block.

A droop screw which is hidden in the photos. It is a 2 x 56 button head screw on the inboard side of the back of the lower arm. There was room on the plastic arm to mount one here as well.

The suspension is extremely supple without the shock on.

I am pleased at this point. Maybe a road test on Friday or Saturday.

John Stranahan

iTrader: (27)

Mini-T based front suspension

Close to a test. Need to mount electronics. You can see the droop screw on this shot.

John

syndr0me

iTrader: (32)

John,

Even though the focus is on the development of your car, your input on the other components you use is really valuable also. You're pushing newer technologies like brushless and LiPo to their limits, which has been nearly as interesting to me as the progress you've made with the pan car. I secretly hope you find a reason to try out some of the new generation of 3.5 brushless motors, you convey your experiences more clearly than anybody else on this forum.

John Stranahan

iTrader: (27)

Syndrome-Thanks. Well give me a link. I thought I was using the 3.5 brushless motor. I do have a Tekin on order and am going to experiment with higher voltage when it arrives. The car was as fast as an open mod 1/8 scale last time out in practice. We have a race Sunday. Here is a pic of the top view of the front suspension. The upper A-arm plastic mounts are slightly different. This is a temporary thing as I get my alignment right. I drilled new holes in the bottom of this large servo saver to eliminate bump steer and get adequate steering travel. The roll center is low and appears to be about exactly where I have it on the other car. When you remove the bump steer your steering links will point right to your instant centers. My traction has greatly improved with this new front and rear suspension. I am averaging well over 30 amperes during a race now. I have some new MaxAmps.com LiPo batteries on the way. 4000 mA-h. This will allow completion of a heat on 80 -90% charge. It is hard to get a full charge on race day due to the long 3rd stage of charging.

John

syndr0me

iTrader: (32)

John,

Orion has a new 3.5T brushless out that has a sintered rotor, vent holes in the can, as well as an internal fan built into the rotor. That one is available online at most shops: http://www.teamorion.com/Products/Motors/Brushless.

LRP has a 3.5T in their new X11 series that seems to be forthcoming. I see their 4.5 in the online shops, but no sign of the 3.5 yet. It's listed on their site, complete with specs, however: http://www.lrp-electronic.de/e/lis/0...-Features.html.

Graupner/GM has some new motors coming out, some of which can be purchased as both delta and wye/star wound. They too have a 3.5T, which I believe has Hall sensors, but can work in sensorless mode as well: http://shop.graupner.de/webuerp/servlet/AA?wgr=853.

I believe all these motors are compatible with the GTB. The Grapner uses a different sensor connector, but I think they come with an adapter. I believe these are the motors that were used by Marc Fischer to win 1/12 Snowbirds this year.

Anyway, sorry to stray off-topic, it just seems like in your quest for speed and reliability, you might find some interest in the other fast brushless offerings that are coming out.

Keep up the great work, this is truly one of the best threads in this site's history.

syndr0me

iTrader: (32)

I don't know about the cells MaxAmps use, but the Kokam cells used by Orion seem to be able to handle a 2C charge rate without noticeable reduction of cycle life. Perhaps the fellow at MaxAmps can tell you what to expect with his cells charged at 2C? If it doesn't significantly affect cycle life, it should cut down your charge time significantly.

yyhayyim

iTrader: (26)

Dear John:

Have you tested the Mamba Max ESC? It handles more power than anything in the market, and so easy to set up. It can take abuse and has alower profile since it doesnt need cooling fans. Their motors can take 200F, and dont thermal. I have tested them for past few months and they are so good. The Mamba Max is my favorite ESC now. Also, Team Trinity has their awesome N60 brushless motors, which weight only 156g!!! that's a huge weight difference from Novaks 190g!!! The Trinity N60 motor is a mod motor which is as fast as a 3.5R motor, but has a significantly more power/weight ratio, and runs a lot cooler, than the Novak motors. Has anyone else tested them?

Mamba Max: http://www.castlecreations.com/products/mamba_max.html

Trinity N60: http://teamtrinity.com/shop/motors/brushless-n4060.html

Boomer

John,

How do you change camber with shims? I can see changing caster with shims, but I didn't see a camber change adjustment. . .

John Stranahan

iTrader: (27)

Syndrome-Thanks again. Brushless is certainly not off-topic in this thread as the title contains brushless and Lipo. We have discussed The Novak GTB and the Sphere comp in this thread as well as the 4.5 and 3.5 Novak motors. Three of us are running the Novak GTB 3.5 with good success. There are some thermalling issues in hot climates like Azmio is running in already. Maybe some here in August. Of the motors you have listed the Orion motor with an internal fan sounds the most interesting to me for a 140 F-150 F track temp. Thanks for the information and the links. If I have Thermalling problems this summer I'll consider it. I'll do some more reading on the matter.

My thought at the moment was to run a 6.5 at twice the voltage to solve the thermaling problem. High currents, which cause the heat, should be greatly reduced.

My previous packs were Apogee Magnum's which had a recommended charge rate of 2C. I used this and they lost runtime about as fast as a NiMH. Way too fast. My MaxAmp packs, I charged at 1 C most of the time. When you are racing though sometimes you crank it up a bit to make runtime. They lost capacity after about 60 cycles but this is not as fast as the Apogee's which I charged faster and not nearly as fast as NiMH do. Because they lost runtime and volts I think the two brands, Apogee and MaxAmps are the same type. Lithium Manganese packs. My original Scorpion Lithium Cobalt Dioxide pack did not loose runtime or Voltage over 30 cycles.

YYhayyim-I looked over the Castle Creations Web site. The information there seems to be over the edge, very misleading. I am not attracted much by the size and weight of their speed control case. I'll have to give it another look based on your report. Lack of thermalling issues may outweigh any disadvantages. I am going to try the Tekin next as I have it backordered. Thanks for the link on that Trinity motor. It should work with the Tekin. I like Trininty motors as a rule as they are generally concerned with function.

Boomer-If you look close at the last picture you can see that the inner hinge pin on the upper arm goes into a black piece of plastic. This plastic mount is flat and is bolted to the side of an aluminum block. The camber starts at about -3 degrees with no shim. You add shims between the plastic mount and the Aluminum block to move camber toward 0. 0 camber would take the largest shim stack. There is also some room for shims on the lower arm and mount. Shimming the lower arm out would widen the width a little and move you toward more negative camber. I'll put up a pic in a bit.

I have looked at two piece aluminum arms with a turnbuckle built in with screws to lock it. They seem overly complex. I hate single tie rods like they use on touring cars. They make the suspension fragile and often telescope in the crashes. The associated upper tie rod gets loose with a little use and turns by itself. Anyway this system with shims worked great on my full size 1968 car. It should work great and not need constant attention on the pan car as well.
Pic
You loosen the two button head screws at the top of the suspension block. The arm unfolds. You see what's in the pic. Now you have easy access to a very simple plastic suspension mount. You can see the two black plastic spacers/shims and also two narrow white Nylon spacers/shims that I used to give me about -1 degree of camber. The plastic mount can also be reversed by swapping it to the opposite side of the car to make huge changes in camber. This piece of plastic will also twist on the screws on its installed vertical axis. That will give the suspension some crash resistance before it fails. (Note that this can be done from the side without undoing the aluminum block). The entire little aluminum block can be shimmed up to lower the roll center. The lower arm can also be adjusted the same way. If you shim the lower arm up you raise the roll center. The fact that the Aluminum upper arm on the suspension block is not supported in the back will give it some springiness as well to help protect the upper arm. On the plastic arms the upper arm is significantly stiffer than the lower arm so I gave the upper supports more springiness or twist action in a crash from the front. The lower arm's aluminum mount is more solid and has a firmer plastic mount with screws more widely separated.

Caster is adjusted with the purchase of the 5 degree or the 0 degree caster blocks. Then it can be fine tuned with shims. If we end up CNC ing the caster block in Aluminum then maybe we can have an intermediate Caster block available.

Note that eventually I plan to just run plastic arms on the asphalt. I am going to give these aluminum arms a try though and then try them later on the carpet track when it gets done.

Question
I have studied the links. That sphere comp motor looks like it takes a special Sphere comp (TC spec) speed control. I don't see that control listed on the Team Associated web site. Is this a new updated controller as my old one fried on a Novak 3.5R.

John