Boomer

three - the problem with that front end is that we can't use non-oval bodies - the true pan-car road-course bodies on it.

John Stranahan

iTrader: (27)

Three- I think I will get more shock travel with my setup than bridging the upper A-arms. Mine will also easily clear the GTP bodies. Thanks for the link. I will certainly give mine a good test before I make changes.


Marty-I see that your Pantoura came with the nice Red anodized pod side plate and motor mount. Nice.

Marty Peterson

iTrader: (3)

Yes the Red Parts are nice I ordered the car and the red parts and found once I got the box opened it had a set of red ones in it. So I have an extra set now. I was told that I got the last car they had in stock when I bought it.

Note I will be anodizing all of our cars and aluminum parts in Green , British Racing Green!

The Mamba Max is the 5700 and I will be able to tune it to make this thing Fly and if one was to run more volts the 5700 is a faster motor than the others out there like the 7700 and I have 3 of these 5700 one in my F1 2wd car and one in our Touring car and one in this pan car. and I will not buy anything else! I have had no problems at all with these motors and esc!!! I would say they are the best on the market!!!


Plus this is going to be the first Chassis I make the center section is going to be milled down 1mm from the rest of the 3mm Chassis

yyhayyim

iTrader: (26)

John: the xray shocks, even if they are just springs, wouldn't that be bsaically the same as what you have stock? The difference is that w/ the xray m18 shocks, they should have more travel.

Also, are you seeking to get both front wheels to stick to the ground when cornering at high speeds? Even 4wd TC's have hard time doing this, and even if you were to do this, what would be the benefits? It doesn't seem to be lots of benefit from a RWD car like ours, since there is no traction or power from front wheels- so what's the benefit? Or is it that you're looking for better traction and stability over bumpy sections, so you're looking for better travel from the front suspension?

John Stranahan

iTrader: (27)

YYHayyim - I have enough travel now with the MurdockRC springs and kingpins. The car is also cornering very well.
The reason for me to add shocks is to improve stability over the bumps at speeds over 50 mph.

Track Report
Track High bite-RC Pro Series Nationals, Friday practice.

I sneaked in a few runs. The computer was on and calling out the lap times automatically so this was a good time to do some experiements.

Jaco Pink vs GRP pink rear tires. The GRP's were a few tenths faster. Maybe the Jaco to run would be the grey or green. GRP pinks rears are out of stock at present.

Dual Battery vs Single Battery - 87/14 gear. This is the first time I have had lap times with both battery setups on a high bite track. The single battery was faster by a few tenths. Performance was much better on the sweeper with less weight. (The dual battery setup seems to be faster on a medium grip track, however).
I did not have the next lower gear available to test with the dual batteries. (90/14) It might have been a little faster with it. Performance on the sweeper would be the same though.

The single shock held up. No improvement yet. I still need to tune it and add the second shock. The car worked OK with one front shock.
John

John Stranahan

iTrader: (27)

Starscream (or any member of the CRC enduro team)

I noticed that you guys used BSR tires on the enduro pantoura. We never got a setup. I wonder what you guys used for the rear tires. That indoor asphalt is probably similar in grip to my treated outdoor asphalt.
John

Finished the shock work as described above. Here is a pic.

yyhayyim

iTrader: (26)

Track temp: 82F, not treated, fairly clean, outdoor asphalt. Well it seemed that team Kyosho was out at the track, and indeed 2 Kyosho sponsored drivers were present. They wrenched on their cars, set them up, and hit the track. Man they are good. Very consistent, fast, clean driving, and very calm and cool. Well, I took out my Pantoura and tried it for the first time. Took it out for a few laps to make sure its tracking straight, and that diff action is good. Preped the tires, and then slapped on the battery, and was ready to roll. As soon as I put the car down, it seems the Kyosho drivers noticed, and quickly put their cars on the track to run with me. It was us, 3. All eyes on us, the 2 top Kyosho RRR nitro pilots in town, and a simple pancar. Well I just said, "the hell with it...", and hit the throttle and drove like I was being chased by wolves, and I was...they gave me about a 5 car lead, and after the straight and the sweeper, it was kept that way. Now, into the infield, the car had sweep grip, which gave me the confidence to punch it and drive agreesively, as I'm used to, and must. Here, they came closer, and now were about 2 cars behind, and but after we hit the first turn into the big sweeper and into the straight, I again built a nice lead, back to 5 cars, and then back to the infield, where they again, were able to get a bit closer, but lost it once I came out of the infield and into the straights...things were looking nice, and I had the lead for about 8 laps, when out of nowhere, the traction wore off my tires, and they were actually able to catch up and then make a pass, from which I could not recover. By lap 10, I had to pull the car out, and again, frustrated by the lack of traction, went back to working on set up. For the second run, the car's left rear hub came loose, and this caused me to strip the spur gear. 3rd run, could not get traction again. Traction was bad after about 4-5 laps. This made hesitant to punch it and take advantage of the car's strong points, and lost corner speed. The car would just slide and spin out when trying to throttle in the corners. Rear could not stay planted, and was very frustrating. This pretty much ended my day. Will try different springs, damping, droop, etc. THese cars should be spinning out like this. They should have much more traction than any TC. But something is defenitely off, especially when TC's dont need tire sauce to stay hooked, while 200mm pan cars, with twice the rear tire width of TC's, cant stay planted unless you use tire sauce? Something must be wrong...it should not be wroking this way. I belive a pan car should hook up nicely with those size tires, and only need tire sauce to enhance/perfect already good traction, or to get that edge where you can take it to warp speed.

Pro ten Holland

iTrader: (1)

Cool story!
First advice:
Drive slow to be fast. Works in any category of racing. Your the fastest when you think you're driving slow, but hitting every apex just right. Traction will stay in that way.
Second advice:
Never, never ever use full throttle in a corner. That's just throwing away speed and traction.
Third advice, and that's only when you've mastered 1 and 2!!: Use thinner oil in the center shock. This will keep the rear planted better under throttle.

Last: a nitro sedan doesn't need traction compound because of its weight. Make your pancar weigh 2.5kg and you won't need traction compound as well.
We apply traction compound to kind of "fool our tires into believing they are warm". Our cars are just too lightweight to get the tires up to optimal running temperature. Consequently, on a hot day you sometimes don't need to use traction compound.

Marcos.J

iTrader: (239)

for traction try using paragon first and immediately after soak the tires with SXT or Tire tweek, let it sit for about 30 minutes then wipe it off and hit the track!

John Stranahan

iTrader: (27)

Thanks for the report and tips guys. I will add my own. When I started running this pan car my traction wore off early. Here is what I think happens. The car is very powerful with a 4.5. It's a kick in the pants to spin the rear tires once in a while. You can do this just about anywhere on the track. If you do this by choice or by accident you wear off a significant amount of your treated layer of tire. When you learn to roll on the throttle at exactly the right rate, you get super acceleration and lower tire wear and longer runs on the treatment.

Front Shock Report, Track High Bite
I am running two front shocks now. I was able to lower the spring tension in front to the next lower spring (purple progressive MurdockRc). I could not get the car to blow over anywhere on the straight. A couple of times the car hit bumps early in the straight and left the ground level. This is new and desired behaviour. Later in the straight I could get the nose to lift on some bumps still (with heavy throttle), but the chassis was not bottoming with the 40 weight oil and purple springs. No new scratches underneath. I can probably drop to 35 or 37.5 weight and be better still. Sweeper is better than before. The rest of the track is unnaffected. The car feels great.

Here is a pic of the Associated MiniT shock which when compressed is the same length as my shortened VCS micro shock. The difference would be in how you mount the body of the shock to the bumper. This would be prefered for maximum steering throw. I have plenty of throw with my current setup.
John

Boomer

There's actually a really good reason why TC's don't require traction sauce, actually two and they combine:

1. Weight. Pan Cars are so light that they don't create as much friction between the tire and the asphalt. This means less traction without aid (or aerodynamic downforce)

2. Size. With a narrow tire, there is a higher amount of pressure, per square whatever (mm, in, whatever) - it's the same principle as with a regular pickup or a dually - a dually would seem to have more traction, but if the same light weight is in the bed, the dually actually has a bit more tendency to slide - there's not as much weight per square inch on the ground. A narrow tire with light weight will grab more, to a point.

Our fat tires are superior when we aid them - and give them an increased friction factor. We could go with super-soft compounds, but then we'd pick up all sorts of dust (and lower traction) OR it would grind down to nothing.

Instead, we add a compound which aids traction and keeps us with fairly long-lasting tires and gives us the full potential of the size of tire.

I hope that makes sense - if anyone wants to interpret my ramblings, go ahead!

John Stranahan

iTrader: (27)

Well I can add ramblings of my own

A rubber tires traction on clean asphalt is straight forward. The more surface area on the tire the more efficient the tire becomes and the more cornering force can be developed on an axle. The less the load on the axle the more the cornering g's that can be developed

Forward traction for a rubber tire on asphalt is even more straightforward. The more load on a tire the more forward traction. The more the surface area, the more efficiently the tire creates traction (there will be less slip). Load is increased by front to rear weight transfer. With poor throttle control, I can completely unload the front tires with my pan car and cause a corner exit spin (ice skater type spin). I can get all the weight (no matter how it is distributed) on the rear tires.

In very soft dirt things change. Here the pressure on the surface of the tires start to dig the tire into the dirt. A wider tire will have less cornering traction on dirt if it digs in less. This is opposite to the way rubber tires behave on clean asphalt.

Now our pan car tires generally follow the rubber tire rules on clean asphalt. I get tremendous forward and cornering traction from the wide rear tires on a high bite track. When the track is a little dirty or dusty things change. The tire now has to get through the dust to get traction (more like a tire on dirt). The narrow touring car tires do this better. A heavier battery may create more cornering and forward traction on a medium bite track, because it gets through the dirt better.

Traction compound seems to help the wide foam contact the asphalt better. Just use some. I suggest Jack the gripper. I am following good advice and have tested it against some other compounds as well. When you try it you won't go back.

So how do you tell if you have a high bite situation. Well the pink rears and purple fronts will throw little rubber bits all over the body and chassis. The car will be wicked fast. The tires will wear. If it is really dusty, like it was the other day with 50 mph gusts, when you spin out the chassis will throw out a little cloud of dust that will stain the track at the scene of the incident. When you pull the body off, the chassis will be covered with dust. There will be nothing on the body. Not a spec of rubber to be seen. The pan car will be slower than those other cars on this type of surface. The dust is interfering with contact. Then there are situations in between where my car is generally as fast as the Nitro cars, but only after I have learned to roll on the throttle at the right speed. The only way you can tell if you are spinning the rear tires is that you notice the car does not accelerate quite as fast as that one time where you did it just right.
John

John Stranahan

iTrader: (27)

More on Front Shocks

I had a good test of the front shocks. 40 minutes of track time. They held up well. I had the best results with dual batteries. It almost felt like I had a front suspension now. The car left the ground level most of the time. High speed stability was good. With one battery I had the front bouncing up some. This might only mean I need to retune with a softer spring. I will try this next. Grip on the sweeper was outstanding with the purple MurdockRC Progressive front spring. I have installed the lighter green for the next test. I was using 35 weight oil for this test. I'll get some lap times on our December 3 rd club race to see if lap times were improved by putting shocks on the front.

I tried 90 spur 14 pinion with my Novak 4.5 R. This might be good for my endurance run, but it was topping out on the straight and a little too punchy. 87/14 felt great. There was some leftover traction from our recent Nationals.

I did an install of the Mini T shock which might be a better shock for this application as the ends are stronger and there are no threads on the plastic bodies that need to be removed. Here is a pic. Note that I have installed the bottom end with a bushing, but it actually will snap over the ball that was on this blue KSG sway bar link end. I am using the ball now. The proper ball would be a 4 mm ballstud.

Joly Joe Junker

Hi
you make a mistake in calculating rollcentre
once you have found the instantanious centres (were the lines of hte arms meet) you then need to draw a line that from that point back to the middle of that tyres contact patch on the ground. were this new line passes the centre line of the car is the roll centre hieght. so altering the angle or hieght of either arm will change RC.
I do apologise if this has been cleared up elsewear I did read every page but there are quite a few.
Also with making the car heavie and going faster consider this.
Two of the main factors that produce grip in tyres is this
molecular atraction:
this force is small but happens frequently within the imediate tyre on the ground. On wet and dusty tracks this force is reduced to negligabel levels.
Indentation and deformation forces:
This is basically the tyres surface conforming and 'locking' to the small edges and iregularities of the surface (aggregate)
in large scales (ie real cars) this occurs at virtually any tyre wieght because of the sheer wieght of a car.
With models then it is perhaps possible to run too wider tyres not getting the indentation forces of the tyre to work properly?

Josh

John Stranahan

iTrader: (27)

Josh-Thanks for pointing out this error. I agree that the following statement I made is in error. I did add a roll center diagram later that was in line with your correction. I should have been referring to the instant center here. Thus the rest of the text you quoted is in error as well. Thanks for the discussion of tire traction.

" Our pan car front always has the roll center at the level of the lower arms no matter what you do with the upper arms in my opinion"

Our pan cars have a lower fixed arm and an upper active arm. The motion is more like a car with a strut than a twin active A-arm car. This has caused me the difficulty. The steering block makes an arc as it travels upward. The center of this arc would be the instant center not the roll center (as you point out correctly).

I see now that changing the position of the upper arm inner pivot will change the radius of the arc. Lowering the upper A-arm pivot should reduce the radius of the arc bring the instant center inward and move the roll center upward.
Josh tell me if you agree with this last statement as this is a common way that adjustments are made to this type of car.
John