Nathan Wilson

Hi bob, do you have to use a 2 off 2s lipo as shown in instructions ? can you use a 1 or a power supply?

in terms of finding the strongest motors what figures do you look for?

Thanks

C@T

Has anybody made a model for a Serpent Cobra GT 1/8 scale car ?

BobW

iTrader: (1)

Since the dyno is powered by the Battery Pack I'm pretty sure you need to use 2S. The specs say 6.6V-7.4V input.

You don't need to use two packs though. When you test 13.5T motors you may need to use 2 packs because of the higher current draw. Otherwise you may start popping fuses.

Hard to give a simple answer on what to look for to pick the strongest motor. Obviously peak power is one number to look at but you also need to consider the width of the power band. A motor with high peak power and a narrow power band will get outperformed by a motor with a lower peak power and wider power band. What it really comes down to is torque. Torque directly relates to acceleration so a motor with more torque at higher RPM wins.

What I do is run motors at several different timing levels and create a model of each one. Then use the Acceleration simulation to compare head to head what happens as you change timing/gearing to see which car gets there first. The other important graph to look at is current draw. Some motors will draw massive amounts of current at higher timing settings. Their KV value and peak power may look good but the high current draw will make using them on track impractical due to heating.

Combining track testing with the simulation will provide insights you can't get any other way. You will definitely find the sweet spot faster and should squeeze out more speed without having your motor melt down.

BobW

iTrader: (1)

Uploaded some new models and updates, ARC R10 2015, Spec R - R1 and Schumacher KF2.

Also check out the pic and say hello to the latest addition to my pit box.

EDWARD2003

iTrader: (8)

I'll be attending AOC Japan and I'll be brining my RC Crew Chief program with me. Those who are attending this are more than welcome to stop by my pit and check it out

maris

Hi Bob,

Strange nuance - I can't get CGhght permanently to zero (in Weight Transfer -> Adjust Car Values). If I set it to zero (0 is adjustment, full CG height is at 38.3 then), go to setup, press save. Then load different car, and back this car, it has been reverted to -4.6 and total CG shows as 33.7. It looks like even after I hit Save in setup tab, it goes back to 4.6.

Changing height changes this to something like -3. Where is it stored? Is there a way to permanently get it to 0, no adjustment?

I think I have latest version - V4.1.0.3.

Thank you

P.S. Digging some more I found that it looks like it thinks that 38mm CG is at height 22. But in reality it is at height 16. And I can't find a way to change it so that it's zero at 18 and then is adjusted. Maybe it's at zero at 22 because 22 is kit height?

BobW

iTrader: (1)

Hi Maris,

The way the program works is everything is referenced to the base geometry entered in the chassis manager and car manager. So what this means is your base ride height is the value entered in the Chassis Manager when the Car was measured. Similarly the base CG position is set by the values entered in the "Car Manager" once you have assembled all the components.

From this point on everything is calculated relative to these values. So now in the setup page if you lower the front/rear ride height by 4mm this will lower the CG by 4mm. If you save this setup and move on to the Weight transfer tab and click the adjust Car Values button the CG height should show as -4mm since this height is referenced to base CG Height value entered in the Car Manager. Note that Car Values does not permanently change anything.

So if you want to permanently change the CG reference value based on your measurements then go to the Chassis Manager and change the Front/Rear ride height to your setting and save. Note that changing the ride height also changes other elements in the geometry so to be 100% correct the other Front/Rear suspension measurements should be adjusted as well since this will now become the reference geometry for all calculations. Then open the Car Manager and enter the CG values you have measured and click save. Now everything will be referenced to those values.

maris

OK, it makes sense to measure everything against one reference Height. I don't think it's wise to change that in Chases Manager. That means that to correctly calculate CG height I need to setup ride height of my car to 22/22 and then do CG measurement where I lift the car, right? Or would it be fine to measure CG when let say car it at 18mm ride height and then just add 4mm to CG? I mean to add 4mm to CG height I enter in Car Manager main window.

I'm afraid that currently as my car is set up I can't get front to 22mm, I run out of shock preload.

Interestingly enough now when I looked in Chasses Manager I see there is measurement for Tire Dia and Tire Width, but they are also in Setup page!? How is that handled?

Thank you,
Maris

P.S. I'm will be trying out Touring class and buying XRAY T4 So will have chance to try RC Crew Chief with T4 which should be how it was originally intended to use. Not that I have found anything wrong with using it for buggy.

NOS1K

iTrader: (4)

Cool software

cdraughon

iTrader: (3)

Bob,

When measuring the bellcranks, does it matter what direction the system is facing? I'm measuring my TLR 22 2.0 and the crank faces toward the servo instead of away from it. Compared to the Measurement Worksheet, it looks backwards and I'd like to know how to make the model look like the actual system.

Thanks for your continued help as I navigate the learning process on this cool tool.

Chris

BobW

iTrader: (1)

Best would be to measure the CG the way you have your car setup and just change the Ride height setting in the Chassis Manager. If you are really ambitious you can also adjust the camber link length but that is not critical.

When you change tire diameter the program will recalculate the suspension geometry to maintain the set ride height and camber settings. If you change tire width the track width will increase or decrease accordingly as it assumes the same wheel offset from the tire centreline is used.

You will enjoy TC it's a blast.

BobW

iTrader: (1)

If you are talking about the buggy with the slider rack then the direction the ball studs face will not matter as the rack motion is linear. If you are using a dual bell crank system then the direction the crank arms face definitely has an impact as the rack now moves in an arc so the direction of the arc and it's position relative to the steering hub will have a definite affect. You can get the current model to work with a reversed bell crank but it takes a little works to mirror the model so the geometry is correct. I can work that out for you if you send me the measurements. The graphic model in the program will display as it shows on the measurement worksheet though. I have a reversed bell crank steering system on my to do list.

cdraughon

iTrader: (3)

Ok, that's what I thought. I think I have it pretty close - was able to use the model view and some negative values. I'll send the measurements to you and what I input for your reference. Thanks!

Tdub77

iTrader: (2)

Hi Bob, is there a way to keep droop consistent when changing shock positions. Example, when I have 5 mm of droop but then I change the position of where the shock is mounted, I want to be able to know how much I need to adjust the bottom eyelet on the shock or and/or add or remove limiters in the shock body.

I hope this makes sense to you.

Thanks

Tim

BobW

iTrader: (1)

When you change the upper shock position the change to droop should be very small. Moving the lower shock mount inward or outward will certainly have more of an effect.

I'm working on shock modelling now which will require more details of the shock geometry and stroke to be included. Shouldn't be to much problem to include something to calculate the shim thickness required to maintain consistent droop. I'll add it to the list.