DYNATUNE RIDE & HANDLING. THE WORKBOOK.
DYNATUNE-XL has been in continuous development for about 30 years in MS EXCEL. In those 30 years a total 46 different sheets have been integrated into one workbook (EXPERT Version). These originally 46 worksheets contain a grand total of more than 6 million cells, more than 250.000 cells with Constant Values, Several Thousands of Conditionally Formatted Cells and more than 500 defined Calculation Variables.
DYNATUNE-XL DOES OFFER TWO VERY HELPFUL DOCUMENTS TO ENHANCE THE UNDERSTANDING OF VEHICLE DYNAMICS
- THE 5 "MUST KNOW" FUNDAMENTALS OF VEHICLE DYNAMICS
- THE 10 "EASY" STEPS TO HAPPY VEHICLE DYNAMICS TUNING GUIDE
DYNATUNE-XL R&H KEY MODEL FEATURES - Physical limits PREDICTION
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In both versions of DYNATUNE exists a specific calculation/prediction of the physical limits of the vehicle (adapted to the complexity of the model). Furthermore are some sophisticated tools available for defining the optimal brake distribution for achieving maximum deceleration and best front to rear drive torque distribution for achieving maximum (AWD) longitudinal acceleration. After each START/INIZIALISE Calculation this upfront information will be updated.
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DYNATUNE R&H KEY MODEL FEATURES - MASSES, INERTIA's, PASSENGERS & PAY-LOAD
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DYNATUNE does offers in all versions the feature of adding up to 8 masses (passengers & pay-load) with individual positions in the vehicle. This will permit the user to simulate correct GVW conditions for all kind of vehicles or if applied in a racing environment the effect of ballast weights can be analyzed correctly.
The resulting overall Vehicle Weight, Axle Load Distribution, Vehicle Inertia and resulting Center of Gravity location are calculated automatically. |
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DYNATUNE-XL R&H KEY MODEL FEATURES - POWER-TRAIN AND BRAKE-SYSTEM
DYNATUNE-XL R&H does offers in RELEASE 8.1 the some enhanced features for simulating the effects of Power-Train and Brake-System on the Handling and Stability of the Vehicle. Most important are Limited Slip Differentials and ideal L/R Force splits as does happen in Torque Vectoring.
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The User can in RELEASE 8.1 now specify for Front and Rear Differentials whether they are open, limited slip with preload & percentage of locking and/or acting fully ideal distributing traction forces ideally on each corner of the vehicle.
It was already possible in previous Releases for AWD Systems to distribute Fore/Aft Traction Forces either in a fixed ratio or also ideally, In order to allow the User to correctly investigate in the effects of such Torque Vectoring, the 7-DOF Model and Tire Model have been updated to simulate the effects of the resulting Yaw Moment on the Vehicle and it's Effect on the Handling Balance. The above described is also applicable for Braking Forces which can be distributed Front to Rear Ideally and/or Left to Right Ideally. |
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RELEASE 8.1 is now also "EV Proof". It is now possible to activate regenerative braking in combination with hydraulic braking using the correct suspension Anti-Angles and correct Brake Power Distribution into the respective EV Powertrain resp. Hydraulic Brake System. The corresponding Results are shown on the 7-DOF Model Worksheet.
DYNATUNE-XL R&H KEY MODEL FEATURES - AERODYNAMICS
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The "RACE-" & "EXPERT" Version of DYNATUNE provide the possibility of using sophisticated aerodynamic AEROMAPS in which Lift and/or Drag Coefficients are represented as a function of front and rear ride-height (with non-linear curve-fitting allowing correct interpolation).
The AEROMAPS are an indispensable tool for any basic race-engineering analysis of dynamics on wing-cars and the feature comes with a user tool which allows direct comparison between theoretical possible maximum lateral acceleration vs. realistically achievable lateral acceleration with the installed Aerodynamic Balance. |
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In DYNATUNE RELEASE 7.1 and onward Releases additionally specific values for Tire Drag & Tire Lift Coefficients can be entered in order to calculate more accurately the Aerodynamics of Open Wheel Vehicles. If No Data is available these Parameters can be set to zero. Obviously one can also work with classical one-dimensional Drag and Lift Coefficients for the whole Vehicle.
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DYNATUNE-XL R&H KEY MODEL FEATURES - CHASSIS DATA
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CHASSIS DATA are the backbone of DYNATUNE-XL. In RELEASE 8.1 we have implemented a basic but accurate representation of a Steering System, allowing to Analyze the ever so important Steering Torque Feedback and the effects of Wheel Steer Geometry on the front Tire Slip Angles.
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Next to the usual spring and rollbar rates there is a section table available for the most important elasto-kinematic suspension data. These parameters - very established in the OEM Car Development world but very much less widely known in the Racing world - do relate to the most commonly measured data on K&C Rigs or specific output data from Multi-Body Analysis Programs like ADAMS. Using the tabular approach does allow correct parametric simulation of almost all types of suspensions. DYNATUNE does permit analysis from a rigid axle to a mono-spring open wheel race car setup with de-coupled roll and ride rate. The Chassis Data Sheet does also provide a Wheel Force Deflection Curve. Bump and Rebound Stops can be set & parametrized. |
Damper characteristics are handled in a unique sheet providing various levels of complexity and detailed ride analysis.
DYNATUNE-XL R&H KEY MODEL FEATURES - SUSPENSION DATA USER TOOL
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In DYNATUNE a SUSPENSION DATA TOOL permits the user to select from a range of commonly used suspensions the most important Kinematics & Elastokinematic Data. For those users who are not experts in K&C data this small knowledge base can provide a meaningful help in creating a correct model. The database comes with typical road suspension data and some interesting race suspension data. An automatic data population procedure minimizes margin for error in the model input data.
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DYNATUNE-XL R&H KEY MODEL FEATURES - USER TOOLS
DYNATUNE provides in all versions convenient user tools for simple data manipulation. Many times data in the wheel plane are not available or detailed spring rates, anti-roll bar stiffness are not in the right format.
These simple tools help in-experienced users or novice race engineers to calculate correct input data for DYNATUNE. Many years of application of these liitle tools show that they are also to experienced users an very appreciated help for quickly changing between various data formats.
These simple tools help in-experienced users or novice race engineers to calculate correct input data for DYNATUNE. Many years of application of these liitle tools show that they are also to experienced users an very appreciated help for quickly changing between various data formats.
DYNATUNE-XL R&H KEY MODEL FEATURES - TIRE DATA
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From RELEASE 8.0 onward all Tire Data for the BASE TIRE model & ENHANCED TIRE Model are located in the TIRE DATA worksheet. For User Convenience all relevant tire data can be plotted in convenient Graphs which allow quicker understanding of the effect of each Tire Parameter. In RELEASE 8.0 Tire Grip can be made load dependent and Camber Thrust force does enter in the total lateral grip / friction coefficient Calculation. Both features do allow further refinement of Tire can Car Performance in the 7-DOF Vehicle Model. |
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DYNATUNE-XL R&H KEY MODEL FEATURES - TIRE DATA USER TOOL
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DYNATUNE-XL R&H does come with an Empirical Tire Data Base containing exemplary parameters - based on Tire Dimensions - for the BASE TIRE Model. This Tool does also permit the user to plot all the tire parameters in a typical tire data representation graph. Next to the convenience of being able to use a knowledge base the Tool does provides also the possibility of creating your own tire car set in a very easy and straightforward way. The data can be populated into the model by automatic routines minimizing margin for error. All Data are also presented as 3D Carpet Plots. |
DYNATUNE-XL R&H KEY MODEL FEATURES - 7 DOF VEHICLE MODEL RESULTS
As can be seen above the 7-DOF-Vehicle Model does provide all the relevant Vehicle results. All Corner Loads, Suspension Loads, Tire Loads and Instantaneous Wheel Alignment / Steer Values are presented all together. See for more information the Model Website Page.
In RELEASE 8.0 Tire Operation Points, Tire Slip Angles & Other Specific Tire Information are presented either in Graphs or dedicated Green Cells (for the ENHANCED TIRE Model) allowing a more detailed understanding of what is happening at each corner of the car.
In RELEASE 8.1 all relevant Results for the New Steering System and Limited Slip Differentials and Yaw Moment have been added.
In RELEASE 8.0 Tire Operation Points, Tire Slip Angles & Other Specific Tire Information are presented either in Graphs or dedicated Green Cells (for the ENHANCED TIRE Model) allowing a more detailed understanding of what is happening at each corner of the car.
In RELEASE 8.1 all relevant Results for the New Steering System and Limited Slip Differentials and Yaw Moment have been added.
DYNATUNE R&H KEY MODEL FEATURES - UNDERSTEER BUDGET CALCULATION
In both "RACE-" and "EXPERT" Versions of DYNATUNE-XL R&H a unique feature permits to calculate the PERFORMANCE ENVELOPE of combined Lateral and Longitudinal Acceleration for various Velocities. 3-Dimensional Carpet Plots show conveniently the lateral performance capabilities under traction and braking indicating immediately where the vehicle might have deficiencies.
Additionally the user can set a Limit to the Understeer Gradient and Vehicle Side Slip Angle Gradient allowing thus also subjective Understeer / Oversteer perceptions of the Driver to be considered in defining the performance limits of the vehicle.
The calculation of the PERFORMANCE ENVELOPE can be executed with a LINEAR Calculation (predicting the limit by linear prediction/extrapolation) and a more accurate NON-LINEAR iterative calculation, which is however more time consuming due to the number of iterations needed to find the physical limits.
These PERFORMANCE ENVELOPES describe the vehicle sufficiently accurate to act as a "Black Box" Response Surface. In fact, they are the ideal foundation for a LAPTIME SIMULATION in which for every point on the track the optimal operating point for Longitudinal and Lateral Acceleration must be found.
Additionally the user can set a Limit to the Understeer Gradient and Vehicle Side Slip Angle Gradient allowing thus also subjective Understeer / Oversteer perceptions of the Driver to be considered in defining the performance limits of the vehicle.
The calculation of the PERFORMANCE ENVELOPE can be executed with a LINEAR Calculation (predicting the limit by linear prediction/extrapolation) and a more accurate NON-LINEAR iterative calculation, which is however more time consuming due to the number of iterations needed to find the physical limits.
These PERFORMANCE ENVELOPES describe the vehicle sufficiently accurate to act as a "Black Box" Response Surface. In fact, they are the ideal foundation for a LAPTIME SIMULATION in which for every point on the track the optimal operating point for Longitudinal and Lateral Acceleration must be found.
In RELEASE 8.1 All Effects of NON-EQUAL Left/Right Longitudinal Force Split will be considered on the total Performance of the Car. As one can see in the pictures below one can clearly see that limiting the Brake System to Left & Right Equal Brake Forces does limit the Performance Envelope significantly. Allowing a 50% Traction LSD does however bring the Vehicle Performance - in Traction - rather close to Full Ideal Torque Vectoring Performance.
Ideal L/R Braking & Traction (FULL Torque Vectoring)
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Rear 50% LSD and NO Ideal
L/R Braking
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DYNATUNE-XL R&H KEY MODEL FEATURES - UNDERSTEER BUDGET CALCULATION
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Backbone of DYNATUNE is the Bicycle Model. Historically BUNDORF (SAE Technical Paper 760713, 1976) defined a method to add/substract the effects of Suspension Kinematics & Compliances and Roll Effects onto this 2 Wheel Model resulting in remarkably good correlation with Real World Data.
This BUNDORF Method does define the so called "Linear Understeer Gradient". It is the most Powerfull and most Important Metric of Vehicle Dynamics as it does describe both Vehicle Stability as Vehicle Balance equally. Wrong Understeer Gradient = Wrong Car. |
IN RELEASE 8.1 The Effects of Limited Slip Differential(s) have been included in the BUNDORF Understeer Buget Calculation.
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DYNATUNE-XL R&H KEY MODEL FEATURE
UNDERSTEER GRADIENT & SIDE SLIP ANGLE GRADIENT PERFORMANCE ENVELOPES
Combining the previously mentioned "PERFORMANCE ENVELOPE PROCEDURE" with the "BUNDORF UNDERSTEER BUDGET PROCEDURE" for each Data Point of the Envelope does lead to a unique "Quasi-4-Dimensional" Graphic Presentation of the Understeer Gradient (UG) and the Rear Axle Side Slip Angle Gradient (SSAG).
Advanced Iso-metric projection algorithms permit to create and project a response surface for UNDERSTEER/SSA Gradient as a function of Lateral Acceleration, Longitudinal Acceleration and Velocity. This kind of graphic representation permits to make the whole operating range of vehicle balance visible in a few unique set of graphs. Any problematic areas of the car can be identified immediately and can be looked at in additional specific analysis. A very powerful and effective tool indeed for the expert eye.
The Procedure can be applied both in a LINEAR as in a NON-LINEAR mode and comes with 4 Pre-Defined Custom Graphs covering all combined Braking/Acceleration & Lateral Acceleration situations. Each Custom Graph provides the possibility to look at the surface plot from various angles. If wanted specific viewing angles can be set manually in each view.
Advanced Iso-metric projection algorithms permit to create and project a response surface for UNDERSTEER/SSA Gradient as a function of Lateral Acceleration, Longitudinal Acceleration and Velocity. This kind of graphic representation permits to make the whole operating range of vehicle balance visible in a few unique set of graphs. Any problematic areas of the car can be identified immediately and can be looked at in additional specific analysis. A very powerful and effective tool indeed for the expert eye.
The Procedure can be applied both in a LINEAR as in a NON-LINEAR mode and comes with 4 Pre-Defined Custom Graphs covering all combined Braking/Acceleration & Lateral Acceleration situations. Each Custom Graph provides the possibility to look at the surface plot from various angles. If wanted specific viewing angles can be set manually in each view.
DYNATUNE-XL R&H KEY MODEL FEATURES - STANDARD OBJECTIVE HANDLING MANEUVERS
DYNATUNE offers a variety of standard Handling Maneuvers in all Versions. Besides typical graphs for each Handling Maneuver a range of commonly used vehicle dynamics metrics are being offered. These metrics are many times key performance indexes (KPI) used for tracking program development advancements or refer to typical reference parameters for up-front bench-marking.
Constant Velocity LATERAL SWEEP
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CONSTANT RADIUS LATERAL SWEEP
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In the CONSTANT VELOCITY LATERAL SWEEP the Vehicle does perform a quasi-static Lateral Acceleration Sweep at a Constant Velocity. which does mean that the Radius of Curvature is tightening up with increasing Lateral Acceleration. This procedure should be applied if one is interested to examine the Vehicle Balance and Maximum Lateral Performance at a given Speed.
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In the CONSTANT RADIUS LATERAL SWEEP the Vehicle does perform a quasi-static COMBINED Lateral Acceleration & Velocity Sweep in order to keep a Constant Radius of Curvature. This procedure is should be applied if one is interested to examine the Vehicle Balance and Maximum Lateral Performance at a given fixed Curvature.
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FREQUENCY STEER TEST - EXPERT ONLY
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STEP STEER TEST - EXPERT ONLY
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The Frequency Steer Response Test is Calculated wtih the Linear Bicycle Model and does providing in the Frequency Domain the Transfer Functions for Yaw Gain, Slip Angle and Lateral Acceleration. The Test can be executed GENERICALLY or as a Function of Specific Steering Wheel Angle Input (which is particularly helpful for Model Correlation to Measured Data).
Various commonly used key metrics are available and in RELEASE 8.0 the procedure has been refined by providing automatic calculation procedures covering the complete speed range of the vehicle. |
The Step Steer Response is also based on the Linear Bicycle Model and does provide Typical Generic Time Domain Responses for Yaw Gain, Slip Angle & Lateral Acceleration. Various commonly used reference key metrics are offered in all program versions.
By providing a specific Steering Wheel Angle a real life test event can be simulated and tuned to achieve a particular final Lateral Acceleration. In RELEASE 8.0 the procedure has been refined by adding automatic calculation to cover the whole speed range of the vehicle |
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DYNATUNE-XL R&H KEY FEATURES - RESULTS SHEET & DATA COMPARISON
Both "RACE-" & "EXPERT" Version of DYNATUNE include a freely customizable RESULTS Sheet. It comes standard with all Input and Output Data of the current vehicle model and provides the possibility of setting your actual Data Set as a Reference Data Set or reload a Reference Data Set to your Actual Data Set.
All Data are stored in columns only allowing quick database manipulation, graph generation, comparison & eventual custom post-processing.
All Data are stored in columns only allowing quick database manipulation, graph generation, comparison & eventual custom post-processing.
DYNATUNE-XL R&H KEY MODEL FEATURES - TEST-Track/CIRCUIT LAYOUT TOOL
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In DYNATUNE "RACE-" & "EXPERT" Version a convenient Test-Track & Circuit Layout tool does allow an easy creation of a Test-Track, Circuit or a Rally Stage. Parting from an obligatory minimum of 4 corners and a start & finish straight, the user can create a track with up to a total of 20 corners. Any corner is defined by 5 points: Corner Entry, Intermediate Entry Point, Corner Apex, Intermediate Exit Point and Corner Exit Point. Straights are defined by Corner Exit and next Corner Entry Point. All of These Points MUST reflect the driving line on the Test-Track/Circuit. Based on the 5 corner points the corresponding Corner Radii will be calculated and if not following ideal driving line (rule of diminishing radius on entry & increasing radius on corner exit) error flags will be shown, identifying where the data needs to be corrected.
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The Feature comes with 3 complementary Test-Tracks, a typical High Speed Handling Track, a typical Low Speed Handling Track and an example of a short Generic Test-Track with 6 constant radius corners. At this point it should be mentioned that DYNATUNE has not been focused on being a Laptime Simulation Tool Only. It is far more a Tool for a complete Vehicle Dynamics Analysis providing on top of that also a Laptime Simulation Tool.
DYNATUNE-XL R&H KEY MODEL FEATURES - LAP TIMe SIMULATOR
Next to the Bicycle and 7-DOF Vehicle Model a Major Feature in DYNATUNE "RACE-" & "EXPERT" Version is the quasi-static 2- Dimensional LAPTIME SIMULATOR (without consideration of any inertial or transient damping effects).
Using the PERFORMANCE ENVELOPES as reference for the vehicle performance an optimization algorithm minimizes the time needed to drive a lap on a given circuit by finding in each corner the best compromise between lateral and longitudinal acceleration and on each straight the best braking point. Beyond that, logic decision functions are monitoring and if necessary controlling whether any modifications need to be made to these algorithms. The CONTROL PANEL shows in a typical "time table" format the most important data like section times, top - speeds and braking points both for the actual vehicle setup as for a reference setup.
LAPTIME SIMULATION can be performed either based on a LINEAR PERFORMANCE ENVELOPE or a NON-LINEAR PERFORMANCE ENVELOPE (with consequent increased simulation times) and the tool provides additionally the possibility of creating a time history data set of a simulated lap of all DYNATUNE parameters for more detailed in depth analysis of each distance point of that lap.
If desired one can execute a TIME HISTORY calculation of a Simulated Lap. This procedure creates for all Data Points on the Track the corresponding Vehicle Data. In fact it is a sequence of many specific target calculations for G-Long, G-Lat and Velocity at each Data Point. The results of this Procedure are presented iin the "LAP RESULTS" Sheet.
Using the PERFORMANCE ENVELOPES as reference for the vehicle performance an optimization algorithm minimizes the time needed to drive a lap on a given circuit by finding in each corner the best compromise between lateral and longitudinal acceleration and on each straight the best braking point. Beyond that, logic decision functions are monitoring and if necessary controlling whether any modifications need to be made to these algorithms. The CONTROL PANEL shows in a typical "time table" format the most important data like section times, top - speeds and braking points both for the actual vehicle setup as for a reference setup.
LAPTIME SIMULATION can be performed either based on a LINEAR PERFORMANCE ENVELOPE or a NON-LINEAR PERFORMANCE ENVELOPE (with consequent increased simulation times) and the tool provides additionally the possibility of creating a time history data set of a simulated lap of all DYNATUNE parameters for more detailed in depth analysis of each distance point of that lap.
If desired one can execute a TIME HISTORY calculation of a Simulated Lap. This procedure creates for all Data Points on the Track the corresponding Vehicle Data. In fact it is a sequence of many specific target calculations for G-Long, G-Lat and Velocity at each Data Point. The results of this Procedure are presented iin the "LAP RESULTS" Sheet.
DYNATUNE-XL R&H KEY MODEL FEATURES - LAP TIMe SENSITIVITY STUDY
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DYNATUNE RELEASE 8.0 does provide a new very convenient "Laptime Sensitivity Study" allowing the User to a run a Study on which of the typical track-side tuning parameters does provide the most gain in Laptime for the selected track.
Up to 20 Parameters can be selected and calculated automatically. The amount of Change of each Parameters can be set by the User and the results of those Changes are presented with absolute & relative Laptime Differences. All runs can be plotted on top of each other if wanted in order to check where the main differences are. |
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DYNATUNE-XL R&H KEY MODEL FEATURES - LAP RESULTS COMPARISON FEATURE
In the "RACE-" & "EXPERT" Version of DYNATUNE the LAP RESULTS Sheet does allow a quick comparison of detailed time history data of a Reference Lap in comparison to the current Actual Lap. This LAP RESULTS Sheet does contain all important metrics from DYNATUNE and is fully customizable - in analogy with the RESULTS sheet of the Objective Test Procedures.
A "Dynamic Zoom" feature permits to mouse-zoom directly into the graphs making closer looks & detailed comparisons very quick and efficient.
Furthermore the time history data of the Reference Lap can be exported to an external file for eventual custom post-processing or other in-house use.
A "Dynamic Zoom" feature permits to mouse-zoom directly into the graphs making closer looks & detailed comparisons very quick and efficient.
Furthermore the time history data of the Reference Lap can be exported to an external file for eventual custom post-processing or other in-house use.
DYNATUNE-XL R&H KEY FEATURES - SPRING & DAMPER RIDE TUNING
PERCENTAGE CRITICAL DAMPING
Percentage Critical Damping Charts for both "Compression", "Rebound" and Damper Velocities, Plots are available both for body as for wheel damping in continuous movement events or impact like events. A classic presentation of % Critical Damping Values.
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Front vs. Rear wheel rate carpet plots
Bounce & Pitch Center Carpet Plots as function of Front & Rear Wheel Rates. These carpet plots allow a unique graphic representation for all possible combinations of Front and Rear Wheel Rates and their combined effect on Bounce & Pitch Center Locations.
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DYNATUNE-XL R&H KEY FEATURES - RIDE TUNING DYNAMIC MANEUVERS
RIDE STEP RESPONSE FUNCTION
Transient Ride Step Input Response allowing elementary Analysis of Transient ride behavior after a GENERIC Step Input in the Time Domain with commonly used key metrics calculation.
A Basic Tool do do a "First Shot" Transient Ride Analysis in the Time Domain. The standalone Suspension Tuning Module does allow a far more sophisticated Analysis and should be considered by those who are interested to do more profound Analysis. NOT available in "RACE" Version |
RIDE FREQUENCY TRANSFER FUNCTION
Ride Frequency Transfer Function allowing Analysis of Frequency dependent Transient Damping Characteristics with commonly used reference key metrics calculation.
A Basic Tool to do a "First Shot" Transient Ride Analysis in the Frequency Domain. The standalone Suspension Tuning Module does allow a far more sophisticated Analysis and should be considered by those who are interested to do more profound Analysis. NOT available in "RACE-" Version |