velocomp Newton CdA User manual

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Newton®/PowerPod®CdA
Measurement
Instruction Manual
March 2017
Newton FW 5.15+
PowerPod FW 6.21+
Isaac software 4.1+

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THE CDA FEATURE REQUIRES FW 5.15 OR HIGHER (NEWTON), OR FW 6.21 OR
HIGHER (POWERPOD)
Use Isaac to check the version of firmware in your Device:
To see if your PowerPod or Newton (“Device”) has the CdA key installed, connect your
Device to your computer and launch Isaac. Then, go to “Device/Unlock Feature…”, then
click the “Get Unlock Status” button. If the key is installed on your PowerPod/Newton it
will be listed as “CdA Function (TT Key)”
If you don’t see “CdA Function” listed, then you will have to purchase a CdA key
for your Device
FOR MORE INFORMATION ABOUT PURCHASING THE CdA KEY, VISIT:
https://velocomp-llc.myshopify.com/products/newton-cda-wind-tunnel-
upgrade-key
CdA Key is installedà

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NOTE: FOR BEST RESULTS, WE STRONGLY
RECOMMEND THAT YOU FAMILIARIZE
YOURSELF WITH “ISAAC INSTRUCTIONS”
BEFORE READING THIS MANUAL. ISAAC
INSTRUCTIONS ARE AVAILABLE THROUGH
THE “HELP” MENU OF ISAAC SOFTWARE

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GETTING STARTED
The PowerPod and Newton are precision measurement instruments that, when used with
with a Direct Force Power Meter (DFPM), provide wind-tunnel-like measurements of CdA
(aerodynamic drag) and related parameters (“Time Advantage”).However, accurate
CdA measurements can happen only after proper setup and calibration of your
PowerPod/Newton and Direct Force Power Meter!
BEFORE STARTING CDA TESTING, PLEASE READ AND CAREFULLY FOLLOW THE
INSTRUCTIONS IN THIS MANUAL.
IMPORTANT: Make sure you review the operating manual of your Direct Force Power
Meter (DFPM), and make sure your DFPM is properly temperature acclimated and
“calibrated/zeroed”, prior to beginning CdA measurements.

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EQUIPMENT REQUIREMENTS
To do CdA testing you will need ALL of the following:
1) PowerPod or Newton with CdA key installed
a. To confirm that the CdA key is installed on your Device, use the Isaac
command “Device/Unlock Feature/Check Unlock Status”. If CdA key is
installed you will see “CdA Function (TT key)” listed in the Unlock List
2) Compatible bike computer (PowerPod only)
3) ANT+ or ANT+/BLE speed and cadence sensors
4) ANT+ or ANT/BLE Direct Force Power Meter (DFPM) (note: due to potential
accuracy issues, “one-leg” power meters such as Stages and 4iii are not
recommended)
5) Isaac software 4.1 or higher
6) Newton: Firmware 5.15 or higher
7) PowerPod: Firmware 6.21 or higher
NOTE: CdA aerodynamic measurements are tricky to make, especially outdoors. Please
follow these instructions carefully so you will get good results!
NOTE: “ONE-LEG” POWER METERS ARE NOT RECOMMENDED FOR CDA TESTING. IF YOU
HAVE QUESTIONS ABOUT A DFPM PLEASE EMAIL [email protected]

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STEP 1: SETUP POWERPOD/NEWTON
PROFILE
For accurate CdA measurements, you’ll need to customize your PowerPod/Newton profile
for you and your bike. Do the following:
1) Connect your PowerPod or Newton (Device) to Isaac
2) Go to “Device/Setup Newton…” (NOTE: “Newton” commands work both for
PowerPod and Newton)
3) Follow the setup screens, and enter your rider weight; rider height; weight of bike +
gear; “normal” riding position, and tire type and road type.
4) CRITICAL: on the final setup screen, click “BEST ACCURACY”. This puts your
Device into “Out and Back” calibration mode. If you accidentally click a different
button (“Better Accuracy” or “Keep Accuracy”, simply go through the “Device/Setup
Newton” wizard again, and click the “Best Accuracy” button on the final step)
5) You’ll get a confirmation message saying that your device’s profile has been
updated.
STEP 2: DFPM SETUP AND CALIBRATION
Because of the sensitivity of CdA measurements you need to do the following with your
DFPM:
1) Pair your DFPM to your PowerPod/Newton Device (STEP 3, below)
2) Prior to any CdA testing, ride with your DFPM for at least 10 minutes, to make sure
it is acclimated to outdoor temperature
3) Before starting your CdA measurements, confirm that your DFPM has been
calibrated (zeroed) using the “Calibrate” feature of your ANT+ bike computer
STEP 3: ANT+ SENSOR PAIRING
After installing your CdA key, you will need to do a one-time sensor pairing of your Device
to your ANT+ sensors, including your DFPM.
NOTE: DFPM PAIRING TO YOUR DEVICE WON’T WORK UNLESS THE OPTIONAL
CDA KEY HAS BEEN PURCHASED AND INSTALLED.
NOTE: FOR DETAILED INSTRUCTIONS REGARDING THE CALIBRATION AND USE OF YOUR
DFPM, CONSULT THE DFPM OWNER’S MANUAL THAT WAS INCLUDED WITH YOUR DFPM
STEP 4: OUT-AND-BACK CALIBRATION RIDE
Your PowerPod or Newton requires an out-and-back (O&B) calibration ride, to fine-tune its
tilt and wind sensors. An O&B calibration ride MUST be done each time, prior to starting
any CdA measurements.

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POWERPOD (PP) OUT AND BACK CALIBRATION RIDE
1) Make sure you have completed STEP 1 above to set your PowerPod to “Best
Accuracy”. Best Accuracy enables the out-and-back calibration ride.
2) Pick a quiet, low-traffic place to do a solo (no drafting allowed) Cal Ride. The road
can be flat or hilly; it makes no difference.
3) Make sure your DFPM is operating and that it has been calibrated properly
4) Attach PP to your bike, making sure that PP cannot rotate after its mount
screw is tightened (see PowerPod illustrated instructions for details).
5) Wake up your sensors and your PP. The PP light shows solid yellow.
6) With the status light showing solid yellow, start riding your bike. After 10 seconds
of riding, the light changes to flashing red/green, indicating that the PP is now
“armed” and to begin the out-and-back (O&B) calibration measurements.
7) Ride your bike to the place you’ve selected to start your O&B ride. PowerPod status
light will flash between red and green while you ride to your starting point.
8) When you’ve reached starting point of your O&B ride, confirm that the PP light is
flashing red/green.
9) To start O&B calibration measurements, click the PowerPod button. The light will
change from flashing red/green to flashing yellow.
10) Now, ride your bike five minutes for the “out” portion of your ride. While riding the
light will continue to flash yellow and your bike computer watts will start to climb
slowly, from 1 to 50. The power number indicates the % completion of the
calibration ride (i.e. 25W means the O&B ride is 25% complete)
11) Your bike speed during the O&B ride is not important, but DO NOT DRAFT BEHIND
OTHER CYCLISTS OR CARS.
12) After riding five minutes (the end of the “out” portion/half-way-
complete/50% completion point of the ride), the status light will change to
solid red, and watts will no longer increase, but will “stick” at 50W.
13) When it is safe, SLOW TO A COMPLETE STOP. It’s OK if you have to continue to
ride a while with the watts stuck at “50”, before you find a safe place to stop and
turn around.
14) After coming to a complete stop, get off your bike, and cross the road, turn around,
and then ride back along the same route to the starting point.
15) On the “back” portion of your ride the status light will change from solid red to
flashing yellow and your watts will slowly climb to 100W.
16) Ride back to the starting point of your ride. You can ride fast or slow and stop if
needed, it makes no difference. The watts will slowly climb from 51W to 100W
(51% to 100% complete).
17) Near your starting point the O&B you will see “100W” (100% complete) on your
bike computer. The flashing yellow light will go out. Your PowerPod is now
calibrated and, after a few seconds, actual watts will appear on your bike computer
screen.
SEE NEXT PAGE FOR A PICTORIAL DESCRIPTION OF POWER POD CALIBRATION
!
!
NOTICE: AFTER BEGINNING YOUR POWERPOD CAL RIDE, IF YOU WISH TO TERMINATE
(ABORT) IT, PRESS-HOLD THE POWERPOD BUTTON FOR ABOUT 4 SECONDS, UNTIL THE
STATUS LIGHT GOES TO SOLID YELLOW. THIS ABORTS THE CAL RIDE AND LEAVES ANY
PRIOR RESULTS UNCHANGED.

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!
!
PowerPod'Out-and-Back'Ride'

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NEWTON OUT AND BACK CALIBRATION RIDE:
1) Make sure you have completed STEP 1 above to set your Newton to “Best
Accuracy”. Best Accuracy enables the out-and-back calibration ride.
2) After selecting the “Best Accuracy” button in ISAAC, the center window of the
Newton will start to flash “do Cal”, indicating that your Newton is now configured for
an out-and-back calibration ride (Cal Ride).
3) Pick a quiet, low-traffic place to do a solo (no drafting allowed) Cal Ride. The road
can be flat or hilly; it makes no difference.
4) Make sure your DFPM is operating and that it has been calibrated properly
5) Attach your Newton to its mount, then click any button to wake up the Newton.
Speed is shown in the top window. You’ll see “----W” and “do Cal” alternate in the
center window, indicating that your Newton is set for a Cal Ride.
6) Start riding. IMPORTANT: DURING YOUR CAL RIDE, STAY IN YOUR “NORMAL”
RIDE POSITION YOU USE MOST OFTEN (FOR EXAMPLE, “HOODS” POSITION ON
YOUR ROAD BIKE, OR “TIME TRIAL” POSITION ON YOUR TT BIKE).
7) After 8 seconds of riding the Newton screen changes. “Cal” appears in the middle
window, and “Start” flashes in the bottom window.
8) If you want to keep riding and start your Cal Ride at a different place from your
current location, that’s OK! Just keep riding to your desired starting point; while
you ride to it the “Cal Start” message will continue to flash.
9) When you are ready to begin the Cal Ride, click the center button to start the Cal
Ride.Remember: DURING YOUR CALIBRATION RIDE, STAY IN THE RIDE POSITION
YOU USE MOST OFTEN (FOR EXAMPLE “HOODS” ON YOUR ROAD BIKE, OR “TIME
TRIAL” ON YOUR TT BIKE)
10) The top window shows bike speed, the center window alternates between “Cal” and
distance traveled, and the progress bar fills as you ride.
11) During the Cal Ride you can bike at a leisurely pace, and it’s OK to stop if needed.
Your Cal Ride will be unaffected.
12) Ride for five minutes, until “go bac(k), turn 180 degrees” flashes.

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13) If you still need to keep riding a bit farther to get to a place where you can turn
around safely, it’s OK.
14) When safe, slow to a STOP, then turn around.
15) Ride back to the starting point, along the same route as the “Out” portion of your
ride.
16) The progress bar empties as you ride back. Keep riding until the progress bar is
completely empty, and “Cal Done” flashes.
17) Once the Cal Ride is completed, your Newton returns to its normal screens,
and your Newton is calibrated.
NOTICE: AFTER BEGINNING YOUR NEWTON CAL RIDE, IF YOU WISH TO TERMINATE
(ABORT) IT, PRESS-HOLD THE NEWTON’S CENTER BUTTON FOR TWO SECONDS. THIS
ABORTS THE CAL RIDE AND LEAVES ANY PRIOR RESULTS UNCHANGED.

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STEP 4: DETERMINE “NORMAL” CDA
After completing your Calibration Ride (STEP 3), the opposing force (PowerPod/Newton)
and applied force (DFPM) data from your calibration ride are stored in your
PowerPod/Newton ride file.
Your cal-ride data will be used to determine your “Normal” CdA (that is, your CdA
measured from the “normal” ride position you used during your out-and-back
ride).
1. Attach your Device (PowerPod or Newton) to Isaac
2. Click on the Download Ride Data button or use the Isaac command
“Device/Download Ride Data…” A window like this will appear (your ride file content
will be different):
3. Click the “Show Download Window” button. A new window will appear (your
window will look different in its details):
4. In the box to the far left of the “Autoname Format…”, type the name you’d like to
give to your ride file (in this example, “Serotta”). Notice that the name of the ride
file in the dropdown menu changes to what you have typed:

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5. Now, click on the “Select a Ride” Dropdown menu bar. A complete list of your ride
files stored in your Device appears, with a check mark and blue highlight placed
next to your most recent ride (AT THE VERY BOTTOM OF THE LIST):
6. LOOK FOR RIDE FILES THAT END IN “CalRide.ibr”. These files are your out-and-
back cal rides. Your most recent cal ride will be located closest to the bottom of the
list, (“Serotta_01_27_2017_0937_4km_CalRide.ibr” in the list above)
7. Click on the cal ride you want to download; your download will commence
8. After your download finishes, a profile wizard will pop-up, allowing you to fine tune
your settings in a series of windows. As you click through the screens you’ll see the
same entries as you made when you performed STEP 1

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9. On the last window, make sure to click the “Send to Newton”; a confirming message
will be sent afterwards
10. Your cal ride data will now appear in the main window of Isaac
11. Now, we will determine the “normal” value of CdA as measured during your Cal
Ride. Use the command “Analyze/Check Calibration…”

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12. A pop-up window appears, asking you if you want to use DFPM data. Click the “Use
DFPM” button
13. Isaac will now perform calculations in the background, determining the best fit CdA
value between your DFPM data and PowerPod/Newton data. You will see “Before”
and “after” values in the “Calibration Changes” table. The CdA in the right column is
your measured CdA:
14. Click the “Send Profile to iBike” button to load your best-fit profile into your
PowerPod/Newton
You are now ready to start CdA measurements!
Measured CdAà
ßmeasured CdA is on right

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How CdA measurements work
The governing principle behind CdA measurement that the force you apply to the pedals is
equaled by the forces opposing the bike’s forward motion (Newton’s Third Law).
Your PowerPod (or Newton) measures opposing forces: opposing gravity (hills), opposing
acceleration (inertia), opposing wind, and opposing friction. These opposing forces slow
down the bike, requiring you to apply force at the pedal to keep the bike moving. The
forces applied by you precisely equals the opposing forces (Newton’s 3rd law), moment-by
moment.
For CdA aerodynamic measurements, applied and opposing forces must both be known.
Why? When applied and opposing forces are measured simultaneously,then CdA drag
coefficient calculations can be made in a straightforward manner.
In conjunction with a DFPM, your PowerPod or Newton measures CdA continuously during
your bike ride. Newton reports approximate Continuous CdATM numbers on its display;
after the ride, both PowerPod and Newton ride files, viewed in Isaac software allow you to
determine more precise CdA measurements.
POWERPOD Continuous CdA and Time Advantage measurements
Using PowerPod you will perform your CdA tests “in the field”. During your testing
PowerPod records both your applied forces (from the DFPM) and your opposing forces
(from the PowerPod). Both sets of data are recorded in the PowerPod ride file.
After the ride, Isaac software provides detailed, post-ride measurement and analysis of
Continuous CdA and Time Advantage.
Note that, when riding PowerPod, CdA data cannot be shown on your ANT or BLE bike
computer screen.
NEWTON Continuous CdATM and Time Advantage measurements
Continuous CdA™. By comparing opposing force data (measured by your Newton or
PowerPod) and your DFPM force data, Newton computes and displays approximate values
of CdA in real time, while you are pedaling.
Time AdvantageTM. When you’re positioned more aerodynamically (as compared with your
“normal” ride position), for the same amount of power you will go faster. Time Advantage
computes how much time you’ve gained (or lost) due to changes in “normal” ride position.
Newton displays cumulative Time Advantage on its screen.
After the ride, Isaac software provides detailed, post-ride measurement and analysis of
Continuous CdA and Time Advantage.

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RECOMMENDED TESTING PROCEDURE
Before proceeding with CdA measurements, make sure you’ve performed Steps 1
through 4 of these instructions. If these four steps are not done properly, then
your CdA measurements won’t be accurate.
Here is the recommended test procedure for CdA testing:
1) Find a spot with calm winds, very light traffic, and where the road surface is like the
one where you did your out-and-back calibration ride.
2) Ideally, you’ll want a flat course with good pavement and very light traffic. If you
can find a one mile loop that is ideal, because wind effects will be minimized (one
place cyclists use is a shopping mall parking lot!)
NOTE: FOR BEST RESULTS, CALM WINDS AND A GOOD TESTING LOCATION ARE REALLY
IMPORTANT!
3) NEWTON ONLY: Select the power window on your Newton screen
a. Press-hold the center button of your Newton (to enter Setup). When in
setup, click the up arrow repeatedly until you find “CdA off” (it might say
“CdA On”). Click the center button; the bottom window flashes. Click the up
arrow until “on” flashes. Then, click the center button to accept; “done”
flashes. Press-hold the up arrow to exit Setup.
4) Ride your bike for at least 8 minutes to allow your PowerPod/Newton and DFPM to
acclimate.
NOTE: FOR BEST RESULTS, WE RECOMMEND YOU PERFORM AN O&B CAL RIDE PRIOR TO
EACH ROUND OF CDA TESTING.
5) Now, start your CdA testing: hold the same riding position for about 10 minutes.
This allows lots of data to be gathered. NEWTON ONLY: you’ll see CdA and Time
Advantage data “rotate” on the bottom window of your power screen.
6) After you’ve gathered your CdA data for your testing parameters, try experimenting
with different ride positions, different gear, etc. Ride for about 10 minutes for
each test, and do NOT remove your PowerPod or Newton between
measurements.
7) NEWTON ONLY: you can mark each test with the Lap marker (press-hold left arrow)
8) We suggest you write down your testing configurations
9) NEWTON ONLY: During your testing, CdA measurements are displayed “live” on the
main power screen, with two significant digits.
NOTE: DURING CdA MEASUREMENTS YOU CANNOT APPLY BRAKES, TURN SHARP
CORNERS, OR BE BUFFETED BY WIND GUSTS (cars, other cyclists, etc.). IF ANY OF THESE
EVENTS HAPPEN YOUR CdA MEASUREMENTS WILL BE INACCURATE.
NOTE: WE RECOMMEND AGAINST USING “ONE-LEG” DIRECT FORCE POWER METERS FOR
CDA MEASUREMENTS. ONE-LEG POWER METERS DO NOT MEASURE POWER PRODUCED
BY BOTH LEGS.
NOTE: CDA DATA IS GATHERED ON EVERY RIDE WHERE YOU USE A POWERPOD/NEWTON
AND DFPM. REMEMBER, THOUGH, THAT CDA MEASUREMENTS WON’T BE AS RELIABLE
WHEN YOU’RE NOT DOING CAREFUL TESTING.

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USING ISAAC SOFTWARE TO ANALYZE CDA
DATA
Once you’ve finished your on-the-road CdA testing, use Isaac software to download your
PowerPod/Newton ride file.
We will illustrate CdA analysis features with an example.
Here is a file where the rider did loops of a shopping center mall perimeter.He rode in
three positions: standing up, normal hoods, and tuck. Each position was measured for two
laps (each 0.9 mile lap begins on a small hill).
This is the ride as downloaded (at this point it’s not possible to tell what the CdA test
results are):

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LAP MARKING AND ANNOTATION
We will use Isaac to mark the testing sections and to annotate them.
1) In the main window, click on the location where testing begins. A yellow vertical
line appears (in this case, we click at around the 0.1 mile mark, the beginning of the
“Standing” section):

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2) Now, with the cursor positioned over the vertical yellow line, right click on the line
and select “Mark Lap at cursor”. A lap marker will be placed where the vertical line
is located:
3) We place lap markers at every place where ride position was changed (in this
example, at the beginning of the small hill, every two circuits of the perimeter).
4) Once the lap markers are placed, click on the Lap tab to the left of the graphs.
Notice that if you select a lap section in the Lap tab, the statistics for that section
will be highlighted and the graph section will highlight in blue (here, we have
highlighted the “Standing” section:

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5) You can annotate your ride file with comments that describe test parameters for
each section. Use this command:
We annotate the first section as “Standing”, place that annotation in the Power window,
then click OK.