Is Watts/CdA a good predictor of Time-Trial Speed?

Is Watts/CdA a good predictor of Time-Trial Speed?

A recent Scientific Triathlon podcast argued that the best predictor of average bike-speed on a flat course is watts per CdA.  If your watts per CdA is higher than the rider next to you, you will beat that rider in a flat time-trial. [This is in contrast to watts/kg, which is the best predictor of climbing speed.  See my blog on the Tron Bike for a discussion on watts/kg.]

Most of us triathletes do power-based workouts on the bike.  We work on increasing our Functional Threshold Power (ftp) and have a good feel for the average wattage we can produce during a race. But do any of us have a handle on what our CdA is? And how do we reduce it?

What is CdA?  CdA is the coefficient of aerodynamic drag multiplied by a relevant area. Area(A) is usually taken to be the frontal area of the object, but in reality, Cd and A are rarely treated separately. CdA is a measure of resistance as a body moves through a fluid. It is a function of both the size and shape of the body and density and viscosity of the fluid. If you are a bigger person, your shape is bigger, so you may have a higher CdA than a smaller person.  On the other hand, if the larger volume of muscle generates more watts, it likely will overcompensate for the additional "area" of that muscle.

Back to the title question: Is Watts/CdA a good predictor of Time-Trial Speed? The answer is 'yes', but it is almost worthless in practice, because no one knows their CdA!! Even most CdAs of professional cyclists reported in the literature are not directly measured but are calculated from their speed and watts.  You can do the same. Go to the chart below and find your average moving speed for a recent time trial (or a flat bike leg of a triathlon). Find the watts/CdA that corresponds with that speed using the dashed curve. Divide your average watts for the time-trial by that number. That is your CdA x1000.

[Example: If your speed was 20 mph, then Watts/CdA x 1000 is 0.5. If your average watts for that event was 160, then 160 watts / (1000 x 0.5) = 0.32 m² for your CdA.]

The points [blue squares] on the chart above were gathered from the internet and from friends who shared their watts, speeds, rolling resistance data, and air density. [A slightly more sophisticated estimation of watts/CdA can be done with this additional data.] The pink line is the theoretical watts/CdA if one ignores everything but aerodynamic drag (no power losses from drivetrain, rolling resistance, elevation gain/loss, wind, etc.) Are you surprised at how irrelevant the other factors are in predicting race speeds on these flat courses?

Note especially that nowhere is rider weight or bike weight part of the equation! Weight only effects the speed when there are changes in elevation or accelerations. At constant speed on a flat course there is no penalty for a heavy bike! If the extra weight is due to aero features of the bike, a few additional kilos is an advantage on a flat course.

Now that you know your CdA, how do you reduce it? That will be covered in Part II.

Captain Jacob Conklin's Company in the Ulster 4th Regiment of Militia

In a prior post, I puzzled at the absence of Joel Campbell in the 1779 Tax Assessment for Hanover Precinct. Joel's presence in that area before and after that date is known through the 1767 Coldenham Store records, 1770 New Hurley Church records, the 1790 Montgomery Census, and the 1779 list of Exempts from Jacob Conklin's company of militia.  Perhaps if I could trace the whereabouts of Captain Conklin, I could make some guesses as to the whereabouts of Joel and his family during the war.

At the start of the Revolutionary War, Jacob Conklin was 34 years old and had 6 small children.  His house appears on a 1780 map drawn by Simeon DeWitt. It appears to be located at the north side of the intersection of Quaker St and Church St in what is now the Town of Plattekill.(41.604984, -74.093930).  That location is on the current border of Ulster and Orange Counties and on the borders of Plattekill and Newburgh towns.  Plattekill was created from the Town of Marlborough in 1800. His residence in 1779 might have been considered to be in Newburgh or Marlborough. It was about 4 miles NNE of Samuel Campbell’s original farm, where Levi and Nathan appear in the 1779 tax assessment of Hanover.

Conklin's militia was known as the "Western Newburgh Company" and was said to be "recruited in Wallkill." [see Article in New York Genealogical and Biographical Society Journal, Vol 59 Issue 4 p223.]  As I have discussed before, "Wallkill" had many geographical meanings. In this case I believe it meant the enlistees lived closer to the Wallkill River than to the Hudson River.  The use of the term "recruitment" suggests this was a special company, as militias were typically not recruited, but obligatory if you lived within the geographical boundaries. What it might be referring to is the company that Conklin led to New York in 1776. It was recruited out of other militia companies for this out-of-county duty. (Usually, militias were formed to protect their locality and had no obligation outside of the county).

Jacob was commissioned a Captain on October 11, 1775 in Colonel Jonathan Hasbrouck's regiment of the Ulster County Militia.  His wealth and education likely qualified him for such a commission as there is no evidence of prior military experience. 

In late 1775, New Yorkers led by General Montgomery invaded Canada. According to the pension deposition of Ephraim Oakes, Jacob Conklin was a fellow soldier in the company of Daniel Denton and Robert Johnson in the regiment of Colonel James Clinton. This service is not mentioned in other family records, but such experience may have qualified him to lead a company of 4-month Ulster levies to "New York" in the fall of 1776.

The siege of Boston ended in March of 1776 with the British evacuation.  One month later, in April 1776, the first surviving muster of Captain Conklin's militia company was created (see Fernow.)  Joel is not in this list. On August 9, 1776, Conklin marched a company of Ulster recruits to the "defence of New York" in anticipation of the invasion of New York City by the British. Indeed, the British landed in Brooklyn on August 27th. The surviving muster is shown below.  Conklin's company was in the regiment of Levi Pawling (spelled 'Paldens' on the muster). Pawling's (and Conklin's) role in the Battle for New York is not known, but it appears that Conklin's company was assigned to Fort Montgomery for this period and did not experience any action.  Josiah Terwilliger stated he was in Conklin's company on a 4-month enlistment, and that they were at Fort Montgomery from September until December 1776 and saw no action. Interestingly, Terwilleger does not appear on the muster, indicating that additional recruits may have been enlisted at a later date than August.

August 9, 1776 muster of Conklin company of levies in the regiment of Levi Pawling. Click here to view larger image.

With the fall of New York City in 1776, improvement of the Highland Forts (Constitution, Clinton, Montgomery) proceeded with urgency. Conklin's militia company was drafted for much of this work in the Spring and Fall of 1777.  On "last of April or first of May", Abraham Masten enlisted for four months as corporal under Captain Conklin and was "employed in erecting that fort [Montgomery]" under the command of Colonel Dubois [of the 5th New York] and Lt Col Jacobus Brown [Bruyn?] with Colonel James Clinton in command.  He thought his term expired "first of September." This agrees with the pension deposition of Harmanus Terwilliger who was at Fort Montgomery for 5 months in "Conklin's regt" then two at Fort Clinton with Captain Rose. Robert Aldrich (Aldredge), from Marlborough, was also at Fort Montgomery in Conklin's company for a two-week stint and then "drafted" for four months where he "worked hard at drawing stones, cutting sod, and facines."  He was drafted for another 3 months "but Ft Montgomery was taken and he did not go."

Conklin's whereabouts on the tragic loss of the Highland Forts on October 6, 1777 is presumed to have been with the bulk of Colonel Jonathan Hasbrouck's regiment deployed on Constitution Island. Constitution Island was not attacked on October 6th but was soon thereafter abandoned. [Only 11 of 277 prisoners of war from the battle were attributed to Hasbrouck's regiment. Two names match members of Conklin's company including 'John Snyder', who appeared in the May 4, 1778 muster and the April 1779 List of Exempts, and 'John Stephenson', who appeared in the August 1776 muster, but he was levied out of Smith's company.  Other surnames of prisoners from Hasbrouck's match common names in Conklin's regiment, but the given names do not match:  Ostrander, Lawrence, Terwilliger.]

Conklin's company was active in the recovery from the defeat of the Highland Forts, which included building structures at West Point and New Windsor (Nicoll's Point Redoubt near the Chevaux de Frise).  Private Andrew Willson stated in his pension deposition that he was on duty "between New Windsor and the highlands building forts" between November 1777 and January 1778. 

Conklin's officers were "certified" on March 9, 1778 "In the district or beat on the South east side of the Paltz [Wallkill] River."  They were enumerated as Jacob Conklin - Captain, Jacob Lawrence -1st Lieutenant, David Gue [Guion] - 2nd Lieutenant, and John Crowel - Ensign. These are the same officers named in a surviving muster of May 4th, 1778.  That muster includes Joshua Cammell, who is Joshua Campbell, Joel's son.

Members of Conklin's company served in 1778 "on the frontiers" protecting farms against marauding Indians. Joshua and Robert Aldredge (both enumerated in the May 1778 muster) served on the frontiers in 1778 under Captain William Cross. Typically, one third of a company would be required to march on one of these expeditions.  The captains in Hasbrouck's regiment would rotate leadership of these expeditions in a similar fashion.

In 1779, several of the members of Conklin's company served on the frontiers, sometimes under Conklin, sometimes under other regimental officers. Simon Terwilliger stated he was drafted for three months to serve on the frontiers under Captain Conklin. David Winfield stated that he served at "Peenpack near the Delaware River" in November 1779 as did Henry Crans (Croutz). Aaron Terwileger said he served "at Peenpack and other places served two or three months" in the fall of 1779. 1779 is also the year when Conklin included his own name on a List of Exempts in April.

1780 brought more service on the frontiers.  In March, a detachment was ordered to Mombaccus under command of Lt. Wygant that included members of Conklin's company.  Private Martin Wygant stated that he was also "on temporary duty" with another captain James Denton near Dewitts. David Winfield served at Shandaken in June.

The lore around Jacob Conklin was passed down through his family.  The stories below are from The Van Benochouten Family in America by William Henry Van Benochouten, State Library, Lansing, Michigan, p246 - 254, transcribed by Betty Kinzie.  Jacob was married to Catrina Van Benschoten

According to family lore, Jacob "... sat on many courts martials; and also served as Judge Advocate. He is said to have enjoyed the favor of Washington and to have dined with him on several occasions during the war."

One story is told that... "Once during the Revolutionary war when returning to his regiment after a short furlough his route led him through Newburgh. Reaching an inn on the outskirts of the village after dark he notice a number of horses tied to the fence surrounding it, and upon reconnoitering found that there was a gathering of Tories of that neighborhood within. Although alone he dashed into their midst with drawn sward, calling out to an imaginary squad, "Come on, come on, arrest these -------- Tories!" and had the satisfaction of seeing them all rush out at a rear door, and as he sheathed his sword heard the clatter of their horses' feet as they dashed away at breakneck speed. He then went to bed and enjoyed a good night's rest." 

It is family tradition that ... "one day when Capt. Conklin was out on a scout with his company, as they approached a bluff of land overlooking some stream on the western frontier, they suddenly came on a large force of Indians down below intent on torturing a white prisoner. They had stripped him naked, pierced him full of fat-pine splinter, and were in the act of leading him around a great fire preparing to burn him at the stake. The situation was critical, for the Indians outnumbered his force five to one; but the captain's spirit rose higher and higher as he gazed at the cruel sight. Finally, motioning his men to retire quietly, he ordered them to examine their priming with care, and on advancing to aim with exactness and fire at a sign from him. The Indians were startled, many wounded, some killed. To be brief, these tactics were followed for three volleys, withdrawing to load and advancing to the brink of the bluff to fire. Then the whites charged down upon the savages. It was thenceforth a terrific hand-to-hand encounter. It ended by the Indians breaking and fleeing. Conklin had torn off his lace and finery, thrown away his hat, tied a handkerchief about his head to as to conceal his rank, and came off unscathed. As soon as the Indians fled the captain ordered their canoes, which they had buried in the sand for concealment, dug up and launched that his party may might get away as early as possible. Waiting for three of his missing men took time, - precious time; finally they appeared, two supporting a wounded third. Instantly these were aboard they shoved off and made downstream, - and none too soon, for in a few moments Indians swarmed on the late battleground and vented their rage in yell after yell at the escape of the white men."

Sadly, there are no tales of Conklin's exploits in the Canada expedition of 1775, the Battle for New York of 1776, or the Battle of the Highlands in 1777.

Supposedly, the well-educated Captain moved to New York City after his wife died where he taught school. In 1805, he purchased two hundred acres of land at Sempronius, Cayuga County, where he died in 1813.

Happy 290th Birthday!

If we believe the majority of genealogies on the internet, then today is Joel Campbell's 290th birthday. According to most 'genealogists' he was born on January 22, 1735. (If you have read my book, you know that I am skeptical.)

There are no birth, death, or marriage certificates for Joel; no (contemporary) church records; no diary.  The date may be inaccurate, but evidence of his life in this period exists on one map, one deed, one militia muster, tax assessments, store ledgers, and census records. 

He was born a 3rd generation American in the City of New Ark, a community established in the British Colony of New Jersey by Congregationalists from Connecticut and Long Island. How Joel's grandfather joined this insular community without being related to its founding members is still a mystery.

In 2035, we will celebrate his 300th birthday.  Three hundred years does not seem like such a long time when one considers the age of the earth or the time since the last ice age. But it is enough time for just about everything to be forgotten. Did Joel have any desire to be remembered? I hope he is not offended that I am celebrating.

Did Joel think about the distant future?  Probably no more than we do.  Joel could not have envisioned a time when people traveled in steel machines and not on horses, where people wrote on screens and not on paper, where there were more salesmen than farmers, where people lived comfortably on small lots with no livestock.

Will anyone celebrate Joel's 500th birthday, two hundred years from now? It will be 2235. Will it be a time of unprecedented prosperity or a time of struggle for survival after a cataclysmic event? Will the human race predominate or will super-intelligent robots rule? Will history be more accessible or will there be a dark age after an electromagnetic pulse makes access to a totally digital history nearly impossible to retrieve? Perhaps mankind will have left for another planet where time is no longer measured in earth-years, making a 500th birthday a bit confusing to generations born on the new planet?

Today, I will celebrate the present.  I am lighting 290 candles for Joel.

Exempts in Conklin's Company of Ulster Militia in April 1779

On April 23, 1779, Captain Jacob Conklin published "A Exempt List" for his company. It contained 28 names including Joel Campbell.  This could have referred to the father who was 44 years old or his son, also Joel, who was about 24.

Photo of the original document by the author.  I believe the document resides at The George Washington Headquarters Museum in Newburgh.

There was a companion document at the GWHQ Museum that I believe is related to this one.  One side contains Captain Conklin's name and the amount of £104, the exact same total as on the List of Exempts.  On the reverse is a title transcribed as "Taken by of Cl[a?]ssors? for the Said Precenct", followed by seven names of prominent citizens, presumed to have collected the Exempt Fee from those on the Exempt List (see below).

Photo of Conklin receipt by the author.

Photo of reverse of Conklin receipt by the author.

The New York Militia   Throughout the entire Revolutionary War, all men between the

ages of sixteen and fifty were subject to compulsory militia service. Militia service usually was for short periods of time within the locality of the militiaman whereas "continental" service (George Washington's army) was generally for a longer period and could be anywhere in the colonies. Both Joel and his son, Joel, were subject to militia service.

"Classes" in the Militia  When it became necessary to engage the militia for periods of longer than a week at locations farther from their home, it became the practice to only require one third of each company to march. The remaining two thirds stayed behind to protect the community and run the farms and businesses that in many cases were feeding, clothing, or arming the continental forces. To facilitate this, "classes" of three persons were often formed, with one of the three marching and the other two remaining.  The person in the class who marched was normally compensated by the other two. It appears that officers also formed classes, resulting in expedition companies that were a mixture of militiamen from several different home companies. The second document indicates the payments made by the Exempts were connected with "Classes." Joel may have been part of a class where the payment was not to the serving soldier, but to the Precinct officials?

Exemption from Militia Service  Several militia laws were passed by New York during the Revolution. All of them fine-tuned the qualifications for "exemption." By the end of the War, the exemption qualification became so general that it included all those "engaged or employed in any Manufacture or Business, so that it would be for the Good of the Public..." and subject to approval of the Commander in Chief of the New York Militia (the Governor). Explicitly exempt (often with stipulations) were Quakers (religious), "Lieutenant Governor, the members of the State Senate and Assembly, their several clerks, the Secretary of State, the Attorney General, the Auditor General, the State Treasurer, judicial officers and their clerks as well as sheriffs and county clerks," sheriff's deputies, gaolers(jailers), coroners, ministers, doctors, ferrymen, millers, schoolmasters, essential war workers (makers of arms, powder, clothing ... including "Wood Cutters, Blacksmiths, Coopers, Colliers & Carpenters.") [see Alexander, Arthur J. “EXEMPTION FROM MILITIA SERVICE IN NEW YORK STATE DURING THE REVOLUTIONARY WAR.” New York History, vol. 27, no. 2, 1946, pp. 204–12.]  Exempted individuals were assessed a fee in lieu of service. For Quakers the fee was £10 in 1777. The list of exempted occupations would suggest Joel had a trade, but the 1793 deed describes him as a yeoman.

Summary  Included in the List of Exempts is Captain Conklin and all of his commissioned officers. This seems a bit odd to me unless the exemption is due to service in a recent expedition and not to some civic responsibility at home.  If the latter were the case, why were they ever selected as officers?  If the former is the case, could that also be the reason for exemption of others on the list, including Joel? No service records for Joel or Conklin's company in the winter of 1778-79 have been found.

Residence in 1779  The members of Conklin's company were generally from western Newburgh. Twelve of the 28 exempts were signers of the Newburgh Pledge of 1775. [See Ruttenber's HISTORY OF NEWBURGH]. One was a signer of the New Marlborough Pledge. [See Bond's HISTORY OF MARLBOROUGH]. Joel was living further east than his residence in the 1790 census of Montgomery.

Net Worth in 1779 Of the 28 Exempts, Joel and 4 others were assessed the lowest amount of £1 4. If the fee was assessed in proportion to net worth, then Joel was on the low end.  The highest assessed person was Henry W. Kipp at £20.