Don’t trade on this blog post as 4 billion years of evolution is against it and even God himself.
Look at $TM monthly sales patterns.
I looked into seasonal patterns of $TM in the US market as a measuring stick.
The data was for every month in 3 years, 2016-2018.
The goal was to see how the numbers of cars sold in two first months of a quarter are to the third and final month multiplied by 2. I called this ratio the “Sales Effort”
I created a measure of demand which I called “Organic Demand”; the sum of the first two months of a quarter. If the “Sale Effort” is one or near then we have perfect “Organic Demand”, otherwise companies need to incentivize or push for sales.
I can see seasonal patterns; “Organic Demand” in Q1 is low and in Q3 high.
“Sales Effort” reverse pattern; Q3 low and Q1 high.
Data points to the following pattern.
“Organic Demand” steady, seasonal small change, a top average of 3 years (Q3) = 435k, 129% of low Q1.
“Sales Effort” steady, seasonal small changes, average Q1 (high) = 337k, 130% of low Q3.
$TSLA Sales Pattern after Starting from Q1 2019.
Q4 2018 was the last quarter where $TSLA was fulfilling preorders (production constrained). Since Q1 2019 $TSLA has been demand constrained or assumed to be since the number of sold cars in the US per quarter reached a peak in Q4 2018. The delivery lead time might serve as a good indication of that assumption. When comparing the patterns of $TSLA and $TM we have to keep in mind that $TM has a network of dealers that smooth out the variations in demand and production. I hope that the statistics capture the final demand with some reasonable fidelity so that we can venture to make somewhat valid comparisons and conclusions of the current state of $TSLA demand.
In this plot, I encluded Q4 2018 results and software applied trend line polynomial 3 degrees. The trendlines capture the periodic character of limited data, but at the end of the plot incorrectly anticipate a severe decline of values plotted. Also, the Q1 2020 is just a copy of Q1 2019 data.
Our attention should be directed at Q1 2019 to Q4 2019. In general, Q1 is seasonally a poor quarter, Q3 is the best. This pattern is maintained here (validation?). “Organic Demand” for Q3 is 203% of Q1. This was 130% for $TM. “Sale Effort” in Q3 is the lowest 93% of Q1 but in Q4 it becomes to be 270% of Q1. It seems $TSLA starts with organic demand and keeps selling Models M3 with the same “Sales Effort” it had in Q4 2018 when it had been delivering to preorder holders (production constrained) then in Q4 2019 the “Organic Demand” deteriorates (-20%) and the quarter numbers are made up in the 3rd month which presupposes incentives or aggressive marketing. For $TM this drop would be within the bonds of full seasonal change.
Is the Model 3 demand declining as this would suggest? The introduction of Model Y which is basically just Model 3 Hatchback (The year 2020 model?) might be a better clue.
Since there will be no more monthly data in the US that allows insight into the guts of demand or possible extent of “Sales Effort” companies put into “making” quarters let’s do the EU tomorrow!
Do not trade this blog since 4 billion years of evolution is against my judgment and maybe God himself too!
What remains of demand for $TSLA Model 3 after the rush of virtue signaling subsides? The answer is the organic demand, scratch a bit deeper, not much!
Neither the US or the EU are homogenous markets but the differences within the EU are much more pronounced, or easier to document than in the US.
The plots represent data collected by @fly4dat twitter post including a spreadsheet with data on EU countries. I only replotted this data, so that you can with a glance visualize the decline or assent of the demand in a given country.
The data covers with some uncertainty the partial data in Q1 2020, otherwise, the rest is actual numbers.
The EU overall;
$TSLA moves from one market to another, once the V-S demand is gone and what left is the organic demand it pours its cars in the next target preserving the perception of at least constant demand. Examples follow.
The Catastrophe – Norway
France, not yet New Hope!
Is this the New Hope or the Last Kick in the Pants?
Is this the New Hope dud?
$TSLA pursuits throng of the demand minnows in the EU, all mostly under 1000 cars/ month. I left out some markets above that, but now $TSLA is picking pennies of a demand.
Just the same for the US market.
Nothing on Q1 2020 from $TSLA yet. It seems that the Great $TSLA Demand Hoax will only be put to death but a thousand cuts, it will just bleed to death the Longs along with Elon, or Federal gov. will save for few quarters the “jobs” of $TSLA workers. These are just transfers from the investors, and anybody involved, to the buyers and workers. If you think otherwise you are a Marxist.
Don’t trade on this blog since 4 billion years of evolution are against my judgment and maybe even God himself.
So we play with numbers here first then we make some conclusion.
Empty Starship we are told weighs about 120,000 kg. At 200 miles orbit, this translates into 30,175,000 Joule/kg (kinetic energy per kilogram). You have to dissipate this energy on re-entry into the atmosphere and things get hot and violent. For 30 minute descent, this translates into heating and compression air 557,112 horsepower machine (for full 30 minutes).
So there is the ballistic factor:
You cannot change the W=weight
But you can change the A=area resisting the flow, and together with
The Coefficient of Drag=Cd, by maneuvering the Starship during reentry.
There is another measure involved which is Cl=Coeefficient of Lift, as a body goes through the atmosphere it produces lift together with drag (or if it is a ball Cl=0). Starship is designed to produce lift so Cl is not zero. L/D ratio relates Lift to Drag. If Lift is larger than zero the reentry can be spread in time.
The Ballistic Factor ratio of the kinetic energy to the innate ability to convert it into heating of air by compression and friction.
The Ballistic Factor for Starship can go from 205kg/m2 just hitting air sideways to 8000 kg/m2 going the cone first. The coefficient of Drag respectively from Cd=1.5 to .3. The coefficient of Lift Cl=0 to .8. (all numbers estimates, and approximations to show the possible ranges, not precise values)
So what is the gamble quoted in the title? Let’s see a graph;
As Starship enters the atmosphere at 120km above Earth the air is so thin that it flows over the ship like water from your faucet producing a clear orderly column of water, before you open it up so that it becomes turbulent (mixing) – it is called laminar flow. The surface of the ship heats up from the friction of the air, in the greatest proportion to overall dissipated energy. As the density of air rises and velocity drops a lesser fraction of the energy goes into spacecraft, but the overall amount of energy is dissipated grows so that the rate at which the heat flows into the spacecraft skin does not drop precipitously. At 30km the frictional heating and compression of air become so intense that besides convection the surface heats up due to radiative heat, as the air surrounding the ship heats up to thousands of degrees. The energy radiated toward the ship is proportional to the fourth power of the absolute temperature of the air. As air dencity increases and velocity drops further, there is appearing turbulent convection (transfer of heat when there is a contact of the fluid with solid) besides radiative heating.
Elon’s gamble is to maneuver (change A, Cd, and Cl) the Starship so that heating rate (a critical parameter) can be controlled and spread over time as well as the dominant type of heat transfer, with radiative heat transfer being most advantages because Starship cladding is made from stainless steel polished to reflect at least 90% of the radiative heat.
The above graph shows the results of optimization to strike a balance between structural capabilities and limits on heat transfer. Elon’s gamble is to move beyond that and aggressively manage the velocity of reentry and by extension the heat transfer rate to the ship, by leveraging the reflective surface of stainless steel Starship. This might be much more complicated and daring than it seems. The descent engines and the movable surfaces are available to achieve this. This has never been tested.
Structurally, Starship aimed at integrating the fuel tanks into the shell. There was also a change in material from ANSI 316L to 304L which is unclear why since both are low carbon (since L(ow)) versions of 316 and 304 respectively. The cryogenic test failed as stainless steel might experience corrosion in welds and that depends mostly on carbon content. Liquid oxygen is not a forgiving fuel to store as over certain pressure the stainless tank might ignite. (over 1000lbf/in2). The structural issue lingers since many aerospace material are lighter and more suitable with greater strength to weight ratios than stainless. Eleven % of the Space Shuttle weight was dedicated to ceramic tiles. That was 8,600 kg out of 78,000 kg. The stainless steel cladding, if 3mm single layer thick, weighs about 34,000kg out of 120,000kg estimated Starship weight (28%). There seems to be a stainless steel weight penalty. Will its benefits outweigh the cumbersome process to which was subject the Space Shuttle? Add on top of this the fuel penalty since you take this mass up and then land the Starship just like the other SpaceX rockets.
I am not able to run a detailed analysis, but all I see are weight penalties traded for an idea of getting rid of ceramic tile insulation, at least at this stage of design. The idea can fail altogether or can pass (not likely) the test of reentry but the weight penalties can be such that it might be equally, or even more, unprofitable as the idea of landing the booster stages of rockets on ships.
Let’s put it into narrative.
The Space Shuttle had aerospace alloy + composites (if am correct) construction and used ceramic tiles to protect the craft from reentry heating.
The tiles were causing maintenance and reliability problems, but allowed to lower structural weight of the craft. The problems with the tiles basically defeated the concept of reusable craft. One mission was lost due to their failure.
Elon is constantly looking to beat the paradigm of space travel and picks following strategy.
Get rid of tiles, and use mirror (as close as possible) stainless steel to reflect off radiative heat of reentry.
Provide the Starship with lift capability to extend the reentry time and control the amount of heat absorbed.
Allow the Starship to increase its ability to change ballistic factor by change in Area and Cd, all by maneuvering but this is limited by the maximum deceleration forces.
Maneuvering allows control of velocity at given density of air so that desired heat transfer regime can be extended. Mirror finish might reflect 90% radiative heat.
Passive controls by low heat conductivity of stainless steel, and possibly second stainless skin.
Under this scenario reentry becomes complex and dynamic maneuvering procedure with larger g forces on the frame and crew (possibly at times). Also heating becomes complex and dynamic due to maneuvering, not to mention heating stresses due to temperature differences.
Now, let’s turn our attention to structural weight problems and their tried solutions.
Use of the cavity enclosed by the skin as structurally integrated fuel tank. Cryogenic test failed probably due to field welds quality. Other issue is the weld chemical corrosion besides just quality issues.
If indeed fuel tanks would be integral and exposed to directly absorb heat energy upon reentry the pressure in them can rise toward catastrophic failure. (Playing devils advocate)
If the idea of integral tanks to survive we can not dismiss the possibility of second skin (3mm thick?) to isolate them from reentry heat.
Non stainless steel internal tanks might the best solution here. Increased weight though.
The weight of single 3mm thick skin layer is about 34 tons. This is 28% of the 120 ton empty weight. For the Space Shuttle the weight for all the tiles was just 11% of empty weight of ~75 tons. Add second skin?
Assessment of stainless steel as structural material is rather to disadvantage of stainless steel. Light aerospace type aluminum alloys beat stainless with 4 time that strength per unit of weight. Stainless is either chosen for corrosion resistance, for forming, esthetics, and low thermal conductivity (but not refractory or high temperature applications).
To eliminate tiles and its shortcomings stainless steel and the above reentry method is chosen.
The solution using stainless steel has weight penalty and increases complexity and risk
The struggle to lower weight of the Starship and manufacturing shortcomings of #SpaceX lead to structural test failures.
The goal of making rapid turnover between launches spaceship seems to be defeated by excessive structural weight as it imposes economy penalty vs. other methods, even if complex maneuvering during reentry will be successful.
Every pound of structure requires some amount of extra fuel to be lifted into the orbit. This phenomenon has doomed the efficiency of reusable lift rocket.
The Starship can fail in few ways.
Failure of the concept of maneuverable reentry, by way of structurally failure due large aerodynamic forces, by excessive heating of spaceship. These can quite complex.
The structural weight penalty making the Starship not economical
The attempts to lower structural weight of the Starship can expose it to structural failure.
Manufacturing methods are already exposing the craft design to failure.
One very ugly remark on the Starship; I does not look elegant as a solution to engineering problem, it look downright UGLY. You know engineers have intuition too!
I created two metrics to describe the demand situation in NY. The first is “Organic Demand”. I know that this is a lame idea but for a lack of a better one, I assumed that at my level of intelligence it suffices. The idea goes that the “Organic Demand” can be measured by the 2 front months of the quarter, and it is relative to other quarters and the final 3rd month of the quarter. The ratio of 3rd Month to 2 Front Months I called “Sales Effort”.
The Q4 of 2018 is the last Q when $TSLA was filling preorders. The green bar for 2 Front Months is larger than for 3rd Month (Yellow). This is the yardstick of “Full Demand”. The other special case is the seasonal pattern for Q1 of 2019 and Q1 2020. Since there is no data for March 2020 (3rd month) I assumed that 473 Model 3 just like in Q1 2019 are registered, and hinting at 18% larger “Sales Effort” than of Q1 2019.
The trend for “Organic Demand” is down.
The trend for “Sales Effort” is up.
The trend for the 3rd Month is more or less flat.
Notice that “Sales Effort” in Q3 2019 is as slightly larger than in Q1 2019, the collapse of demand after year-end and fulfilling preorders.
This graph can be validated or disproved by the March 2020 data.
From the registration data in New York, one can see numbers hinting at the depletion of organic demand and the increasing efforts of the company to keep the sales numbers steady (NO GROWTH!).