Today, landspeeders we look at!
Landspeeders belong to the “repulsorlift” transport class, like the podracers we looked at last year, and travel above a world’s surface (up to 2 meters) without contact (very useful on swampy lands like Dagobah). Landspeeders are the successors to the hanno speeder which was mainly used as a racing vehicle with many Tatooine natives still using them to race in the Boona Eve Classic today.
Landspeeders are found in both civilian and military applications but due to intergalactic ITAR regulations we will only cover the civil aspect here with a focus on the most famous of them all. If you want to know more about our experience working with military, defense and governmental organizations (whether you area part of the Empire, Rebels, Resistance or Separatists) feel free to contact us.
The Famous X-34
Luke Skywalker’s X-34, with its 6 selectable hover heights, features an engine consisting of 3 air-cooled thrust gas turbines able to reach a top speed of about 155 mph. The side engines are also used for steering although it is not obvious whether this steering is achieved by varying their thrust to be asymmetric or through vectoring of their exhaust. With the X-34 total length being 3.4 meters it helps us estimate the overall dimensions of its engines which are, each, roughly 80 cm long by 30 cm wide.
Zooming into Figure 2, the landspeeder engine seems to be a turbofan configuration with a single-stage bypass fan, 12-stage high pressure axial compressor, single-stage high-pressure and single-stage low-pressure turbine. Looking at our previous blog post on Redesigning Anakin Skywalker’s Podracer, we can do a comparison with Anakin’s original (before our redesign) podracer engine which was purely designed for racing. No afterburning for the landspeeder and no injectrine for the added speed boost.
Alright, let me nerd out for one paragraph (since clearly the rest of the blog was not nerdy enough). Overall, for similar vehicle dimensions, the X-34’s engine is about 10 times shorter, features a 15 times smaller outer diameter, has more rotating components in it and gives a top speed 4 times slower for a likely similar towing load. Not fully sure what the designer’s choices were here but let’s humor them. Using rough numbers taken from the table and Euler’s turbine equation, assuming that both vehicles operate with the same fuel, pressure ratio, firing temperature, efficiency and ambient conditions, we can estimate Luke’s landspeeder (over 3 engines) generates about 25% the amount of power that Ani’s podracer (2 engines) does. We can then estimate that the landspeeder’s engines would theoretically rotate about 35 times faster than the podracer’s if it is packing the same flow rate into the system (that’s with an internal flow cross-section area ~18 times smaller and recalculating the heat drop based on this area and power). We redesigned the podracer’s engine from last year to run at 17,700 rpm so that would make the landspeeder’s rotating speed roughly 600,000 rpm which is about 2 times faster than the fastest turbocharger. We could increase the flow rate to allow for a decrease in rotation speed but this comes at the cost of a higher diameter which would mean a new nacelle for the engines. Now, I wonder what kind of bearings these engines run on and how to cool them in that Tatooine heat? Let’s check to see if these parameters can result in an actual design or if the movies were more fiction than we originally thought. Using the Preliminary Design tool inside AxSTREAM®, I started from the turbine design file from last year, adjusted it to use the expected diameter and set out on the task of determining the flow rate, diameter and rotation speed that would give us the power we need (which comes to around 2920 kW since no afterburner was used in Ani’s podracer unlike in Sebulba’s).
Here come the numbers! The graphs below show the rotation speed in the vertical axis, the tip diameter (with the goal to be around 87 mm) on the horizontal axis, and the coloring of the dots corresponding to the power generated by the turbine. By now you might be wondering what all these dots actually are…oops, let me backtrack a bit and give you a short summary of our unique conceptual design tool. This tool allows you to generate thousands of different designs of a given machine type in minutes to evaluate (just like what we are doing here) what value is optimum for the different inputs that were specified as ranges. This way there is no guess work involved and you benefit from a massive save of time and increase in performance. So each of these dots corresponds to a different axial turbine that could be used in Luke’s engines. That’s about 25,000 geometries generated in less time than a coffee break.
Alright, back to the graphs. The first one (left) shows the full design space I created with powers ranging from very low (1.7 kW) to about twice what we need while featuring a tip diameter between 90 and 200 mm (again with the goal of being around 87mm) and rotation speeds from ~50k to 250krpm.
The second graph (right) filters out all the designs that are not within 10% of the desired power (that mostly was filtering combinations of flow rate and efficiencies that were out of the specs desired). Now this is where it gets interesting – there are no designs around the desired diameter… The smallest achievable diameter is around 145 mm.
Here is what one of the designs fitting the desired power requirements, with one of the smallest diameters possible (164 mm) and a relative low rotation speed (77.5 krpm) looks like. It has 2919 kW of power with a flow rate of 4.0 kg/s and a total-to-total efficiency of 88.2%.
This means that either
- The fuel used is different between the sporty podracer and the leisurely landspeeder. But that does not make a lot of sense here since the landspeeder’s fuel would have to be more energetic
- There are devices such as reheats being used in the X-34 although they are not portrayed on the cut-away figure
- The design looked good to the eyes of the average viewer so they called it a day
I know that for this I still considered the engine configuration to be a turbojet (from the podracer’s engine) and not a turbofan as per the technical figure but it should not make this big of a difference in power. One of the assumptions I took here as well was for both turbine stages to be at the same rotation speed but of course in practice you would design the fan and match the low-pressure turbine to it and design the high-pressure compressor with the matching turbine based on your cycle conditions.
After the death of his aunt and uncle, Luke sold his speeder in Mos Eisley to help pay for safe passage to Alderaan aboard the Millenium Falcom, blaming the newer model (the infamous “XP-38”) for the poor bargain of 2,000 credits (selling new for 10,550 credits and bought second-hand by Luke for 2,400) he got for it despite Lukes’s careful maintenance that allowed him to navigate the scorching heat of Tatooine.
Speaking of the heat, gas turbines are less efficient in hot climates due to the compression work being more energy consuming to provide the same pressure ratio. Given the 160F temperature on the surface of Tatooine it would be quite interesting to add devices to reduce the incoming air temperature. Such possible devices include inlet air fogger, pre-cooler, etc. all of which can be analyzed and designed with SoftInWay’s software platform.
Growing up, I remember hearing that for every 10 km/h of wind the felt temperature is 1C cooler so despite the presence of a full roof and if we consider the vehicle’s top speed we can conclude that it is still very hot in the cabin which is where HVACR comes in. Literature references a heating and cooling system but no actual information on it could be found. With the wide variety of weather conditions across the Star Wars universe, designing such a system can be tricky and it is even more crucial since its energy consumption should be taken into account for the design of the engines. Here again we have the tools to help you with this and even train you on how to become an intergalactic heat exchanger designer.
As a contrast to Tatooine, the subzero weather of Mando’s world would likely require an Anti-Icing System and a passenger heating system to safely and comfortably operate. In addition to the prevention of ice on the gas turbine blades and the comfort of the passengers, the weather also impacts the lubrication of the moving elements in the vehicle.
One could even presume that some landspeeders use custom fluids for lubrication as we saw Governor Tarkin identify the stain on Ensing Baz’s boot by the way it congealed as belonging to a T-44 landspeeder which was used in the early years after the Empire’s establishment. And that’s alright, our AxSTREAM.SPACE™ package comes with AxSTREAM Bearing™ which allows modeling any kind of lubrication fluid as long as there is a reference as to how it behaves.
Regarding fuels used for landspeeders, there are several mentions in literature (Rhydonium, Malastarian, and oil refined on Chewbacca’s homeworld of Kashyyk) although it is not clear which one(s) of these Luke was using to refuel his vehicle. Just like on Earth where fuel flexibility is important for some engines that are deployed in many and remote places that may not have prime quality gasoline, it is important to be able to adapt to the local resources. Nobody wants to be stuck on a planet after receiving your collectible Sy Snootles Signature Edition X-34 due to fuel incompatibility. Either way, a fuel pump can take many shapes and sizes that require careful design to ensure maximum performances.
Other Notable Landspeeders
Let’s take a look at a sample of other Landspeeders
Most landspeeder models were capable of carrying one or more passengers, and top speeds varied between 100 and 250 kilometers per hour with most models ranging from 3 to 8 meters in length.
The Flash Speeder (7.54 m long) shown below features an interesting concept where each of the two engines actually contains 3 mini gas turbines. Although I don’t see this being optimized from an aero-thermodynamics efficiency standpoint vs. a single, slightly bigger gas turbine, it leaves room for easy modularity to add more power to a vehicle and even disable some for student drivers.
The V-35 landspeeder (7.64 m long | top speed of 120 km/h) with its distinctive sharp leading edge was produced by the same company as Luke’s Landspeeder and is commonly found on Lothal shares similarities with the Flash Speeder in terms of the shape of the engines although it features 3 of them instead of 2. It is mostly used by the Resistance, is quite cheap and is mostly used as a courier to transport light cargo.
Speaking of Lothal, the RGC-18 landspeeder is also found there and made by the Soro Suub Corporation. But this 2-seater is fast and maneuverable (300 km/h | 6.26 m long) making it perfect for Vizago to move weapons around! We can note the design that looks very similar to Luke’s X-34.
Conclusions and Predicted Future of Landspeeders
Even though the cost of fuel on Earth has been plummeting lately, it is always a good idea to keep making more efficient vehicles so that their developing companies keep making profit even when the economy is not kind (who knows when a new Emperor will come to power). It would therefore be safe to say that hybrid and electric landspeeders may come to light in the coming years.
And on that note (queue Imperial March) feel free to leave a comment, reach out to us, provide suggestions for Star Wars related topics for us to look at next year and/or share this post with fellow nerds. May the 4th be with you!