Air compressor?

[Saghost]

Just like my air scrambler road rammer from the 1980’s? Let me guess reference is Wikipedia? If you believe that I have an orange bridge for sale in a prime location.

Do you have any idea the amount of pressure that would require to have any meaningful boost? Also air due to its high oxygen content wouldn’t work. Possibly could use Nitrogen but still the energy to compress it and amount of pressure would be astronomical, bio jet fuel would be a better option. And for all you non-Gullible non-millennials here you go, good luck getting the jingle out of your head.
View attachment 487138

What does oxygen content have to do with anything? We aren’t talking about combustion, just pressure and movement.

You don’t need much pressure - 30 psi gauge is enough to push air to sonic velocity at the choke point. You do need a lot of volume and a suitable nozzle design.

 

[coleAK]

Portal axel

So how did these wranglers and land cruisers get air to the wheels?

It’s fairly common Up here in Alaska on Tundra rigs and Arctic trucks running 44’s. Most of them are external like the inserted picture. One of the guys is sitting behind me at work and has custom dana axels with airtight hubs on a wrangler. Check out “arctic trucks” they do mostly Land cruisers, Helux, tacos, and sprinters.
Arctic Trucks – Explore Without Limits

 

[coleAK]

What does oxygen content have to do with anything? We aren’t talking about combustion, just pressure and movement.

You don’t need much pressure - 30 psi gauge is enough to push air to sonic velocity at the choke point. You do need a lot of volume and a suitable nozzle design.

With the oxygen in the air It’s not the combustion. It’s the temperature change of quickly expelling compressed air. Expel it too quickly and you get water which blocks the intended air flow. Why long Use extremely high pressure tools and competitive air rifles use compressed nitrogen. And remember you are talking about pushing a 3k lb car. I can see using some type of air jets to fill the turbulence void behind the extremely aerodynamic roadster going very fast but the boost it would take to actually push is crazy.

 

[Saghost]

View attachment 487246 Portal axel

It’s fairly common Up here in Alaska on Tundra rigs and Arctic trucks running 44’s. Most of them are external like the inserted picture. One of the guys is sitting behind me at work and has custom dana axels with airtight hubs on a wrangler. Check out “arctic trucks” they do mostly Land cruisers, Helux, tacos, and sprinters.
Arctic Trucks – Explore Without Limits

Interesting. So they took a typical body mounted 4 at a time inflation system and added a roller coming out of the outside of the axle and left it all hanging out in the breeze.

Okay, I'll concede it is possible to build a CTIS system without portal axles. Not one I'd consider a good, reliable, or even a safe system, but a functional system. Portal axles let you run it down the inside of the axle, protecting everything and avoiding weird lines sticking out the side of the car waiting for rocks or branches.

 

[Saghost]

With the oxygen in the air It’s not the combustion. It’s the temperature change of quickly expelling compressed air. Expel it too quickly and you get water which blocks the intended air flow. Why long Use extremely high pressure tools and competitive air rifles use compressed nitrogen. And remember you are talking about pushing a 3k lb car. I can see using some type of air jets to fill the turbulence void behind the extremely aerodynamic roadster going very fast but the boost it would take to actually push is crazy.

Huh? I assure you that no amount of freezing oxygen will result in water or ice. You'd need to have hydrogen to react with it, and that's not a low temperature reaction nor is much hydrogen in the air around you.

Moisture - water that's already in the air in gaseous form - is a valid point, and something Elon's team will have to address. But nothing to do with the presence of oxygen.

Yeah, the amount of thrust involved to see a significant change makes me wonder - and I also wonder about what the government will say about blasting the car behind you with the high energy air stream, especially if it kicks up rocks and the like.

I didn't say it was a great plan to make a huge difference in performance - just that it is the only way to make a car like the Roadster accelerate quicker than the base roadster will, and that Elon has promised they're going to do it.

 

[JBee]

Maybe using air thrusters to force the car downwards to provide more tyre grip would be the way to go?

 

[coleAK]

Huh? I assure you that no amount of freezing oxygen will result in water or ice. You'd need to have hydrogen to react with it, and that's not a low temperature reaction nor is much hydrogen in the air around you.

Moisture - water that's already in the air in gaseous form - is a valid point, and something Elon's team will have to address. But nothing to do with the presence of oxygen.

Yeah, the amount of thrust involved to see a significant change makes me wonder - and I also wonder about what the government will say about blasting the car behind you with the high energy air stream, especially if it kicks up rocks and the like.

I didn't say it was a great plan to make a huge difference in performance - just that it is the only way to make a car like the Roadster accelerate quicker than the base roadster will, and that Elon has promised they're going to do it.

F1 cars do 0-60 in <2 sec so with the correct tires is possible without air jets. @JBee. Ferrari have had various fans that helped with downforce and created negative pressures under the car so good theory.

 

[coleAK]

Huh? I assure you that no amount of freezing oxygen will result in water or ice. You'd need to have hydrogen to react with it, and that's not a low temperature reaction nor is much hydrogen in the air around you.

Moisture - water that's already in the air in gaseous form - is a valid point, and something Elon's team will have to address. But nothing to do with the presence of oxygen.

Yeah, the amount of thrust involved to see a significant change makes me wonder - and I also wonder about what the government will say about blasting the car behind you with the high energy air stream, especially if it kicks up rocks and the like.

I didn't say it was a great plan to make a huge difference in performance - just that it is the only way to make a car like the Roadster accelerate quicker than the base roadster will, and that Elon has promised they're going to do it.

you get condensation from the change in temperature from compressed to uncompressed due to the water vapor in the Air. Using a tank of pure oxygen is out of the question so pure nitrogen is the sensible choice for a clean (water free) compressed “air like” gas.

 

[Saghost]

F1 cars do 0-60 in <2 sec so with the correct tires is possible without air jets. @JBee. Ferrari have had various fans that helped with downforce and created negative pressures under the car so good theory.

Yup. But F1 tires aren't street legal - and would be a disaster in the rain if they were. On prepared strips, nitro driven funny car drag racers get truly insane acceleration with really sticky rubber. But that's not something you can put on the street. As I said "the best tires you're allowed to have..."

 

[coleAK]

Yup. But F1 tires aren't street legal - and would be a disaster in the rain if they were. On prepared strips, nitro driven funny car drag racers get truly insane acceleration with really sticky rubber. But that's not something you can put on the street. As I said "the best tires you're allowed to have..."

I wasn’t saying it was fully possible but not outside reality. Also the roadster is AWD and F1s are RWD. Rimac C-2 is AWD and did 0-60 in 1.85 on street tires without air jets.

 

[Saghost]

Maybe using air thrusters to force the car downwards to provide more tyre grip would be the way to go?

Actually, with unlimited power it probably would be. Modern sports car tires on decent normal roads give a peak of 1.4-1.5g acceleration I believe - so if you have unlimited torque, you get ~50% more acceleration out of providing downforce than pushing back, and it avoids the whole "your thrusters threw rocks at my windshield" situation (unless the rocks were sitting in the upwards facing nozzles to begin with somehow...)

 

[JBee]

The other thing is that at speed you can create downforce through the air slipstream. So downwards thrusters would only be required up to a certain speed where airfoils would provide downforce instead.

I'd imagine that the same would apply to sideways acceleration through corners, where thrusters on the inside of the corner would provide extra grip and provide a load shift where the inside tyre can be loaded more.

In saying all of this though I'd imagine that a simple low pressure high flow fan, along with a smooth underbody with low ground clearance (or possibly a retractable skirt) would work better and use less energy. Technically reversing that system could provide lower rolling resistance, and maybe positively influence airflow by lifting the vehicle on a partial air cushion. Of course the system would be able to react to a breaking event instantly, and would also improve braking times through extra grip creation.

 

[JBee]

Something like this T.50 should work. I'm wondering if the CT would also benefit from some active aero to keep things laminar? It doesn't seem particularly complicated to do, and you wouldn't have to do it to the same extent as a supercar.

With the thrusters, i'd expect they'd work best when placed at the front of the car.

I also wonder if a swashplate type compressor like the A/C compressor will be used for pressurized air on the CT, if they use a larger compressor unit then just something they need for the air suspension. I'm thinking they could use the same compressor electric motor setup to achieve that and just configure each compressor for their purpose. So at a minimum use the same motor/speedcontroller, and potentially even switch the air compressor on via a electric clutch. Would reduce the parts that way.

Another option would be to have a variable stroke A/C and/or air compressor. So you'd just vary the angle of the swashplate on each to vary the output of each as required, but use a single larger electric motor to power both. No clutches required. You could also technically use some compressed air stored to drive the A/C if you wanted to.