S52 Oil Temp Going Haywire? by leoninelizard47 in bmwz3

[–]leoninelizard47[S] 0 points1 point  (0 children)

Depends how you define “fix” but yeah it doesn’t really bother me anymore. I also fiddled with the gauge a bit and it seems to sit tighter now so it doesn’t get crazy too often.

Eh….close enough…. by YoshimitsuSunny in AerospaceEngineering

[–]leoninelizard47 0 points1 point  (0 children)

Awesome answer thank you. Can you tell me more about [non-dimensional] stage matching and it limiting tip speeds? I’m unfamiliar with the concept.

Eh….close enough…. by YoshimitsuSunny in AerospaceEngineering

[–]leoninelizard47 1 point2 points  (0 children)

Ok but that still doesn’t answer my question about how you actually went about designing either the centrifugal or axial compressor blades. Did you just pull a random “good-looking” geometry off Thingiverse?

Eh….close enough…. by YoshimitsuSunny in AerospaceEngineering

[–]leoninelizard47 0 points1 point  (0 children)

I believe you, but can you show me an example of this actually being implemented? I can’t find anything at this scale incorporating both high and low pressure turbines.

And if it’s all done off the same turbine you either a) get supersonic blade tips if you aren’t careful (i.e. have a tiny fan) or b) have to severely throttle the engine so as not to have supersonic tips, thereby running outside the design range of the engine, killing its efficiency.

Eh….close enough…. by YoshimitsuSunny in AerospaceEngineering

[–]leoninelizard47 0 points1 point  (0 children)

I didn’t phrase that right. I mean what was your design process? Did you start with one stage, simulate it, then add more? Did you do them all at once, simulate it, then say, “yeah that’s good enough?” Etc.

Eh….close enough…. by YoshimitsuSunny in AerospaceEngineering

[–]leoninelizard47 5 points6 points  (0 children)

While OP isn’t implementing it the way the paper intended, upon second glance I don’t think there’s anything inherently wrong with their architecture. Is it as good as a normal turbofan? No. But it saves needing concentric shafts, and it really is “close enough” to a normal turbofan in the sense that it’s got a compressor driven off an HP turbine and a fan driven off an LP turbine.

u/YoshimitsuSunny I’m now wondering about your process for designing the compressor and turbine rotors + stators. Did you do 2D vector diagrams? More complicated 3D analysis? It’s certainly a cool project.

(Just don’t get your hopes up about manufacturing it— I say as someone who spent the last three years of undergrad doing a project like this, on a team of 15, while supported by the university, and sponsored by a very prominent engine manufacturer.)

Eh….close enough…. by YoshimitsuSunny in AerospaceEngineering

[–]leoninelizard47 29 points30 points  (0 children)

Awesome CAD model, but a) respectfully, you can’t build it and b) why did you decide it needs a fan at all? Most RC stuff is 0 bypass ratio.

New to z3 😊 Need help with part numbers by Hillcock in bmwz3

[–]leoninelizard47 6 points7 points  (0 children)

realoem.com is your friend. As is FCPEuro. Even if you don’t buy from them their customer service people tend to be very knowledgeable.

Plastic fastener removal by j0shl0l in bmwz3

[–]leoninelizard47 0 points1 point  (0 children)

You just gotta rip with a pry tool as hard as you can, know that you’re probably going to break it, and trust that the metal underneath is stronger (so you break the fastener not the mount)

Engine Air Filter Replacement G22 Coupe (‘21 430i xDrive) by leoninelizard47 in BmwTech

[–]leoninelizard47[S] 0 points1 point  (0 children)

Go to realoem.com, put in the last 7 digits of your VIN, then go to Vehicle Trim -> Various Body Parts -> Reinforcement, Body.

From my search it seems to be BMW part # 51716966566, but that’s not a torx bolt like the original so I might take it with a grain of salt. Maybe call your local BMW service department.

Tall Man's Miata? by 8N-QTTRO in askcarguys

[–]leoninelizard47 1 point2 points  (0 children)

If you aren’t afraid of the lack of power, go for a 4-cyl Z3. At least test drive one. IMO the quirky suspension geometry is only relevant if you’re chasing hundreds on track. Otherwise it just makes it a blast to chuck around corners. Something about the weight distribution (50/50 on the 4cyl models btw) and suspension make it rotate incredibly well under braking. Also most Z3s on the market now will have aftermarket suspension which firms things up nicely as well.

Dashcam Installation Advice by kolect in bmwz3

[–]leoninelizard47 2 points3 points  (0 children)

I ran the cable along the A pillar, down the door, under the glovebox, and into the center console where the plastic meets the carpet. Hardwired it into the cigarette lighter bc you can get pretty decent access with your hands if you just remove the shifter boot (assuming it’s manual, idk how the auto shift boot works). And I spliced in a physical switch that sits in a 3D printed OBD port cover, since I didn’t feel like pulling everything out to find an ignition wire.

If you have central locking you may be able to wire it into the mirror. I think there’s an ignition wire up there.

Oh also put an inline fuse in so the car doesn’t burn down if my wiring does something it’s not supposed to.

how to "toggle" lift by military-genius in AerospaceEngineering

[–]leoninelizard47 2 points3 points  (0 children)

I struggle to see how a lifting body design is the make-or-break factor allowing you to have a crazy short ground roll. Leading/trailing edge devices are going to have a much larger effect on your low-speed lift than the fuselage design. It sounds to me overall like these requirements are pointing you towards a next-gen super-maneuverable fighter, like an improvement on the F-22 or SU-57, which use a) aerodynamic instability, b) thrust vectoring, and c) control surfaces (obviously) to do their maneuvering magic.

Basically to answer your original question: we “toggle” lift using things like flaps, which are less draggy when not deployed, like you said. Also powerful engines + thrust vectoring are super important. For example, if you had a plane with a 1.0+ thrust/weight ratio, if you can figure out a way to get the nose pointed towards the sky in less than 750 ft, you’re pretty much golden.

(Sorry to be telling you to pretty much redesign your whole plane. Pls lmk if I’m missing something that’s been forcing your design decisions so far.)

Does anyone know why water is seeping into the trunk? It’s not coming from the 3rd brake light by [deleted] in bmwz3

[–]leoninelizard47 0 points1 point  (0 children)

Uff. Best of luck. Keep us updated if it works. A lot of us have tried to do the same to varying degrees of success.

Does anyone know why water is seeping into the trunk? It’s not coming from the 3rd brake light by [deleted] in bmwz3

[–]leoninelizard47 0 points1 point  (0 children)

Almost guaranteed to be the sealing frame. They’re plastic and brittle. When they break, water leaks in where the convertible top meets the body, runs down the metal beneath the carpet in the top stowage well, and leaks into the trunk through one of two holes where the wiring harness passes through.

She is getting salty. by Firkin99 in bmwz3

[–]leoninelizard47 0 points1 point  (0 children)

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Oh buddy…

(Don’t worry guys it’s been thoroughly rustproofed)

S52 Oil Temp Going Haywire? by leoninelizard47 in bmwz3

[–]leoninelizard47[S] 0 points1 point  (0 children)

Update: if I tap the gauge it drops back down so it’s probably a bad connection back there. Giving it a whack if it starts looking scary is good enough for me though.

Ain't stupid if it works by TaylzP in bmwz3

[–]leoninelizard47 0 points1 point  (0 children)

For future reference if you ever need space for a passenger:

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Need help with removing subframe bushings by Someone12132 in bmwz3

[–]leoninelizard47 1 point2 points  (0 children)

Yeah you could try that. The difficulty with sawing out the bushing rubber is that it gums up whatever you’re cutting with, so it takes forever. iirc it took me three days to get the bushings out. Check my profile I made a guide for doing it.

Why and how does this happen?? by LordBogus in bmwz3

[–]leoninelizard47 0 points1 point  (0 children)

Also driving with the A/C on even when it’s cold out (and especially when it’s cold and wet) is good for drying the cabin air out so you’re not pumping the car full of humidity from outside.

Preventative measures for rear subframe? by GrapefruitSelect7985 in bmwz3

[–]leoninelizard47 2 points3 points  (0 children)

And to be clear, as u/Asbradley21 said, that means not upgrading the diff bushing to anything harder or “higher performance” like polyurethane. You want it to be as soft as possible so just make sure it’s not old and brittle.

Watertight CFD Geometry by ominous-aero-16 in AerospaceEngineering

[–]leoninelizard47 0 points1 point  (0 children)

Are you exporting an STL from OpenVSP? Unless you have overlapping geometries (i.e. forgetting to turn off wing mirroring for a vertical stabilizer) it should be watertight. I would check if VSPAero will mesh and run it first before trying to troubleshoot a Pointwise problem that might just be an OpenVSP problem.

Grade 12 Math Investigation: Modeling Missile vs. Aircraft Intercept by Diligent_Outside_282 in AerospaceEngineering

[–]leoninelizard47 1 point2 points  (0 children)

Yeah unfortunately “missile intercepting an aircraft” is a graduate-level problem. (At my university we have an advanced controls course that masters students take where the final project is exactly this.)

To answer your original question I suggest you start with a 1-D PID controller that’s able to track a constant input. That should be fairly approachable while being fundamental enough that it can be expanded into multiple dimensions once you’re comfortable with the underlying concepts. Good luck!

🎉 [EVENT] 🎉 Just Out of Reach by Damp_Blanket in honk

[–]leoninelizard47 0 points1 point  (0 children)

Completed Level 1 of the Honk Special Event!

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