Tesla truck, sharp edges and aero

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Cold Fussion
136
Joined: Sun Dec 19, 2010 3:51 am

Re: Tesla truck, sharp edges and aero

Post by Cold Fussion » Fri Nov 29, 2019 10:49 am

djos wrote:
Fri Nov 29, 2019 1:01 am
Brake Horse Power wrote:
Fri Nov 29, 2019 12:52 am
Didn't the Iraqiees take one down with a heat seaking missile?
Not a B2, no. Several F117’s have been lost in combat iirc.
Famously a F117 was shot down during the Balkans wars but from memory they were very lucky to actually shoot one down because they predicted its location based off previous bombing runs.

pb6797
1
Joined: Sat Sep 15, 2018 10:25 pm

Re: Tesla truck, sharp edges and aero

Post by pb6797 » Fri Nov 29, 2019 7:13 pm

PlatinumZealot wrote:
Fri Nov 29, 2019 3:50 am
alelanza wrote:
Thu Nov 28, 2019 2:00 am
PlatinumZealot wrote:
Some fighter Jets have sharp edges..

https://upload.wikimedia.org/wikipedia/ ... _Front.jpg
That's to reduce the radar signature prior to computer designed radar avoidance, not for good aero. It's also a bomber not a fighter, and it's been retired ever since for a better aero approach, f22 I think
Compare the thrust to top speed of this jet with other stealth fighter jets. :wink: before u say its draggy.
I think they also filtered the engine's output through a grill to minimise the Infrared Signature, which also limited the thrust available even further.

Tommy Cookers
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Joined: Fri Feb 17, 2012 3:55 pm

Re: Tesla truck, sharp edges and aero

Post by Tommy Cookers » Sat Nov 30, 2019 1:14 pm

well I thought the CFD by alelanza was interesting
rather like the 60s Le Mans-style 'ducktails' that reduced drag (and lift) but exasperatingly became called spoilers

and btw ...
djos wrote:
Thu Nov 28, 2019 10:55 pm
The reason the F117 has flat surfaces is due to the lack of computing power at The time it was being designed to calculate a radar reflecting shape with curved surfaces.
The B2 was the result of much more computing power being available and it has the radar cross section of a pigeon as a result. The only reason the B2 needs computers to fly it is due to the flying wing design being inherently unstable, it has nothing to do with the stealth properties.
the calculations for 'radar defeating' shapes were freely published by a USSR scientist
before that ? the SR-71 had shape and coating for this - but eg was picked up by UK radar flying to the Farnborough show
flat surfaces are beatable by '3d' radars eg the Czech one that Russians took from Kosovo to prevent the US getting it

early highly unstable planes flew by having suitable analogue control/stabilisation systems
eg the Rockwell X-31 HIMAT evaluated both analogue and digital - digital was at that time inferior
digital is self-maintaining and now fast enough
aerodynamic instability means less energy loss in manoeuvre control and ride control and (importantly) for trim
but afaik may demand greater structural stiffness (higher loadpath natural frequencies) ie CFC structures

bill shoe
236
Joined: Wed Nov 19, 2008 7:18 am
Location: Dallas, Texas, USA

Re: Tesla truck, sharp edges and aero

Post by bill shoe » Sat Nov 30, 2019 11:31 pm

Just_a_fan wrote:
Tue Nov 26, 2019 12:48 pm
bill shoe wrote:
Mon Nov 25, 2019 1:41 am


American full-size pickups and SUV's get their top dollar because (among other reasons) they are the only remaining bastion of body-on-frame architecture and the excellent Ride/NVH isolation that comes with it.
Aren't they classed as trucks and thus not required to meet the safety and emissions rules applying to cars? Hence they can be cheaper to make and thus can be sold at an attractive price. Of course the big pickups are very macho which appeals to many.

You can get excellent ride/NVH from a unibody too - the mechanicals are mounted via bushed subframes after all so there is no difference in the path from road to occupant in either type. As shown by the likes of Jaguar etc.
Pickups are classed as light trucks. They have to meet all the safety requirements of cars. In real-world accidents with other vehicles, pickups are safer than cars due to higher weight and higher height/CG. Rollover risk of higher CG is largely gone due to electronic controls (stability control, rollover control).

GHG Emissions in the U.S. are different for cars vs trucks, and trucks have it easier (generally speaking). This is why many car-type unibody vehicles are trying to technically classify themselves as trucks.

Any type of vehicle architecture can be executed well or badly. But if you take an experienced vehicle evaluator, force him to drink a 6-pack, beat him soundly about the head with a large club, blindfold him, stick him in a random car or light-truck, and tell him to drive, I guarantee they will determine in a few seconds if they are driving a body-on-frame or unibody. The difference is that fundamental.

The difference comes from the fact that the full-frame's natural freq (6-10 hz) is lower than the suspension secondary frequency (10-15 hz), therefore the full-frame is an extremely effective barrier against road-induced Ride/Noise getting into the body. Unibody subframes with bushings help but they do not have this fundamental quality that full-frame vehicles do.

After all that hand-waving, I would love to have a Jag!

alelanza
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Joined: Mon Jun 16, 2008 4:05 am
Location: San José, Costa Rica

Re: Tesla truck, sharp edges and aero

Post by alelanza » Sun Dec 01, 2019 3:51 am

Some interesting initial CFD on this, a ton better than I expected, almost hard to believe

https://www.goengineer.com/2019/11/27/c ... imulation/
Alejandro L.

foxmulder_ms
2
Joined: Thu Feb 10, 2011 7:36 pm

Re: Tesla truck, sharp edges and aero

Post by foxmulder_ms » Sat Dec 07, 2019 4:35 pm

I love it and ordered one. Stainless steel was too good to pass :) Love it!! =D> =D>

cplchanb
2
Joined: Tue Jan 31, 2017 6:13 pm

Re: Tesla truck, sharp edges and aero

Post by cplchanb » Mon Dec 09, 2019 9:26 pm

alelanza wrote:
Sun Dec 01, 2019 3:51 am
Some interesting initial CFD on this, a ton better than I expected, almost hard to believe

https://www.goengineer.com/2019/11/27/c ... imulation/
wait and see until the real production version is released. So many of this truck is not up to regulation, which includes the potentially sharp edges. Not to mention mirrors are still missing.

Giblet
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Joined: Mon Mar 19, 2007 12:47 am
Location: Downtown Canada

Re: Tesla truck, sharp edges and aero

Post by Giblet » Tue Dec 10, 2019 3:50 pm

Mirrors can be literally slapped on at the last minute, and they are not required if there are cameras in place in some countries.

The edges are sharper than typically rounded ones, but they are not actually sharp.
Before I do anything I ask myself “Would an idiot do that?” And if the answer is yes, I do not do that thing. - Dwight Schrute

Cold Fussion
136
Joined: Sun Dec 19, 2010 3:51 am

Re: Tesla truck, sharp edges and aero

Post by Cold Fussion » Sat Dec 14, 2019 4:46 pm

If you don't care about aerodynamics at all then it can be a last second job.