Renovation and aerodynamic improvement of a BPW closed trailer

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Christophe
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Christophe » 22/10/22, 16:05

I finished the comparative study, I give you the results of the drag force at 130 km/h, the overpower consumed, the Cx... but you don't deserve them because you were naughty... so I keep this topic locked.

Cubic Trailer:

Cx = 0,978
Drag force at 130 km/h = 1624 N
Power boost required at 130 km/h = 79,2 hp


Front area: 1,96 m²

Summary_cubic.png
Resumé_cubique.png (134.06 KiB) Viewed 1290 times


Semi-optimized trailer (without the Beluga):

Cx = 0,462
Drag force at 130 km/h = 767 N
Power boost required at 130 km/h = 37,5 hp


Front area: 1,96 m²

Summary_semi.png
Resumé_semi.png (118.48 KiB) Viewed 1290 times


Actual trailer as I built it:

Cx = 0,438
Drag force at 130 km/h = 720 N
Power boost required at 130 km/h = 35 hp


Front area: 2,2 m²

Actual_summary.png
Resumé_réelle.png (122.32 KiB) Viewed 1290 times


Fictitious real trailer (first idea but unrealizable for regulatory reasons) with rear fishtail:

Cx = 0,387
Drag force at 130 km/h = 632 N
Power boost required at 130 km/h = 30,9 hp


Front area: 2,2 m²

fishtail_summary.png
résumé_queue_de_poisson.png (216.74 KiB) Viewed 1290 times


These results do not take into account the towing vehicle (without comment), the underbody or the wheels, assuming that this is the same for all models.

The reality will therefore be a little worse, but the comparative orders of magnitude are there.

Conclusion: by manufacturing and using trailers designed by aerodynamic nags, we consume more than twice as much at 2 km/h and we often cannot even reach 130 km/h!! : roll: : roll: : roll:
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Christophe
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Christophe » 23/10/22, 12:09

Here is the almost final shape of the trailer:

final_form_trailer.jpg
trailer_forme_finale.jpg (458.78 KiB) Viewed 1210 times


I remember where I come from: : Mrgreen:

Image
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Obamot
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Obamot » 23/10/22, 17:10

First of all, it's a very nice result on very good technical “intuitions”. Simulations do it : Wink:

Although the original trailer was still “Shimano”?... : Lol:

I prefer the transformed where there's no more need to shit in the hands : Mrgreen:
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Christophe
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Christophe » 24/10/22, 10:16

I also simulated the profile of Eiffel (1/2 drop of water) with a max projected frontal surface of 2 m²... (not estimated the interior volume but it's close to the others)

I get at 130 km/h:
27,5 kg of drag
13,4 hp...
and a Cd of 0,162...


On the visualization, no eddies, no depression, no boundary layer separation... 8) 8) 8)

No trailer will do better than that...however, it's very hard to achieve as a shape, apart from a large mould, I don't see...
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Obamot
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Obamot » 24/10/22, 13:18

If yes, why? Make it fiberglass? Still needed a mold (and now it exists) 8)
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Macro
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Macro » 24/10/22, 15:37

I would have to check if my Czéro which has almost the profile of Eiffel but reversed with respect to the direction of travel ... consumes less in reverse than in forward ....
citroen-c-zero-2017-ausen-seite-dynamisch.jpg
citroen-c-zero-2017-ausen-seite-dynamisch.jpg (85.19 KiB) Viewed 1090 times



But good with my cervical hernia it will be complicated : Cheesy: : Cheesy: : Cheesy:
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Christophe » 24/10/22, 15:58

Macro the answer is most likely yes...remember to remove the wipers all the same : Mrgreen:

Reverse gear is limited in km/h on EVs, by the way? : Lol: : Lol: : Lol: : Lol:

ps: don't ask me why these (cons of) engineers from Citroën have reversed the direction of advancement! No doubt for their career advancements... : Mrgreen:
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Macro » 24/10/22, 17:13

Yes the speed is limited in reverse ... The engineers who designed it ... Are not those of lemon but those of mitsubishi. Japanese product designed to pay a minimum of taxes in Japanese cities minimum surface area for 4 passengers... Originally in Japan, it's a thermal...
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Christophe » 24/10/22, 17:15

Shame about the bridle!! : Lol: : Lol: : Lol: : Lol:

It doesn't matter, it's the same! : Mrgreen:

Japanese or bad what! : Lol:
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Re: Renovation and aerodynamic improvement of a BPW closed trailer




View Macro » 24/10/22, 17:18

They are capable of worse... 1t7 90cv v max 145kmh
16666246572081224229604672737519.jpg
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