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Lotus Europa Forums => Garage => Topic started by: jbcollier on Saturday,January 09, 2021, 06:57:38 PM

Title: Prototype in the wind tunnel
Post by: jbcollier on Saturday,January 09, 2021, 06:57:38 PM
(https://photos.smugmug.com/Lotus-Europa/i-FwxGKzM/0/f22342bb/O/large.lotus-europe-detail_aero-big.jpg.fe3e7da4ccebde20ff054d59a9662c3f.jpg)
Title: Re: Prototype in the wind tunnel
Post by: Bainford on Saturday,January 09, 2021, 08:54:57 PM
Interesting photo. Note how the tufts on the engine cover are doing something different than all the rest.
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Sunday,January 10, 2021, 08:10:26 AM
not really indicative how the air flows through the vents into the engine compartment and out through the rear grille though
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Sunday,January 10, 2021, 08:56:13 AM
Air flows in through the rear grill.  Not supposed to, but it does.
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Sunday,January 10, 2021, 12:35:06 PM
Air flows in through the rear grill.  Not supposed to, but it does.

And out ?
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Sunday,January 10, 2021, 12:53:23 PM
Sadly, no.  Engine compartment air recycling is a big issue.  What is needed are "positive" air scoops that force air in when the car is moving.  That would insure flow out.  The $64,000 question is how to do that in an aesthetically pleasing way.
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Sunday,January 10, 2021, 01:44:59 PM
Lou's photos on page 1 of the 47 pics has a good period photo of a scoop, seeing as the NACA duct doesn't supply enough air
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Sunday,January 10, 2021, 01:50:53 PM
sorry, your photo on page 2 of Lou's thread
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Sunday,January 10, 2021, 02:16:18 PM
Air flows in through the rear grill.  Not supposed to, but it does.

That would pull exhaust fumes in to the engine bay (and to the cockpit?), so every engine needs an airbox & be fed externally in reality
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Sunday,January 10, 2021, 02:35:21 PM
Yes, it does.  Not "all" the exhaust gets pulled in, but some for sure.  Air comes in through the front of the wheel wells where the box-section, radius arms run.  It goes up and out the cover vents and tumbles back.  Some gets goes down and back in leading to high engine compartment temperatures, as much as twenty over ambient.  In stock form, the best source of cool air is low in the front of the engine compartment.
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Sunday,January 10, 2021, 03:16:16 PM
These scoops work:

(https://photos.smugmug.com/Lotus-Europa/i-JwcLWjB/0/daabfb0b/O/large.cas01-autoscout24-ch.jpg.0cd93f269efdc90845b32d5f576a4aa1.jpg)

(https://photos.smugmug.com/Lotus-Europa/i-XHFTzrP/0/d825e853/O/large.cas01a-autoscout24-ch.jpg.0a027d748dba4a781c13abc7884c007d.jpg)

Aesthetically?  Not so much.  I'm thinking of running something similar but only on the driver's side (won't block rear view) and not venting into the cover but through side above the tank and ducted low to enhance through-flow.  Just thinking though, nothing mocked up.
Title: Re: Prototype in the wind tunnel
Post by: Sandyman on Sunday,January 10, 2021, 03:27:54 PM
John, I am thinking of the same thing. Sketching out some ideas. Single detachable scoop behind driver.
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Sunday,January 10, 2021, 04:08:29 PM
Love to see what you come up with.
Title: Re: Prototype in the wind tunnel
Post by: Richard48Y on Sunday,January 10, 2021, 06:12:59 PM
Rear screen can be blocked if this is really a problem.
Modern 12v fans can move a fair amount of air, maybe rear mount fans would expel air far enough to stop the tumbling recirculation?
Have to wonder how effective a flat extension above the rear vent might be. Not attractive, but how effective?
My headers are heat-wrapped but it's ugly, and I think there are now coatings that may be more effective as well as preventing rust.
Title: Re: Prototype in the wind tunnel
Post by: SteelCityLotus on Sunday,January 10, 2021, 07:55:04 PM
Yes, it does.  Not "all" the exhaust gets pulled in, but some for sure.  Air comes in through the front of the wheel wells where the box-section, radius arms run.  It goes up and out the cover vents and tumbles back.  Some gets goes down and back in leading to high engine compartment temperatures, as much as twenty over ambient.  In stock form, the best source of cool air is low in the front of the engine compartment.

I would be interested to see if blocking the engine cover vents forced the engine bay air to be sucked out of the number-plate vent. The car did not originally have a vent in the number plate area, at least mine doesn't, so that means the engine cover vents were necessary to extract heat. By adding a vent at the rear and blocking the engine cover, the pressure in the engine bay would not bleed out of the engine cover and, instead, bleed into the low pressure wake at the rear. NACA ducts or underbody modifications in addition to blocking these vents may also help keep air moving through the engine bay.

Is there a good 3D CAD model of the Europa available? I have CFD software on my company laptop and I've been itching to use it. I'm a novice with regards to the Europa, but I have a pretty solid education on motorsports aerodynamics.
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Sunday,January 10, 2021, 08:27:26 PM
If you know aero you're one up on me.  They alway had engine e cover ducts.  They closed off the rear panel for the TC.  Still gets hot in there.
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Sunday,January 10, 2021, 09:08:13 PM
Like I said, not aesthetically easy ;-)

(https://photos.smugmug.com/Lotus-Europa/i-CpXCKLw/0/10e65602/O/196553510_large.lotusavant.jpg.75396f8744e9cea2509d1392b88a3fb7.jpg)

(https://photos.smugmug.com/Lotus-Europa/i-j4wBWSc/0/74c723f6/O/730672895_large.ARlotus.jpg.91881e509a5443cee63f161b91b8f987.jpg)
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Monday,January 11, 2021, 06:13:43 AM
Extreme engine air flow control:

(https://photos.smugmug.com/Lotus-Europa/i-33dsxhh/0/67527a42/O/1103725406_large.20170825_153556%282%29.jpg.cd649e11f0088ce56bda4efa0572612e.jpg)

(https://photos.smugmug.com/Lotus-Europa/i-FDQbP9N/0/f53d467a/O/large.20180904_091851.jpg.c69ffc87a44a84003a582dfd76b0cda9.jpg)

(https://photos.smugmug.com/Lotus-Europa/i-CFhGgMN/0/19a64e5c/X2/large.big-5300436f6c.jpg.414d91d7f5c46ebda55824461f9f1dc9-X2.jpg)

(https://photos.smugmug.com/Lotus-Europa/i-BHGMPc3/0/59cd39c6/X2/large.IMG_20190305_142842.jpg.7fc55a3d48b6c8c753fc1ad6fa5f9384-X2.jpg)
Title: Re: Prototype in the wind tunnel
Post by: BDA on Monday,January 11, 2021, 06:58:25 AM
They sure were concerned about cooling!
Title: Re: Prototype in the wind tunnel
Post by: SteelCityLotus on Monday,January 11, 2021, 08:18:55 AM
If you know aero your one up on me.  They alway had engine e cover ducts.  They closed off the rear panel for the TC.  Still gets hot in there.

Thanks for clearing that up for me. I was wondering if the number-plate vent was something everyone added or if it came standard at some point. I'll be sure to look for that at the next car meet.

I'm still in resurrection mode at the moment, but small aero improvements are definitely on my list.
It will be interesting to see what is legal for the vintage racing and what rules can be interpreted...creatively.
I'll see if I can find some sort of 3D model to use in CFD to answer these questions.
Title: Re: Prototype in the wind tunnel
Post by: dakazman on Monday,January 11, 2021, 09:30:51 AM
  Well here is what my spitball looks like . One low profile , two vented sections from side to side .
Excuse the fast draft. Also has a third brake light and Minimal sight loss.
Dakazman
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Monday,January 11, 2021, 10:10:45 AM
These scoops work:

(https://photos.smugmug.com/Lotus-Europa/i-JwcLWjB/0/daabfb0b/O/large.cas01-autoscout24-ch.jpg.0cd93f269efdc90845b32d5f576a4aa1.jpg)

(https://photos.smugmug.com/Lotus-Europa/i-XHFTzrP/0/d825e853/O/large.cas01a-autoscout24-ch.jpg.0a027d748dba4a781c13abc7884c007d.jpg)

Aesthetically?  Not so much.  I'm thinking of running something similar but only on the driver's side (won't block rear view) and not venting into the cover but through side above the tank and ducted low to enhance through-flow.  Just thinking though, nothing mocked up.

One the Swiss S2s with the 807 crossflow motor
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Monday,January 11, 2021, 10:21:14 AM
Not sure that an original Swiss 807 has ever been found.  It's hard to tell as so many European Europas have been converted to 807/843 engines.
Title: Re: Prototype in the wind tunnel
Post by: RonPNW on Monday,January 11, 2021, 12:18:17 PM
I'm in the same boat as SteelCityLotus, doing body structural repair and wondering about what aero mods would be both worth it and visually pleasing.

I do not want to make any major visual changes so think that it is best to take advantage of and improve what is already happening to the car. I have relocated my air cleaner to take advantage of cool air that I have ducted from in front of the rear wheels by using a small flap / air dam in front of the rear wheels. If you look at many modern cars and do some searches you will find data showing that directing air away from the leading edge of the rear wheel reduces air drag. A vent in front of that flap could direct cool air to the engine compartment and up out of the rear bonnet vent. This is already the direction of air flow. I vaguely recall reading about a Lotus owner who did just that and reduced underwood temperatures by over 10 degrees with an associated increase in horsepower.

If anyone has access to CFD software I would be happy to try and help. Sadly I can only offer labor hours, I don't have any CFD experience.

Ron
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Monday,January 11, 2021, 12:25:51 PM
an 807 is what the car should have been, Colin Chapman should have negociated more & harder with Renault
Title: Re: Prototype in the wind tunnel
Post by: jbcollier on Monday,January 11, 2021, 01:22:58 PM
Renault already had contracts with the Alpine/Gordini crowd which prevented them from selling the special engines to another manufacturer.  Alpine and Gordini were NOT happy with the Lotus contract and made sure potential future access to the hemi engines was blocked, much to Chapman's disappointment.  Lotus then worked at adapting the TC which was not a particularly happy engine when federalized.  Renault gobbled up both Alpine and Gordini but it was too late by then.  Too bad as federalized hemis continued into the mid-80s.

Since the 1470 engine supplied to Lotus was so different to anything offered in a Renault vehicle, it lends credibility to the theory that they actually sold them surplus marine engines (identical pistons, etc).  The 1565 engines were all federalized engines which Lotus had to have to continue selling in the US market.
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Monday,January 11, 2021, 02:12:09 PM
yup, know all that (not the marine engines bit) still think he should have done more, helped Alpine / Gordini with suspension projects?, the hemi is such a jewel of an engine it had to be had
Title: Re: Prototype in the wind tunnel
Post by: GavinT on Tuesday,January 12, 2021, 07:36:51 AM
(not the marine engines bit)

Search for "Mercruiser 80"
This look familiar?

Title: Re: Prototype in the wind tunnel
Post by: dakazman on Tuesday,January 12, 2021, 04:02:17 PM
 I love the fuel line over coil. :blowup:
Dakazman
Title: Re: Prototype in the wind tunnel
Post by: Dilkris on Wednesday,January 13, 2021, 12:36:16 AM
Wow!!! That's got to be the quickest way of taking a stern drive + engine assembly out of a boat - just cut out the rear transom  :FUNNY:
I have been following this thread with some interest and whilst there are issues raised here that are beyond my grasp - is there not something to be learnt here from the installation of inboard boat engines (which I assume sit in static air) which would be applicable to the Europa ?       
Title: Re: Prototype in the wind tunnel
Post by: MRN I J on Wednesday,January 13, 2021, 03:00:13 AM
I think the Mercruiser inlet manifold would be ideal for a turbo instalation, Andy Short of BSS parts did one 25 years or so ago, based on a R18 or Fuego turbo
Title: Re: Prototype in the wind tunnel
Post by: GavinT on Wednesday,January 13, 2021, 08:18:00 PM
Wow!!! That's got to be the quickest way of taking a stern drive + engine assembly out of a boat - just cut out the rear transom  :FUNNY: 
Crikey, you're right . . I hadn't noticed that.
But the transom looks to have delaminated and falling apart anyway, so I'm guessing the boat wasn't worth much as a going concern.
Title: Re: Prototype in the wind tunnel
Post by: kram350kram on Thursday,January 14, 2021, 06:50:10 PM
Noticed that the "strings" in the center of the engine cover are pointing forward. Good place for an air intake to the engine? Maybe to much hot air there rising out of the outer openings?
Title: Re: Prototype in the wind tunnel
Post by: GavinT on Thursday,January 14, 2021, 08:17:50 PM
Here's a Lotus Elise in a wind tunnel. I always find these fascinating.

https://youtu.be/_BnHXfvZVFo

Given recent conversations about airflow and vents in the Europa engine cover, it looks like the Elise displays similar erratic air movement in the corresponding area.

Observe the video at the 2:54 point.
They're injecting smoke directly into the area in question.