Kammback / Tailgate wing for Volvo 245 (wagon)
 

Here's where I am with my attempt at reducing drag due to low-pressure zone at that very steep tailgate! Made with heat-formed PVC sheet (0.5 mm). Anyone interersted in knowing more about how I did it, or - more importantly telling me whether I've wasted my time or not :-)

https://ecomodder.com/forum/attachme...9&d=1675780709

Tuft it with long tufts. If they indicate the flow over the bed now misses the top of the tailgate, then you are successful. Couple of pool noodles jammed in the bed to cab junction wouldn't hurt either.

One of these things is not like the other.

Apparently I mistook it for a pickup, probably shouldn't play with power tools again today.

Took me 4 hours to change the SSAN auto post payments in quicken

No problem :-) I learnt something useful for the eventuality that I ever have a pick-up with a separate cab and bed :-) In fact, by extension of the logic, it should also work between a normal car and a trailer, though one would have to have a MASSIVE pool noodle :-) :-) :-) I might be trailing sometime this year: any ideas for how to bridge the gap between my steep-back Volvo 245 and a box-shaped trailer?

That's a tough one. It has to accomodate movement in three dimensions (pitch roll and yaw). A flexible solution would have to resist flutter.

Shorten the gap as much as possible.

https://ecomodder.com/forum/member-f...untitled-4.jpg

Modern tractor-trailer combos use hinged plates. Look to chain maille or segmented armor (armadillos). A chamfered nose on the trailer (like the Cybertruck) is better than a V-shape in crosswinds.

Six foot lengths of pipe insulation come in a variety of sizes.

'wasted or not'
 

LUCID's lead designer, Derek Jenkins is claiming that their upcoming 'Gravity SUV' will be the 'most aerodynamic SUV ever,' and their 'flow extender' will be 'massive.'
So I think your instincts are A-Okay.
And 'size matters.'

tow vehicle to RV trailer gap
 

If this takes, it's an inflatable gap-filler from the UK, powered by a 12-VDC car vacuum.
https://ecomodder.com/forum/member-a...l-trailers.jpg

Volvo 245 @ 40-to-70 mph'
 

I found a CAR and DRIVER road test for the Volvo 760 Turbo-Intercooled Wagon.
It's 'larger' and heavier than the 245, but you may be able to adjust the data using delta-frontal area, and delta-curb weight.
* the larger 760 has 2.16-meters'squared area, vs 1.95 meters-squared for your car.
* the 760 is 1467.82-kg curb weight. I don't know the weight of your car.
* both 760 and 245 are Cd 0.41.
* the 760 has the BOSCH LH-Jetronic fuel injection.
* the 760 has AiRsearch TB03 turbo, with 14-psi boost.
* the 760 has Pirelli Cinturato P7, 205/55 VR-16 tires, Cfrr- 0.0154413.
* the 760 has 4-speed trans with electrically-locked overdrive, @ 41 km/h per 1,000-rpm.
* 137.954-kW power.
* 205-km/h top speed, @ 4984 rpm.
* EPA HWY 9.0467- L/ 100 km
-----------------------------------------------------------------------------------
Guestimating from known aero-mods, depending on what you'd be allowed to do, without adding any length to the 245, there's a high probability that you could reduce drag down to Cd 0.266, delta Cd 0.144, delta drag 35.12%, with an mpg increase of 17.5% according to 1978 SAE automotive metrics.
If you added length, you could do better.
Mods would include:
A-pillars
wheel covers
rear skirts
belly pan
rear diffuser
rear roof wing
aero mirrors
rear tire deflectors
wrap-around airdam extensions
rocker panel extensions
partial grille block
-----------------------------------------------------------------------------------
* synthetic engine oil would make a minor improvement
* synthetic differential lube would make a more significant improvement
* LRR tires would make a significant improvement ( Cfrr 0.0055 Bridgestone Ecopia for example ).

Love the idea of the inflatable trailer gap-filler: clever :-)

Many thanks indeed for the advisable mods for my 245. I think I'm right to prioritize the extension of my front lip with a skirt that extends below the current lip; under-belly pans and the pan for the rear under-body where it meets the "parachute" bumper; moderate rocker extensions: I have an early 245, so the bumper is a bummer... I'm in Germany, so I have to be careful that the mods I do are either concealed, or look like things that are in the official legal list of add-ons - e.g. side skirts etc. EVERYTHING here has to have a certificate of conformity, otherwise one ends up paying enormous fines or having to take them off before the ministry of transport examination every two years...

Interesting, thanks for the FYI.

Lucid Gravity previewed as the 'most aerodynamic SUV ever'
https://www.autoblog.com/2022/11/15/...ravity-teaser/

ademonrower, nice work.

More photos would be welcomed, the leading edge in particular is of interest, and how it's all secured - the details. :)

Partial kammback Volvo 245 attachment method
 

I must apologize for not being able to find the message that requested more details on how my improvized flow-extender for the tailgate of my Volvo 245 is attached. Here are two pictures that should help. Cheers

Double sided tape, maybe a great idea, maybe a really bad idea - time will tell.

Thank you for the additional information.

Yes, I agree with you: I'm not "convinced" of the double-sided tape either, but if it is the thick kind with foam or flexible polymer between the two sticky layers, it could make a firm enough bond. I'd like other ideas on the affixment question, because it's a very important one, so please - anyone - feel free to advise me. Thanks!

Super [ethyl 2-cyanoacrylate] glue? Deadheres with rubbing alchohol.

'affixing the wing'
 

* the flow extender will not be exposed to significant aerodynamic loads, and some tape systems adhere so strongly that, you might destroy the device whenever you attempt to remove it.
* a lanyard, like Chrysler Corp. used on their 1969 Dodge Charger Daytona Coupe rear wing, to ensure it wouldn't strike another race car should it be knocked loose in a race, might be enough 'insurance' for your device.
* other than some structure which is captured within, and held steady in the gap of the rear hatch, from which the 'wing' could be attached to, I don't know of many options for sturdy attachment that wouldn't damage the Volvo's paint.
* I don't think you want to drill holes in body parts, and then run fasteners 'out' through the hole, into a female threaded insert, bonded to the 'underside' of the 'wing,' with a weather-proof gasket, like carmakers do.

Very good ideas and advice: indeed, NO to drilling holes: bad thing for a classic car, but your message made me think, perhaps I can make a clip-on fastner to the vertical rim of the tailgate: that would, at least, give the extender a holdfast at the side as well as on the roof-level rim of the tailgate... Will experiment and post pics...

Here's some inspiration from another guy with a boxy station wagon:
https://ecomodder.com/forum/showthre...mph-13476.html

I'm following to see the results since I want to add a similar spoiler to my SUV :)