A recent windtunnel surprise, Volkhart V2 Sagitta
 

A German engineer K.C. Volkhart build, V2 Sagitta, was a rare aero-body built on top of the Volkswagen KdF-Wagen Type 60, Beetle. Two were eventually built, based on the work by famous German aerodynamicist Reinhard von Koenig-Fachsenfeld. It was initially designed to be a reliable & fast postal delivery/courier car for the Luftwaffe in WW2 but was only realized post-war with the funding from industrialist Sagitta. The clean body design (very similar to the dreams; Porsche 114 and Porsche 64) allowed a 1.1 liter 24.5 hp boxer engine to top speeds over 140 km/h or 87 mph! The recently measured body had a low drag coefficient 0.21 and a respectable 2.1 frontal area. Two times more aerodynamic than its base car and very close to it's contemporary family stablemate, the soon-to-be-available VW XL 1!!! 1947 VW Beetle-Based V2 Sagitta is More Aerodynamic than New Golf, Mercedes CLA! - Carscoops

1947-Volkhart-V2-Sagitta-4%5B2%5D.jpg (image)

1947-Volkhart-V2-Sagitta-2%5B2%5D.jpg (image)

1947-Volkhart-V2-Sagitta-3%5B3%5D.jpg (image)

1947-Volkhart-V2-Sagitta-1%5B2%5D.jpg (image)

http://static.autojunk.nl/pictures/2...6/image_05.jpg

http://static.autojunk.nl/pictures/2...6/image_02.jpg

http://static.autojunk.nl/pictures/2...6/image_03.jpg

http://www.history-of-cars.com/image...sagitta-15.jpg

http://www.history-of-cars.com/image...sagitta-18.jpg

http://www.supercars.net/gallery/119...41/1035978.jpg

Porsche's similar aero studies and shapes - precursors to the Porsche 356;

Type 114. Ferdinand did start with mid-engine layout! http://www.thebestporsche.com/news.php?extend.29

Type 64. Should have stayed with the engine midship. http://www.smcars.net/forums/attachm...yp-64-2700.jpg

http://www.youtube.com/watch?v=Dr-S44ODM9s

...dang it, a new favorite (except for those fender mirrors)

1947 beats 1951, below comparing it to several Porsche 356 coupes.

3-cars-similar_zps69f8db5f.jpg Photo by kach22i | Photobucket
http://i184.photobucket.com/albums/x...ps69f8db5f.jpg

Not too late to make a Bug kit with these beautiful lines?...or even a tired 914? Come on hot rodders, crossover to serious ecomodding!

Throw in a D15Z1!

Or better yet, the tried and true STi swap.

It's also reminiscent of the Porsche 60K10, a road rally car based on the KdFWagen (the early version of the Bug)

http://img.fotocommunity.com/images/...-a25455590.jpg



http://autoconcept-reviews.com/cars_...ome-1939-1.jpg



It was designed for a Berlin-Rome rally which was cancelled by the outbreak of the war.

-soD

1939, and even closer to the 1947 sample first posted.

More information here:
PORSCHE TYPE 60K10
http://strangevehicles.greyfalcon.us/picturesu/d1.jpg

I... I... I think I'm in love...

That car doesn't have engine cooling or cabin ventilation. Tyres are super skinny. Those modifications have big effect on aerodymic drag.

Please quote the source of your information.

From what I can see, all 3-4 cars mentioned are air-cooled and have inlets at the rear.

Porsche 356's have cabin ventilation, although as with the later 911 it's not very good.

Concorso D'Eleganza Villa D'Este 2012, Class C
http://www.madle.org/v12sagitta2.jpg

The Volkhart V2 Sagitta (1947) has inlets at the front, could be for the cabin ventilation, front brake cooling, horn, or a front mounted oil cooler, I do not know for sure but if I were to guess it would be cabin ventilation (actually looks like a fan). Cracking a window open I suppose would be an option.

Link to front end detail:
Flickriver: Fine Cars's photos tagged with koenigfachsenfeld
http://l.yimg.com/g/images/spaceout.gif
http://l.yimg.com/g/images/spaceout.gif

http://i184.photobucket.com/albums/x...psf90866e2.jpg

She's a beauty...

Nice...

My guess is that the round little thingy in front (with the grille), is the horn/hooter.

Could be, 1946 era VW horn. External and inset. http://i.imgur.com/Gh4ixnU.jpg

Ventilation system has to have inlet and exhaust ports. I don't see any ports for cabin ventilation. We know how bad ventilation early Beetles had. Why this car would be different in any way? In one of those pictures driver's side window is open. That gives us a hint how well the ventilation system works.

24 hp engine doesn't need much cooling. Beetle had a fan sucking air through that grille under rear window. I would't compare that to a 90 kW CLA. Volkhart V2 is sealed like a bottle compared to a modern car.

Yes, the cracked window is a good indication, nice catch.

About the engine, you got me to thinking about those wind tunnel images. I wonder if the engine is running and drawing air down? If the engine is not running at a high rpm, then is this wind tunnel photo a fair representation of real world conditions?

I've looked around at early VW Beetles, no pre-windshield cowl inlets as with other cars - ever. The earliest VW's did not even have a dash slot for defrosting, therefore the Volkhart V2 ventilation is no different from the stock cars (said aero advantage or not).

I did find some curious rear window seal conditions, doubtful a one off prototype would have operable rear vent windows, but possible. Tell me what you think, could have been remedied in a restoration.

V2
http://static.autojunk.nl/pictures/2...6/image_02.jpg

Stock VW
Late '50s-early '60s Beetle, interior - a photo on Flickriver
http://l.yimg.com/g/images/spaceout.gif
http://i184.photobucket.com/albums/x...ps3d598d96.jpg

See attached image below for rear side window.
2-1035978_zps435760b3.jpg Photo by kach22i | Photobucket
http://i184.photobucket.com/albums/x...ps435760b3.jpg

http://i184.photobucket.com/albums/x...ps64dca095.jpg

Not to say 'Told ya so', but I've pointed to the Volhart-Saggita a few times: Permalink

If that vehicle had been on sale in the 50s it would have had pop-out quarter windows as a dealer installed option (flow-through cabin ventilation from 1971 on). It does have defroster vents; but the stock batwing steering wheel is anachronistic given the later windshield wipers. The Beetle body is inhabitable in hot weather because of the door vent windows. Flip those suckers around and they are air scoops. The Volkhart-Sagitta has compound curve door windows. :(

Compare it to this
http://i.imgur.com/aO1h3.jpghttp://i.imgur.com/H4HnS.jpg

...and you will see that while the V-S cabin is 4-passenger (where the Porsche Type 64 has two staggered seats), still it's optimized as a high-speed courier for the Luftwaffe. The top of the rear seat back is substantially higher than the window line, and you definitely not wearing your helmet in the back seat. :)
http://i.imgur.com/j0OLs.jpg

These both (all three) definitely need to be re-popped in fiberglass. There was an active industry in the 1980s cloning MG-TDs, Cobras & etc.

The Type I/II lends itself to engine swaps (Evinrude outboard converted to steam?) . Here's a complete electric drivetrain in the form factor of a 911 transaxle:
http://i.imgur.com/6KNJi.png

There was an active industry in the 1980s cloning MG-TDs, Cobras & etc.

inlet
 

I think that what is pictured is the horn.Not sure.

That seems to be the consensus, it's what I now think it is anyway.

I'm not sure where a stock pre-1967 VW Beetle gets it's fresh air intake from though. My guess is that the Volkhart V2 Sagitta would be similar.

Sagita inlet
 

From the photos,there is nothing which leaps out at us.If they do exist,it's possible that they are concealed behind the split bumper sections.These are located in the stagnation bubble,and even though there is no direct path into these areas,they would nonetheless have access to the ram pressure there,allowing harvesting for the cabin.
My Karmann Ghia takes it's air from this same location,although the bumper is below.Pressure is pressure,so air's got to flow if presented with a differential.
Another thought is that the inlet ducts on a K.G. form an integral structural member for the body.If hidden inlets ARE present on the Sagita,it's body would (could) enjoy the same.

In 1947 it would have been the door windows. Other options were the roll-back sunroof and the convertible. In 1951-52 VW tried 'crotch coolers', like a cowl vent except there were two in the front quarter panels—before they went to vent windows. I'm not sure what year was first for accessory pop-out quarter windows.

By 1967, you could have a 21-window bus with a fold-out Safari windshield and a full set of pop-outs. The only window that wouldn't open is the backlight. Those are available as an accessory today.

A Ghia like aerohead's dates from 1956. Flow-through from 1971.

...and it's a horn. Harley Davidson uses the same single post mount on the back, in case you want chrome. :cool:

Back in the day with an air-cooled rear engine I have to wonder it detached flow was beneficial and intentional...

Good point.

Opinions? Duck tail vs. Carrera Tail (aerodynamically speaking) - Rennlist Discussion Forums
http://forums.pelicanparts.com/uploa...1087934144.jpg

When Porsche first put the "ducktail" on the 911 it decreased lift and increased cooling by building up air pressure before the tail and allowing the fan to draw in more air.

http://forums.pelicanparts.com/porsc...to-engine.html
http://forums.pelicanparts.com/uploa...1311369953.jpg

From the above thread:

Not sure what you're saying here. One could say flow is laminar, attached turbulence or detached. You never see laminar flow in ground effect, detached flow will communicate the base pressure forward and spoil cooling intake.

The Volkhart Saggita's cooling intake is similar in form to the split window bus—flush slots. With the bay window bus the back of the slots is pulled out to make an angled scoop. With the Vanagon it's reversed, with the back pulled in to make a recessed scoop. :confused:

Here's the way the cooling is laid out:
http://ecomodder.com/forum/member-fr...-hlung-svg.png

Here's the stock bodies air flow:
http://ecomodder.com/forum/member-fr...o-scoop-vx.jpg

This appears to be a racer, the stock engine compartment has a floor that separates intake and cooling air from the hot components and exhaust.

If you want to eavesdrop on people dealing with this on a daily driver basis, try:
thesamba.com: Big CC in a bus = running Hot?
thesamba.com: Adding modern scoop for split bus engine bay cooling / pres.
On the 2nd page of that last one, someone talks about a F1 style diffuser to pull hot air out of the vehicle. :thumbup:

The cooling intake is right before the point of separation (hopefully). The diverted air probably 'pulls down' the flow that wants to detach.

All air-cooled VWs and Porsches that I know of had that separation. Maintaining it is very important in anything but a racer, which is usually going fast enough and has enough air coming in to avoid re-ingesting warm air.

-soD

If the bottom rear slope of old bugs where air vents are located are too steep to support attached flow then I wonder why. It occurs to me that suction effect from flow detachment could aid in cooling an air-cooled rear engine. Tufts tied to vent slots should confirm flow direction at speed...

This effect is easily achieved by propping open the engine compartment lid of either a Type I or II. The *intake plenum* is exposed directly to base pressure. Then people argue endlessly about the varying results. Examples are shown in the Samba threads I linked. I finished reading those this morning.

The aid you seek would come from exposing the exhaust of the cooling ducts and under-car airflow to base pressure. Which is why the diffuser appeals to me. The designed shape of it would be would be critical. I have no clue.

To bring it back on topic, the rounded tail of the V-S could be brought up to date with Coanda nozzles fed with engine cooling air exhaust.
http://ecomodder.com/forum/member-fr...25-7-36-55.pnghttp://ecomodder.com/forum/member-fr...70-imagesa.jpg

The original 25hp engine didn't move much air, but it's at 5 psi.

beneficial and
 

All the air-cooled engines of course have forced-air cooling from the generator shaft.So,in a sense,it doesn't matter where the air comes in from,as engine power is robbed to provide the pressure differential across the oil cooler and cooling fins.
That said,the flow separation,while lowering the base pressure behind,does maintain a downwash,with momentum carrying the airstream down on a collision course with the body.By locating the inlet at the site of the collision,you can harvest this downwash,easing the horsepower requirement of the cooling fan.
In a modern application,the ghost of Ferdinand Porsche might utilize NACA submerged inlets to bring air into the engine bay.
The Lange car form,which Porsche used,according to Hucho,had Cd 0.14-16 in scale-models,so you can imagine how attractive this might seem at a time when 'conventional' cars were Cd 0.6-7.

It is always interesting to see the front skirts. Sometimes the wheels seem too close to be able to turn well.

steep
 

Hucho says that the longitudinal vortices of the Bug's pseudo-Jaray roofline will help induce a high deflection attached flow downwash at the center of the back.This would aid cooling,although the high drag vortices would raise the road load,requiring more power (heat flux) which would have to be dealt with.
In 1936 or so,the Beetle's Cd 0.495 would have been considered quite low compared to contemporary cars.

I found an image showing the flow off the sides of the car : http://i877.photobucket.com/albums/a...artsagitta.jpg

ducktail
 

Yes,the ducktail receives the downwash off roof increasing the pressure differential across the heat exchanger(s).
http://i1271.photobucket.com/albums/...d2/06-2815.jpg

Back in July, I spotted this in Italy at the Villa D Este Concourse D'elegence, in the underground garage. I was told it was the only one. Mind you the event was full of one off specials.

Very pretty in the flesh & tiny my modern standards
http://i76.photobucket.com/albums/j7...ps1fd94779.jpg

I've just realised the pics of the Volkhart on display are from the same event & I missed it!

BMW 328 MM Touring Berlinetta.
http://www.smcars.net/attachments/bm...tta-gif.33826/
Personal site - BMW 328 MM Touring Berlinetta