Random Aerodynamic Oddity of the Day Thread

[Bicycle Bob]

Not like that. A front engine improves stability and crashworthiness, and the variable load area should be close to the center of pressure.

[freebeard]

The rear-engine Dymaxion was based on flathead Ford technology. The Dymaxion 4 would have had three-wheel drive and hub motors.

They weren't 'cars' but test vehicles for his proposed Omnidirectional Transport triphibian. In airborne mode the usual aircraft load balancing issues would have applied.

[kach22i]

Originally Posted by Bicycle Bob

Not like that. A front engine improves stability and crashworthiness, and the variable load area should be close to the center of pressure.

A Porsche.911 has near perfect 50/50 weight distribution under hard braking.

Think about that if you will.

https://www.caranddriver.com/feature...1-gt3-feature/

[freebeard]

Mute this and put it on 2x.

Everything from shiny 50-yr-old Cadillacs to bobber trucks.

https://www.youtube.com/watch?v=0p-iZmSE9ww

[kach22i]

Originally Posted by freebeard

Mute this and put it on 2x.

Everything from shiny 50-yr-old Cadillacs to bobber trucks.

I did as suggested and watched the first five minutes but didn't see anything aerodynamic so I scrolled along here and there.

The beauty contest was interesting.

Definitely some automotive oddities there.

The record-breaking Guzzino
The record-breaking Guzzino | Italian Ways

Easy to drive and weighing in at only 45 kilograms, the Guzzino – with the addition of a fairing to reduce drag – was also a great vehicle for sport competitions and record-breaking performances. In 1948, on the road between Charrat and Saxon in Switzerland, it set the world speed record over the kilometer and the mile; later in the same year, it set another 19 records at Monza’s racetrack.

The Guzzino kept going faster and faster as the years went by. It was restyled more than once, finally coming close to resembling a rocket: pilots had to ride in a position known as “the frog”, with their knees around the fairing that protected the chain, and their feet on the foot boards on the back of the frame.

[kach22i]

The body curves as I've been drawing for a while. Unusual to see this in hovercraft.

New Hovercraft Kaiman 2016

https://www.youtube.com/watch?v=TBFI-XFLET0

Two engines hovercraft. Subaru 240 hp for thrust, Kohler 38 hp for air cushion.

[Bicycle Bob]

That profile looks like it could be aircraft surplus, but I don't see aircraft speeds to demand it.

[kach22i]

Originally Posted by Bicycle Bob

That profile looks like it could be aircraft surplus, but I don't see aircraft speeds to demand it.

Not aircraft surplus, trust me.

Anything over 30 mph demands aerodynamics in my opinion.

This isn't like a boat displacing water that's 100 times denser than air.

A hovercraft is lubricated from the surface by 1/2" or more of air escaping from the partially captured cushion of air beneath the craft.

I'm pretty sure that craft can do about 50 mph, faster with a tail wind.

EDIT:

Finnish Hovercraft Company Oy
Kaiman-10
https://www.finhov.fi/ilmatyynyalus/kaiman-10/

Hinta

Speed
Max. Speed: water 80 km/h

ice and packed snow 120 km/h

Cruising Speed: water 60 km/h

ice and packed snow 70 km/h.

(Max. speed is dependant on weather and operation platform condition)

EDIT-2

I did a conversion online

80 km/h = 49.7097 mph

120 km/h = 74.5645 mph

Cruising speed on water 60 km/h = 37.2823 mph

Aerodynamics would certainly become a factor.

If I posted other hovercraft you would recognize just how special this craft is, many of the other ones are crude looking by comparison.

EDIT-3

https://christyhovercraft.com/compan...manufacturing/


These are two different makes, and the Christy above (Russian) was formerly one of the cleanest designs, it's been displaced by the Finnish hovercraft below.

https://www.finhov.fi/ilmatyynyalus/kaiman-10/


The British Griffon isn't a slouch, but most of their models are boxy, but getting better all the time.

Griffon Hoverwork 995ED
https://www.griffonhoverwork.com/995ed


Looks like future models will be following suit.

http://www.nauticexpo.com/prod/griff...50-429411.html

[kach22i]

These bow thrusters are more aerodynamic than the round rotating elbow nozzles older models use.

Griffon Hoverwork - Land Sea and Air Magazine

The 12000TD also features new technology that Griffon has pioneered. Mixed aerodynamic flow fans are used to minimise power taken from thrust for lift and compact permanent magnet generators, motors and an in-house developed power electronics control system is used for the bow thrusters. Development of the latter was a result of work on a new small hovercraft using diesel electric drive, the 995ED, where the electric solution allowed distribution of machinery around the centre of gravity to obviate the need for ballast.

Hovertravel Island Flyer

https://www.youtube.com/watch?v=PfSKaGQFoYc

Compare to other (old school) bow thrusters below.

AP1-88 hovercraft with Hovertravel:: jameshovercraft.co.uk

[kach22i]

Hydrodynamic...................

Propeller Tunnel
https://www.servogear.no/controllabl...opeller-tunnel

Reduced Hull Resistance

Based on experience from sea trials and model tests, a propeller tunnel normally reduces the hull's resistance in water. The reduction in resistance is caused by less transom area, which again reduces the loss in stern wave.