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Old 10-23-2008, 12:04 PM   #9 (permalink)
Ptero
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Join Date: Oct 2008
Location: California
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Smart Car ForTwo Pure - '08 Smart Fortwo Pure stripped
90 day: 51.35 mpg (US)

BMW 750iL V12 - '90 BMW V12
90 day: 26.4 mpg (US)

Wildfire 250C - '08 Shandong Pioneer 250C
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Quote:
They have lowered the whole vehicle by ~4 1/2 inches, and the front wheels are move further back -- these changes will stabilize it, and make it much harder to rollover.

I bought a Trimagnum reverse trike very similar to this one in 2000. According to Popular Mechanics, the skidpad rating exceeds that of a Corvette. There is a critical relationship between the wheelbase and front axle track dimensions and center of gravity on reverse trikes. If you get these dimensions right, the reverse trike is as formidable on a race track as a 4-wheel vehicle, with no unexpected tendency to slide the rear wheel out.

FYI, I have just obtained an aluminum block Northstar V8 and drive for this Trimagnum, which will be converted to run on both gasoline and natural gas/hydrogen gas mixtures and provide around one horsepower for every 6 pounds. I am also installing a MacPherson strut front end which requires conversion to a single seat and an aircraft-type canopy.

Talk about ecomodding, Robert Riley, who sells the plans, is now designing a diesel PHEV called the XR3 using the TriMagnum concept. His progress can be followed here:
http://www.autobloggreen.com/photos/...s-pics/980066/

Aptera has additional concerns about how the public will unknowingly alter the center of gravity and perhaps the stability of the vehicle. We have witnessed a steady progression from the optimized original to this compromised model, but a .cd of .15 is still spectacular.

The Canadian Vehicle Code addresses reverse trikes in a scientific way that is worthwhile reading:

Vehicle Stability

505. (1) Subject to subsection (2), the height of the centre of mass, shown in Figure 1, of a motor tricycle or a three-wheeled vehicle shall not exceed one and a half times the horizontal distance from the centre of mass to the nearest roll axis, shown in Figure 2.

(2) Subsection (1) does not apply to a motor tricycle designed in such a way that it leans during a turning manoeuvre in the same direction as the turn.

(3) The total weight of a motor tricycle or three-wheeled vehicle on all its front wheels, as measured at the tire-ground interfaces, shall be not less than 25 per cent and not greater than 70 per cent of the loaded weight of that vehicle.

(4) The loaded weight of a motor tricycle or three-wheeled vehicle and the location of its centre of mass shall be determined under the following conditions:

(a) the fuel tank is filled to any level from 90 to 95 per cent of the vehicle fuel tank capacity;

(b) a 50th percentile adult male anthropomorphic test device or an equivalent mass is located at every front outboard designated seating position but, if an equivalent mass is used, its centre of mass shall coincide, within 12 mm in the vertical dimension and 12 mm in the horizontal dimension, with a point 6 mm below the position of the H-point as determined by using the equipment and procedures specified in SAE Standard J826, Devices for Use in Defining and Measuring Vehicle Seating Accommodation (July 1995), except that the length of the lower leg and thigh segments of the H-point machine shall be adjusted to 414 mm and 401 mm, respectively, instead of the 50th percentile values specified in Table 1 of that standard; and

(c) adjustable seats are placed in the adjustment position that is midway between the forward-most and rearmost positions and, if separately adjustable in a vertical direction, shall be at the lowest position but, if an adjustment position does not exist midway between the forward-most and rearmost positions, the closest adjustment position to the rear of the midpoint shall be used.

(5) For a motor tricycle or three-wheeled vehicle with one wheel at the front and two wheels at the rear, the horizontal distance from the centre of mass to the nearest roll axis, shown in Figure 2, shall be determined using the equation

d = L sin (arctan (t / 2W))

where

d is the horizontal distance from the centre of mass to the nearest roll axis;

L is the longitudinal distance between the centre of mass and the centre of the front axle;

t is the width of the wheel track of the rear axle; and

W is the wheelbase.

(6) For a motor tricycle or three-wheeled vehicle with two wheels at the front and one wheel at the rear, the horizontal distance from the centre of mass to the nearest roll axis, shown in Figure 2, shall be determined using the equation

d = (W - L) sin ( arctan (t / 2W))

where

d is the horizontal distance from the centre of mass to the nearest roll axis;

W is the wheelbase;

L is the longitudinal distance between the centre of mass and the centre of the front axle; and

t is the width of the wheel track of the front axle.

(7) Motor tricycles manufactured before September 1, 2004 need not comply with this section.



Legend

h is the height of the centre of mass

L is the longitudinal distance between the centre of mass and the centre of the front axle

W is the wheelbase

Figure 1 — Side View



Legend

d is the horizontal distance from the centre of mass to the nearest roll axis

t is the width of the wheel track of the front or rear axle

W is the wheelbase

Figure 2 — Top View



Established by:
SOR/2003-272 24 July, 2003 pursuant to section 5 and subsection 11(1) of the Motor Vehicle Safety Act, comes into force 24 July, 2003.

Schedule IV is amended by adding section 505 after section 500.

SOR/2007-180 July 31, 2007 pursuant to section 5 and subsection 11(1) of the Motor Vehicle Safety Act comes into force August 22, 2007.

Paragraph 505(4)(b) of Schedule IV is replaced.
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Ptero

Last edited by Ptero; 10-23-2008 at 12:46 PM..
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