Project 100 (custom enclosed Honda C90 targets 100 mph vmax and 100 km/L FE)

[Frank Lee]

They had a lift problem.

[Patrick]

Originally Posted by Frank Lee

They had a lift problem.

Now that's a good one!

[visionary]

Frank – after reading your earlier post re drag calcs, I decided to look at it again.

First the Crr – I read the notes and without any other information I reasoned the low figure on the basis of m/cycles having only two tyres (half the energy consumed in deformation of contact patch) versus 4 on car – so half an average figure.
I didn’t expect to be far from the ball park, but I bow to your superior knowledge.
I have now re-run figures with .018 (middle of your estimate)

Frontal area – just completed a count (by hand) of size. I have a photoshop drawing, which I will post once I tidy it up, but the count came in at 0.673sqm – so actually less than my estimate of 0.7sqm. Again I have re-run the calc with this new input.

Cd – well this is a guess, but at least an educated one! In my initial research I found a figure of 0.17 for the ecomobile and I gave myself some “wriggle room” by using 0.19. The ecomobile is the nearest design to mine, with two exceptions (one positive ,one negative)
It runs enclosed wheels and I intend open, but it has exposed outrigger wheels at the widest part of the body which I think will cause turbulence, whereas my design is very smooth at should keep flow attached for longer.

Anyway, the net result is still only 11.5hp to hit 100mph, which is still attainable, so I’m not put off yet.

By the way, I think you are spot-on about your aerodynamic observations – I expect turbulent flow around the front wheel to quickly re-attach at the body sides, thus minimising the drag penalty. My big problem is the rear! I’m still open to suggestions about how to finish this.

[Frank Lee]

Number of tires on the ground are not part of the formula in the EM calculator. Hadn't thought about that!

[visionary]

First in this update is the frontal area calculation image. The sketch is to scale over a CAD drawing and has been overlayed with a grid and scale dimensions. Each square of the grid has been counted into sections with partial squares estimated at the edges. This version of the count is “cleaner” and more accurate than my earlier posting, but confirms the frontal area at less than 0.67sqm used in the aero calcs.




I’m also posting this comparison drawing of the project vehicle and a normal motorcycle (actually BMW), which shows the aero gains from my low seat height and enclosed body design. I will post a couple more of these comparison images over the next few days, as I believe they are quite instructive

[Frank Lee]

This is going to be operated by humans? Not radio control?

My helmet is wider than the greenhouse; were I able to scrunch down lower to where it is wider I still wouldn't be able to turn it side to side. And I'd split the bodywork open if I inhaled.

[visionary]

Frank - what can I say?
It is my hope that this type of vehicle (fully internal seating, crash protection and restraints) would be exempt from helmet laws. If so, the canopy dimensions are more than adequate, but I agree - if you have to wear a helmet (which i will initially) then its gonna be a bit "cosy"
As for height - I'm 5"10 and its spacious - a couple of people 6foot plus have tried it with no problem.
As for width - OK, hands up - its not made for the overweight, but at 560mm internal panels it should suit most people. I modelled the seating position on a Toyota MR2 Mkll that I used to own at that was fine!
I was just about to post seat pictures - to follow!

[visionary]

Here is the donor seat - its from a early 90's BMW 5 series. It was about the only leather seat in the scrap yard, virtually everything else is cloth, but I need a wipe-clean and waterproof material until the canopy is done



Here is is stripped down (using back only) and mounted. The frame shows how it fits within the 560mm space between the side rails (600mm external) and still gives 50mm (per side) for bodywork. This gives a maximum width of 700mm, which is less than a Honda PanEuropean and will go through a normal house door

[Frank Lee]

My helmet is 27.5 cm wide at the visor pivots and 36 cm long. The front view shows 35 cm at max width? What units are those squares anyway?

[visionary]

Frank - each square is 20mm x 20mm. The max width is 35squares or 700mm and the width across the "greenhouse" at mid height exceeds 400mm thus allowing your helmet side on, with ease.
The seat in frame photo is exactly to scale with the "sketch" which is itself taken from my AutoCad drawing.
I think we could agree to call it "snug" but this is meant to feel like a racing car not an RV!