Scooter efficiency and aerodynamics...

[Cycle]

Originally Posted by aerohead

*Only in a wind tunnel can the CP/CG relationship be verified
*As the symmetrical section encounters yaw,the forward stagnation point will also move (affecting your ability to harvest ram air)

Could one instrument the bike with yaw and wind speed or pressure sensors to have the ability to data-log as one was riding? Sort of a real-time wind tunnel. It'd have to be cheaper than paying for wind tunnel time, and you'd get real-world data to work with.

Originally Posted by aerohead

*Only a rigid surface can overcome aeroelastic phenomena which occur as the angle of attack varies,and velocities/pressures with it

The surface would be rigid when pressed inward by the air, but flex or articulate outward so I can put my feet down. Unsure how to implement that, but there's gotta be a way. Just have to kick my brain into gear a bit and it'll come to me. That's the hard part. Heh.

Originally Posted by aerohead

*In crosswind,the windward stagnation point would be a moving target,and the leeward wake also,making it very challenging to vector your air discharge to control your roll moment.

It's already a moving target, isn't it, what with all the oddly shaped surfaces in the airstream? I'm merely proposing to try to clean that up and redirect some of that air to where it'll be more beneficial. It'll change the overall behavior of the bike to any given side wind loading, but once that behavior is known, it can be adjusted and if needed compensated for by the rider, just as is done on the bike now.

Originally Posted by aerohead

*Any air you rob introduces a transverse contamination to the boundary layer which will affect an otherwise favorable pressure gradient (if you're gonna try a laminar profile).Once you reach the 1st minimum pressure,your at your point of BL transition to TBL and maximum lift

Wait... I was under the impression that the *lower* the pressure gradient fore to aft on the bike, the better. So by grabbing that air up front (and low) on the bike and cleanly ducting it rearward (and high), it would act to lessen the effective frontal area and lessen the effect of the airstream upon the bike's dirty bits, while acting as a "longer lever" than the side wind hitting the other side of the bike, thus helping to counteract that side wind loading. Wouldn't it?

Originally Posted by aerohead

*If you'll spin your front wheel and observe its spin-down time profile,it will suggest it's ability as a prime mover/air handler.I believe that you'll be shocked at its inability to develop any meaningful static pressure.

My rims look like three-bladed fans. For such small wheels, they push a lot of air, and it's gotta be turbulent at highway speed. A very bad design. That's part of the reason I'll be getting solid disc rims. The other part is that a solid disc rim makes it easier to mount the sprag clutch in the rear rim.

Originally Posted by aerohead

*The scoop itself may trigger separation itself.
*In a crosswind environment,the leeward side of the front wheel will be in turbulence,offering no useful ram air to the scoop,and affecting the pressure of air entering on the windward side.

That'd be a *good* thing, wouldn't it? It would effectively be two scoops side-by-side, so the downwind side shouldn't be affected much by the upwind side. The port scoop would exhaust to starboard, the starboard scoop would exhaust to port. The leeward shielding of the front wheel would prevent as much air from entering that scoop, thus most of the air is routed to the leeward side of the bike, lessening the effect of the side wind loading by the combined effect of lessening the torque the side wind creates on the bike (on the windward side) and by a counteracting torque (on the leeward side).

Originally Posted by aerohead

*NACA submerged inlets will convert velocity pressure to static pressure if you have an undisturbed pathway leading to the inlet.
*A Baumann scoop (NHRA Pro-Comp hood scoop) can reach outside the boundary layer and harvest the inviscid flow,with very low drag penalty,but needs an unimpeded approach for the air.
*As to the extractors,I recommend you look at Professor Alberto Morelli of Turin,Italy who was instrumental in the high-tech ducting of the 1978 Pininfarina CNR 'banana' car.He got the cooling system air to blend into the outer flow with zero turbulence.
*You will see that a reversed-NACA inlet is NOT ideal as an extractor.

Ah, got it. As you can see, aerodynamics isn't my area of expertise. But I can learn, and experimentation trumps all, eventually.

Originally Posted by aerohead

*The walls should be as smooth as possible to delay TBL transition.After that we just pay the man for the surface friction.There's no avoiding it.

Got it. Thanks.

Originally Posted by aerohead

*The challenge is WHERE to cite the extractors,since you'll be riding in a fluid battlefield with the goal posts moving all the time.Georgia Tech has been battling this for decades now.
In the future we may have active morphing body capabilities in which active surface sensors talk to the CPU and alter the shape,or porosity to deal with transient pressure domains.

My thinking is that reintroducing the air smoothly high and rearward (just before where the air starts to detach from the body) should add energy to keep the air attached, thereby reducing the size of the wake and thus drag. But again, experimentation will be in order.

Originally Posted by aerohead

I think you'll get a lot out of the books.

Got lots of reading to do. Thank you.

[botsapper]

A great additional resource; dedicated to scooter/feet forward motorcycles (initially Quasar) modifications/innovations. See the shared archival projects, recent, weird and conceptual ideas. Enjoyed their site!

FF Web | Feet Forward people do it Feet First

[Cycle]

An update. The hybrid ceramic bearings were delivered yesterday. Today I got one of the two needle bearings on the bike. So I'm waiting on one needle bearing to be delivered, and the return of the rear gears from MicroBlue Racing. Then I'll put the new rear gears in, put the new hybrid ceramic bearings in the rear gears, on the rear wheel, and in the front wheel, put it all back together and see how she rolls.

Once the new roller lifters, ceramic coating on the head, valves and piston, and metal surfacing on the new cylinder are complete, I'll tear down the engine and put the new hybrid ceramic bearings in there, as well.

After that, I'll be working on a new cam grind.

Still got to find a supplier for the Nuvinci Delta series CVT (Continuously Variable Transmission), in IVT (Infinitely Variable Transmission) format. If anyone has any leads, let me know.

[aerohead]

I did a response to your #11 permalink yesterday and it looks like the whole thing got lost into the ether.About an hours typing down the drain.
The long and the short of it is:
*it will require a wind tunnel to do what you need.It can't be done on the road.
*there is an online article about the E-Z-HOOK land speed record bike you ought to read.
*I would strongly encourage you to consider an 'open' bodied shell and modify your riding apparel to augment the streamlining,as Olympic downhill skiers are doing (Velcro foam fairings to your leathers).

[freebeard]

Always Select All and Copy before you click Post or Advanced. Always.

At an hour invested, I'd have Pasted into Stickies or some other text editor.

[Cycle]

An update on FrankenYager... the hybrid ceramic bearings are installed, the new taller rear gears are installed and worn-in, I've put 8.5 grams of 0.6 micron tungsten disulfide in the engine oil and 1.75 grams in the gear oil, I'm running a Pulstar HE1HT9 spark plug (which solved my cold rough idle problem completely), and I've installed a Wolverine 9.0 120 volt 125 watt 3" diameter block heater on the underside of the block, with a Westek TE06WHB digital timer with 20 timer events to turn it on and off... the Westek has battery backup that lets it go for months without being plugged in and it won't lose its programming.

I set the timer to turn on the block heater an hour before I go to work, and an hour before I'm off work. My average MPG over ~10,000 miles was ~65 MPG. The last fuel-up was 91.172 MPG.

That's without any other engine or aerodynamic modifications, so it should be pretty easy to reach my goal of 150 MPG once the engine mods, aerodynamic body and my inventions are fitted to the bike.

I'm going to be building a trellis frame for it, which will give me more room for my experiments and better mounting points for the new body, along with being lighter. It'll use a forkless front end for better handling.

[freebeard]

That's a good result.

How big a battery for backup, and how much does all that weigh?

The number of parts that originally shipped on the bike continues to dwindle?

[Cycle]

The timer itself is tiny. I can hold it in one hand, and it weighs only a few ounces. I'm not sure how big the internal backup battery is, but it needn't be very large, it's essentially a digital watch with programmable timers that trip a small relay inside. The relay only clicks if you've got 120 volt power, so the battery's not powering the relay.

And there's no need to replace the battery if you leave it unplugged for a long time, just plug it in. It'll recharge the battery.

The block heater is maybe a few ounces... it's a flat thermal film that has adhesive on one side. You clean the underside of the block, heat up the engine until it's too hot to touch, plug in the heater until it's too hot to touch, then stick it to the block and squeegee out any air bubbles. Then you plug in the heater for 15 seconds and squeegee it again, then do that a second time. Then when it all cools back down, you seal it up with silicone sealant around the edge of the heater. I applied a second thick coat of silicone sealant after the first one got tacky, and completely covered the block heater, so it's sealed up entirely and small road debris hitting the heater bounce off the silicone instead of putting holes in the heater.

The heater gets the block up to about 150 degrees F, so the engine doesn't have far to go to be at operating temperature.

I used a block heater that is larger than recommended... this block heater is recommended for oil pans of from 3 to 6 quarts. Mine is only one quart. I wanted to be sure it gets the block up to temperature. Once the heater hits about 150 degrees, its internal resistance rises and the amount of heat it produces drops until it balances with the heat loss of the engine.

[Cycle]

Another all-time high, both for fuel efficiency and miles-per-tank:
94.478 MPG
237.8 miles

The tungsten disulfide takes time to coat all the moving parts, so I think this improvement over the last tank is that. I haven't made any changes to the bike this tankful. I can do better... I couldn't resist opening her up for a 20 mile stretch.... perfect weather, perfect wind, the engine was running strong, and that throttle hand had a mind of its own. Heh.

So there's 20 miles on this tankful that were at WOT the whole way. Had I exercised a bit of self-control, the results above would have been a bit better.

[renault_megane_dci]

Wow.
That's a lot of money and work in a cheap scooter.
But anyway.

Could we have a glance at your fuel log ?

And pictures of the engine build, I like oily parts pics :-)