Economy/performance estimates on the 3VL-TWN (trike)

[rodekyll]

I ran my fuel tanks dry.  Two 5-gal Gerry cans.  I got almost exactly 300 miles in Sitka driving (town speeds with occasional bursts to highway speeds).  So that's 30mpg pushing 1100# with no transmission.  I think it will do better on a long trip, so I'll make 300 miles my range.  30mpg is about 5mpg less than the same engine with the Convert drive train and 2 wheels, fully loaded for x-continental travel.

Top speed so far is +80mph with throttle to spare.  70mph cruise speed seems very reasonable -- chassis is firm and ride is stable at those speeds.  Accel from stop is about like my gmc van -- you can step out if you want to make a racket, but it's happy moving along with other traffic.  I have made one pass of a slower vehicle.

Low end grunt is TBD, since so far nothing Sitka has to offer has discouraged it.  We have a few hills, but no real distance to them.  Engine and ATF temps are unremarkable under all conditions so far.

Rear brakes still suck.  I think I should be able to lock up the rear wheels, but it's just not happening.

Alternator is putting out 14.7vdc @8mph, assuming otherwise charged battery.

Handles wet roads and rain just dandy.

Today's project is soft-mounting the floorboard surfaces.

[Chuck in Indiana]

Thanks for the update.. nice project.

[Antietam Classic Cycle]

 

[rodekyll]

I forgot to mention that it passed the egg test, too.  That's where you go to the store, buy a dozen eggs, set the carton in the open cargo bed and drive out the Nelson Logging Road to the rifle range.  It's about 6 miles of rough logging road with two bridges.  The bridges are timber cross ties with planks laid for normal cars -- trike doesn't fit. so it's like running down a rail road bed.  Then I ran it out to the other end of the road for another 6 miles of no road.  I got all the eggs home unbroken.

[Chuck in Indiana]

Well, I would say that is the ultimate test. My old rig would have made a crunchy omelette. 

[Sheepdog]

A singular design...I really like both the style and the utility. Far better than those Gold Wing/Electra Glide-derived trikes.

[Zoom Zoom]

I'm pleased to hear things are working out for you. I remember the rear end ratio was some concern during your planning stages.

 

John Henry

[rodekyll]

The final drive ratio was the single most critical calculation in making the concept work.  I'd originally intended to use a Nissan R200 (240zx) rear end which has a natural 4.9-ratio gearset choice.  My second choice was one of the larger Ford diffs that have a good selection of ratios from 4.88 - 6.xx.  When it was all over though I'd settled on the Ford 7.5" punkin, mostly because it came in a salvage lot I bought, but also because of it's relatively small size and weight. 

Here at WG the math geniuses worked me through the various reduction factors and arrived at a high-range raw figure of about 4.64.  I felt that I needed to be a bit lower than that -- 4.88 would be ideal.  That's available for 50# more weight and a corresponding increase in bulk if I used a Ford 9" punkin, but the large size put me off, and an IRS version of the differential was cost prohibitive.  The 7.5" diff doesn't have 4.88 available, but the 5.11 seemed to also be a viable option, as it falls between the Convert's natural low and high ranges (closer to high range). 

And that's where it ended up -- 7.5" Ford IRS diff with 5.11 gears.  So far it's adequate on speed and mild on performance.  The torque converter is doing good duty as both the clutch and the gear reduction.  The punkin is buried deep in the chassis.  If it does turn out to be wrong, the project is a failure and I'll have to redesign the entire thing -- except I won't.