Towing with Electricity and a Model X

[SteveSueMac]

Originally Posted by Countryboy59

I'm gonna take a wild guess that Tesla is not aiming at the one ton truck market with their electric vehicle.

Not yet - but coming. See #52 in this thread...

[franklyfrank]

Originally Posted by SteveSueMac

Not yet - but coming. See #52 in this thread...

Competition benefits all of us. However it has to earn market share on its own merits without government involvement.
We spend plenty of research dollars already to help make new technologies commercially viable. We shouldn't be subsidizing the entrepreneurs.
I personally wouldn't have patients to deal with the restrictive issues , short range, long recharge time etc.etc. to get involved with towing with an EV. I believe they are a great Idea as a second urban car where it can be plugged in overnight but that of course is my personal opinion and we all know what that is worth in the real world.

[SteveSueMac]

Everyone's entitled to their opinion, Frank 😀

Personally - I'd love to see Tesla build a train-like hybrid diesel/electric truck (where the Diesel engine charges the electric) for towing. Talk about purpose driven vehicles!

[Glenritas]

Diesel /electric is nice but so old school .
That said, the market already has a small gas turbine engine that would be a great choice to drive a generator.
I think it is currently being used as a turbine / electric to power some systems.

As for me I finally got a Kia Soul EV to give my Scion XB a rest. The best part is I haven't had to buy gas for it for all my local running around

Now if I want to leave town I have several other ICE choices to use.

If I want to pull a trailer I have 3 TV's to choose from.

Opp's , am I starting to sound a bit pretentious?

I guess it just boils down to the right tool for the job.

[Countryboy59]

Originally Posted by franklyfrank

Competition benefits all of us. However it has to earn market share on its own merits without government involvement.
We spend plenty of research dollars already to help make new technologies commercially viable. We shouldn't be subsidizing the entrepreneurs.
I personally wouldn't have patients to deal with the restrictive issues , short range, long recharge time etc.etc. to get involved with towing with an EV. I believe they are a great Idea as a second urban car where it can be plugged in overnight but that of course is my personal opinion and we all know what that is worth in the real world.

If you're working they make great sense. Everyone has to commute. And the technology is creating a whole bunch of very good jobs. There are quite a few places in my area making parts for Tesla (not to mention a few others).

I'm one of the exceptions, commuting in my Superduty, but hats off to technology and progress!

[jcl]

More on a potential Tesla pickup:

http://www.teslarati.com/electric-tr...s-master-plan/


And information on the Wrightspeed range-extended electric truck drivetrain.

http://www.wrightspeed.com/

Exciting times.

Jeff

[ohmman]

To try to get a little back to the intended topic, I am spending a little time looking at my hitch setup. I understand that closing the gap between the TV and TT can make a big difference in aero drag. Given that range is one of my top concerns, and that aerodynamics are the biggest drag factor, I figure that attention to this location could provide fruitful.

Currently I see the indicated "extra" space in my hitch setup (photo below). I realize I will have to make sure that I can fully articulate without contact, but I was curious if some of the experienced members here could take a look and let me know if a custom hitch setup might be worthwhile.

[kscherzi]

At Can Am Andy's recommendation I had a second hole drilled in my Equal-i-zer hitch shank to snug it close as possible to the vehicle reciever. The purpose is to minimize overhang past the rear axle. Every little bit helps. I slid mine back all the way and traced the hole outline with a penciled. Any decent RV or machine shop ought to knock it out for you.

[markdoane]

I drilled mine out to gain about 3 inches. More for getting the hitch ball closer to the rear differential than for any aerodynamic benefit. Minimizing overhang helps greatly, especially if you have a short wheelbase.

Any side force applied to the hitch ball will cause a yaw force around the rear axle. Not a big problem if the front tires have sufficient adhesion, but if you add up worn tires, slippery roadway, poor weight distribution setup and a short wheelbase you are more likely to have a white knuckle experience.

[rostam]

Originally Posted by ohmman

To try to get a little back to the intended topic, I am spending a little time looking at my hitch setup. I understand that closing the gap between the TV and TT can make a big difference in aero drag. Given that range is one of my top concerns, and that aerodynamics are the biggest drag factor, I figure that attention to this location could provide fruitful.

Currently I see the indicated "extra" space in my hitch setup (photo below). I realize I will have to make sure that I can fully articulate without contact, but I was curious if some of the experienced members here could take a look and let me know if a custom hitch setup might be worthwhile.

The closer the ball is to the rear bumper, mathematically, its better. The idea is to have a smaller rear overhang to wheelbase ratio. I don't have 40 years of towing experience (just 2), but I could not tell any difference in towing dynamics when I used different sized shanks (One was maybe 2 or 3 inches longer than the other).

I'm a numbers person, and decided to run some numbers. Picked Expedition EL as my example TV. Got these numbers from Ford.com:

Wheelbase: 131"
Rear overhang: 51.1"

Lets say you want to compare rear overhang to wheelbase ratio for two different setups. One uses a 10" long shank, the other uses a 12" shank. Shank length gets added to the (overall) rear overhang, hence we have

For 10" shank:
Rear overhang / wheelbase = (51.1" + 10") / 131" = 61.1" / 131" = 0.466

For 12" Shank:
Rear overhang / wheelbase = (51.1" + 12") / 131" = 63.1" / 131" = 0.481

Change percentage: (0.481 - 0.466) / 0.481 = 0.015 / 0.481 = 3%

A smaller rear overhang to wheelbase ratio is better. Going from a 12" shank to a 10" inch shank caused a 3% improvement in the ratio. Not much.

I did not notice any improvement. Some seem to experience miraculous improvement (I have a hunch thats partly how they "feel" rather than what they really experience). Hitch companies usually sell shank at different lengths (8", 10", 12", etc). See if your hitch company sells a shorter shank and give it a try. BTW, personally, I would not drill a hole in the shank to shorten it.

[rostam]

Another note: reducing the shank length, reduces the effectiveness of weight distribution, as the lever arm is shortened.

[jcl]

Originally Posted by rostam

Another note: reducing the shank length, reduces the effectiveness of weight distribution, as the lever arm is shortened.

Not by the 3% figure in your example though. The moment arm is to the front axle, so closer to 1%.

[rostam]

Originally Posted by jcl

Not by the 3% figure in your example though. The moment arm is to the front axle, so closer to 1%.

Right, I just got tired and did not calculate that

[SSquared]

I got my hitch from Andy at Can-Am. The shop did drill a new hole and cut off the end. They even cut off a portion of the triangular gusset material. I did not drive the rig with the un-modified shank so I can't compare the before and after feel.

By the way, with my rig, when I turn sharply, the thing that goes crunch is the friction bar on my EAZ lift hitch; not any car or trailer sheet metal. My tow vehicle has a small enough turning radius that this happens on a tight U-turn in the forward direction. How tight is the turning circle of your car? Can you freely do a tight U-turn or traffic circle loop?

[ohmman]

Thanks, as always, for the informed responses. I recognize that there are some handling and vehicle stress benefits from reducing the shank length. I certainly welcome those, but the driving factor was the purported aerodynamic benefits. Because those are so uniquely tied to the TV-TT combination, I don't expect that anyone will have excellent data on how much or how little it'll help. However, I'd love to hear your anecdotes. Extra thanks to rostam for the numbers. I'm very much into the numbers as well. I prefer to know whether something helps vs. whether I feel like it helps. The placebo effect is lost on me, for better or worse.

Originally Posted by SSquared

My tow vehicle has a small enough turning radius that this happens on a tight U-turn in the forward direction. How tight is the turning circle of your car? Can you freely do a tight U-turn or traffic circle loop?

The Model X turning circle is 40.7'. It's not wide, but it's certainly not tight. I'm guessing that'll make it less of an issue with the articulation concern.

[markdoane]

The "miraculous improvement" I've noted from shortening the shank is more in the neighborhood of 6%.

While I didn't call it miraculous, anything that costs me nothing and makes an improvement in safety is welcome.

[jcl]

My anecdotes on fuel consumption reductions related to tow vehicle/trailer gaps are in reference to on highway Class 8 trucks. The attached report may provide some data that can be transferred to SUV/Airstream gaps, at least for order of magnitude estimates.

https://www.tc.gc.ca/eng/programs/en...-eng-2939.html

Jeff

[Nuvite-F]

As noted previously, reducing the distance from ball to tow vehicle rear axle reduces the moment arm of the sway-producing couple, so it is a worthwhile thing to do.

I doubt you will see much if any reduction in drag because the frontal area of the trailer is much greater than that of the tow vehicle. If you were towing with a van, you might notice a difference.

Lastly, do check all clearances before making this change. I tow with a half ton pickup truck and if I shortened the hitch any I wouldn't be able to open the tailgate of the truck with the trailer attached, a distinct inconvenience.

[rostam]

Originally Posted by markdoane

The "miraculous improvement" I've noted from shortening the shank is more in the neighborhood of 6%.

While I didn't call it miraculous, anything that costs me nothing and makes an improvement in safety is welcome.

Just to clarify, my comment was not in regard to your post or any other member who posted in this thread.

I also agree that a shorter shank is better and suggested OP pursue this route. Just wanted to share my calculations on the expected improvement.

[ohmman]

Originally Posted by jcl

My anecdotes on fuel consumption reductions related to tow vehicle/trailer gaps are in reference to on highway Class 8 trucks. The attached report may provide some data that can be transferred to SUV/Airstream gaps, at least for order of magnitude estimates.

https://www.tc.gc.ca/eng/programs/en...-eng-2939.html

Jeff

Great document, and thanks for posting. It was enlightening to learn that the dominant factor in drag reduction due to the distance between the TT-TV is related to the yaw created by continual adjustments on the roadway. At least, if I'm reading it correctly, that's what I see.

It also brings up "platooning" which raises an issue that I should probably address here. The hypermilers among us might point out that we could draft semis. That's possible, and within some reasonable distance, I think the evidence shows an increased range/decreased consumption. At some point I may be willing to do that within a safe following distance and using TACC on my vehicle. But generally, I'd like to set up my rig so that it's in the absolute best condition on its own. So I'll exclude that for now from my analysis and experimentation.

Thanks again for the informative link.