Motor Pod rear attachment?

[johnhead]

Group.. I'm concerned that I don't see an attachment from the rear "Motor pod" to the Main body of the V1? I wouldn't think the engineers would use a front only attachment for the tilting mechanism?. That appears to be a large amount of load to be attaching to just a single (front) mount? What am I missing?

[cpaddock]

At this point, I don't think any of us knows or isn't saying....you are right about the loading issue and this thread has been hashed to death at FTR.com.....all speculation.
My guess is some sort of tube/shaft that runs under the pod and thru the pivot point.
But I'm not the engineer here and imagine they are giving this critical area due consideration. But I'm with you and would sure like to know "How's it work?" :)
Aloooooha!

[Derwin]

johnhead,

Everybody has to remember that Venture Vehicles is not trying to re-invent the wheel here. The tilting technology is what they purchased the rights for from Carver in Europe. I think they will be using the same system that they use, with maybe a few alterations. You can check out the Carver engineering website to get all of the details. There is some pretty amazing stuff there! Go to:

http://www.carver-engineering.com/technical/dvc.html

Derwin

[cpaddock]

Actually, the mystery stems from the "no rear pivot" controversy which has not been
clearly settled. All the technical papers have been extremely informative but I have yet to see a single schematic of the main pivot system/mechanicals. And since the V1
clearly has no rear pivot, they have to be in uncharted territory to some extent. IMHO

[Derwin]

How is Carver doing it now? They seem to have a very stable vehicle on the market. I just checked the Carver engineering site, and I couldn't find any details. If any of you find anything, please post it here for all to see! Thanks.

=y:

Derwin

[johnhead]

Yes the carver clearly shows an "inverted triangle" that attaches to rear of the pod..The V1 shows no such rear attachment point?

[rogwild]

Yes, 'johnhead', the attachment on the production Carver One is obvious; but is it 'structurally required' or just cosmetic? The Carver One operational prototype does NOT have the rear triangle, nor do some of the 'future concepts' diagrams in the Carver literature.
It would be interesting to know the 'TRUE' reason before the V~1 goes into production. I just hope the Vv engineers were astute enough to 'talk' to their Strategic Partners at Carver, before they finalized their design.

[RAN]

The V-1 is being designed so that the power pod will break away in an accident. I would imagine that is why they did away with the outer rear mount. It's still possible to have the pivot supported throughout the inside of the pod.

[johnhead]

I just saw Ian's latest update and he showed a welded frame from the "prototype" V1..It only has a single small (in my opinion) connection to the power pod from the main body..I hope I'm missing something.. That's a lot of load at a single connection point. This point will carry torsion,compression, tension, and shear forces ... Any other "engineering" types notice this?

[Mike kZ]

Does anyone know why it's designed so that the power pod will break away in an accident? So if you are side swiped in the rear, you are going to be sliding on your side in the front cockpit! That doesn't sound very safe:o

[cpaddock]

Yeah, the photo certainly leaves room for interpretation, and Ian DID say "Don't read too much into this".....nevertheless, inquiring minds will continue to speculate. It appears to me that this is a very strong arrangement. The pair of rods which are bolted to the rear of the cockpit come together on a substantial tube built into the base of the motor pod.
They would be welded to a sleeve which would connect to an inner rod which returns to the cockpit base, resulting in a triangulated strut system. Secondary motorpod triangle
struts serve to transmit loading to entire pod frame. As far as break-away is concerned,
I don't see how you could make it strong enough to avoid this. Especially in the head-on
side swipe scenario having the pod go away and take the impact forces with it will be your best hope of survival. IMHO. Also, rear wheel steering struts are just laying on the assembly table, presumably in the approximate location of function. Connectivity is still
not clear to me. Tilt action could be the driver, but the main steering rod could come all the way back through the tube to be the activator. I did find one sentence in DVC tech
paper which mentioned rear wheel steering function related to high speed turning/power
useage. I would still like to see conclusive info on slow speed action (parking, etc.) re rear wheel steering
Aloooooha!

[rogwild]

Just because it is designed to break-away to dissipate energy in a crash, does not mean that it will separate into two pieces. Many Formula One racers have break-away parts (such as the wheels/tires) that are tethered to the main body.
I would imagine that the engineers would design (and TEST) the connection/pivot point to withstand minor impacts (and normal driving forces), but that would shear off in major collisions that otherwise would deform the 'roll cage'.

[RAN]

I think it'll be designed to break away in certain types of accidents, say getting rear-ended, to prevent the power pod from intruding into the passenger area. In those cases, breaking away also absorbs some of the energy of the collision.

[WarpedOne]

I would still like to see conclusive info on slow speed action (parking, etc.) re rear wheel steering

Carver does rear wheel steering above 100kmh or 60mph, below that it only does front wheel steering and tilting.

[cpaddock]

Warped 1, any chance you could share your source? Just seeking a deeper understanding...
Mahalo....(Thanks)

[MVRacing]

"Yeah, the photo certainly leaves room for interpretation, and Ian DID say "Don't read too much into this".....nevertheless, inquiring minds will continue to speculate." ... cappadock

Absolutely agree. This is just the Alpha mule -
"-- we're "only" using it to test propulsion, suspension, strength, driving dynamics, and handling. The Beta spaceframe will be much closer to the final production chassis." .. Ian.

So a bit of speculation on my part - -
The pivot point looks plenty beefy to me ... I still believe the rear point on the caver is not for structural support.

I think the small round tube (2" x 3/4"?) at the end of the square tube forming the forward lower edge of the pod is the attachment point for the hydraulic tilt pistons (1 each side). For the pod attachment point, I imagine a bracket in front of the pivot point where the red cardboard and duct tape is now.

Break away will depend on the specifications of the attaching hardware for the tilt pistons, and the two struts triangulated up to the bar at the base of the floor pan.

I am a bit surprised at what they already have welded up for lower A frames. Would like to see how they plan to do the rest of the suspension! I would have use a lower A frame (pictured below) like this. All 3 attachment points use a rod end. The single one at the top of the A allows camber adjustment, while the other 2 control track, castor, and toe (to some degree - depends on the rest of the suspension design).

At any rate, it will be fun to watch this develop, then see how it translates in the Beta design.

I just hope Ian continues to share!! =y:

[WarpedOne]

Warped 1, any chance you could share your source? Just seeking a deeper understanding...
Mahalo....(Thanks)

Sure, here it is on page 4: http://www.brinkdynamics.com/_downloads/brink_AVEC_2004.pdf (http://www.brinkdynamics.com/_downloads/brink_AVEC_2004.pdf)

[johnhead]

WarpedOne..Thank you for this link. It is great reading. Now i just need the time to study it closely enought to put all the pieces together...I want to be able to describe how MY V1 functions to all my MOTORHEAD friends..

[MarkH]

After I get mine I can see having to carry around info packets and handing them out every time I stop for gas, stop at a traffic light, stop at a stop sign, get pulled over 'cause the cop wants to ask me about "what the heck is that?", well basically every time I stop...

[johnhead]

I visited the Carver site and downloaded their earlier data on DVC.. It did show their frame with a front and REAR attachment point. Can anyone tell me if the current Carver model has this dual attachment point? After looking at the prototype V1 frame, I am still somewhat concerned at the single front attachment concept between the power pod and main cabin.

[WarpedOne]

I am still somewhat concerned at the single front attachment concept between the power pod and main cabin.

Do you have similar concerns regarding truck wheels? They have single attachment point also...

;)

[johnhead]

Naa they are held by an inner AND out bearing.. half of the front pod on the V1 is supported by the front wheel however the rear is attached to the power pod by a single pivot pin. (and two hydralic cylinders). More concerned about the flexing of this point as I'm CARVING through the Twisties.... I still think the CARVER has a front and rear pod attachment point. If this is not currently the case... let me know and I'm satisfied.. I'm not that hard to please.. JUST hurry and build MINE! ;-)

[dhartman]

Vehicles that use concept 2 include, for example, the "GM Lean Machine" dating from 1983, the "Carver" from Vandenbrink and various scooter-type vehicles from Honda, including the Honda Gyro / Honda Stream dating from 1984. There has been a BMW concept on this basis in the BMW Museum in Munich since 1991.
In addition there is an incredible number of DIY solutions and one-off builds, very small manufacturers, design studies, university projects and ideas from car manufacturers.

Tilting technology:

The CLEVER vehicle is a cabin tilter (1F1T). The cabin with the front wheel is connected to the power unit and the two rear wheels by a pivot bolt. The rotary movement of the cabin is produced by two hydraulic cylinders (actuators) that are installed between the cabin and the power unit.


My take: A titanium pivot bolt?!?!

for a great web site and more infor go to www.clever-project.net (http://www.clever-project.net)

[johnhead]

Shows a round "pivot" like receiver welded to the lower REAR section of their bare frame. I guess a single very strong pin that attaches to the rear and front of the "power pod" will suffice for me.... =D

[Mark Tomlinson]

Another thing to consider is that Ian and Venture intend to crash test the thing. That and durability testing (driving for weeks on end on cobblestones) should tell us whether the single connection point is strong enough.

Point well taken, though. I'd hate for the connection point to become Venture's Achilles' Heel, much like Tesla Motor's transmission. If you follow Tesla you'll know that the transmission problems turned up late in the design and caused multiple delays and downgraded performance. Best to catch such issues early in design.

[cpaddock]

You guys are still ignoring the two struts which pivot with the cockpit with and triangulate, i.e. make a three point connection to the rear of the cockpit, thus spreading the loading forces over a much wider area. In this way they can work in concert under normal stresses, but shear more easily as smaller individual units in case of impact loading. The lower, horizontal pivot rod which runs inside central motor pod cylinder
would have multiple bearing points and serves to keep the pod properly aligned, therefore the collapsing effect is canceled out by virtue of the fact that this down-force
is placed over/near the rear wheel hub centers via those pivoting diagonals. IMHO :)

[wa3wheels]

As a option ..........

A trailor hitch to pull a 20 cubic foot motor cycle trailor.

[johnhead]

NOW don't get me started again... a trailer hitched to the rear pod would only add to my concern! You know how I get.....