VEXpro 2015 Product line launch

[Taylor]

Sorry, uninformed NEM question here:
What does the ThunderHex do that Churro doesn't? I see that the aluminum is 7075 rather than 6005, which I presume makes it stiffer. But why is it 2x the price? Is that just the nature of the alloy?

[s_forbes]

(meandering a bit off topic)

Originally Posted by AdamHeard

Modeling a round tube conservatively at .5x.201 I get 97.4% the bending stength.

For those curious why the hole makes little difference to the bending strength, check out the list of second moment area of inertias for different shapes. For two axles of the same diameter, the second moment area of inertia is proportional to the amount of bending load it can withstand. The r^4 term is what makes the small hole have little effect on the bending strength of the axle.

My napkin calculations put the ThunderHex axle (with the hole) at about 46% stronger (in bending) than a solid 7/16" hex shaft of the same material.

[Mr V]

Originally Posted by AdamHeard

We have no issues teaching kids to do either of these... It's standard practice on our team and kids do both all the time.

I guess it must be the students on our team but we don't haven't had that many that are interested in using the lathe let alone becoming competent in using it. We do however typically have one student that quickly decides it is his or her favorite machine and does become quite competent. Of course when you need something right now that student seems to be absent that day.

[FrankJ]

Originally Posted by Taylor

Sorry, uninformed NEM question here:
What does the ThunderHex do that Churro doesn't? I see that the aluminum is 7075 rather than 6005, which I presume makes it stiffer. But why is it 2x the price? Is that just the nature of the alloy?

As far as stiffness goes, All aluminum has pretty much the same stiffness. Stiffness is based on Young's modulus, shape & doesn't change much with alloying & heat treatment. Strength is a completely different story.

The concern I would have would be the difference in torque transfer of a rounded off hex & would the shape spin in a round bearing, making it a bushing. I have not looked very closely at this so it is just a concern, not an known issue.

[AllenGregoryIV]

Originally Posted by Taylor

Sorry, uninformed NEM question here:
What does the ThunderHex do that Churro doesn't? I see that the aluminum is 7075 rather than 6005, which I presume makes it stiffer. But why is it 2x the price? Is that just the nature of the alloy?

Churro tubes aren't designed to be used as axles. I've seen a few teams do it but they often bend them. Thunderhex has the strength of the VEXpro hex shaft but also have the through-hole and rounded corners to be used in a specific round bearing (13mm).

We used VEXpro tube axles last year for through-bolted spacers and Churro tubes for tapped standoffs. A few times we had to drill and tap hex shaft when the churro tubes weren't strong enough for our application. The thunderhex should fix this. We can also use #10 through bolts with the Thunderhex and since we are also a #!0 team that will make some things easier.

[Taylor]

Originally Posted by AllenGregoryIV

Churro tubes aren't designed to be used as axles. I've seen a few teams do it but they often bend them. Thunderhex has the strength of the VEXpro hex shaft but also have the through-hole and rounded corners to be used in a specific round bearing (13mm).

Cool. What about it gives it the added strength? Is it the cross-section geometry? The alloy? The black anodizing?

[AllenGregoryIV]

Originally Posted by Taylor

Cool. What about it gives it the added strength? Is it the cross-section geometry? The alloy? The black anodizing?

The alloy, 7705 is a zinc alloy and in general 7xxx series aluminum (zinc alloys) will be stronger than the 6xxx series which are magnesium - silicon alloys.

[Monochron]

To any Vex employees:

If we are ordering new Talons or Victors, should we put in a separate order for additional parts if we want to have the additional parts delivered quickly? I know the Victors/Talons aren't shipping immediately I don't want the rest of my order waiting for them.

I ask because Andy Mark's site recommends that you put SPs/SRX's in a different order than you would other materials.

[RonnieS]

What are people getting more of, talons or victors? I'm going to assume mostly victors because of the price but I could be wrong. Also, what helped you decide what to get.
-Ronnie

[Joey Milia]

Originally Posted by Taylor

Cool. What about it gives it the added strength? Is it the cross-section geometry? The alloy? The black anodizing?

It's definitely the black ano!

No jk. It's mostly the alloy. 7075 has over twice the tensile strength of 6005. (Based off of strengths I found here http://alcobrametals.com/guides/aluminum) I think the cross-section of the thunderhex is also stronger but that probably has a smaller impact than the alloy.

(And Allen beat me to it...)

[AllenGregoryIV]

Originally Posted by Monochron

To any Vex employees:

If we are ordering new Talons or Victors, should we put in a separate order for additional parts if we want to have the additional parts delivered quickly? I know the Victors/Talons aren't shipping immediately I don't want the rest of my order waiting for them.

I ask because Andy Mark's site recommends that you put SPs/SRX's in a different order than you would other materials.

You probably should just call VEX sales, instead of reposting the same thing. They will help you out.

Originally Posted by Ronnie314

What are people getting more of, talons or victors? I'm going to assume mostly victors because of the price but I could be wrong. Also, what helped you decide what to get.
-Ronnie

The Talon SRX and the Victor SP are mostly the same product - they were designed in tandem by CTR and VEX. The only difference is that the Talon SRX is CAN capable, whereas the Victor SP only uses PWM. As a result the Talon SRX is negligibly larger, and costs about $20 more. For those who do not use CAN in their electronics, the Victor SP is probably their best bet, saving them $20 per controller, and for those who do use CAN, the Talon SRX is a godsend compared to the Jaguar, and well worth the money.

EDIT: Michael Hill covers some aspects of the Talon SRX that I had missed earlier in his post right after mine.

[Michael Hill]

Originally Posted by Andrew Lawrence

The Talon SRX and the Victor SP are mostly the same product - they were designed in tandem by CTR and VEX. The only difference is that the Talon SRX is CAN capable, whereas the Victor SP only uses PWM. As a result the Talon SRX is negligibly larger, and costs about $20 more. For those who do not use CAN in their electronics, the Victor SP is probably their best bet, saving them $20 per controller, and for those who do use CAN, the Talon SRX is a godsend compared to the Jaguar, and well worth the money.

The SRX also has SPI, USART, and on-board closed-loop PID control

Originally Posted by Michael Hill

The SRX also has SPI, USART, and on-board closed-loop PID control

I was unaware. You learn something new every day. Thank you for the additional info, Michael.

[Monochron]

Originally Posted by Andrew Lawrence

I was unaware. You learn something new every day. Thank you for the additional info, Michael.

As well as a master-slave mode that the Victor doesn't.