PSRU

Discussion in 'Supplier / Manufacturer Announcements' started by 1946, Oct 2, 2010.

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  1. Nov 1, 2010 #41

    autoreply

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    Just for your information; if a manufacturer isn't willing to answer the single most important question (that rips apart most/all PSRU's on the market), that could say something about their knowledge and skills.

    As for communications; after my post above I got a pretty insulting (unfounded) message from this seller while he refused to respond to questions I asked in my last post in this topic.

    I urge everybody to think for their selves and wonder; "Would you bet your life on somebody who gets verbally aggressive if someone asks the single most important question about his product?"
     
  2. Nov 1, 2010 #42

    DLrocket89

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    I was just asking because titanium gears are the single stupidest idea I've heard in awhile (I'm a metallurgical engineer working in aerospace for what it's worth).
     
  3. Nov 1, 2010 #43

    autoreply

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    Well, your post reminded me that I still wanted to respond to his last "message" ;)

    Can you elaborate on why titanium is such a stupid idea? (Just curious)
     
  4. Nov 1, 2010 #44

    DLrocket89

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    It has the wear resistance of bubble gum. You'll gall everything into oblivion.
     
  5. Nov 3, 2010 #45

    1946

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    Untreated, Ti has poor wear capabilities; we are still testing the best anodizing/oxidizing and other coatings available to make it wear resistant.
    Thanks
    Albert
     
  6. Nov 3, 2010 #46

    autoreply

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    Thanks DLRocket for the explanation. They're apparently doing the impossible in just a redesign...
     
  7. Nov 3, 2010 #47

    jhausch

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    I posted this in the Form over Function area (a very interesting thread about not using a re-drive).

    I don't know much about the inner workings of these, but why not use or copy the gearset in a GTSIO-5__? Maybe a "double pass" of that gearset if you need more reduction. . .
     
  8. Nov 5, 2010 #48

    DLrocket89

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    What happens when the coating wears through or breaks off?

    Anodize is a brittle ceramic-like coating that will chip and flake off, you've gained nothing. Most other coatings that are wear resistant are also brittle and suffer the same fate. Some happen quickly, some slowly, but it happens.

    Sure as heck don't want to be on final when it happens.
     
  9. Nov 5, 2010 #49

    greywuuf

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    Also it is my( granted uneducated) understanding that the base "strength" of Ti is only relatively high when compared to weight. Based on cross section it fairs comparatively worse than steel. Said in another way in a part where your size is constrained say a 1/2" axle that a steel axle will be "stronger" but the ti part will weigh roughly half as much. This is coming from 'conventional wisdom" in the Bicycle industry.. so I do not know nor have I looked up the relative compressive tensile or any other numbers of Ti, but it seems to be born out by my personal experiences with Bicycle crank axles. you do not go to Ti to make stronger or tougher products you go to Ti to make lighter products ( and to sound sexy to consumers )
     
  10. Nov 5, 2010 #50

    1946

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    Using Ti gears and boxes casted in Magnesium and Carbon Fibers isn’t about to make it sound sexy (greywuuf) or taking the risk the coating wears off (DLrocket 89) but is all about weight reductions, the performance of surface engineered titanium PSRU gears can be successfully predicted thus making possible the design of optimized surface engineering systems to meet particular engineering demands within the shortest possible time and with least cost ,with innovative surface engineering technique, multi-layered surface contact treated titanium gears have satisfactorily completed rigorous testing’s and have successfully improved the tribological behavior of titanium alloys in terms of low friction, high wear resistance and high resistance to scuffing.
    Thanks
    Albert


     
  11. Nov 5, 2010 #51

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    Do you realize CFRP is horrible at impact loads (vibration). Even in formula 1, they're just starting to be able to use a CFRP gearbox. So you're actually using Ti to save a couple of ounces and then it's up to the customer to suffer when the gears are worn down after a week. Geez...

    This is nothing more than a scam.

    You've nicked the whole design from someone else, which makes you a thieve. That's theft, but ok, it is ok from your moral perspective. I guess you don't mind that we judge your moral attitude and extend it to customer relations then? Then you've changed a couple of things. Apparently you don't have the slightest clue what you're doing, given the remarks by more knowledgeable people here. You refuse to answer the most elementary questions that would be asked about EVERY PSRU. You start personally assaulting people with quite offensive acquisitions if they ask straight and objective questions, you don't answer.


    Why do I post this? We frequently get people here that feel like they're scammed or stolen from, they only found out too late that the business they're going to isn't thrustworthy. Given this guys representation on the internet, I guess several people are going to fall in his trap as well and I hope to give people at least some thought, based on the above statements. I've given this guy several opportunities to answer questions (2nd and 4th line of my text), but he refuses to.

    I hope the mods won't delete this text, since I don't think there are any offending or unjust statements in it and I think it can serve an important goal of this forum; to inform people about these kind of things. I really hope to prevent a Hart-Aero-like thread about this guys business.
     
    Last edited: Nov 5, 2010
  12. Nov 5, 2010 #52

    Topaz

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    Which is marketing-speak for, "...cheaper for us to get into production and sold out the door, and we'll take a lot of risks to do it."

    If it falls apart in-service, well, hey, you've made your sale, right?

    Sorry, guy. You can't kid a kidder.
     
  13. Nov 5, 2010 #53

    DLrocket89

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    I know, it's just fun to push buttons from time to time... :gig::whistle:

    I work as a materials engineer at a company that makes generators, gearboxes, and other large parts for commercial and military airplanes. We also make the gears that go inside. This whole thing (from what I've seen) is crap. Cast Mg isn't, but I don't see how cast Mg help you...yeah, the density is low, but so is the strength...your "specific strength" is lower than aluminum by quite a bit. The only way it helps you is if you're too strong with aluminum but can't reduce your cross sectional size any.

    Not only that, now you have one giant galvanic cell set up between the PSRU and whatever you bolt it to, and the PSRU is going to be the part that corrodes into oblivion. Isn't electrochemistry a b!tch?



    1946 - One of my areas of work is tribology, in particular with gear and bearing materials. I run the wear test lab for our corporation, in addition to a lot of the mechanical testing (including gear fatigue testing). I would love to see your wear resistance data (not vague, unsubstantiated "satisfactorily completed rigorous testing’s" [sic] claims). Show me the data...if I'm going to put my life on the line with my product, you can provide that to me.


    As it happens, I'll be in the market for a PSRU for a build in the next couple of years, so please enlighten me.
     
  14. Nov 5, 2010 #54

    macdonca

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  15. Nov 5, 2010 #55

    1946

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    Not only that, now you have one giant galvanic cell set up between the PSRU and whatever you bolt it to, and the PSRU is going to be the part that corrodes into oblivion. Isn't electrochemistry a b!tch

    Volkswagen Passat's have magnesium gearboxes housing for aluminum engine blocks, and nobody is *****ing about corrosions, strength or electrochemistry.

    As it happens, I'll be in the market for a PSRU for a build in the next couple of years, so please enlighten me.

    About pushing buttons, cooks: they never disclose the ingredients, if and when ready to buy a PSRU it will be served with all relevant data. In the mean time, just the aroma is available. :lick:

    Thanks
    Albert
     
  16. Nov 5, 2010 #56

    DLrocket89

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    VW's mag/aluminum interface is true, but have you ever looked under a car? The frame and engine and stuff corrodes a LOT, and that's OK because they plan for it. Does your stress analysis (which I hope you did) account for a pit 1/2 the total thickness of the part? In particular, this will happen where you have bolts (which happen to be the highest stressed area of the part).

    Regarding the other part, they typically require an ingredients list on food...if I don't see the ingredients, I don't buy it. Perhaps it's different in your part of the world, but here I know what I eat. I also know what I bolt onto my airplane.
     
  17. Nov 5, 2010 #57

    greywuuf

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    only the aroma is available ? I know what that particular aroma is ;)

    Sounds an awful lot like "Selling the Sizzle, not the steak"
     
  18. Nov 5, 2010 #58

    Topaz

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    And terribly done, at that. Someone needs to learn how to do social network marketing.

    Rule #1: Don't argue with your customers.

    Ask Nestle how arguing with your customers online turns out... :speechles

    Some tips for you, Albert.
     
  19. Nov 5, 2010 #59

    PTAirco

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    Playing devil's advocate here; original VW crankcases have always been magnesium castings. I know there are aftermarket aluminium ones, but the originals all were a magnesium alloy.

    (Ten years in the USA and I still can't bring myself to say or write "aluminum"!)
     
  20. Nov 5, 2010 #60

    DLrocket89

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    Agreed. I'm not saying it's impossible to bolt mag to aluminum, just that precautions need to be taken (either in allowing for corrosion or in preventing the corrosion).
     

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