Redrives for most commercial engines.

Discussion in 'Supplier / Manufacturer Announcements' started by John Penry-Evans, Mar 27, 2019.

  1. Apr 15, 2019 #41

    Factory-Fit

    Factory-Fit

    Factory-Fit

    Member

    Joined:
    Jan 2, 2012
    Messages:
    18
    Likes Received:
    11
    Location:
    North Newbald, York, United Kingdom
    Oil cooler radiator is fine at standard size, recommend unbolting it from the casing (vibration can crack the bracket) and mount it on fabric reinforced rubber strip hanging out to the side, the stock case has leak holes to blow fan air through the radiator but I blocked those to give max air to cool the heads and swung the cooler out to one side to catch airflow.
     
  2. Apr 15, 2019 #42

    wsimpso1

    wsimpso1

    wsimpso1

    Well-Known Member

    Joined:
    Oct 19, 2003
    Messages:
    5,365
    Likes Received:
    2,667
    Location:
    Saline Michigan
    OK, let's start with you, Factory-Fit. Are you a representative of ACE? Or just an apologist for them? Unless you are their representative, I did not ask you for anything, and maybe you should quit being offended by my question.

    I spent 37 years as an engineer, much of it in automotive powertrain design. I know about questions and having to answer them. That is why we usually have an operating envelope established early on and make sure that the product satisfies it. If you have a history of getting so many questions on your products that are difficult to answer, maybe:
    • You know too little about your product;
    • You are giving too little information about your product, or;
    • It looks like you have done an incomplete job in scheming out your product for market.

    Let's say you are looking to use this PSRU and you want to know if it will work on your airplane. You know the engine and its speed, you know the gear ratio and are exploring props with known MMOI, and you know your instantaneous pitch and yaw rates. You need to know if the PSRU will stand this duty, and have the temerity to ask the marketer of the drive that question. They did design it, they do have the details of the parts and can determine better than anyone else what the maximum gyroscopic moment and torsional conditions the drive will tolerate. And you get from them "No, I will not tell you if the bearings and shaft and housing will stand this - you will have reverse engineer my product and find out." And you expect that we will buy it anyway? And somehow determine that it is safe for the vehicle's lifetime. No, I expect that if you will not tell us if we can safely use it, we will not buy it.

    So buyer beware, huh? This is supposedly an engineered product. I asked a simple engineering question. Maybe it is not an engineered product. There are other drives out there where the builder complained that the airplane owner pulled g's. So maybe this drive is like that one, and should not be bought or used by anyone...

    Hmmm, just because there are many possible values within the operating envelope of the product does not mean that you can not rather easily know the edges of the envelope. I have done calculations of this sort many times... The fact that such calcs can be tedious does not relieve the builder of establishing the expected limitations of the device. And it is not like I am asking for rocket science here. Gyroscopic moments applied to the prop hub and inertia limits for resonance issues are not exactly space science. If you KNOW that the drive is designed to exceed some value, why not tell us that? Or maybe you are guessing...

    I made no mention of the build sources, but since you are so sensitive about India as a source, maybe we should be too. Not much risk of that. We still do not know if the designer even knows the limits of gyroscopic moments and propellor inertia limits that are OK with this drive.

    Billski
     
    pictsidhe and BoKu like this.
  3. Apr 16, 2019 #43

    Factory-Fit

    Factory-Fit

    Factory-Fit

    Member

    Joined:
    Jan 2, 2012
    Messages:
    18
    Likes Received:
    11
    Location:
    North Newbald, York, United Kingdom
    No commercial connection at all; John is a friend, I don't like bullying with inappropriate questions that cause him commercial damage; Indian manufacture was mentioned, ignoring that it was supervised by a Brit, which triggered my racism detector, would that be mentioned if it was German origin?

    Reason I structural queries vary, and there are many more than given below:-

    1) The Engineer inspecting is unfamiliar with the type
    2) The Engineer has too much information and hasn't sorted through it properly (happens often with 100+ pages)
    3) The Engineer has an agenda other than purely inspection and approval, such as proving to an audience how clever he is...

    You haven't addressed my statement on testing? An aerobatic aeroplane should be at least prop-hub tested; the variations run into millions of prop, turn rate, fatigue cycles and so on. So far the reduction structure has proved more robust than the casing it is bolted to on test, particularly with respect to the Briggs.

    I've not yet encountered an aerobatic aeroplane with an industrial engine and belt reduction drive, but would advise John at Ace to recommend 'on aircraft load testing' to verify suitability. Is that a serious query, or mere tugging a busy man's chain? Often queries are exposed as unrelated or miss that other elements in structure are weaker

    Very pleased you have done calculations of this sort many times. Why? Seems odd (and proven unsafe) to rely on calculations, when failure mode may be engine mountings, engine attachment points and so on, so 'whole system' requires load test for safety. I will continue to rely on load testing, particularly as Dr Gratton of Brunel University Aeronautics department used to demand it over calculations when he was examining my work. Ask him if you have further doubts.

    For a wider audience, recommend British Civil Airworthiness Requirements Section S Small Light Aeroplanes; its a free download and covers this subject in detail; if you have concerns about the strength of Ace Aviation's reduction drive bolt it to your engine, you will find a 16mm thick back plate plate in 6082(T6) alloy tends to be rather stronger than the castings it is attached to...
     
  4. Apr 16, 2019 #44

    wsimpso1

    wsimpso1

    wsimpso1

    Well-Known Member

    Joined:
    Oct 19, 2003
    Messages:
    5,365
    Likes Received:
    2,667
    Location:
    Saline Michigan
    We are adults here. If the builder wants to answer, he is an adult and can. If he chooses not to, he is an adult and can do so also. It is only the marketing of his business that is involved. In the spirit of full disclosure, I am not buying a drive in this size. I am asking the questions about gyroscopics and about MMOI because some PSRU builders are blissfully ignorant on these topics - the customers should know who is doing this right and who is guessing.

    This is HBA.com, we stay civil here and we assume the best not the worst as starting points in conversations. Bullying is inappropriate.

    I asked serious questions about the capability of the drive that are frequently ignored by some drive builders. There are PSRU's out there right now that were not designed to stand nominal flight loads including g's and pitch/yaw motion, and appear to have issues with same. I am inquiring of the known capability of this PSRU.

    In the case of my quieries on gyroscopic moment limits and prop MMOI limits, two lines in the spec sheet will solve the issue. The first requires a quick look at the total load picture on the bearings, prop shaft, and hub with gyroscopic moment added in. The second might require a TV survey of the range of engine firing characteristics, engine MMOI, and prop MMOI. If this seems over the top for effort, maybe a survey of successfully applied engine MMOI/prop MMOI combinations will yield an indication of combinations that can be expected to be successful.

    So far, we do not know which types of airplanes, which engines, which flywheels, and which props have worked well with the ACE drive, nor do we know how many are flying and with how many total hours have been flown. From your report one drive has been on a couple weight shift airplanes that got some hundreds of hours and survived a hard landing in the middle of those hours. That's nice. Powered chutes and weight shift trikes have very low pitch and yaw rates, and are conservatively flown. What if someone wants to use the ACE drive a little more aggressively, they might want to know that it is expected to be fine beyond their expected yaw and pitch rates...

    I did not bring up India sourcing of the drive or manufactured quality of the device. I have seen all kinds of good and bad products from four continents, and so far no one has a monopoly on either good or crappy. But if you are that sensitive about the manufacturing source and the age of the machine tools used, maybe we should be too...

    Not really sure about that first line... As I stated above, I have serious reasons to ask the questions based upon good engineering training and experience. The builder of the PSRU can provide confidence inspiring results of analysis or not. The market will then act upon, among other things, the confidence inspired.

    Not likely to either. Long successful career designing and sheparding into production powertrain pieces that are assembled into 100k to 1M transmissions per year and in production for more than a decade each. Suppliers say their "thing" is the right piece; we select one supplier from among the others; that supplier goes on to prove, first in analysis, then in testing, that their product is good; then we stuff them into our bigger product and find out if any issues remain. Yep, the supplier first has to supply evidence analytically and then with appropriate test data that it is good to our needs. If I or other hba.com members are to spend years building an airframe, are looking for a engine/PSRU/prop to give it motive power, we want to know that the system will work and run a long time without failures. Some of us will fly the airplane through the entire operating envelope, including hard pulls to near max g at Va, rapid stick and rudder doublets to clear the envelope for flutter, spins, and other events that may drive significant pitch/yaw rotation rates. Extensive life testing to see if the hub and internals of the drive will stay together is not part of it. Now maybe if ACE were marketing to a company who is intending to build hundreds, then some testing would be done by the airframe company, but they should contractually demand analytical and appropriate testing by the PSRU supplier first.

    No individual airplane builder will run 1000 hours on a stand with appropriate airflow at the highest temps we expect to see and inducing g's, pitch and yaw rates, etc somewhat exceeding our birds' capabilities. I put here that we should not waste our efforts on an engine/PSRU/prop unless the builder of the drive has some pretty good evidence that it will work well in our airplane. "here it is - good luck" makes me want to walk away and warn others to do the same.

    Nor I, but many airplanes can be spun, and some will be spun with throttle open. All three-axis airplanes can have the stick or rudder abruptly applied at Va producing significant pitch and yaw rates - this is a certification requirement that is generally mimicked in Experimentals. If ACE does some calcs on the shaft and bearing and hub designs, and then conservatively de-rates the thing and publishes a max gyroscopic moment, the customer can assess if their prop and their airframe will exceed that or not. It could be that the ACE drive is way robust, and saying it with a line on a spec sheet can be good for business. It could also be that the ACE drive should be restricted to some lower level of rotation rate, and knowing that can prevent forced landings and very bad publicity. Until it is checked in some way, none of us know.

    Likewise, a line or two (or a chart showing the know acceptable combinations) about the range of known acceptable MMOI combinations with the drive can also go a long way toward allowing customers to make good decisions as to suitability on their airplane and improve the marketability of the product.

    Not likely to urge any individuals or companies to do extensive testing of PSRU. As stated above, individuals will not make durability runs and companies will expect their suppliers to prove capability first.

    I have seen calcs run that I did not trust because I found errors in them - the boundary conditions are wrong, the assumptions are wrong, the cases chosen inappropriate, the wrong equations used, summation errors, etc. GIGO. On properly done analytical work, I have rarely been disappointed during a 37 year engineering career, 22 of them in transmission engineering. Did we run tests in the end? You bet, and that was to demonstrate we did the design right. We did occasionally do fine tuning or upgrades, but mostly we showed that we knew what we were doing in the first place.

    Look, if you want to be offended or feel a need to protect your friend, go ahead. The builders of PSRU are taking on a big responsibility - they own the link between engine power and the prop. This system has to be stone reliable or it should not be flown. If some primary design checks and serious testing have occured and the designer has confidence, it should be no big deal to include that in the spec sheets. If they have not been made and the customer is on his or her own, I say avoid that product until reliability has somehow been shown. I advise against customers doing the suppliers' proveout runs, but if you have a bunch of drives running and bunch of hours and MTBF over a couple thousand hours, well, even I will say they look pretty good.

    Billski
     
    BoKu likes this.
  5. Apr 16, 2019 #45

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    5,212
    Likes Received:
    1,282
    Location:
    North Carolina
    I will be using an Ace sized redrive. My first post in this thread was in the hope of getting some numbers to go on. I did not. I have tried asked questions civilly, and not gotten answers. Back to plan B, engineer my own drive. It's easier and cheaper than buying a ready made one then reverse engineering it to see what it is capable of. Factory fit, you are doing Ace no favours at all by telling potential customers they need to check his drive may be suitable after buying it. The reason some of us like to run numbers first, is to cut down on the wasted time and expense of broken parts that were never up to the job in the first place. Yes, I will be testing too, but I'd like to feel fairly sure it is strong enough, without being too heavy. This is aero engineering. Too little strength is bad, but so is too much...
     
    wsimpso1 and BoKu like this.
  6. Apr 16, 2019 #46

    BoKu

    BoKu

    BoKu

    Well-Known Member

    Joined:
    Aug 16, 2013
    Messages:
    2,123
    Likes Received:
    2,593
    Location:
    Douglas Flat, CA
    [snark redacted]

    Factory-fit, I second the earlier assessment that you are doing your friends no favors by attempting to defend their work in the absence of actual quantitative information. My recommendation, and I do mean this in the best possible way, is to quit while the hole you've dug is shallow enough to climb out of.
     
    wsimpso1, pictsidhe and BJC like this.
  7. Apr 16, 2019 #47

    cluttonfred

    cluttonfred

    cluttonfred

    Well-Known Member

    Joined:
    Feb 13, 2010
    Messages:
    6,287
    Likes Received:
    2,174
    Location:
    World traveler
    There's a whole lot more snark in this thread that needs to be redacted, Bob, though not from you. Congratulations, gents, you have managed to jump all over an established supplier and a satisfied customer, both of them longtime members though infrequent contributors (I wonder why?) to this group.

    Billski said, "This is HBA.com, we stay civil here and we assume the best not the worst as starting points in conversations. Bullying is inappropriate." Unfortunately, that's not how this thread has unfolded.

    Armilite's filling up the thread with comments and photos about other products seems to me wholly inappropriate. Truth be be told, Billski's comments are also so voluminous and technical that it doesn't come off like actually wanting a productive conversation, more like daring the supplier to provide any data at all so he can tear it apart.

    The whole thrust of this thread has not been welcoming, has not given the benefit of the doubt, and has been just plain not cool in my view.
     
  8. Apr 16, 2019 #48

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member

    Joined:
    Jan 24, 2011
    Messages:
    3,194
    Likes Received:
    1,376
    Location:
    US
    Tone aside, I think the actual information exchanged here has been very useful and valuable.
    1) Getting a firsthand report from Factory Fit on his experience flying with the Vanguard 627cc engine was very valuable. If someone wants to push this engine as he did (beyond the rated HP using higher RPMs and CR), they've at least got a glimpse of the potential pitfalls and the modifications that are common. And, for someone considering use of this very popular and available engine with the Ace redrive and a prop that is about the same, this is a lot better than starting from scratch. No, it's not a thousand hours, but it's more than I knew before. It didn't cost me a dime.
    2) ACE redrives: I've never seen this much technical information on these drives before. And, I think we may also have seen the extent (including the limits) to which the drive has been engineered. Those wanting to know if TV, resonance, or inertia limits have been deeply explored by ACE probably have their answer, which is better than not knowing (which is where I was before).
     
    Last edited: Apr 16, 2019
  9. Apr 16, 2019 #49

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    5,212
    Likes Received:
    1,282
    Location:
    North Carolina
    Perhaps factory fit could start his own thread about his trike adventures. I did suspect that the engine end case may be a bit too flimsy and that was useful.
    Meanwhile, I think we have ascertained that the Ace redrive seems to work ok for trikes, though we don't know what prop and flywheel MOIs are good. Anything more seems to be on your own R&D.
     
    Last edited: Apr 16, 2019
  10. Apr 16, 2019 #50

    Factory-Fit

    Factory-Fit

    Factory-Fit

    Member

    Joined:
    Jan 2, 2012
    Messages:
    18
    Likes Received:
    11
    Location:
    North Newbald, York, United Kingdom
    After the experience of rather more than a mere 'hard landing' (trike nose dug in marshy ground at 60mph and rolled into a ball, if Ace didn't fit full harness restraints this conversation would be ongoing) I hauled the pieces home and retrieved few usable items. The motor had lunched itself when the cast camshaft snapped and the GPS was located 50 feet away. The reduction drive was still bolted to a broken propeller, so was, and still is stronger than the sort of forces the propeller can exert. In short, if the redrive structure is capable of withstanding forces that break the propeller bolted to it, all the FAA-style bureaucracy-speak that could be aimed to cast doubt on it is irrelevant, as a propeller trying to break the redrive will find itself broken instead...

    That point ignored, dismissed and obscured, triggered my concern about inappropriate queries; the redrive was unbolted, cleaned of mud and the bearings checked. It was attached to a new Briggs 627 and after another 20-30 hours flight demonstrated to a team from Southampton University for an unmanned drone charity project to drop medical supplies in warzone areas. After observing the tests for static thrust, they accepted and drove away with the engine and reduction drive.

    The next project is a fuel injected 800cc ATV engine; this is water cooled, four valve and chain driven OHC; so far the new Ace Aviation reduction is doing just fine, although I've changed the multi V belt to 19 rows to cope with 61 horsepower, and redone the tension calculations. Ace are happy to make different ratios and that cooperative approach may catch them off guard occasionally. As belt wrap on the small pulley reduced with a bigger secondary (the formula for tension is related to the sine of the belt wrap angle) tension has had to increase, I don't want to add an idler as that increases belt flex frequency.

    So making a redrive with reserves of strength paid off; it's appropriate for use in homebuilt aircraft, agriculturally simple, and strong enough to withstand a nose-over; I'm really happy with the finish on all mine and the machinery used to make it measures out an accurate end product. Why someone wants to kill off a useful experimental accessory with a welcome flexible approach to making 'specials' baffles me, I thought us Brits were bad at head games...;-)
     
  11. Apr 16, 2019 #51

    BBerson

    BBerson

    BBerson

    Well-Known Member

    Joined:
    Dec 16, 2007
    Messages:
    10,806
    Likes Received:
    1,923
    Location:
    Port Townsend WA
    Seems to me some photos of what has worked is sufficient for these custom one offs. This isn't automotive numbers. It would be impossible to design for each individual's installation. An industrial powered single seater is rare, and need not meet the engineering level of a two or four seater as long as that sole pilot understands there is risk with any conversion. Every flight is a test flight and could fail anytime.
    I think anyone that needs specific MMOI information should be capable of figuring that out for themselves from the drawings.
    Most won't bother.
     
  12. Apr 16, 2019 #52

    Factory-Fit

    Factory-Fit

    Factory-Fit

    Member

    Joined:
    Jan 2, 2012
    Messages:
    18
    Likes Received:
    11
    Location:
    North Newbald, York, United Kingdom
    Thanks

    Ultimate test of the reduction drive was rather more than surviving a mere 'hard landing'; trike was rolled into a ball when the nose dug into marsh ground at 60mph, flare wasn't an option due to power lines. If Ace hadn't fitted a full harness belt setup I wouldn't be typing this today, Propeller was very broken and little re-usable parts remained of the airframe, GPS was found 50 feet away and the Briggs lunched itself when the cast iron cam broke.

    After retrieval of the wreck the Reduction Drive was cleaned of mud, checked and fitted into a new Briggs motor with reinforced cam, flown for another 20-30 hours, then handed to a team at Southampton University for a charity project, for an unmanned drone to drop medical supplies in war zones. They inspected, watched demonstration of static thrust and drove away with it after a thorough examination, the University Engineering Department were supplied with the design CAD drawings and apart from a couple of calls for information when mounting it on a dyno testbed, are happy.

    Hence impatience with FAA bureaucrat style attacks on the product; if the redrive can shrug off sufficiently high forces applied to break the installed propeller, demanding checks on what forces it is possible to impose via the propeller, is by any logic, inappropriate... Not the first time queries on submissions have required logic rather than maths.

    Current project is a 61hp ATV unit, an 80° V-Twin with four valve heads, chain OHC and fuel injection. Only change to the Ace Redrive bought for this, was 220 diameter main pulley with 100 diameter crank; this reduced belt wrap on the small pulley and necessitated working again through the belt tension calculations, which related to the sine of belt wrap angle and can be applied to other combinations.

    What we lose by attacking Ace Aviation is a useful resource; one happy to make 'specials' and flexible when different ratios or mounting plates are requested, the redrive on my ATV unit is little different from the base design apart from 19 rows on the belt to cope with 61hp, increased tension and tweaks to mounting bracketry from engine to redrive backplate.

    I can't unsubscribe from this group so sadly obliged to block notifications, it's approaching the flying season, and need time on this engine; so far, so good at 7.5 litres burned in one hour plus two five minute warm up times each end. EFI means instant starting and auto compensation for height, and the Briggs used to ice up and needed carb heat, this doesn't..
     
  13. Apr 16, 2019 #53

    wsimpso1

    wsimpso1

    wsimpso1

    Well-Known Member

    Joined:
    Oct 19, 2003
    Messages:
    5,365
    Likes Received:
    2,667
    Location:
    Saline Michigan
    Kill it off? I just want enough info so we can know to properly use the things.

    ACE is not the first supplier I have asked these questions of. I would love to see John list the maximum moment and cite that as above what can be achieved with known props and spin rotation speeds. I would love to see John plot the engine and prop MMOI of flying customers so we can know not to run flywheels or props outside of known good levels. It would be terrific if the fleet size, fleet hours, and a total lack of failures were published. Without this sort of info, we have to pay our money and trust...

    Billski
     
    BoKu likes this.
  14. Apr 16, 2019 #54

    BoKu

    BoKu

    BoKu

    Well-Known Member

    Joined:
    Aug 16, 2013
    Messages:
    2,123
    Likes Received:
    2,593
    Location:
    Douglas Flat, CA
    This is a logical fallacy sometimes known as "shooting the messenger." Billski asked a couple of relatively simple and straightforward questions, and your response was essentially "why are you attacking me?"

    Actual pro tip from someone who's been selling into the amateur-built aircraft marketplace for the last twenty years: When someone asks a question about your life-critical product, consider responding with a mix and match of the following possible responses. Use clear, simple language and a minimum of obfuscation:

    "I don't know."

    "Good question. I can check on that and get back to you on that."

    "I don't know, it's never come up before."

    "Our testing so far demonstrates that it is probably high enough for all practical purposes."

    "We designed it to thus and such a value, but we haven't had the opportunity to test it."

    "I don't understand the question, can you please re-phrase it?"

    "It depends on a wide variety of factors, but under x conditions the answer is y."

    --Bob K.
     
    pictsidhe and wsimpso1 like this.
  15. Apr 16, 2019 #55

    wsimpso1

    wsimpso1

    wsimpso1

    Well-Known Member

    Joined:
    Oct 19, 2003
    Messages:
    5,365
    Likes Received:
    2,667
    Location:
    Saline Michigan
    Bill,

    I am not asking anyone to design for particulars. I am asking for limits on MMOI times prop rpm times rotation rpm and some guidance on acceptable prop and flywheel MMOI so the airframe builder can check it out before selecting a box. It will help to know "this might be heavier but that box will not last if I do spins..." or that "no one has run a prop with this inertia yet ..."

    Billski
     
  16. Apr 16, 2019 #56

    BBerson

    BBerson

    BBerson

    Well-Known Member

    Joined:
    Dec 16, 2007
    Messages:
    10,806
    Likes Received:
    1,923
    Location:
    Port Townsend WA
    I haven't found this information in Type Certificate Data Sheets, Overhaul Manuals or installation manuals from Lyc or Continental. Or any PSRU manufacturer.
     
  17. Apr 17, 2019 #57

    poormansairforce

    poormansairforce

    poormansairforce

    Well-Known Member

    Joined:
    Mar 28, 2017
    Messages:
    306
    Likes Received:
    61
    Location:
    Just an Ohioan
  18. Apr 17, 2019 #58

    samyguy

    samyguy

    samyguy

    Well-Known Member

    Joined:
    Sep 20, 2011
    Messages:
    84
    Likes Received:
    12
    Location:
    Lincoln Nebr
    Did Valley Engineering provide this information??
     
  19. Apr 17, 2019 #59

    samyguy

    samyguy

    samyguy

    Well-Known Member

    Joined:
    Sep 20, 2011
    Messages:
    84
    Likes Received:
    12
    Location:
    Lincoln Nebr
    J-Bird engines? For their redrive
     
  20. Apr 17, 2019 #60

    BBerson

    BBerson

    BBerson

    Well-Known Member

    Joined:
    Dec 16, 2007
    Messages:
    10,806
    Likes Received:
    1,923
    Location:
    Port Townsend WA
    I am aware of the Rotax Service letter, which apparantly addresses a wear rate or warranty issue.
    My original Rotax manual has no mention.
    It would be nice if users such as Kevin would post info for in service problems, but apparently has been driven from this forum.
     
    Last edited: Apr 17, 2019

Share This Page

arrow_white