B&S 49-series (810cm3/49ci) for aircraft use - TiPi's Q&A thread

Discussion in 'Firewall Forward / Props / Fuel system' started by TiPi, Oct 4, 2019.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Oct 13, 2019 #21

    karmarepair

    karmarepair

    karmarepair

    Well-Known Member

    Joined:
    Jan 13, 2011
    Messages:
    63
    Likes Received:
    19
    Location:
    United States
    I have query in to Universal Hovercraft about the OEM for the Taperlock bushings. These couplings are pretty generic in the US, although "Taper-Lock" is a Gates trademark; here is a data sheet on one manufacturer's "P1" size coupling with an 1-1/8" finished bore that looks like what Universal has on offer https://www.bbman.com/catalog/product/P1x1-1_8
    Torque Capacity (lb/in) 192
     
  2. Oct 13, 2019 #22

    TiPi

    TiPi

    TiPi

    Well-Known Member

    Joined:
    Aug 25, 2019
    Messages:
    148
    Likes Received:
    149
    Location:
    Mackay (AUS)
    not sure if these specs are correct, torque is only 22Nm (1/3 of the actual engine torque), material is steel and Al usually has lower values due the the lower tension/compression values.
    The "Taper Lock" name is the system of bushes with matching pulleys, gears etc, not the style that Hovercraft calls taper lock. The 1610 bush is very marginal for torque transmission, slip torque on a 28mm shaft is only about 170Nm with no key. With key, the value is higher but Fenner refers to their tech department as the slip will then be at the taper interface.
    upload_2019-10-13_16-20-49.png
     
  3. Oct 13, 2019 #23

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    6,980
    Likes Received:
    1,926
    Location:
    North Carolina
    Taper-Lock was originally a Dodge manufacturing trademark, now with Baldor Electric. Gates uses it with permission.
    I looked at using higher clamping force with the taper locks, but it's marginal. Torque capacity needs to be much higher than output torque if the prop is now the flywheel. One book that I have suggests a figure of 7x. The key has very limited torque capacity, They are usually a fairly soft iron, so not highly abuseable.
     
  4. Oct 13, 2019 #24

    karmarepair

    karmarepair

    karmarepair

    Well-Known Member

    Joined:
    Jan 13, 2011
    Messages:
    63
    Likes Received:
    19
    Location:
    United States
    They taught me at engineering school never to rely on the key.

    The P1 size taperlocks sold by Universal SEEM inadequate, UNLESS that spec is wrong, and those values are ft-lbs? Even the larger B&B Q and R sizes only go up to about 350 ft-in = 29 N-M. BUT I've seen these values described as "Wrench Torque", which to me indicates the installation torque on the cap screws, and NOT the carrying capacity of the coupling. Hmmmm.....

    Still looking for better data...the slightly different QD taper bushings have torque capacities from 3500 inch-lbs for the smallest available in stock for an 1-1/8"/28mm shaft ("SH"), all the way up to 30,000 in-lbs for the largest for that shaft size ("F") http://www.regalpts.com/ImagesPower...owning-Q-D-Bushings/Browning Q-D Bushings.png
    400 N-M = 3540.3 so a style QD, size "SD" or "SDS" should work, and the "grip length" (E on the data sheet) is .88" to 1.38". Back converting to the P1 split taper bushing, it has a grip length of 1-5/8 inches (1.625"=41.275mm). I'm beginning to believe they might work....interpolating in the QD tables, their capacity MAY be as high as 12,000 in-lbs = 1355.82 N-M. I've made inquiries to Regal for better engineering data.

    The Tsubaki web site is NICE. I particularly like their AD-N bushes. https://tt-net.tsubakimoto.co.jp/tecs/pdct/kpl/pdct_Dtl_PL-ADN.asp?kata=PL028X055AD-N LOTS of length, and TWO tapers. MORE than enough capacity. Fits in a straight bore. I've made inquiries to a US distributor about price. I could not get the Fenner site to work at all.

    And as near as I can see, the Universal bits use a STEEL bushing in an Aluminum hub. I'd love to be able to use them, as they are cheap and readily available.

    I like what you're doing with the B&S 49 series, but I'm actually thinking more about a Kohler Command Pro 752 or 940 horizontal shaft conversion, with MINIMAL modification - heads up, direct drive. Universal hub off the PTO end, lighten the flywheel up.
     
  5. Oct 15, 2019 #25

    karmarepair

    karmarepair

    karmarepair

    Well-Known Member

    Joined:
    Jan 13, 2011
    Messages:
    63
    Likes Received:
    19
    Location:
    United States
    Still on the Universal Hovercraft bits...the type of bushing they use is called a Browning Split Taper Bushing. Browning was a major OEM of drive components, and now is part of Regal-Beloit - which you would think would be in Wisconsin. Nope. The Philippines. Some back and forth:

    Ryan Young
    Sub: Torque capacity of q2 split taper bushing on 1-1/8 inch shaft
    To: ApplicationEngineering.PTSolutions@regalbeloit.com

    Your specifications list “wrench torque” but not actual capacity.
    Could I get the same data for the P1, P2, Q1, same bore diameter?

    Hi,
    Information is proprietary.
    Please advise your required Torque and I can advise if the bushing can accommodate it.
    Thanks,

    400 N-M. What is the smallest coupling that can handle that level of torque on a 1-1/8” shaft?
    I’d LIKE to use the P1, if it can handle that level of torque.

    P1, P2 and Q1 can handle the 400N-m (3540 in-lbs) torque capacity.

    Regards,

    Thanks,

    ROMYSAN IRIS DELA CRUZ
    I find this oddly unsatisfying, although I'm not completely sure why. Why is this WORSE than the numbers listed in the Tsubaki web page? I guess since I can't see the TRENDS. How MUCH more than the asked for torque will the P1 reliably transmit?


     
    Vigilant1 likes this.
  6. Oct 15, 2019 #26

    TiPi

    TiPi

    TiPi

    Well-Known Member

    Joined:
    Aug 25, 2019
    Messages:
    148
    Likes Received:
    149
    Location:
    Mackay (AUS)
    Thanks for that. I'm always a bit hesitant with companies that are not publishing their engineering data.
    I have a Tsubaki AD-N lock already, unfortunatley they only come in metric (28mm) so I will have to machine the PTO end of the crank if I use this one. Still going back and forth on the alternator (flywheel or PTO end) that will dictate the final design of the prop hub and shaft interface. The transmissible torque is 755Nm, so well above what I need.
     
  7. Oct 16, 2019 #27

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member Lifetime Supporter

    Joined:
    Jan 24, 2011
    Messages:
    4,160
    Likes Received:
    1,884
    Location:
    US
    FWIW: US parts house McMaster-Carr carries a wide variety of taperlocks in SAE/Imperial sizes. There are dimensions, drawings, and prices are at the link, but no ultimate torque values. It is possible the ultimate source for these is the same company karmarepair is talking to in the Philippines.

    I'm guessing you've rejected the idea of using shrink fit prop hub? Nobody likes the "excitement" of assembling them, nor the "hope you like it, because getting it off will be a dicey proposition" aspect. But, it is a single piece, light, and typical users would have little need to remove them during the life of the engine. I haven't done the math regarding the B&S shaft and potential hub torsional capacities, as you may have already rejected the idea for other reasons (but did find a nice calculator). Shrink fit prop hubs have given good service on VW aero engines (2 cyl and 4) of stock stroke, but not the larger engines (in fairness, IIRC, the shrink fit hubs stayed firmly attached even with the larger engines, the problem was the crank.). Obviously, the torque pattern of the B&S V-twins and the crank stub dimensions will different from the VW.
    VW Shrink fit hub listing at Great Plains Aircraft Supply (bottom of page)

    Shrink Fit hub installation instructions
     
    Last edited: Oct 16, 2019
  8. Oct 16, 2019 #28

    TiPi

    TiPi

    TiPi

    Well-Known Member

    Joined:
    Aug 25, 2019
    Messages:
    148
    Likes Received:
    149
    Location:
    Mackay (AUS)
    It has crassed my ming for a few seconds. Cons are:
    Precision of machining required (shaft and hub)
    Unlike a VW, the Briggs can't be disasembled with the prop hub on the PTO shaft

    As this is still an experimental engine, I expect an internal inspection, modification or repair to occur a few times in it's early life. The shrink-fit hub would make this too difficult as it can't be fitted until the engine is assembled and needs to be removed prior to disassembly.
     
  9. Oct 16, 2019 #29

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    12,201
    Likes Received:
    2,401
    Location:
    Port Townsend WA
    Maybe a tapered adapter could be fitted with a shrink fit on the 1/1/8" shaft. The hub would have a matching taper and the hub could be removed and the tapered adapter would remain.
     
  10. Oct 17, 2019 #30

    TiPi

    TiPi

    TiPi

    Well-Known Member

    Joined:
    Aug 25, 2019
    Messages:
    148
    Likes Received:
    149
    Location:
    Mackay (AUS)
    Good thinking! A permanently installed taper that is a tad smaller than the bearing dia (41.36mm / 1.625"). Have to think about that design
     
  11. Oct 17, 2019 #31

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member Lifetime Supporter

    Joined:
    Jan 24, 2011
    Messages:
    4,160
    Likes Received:
    1,884
    Location:
    US
    And make that shrink-fit tapered adapter have outside dimensions the same as one of the standard prop hubs? Or even a prob hub for a VW engine.

    Or, yes, make it narrow enough to squeeze through the bearing hole for disassembly.

    Getting back to taperlocks:
    This vendor ("Arrowprop") claims to manufacture grip-lock propeller hubs (shafts up to 1 7/8"). Less than $110 (US), and maybe it is all one piece, which would be nice--fit it on the shaft, mount the prop directly to it.
    They also sell propellers for small engines, and it appears they'll carve whatever you want.
    I have no connection with them.
     
    Last edited: Oct 17, 2019
  12. Oct 17, 2019 #32

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    12,201
    Likes Received:
    2,401
    Location:
    Port Townsend WA
    I would make my own if I needed it. So it depends on what you want.
    The small 1.125" shaft concerns me.
    For a proper big shaft, the crank could be removed and the PTO journal could be turned down 1/8" smaller and a much larger PTO shaft could be fitted over it. (1.5" or whatever outside diameter machined to fit the existing case bearing)
     
  13. Oct 17, 2019 #33

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    6,980
    Likes Received:
    1,926
    Location:
    North Carolina
    So, like a tapered crank, but built up with a nice weak spot between the adaptor and crank journal?
     
  14. Oct 17, 2019 #34

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    12,201
    Likes Received:
    2,401
    Location:
    Port Townsend WA
    Yes, the solution to that is post #32. Especially if you want an extended prop hub.
     
  15. Oct 17, 2019 #35

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member Lifetime Supporter

    Joined:
    Jan 24, 2011
    Messages:
    4,160
    Likes Received:
    1,884
    Location:
    US
    Well, we're just one step away from boring out the case a bit and installing a bigger bearing for a custom prop hub to ride in. Like a Force One hub used in VW engine, but for a B&S engine. And, you could build in a thrust bearing while you're at it, I suppose. From Great Plains Aircraft Supply:
    Product listing and photos: http://www.greatplainsas.com/scphub.html
    Installation Instructions: http://www.greatplainsas.com/if1ph.html

    This rabbit hole is getting pretty deep.
    For consideration:
    1) The cranks are not breaking in SE-33s driving props on the flywheel end. How much difference is there with the shaft on the PTO end?
    2) Does buying the crank with the tapered-shaft PTO end make life significantly better (by avoiding the step-down/shoulder to the 1 1/8" PTO shaft diameter)? Of course, there still needs to be a prop hub found/made to fit that tapered crank nose.
     
    Last edited: Oct 17, 2019
  16. Oct 17, 2019 #36

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    6,980
    Likes Received:
    1,926
    Location:
    North Carolina
    I want to use a tapered crank. Way less hassle and much stronger than trying to add a taper on. Don't forget, if you grind the journal down to sleeve it, you will now have a weak point somewhere else. If I wanted a long prop hub, I'd have a long prop hub. A lengthened crank won't help unless you make a new end cover to suit. That would also be needed for bigger bearings.

    I've been looking at using the 1 1 /8 PTO, the numbers for a redrive don't make me feel warm and fuzzy. Direct drive would be higher stress.

    The 1 1/8 keyed shaft is much weaker than the flywheel taper end. What works on the flywheel end, could easily break a 1 1/8 PTO.

    Flywheel end drive has been shown to work. A PTO drive would be higher stressed whatver you did with a 1 1/8 PTO. A tapered crank would be stronger than a flywheel drive. Since we are delving into these engines for simplicity and low cost, eleborate engineering to 'taperise' a straight crank with a weak spot somewhere seems a bit silly to me when you can just buy a crank or engine with a suitable tapered PTO.
     
    blane.c likes this.
  17. Oct 17, 2019 #37

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    12,201
    Likes Received:
    2,401
    Location:
    Port Townsend WA
    I intend to use the flywheel taper end. My suggestions was only for TiPi and others that want to use the stock 1 1/8" PTO for whatever reason.
     
  18. Oct 17, 2019 #38

    Hot Wings

    Hot Wings

    Hot Wings

    Well-Known Member HBA Supporter

    Joined:
    Nov 14, 2009
    Messages:
    6,448
    Likes Received:
    2,360
    Location:
    Rocky Mountains
    Almost inarguable the "best" solution..........but unless it is needed* it goes beyond the idea of cheap. If we were making a few thousand a year it is a great idea.

    *
    https://www.homebuiltairplanes.com/...anguard-conversions.31620/page-18#post-475748
     
  19. Oct 18, 2019 #39

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    6,980
    Likes Received:
    1,926
    Location:
    North Carolina
    The standard case isn't thick enough to take a bigger bearing. So, add a new end cover.
    I'm going to work with the available major parts. As long as I don't go too crazy with power, they should be fine.

    If you are going to make a few thousand a year, a completely new engine seems like the best idea...
     
  20. Oct 18, 2019 #40

    TiPi

    TiPi

    TiPi

    Well-Known Member

    Joined:
    Aug 25, 2019
    Messages:
    148
    Likes Received:
    149
    Location:
    Mackay (AUS)
    The whole idea of using a mass-produced industrial engine is to keep a small aircraft with modest power needs affordable. So my goal for the conversion is to minimise all machining work (external), use proven components where suitable (prop hub) and only modify what clearly needs upgrading (weight reduction, oil supply, maximising power at 3,600rpm). If you have $10k to spend, buy a HKS, Verner, 1/2 Rotax or some other custom-built unit. A well thought-out conversion of a 49-series engine producing 35hp at 3,600rpm should be possible under USD2,500 complete.
     
    Vigilant1 and Matt D Murdoch like this.

Share This Page



arrow_white