Engines: Cost and weight per HP

Discussion in 'Firewall Forward / Props / Fuel system' started by Vigilant1, Jul 29, 2018.

Help Support HomeBuiltAirplanes Forum by donating:

  1. Jul 31, 2018 #61

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member

    Joined:
    Jan 24, 2011
    Messages:
    3,743
    Likes Received:
    1,653
    Location:
    US
    Yes, it could use some sprucing up. I get the impression he stays pretty busy just based on his reputation, which is a good thing.

    Here's a picture from the website of a Onex builder who bought a Hummel/Casler 2400cc engine. I see a magneto going to the top plugs. The bottom plugs look like they are fired by an ignition system triggered by a unit in the distributor hole--maybe this one from Great Plains ($470, incl plugs). If so, the engine could be hand-propped using the magneto, then turn the secondary ignition on >after< the engine is running.

    I can't tell much about the heads Scott is using from the photo. There's a lot of other stuff to like about the engine, though. (The oil cooler on top is just the way it is typically set up on the Onex, it could go anywhere).


    [​IMG]
     
    Last edited: Aug 1, 2018
  2. Jul 31, 2018 #62

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    6,429
    Likes Received:
    1,670
    Location:
    North Carolina
    Unless they've changed the design significantly from older versions, the balancer will be a nightmare if you turn this engine horizontal. Be wary of vertical Briggs singles! Out of the box weight is the same as the 627cc vanguard twin, though they cost far more.
     
  3. Jul 31, 2018 #63

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    11,663
    Likes Received:
    2,188
    Location:
    Port Townsend WA
    The sliding balance weight needs some guides to hold it if converted. Or just remove the balance weight and deduct 6 pounds.
     
  4. Jul 31, 2018 #64

    Hot Wings

    Hot Wings

    Hot Wings

    Well-Known Member HBA Supporter

    Joined:
    Nov 14, 2009
    Messages:
    6,208
    Likes Received:
    2,178
    Location:
    Rocky Mountains
    D......................c....................p...................................d
    ......e.........u.............t......................o...............n....................s
    ...........d..........................6......................u

    :gig:
     
    Topaz likes this.
  5. Aug 1, 2018 #65

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    11,663
    Likes Received:
    2,188
    Location:
    Port Townsend WA
    The crank is counterweighted. Removing the reciprocating anti vibration weight might not matter much at all on a prop plane. At full power the single cylinders pulses shake the engine from intermittent torque. Can't be eliminated.
     
  6. Aug 1, 2018 #66

    gtae07

    gtae07

    gtae07

    Well-Known Member

    Joined:
    Dec 13, 2012
    Messages:
    1,773
    Likes Received:
    1,049
    Location:
    Georgia
    I believe that is the factory-new certified engine cost. And that's list price. Few things ever sell at list price.
     
  7. Aug 1, 2018 #67

    Topaz

    Topaz

    Topaz

    Super Moderator

    Joined:
    Jul 30, 2005
    Messages:
    13,573
    Likes Received:
    5,234
    Location:
    Orange County, California
    All Scott's listed weights include everything needed for the engine to run except oil. Weight of the prop and hub are additional, of course. I wrote him one time and asked him this exact question.

    Actual general arrangement drawings, specs, and a power curve seem to be exponentially harder to get with the inverse of the engine price. Heaven forbid that you ask for reasonably accurate fuel-consumption or even >gasp< SFC. It's as if the manufacturers don't care that someone has to design a firewall-forward installation for their products, and the distributors follow suit. I've asked a few small-engine manufacturers - some of them specifically aircraft engines - for basic data like this and the e-mail response is usually the textual equivalent of looking at me as if I had a third eyeball in the middle of my forehead.
     
  8. Aug 1, 2018 #68

    TFF

    TFF

    TFF

    Well-Known Member

    Joined:
    Apr 28, 2010
    Messages:
    11,432
    Likes Received:
    3,171
    Location:
    Memphis, TN
    I can see why fuel burn is not quoted. How its propped and the airframe it's on will make too much a difference. There is no standard to test to.
     
  9. Aug 1, 2018 #69

    Pops

    Pops

    Pops

    Well-Known Member

    Joined:
    Jan 1, 2013
    Messages:
    6,925
    Likes Received:
    5,840
    Location:
    USA.
    Good with the mag it can be hand propped. The mag is the new surplus mag, nothing wrong with that. I do not like the oil cooler in that location. Its not a full flow cooler. I think you can get more air through the cooler mounted on the lower firewall in the low pressure area and large scat from the baffling. That is the easiest way. I welded aluminum bosses on to the same cooler that was drilled and tapped for oil lines. Ran the oil from the front oil pump cover for full flow and then back to the block. Just a bypass plate on top of the engine where the oil cooler is mounted.
     
  10. Aug 1, 2018 #70

    Marc W

    Marc W

    Marc W

    Well-Known Member

    Joined:
    Apr 1, 2017
    Messages:
    279
    Likes Received:
    181
    Location:
    Colorado
    I have a 2180 built by Scott. It has the electronic ignition and surplus magneto like the picture. I believe the electronic ignition is the one sold by Great Plains. The mag only has 15 degrees of lag. People have modified the mags to increase the lag so you can hand prop. 25 degrees of lag is better to hand prop. I bought one of the surplus mags on ebay to experiment with.

    My oil cooler is mounted on the bottom of the engine. An inlet feeds air to the bottom of the crankcase and the air exits through the oil cooler.

    Oil Cooler.jpg

    Scott is busy! I called him a month ago about going through my engine since it has been sitting for 4 years. He was backlogged 5 months.
     
    Vigilant1 and Pops like this.
  11. Aug 1, 2018 #71

    Pops

    Pops

    Pops

    Well-Known Member

    Joined:
    Jan 1, 2013
    Messages:
    6,925
    Likes Received:
    5,840
    Location:
    USA.
    The Slick mag made for the VW has 25 degrees of lag but the cost is like gold.
    I see you are using the full oil flow cooling system, great. No oil control piston to stick and take the oil cooler out of the system.
     
  12. Aug 1, 2018 #72

    Topaz

    Topaz

    Topaz

    Super Moderator

    Joined:
    Jul 30, 2005
    Messages:
    13,573
    Likes Received:
    5,234
    Location:
    Orange County, California
    Neither SFC, nor fuel consumption at a given power setting, are influenced by the prop, the airframe, or anything else beyond the engine itself. Those things influence power setting for a given performance. SFC is a measure of power output per unit fuel and unit time.

    SFC is the standard measurement of fuel consumption by a gasoline engine from an engineering perspective, precisely because it's not influenced by the airframe.
     
    mcrae0104 likes this.
  13. Aug 1, 2018 #73

    blane.c

    blane.c

    blane.c

    Well-Known Member HBA Supporter

    Joined:
    Jun 27, 2015
    Messages:
    3,050
    Likes Received:
    534
    Location:
    capital district NY
    Couldn't a vibrator/exciter be put on one or the other ignition systems to facilitate easier starting and make hand propping feasible? And would it be less or more expensive than a Slick mag?
     
  14. Aug 1, 2018 #74

    TFF

    TFF

    TFF

    Well-Known Member

    Joined:
    Apr 28, 2010
    Messages:
    11,432
    Likes Received:
    3,171
    Location:
    Memphis, TN
    It is and isn't. Without a standard it isn't. An airplane standard. Personally I think people put too much into the HP numbers beimg precise, especially with a low volume product. The problem is with application. Climb prop never develops load on the engine to get to max horsepower and a cruise prop never lets the rpm get to the max HP point. Of course as altitude changes the producible horsepower is changing. True fuel consumption is going to be about application. Add to extremes of clean or draggy airframes and you will probably get 20% true number swings for the same engine.
     
  15. Aug 1, 2018 #75

    mcrae0104

    mcrae0104

    mcrae0104

    Armchair Mafia Conspirator HBA Supporter

    Joined:
    Oct 27, 2009
    Messages:
    2,938
    Likes Received:
    1,941
    Location:
    BDU, BJC
    BSFC is variable, depending on torque produced and RPM. Selecting a cruise prop vs climb prop would be akin to the 2nd/4th/5th gear points on this chart. I don't think aircraft engine manufacturers produce these charts for public consumption, but it would be helpful in selecting a prop for the intended design point if efficiency is the goal.

    A clean or draggy airframe shouldn't change the BSFC (and I'm not even sure how much % difference the prop will make). I presume that higher altitude would simply limit power output without changing the BSFC chart, but the chart probably assumes a particular mixture (stoich? best power? I don't know...).

    image.jpg
     
    blane.c likes this.
  16. Aug 1, 2018 #76

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    11,663
    Likes Received:
    2,188
    Location:
    Port Townsend WA
    The Lycoming operators manual has charts.
     
  17. Aug 2, 2018 #77

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member

    Joined:
    Jan 24, 2011
    Messages:
    3,743
    Likes Received:
    1,653
    Location:
    US
    Is the 21HP version still available? This retailer says that they have been discontinued, and that the B&S 540cc vertical engine that is currently in production provides 19HP (gross). It sounds like they either changed the compression ratio or they got caught, er, decided to relabel the same product for a lower HP.

    Hmm--a single-cylnder 19 HP engine that weighs 50 lbs, but may have a bit of a shake if the balancer were removed. If we could Siamese two of them together, we'd be at about 100 lbs, 38 HP, maybe a lot of the shake gone, at a price of about $1000. That would be something, but I'm sure a lot harder to do than to think about.
     
  18. Aug 2, 2018 #78

    BBerson

    BBerson

    BBerson

    Well-Known Member HBA Supporter

    Joined:
    Dec 16, 2007
    Messages:
    11,663
    Likes Received:
    2,188
    Location:
    Port Townsend WA
  19. Aug 2, 2018 #79

    Vigilant1

    Vigilant1

    Vigilant1

    Well-Known Member

    Joined:
    Jan 24, 2011
    Messages:
    3,743
    Likes Received:
    1,653
    Location:
    US
    Marc, is that the installation on your Thatcher CX4? My Sonex is setup the same way (I think most Sonexes are like this, though those who have fitted the turbo had to move the cooler to the top of the engine, as it is done on the Onex). It works well, and keeps the air duct and oil lines short. It does make changing the oil a bit of a bother since the oil cooler has to be moved to remove the cover and screen installed on the bottom of the oil pan.
     
  20. Aug 2, 2018 #80

    pictsidhe

    pictsidhe

    pictsidhe

    Well-Known Member

    Joined:
    Jul 15, 2014
    Messages:
    6,429
    Likes Received:
    1,670
    Location:
    North Carolina
    Briggs got into legal trouble over their claimed hp a few years ago. Most of the smaller engines are now rated in torque. That way they didn't have to obviously derate them.
     

Share This Page

arrow_white