+ Reply to Thread
Page 1 of 5 12345 LastLast
Results 1 to 15 of 63
Like Tree15Likes

Thread: Power of UL POWER AERO ENGINES ?

  1. #1
    MYR
    MYR is offline
    Registered User
    Join Date
    Sep 2012
    Location
    France
    Posts
    8

    Question Power of UL POWER AERO ENGINES ?

    Hi all,
    My UL POWER 260i engine doesn't start up yet.
    I have heard some problems about the veritable power of these engines.
    It seems to me that the power of the 100hp engine is 89hp, and the power of the 97h engine is 79 hp.
    Are there here any persons that believe that the power of the UL POWER engines are over estimated ?
    Thanks.
    Sorry for the mistakes I can do. I am not an english speaker person.
    Forum about UL POWER (in french) : http://www.forum-ulm-ela-lsa.net/viewforum.php?f=443

  2. #2
    Registered User
    Join Date
    Mar 2008
    Location
    Leuven Belgium
    Posts
    409

    Re: Power of UL POWER AERO ENGINES ?

    Tho power claimed by UL-Power looks OK to me. Their torque and power figures are as we should expect from a reliable engine.
    Still, remember always...the real power of any engine is only known after a run on a power test-bench - so if you have doubts
    about your engine try to find out his real power output.

    Different methods exist to do this.

  3. #3
    Registered User rv6ejguy's Avatar
    Join Date
    Jun 2012
    Location
    Calgary, Alberta, Canada
    Posts
    1,153

    Re: Power of UL POWER AERO ENGINES ?

    Like some other small, direct drive engines, the manufacturers often rate them at higher rpms to make them look better. UL rates some engines at either 3000 or 3300 rpm but if your propeller is only rated for 2700-2800 rpm, the hp will be substantially lower. They do show the ratings at some lower rpms in their charts I believe. If you can turn the full rated rpm, I would tend to think their hp is fairly accurate but as said above, only a dyno test would confirm that.

  4. #4
    Registered User clanon's Avatar
    Join Date
    Jun 2007
    Posts
    532

    Re: Power of UL POWER AERO ENGINES ?

    This number will be more important (at least for choosing the prop and pitch) than HP...since this is direct drive:
    218 Nm [160.8 ft.lbf] @ 2700 rpm
    "Do what you can, with what you have, where you are"

    (Theodore Roosevelt)

  5. #5
    Registered User rv6ejguy's Avatar
    Join Date
    Jun 2012
    Location
    Calgary, Alberta, Canada
    Posts
    1,153

    Re: Power of UL POWER AERO ENGINES ?

    Quote Originally Posted by clanon View Post
    This number will be more important (at least for choosing the prop and pitch) than HP...since this is direct drive:
    218 Nm [160.8 ft.lbf] @ 2700 rpm
    Hp is the determining factor for aircraft performance as it describes work done actually. Direct drive or geared. Torque is only a measurement of force which by definition is not work.

  6. #6
    Registered User clanon's Avatar
    Join Date
    Jun 2007
    Posts
    532

    Re: Power of UL POWER AERO ENGINES ?

    I'm sure there's a lot more to aircraft performance than HP...
    "Do what you can, with what you have, where you are"

    (Theodore Roosevelt)

  7. #7
    Registered User Jan Carlsson's Avatar
    Join Date
    Jan 2009
    Location
    Sweden
    Posts
    1,484

    Re: Power of UL POWER AERO ENGINES ?

    218 Nm [160.8 ft.lbf] @ 2700 rpm
    That will be 82,7 HP (imperial) at 2700 rpm

    When calculating props for O-200 we use 85 HP

    I will check if we have some flight testing yet for the UL powered airplanes we designed and manufactured propellers.
    MYR likes this.
    Jan.

    A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away. Antoine de Saint-Exupery
    "Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible." Simon Newcomb, 1902

  8. #8
    Registered User clanon's Avatar
    Join Date
    Jun 2007
    Posts
    532

    Re: Power of UL POWER AERO ENGINES ?

    P=Power, kW
    T=Torque, Nm
    N=Engine rotational speed, rpm

    P= T*N/9550

    P=218Nm x 2700rpm/9550 = ~61HP

    Metric=9550
    Imperial=5252


    PS:Max power happens at higher rpm and lower or similar torque!
    "Do what you can, with what you have, where you are"

    (Theodore Roosevelt)

  9. #9
    Registered User rv6ejguy's Avatar
    Join Date
    Jun 2012
    Location
    Calgary, Alberta, Canada
    Posts
    1,153

    Re: Power of UL POWER AERO ENGINES ?

    All true but torque is not work. If I press on a ratchet having a 1 foot handle with 100 lbs. force, the torque at the center is 100 lb./ft. but without any movement, I have performed no work. Torque is a measurement of force, not work. HP describes the amount of work an engine can perform in a given time. This is why all engines are first rated in hp- in cars, aircraft, boats, locomotives etc. HP under the usable rpm curve determines how much work and how flexible a given engine design is. Many people erroneously believe that torque is somehow "pulling power". A PT6, RR Merlin or Wright R3350 are all rated in hp because the engineers who designed them know that this is the important rating to compare maximum work possible between engine designs.

  10. #10
    TFF
    TFF is offline
    Registered User
    Join Date
    Apr 2010
    Location
    Memphis, TN
    Posts
    3,270

    Re: Power of UL POWER AERO ENGINES ?

    I think torque implies movement. Angular change. Twisting a shaft although small is movement.

  11. #11
    Registered User clanon's Avatar
    Join Date
    Jun 2007
    Posts
    532

    Re: Power of UL POWER AERO ENGINES ?

    Yup!
    That's why always should have an RPM associated with it(and then you'll get torque) is plain Math
    The "magic numbers(9559 metric or 5252 imperial)" are a result of the conversion steps from rotational to linear dynamics.


    "Do what you can, with what you have, where you are"

    (Theodore Roosevelt)

  12. #12
    Registered User Jan Carlsson's Avatar
    Join Date
    Jan 2009
    Location
    Sweden
    Posts
    1,484

    Re: Power of UL POWER AERO ENGINES ?

    Quote Originally Posted by clanon View Post
    P=Power, kW
    T=Torque, Nm
    N=Engine rotational speed, rpm

    P= T*N/9550

    P=218Nm x 2700rpm/9550 = ~61HP

    Metric=9550
    Imperial=5252


    PS:Max power happens at higher rpm and lower or similar torque!
    It become 61 kW not 61 HP
    Jan.

    A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away. Antoine de Saint-Exupery
    "Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible." Simon Newcomb, 1902

  13. #13
    Registered User Jan Carlsson's Avatar
    Join Date
    Jan 2009
    Location
    Sweden
    Posts
    1,484

    Re: Power of UL POWER AERO ENGINES ?

    How to arrive at the 5252 konstant?
    550*60 = 33000 ft-lb-min
    it is 33000 / 2*phi = K 5252,113
    so metrik PS or HP is 75*60 = 4500 / 2*phi = K 716,2 if torque is kg-m
    and 716,2 * 9,81 = K 7026 if torque is Nm (= HP)
    conversion between kW and metric PS (HP) is 0,736 or 1,36 depending on the direction of conversion, kW have a lower Nr then HP

    Difference between metric HP 75 kg-m-s and Imperial is 550 lb-ft-sec = 76,04 kg-m-s = 1,01388672 ~ 1,4%
    making the conversion from kW to imperial HP 0,746
    Last edited by Jan Carlsson; September 6th, 2012 at 05:26 AM.
    Jan.

    A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away. Antoine de Saint-Exupery
    "Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible." Simon Newcomb, 1902

  14. #14
    MYR
    MYR is offline
    Registered User
    Join Date
    Sep 2012
    Location
    France
    Posts
    8

    Re: Power of UL POWER AERO ENGINES ?

    Quote Originally Posted by Jan Carlsson View Post
    I will check if we have some flight testing yet for the UL powered airplanes we designed and manufactured propellers.
    In France, several propeller builders estimate that the power of the 260i is between 80 and 85 hp. With the figure of 97 hp @ 3300 they failed as well several propellers.



    I have found this in a german website :



    This company says that the max power of the 260i is at 2700 rpm for 79 hp.
    Last edited by MYR; September 6th, 2012 at 05:24 AM.
    Sorry for the mistakes I can do. I am not an english speaker person.
    Forum about UL POWER (in french) : http://www.forum-ulm-ela-lsa.net/viewforum.php?f=443

  15. #15
    Registered User Jan Carlsson's Avatar
    Join Date
    Jan 2009
    Location
    Sweden
    Posts
    1,484

    Re: Power of UL POWER AERO ENGINES ?

    Interesting, is it factory information?
    Last edited by Jan Carlsson; September 6th, 2012 at 05:45 AM.
    Jan.

    A designer knows he has achieved perfection not when there is nothing left to add, but when there is nothing left to take away. Antoine de Saint-Exupery
    "Flight by machines heavier than air is unpractical and insignificant, if not utterly impossible." Simon Newcomb, 1902

+ Reply to Thread
Page 1 of 5 12345 LastLast

Similar Threads

  1. Vw power for Pietenpol.
    By Natty Bumpo in forum Volkswagen
    Replies: 13
    Last Post: January 13th, 2013, 06:18 PM
  2. Electric power...
    By mccdhash in forum Firewall Forward / Props / Fuel system
    Replies: 22
    Last Post: July 9th, 2012, 08:14 AM
  3. Inertia..need of power ?!
    By topspeed100 in forum Aircraft Design / Aerodynamics / New Technology
    Replies: 12
    Last Post: April 15th, 2012, 02:52 AM
  4. Air Power
    By Alan Waters in forum Hangar Flying
    Replies: 0
    Last Post: October 17th, 2009, 11:54 PM
  5. more power, more power!
    By StRaNgEdAyS in forum Hangar Flying
    Replies: 0
    Last Post: August 23rd, 2004, 04:44 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts