Register

If this is your first visit, please click the Sign Up now button to begin the process of creating your account so you can begin posting on our forums! The Sign Up process will only take up about a minute of two of your time.

Results 1 to 9 of 9

  1. #1
    mick1404's Avatar
    Join Date
    Apr 2012
    Location
    Flinders ViewQueensland, AUSTRALIA
    Posts
    63
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    canard pusher config

    hello all,

    I am in the process of building a canard wing model withengine mounted at therear with apusher prop configuration and I was wondering if it would be benificial to mount the engine with a little 'up thrust' and' left thrust'asI have seenon someplans it seems to bequite common to haveengine with tractor configuration mounted with somedown thrust and sometimes right thrust.The plans don't call for it but I have heard this model I am going to build needs the foreplane elevator with some down elevator to keep the nose up.
    Any help would be greatly appreciated, thanks.
    suck, squeeze, bang, blow. Thermodynamics, love it.

  2. #2
    All Day Dan's Avatar
    Join Date
    Dec 2002
    Location
    MANHATTAN BEACH, CA
    Posts
    3,543

    RE: canard pusher config

    Mick, If you don’t mind looking at me as I age, here are the images of the canards I built. The first three were set up 0-0-0 and they all required an eight of an inch up trim. The fourth one had two degrees of up incidence in the canard and it required no trim. The last one has two degrees of up trim in the canard and requires an eight of inch down trim. All the engines have no thrust angle built in.

    Here’s a good website to help with the cg. I find it very accurate.
    http://adamone.rchomepage.com/cg_canard.htm

    Dan.
    Attached Thumbnails Attached Thumbnails Click image for larger version. 

Name:	Us53907.jpg 
Views:	72 
Size:	128.5 KB 
ID:	1865220   Click image for larger version. 

Name:	Lg16932.jpg 
Views:	43 
Size:	97.2 KB 
ID:	1865221   Click image for larger version. 

Name:	Va72880.jpg 
Views:	35 
Size:	114.7 KB 
ID:	1865222   Click image for larger version. 

Name:	Cw63318.jpg 
Views:	38 
Size:	107.3 KB 
ID:	1865223   Click image for larger version. 

Name:	Bn77043.jpg 
Views:	50 
Size:	129.1 KB 
ID:	1865224  

    Dan

  3. #3
    Lnewqban's Avatar
    Join Date
    Apr 2007
    Location
    South Florida
    Posts
    4,034
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: canard pusher config

    All the forces acting over any airplane make it rotate around the CG, if they have a combined lever respect to that point (thing spatial point here).

    Undesired rotations is what the down and right deviation of the thrust achieve for tractor configuration.

    Down thrust helps reducing or eliminating the lever respect to CGs that are high, so the airplane doesn't show a nose up tendency with power application.

    Right thrust helps increasing the lever respect to the CGs (located over the center line, if the plane is laterally balanced). By doing that, the designer introduces a yaw moment or torque (to the right) that compensates for the left yaw moment associated to the P-factor and gyroscopic precession of the propeller, so the airplane doesn't show a nose left tendency with power application, especially for tail draggers.

    http://en.wikipedia.org/wiki/P-factor

    http://en.wikipedia.org/wiki/Precession

    Consider how those forces could affect your design for deciding on any thrust angle.

    If yours is a trike, you will not need much, if any, left thrust.
    If your engine is about the same level than both wings, you will need zero upthrust.
    Lnewqban - "God will not look you over for medals, degrees or diplomas, but for scars. He has achieved success who has worked well, laughed often, and loved much." - Elbert Hubbard

  4. #4
    Villa's Avatar
    Join Date
    Aug 2003
    Location
    Wilson, NC,
    Posts
    2,052
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: canard pusher config

    Hi k1404
    On my Canards with Pusher Prop, I mounted the engine with zero side thrust and no vertical offset. The Canard wing was mounted with a few dergees + incidence. Flew great. I suggest you learn to go to full down elevator as soon as the mains touch down during a less than perfect landing. The Canard has a tendancy to have the front end bounce up during a high wind rough landing. A few times mine has gone to near vertical just a few feet off the ground. Without a plan, you are done!

  5. #5

    Join Date
    Nov 2001
    Location
    King Salmon, AK
    Posts
    2,398
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: canard pusher config

    That Trimotor looks awesome! How did it fly? I could swear I saw some of those planes in RCM or MAN as construction articles. Are they your designs and are they published?

    Don

    ORIGINAL: All Day Dan

    Mick, If you don’t mind looking at me as I age, here are the images of the canards I built. The first three were set up 0-0-0 and they all required an eight of an inch up trim. The fourth one had two degrees of up incidence in the canard and it required no trim. The last one has two degrees of up trim in the canard and requires an eight of inch down trim. All the engines have no thrust angle built in.

    Here’s a good website to help with the cg. I find it very accurate.
    http://adamone.rchomepage.com/cg_canard.htm

    Dan.
    Revver Brother #94

  6. #6
    All Day Dan's Avatar
    Join Date
    Dec 2002
    Location
    MANHATTAN BEACH, CA
    Posts
    3,543

    RE: canard pusher config

    Thanks for the compliment hattend. All five of the canards flew great. A couple of them had hair raising first flights, that I survived, and was able to tame them with an adjustment to the CG, Yes, the first three were published as construction articles in Flying Models. Dan.
    Dan

  7. #7

    Join Date
    Jan 2003
    Location
    Vandalia, OH
    Posts
    94
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: canard pusher config

    I added the thrust changes. I don't think it made much of a difference. The plans called for it though.

    http://www.youtube.com/watch?v=vX1d8JgIXKs

    I am running with bad internet. Use the link to see my latest plane.

  8. #8

    Join Date
    Jan 2003
    Location
    Vandalia, OH
    Posts
    94
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: canard pusher config

    I added the thrust changes. I don't think it made much of a difference. The plans called for it though.

    http://www.youtube.com/watch?v=vX1d8JgIXKs

    I am running with bad internet. Use the link to see my latest plane.

  9. #9
    mick1404's Avatar
    Join Date
    Apr 2012
    Location
    Flinders ViewQueensland, AUSTRALIA
    Posts
    63
    Gallery
    My Gallery
    Models
    My Models
    Ratings
    My Feedback

    RE: canard pusher config

    thanks mate, that makes sense but as the plans dont call for any thrust angle left or up, I will stick to what the plans call for, sorry, I was just thinking outside the box a little.
    suck, squeeze, bang, blow. Thermodynamics, love it.


Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
All times are GMT -6. The time now is 06:41 PM.

SEO by vBSEO 3.6.1 ©2011, Crawlability, Inc.