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Thread: p factor in 912 Blade

  1. #1

    p factor in 912 Blade

    Is it common for a 912 Blade to cruise at about 5 degree list to the right? I have a 912 that seems to have a cart that is divorced from the wing and twists and turns as power is added. This is unpleasant and I would like to correct it. I cannot level the cart unless I reduce power enough to loose altitude rapidly as in landing. I understand that the best way is counter this is to remount the engine with a 2 degree (or so) rotation CCW from the center line. Has anybody done this? Has anybody made finned wheel pants to add directional stability? How about a deep fairing on the pylon as my old Pegasus Sport had? Any other ideas that you British microlighters have? There are very few 912 Blades in the USA so I need your ideas! Thanks,

    Karey Love

  2. #2

    p factor in 912 Blade

    Yes.
    I'm sure you're right about offset curing the problem but I'd be interested to see if anyone has done it (you should ask Roger Pattrick).
    Do check to see if the upper seat frame hasn't moved across in the 4 plastic clamps.
    That can upset the symmetry of the trike, and also, ultimately, result in a propstrike to one of the spats on a bumpy ground run.
    (Has your Blade not already got finned wheel spats/pants?)
    Dave

  3. #3

    p factor in 912 Blade

    Dave; I have spoken to Roger P. about this issue and he did mention the seat frame, shifting possibility but my seat is symmetrically placed. The Blade does have spats that are minimally finned. I taped on some plastic sign board s to create a test fin and that DID lessen the cart lean that is at issue. I think I will fabricate a tall fin onto my wheel spats. I might even remove the 912 and have corrective motor mounts made. But, GULP....that's a bit of a big deal for me. I am hoping that other 912 Blade flyers will comment on their experience with the cart lean issue. (Dave McGauley --- where are you??)

  4. #4

    p factor in 912 Blade

    Thanks for the tip. I have made adjustments to both upper motor adjustors and look forward to flying it when the weather cooperates.

    Karey

  5. #5

    p factor in 912 Blade

    any luck karey?

  6. #6

    p factor in 912 Blade

    Here's a little background on my issue as a preface to my answer to you and others:

    I bought a 1998 vintage 912 Blade and was surprised and unpleased with how it flew. When I compared it to my old Pegasus 503 Sport, the Blade was a dissappointment. It has what I call extreme P-factor or maybe precession where the card learns to my right when flying at level cruise and also gyrates with a mind of it's own. I just don't feel like I'm in control as much as I want to be. It's a little like being strapped into a roller coaster seat and committing to a ride; fun but passive. So................

    I started by modifying my wheel pants by adding tall fins (to create drag and add stability to the cart). Well that went nowhere. On my first landing I contacted the left wheel hard onto the tarmack and the wheel pant kissed my Warp Drive prop (actually more like a French kiss!). The play of the entire wheel pant, mounting bracket and axle assemblies allows excessive "slop" so the pant (with a fin) is dangerous. Luckily, my prop survived just fine and the finned pant was just a wooden prototype that is now returned to the original design. Lesson learned. So.................

    I am now making new engine mounts for the purpose of rotating the 912 2.25 degrees to the left (CCW). I am replacing the 6 Lord mounts with new ones and hope to finish this project today (Saturday-a play day for me!) I will post the results. But, my BIG question is stilll................

    What is the experience of all you 912 Blade pilots in Great Britain concerning the Blade and its flight characteristics? What have you to say about this trike? Is this just me or my trike or is this issue common with ALL 912 Blades? There is nobody I can find in the USA that has a 912 Blade. There's a few guys in Mexico but the few posts I've had with one guy went nowhere. I have contacted Roger Pattrick and was told that the Blade does "move about under the wing" more than did my Pegasus. I have tried adjusting the top motor mounts but that did not correct the problem So, your feedback is desired!

    Karey

  7. #7
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    p factor in 912 Blade

    Hi Karey, I have flown at least six 912UL powered Blades, and they have ALL shown the characteristics you describe (wing seems to be following a different path to the cart (UK "Trike")
    I am no expert regarding Flexwing design, but would suggest it is a combination of thrust line and hang point arrangement.
    Regards, Kevin.

    PS. Only 5 degrees? you must have good one!

  8. #8
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    p factor in 912 Blade

    Karey why dont you post this topic under the "Technical Questions and Answers" section....many more Blade owners or ex Blade owner will come across it there,

    Please let us know how it fly's after you finish your work on it...good luck.

    Nick.

  9. #9
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    p factor in 912 Blade

    Paul I remember during my training which was on a 912 Blade....don't remember much about flying it as it was a few years ago now...but I remember my instructor saying the you could steer the Blade aerodynamicly a small amount with the nose wheel....would this have any effect with this problem,

    I suppose your hang bracket and associated bits are not sloppy Karey....just a bit in each component adds to quite a bit,

    I wonder if those Blade spats could add to the problem rather than alleviate it....is it worth test flying without them fitted.

    Nick.

  10. #10
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    p factor in 912 Blade

    The wheel spats fitted as standard on the blade really do aid stability in flight. The 912 always takes a lurch to the right on takeoff (a mixture of torque and crap engine mount design) but, if all is properly lined up, seat frame, engine mounts etc. and there is no slop or twist in the hang bracket they should fly straight hands off. If the wing is properly set up you should get 8-12mph speed difference trimmed slow to fast on the middle hole. Enjoy!

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