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Thread: Blade 912/582 climbing problem

  1. #1

    Blade 912/582 climbing problem

    I purchased a Blade which started life as a 912, then had the engine removed and a 582 blue top fitted. The engine mounts, fuel tanks etc. were all changed over.
    My problem is that I haven't had a decent flight with it. A typical flight is - full revs for take-off, gets airborne no problem then at about 300ft I have to reduce the revs as the a/c is climbing at over 1000 fpm with the bar as far back as I can get it and the speed is dropping towards stall. At around 50 mph it stops climbing, but I still have the bar back into my stomach. I've tried leaning right back into the pax seat to see if I can get the bar back further, but it's b***** uncomfortable and didn't achieve anything.
    I was flying without any ballast, had 60 litres (42 kilos) in the tank, + me (100 kilos) and with an a/c weight of 190 kilos, this gives a weight of 332 kilos, surely enough for solo flight (max auw 390 kilos).
    The trike is on the front hang point, battens as profile, trim set for take off, (putting it on cruise made no difference).

    I really don't understand this, I'm literally flying the a/c on the engine revs except for landing and take-off, with the wing staying in one position during flight.

    The guys at the airfield are puzzling over this, I just wonder if anyone has experienced this or have some ideas (prop thrust line below the C of G?)

    Cheers,
    Ross

  2. #2

    Blade 912/582 climbing problem

    Ross,

    Try moving it.to.the rear hang point and back off the throttle a little.

    I used to be able to.climb.at 1800ft/m with the 912 in it and I was nearer 100kg.

    I always used the front hang point as I toured around the Uk a lot, but you may find it nicer to fly in.the rear.

    Good.luck.in sorting.it.

    Steve

  3. #3
    Diamond geezer 500 Club
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    Blade 912/582 climbing problem

    Whats it revving to max...

    Dont forget Roger at P+M is ever so helpful.

  4. #4

    Blade 912/582 climbing problem

    Steve - Quite right, it's your old a/c with a 582 blue top. I'm assuming that the only difference between the 912 & 582 blades are the engine mounts and associated equipment. The only changes I've made were to take the reflex out of stb'd battens 9, 10 & 11 as it was causing a left turn. I'm wondering if the lighter engine is causing the problem.

    Nick - 6800 rpm, and thanks, I'll give him a ring.

  5. #5

    Blade 912/582 climbing problem

    Spoke to Graham at P&M - he thinks it could be a "me" problem, i.e. not being used to flying a blade (I trained on a quantum) However he suggested checking the prop pitch and taking off at 6200 - 6400 rpm instead of "flat out" at 6800. Also mentioned that the blade 582 should cruise at 60 mph at around 5000. Hope to try this out soon - watch this space

  6. #6
    Diamond geezer 500 Club
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    Blade 912/582 climbing problem

    Dont forget...our std microlight tachs are not to accurate...cant beat a hand-held for testing the max static RPM,

    These are great for your toolbox...very accurate.

    At 6800 you could be over revving by around 400rpm...going by the rotax manual,

    http://www.ebay.co.uk/itm/Spark-Plug...item5d4bf27ea4

  7. #7

    Blade 912/582 climbing problem

    The Blade has always been a bit like that, so your Quantum experience will only make it seem worse.
    Not sure what you mean about 'approaching the stall' - is it really, or does it just feel like that due to the high climb angle?
    Did you remove reflex that had been previously added (ie back to factory setting), or have you put in some 'negative' reflex?
    You should never do the latter - add more reflex to the other side instead.
    What's hands off trim speed?

    Dave

  8. #8

    Blade 912/582 climbing problem

    Dave - "Not sure what you mean about 'approaching the stall' - is it really, or does it just feel like that due to the high climb angle?" - Yes and no, high climb angle and speed dropping because of it. Reflex was back to factory setting.

    Nick - got one on order, cheers, and thanks for pointing me towards P&M, Graham was very helpful pointing out facts which have almost solved everything.

    The update is, as Dave pointed out "The Blade has always been a bit like that, so your Quantum experience will only make it seem worse". Taking what Graham at P&M told me, I reduced take-off revs to 6400 instead of 6800, at 400ft reduced to 6000 rpm and climbed out at 500 fpm at 45 mph, at 2000 ft, reduced to 5000 rpm and I could fly "hands off" ,(it was a lovely day for flying on Friday up here), at 52 - 55 mph with the bar about 4 inches from my chest. However, as soon as I tried to increase speed - yup, I had a lovely view of the sky as I couldn't get the bar back.

    So my problem was, not being used to the blade, trying to fly at too high revs, and lack of experience - but thanks to you guys I had two great flights on Friday, one trying all the information out and the second a purely self-indulgent cruise to Pitlochry and round the mountains.
    Now I have to figure out how to trim the wing to fly faster - tips up or down?

    Cheers all
    Ross :jumpin:

  9. #9

    Blade 912/582 climbing problem

    If you increase the lift at the tips (actually, I believe the tips are effectively at a negative angle of attack in normal flight, so it's a case of reducing their down force), the wing will fly faster - so it's tips down. Increasing their angle of attack. HOWEVER - all this will do is push the bar back and increase hands-off speed. If the bar has nowhere to go (it's already in your stomach), that doesn't help much. I sometimes wonder if the factory deliberately set the bar back to physically limit nose down pitch availability. I think you need to talk to P&M some more, or locate a Blade 'guru' - probably an instructor or, at least, a more experienced check pilot than me on Blades.

    I do think that 6800rpm is high. I suspect your prop is a bit fine. Do check it accurately.

    Dave

  10. #10
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    Blade 912/582 climbing problem

    Nick Axworthy wrote: Dont forget...our std microlight tachs are not to accurate...cant beat a hand-held for testing the max static RPM,

    These are great for your toolbox...very accurate.

    At 6800 you could be over revving by around 400rpm...going by the rotax manual,

    http://www.ebay.co.uk/itm/Spark-Plug...item5d4bf27ea4
    I'd like to echo to Nick's warning - I had the same problem, my 447 was "over-revving" (6800 on take -off) until ... I checked revs with optical tachometer (on the ground of course). The error was about 400 rpm.

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