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Jez Billington

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Posts posted by Jez Billington

    Jet Provost 1.5metre Andy Blackburn PSS Plan

    in PSS Build Blogs

    Posted

    I’ve just had to add over 6oz nose weight to the JP to get it within the range of the new CG estimate. Really don’t know how that happened - I was clearly far too hasty to get it finished. The jig certainly makes things more scientific, but I’m now not fully convinced that even the cradle measuring device is giving a perfect reading. Need to build one of those see-saw devices to convince myself that it works 100%

    Edited By Jez Billington on 20/07/2020 16:54:17

    Jet Provost 1.5metre Andy Blackburn PSS Plan

    in PSS Build Blogs

    Posted

    Andy.
    I’ve always relied on finger balancIng to determine CG position but after talking to Pete he put me on to the string and plumb bob method that should prove far more accurate.

    From my side at least, I will only be able to confirm after flight #2 which will be hopefully far less exciting than the first.

    p.s. not sure what you mean by ‘slight pull towards the canopy’ - I would say a successful CG dive test is one which has a gradual unassisted pull out

    Edited By Jez Billington on 20/07/2020 12:51:46

    Jet Provost 1.5metre Andy Blackburn PSS Plan

    in PSS Build Blogs

    Posted

    It’s true, the model nearly ended up in Davey Jones’ locker, but not giving up when all seemed lost saved it, Hitting good slope lift with an unstable plane does seem to add some pitch stability for some reason. My model is quite a bit heavier than most (around 7lbs) which would not have helped the situation. That’s the result of adding flaps, nav lights and accidentally buying balsa thicker than required with the wing sheeting!
    I will check the decalage before the next flight and add some more weight to the nose. This will hopefully tame the model. Will try again at the Llyn in August

    Jet Provost 1.5metre Andy Blackburn PSS Plan

    in PSS Build Blogs

    Posted

    Finally managed a dry assembly today. Revealed a lot of small jobs that I thought I had already fixed - plus some new ones thrown in. It’s not a true scale colour scheme, but at least I should see it. Thanks to Andy for his pilots - super 3D print job. Chickened our of painting the fuz and used film instead - but it still took some doing. Not far away from a test flight now. Any volunteers to lob it?

    Jet Provost 1.5metre Andy Blackburn PSS Plan

    in PSS Build Blogs

    Posted

    Nice job Pete. Doing the covering job on mine right now - will share images when done. 
    Martin: I like the reptile-like Strikemaster scheme, but it’s well beyond the time allocation I’d give myself to cover a model. I don’t want to run out of steam at such a late stage of the build!

    Edited By Jez Billington on 15/01/2020 18:47:43

    Jet Provost 1.5metre Andy Blackburn PSS Plan

    in PSS Build Blogs

    Posted

    Progress on JP 1.5. Half a balsawood plantation now rests in the back garden. I think I used every sanding tool in the box. By far the best being Permagrit’s flat file with coarse grit.
    Decided to go for a concealed rudder linkage using square section carbon tube. Somehow Have managed to plank the bottom rear fuz without installing the snake supports first - dang!
    tomorrow will order canopy from Vortex (thanks Phil) and install Andy’s printed pilots.

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