Duncan's got a Flea

Discussion in 'Aircraft Design / Aerodynamics / New Technology' started by rtfm, Aug 3, 2017.

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  1. Jan 6, 2018 #561

    rtfm

    rtfm

    rtfm

    Well-Known Member

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    Hi,
    I've been silent for a while (some might consider that a blessing... ha ha) but I though I'd update my build progress. I have a number of things on the go at the moment - but none of them have been completed to the extent that they deserve individual reporting.

    First, I've completed the structural work on both the fin and the rudder, but have not covered either. The reason for this is that the rudder hinges are going to be rod end bearings, fastened to the rudder with nut plates. These have to be inserted before I cover the rudder. And I'm having some difficulty sourcing the nut plates. Rod ends - no problem. But here in Aussie, most people seem to be unaware of what a nut plate is. So if I can't scrounge two locally, I'll have to import some. (Fin on right, rudder on left). Fin = 845g, rudder = 413g I am going to cover both with sheets of 1.8mm ply. This is a bit heavier than fabric, but FAR less hassle, cleaner lines and it will contribute to the structural integrity of the pieces.
    7-01-18 Fin and rudder.jpg

    Next, I've built the floor and sanded it to shape, but have not bonded it to the airframe yet. Reason: First, I need to both bond in the side braces so that I can cut out the floor to accommodate them, and then I need to figure out where to cut out the footwells. To do this, I have to sit in the seat and see where my feet end up. I have also been thinking that I might cut the floor in two (longitudinally), which will allow me to very easily fit the floor around the side bracing. When both sides fit like a glove, I'll bond the two together (top and bottom) with a strip of plywood - I could even stain it a different colour, and make a bit of a feature of it). The floor is constructed from 1.8mm ply/10mm Airex foam/1.8mm ply. It is as rigid as anything. And weighs very little.
    7-01-18 Airframe with floor.jpg

    Then I've been working on my composite seat. What I did was to sit in an old car seat covered with a layer of plastic and then a few layers of glass fibre till the glass set. It took HOURS! And got bloody hot. I won't try THAT again - I ended up with burns on my bum. Anyway, what I ended up with was a very body-hugging seat which (unfortunately) was a bit lop-sided. I hadn't realised that my left leg wasn't at the same level as my right, and I think I might have been sitting crooked. Either that or my body is very mal-formed indeed. Anyway, the seat was nice, but needed a lot of filling and sanding to get it even. I think I've got it, so now I have to lay on a few more layers of glass and bog, and sand the hell out of it. My next problem is that I have six or seven drums and containers of different types of resin and hardener, and can't remember which goes with which. I knew at the time, but my hand-written instructions on the containers seem to make no sense at all. So I'll have to wait till tomorrow to phone the suppliers and ask then what goes with what, and what the mixing proportions are. The plan is to make a CF/10mm Airex/Glass sandwich from the mold. I have everything in the shop, so I'm ready to go.
    7-01-18 Seat.jpg
    Another view (with a layer of glass ready to be applied.
    7-01-18 Seat2.jpg

    My collection of resin/hardeners...
    7-01-18 Drums of resin.jpg

    Finally, I've built the two mounts for the main gear. The gear itself will be 16mm aluminium plate sandwiched between two channels of aluminium angle. The angle is bolted to bulkheads constructed from 3 bonded layers of 6.5mm plywood. Not very light, but super strong. I don't have the plate yet - waiting for an influx of funds - so I'm using 16mm MDF as a template. I hope everything fits when I finally get the plate.
    7-01-18 Main gear mounts.jpg

    So, as I say - a fair amount of progress, but not a lot to show for it. Oh - and I've been trying to keep on top of the Build Manual. But as I change my mind about how to actually build the various bits, I have to update the notes, take different photos and so on. It's a big job, and definitely a work in progress.

    Regards,
    Duncan
    [UPDATE] I have now (this morning) bonded in the main gear mounts.
     
    Last edited: Jan 7, 2018
  2. Jan 7, 2018 #562

    rbrochey

    rbrochey

    rbrochey

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    Interesting post Duncan! Nice work as well... I like the fleas too and if I were to build one it would be the HM 293 RG with the slightly longer fuselage. Those plans are nicely done.
     

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