Announcement

Collapse
No announcement yet.

Lou Andrews Aeromaster Too, from AAMCO kit, built for electric ...

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

    Lou Andrews Aeromaster Too, from AAMCO kit, built for electric ...

    For those wishing to know exactly what an Aeromaster Too is; just as starters, here's the box that was delivered...



    A cursory inspection indicated that all is complete and intact, and now the fun begins. The instructions are printed on the plan itself, which is both handy and an inconvenience. They start with a stark warning about preparing the cabane structures, and then the fuselage building is described. Here's the fuselage plan (there are two more, for the wings...) spread out as best as I can on the building board...



    The sheets with the relevant parts for the formers have been isolated, and each former half identified and marked, by comparing to the plan. A bit tricky, as there are a couple that seem identical at first, but careful measurement shows a 2mm difference in height. When I said I wasn't going to rush this..!
    I'm going to assemble the fuselage gradually; firstly as a dry fit, to be sure that I've got all the parts ready and that I fully understand the process. I'll need the cabane struts very early on, so I took the pieces from the box, again comparing to the plan, and worked out which piece goes where. Puzzled, at first, until I realised that some of the piano wire is, in fact, two pieces in one, that need separating, with the aid of a triangular file. I have such files, but I also have a Dremel cutting disk, which made the separation much easier and cleaner. I was also puzzled by the insistence found elsewhere in other Build Logs that one makes a Right and a Left cabane strut. It seemed to me that these parts were symmetrical, until, with close inspection, I noticed a very slight second bend in the 'v'-shaped rods. This is not highlighted enough on the plan, nor the instructions, and I would have easily fallen into the trap. (Having said that, I'm capable of falling into the trap just the same; clumsy as I am..!).
    I spent much of a long career as an electronic technician, and soft soldering holds little in the way of secrets, for the most part. It's been rare, however, that I have elements of this sort to work on. A trial was required, to see quite how I was to get the cabane mounted, cleanly, accurately and with the strength needed. To this end, I cleaned a part with acetone, then gave it a decent rubbing with sandpaper, then another acetone wipe. Meanwhile my trusty Weller station was coming to temperature, so I weighed down the wire and had a go at tinning it. Almost, but not quite. My 50W iron managed to tin the rod, but really only just, and I don't think it'll be up to doing a whole wrapped join, with the extra heat dispersion engendered. A nice try, but I've ordered a rather more primitive, but rather more powerful, 100W iron, which should arrive before the week-end. Here's the mock-up I did to see how I could do the binding and soldering when the iron is delivered...



    Meanwhile, I'll prepare the former halves, which need joining and reinforcing, and try to find the ply strut supports in this box of sticks.
    Enough for this evening; more as and when things advance...

    #2
    The fuselage formers are supplied in halves, by pair, and are to be butt-joined. They are then reinforced with cross pieces. My question was to have been 'Are these cross pieces die-cut, or supplied stick, or to be cut from scrap..?'. The answer was on the plan; they are 1/8 x 1/4 (typically...)...



    I found strips of the sort bundled in with the stringers, and they seem to be mighty beefy to me. I've therefore taken the liberty of using old scrap sheets from my stock of old scrap sheets (stop laughing..! Don't you all have old scrap sheets that you are loth to dispose of..? No..? Hmm...)...



    From a selection of these 1mm5 sheets, I've stripped 6mm strips. The 'A' former has been carefully released from its prison, the slightly furry edges buffed, and the two halves lined up, and held with masking tape...



    ... turned over, and the strips checked for position ...



    All that remains is to wrack my brains for something with which to lest the assembly once glued up with wood glue. Now, what could I possibly use, I wonder..?



    A happy inspiration strikes me, as I happen to have a weighty lump hammer to hand.
    Only the upper and lower strips are glued, for now (plus, of course, the butt joint, hinged open with the tape and glued, then hinged shut...), as the middle pieces need more careful alignment, and the system I've employed is not the most precise. No great matter; they'll wait their turn patiently.
    There, now; did I do right..? Am I spoiling the ship, already, for a few measly grammes..? It's not too late to have me follow rigorously the instructions (although 'typically' gives me some leeway, I thought...). The first step is taken, though, which is a major one, if one wishes to stay the course. No, I shan't be boring you with every gluing of every former, but I thought that the Taking Of The First Step was worth a post.

    Edit: Here's the clamping of the two other strips, by more traditional means ...

    Comment


      #3
      After much re-reading of the instructions and the plans, plus other build logs, coupled with rooting out little pieces of wood from the small mound supplied, I finally worked out how this 'Box-Lok' construction works, especially the cabane strut supports. Several 'dry runs'; here's a final check that I'm putting the right pieces in the right place ...



      ... and now the grooved strut supports are glued into the 'Box-Lok' foundation (it's the inside flanks of the fuselage, really, but Ssshh..! 'Box-Lok' 'rings' better..!) ...



      Of course, it would be better still if these critical pieces were weighed down, to be sure they are firmly flat and in place, so ...



      ... we've just the tool for the job...
      While that's setting (wood glue, of course...), we can get cracking on the soldering. Here's the set-up before starting...



      The formers, all glued up, can be seen stacked up under press at the rear. The lump hammer has been 'borrowed' from there, as they are now finished. I clean (again...) the piano wire parts, and tin the centre of the 'V' of the wing support and the cabane. Once cooled down enough to be manipulated, they're cleaned again, then, held with pincer clamps, the first wrapping is done. The supplied wire is easy enough to use, and is just the right length...



      It's been cleaned (rubbed through an acetone swab...), and is supplied already tinned. All that's needed now is to apply heat, and 'sweat through' my cored solder. Hmm... Not so easy, I fear. It seems to be taking an awful lot of heat to get the wrapping, and its underlying piano wire, up to the point where the solder just 'flows'. It's not helping that the iron (brand new...) seems to want to burn off the solder core, leaving an ugly dark residue. I manage to get the solder to flow in the end, but it's not as pretty as I would have liked. This is the final result, both sides...





      Once cooled, it appears to hold (I can't unwrap it, of course, and it would take quite some force to twist the top piece away...). There will be two more wrappings, one at each end, before we're done, so it is probably sound enough. Still, I'm disappointed that it was so slow to decide to cooperate, and much more messy than I'm used to. Not the right solder..? Possibly (no, it's not this lead-free stuff, it's pukka electronic flux-cored, which I've been using successfully for decades, but not for work like this...). More, better, different cleaning..? I don't really know what more I could do, as I'm sure I've followed all the recommendations (wiping away the protective oils with acetone, a good sandpaper rub, not touching the surfaces with my fingers...).
      Enough for tonight, anyway. The test was really to see just how easy, or problematic, this wrapping really is. I need to have at least the lower wrapping spots tinned on the struts before gluing them into the fuselage; all the other wrappings are to be done towards the end, in any case, but it's now that I need to have this process under my belt. I'll sleep on it, and read up some more tomorrow. It's not too bad, but could be much improved, I'm sure.
      To be continued...

      Comment


        #4
        My new soldering iron arrived, and I bought a jar of flux for plumbers from the hardware shop, along with some '000' steel wool. What a difference..! A rubbing-down with the steel wool (wearing gloves; it's unpleasant for the skin...), then a moderate dose of flux, the new, 100w iron made short shrift of the job. In only a few seconds, the solder flowed quite smoothly over the piano wire, and, once the windings were ready, had the solder flowing just as easily through the whole join. Very pleased with the result...



        I'm not sure about continuing the construction, but will probably connect those diagonals, after checking that they correspond to the fuselage supports. I'd rather get as much soldering done away from the wood, for fear of burning something, as long as it's going to marry up correctly. To this end, then, I'll need to prepare the fuselage flanks to receive the cabane. Here, the 'Box-Lok' foundation is glued to the flanks...



        ... and the lower wing beds are glued to them...



        That's enough for tonight; next step is marking out the position of the formers, and maybe soldering the cabane diagonals. We'll see...

        Comment


          #5
          The are moments when a lump hammer is simply not enough ...



          The top of a cabane strut can be seen, just about, poking out from below the right-hand end of the beam. The other strut is equally hanging down at the other end. The struts are now glued into a 'sandwich' made from the pre-formed blocks of the 'Box LoK' fuselage flanks. The instructions recommend this process for letting the glue go off overnight. I had finished all the strut soldering that can be done without having the fuselage assembled, and was pleased with the way it went, thanks for a great part to the helpful hands of Our Daughter, very much more nimble-fingered than Charlie, my crocodile clip 'third hand'. He's fine for holding a plug while soldering, but not so useful for this Chinese puzzle of a cabane..!
          Tomorrow, when the weight is lifted, I may be able to glue up the next parts of this Box-Lok, and think about installing the formers. I'll sleep on it.

          Comment


            #6
            Here's the result of the cabane gluing-up. Firstly, flat on the table, now that the lesting beam has been lifted ...



            ...Then mounted, in station, as they'll be flown ...



            That last picture is only a mock-up, of course; I'm waiting for a motor to arrive to see what modifications need to be done to the nose, as it's to be electric, not internal combustion. Should arrive tomorrow or Saturday.
            I've unfolded the plan for the wings, and may start seeing how to proceed there; meanwhile, on with the Curtiss Condor build, as I've received the 3mm sheets ordered...

            Comment


              #7
              Here's the motor, delivered with a nice spinner and sturdy mounting cross-plate...



              Our Eldest is happy enough to oblige me in routing out the 'chin' block, to allow for the motor's rotation, while I reduce the redundant length of the original engine bearers,..



              This is an 'exploded view'; the milled-out chin block is clamped for now, and the bearers are shorter. By pure coincidence, I have a set of stand-off pillars, which are exactly the right length for aligning the prop plane ...



              ... and this is how it will look once all is fixed in place...



              For the moment it all seems neat and tidy; the questions of 'Is it powerful enough' and 'Does it need more cooling' are still unanswered. I've not got a suitable prop yet, so can't do a bench run to see about current drawer (and so wattage...); that'll have to wait a week or so. Still, it's all ready for the gluing up of the fuselage, if there are no hidden traps. Thoughts, folks..?

              Comment


                #8
                Here she is, with the Box-Lok all glued up now. It seems to be right: it's hard to see how one can end up misaligned if this system is followed as written. I'm impressed.



                The motor is not glued in, of course, merely mounted so that the bolts are guaranteed to be lined up. I've a carbon cross motor mount which fits perfectly behind the firewall, which will serve splendidly when I finally tighten it all up. Right now the bolts are only just long enough; I'll order some 60mm M4's, and a box of M4 Nyloks while I'm at it.
                The next step is to read through the docs again (yes; it's never too many times...) in preparation for the installation of the fuselage formers, which will establish the turtle deck rear end. More fun to come, then..!
                PS: I've ordered a couple of 13x7 electric props, and a pair of 14x7, too. Not stocked in EU Hobbyking depot, so I'll have to be patient and wait for the slow boat from China. I'll then be able to run the motor through the amp-meter and see what it can do. I'll report back when they arrive...

                Comment


                  #9
                  One thing is sure: I'll never willingly choose to use two-part epoxy glue if there is any credible alternative. I'd rather use melted butter, if it would do the job, or plaster of Paris..! Still, there are occasions where it's the only stuff, such as here, where ply formers are to be glued to the piano wire cabane struts. Here's the operation finished, and not too soon ...



                  With any luck, the slips of baking paper will prevent the stuff from adhering to the clamps. I hope it doesn't adhere to the baking paper, though..! I'll know tomorrow; I'll leave it a full day or so to harden.

                  Comment


                    #10
                    Next step is to join the rear of the fuselage, with an off-cut of trailing edge, making sure that the two sides are square and symmetrical...





                    It looks OK to me. Now for the turtle deck formers, the first being just behind the pilot position. I thought it best to glue the two formers together before gluing into place...



                    The next part has complications. The former has to marry the rear of the 'Box-Lok', but I don't have sash-clamps long enough to hold it firmly. Gravity will have to suffice, in the form of the lump hammer (and its smaller cousin...), weighing down a block of wood over the former, whilst the 'plane is perched on its nose, held steady between a couple of flight cases...



                    Not very conventional, but needs must... Once set, we may proceed with the following former, clamped with more traditional elastic bands...



                    The other formers follow, after a suitable interval to allow the predecessor to set. When enough are in place (one more left to do...), I can start on the front formers. These have the complication of sandwiching the piano wire struts and ply cross-pieces. Wood glue would suit the join to the ply, but I decided to use Gorilla Glue for this, to get a bond with the piano wire. I learn from this the origin of the name 'Gorilla Glue': one needs the force of a gorilla to squeeze the stuff from the bottle..! My right arm is not good right now; a spot of tendonitis (tennis elbow...), so I've been using the left arm/hand as much as possible, to rest the right. No dice for this glue; I have to use both hands and wince as the stuff oozes out slowly. One done, though ...



                    ... I'll do the other when I've rested the sore arm a bit more.
                    It's taking shape, though; I've very pleased with the quality of wood in the kit, and equally the fine cutting. The pieces don't fall out from their sheets, but need little persuasion, and no trimming. So far so good, then...

                    Comment


                      #11
                      Another task requiring patience; here's the first, square 1/4", stringers going in ...



                      ... and side stringers ...



                      Meanwhile, I've come across what I believe to be an error in the cutting for this kit. The sheet for the curved upper fuselage, called a 'cowling' in this kit, is pre-cut with slots for passage of the cabane strut wires. The cowling is reset behind the first former, perched on the engine mount. The slots, however, are cut too far back, such that the front protrudes over the former, instead of nestling in just behind...



                      My solution has been to widen considerably the slots...



                      allowing the cowling to move back, and settle in its place ...



                      The sheet will lie flush with the foremost former, supported by the slightly recessed former and stringers just behind.
                      That's for a bit later, of course, once all the stringers are in place. I wait patiently for each set to dry before installing another batch.
                      Another error; this time of my own doing. The turtledeck formers have been assembled, using scrap sticks, and glued into place. The first, just behind the cockpit, sets the scene for the others; these reinforcing strips are to the rear, allowing the former to lie flush with the end of the Box-Lok. All well and good, except for the rearmost former, which has to be the other way about (reinforcing strips to the fore...) as the tailplane has to butt up to it, and the strips would prevent that. This minute detail is, in fact, apparent after close inspection of the plan side view, but is not highlighted, and so Muggins here has gone and done it wrong. D'oh..! Once I'd 'twigged', my only reasonable recourse was to carefully slice away the offending reinforcing strip, thinking awhile that there, at least, is a bit of weight gained..!



                      No great harm done, then, but it underlines the necessity to study carefully, and, in my case, several times, all of the instructions, photos and plan details, preferably two or three steps in advance of the current task. Even then, I'm not certain to be error-free..!
                      All this while, I'm cogitating, trying to imagine exactly how to make the modifications needed for battery access etc. For the moment, my thoughts tend towards finishing this cowling, then cutting it away to become an access trap, or hatch. I've seen photos of others having done similar to their 'plane when converting, or building, as an electric version. I could also cut a trap into the underside, but I'd be happier, I think, working through the top. It may require removal of the upper wing, though. Hmm... No rush, but will have to make a plan soon.
                      The fin and tailplane are also marked for creation soon. I had envisaged using the stock 1/4" sheet, and removing the innards, but I'm now leaning towards a completely new frame, copying the form on the plan, but made with my own stock of sticks. I'll do a dummy layout first, to see how it looks, then decide...

                      Comment


                        #12
                        I'll need a hatch; here's what I'm working towards... I've a balsa sheet to go inside the fuselage, the whole length of the Box-Lok section (from the cockpit to the firewall...), which will serve as a base for the battery, Esc, Rx, servos etc. I'll probably slot holes in it, partly for lightness, but more to let air flow through, and provide attach points for tie-wraps and such. It will also serve to hold rigid the fuselage, as I'll be cutting away the cross-pieces between the cabane struts. To access this from the top, I'm doubling up the end formers for the cowling. I've cut them out by hand, after tracing the outline from the original kit sheet onto some stock sheet I have. The stringers will be glued in place, but not to the original ends. It's been prepared; in the photo can be seen the plastic sheet to prevent these new formers from being glued to the original end formers...



                        Once the stringers are all glued in, I'll be able to carefully cut through the arches between the cabane struts, to free the entire hatch. I've not yet decided whether to use the sheet for this cowling/hatch, or simply film & tissue it, to match the way I'll be covering the rest. I've thinner sheet, too, which could be used; we'll see. I haven't decided how to attach it, either, but it'll probably involve magnets somewhere.

                        A short time later...

                        Here's the stringers in place, all glued up and clamped...



                        Tomorrow, the lower rear stringers...
                        Last edited by Dad3353; 08-29-2018, 12:38 AM.

                        Comment


                          #13
                          I've decided to have a coulpe of dowel 'studs' at the fore of the hatch, and a couple of magnets at the rear. The balsa former won't be strong enough for studs, so I'm 'recycling' the ply engine bearer excess as dowel reinforcing. A bit of thinking is required to jury-rig a clamping system (no lump hammers here..!) ...



                          A wider view; all the stringers are now fitted ...



                          Some while later ...

                          The central backbone stringer has been cut through, as have the arches; the hatch comes free, as planned..!



                          I've put it to one side for now, as I've started the tailplane. Here's the first pieces...



                          ... and all the surround, complete...



                          There'll be a diagonal structure in the empty spaces, once the surrounds have been glued up.
                          A question, whilst I'm here: the plan calls for 1/8 x 1/4 hardwood pieces along the inside edge of each elevator...



                          Any idea as to their function..? Are they indispensable..? Thanks in advance for any light thrown upon this.

                          Comment


                            #14
                            The elevators also seem to be solid light balsa, in that case I think the harder wood would reinforce the elevators. In your case, since you are making the elevators as a structure it might not be a bad idea to reinforce the area where the piano wire will glue to the balsa, maybe with some epoxy in the under side.

                            Comment


                              #15
                              Good thinking; thanks for that..! I'll see what I can come up with. Cheers.

                              Comment

                              Working...
                              X