robk

Hi Ron I have just sorted it out - found the answer on another thread. I had reversed the aileron in inputs. I changed that back to positive and reversed it in outputs and all was well. No doubt you were going to advise the same solution.

I have another problem. I have set up one of my planes on the tx and reversed the aileron channel which works fine however the trim tab for that channel still goes in the old (now reverse) direction. I can't seem to find out how to reverse the trim tab as well? I actually crashed a plane as I was adding in more trim in the direction I thought it needed when actually was adding it in the reverse direction.

bambinarob.mov

I went to the field two days in a row (what a relief!) and maidened the Bambina. My pal did a hand launch underarm as there isn't much to get your hands on holding it from the bottom. Both days were relatively calm with winds c.5-6kn. First flight was a bit hairy trying to adjust the trim on a brand new transmitter (first time I have used my Radiomaster TX16S). Also, the controls were having too much effect and I reckoned it could do with a little more weight in the nose. Second flight after reducing aileron input and putting 5gm in the battery compartment went worse and flying away from me it got too slow in a turn and spun in from about 20 feet up. Very little to fix though as its just a light plane and I obviously put an ample sufficiency of glue in there! Next day try again, now with 10gm of weight near the front and more expo on the ailerons and elevator. Also with a note to self - keep the speed up. RESULT! Two good long flights and I was now able to tweak the trim as it was much closer to a balanced airframe. It flies very well indeed for such a small plane. Its fast, but not scarily fast. Its not for a beginner though. I did a few loops and rolls as confidence grew. It needs to stay quite close as its only tiny. Landing is easy - power off and glide in. My fettling advice is: I think the CoG should be a little in front of the location on the plan (at least to start); you need to fly it fast and don't dawdle in the turns; throws as recommended are about right (I have taken a couple of mm off the ailerons but mine are bigger than the plan) but you need plenty of expo in there if you want smooth manoeuvres. Here are few phone pictures and a short video from the first flight after I made the changes. It was smoother still in the last flight of the day. My only modification will be to get some better carbon fibre Graupner CAM prop blades to up the thrust a bit as I was flying on 3/4 throttle most of the time and launching on full.

So here it is finished. Solartrim was used for the black bits on the wings and the dayglo piece on the underneath. The prop is a refurb of the one that was on the original Mk 1 Kinetic that was the donor for the motor etc. I ordered three different prop sets from HK and none of them fitted - in some cases the the diameter of the spinner was just plan wrong. However, I managed to remove the propellor blades from one and fit them to the old Kinetic spinner so job done. Ive set the throws up as per the suggestion in magazine article and the CoG came out bang on with no lead added - that's a first! When the shops reopen I will buy some Humbrol pots to colour in the control arms so they are less obvious. Weather is looking good this week and our field opened today so fingers crossed it will get a first flight over the next day or two. I'm nervous already.

Last job was installing the radio gear and motive power - its pretty cramped in there but everything fitted in. Bear in mind my battery is 3S 850mAh so more than double the power of the proposed design.

No. Before I glued the bottom down I made sure I could install it by pushing it through from my long top hatch. By the way, my motor was bigger than the one used in the plan as well, I just made the fuselage a bit wider.

Onto the covering. I dithered about this for a while - whether to just paint the fuselage or cover it? In the end I went for a bit of both to meet the colour scheme I have planned. Red HK covering film with some paint sprayed on the top part of the fuselage. I put some Balsaloc on the plywood bits and fiddly areas first and the covering went on with bit of fiddling under the tailplane were the control snakes emerge. My replacement folding prop just arrived in the post so I will set that up next.

The motor and ESC need some ventilation so I have cut two holes on the sides of the fuselage (as it has no undercarriage I didn't want one underneath at the front where it would pick up dirt). There is a hole at the back equal in size to these two for the air to exit.

Here is how I made my hatch. I glued a pin in the hatch cover and then put some graphite on the end of it and offered it up to the fuselage former to make a mark which I then drilled. A SLEC hatch catch is glued with epoxy into the front of the cover and I repeated the same process.

Hi Pat Yes this is a poor plan and no not all plans are like this. This is my first RCME free plan build but I think it depends on who has drawn it. Others I have used have been very good with no errors (except my own when building!). The Tony Nijhuis one you built was also a free plan and I am assuming that was good as he is a well-respected designer. A plan view would definitely have been useful. Regarding W1 - I did just have one of these in my build as I made the wing in one piece flat on the board (its so small) and then cut trailing and leading edge and spars on one side of W1. I then rejoined the two wings with the appropriate dihedral and a 3mm ply central brace cut into the top of W! in front of the spar up to the second W2 on each side. You are right about the fuselage former having too big a gap to receive W1 correctly. I built the wing and finished it and then offered it up to the semi-built fuselage and glued in a new piece of ply (not light ply) behind F6. I have previously said that the projection on W1 is too short and made a second one with a longer projection.

What a great job, Phil. Those transfers make a lot of difference. I put some on my build - not as clear as yours I am afraid, but from a few metres away they looked the part. Of course when the plane is in the air you dont see them but you know they are there... right?

This is another modification from the plan. I didn't fancy the pop bottle canopy so have built a balsa 'racing canopy'. I quite like the look of this - others might not. It also allows me to have my long top hatch. If you look back at my first photo of the plan I had already drawn this in before I started construction. Next is to let the filler dry completely, followed by a very light sand and then a coat of sanding sealer. I still haven't decided on a colour scheme.

The rear fuselage floor is just a 3mm balsa plank with an added 'tail-skid' balsa block. I will toughen that up with a coat of varnish.

Hi Pat - I have ordered a replacement 35mm diameter spinner and folding prop from HK but might just use the Kinetic one which is also 35m. I have sized the fuselage for this. Made a bit more progress on the fuselage. I planked the top of the rear fuselage with 3mm square balsa strips using cyano so they would hold in place without a load of pins, then filled with polyfilla advanced lightweight filler. This sets quickly but is fairly fragile. After sanding I fitted the fin strake.

I put it together and it is a pretty plane - if it looks right....

Here is the wing servo mounting and control run.

Thanks Patrick - I want to make the Nijhuis Mig 15 at some stage - glad you thought they were a quick build. Anyway, Ive been putting in the control runs over the last couple of days. I wanted something light but also something I just had in the bits drawer. In the fuselage I have used a couple of short plastic snakes, leftovers from cutting down longer ones on another job. I fixed the wire ends using cyano and heat shrink. Another problem with the plan appeared whilst doing this. The rudder does not protrude below the elevator far enough to allow both to operate without fouling each other. I therefore cut the horizontal section out of the rudder and replaced it with with a slightly deeper piece (twice as wide as the one on the plan). The rudder now operates freely. I will put a tail skid in so it doesn't foul the ground on landing.

I have begun work on the fuselage again too by planking in the front end, 6mm thick balsa on top and at the front on bottom and then 3mm elsewhere. The original design had no hatch at all, assuming you put the battery in by removing the wing. That is awkward in my view, so I have included a hatch - and its a big one so I can place the battery wherever I like from the CG to quite a way forward. Because I have a heavier motor and battery in mine I am not sure where the battery is going to need to be placed. The hactch also gives me access to the ESC and means I can install the motor after sanding and covering (I did a dry run before gluing in the planking). I need to put in some ventilation holes in the fuselage, probably the sides so they don't fill up with dirt when it lands.

So I've been carrying on with sheeting the wing, top and bottom on the centre section and along the leading edge. The green string is there to pull my servo wires through. A couple of 10mm wide scrap balsa blocks form the wing tips. Mine are slightly different to the plan in that instead of reducing them in width towards the trailing edge I have left them square so they can form a bit of protection for the aileron.

I am placing the servo arms on the top surface of the wing because I am not having wheels - saves the control rods etc. being ripped off. You see the plane mostly from the underneath anyway when its in the air! I was going to wrap shrink wrap around them and epoxy them to a beefed-up wing rib but I didn't have the right size shrink wrap, so instead I put in two 4mm spruce bearers. The balsa around the servo is to provide somewhere to fix my covering film to. It will be tidied up a bit once I sand the wing.

Cut and assembled the tail. Very simple sheet but adequate for the job. Something else not on the plan is how you join the two parts of the elevator together. I have used a piece of wire bent to shape then inserted into pre-drilled holes and a groove in the rear of the tailplane and fixed with epoxy.

Started sheeting the centre and front of the wing. I have also put in a solid balsa section towards the rear of the wing ribs where the wing bolt goes otherwise this area will be crushed. This is not shown on the plan as the bolt is shown going through the very narrow trailing edge - not strong enough in my opinion so I moved it a bit further forward.

HI Patrick - yes the plan has quite a few differences. I am going to sheet top and bottom because I am not having any u/c. The grass on our field will be too long. The rib section as drawn on the plan does not allow for any sheeting at all! I dont know about the sarik kit, but you might need to narrow the rib section in front of the spar to allow for the sheeting. Also, I made the ply rib for the centre of the wing, tried it in place and found that the projection that fits into the fuselage former was too short. I had to make a new rib with a longer projection. Regarding the wing seating, I have assembled the basic fuselage structure but I am waiting until I build the wing to try it in place in order to get a perfect fit.

Here is the wing under construction. A bit of a fiddle to build because of the symmetrical wing ribs. I pinned the bottom wing spar down then glued the ribs in place, then glued the top wing spar in place and pinned the trailing and leading edge to the board with a 6mm spacer underneath. Then I went along the wing starting at the trailing edge gluing each rib in place with cyan and then did the same at the front. I have put fillets at the trailing edge because otherwise these seemed weak to me. I have also put a vertical shear web in for the centre section. Regarding the dihedral - I think it needs it as the wing does not taper and there is no sweepback. I chose to build the entire wing in one piece flat on the board. I will break it in the centre when I lift it and rejoin it with the dihedral. I am also inserting a ply brace across the centre break (nothing like this is mentioned on the plan).