Geoff S

I had a minor accident and sprained my thumb badly back at the end of March and put my 3/4 done build on hold for a couple of weeks which extended until now I suppose I spent the summer flying but now the dark evenings are upon us I'm restarting. I'm about to fit the two tail servos. The question is 'Where?'. I'm intending to use either a 2200 or 2650 3S LiPo (I have a few for my other models) so I wonder whether I need as much forward as I can get, or would it be better to put them near the tail to get the CoG somewhere near. I'm sure there are so many finished now it's common knowledge where it's best to mount them thanks in anticipation Geoff

You speak a lot of truths, Nigel, but I can't help feeling that the repair of your lovely Tucano bears some resemblance to my grandad's hammer. It's 100 years old and has only had 3 new handles and 2 new heads I saw a YouTube video last week showing 'incidents' as a model club. Their usual response to crashes seemed to be setting fire to the airframe afterwards. Most of them appeared to be perfectly repairable. As a child of the austere 1940/50s and the son of a man who repaired everything I found that disappointing at best. Now I have received my decal set and covering film from Tim at Model markings and my thumb is gradually getting better I can get on with completing my own Tucano. It'll be in the old red/white training colours because that's the one I've always really liked. Attractive and visible in the air (I hope!). Not too much to do anyway. Right, off to test fly the Spit after a practise with my Riot. Geoff

Couldn't agree more, Phil. I'm sure I'll get a bigger kick out of flying the Tucano than the Spitfire but I couldn't resist it. It's just so pretty! Having said that, I've done 3 bigger ARTFs; a Maher's Thunderbird (Zenoah 26), a Great Plane's Super Stearman (Mackay 30cc) and Hanger 9 Thunderbolt (SC 90 FS). They all took me a long time to get in the air so were quite satisfying. Actually the Thunderbolt is yet to fly. I spent a long time sawing chunks out of the wings to fit flaps - scary! Geoff

There've been a few queries about fitting the wing servo on Phil's detachable wing. I've used my version of Phil's design and this is what mine looks like :   First, without the servo. A plywood tongue at the front and a single 5mm countersunk nylon bolt at the back screwing into a plate on the fuselage with a threaded insert (from ModelFixings - example shownin the photo)   Then the servo fitted in a partially recessed hole in the wing with hardwood stand-offs. The torque arms will be covered by thin ply (1mm) recessed into the balsa after the ailerons are covered and fitted permanently.   Not done much (ie nothing ) this week for a couple of reasons. First I tripped over and sprained my right thumb badly last Thursday 29th and it's amazing how hard it is to do woodwork without a useable thumb. My minor spinal injury makes me a bit unstable so I fall over quite often . Then second, a big parcel arrived from Hobby King on Wednesday morning and I couldn't resist putting it together despite the poorly hand. This what I ended up with. An 1100mm ws Mk24 Spitfire. Amazingly, it was cheaper than than the Tucano will be to build, cover and equip! Test flight tomorrow - I hope!   Geoff Edited By Geoff Sleath on 06/04/2013 22:21:00

Not sure about your specific receiver (most of my stuff is 35 Mhz but I've made a FrSky module for my Multiplex 3030 transmitter) but in a wooden fuselage it's fine to fit the antenna(e) inside it. If there are two antennae then they should be at right angles to each other to be most effective (eg one horizontal and one vertical). I find it works well to glue small pieces of plastic snake (I rarely use them as intended ) where you want the antennae to fit and slide them inside. It's better than taping the actual antenna because you can still remove the receiver easily if needed for maintenance or to use it in a different model. I'll be using a Frsky 4 channel receiver in mine which has only a single antenna. I'm not anticipating anyn problems in that area - unlike the rest Geof

I usually fit the hinges (of whatever type, except, of course tape or film) to the control surface first and then cover after pinning with cocktail sticks. I then fit to the wing or tail and cover the rest after pinning. Some people don't bother with pinning but I've seen control surfaces pulled off models when inspected before being allowed to fly at shows so I preer to be safe rather than sorry. It certainly doesn't do any harm and is quick and easy to do. Geoff

The source of all hinges and sundry aeromodelling goodies is SLEC. At least for me. Of course, other suppliers are available. http://www.slecuk.com/online-shop.html Geoff

Posted by Mike Hardy on 30/03/2013 14:03:03: Question - Ailerons how many hinges 3 or 4? Best place to mount on the centre line or upper surface? If upper surface I am not sure how to fit the hinges? Thanks guys for any tips. Mike.   3 hinges/aileron is more than enough. I've top hinged mine and used small pin hinges. You just have to cut the slots down in the right direction to fit them. Or as Nigel says   I did consider using both techniques but decided to use hinges. Geoff Edited By Geoff Sleath on 30/03/2013 14:14:22

Thanks both of you. Ian: I've had a look at mine and you're right. There is space above the aileron torque rods etc but it might restrict access to the wing bolt which is right at the T/E (see the photo on my build postings) Caveman: That's a neat, uncluttered arrangement that makes it worthwhile to go to the trouble of making a hatch. I'm also pleased to hear that CoG and battery position seems to work out well, too. I'll think a bit more. That could be a bad sign Geoff

Not much progress despite weather more conducive to building than flying. I've fitted the underwing sheet and glassed it with lightweight cloth and wing skinning epoxy. It needs a few more coats. I've epoxied and pinned all the hinges into the flying surfaces. I've fitted the aileron servo. The last job was slicing off the leading edge and glueing hardwood strips on to give it a bit of ding-proofing. It would have much easier if I'd done it before joining the wings. Next job is to fit the other 2 servos and install the push rods before enclosing the rear underside of the fuselage. Then all there is to do is finish carving the front top and bottom of the fuselage to shape. I intend to glass the underside of the fuselage as it'll be belly landing - lighter than an undercarriage, I guess. Then its covering and flying. Geoff

Just wondered where builders using a detachable wing are fitting the servos. I've installed my wing servo in the obvious place - just in front of the aileron torque arms wih short push rods. So now I'm wondering where the best place for the rudder and elevator servos is. Two possibilies are: first, more or less where the original design fits them behind F3 with an access hatch underneath. or, two, in front of the aileron servo position but I'm not sure what route the push rods would need to take to avoid clashes with the aileron push rods/torque arms/servo. There doesn't seem to be enough room above the aileron servo and below the canopy. I'm using Hitec HS82MG sevos for the aileron and elevator and an old Irvine Topaz 1000 (similar to SD200 I think) for the rudder. The Topaz is slightly bigger than the Hitecs but not much. Geoff   Edited By Geoff Sleath on 24/03/2013 22:03:13

I'm not sure that weight as such is a factor for flying in stronger winds (at least in a model not powered by gravity alone ). My heaviest model (a Maher's Thunderbird) weighs just shy of 7kg and still gets thrown about by turbulence becuase it has relatively low wing loading. I think it's the wing loading that is the real factor so adding weight in wind increases that. I can't say I've ever added ballast to a model that wan't necessary to get the CoG in the right place. I don't fly proper gliders. Oddly enough the model I'm happiest with in the wind has both low weight and low wing loading - my scatch-built Limbo Dancer. Perhaps it's because I'm not too worried about crashing it because I could build another quite quickly and cheaply or perhaps it's because it's so manoeuvrable. Wasn't it Colin Chapman (Lotus car designer) who said that the only vehicle where weight was an asset is a road roller? Geoff

Posted by Alan Randall on 21/03/2013 22:43:59: The owners of our site; Rolls Royce, forbid solo flying, and we have had to suspend at least one member doing it. It is forbidden on H&S grounds due to the remoteness of our flying areas, and the impact accidenst would have on the Company. If that's RR (Hucknall( then when I was a member there the reason given was that it was because of the full-size activities of Merlin Flying Club. I stopped flying there once I retired from the company because airfield access was difficult during the day and because I knew I'd be there alone often and be unable to fly. My current club recommends not flying alone but allows it. Just as well because I'm often there alone though I prefer it when there are a couple of others. I also fly alone in a local field with electric models. It's handy because it's just a 5 minute walk along a footpath with a model, my transmitter and 2 or 3 battery packs. I'm just extra careful when alone which is easy because there are no distractions. Geoff

Posted by Martin McIntosh on 22/03/2013 19:13:10: I find this fascinating that people are going into theoretical volume of air displaced etc. for such a small, simple model. All you need to do, since we now all know the motor size required, is to pick the largest diameter/lowest pitch recommended by the manufacturer and from the current draw figures add 50% for the ESC type. If it draws say 30A on this prop then get a 50A ESC and a 45-70C battery such as a Turnigy Nano 2200mA/hr. No need then to use two cheapo 30C batteries. Your model will be much lighter, you only need one pack at a time and it will fly very much better. See the power set up on` Martin`s retract version`. This has been flight tested and works. Edited By Martin McIntosh on 22/03/2013 19:16:46 Well those propeller volume calculations were ones I made about 10 years ago when there was very little information available for electric flight and I was trying to understand the marginal power available. I use them as a rough idea what propellers to use on both ic engines and electric motors if I have some slightly different ones in stock from the the one recommended. It works quite well. Lots of motors available don't really offer a suitable propeller to use. Sometimes they suggest a prop length but not its pitch which is a bit pointless. My usual method with an unknown motor it to under prop it and measure the current then go from there. The key is always to measure current before flying any power set up. Perhaps it's just my electronic design background over 50 years that encourages me to make measurements. If you're only drawing 30 amps from a 2200 3C pack then there's no real need for much more than a 25C discharge capability - even 20 C has a theoretical ability to source 44 amps. Of course you'll usually get better performance from a battery capable of delivering 45 or 70 times its capacity but its not always worth the extra cost. Geoff

Posted by Mike Hardy on 22/03/2013 15:32:10: Have completed joining fuselage sides but note how F2 has distorted at the bottom in spite of being reinforced with !/4" ply . Mike. I bored a very big hole in F2 (about 45mm diameter) which weakened it considerably but I fitted some 6x6 mm struts across the top and bottom to strengthen it. The end grain of even relatively soft balsa was sufficient to prevent the distortion you've experienced. Geoff

Not very exciting but I thought it may interest a few to see how I've attached the wing. This shows the attachment from above. Just a single 5mm x 25mm countersunk nylon bolt at the back and a 3mm ply plate at the front. The underside of the attached wing. I've inserted a 1.5mm ply plate into the balsa to take the load and a threaded insert (available from Model Fixings) for the bolt. The fuselage 3mm ply plate supported by a soft balsa 6x6 mm spar to give some glueing area. The top of the wing showing the support tongue (full width to provide a good location) and an example of the flanged threaded insert. I think they make a much neater job than the more common 'T' nuts. They are also useful in ARTF assembly because they can be fitted from the front of (say) a firewall when access to the back may be very restricted. I think a single bolt will be adequate. My Blizzard wing is held by single bolts front and rear and are quite highly stressed (the ply plate in the Tucano is as strong or stronger than a bolt) and my 84" 7kg Maher's Thunderbolt wings are held by 2 x 5mm nylon bolts and there's never been a problem in over 100 flights. Geoff

David That all looks very scientific and interesting never the less. I use a much simpler estimate to judge the load different propellers impost on a motor and probably even more 'clapometer' than yours. I just calculate the cylindrical volume of the propellers assuming 100% efficiency. ie the area described by the propeller's length and its height (the pitch). Hence an 11 x 7 will move 665 cu ins of air/rev and a 12 x 6 678 cu ins. It seems to be roughly reasonable if I measure current draw on load. Now how that relates to thrust either statically on the ground or dynamically in the air, I don't know, but I tend to go for lower pitch propellers in smaller or slower models because I think it helps slowing down and the lower pitch speed gives nearer to scale air speed. I'm no expert, of course. Geoff

Posted by david fillingham 1 on 21/03/2013 12:40:04: I flew this with a 3542 / 1250 Kva motor + 10 x 7 prop and latterly with 3542 / 1000 KVa + 11 x 7 prop and the vertical performance is incredible. Regards david That's good to know, David, because your second motor is exactly similar to the one I've chosen. I have been intending to use a 12x6 prop but that shouldn't be too different from your 11x7 as regards current draw and performance. I agree about the variability of the CNC packs. I've had no trouble with my fuselage sides bending to conform with the formers. What servos are people using? I have a couple of new Hitec HS 82MG in stock. They were intended for another project so I'll use them for ailerons and elevator. I also have a pair of Tpoaz 1000s which I think are the same as SD200, which must have come from a dead model; I think I'll use one of them for the rudder. Geoff

Nigel Although mine will be belly landed, it will be launched with a dolly because I have great difficulties hand launching due to an injury. So, hopefully, it won't suffer the mid-fuselage hand launching blues like yours Extra weight isn't necessarily required to fly in strong winds. The models I reach for when it's windy are my scratch-built Limbo Dancer and my foamie Riot, neither of which are heavy (approx 1 or 2 kg). I haven't tried the Limbo in strong winds since I electrified it but I don't anticipate its being any different than formerly. I pleased to read that the Tucano is likely to join them. btw my model is also built from the CNC pack. They're obviously not all the same. Geoff

Mike I also used a SLEC fuselage jig and didn't find too much difficulty though I didn't have any ply doublers in place. I do have some of the small sash-type clamps widely sold at model shows on the tool stands. I have retro-fitted doublers but mine are 0.8mm. Nigel's 1.5mm seem pretty big to me but who am I to criticise the designer? I admire his patience as well as his finger grip if he's happy to hold all in place as the epoxy sets. I left mine over-night but I do use Grip 1 hour epoxy which takes quite a long time to cure. I didn't fit F1a until after I'd done all the other formers as well as joined the sides and rudder post. F1 a needs to be trimmed at the top to suit the curve when you pull in the top part of the sides to meet the former curve and that's much easier to do later. Geoff

Posted by chris edwards 3 on 19/03/2013 17:21:08: carn't wait till i can drive, then no more towing a heavy trailar up to the club with my bike. Good for you. I used to do a great deal of cycling and still ride up to the club through the lanes occasionally but without a model. There are several quite major climbs (and descents) for me so taking a model that way would be something of a challenge. Derbyshire isn't all that flat My wife's fitter than I am these days. She did about 80 miles last Saturday, not bad for 72 Geoff

Well I'm in the oldest group but I didn't take up the hobby until I was 55 when I took early retirement (it was supposed to be semi-retirement but no-one wanted a 55 year old electronics engineer). I started RC modelling after an accident stopped me sailing completely and made serious long-distance cycling too painful. Aeromodelling is definitely a second choice for me but still quite a good one. Geoff

My build is at the stage where lots of time seems to result in very little to show for the effort. Before fitting the top and bottom of the front part of the fuselage it's better if the wing and cockpit are in place so I've been making the cockpit and joining the wing using Phil Winks' idea for it to be detachable. I felt the rise of the bottom of the cockpit needed to be a bit more than on the drawing. I discarded the idea of adding to the fuselage side and went for the detachable cockpit side instead. Here's my cockpit base:   I made some 1.5mm plywood sides and glued them to the bottom so that they matched the fuselage width. Then I added balsa strips inside just a bit wider than the canopy is thick to form a slot to hold it. The only problem with this is that it reduces the space available for the Vortex cockpit interior so they needed to be trimmed as did the pilot's shoulders but the didn't complain and I hope it won't impair their flying skills! I'm not a brilliant pilot painter but they don't look too bad from a few feet (like 100 ) I'm not too sure but I think they may be a female crew - hard to tell. The transparent cover fits quite well without the need to glue so once it is glued it should be secure.   Still needs a little adjustment to make it fit the fuselage accurately but a Geoff bodge will sort that out. I intend to fix it with a wide plywood tongue at the front and magnets at the back. The plywood sides will hopefully make it less likely to be damaged in handling when changing batteries.   Despite lots of trial fits of the wing components, once the glue (Titebond aliphatic) was applied it was much more difficult - the braces are a tight fit in their grooves. I made the mistake of trying to glue the dihedral braces, both wings and the three centre section all in one go. I succeeded but it was touch and go because the glue was going off faster than I thought it would. Better to fit the braces into one side first, then add the main centre section piece between the braces and the other wing and leave the front and back centre pieces until last. Here's the wing neatly fitted to the fuselage and it checks well for position.     The two short pieces at the inboard trailing edge are very vulnerable to damage; because of that and because I'll be belly landing I'll be adding an epoxy glass cloth layer over the bottom sheet. Mounting will be 2 4mm nylon bolts. One at the front and one at the back. The square centre section in the fuselage will keep the wing in place. Geoff Edited By Geoff Sleath on 16/03/2013 20:08:28

I'm sure XT60 wouldl be more than adequate. Most of the time you'll be flying on much less than full throttle. I've standardised on 4mm bullet connectors (Batt pos male, batt neg female) for all my bigger packs and 2mm for smaller packs drawing fewer than about 15 amps. That's what HobbyKing (or is it Giant Shark?) use on their 4S packs, unfortunately they adopt the opposite polarity from me so I still have to cut them off and solder my own on. Geoff

Posted by Mike Hardy on 13/03/2013 10:12:25: I plan to use the Turnigy SK3 3542 1250kV Motor with a 9 X 6 prop and 4S Li-Po, where can I find the performance curves for this motor? Or does anybody on here know what to expect in peak current/power. What spec ESC should be chosen? Mike. I think if you're planning to use a 4S pack you should use a motor with a lower KV - say 1000 rpm/volt or even 850. The only model I fly with a 4S pack at the moment is my recently converted Limbo Dancer which has an XYH35-48 790kv motor and draws 52 amps on a 13x6.5 prop and 35 amps on a 12x5. A 9x6 prop shifts (theoretically if it were 100% efficient) 381 cu ins of air/rev and a 12x5, 565 cu ins and you are going to be driving yours (again theoretically) half as fast again so I would hazard a guess at about 40 amps, perhaps less. That's 40 x 14 = 560 watts. I intend to use an XYH35-42 1000 on my Tucano on 3S 2200 or 2650 Ma/h depending on CoG with a 12x6 folding prop initially. I have a Black Magic 50 amp esc (The Limbo uses a 60 amp Black Magic) Trying to get motor information is difficult but this may be of use. http://en.xingyaohua.com/html/class/213.html Geoff