Peter Ford

THE PARTS SUPPLIED Well, this is what you start with. You will notice that all the wing ribs have 'tabs' to allow the wing to be assembled flat on the building board. The tail parts consist of the outlines cut out in thin ply, to which one builds a balsa frame on either side. This makes a very sturdy unit. The fuselage comprises a front assembly, which can be assembled dry to check the parts fit. The way it all fits together means you can virtually hold it in your hands, with no glue and it just sort of 'hangs together. There are engine support bearers running through the front structure. I have cut mine off in front of the firewall, as this model will be electric. I will make a removeable lipo access hatch. The Lipo's will sit on a ply plate glued to the remaining part of the engine bearer, secured with velcro straps

That should read slightly BIG My return to modelling a couple of years ago was inspired by the prospect of a new angle of electric flight After having knocked up a few ARF's to get back 'in the groove' and to assimilate all the electric stuff, I began to look around for something to actually build - you know, wood, glue, tons of dust etc etc. There are not many kits about. I trawled deeper into the Google searches, and came across a man who laser cuts sort of semi - kits Now this is NOT a complete kit. There are very basic instructions, and so a degree of experience would be advisable. However, all the ribs, fuselage bulkheads are laser cut,together with the six foot mainspars, Cowl, and canopy are also available. The wing and tail tube joiners are also supplied So all I need is there. Falcon Aviation is a small concern dedicated to builders who still want to do it. Richard is the man who answers the phone, cuts the parts, posts them, sweeps the floor, and runs the complaints dept This is the prototype of the 1/3rd scale Fournier At Falcon HQ I talked at length with Richard about his work and the models he produces . He spends every night on the computer producing CAD drawings for printing and for the laser cutter. I took delivery of the Fournier bits. For @ £250.00 you get the main bits including all the ply cut parts, The six foot spruce stringers, the alloy wing and tail joiners, including the phenolic resin tubes they slide into, and a cowl & canopy. The rolled plans would just about paper my downstairs loo!! I have also bought @ £75.00 of mostly 3/32 balsa, some block, strip and a giant bottle of aliphatic glue.

Not quite sure what you mean by disabling the ESC. Perhaps you are suggesting grounding the signal line from the reciever? The 'elf & safety' argument is that an 'Air Gap' be required in the power supply wiring to be absolutely certain that no catastrophic failure in the ESC Thyristor system can inadvertantly pass power to the motor. I appreciate that even a big hefty switch can fail although much more unlikely than any semiconductor circuit.

A long time ago I used to work as head of design for a company  that made heavy industrial equipment- sort of giant microwaves. Previously, switching was done with huge contactors (very big relays, if you like)  My Boss wanted the switching replaced with semiconductor switching- similar to an ESC but good for 12000watts!  When the service manager heard about it he nearly callaed a strike. He wouldnt allow any engineers near the machines unless they were fitted with a conventional isolator switch. So you see its really about 'elf & safety'.   When large electric models are appearing at model shows, if I were flightline manager, I would want visible proof that the electric stuff was safe untill immediately before 'power up'.  Something similar to the safety tags on ejector seats which have a large red flag or streamer attached to a pin thru the gun 'sear'. Every single mechanic who works on a modern fighter jet has to check the seat is safe, before entering the cockpit. If you think this sounds OTT & dramatic, I'll attach a photo of the scar on my lower forearm caused by a stroppy 35cc petrol engine on my Spinks Acromaster. Thats 13 Stiches,and the blade cut the venous artery. The only other man in sight was a spectator, who, as it happend, was an off duty paramedic-amazing innit.  Always Broke is right, Timbo, Should be one safe rule, in watever form that might be, for everyone       

. If the model is an IC conversion, its not always easy to connect / disconnect the battery plug. I have an electric Topgun Spitfire with 2 5S packs (in series!) I have to install these lipos and then bolt the wing on. With a 'live motor' no way! In this case a quick trip to the local motor spares shop and I had one of these . Its used as an electrics safety isolatorby the racing boys Looks a bit big, right.. Well for a start, you can cut the 'key' down to a stub, cut a slot and operate it with a screwdriver. You can also remove two of the nuts, at the bottom. Dont forget to buy two suitable ring tags for your wire size. This switch handles 100AMPS at 12 Volts. I am using it on a 10 S setup with a 2Kilowatt electric motor no problems. The 12 volt rating is a bit conservative IMHO. No connection 'sparks' either For smaller models I use a Deans shorting plug to make with a socket embedded in the fuselage You can see the Deans socket here on my electrified Vmar Bulldog. I reinforced it with a ply backplate My biggest fear is catching my TX neck strap on the throttle stick. Nick your rubber band idea is a goodun.

Go buy a Cellmeter from hobby City. They're not exactly cheap, but I wouldn't be without mine ever again. And judging by the rave reports by others, neither would they. It has a ' Fuel guage' bargraph which shows what is left in the battery. Gives various readouts to display each individual cell voltage. Also shows the overall pack balance and whether your balance charger is doing its job. This is achieved safely and easily by connecting its multi pin connector to the balance plug. The CELLMETER gets its operating supply from the Lipo under test. Handles up to 8S packs. Also gives a lot of other stuff to do with prop sizes etc. It is possible to get a 'sort of ' Chinglish translation via Google. For further info look here. http://www.hobbycity.com/hobbycity/store/uh_viewItem.asp?idProduct=6232&Product_Name=Cellmeter_8_for_Lithium_Polymer_Packs Its a helluva useful thing for £50.00

Re The RED wire questions This depends which type of ESC you have. If the ESC has BEC built-in, then removing the red wire from one ESC ensures that the remaining ESC is powering up the Reciever-if you intend to go that route. Not the best Idea I think. I use a separate UBEC. If you have ESC's with OPTO isolation (and by definition NO BEC), then removing the red wire can cause problems for the ESC. The reason for this is on certain makes of ESC the opto- coupled circuit gets irs power from the Reciever supply. If you are flying a twin then these are the facts, speaking from practical experience on my B25. 1) Use one common battery supply. 2) Always use TWO ESC's 3) Consider disabling the low voltage cut-offs on the ESC's and using a separate Low voltage monitor  device. Graupner make the best one IMHO. Its a measly Twenty Quid.  If you disregard this advice, then sooner rather than later, one motor is going to quit before the other, on a low voltage detect . Now tell me it aint so

I prefer a separate Ubec plus a separate small Lipo. Here's why: 1) Charging a small(ish) Lipo is no big deal. Its quick, and it is always ready for use 2) You can check the radio system without the motor being live 3) I lost my CAP 232 when a faulty connection on the motor battery WITHOUT separate UBEC battery caused everything to die. 4) I also have a special 2600 ma Lipo in my TX (Futaba 7C 2.4ghz) 5) I do not have any Nicad or NiMh batteries in use these days

A Cautionary Tale An old acquaintance of mine who lives in the next town, Mick Reeves, once said: If your maiden flight is a success, then no matter how fine a day it may be, take it home there & then- in one piece- and go over everything again, screws, links, solder joints etc. With his words ringing in my ears, I discovered the wing dowels were not glued in !! . It will be a week or two of checking over I think

B25 video now on Google as you can see the grass is a bit 'ratty' The battery packs lie directly acros the C/G Google Link: link Conclusions It has been an interesting project. Electric flight has, after many years of flying glow & petrol re -awakened my interest in model flying . It is not without its own problems. I have been in electronics all my life.and there are still always new thing to learn. My 88 year old father, who was a full size glider pilot in his younger days, has a keen interest in electric R/C flight. His eyesight is not sharp enough for model flying. But he still builds them, and I get to do the flying. 50 years ago he was teaching me! An Old Bold Pilot with his Tiger Moth

B25 MAIDEN FLIGHT!! At 1430 hours today I roareddown the strip and UP UP & AWAAAAAAAY. The book said use 1/2 flap on rough grass. Well maybe, if you have marginal power. I had loads it seemed, because it reared up of the ground a bit quick. I hastily got it sorted, wheels up, flap up, and into the first turn. A wide and quite steep turn, back up the top of the field and in for a low pass. Wow that looks the biz     . I had set the timer for 4 minutes, so I started throttling back for a trial approach & overshoot on 1/2 flap. That big wing certainly has some lift. The plane just floated on down the runway at @ 50 feet.  Now the timer is bleeping in my pocket, so I had better get this baby in circuit for landing. Wheels down, half flap and a nice long straight in approach. It wasn't sinking very much. I should click in some down trim next time. The first wheel touch was too fast and she bounced about 10 feet . Keep cooool and level and let the speed die a bit more. Now the second landing was better Model was checked over. I found a tyre half off the rim, on the port main, and the nose leg retract block needed squeezing back as it had spread a bit. The speed controllers were cold, and the batteries barely warm. The flying performance of this plane in the air is very smooth- thats what you get with large models. They don't however, like rough landings. Things get bent all too easily. The ground clearance with 13 inch props on grass means I have green stains up the flaps! The field I fly on is used for Sunday Morning car boot . Its big, but a bit 'Agricultural'  My Neibour, Andy, has the stills and video clips. Hope to get these posted in the next day or so. It would seem that 36 volts( 8 S ) @ 5000ma is not going to get me very long flight  times. I may have to consider more efficient motors. There is not much more room in the 'bomb bay' for larger capacity batteries. I am going to have a think about the new Turnigy SK Aerodrive range. I have one in a CAP 232 which is a very smooth performer. Anyway its a RESULT Now for a few Fosters!  

When we refer to the C rating of a battery this is NOT capacity. A battery's capacity is mearured as its nominal Ampere/hour rating. In our models its is ofren expressed as milliamperes. This is more properly milliamps/hour The 'C' rating of a battery is is the multiplier over the nominal rating, at which current may safely be drawn without detriment to the battery. Example 1:    a 5000ma battery with a 20 C genuine raing can deliver 100 AMPS (5 X 20) Example 2:   a 2500ma battery with a 25C genuine rating can deliver 62 AMPS 2.5 X25)    Where the demands on the battery are greater than its nominal '1 C' rating then you will get less than the (theoretical) ! hour. AT 2C it will be !/2 an hour. At 4C it will be 1/4 hour.  You cant get something for nothing. The blessing is that with our very efficient electric motors combined with light batteries with high energy density, we can have electric flight times of 5-10 minutes or longer.