John Olsen 1

Hi Adrian, Your ignition ideally wants to be on a separate battery with the optical isolator to switch it since you really don't want ignition pulses getting into the receiver and servo wiring. So that is likely to mean that you need two batteries for the receiver and servo redundancy and one more for the ignition. The ignition stuff should all be kept as close to the engine and as far away from the rest of the gear as space permits, with only the opticaly isolated switch connecting them. I agree with Herri, you probably don't want the receiver and servos running off the same supply as the ignition. Now, if you are using two batteries for the receiver and servos, the question becomes how do you link them together? If you just parallel them, then if one battery goes faulty, the other will try to charge it up and you will eventually run out of power. If the faulty battery has developed an internal short in one cell this could happen quite quickly. It is better if you can link the batteries with a pair of diodes. That way, the two batteries are independent and whichever has the highest voltage will supply the load. However the diodes will drop the voltage a little, typically about 0.6V. That may be acceptable, especially if you are running off 6V (5cell) NimH batteries) Incidently with the right sort of charger you can put a charge into NimH cells quite quickly. John

Tim, it sounds like you will be ready for another project soon. What about a Supermarine Quadraplane to follow up? **LINK** Looks like fairly complex rigging, and it is a twin too, just to add to the fun. John

Since the ailerons are at the outer end of the wings, could the effect of washout be acheived by setting both ailerons slightly in the up direction when at neutral? This would be simpler than building it in to the whole wing, and would also be adjustable. Eg if the stall proved very benign, try reducing a little while if it drops a wing too readily try increasing. (I am assuming stall tests at altitude of course!) John

Is this perhaps getting into the size range where it would be desirable to have more than one battery? Of course then there needs to be some sort of powerbox to allow linking them without a faulty one taking the other out. John

Well, anybody who is a flyer should know that they can get about half a dozen jets for that price, so it is evidently aimed at the ignorant. It would go down well at any gathering of Terry Pratchett fans, provided you managed not to actually kill any of them. So how about a free plan version for the magazine, maybe a bit smaller and ducted fan as suggested above? John

Note that the steam boat ban was actually back in 2011. There was something about it in the Model Engineer at the time. I think really it had more to do with infighting in the club than any actual hazard. Actually having had some experience of both, I would say that the LiPo batteries in the electric boats are a bigger hazard than the type of small boiler used in this type of boat. Small copper boilers fired with burners of limited power are actually pretty well inherently safe. What this means is that if you lock down the safety valve and turn off the steam to the engine, the burner cannot build up enough pressure to cause the boiler to fail. Apart from that, the energy stored in a boiler is a function of the volume, and the amount stored in a typical small model boat boiler is not a great cause for concern. Most regulations have a minimum size below which they don't care what you do...Here in NZ anything below a cubic foot and 100 psi is able to be certified by the model engineering societies, and if I recall correctly, below about a litre or so there is no regulation at all. How often do people get their Mamod and Wilesco boilers tested anyway? But people tend to fear unfamiliar things and what they don't understand. John

What sort of ignition is it? For example, is it a built in magneto (like most lawnmowers), a battery and coil setup, or a CDI unit? If it is a magneto, most of the wiring will be enclosed and the only likely problem is radiation from the plug lead and plug. A shielded lead would help there, and the other thing to do is keep the receiver aerial and all other wiring as far as possible from the engine. In a boat you might also be able to arrange some shielding between the engine and the radio gear. It can be pretty light, even tinfoil glued to a balsa bulkhead will help. If it is battery and coil, or CDI with a battery (like my Powerhouse model) then one important thing is to keep the ignition supply on its own battery, eg don't use the same supply for the radio and the ignition. My setup actually has an optically isolated switch that is operated by the radio, so the ignition can be turned off from the radio but without providing a path for noise to travel from the ignition to the radio gear. Sometimes interference is not through noise signals getting into the receiver as such but due to voltages being induced in leads like the servos. This is where the ferrite beads can help. Another thing that can help is putting a twist in all leads, eg battery and servo leads. (Telephone cables use twisted pairs to help reduce the crosstalk between pairs. At an extreme you could put a braided screen over all leads (except the antennae) and connect it all to a common point. The other thing that should not be too hard to do with a boat is to do a decent amount of testing, particularly at long range, before the maiden voyage. Don't just rely on a range test mode on the transmitter, actually check that the controls operate reliably at the longest distance you are likely to want, with the engine running. John

Balsa USA also do a Taube, a bit smaller than the Flair one, and I think not as nice although I have never seen the Flair one other than pictures. The BUSA one flies very nicely on rudder, elevator, and throttle and looks the part in the air. You can get a nice Dutch roll going in a free flight model if you overdo the dihedral, so it doesn't always have to be pilot induced. John

I think John Stones is probably right, give the engine a few more hours and you will find it frees up a bit. You will eventually of course want more power, isn't that always the way! Also what the others say about using a bit of some sort of detergent is also good. Anyway, nice that you seem to have sorted out the receiver and servo side of things OK. John

Well, there is another thread here about my recently completed repair to my Powerhouse model, that took over 40 years. Actually I think it might have taken 47 but I am not quite sure which year I crashed it. Anyway, congratulations on getting it in the air at last. Have you got a full range receiver in there? My son and I have found out the hard way that there is a difference Don't throw away the seized engine, it might just be gummed up with castor oil residues. It may live to fly again. John

It does sound like you may be exceeding the current that the built in BEC (Battery Eliminator Circuit) in the ESC can provide. That would mean that the voltage would drop, causing the receiver to drop out and misbehave. You can get a separate BEC circuit, they come in a variety of current ratings and often can be set for either 5V or 6 Volts. They tend to be cheaper than ESCs. Otherwise, you could run the receiver and servos from a NiMH pack, these are usually 4 cell for about 5 Volts or five cells for about 6 Volts. That eliminates the need for a separate regulator (which is what the BEC is) to give the right voltage for the receiver and servos. If you have a voltmeter available you could measure the voltage from the ESC to the receiver and try the setup again. If the voltage drops when you connect the servos it confirms that they are taking too much current for that supply. The receiver itself can probably drive the bigger servos OK. The extra current they take only passes through tracks on the PC board, so unless they were taking enormous current there should be no problem. However, one thing to watch is what range the receiver and transmitter are capable of. A plane that only needs mini servos is probably not intended to be flown very far away. So do check that the setup will work to the sort of range you are likely to need. If there is no range test mode, just get a mate to walk away from you somewhere convenient where you can see each other, one with the RX, battery, and servos and the other with the TX. If the guy with the TX waggles the sticks from time to time, and the guy with the RX waves back to say they worked, you can keep walking apart until either it stops working or you can't see each other anymore. So long as it works to a range where the new plane would be too hard to see you would be OK. John

Maybe I should clarify...it is the models first flight in over forty years, not mine. Can I claim some sort of record for longest repair job? It sat for a while, then I started rebuilding the wings about 25 years back, then it sat again and went into storage when we had two years on contract in Germany. I started on it again when my son got me back into models by getting himself a foamy glider. I learned to fly with that after him, then have progressed onto a range of things, including a foamy Stinson, an electrified Stick, a ducted fan Mig and a Ember indoor flyer. It is probably too easy to fly to make a good trainer, apart from the ground handling. It flies slowly so there is plenty of time to make up your mind what to do, and it is big enough to not go out of sight in a hurry. You could hand the transmitter over to a complete novice to let them have a try with no worries. Now speaking of cycling to the flying field...when I first built it, I used to take it to the flying field fully assembled and held under one arm while I rode my bicycle a couple of miles to get there. A box on the carrier held the fuel and starting battery for the Ohlsson and Rice engine. You wouldn' have wanted to hold the model like that and ride the bike in any sort of wind, but then, if there was any sort of wind you weren't going to be flying this anyway. At the time, the Tomboy was quite a popular design in our club. We noticed that in fact the designs are not dissimilar, with even the same number of ribs in the wing. But being much bigger, the Powerhouse was a lot easier to trim and fly and it outlasted quite a few of the Tomboys. The Masterton club at that time flew on Hood Aerodrome, a grassed strip that had been used by Mustangs during the war. We were allowed to use it and had a mown circle for control line and a strip for radio control, of which there might have been one or two in the club. None of us boys could afford any. I don't know if the authorities had thought much about the implications of free flight on the strip. It was fairly quiet mostly, one passenger flight per day, and a few top dressing aircraft, but they usually only left in the morning and came back in the evening. Anyway, one day I was there on my own. The Powerhouse did its usual long run off the mown strip, then into its big lazy circles for the climb. A couple of minutes of engine run, maybe 200 feet up, and the engine cuts and she goes into the glide. Hmm, it is still climbing. We've caught a thermal. Naturally I followed it as it drifted downwind...across the main runway. When I'm in the middle of the main runway, trotting briskly, I look both ways. Oops, there is a DC3 down there to the south! Probably still quite a few miles out, but lined up for the runway. So I kept on running. I don't know if he saw me, but anyway I was well clear and actually over the fence by the time he did land. We never got a complaint about it. The Powerhouse drifted on and made a water landing on the Waingawa river just beyond the aerodrome boundary. I didn't actually see the landing, it flew behind some willow trees while only a few feet up and when I got past the trees it had drifted into the willows on the far side, floating nicely. No harm done, but I did fit a dethermaliser after that. On Sunday when I flew the Powerhouse, I did three flights with it...with the first two I got the club instructor to take off while he sorted out the trims. I did the second landing and the entire third flight. In between I flew my electric Stick, which could hardly be a greater contrast in style. The Stick is the 40 size Great Planes one, somewhat overpowered with a 60 size plant in it. It will go vertical no problem, and of course can perform a good range of aerobatic manouevres. So...from the sublime to the rediculous! i had actually thought that the Powerhouse might be harder to land than it is. It is naturally enough a pretty floaty sort of design, but it turns out that you can bring it in to land with a bit of power on still and there is no problem. When I say a bit...normal crusing round on a circuit only needs about one third throttle. I guess it helps that the spark ignition allows a pretty good slow idle. It is very quiet. When I went to idle in the air at one stage, some of the guys thought the engine had stopped. Actually I was just checking out the stall behaviour, but if I had to do a dead stick this would be the plane to do it with. John

Another picture with the proud owner/builder.

Hi, the attached photo shows my Powerhouse flying for the first time in over forty years. The design was by Sal Taibi in 1939. I built it in the mid sixties and last flew it as a teenager in about 1966 or 67. The last flight damaged the wing and fuselage. Since then it has suffered more damage while in storage, and somewhere along the way the tailplane and rudder got lost. I rebuilt the wing using the original ribs and trailing edge but with new spars. The fuselage is all original apart from the covering and adding some bits to allow radio. I built the new rudder and tailplane from the plans but modified them to provide control surfaces. In retrospect it would not have hurt for these to be bigger, but they provide enough control for what is after all really a guided free flight model. I didn't provide ailerons, so just rudder, elevator, and throttle. The colour scheme is as per Sal Taibi's original, but of course done with modern material. My original scheme was dictated by the limited range of colours that were available for womens nighties in the sixties, so it was in delicate pastel colours. The engine is a Saito 61 modified to spark ignition and petrol. It is a bit critical on the mixture settings and likes a good warmup after starting but has bags of power and a lovely slow idle. The original engine was an Ohlsson and Rice .29, which I still have. Ground handling is not a strong point, but it gets off pretty quickly, if not necessarily facing the way it started out pointing. It flies around very nicely in a relaxed manner in keeping with its dignified age. Landings are easier than I expected, except that once it is down and slowing down it tends to ground loop, but slow enough to not overturn . There is no way to taxi it since there is effectively no steering on the ground. I might add a castoring tailwheel. Wingspan is 7 feet, chord is 14 inches. I haven't weighed it with the radio gear, but it used to be 3 and a half pounds ready to fly. It can't be very much more even with the extra batteries for radio and ignition. Thermal soaring would not be a problem...it caught one when I was a lad, had to run a couple of miles after it. Incidently the hill in the background is much further away than it looks. The lense is a 200mm, which on the digital give the equivalent of nearly a 300mm. John Auckland NZ   Edited By John Olsen 1 on 30/03/2014 06:51:06

I had one come off in the air once. The unbalance as it departed pulled the firewall and motor off the front of the airframe, and left them dangling by the wires. The resulting deadstick landing went well, and my son found the prop afterwards. But since then I assemble them with a drop of loctite. John

Well, I don't suppose we can do equations nicely here but one interesting one is: -1 = e to the power of ( i times pi ) e is the base for natural logarithms and i is the square root of -1. (OK, in simple numbers -1 would not have a square root but in complex number theory we use it all the time.) So this equation neatly ties together three important mathematical constants John

Apparently cyparis is a type of cedar. That may not mean a lot since woods of the same general family can vary considerably. I have been using cedar quite a lot in a full size boat I am building. It is light and strong, and good for what I want there, but a bit more open grain than I would want for wing spars for a model. But who knows, the cyparis variant might well be fine. Probably better than some of what I have seen in ARTFs. Macrocarpa is a timber that could be quite good for spars...it is of the cypress family. It needs to be the plantation grown variety, which gives a nice straight close grain. It is light and strong. The sort that comes from the farm shelter belts here in NZ is not so good. I use NZ kauri myself for spars. It is also a great boat building timber, and the Royal Navy used to come out here to get it for spars. It is light and strong and has a very fine close grain...ideal except for the difficulty of finding any these days. More of it was burned to clear the ground than was ever milled. Quite a lot of it went to the UK as boxes to pack butter in. Incidently most of the timbers I have mentioned are softwoods. John

We get that problem at our strip, since the only workable layout puts the strip to the North of the pits etc. (The North being where the sun hangs out in this part of the world, at least when not behind clouds.) So depending on the time of day there is quite commonly a part of the circuit where you don't want to go. Sometime if there are only a few of us about we modify the circuit so you stay at one end and don't go past the sun. But otherwise, the close one eye trick does work for me. I don't think the welding goggles would work, I have a set and when they trigger you would not be able to see the model...you would probably only see the sun. They will trigger on bright sunlight, but they don't much care what direction the bright light is coming from, so when I am welding at the doorway of my shed with the bright sunlight outside they have a tendency to go dark just when you didn't need it. Photochromic sunglasses would have the same problem, they would not be able to tell that you were looking straight at the sun. So the darkness would be the same as when you are looking a bit away from the sun, so either too much for one or not enough for the other. John

Ok, well, on a less sad note...the February RCME has just arrived here in the land of the long white cloud (NZ) and I notice a review of a Staufenbiel Dornier Do 27. Did anyone else notice the registration of this plane? I know it is always bad to explain a joke, but for those unfamiliar with German animals, ente is German for duck...so the registration of this plane is effectively D-Duck. I presume this would have been inherited from the full size example. John

Funny thing, here in NZ it is the summer when our grass stops growing. The club strip develops cracks of unknown depth that you could easily lose a plane in. We also have rabbits that make scrapes in the strip, so nobody shed too many tears when one of the rabbits went through the club lawnmower. Anyone for goulash de lapin? I don't mind too much at home if the grass is growing or not, since my robot lawnmower will happily go out and mow it any time I want, with no complaints or grumbling. John

One suggestion...only ever order what they have in stock. If you really want an item that is not is stock, get the system to email you when it is, and do another order then. Mostly items come back in stock every month or so, but I gather this is not always the case, and your order will be held up until the offending item comes in. John

I've updated my desktop machine, but not my laptop, so I have the option of either. So if you have it on two machines you could consider that for an option. So far the things I have encountered are mostly just oddities, apart from the F16 one acting as an instant kill for the program. When I play on the laptop, I plug it into my sons 40 inch TV in the lounge and get a good widescreen view. John

Well, I have had 21 orders from Hobbyking successfully delivered, using a variety of options. They can sometimes take a while to show up in the tracking systems, and frequently there can be a stage where the tracking system knows about the parcel but does not have it yet...this can take a week or so. Perhaps the ox cart sometimes has trouble getting from the warehouse to the post office. Usually once the tracking system knows about it, it is not too long before it appears. The exception would be where the value is over the GST limit, in which case the local post office takes longer to get a postcard across Auckland than it did for the parcel to get from Hong Kong to here. (BTW, Hong Kong is closer to the UK than it is to NZ.) I've only had a few parcels that I had to pay GST on, and usually I have been hassling them that they have a parcel for me before they notify me...it is annoying because of course I know they have it, but I don't have their reference, different to the postal one of course, so they can't let me pay it and collect it. I don't think it is worth the risk of having the value under declared, I think they can confiscate your parcel if they think there is any funny business going on. Anyway, even with GST, things are still far cheaper than local prices, if they even have the items available. John