John Emms 1

Perhaps I should have waited to see what was on offer at the Nats this weekend, but for various reasons (not least being it was the last one), I have bought the World Models 1/4 scale Piper Pawnee. **LINK** I wasn't sure about the extra weight of the Pawnee with the MVVS 40 unpiped, but having seen video of this model flying with a Saito 40cc, and just as I would like it, I am confident that I will be happy with the outcome. A lot of money? Yes, but I have everything to go in it - and I deserve it, or so my wife tells me! Regards, John

Thanks for the tip Adrian. A search found this: **LINK** The Decathlon fuselage internals are at 7.35. I guess the super light weight comes at a cost.....

I have the opportunity to buy a Pilot RC 27% Decathlon at a relatively attractive price. I like lazy aerobatic models (I should not have sold my Rascal 110), and my MVVS 40 would appear perfect for the Decathlon, from seeing the factory videos with 30cc and 55cc engines. I have a 2,1m limit for models to fit in my trailer - the Decathlon fits. So, are the Pilot RC models THAT good? I only have space for one more large model, and I also have a spare MVVS 26. Is there something else that I should be looking at? Thanks, John

I would absolutely agree with the advice to go along and see what excites you. The other factor is that what would be suitable, and even desirable, for a 4 court plus hall (typical sports centre) will not work in a 1 court hall (the typical village hall). I only fly fixed wing, and whilst the Ares would be perfect for the small halls, the electrics in the ones I have experience of have been variable in quality. It is a pity that Horizon have pulled out of the small indoor market with the exception of the Night Vapor - that I find particularly tame (mine may be broken for the receiver....) The Mini Vapor (with 70mAh batteries) and Spacewalker are excellent if you can get hold of any - I have both, and they are NOT for sale! I have flown two of the Micro Aces kits, they are excellent, and originally designed for use with Horizon/Spektrum gear - highly recommended!

That wing is pretty much "normal" Czech construction. The laminated spar is EXACTLY of the type used on the Pelikan Swift and Big Swift (except the Swift is balsa, carbon, balsa), and the first job in construction was to do final adjustment on the washout of the tip panels, and adjust the centre panels). In fact, I adjusted one wing panel OVER 10 degrees each way to prove the point. Where there are vinyl markings, follow the technique, but hold the iron slightly off the surface, and you will see the vinyl adjust with the wrinkles. Where are you? If you are local, I could do it for you..... I am buying a Obag Donald that I will pick up at the Nats, and know that I will need to adjust the wing panels - it's easy!

Hi Bert, you are at a level of repair that would suggest the engine being serviced by the designer. At MVVS they would replace parts, and upgrade as required. I am also wondering if you have an early 26 (identified by no "hump" in the bottom of the crankcase - there are also a few early 26 with the hump). Later parts have "N" for new in the part number. As you say you have a big end bearing problem, it may also be wise to replace the crankshaft because the crankshaft provides the inner race for the roller bearing. I hope I do not miss stages out, this is easier to learn at the bench than through a discussion group! The piston/liner/conrod assy is removed by heating the rear of the crankcase, until the liner falls out of the top of the crankcase. The prop driver and woodruff key need to be removed before the crankshaft can be pushed out. The crankcase will need to be heated to remove the bearings. Reassembly: The crankcase will need to be heated to fit the bearings. The printing on the race goes to the outside, and use the crankshaft for alignment. When fitting the conrod, make sure that the orientation is correct. There is a larger cut out on one side of the piston skirt, and the big end bearing printing is on the outside. When fitting the gudgeon pin retaining clips, "screw" the clips in, holding the tang with needle nose pliers. When fitted, the tang on both retaining clips must be vertical. When fitting the piston to the liner, make sure that the piston ring ends line up with the pin in the piston ring groove. There is a taper in the bottom of the liner to help fit the piston. Fit the big end bearing to the crankshaft (so you can still see the printing on the big end bearing), and heat the rear of the crankcase so that the piston and liner assembly falls into the crankcase. The liner may need a final push. Now check that everything is aligned correctly. Good luck! John

Whilst I have no experience with the Top Model gliders, it is not unusual, and even quite common to find this with Czech models. The covering on Czech models is always polyester, normally Oracover, but may be polyester Solarfilm. The covering provides the rigidity for the wing panel. THE techniques is to set an iron to normal shrink temperature. Twist the panel (or part of the panel) affected past the required point. You will see wrinkles appear in the covering. Run the covering iron slightly away from the covering, and over the wrinkles on both sides of the panel until you see the wrinkles go smooth. Let the panel cool a little, and then check the panel for washout. Repeat this until you get the panel exactly as you want it. You may find that slight correction will be required after a week or so, but after that slight correction, the panel will be permanently set. Whatever you do, do not let a hot iron touch vinyl marking. This sounds a lot more involved than it actually is - oh, and this is from tech support of a Czech glider company.

Hi Steve, It was Sandra and I who had started to suggest that customers go direct to MVVS for certain items, particularly if they wanted them quickly. There are benefits in stocking MVVS parts, but prices have risen considerably, both as a result of normal inflation in other parts of the world, and the dramatic drop in the £ against the Euro. Yes, many of the MVVS sales have been to other countries. Bert, To help identify the petrol engines: If the head has 30 or 40 printed on it, that is what the engine is. If there is no printing on the head it is a 26 or 35. Of course, I continue to be happy to provide advice - so long as it is not stepping on Steve and Aaron's toes. Unfortunately I can no longer provide spares! Regards, John

Erfolg makes a really good point, that if the outer two cells in a 3S pack are warm, then the inner cell is going to be warmer - and it would appear, at greater risk of short life (though I have no evidence to support this). On reliablity of different brands: A handful of brands can be from the same manufacturer, but I have not been able to recognise which brands share a common manufacturer - and there are also more than a couple of manufacturers.... I have been using the Pelikan Ray and Foxy brands, partly for obvious reasons, and partly because Daniel Pelikan can choose from any manufacturer (and Daniel would never knowingly sell me anything that was less than good). I also have an internal resistance meter, and although the Ray are more than capable of supplying the current I need, I will probably stick with the lower resistance (and heavier) Foxy in future. I suspect that the same cells as the Foxy are Overlander's premium range of batteries - the surface mount LEDs on the end of the pack help with identification.

HI Erfolg, sorry, I don't have a real name. You got me thinking. I or we got used to the idea of really opening the inside of the fus up to air freely moving through, which was a real shock after the idea that everything is packed inside and wrapped in foam! The big fear was things breaking loose, so batteries always have been stuck to a light ply plate with self adhesive Velcro, and then have a Velcro strap to make sure the batteries stay in place. I said we never had a problem - but I remember one: The LN Model Accord 2200 2,2m was a freestyle or 3D model designed for 40cc. Libor of LN then produced a lighter version intended for 10S electric - I bought two as demonstrators. In hindsight, Libor had allowed for cooling air around the cowl that contained the speed controller, but had not allowed for cooling air through the fus that contained the batteries. We had the best 3700 cells available at the time (25C), and peak power was conservative at around 65A. At the end of every flight I was aware that the batteries were warmer than I was comfortable with, and became very slightly puffed. The same power system with the very same batteries was used in my Rascal 110 conversion. The batteries were in a ply box or tube that was in the tank bay, and slid in under the cowl. The battery box had openings at the end, and cooling air could escape through a hole cut in one of the side windows. The batteries were hardly warm at the end of the flight, and I was never concerned about them - other than knowing they had slightly puffed during use in the Accord. I had always thought that people suffering short battery life were being sold cheap batteries, using them at high currents, and not balancing regularly, but I think you could well be right, that good levels of battery cooling are a large part of long battery life. Yes, I also agree with you that a small amount of air that is allowed to flow freely through the fus does make a huge difference. Regards, John

Of course, there are a mass of solutions to this electrification. On further thought, to fit an outrunner, I would cut a large hole in the firewall (for cooling and for access), and make a new front former with cooling and mounting holes to fit the motor. The fuselage sides, and thin ply all around the "cowl" will provide a great deal of rigidity. By mounting the motor at the front, it makes the whole stronger than having the prop mounted on the rotor, that has a thin alloy tube cantilevered off the " mounting plate" inside the motor. Using a radial mount off the firewall, this might be handy **LINK** Regards, John

Hi Nigel, there is little that I can add to what has been written so far. Controller issues. Your 22/30/4 wants zero to around 6 degrees of timing advance, though the Foxy's tended to work best with the Megas at 22 degrees (the same as outrunners). If the timing or frequency is not at optimum, that could result in a build up of heat. I found optimum prop on the 22/30/4 to be around 11x5,5 running at maximum rating of 450W on 4S. On the gliders, the top of the fin being open, with holes in the motor mount to allow cooling air through the motor, and to be drawn between the front of the fus, and the spinner always worked well. On power type models, we always opened up all the formers in the fus, and generally cut a large hole underneath the rear of the fus for cooling, and that allows air in or out as required. Of course, air needs to be able to flow through the motor. For your ESC cooling, I would simply open up a hole in the bottom of the firewall that will allow air to flow through the fus, cooling both the ESC and the batteries. For a general rule, with glow models, I always sealed them as much as possible, and with an electric model I open up the inside of the fus to cooling air as much as possible - and yes, that still feels strange! Using this strategy, we (as a test and display team of 5) never had an issue with overheating. Hope that helps, John

Hi Keith, You will need the battery fairly well forward because you will lose the weight of the engine in the nose, and it normally works out about right for the battery to be in the tank bay. Of course, you could carve out a screen, but I would use a piece of balsa around 1/8th or so in front of the bulkhead that forms the front wing mount - you can then build the normal screen and tank bay top on the additional balsa. You may need a couple of balsa or hard wood strips to reinforce the top of the now open tank bay. I suggest doing a search on Sig Seniorita electric, or Seniorita electric conversions for ideas about the battery hatch. There is an electric version of the Seniorita, and many Senioita kits were converted to electric. Oh, and I want one!

Hi Keith. I have flown a Flair Cub a couple of times, and it is a really nice sports model/trainer. The one I flew was adequately powered by an OS 40 LA, so 4 series LiPo power systems are the order of the day (running at around 450 to 500W). As designed, 36mm diameter motors fit in clam shell mounts, and fit straight into the engine bearers (I did this on my DB Moth converted from Saito 40 to Mega 22/30/4), but I am not aware of any suitable motors that may be considered "affordable". The alternative for outrunner motors would be to move the engine bearers further out, and then use the plywood that forms the cowl to link the front bulkhead to the rest of the fuselage. You will need cooling holes in the front bulkhead (the one that the vac forming glues on to) that also forms the motor mount (with the shaft sticking out of the front of the model). You will find that any motor you use will be about half the weight of the appropriate engine. You will find that the battery wants to be somewhere around the tank bay area to balance. You could simply have a ply plate in the centre of the tank bay as battery mounting plate with a section of the lower fuselage either left open, or used as a hatch, and then fix the battery with Velcro and Velcro straps. Because of the size of this model, it would be better if the whole of the tank bay and windscreen assembly was removeable with a hatch catch, or taped on one side, and the other held with magnets (I have used both methods), and then the battery is easily accessed whilst standing on it's wheels. Hope that helps, John

At £31.95 it is possible to pay less for this type of speed controller, and it is possible to pay far more, but I would suggest it is not possible to find a better speed controller, or one easier to use: https://www.esoaringgadgets.co.uk/speed-controllers/jeti-speed-controllers/jeti-eco-line-speed-controllers/eco-40

Yes, of course this is a classic sign of poor connections between motor and ESC. Smell the motor for signs of burning, check the motor for loose magnets, and also smell the ESC for burning. And again, check the motor and ESC with other motors and ESCs, but only test them very briefly for fear of burning out other motors and ESCs. Spending my own money on this size of ESC, it will ONLY be the Jeti ECO 40. Of course, the Jeti Advance would also be on my list. We also found the Foxy to be very Jeti like, and super reliable - from a sample of hundreds.

The alternative is to phone MVVS, but again, keep the English simple and stick to the point. The telephone number is 00420 545 211 683. Josef is technical support [email protected] Full contact information is at **LINK** I have 6 petrol engines, and 5 of those are MVVS (the other is Zenoah simply because I needed a magneto engine).

Hi Nigel, Like almost all European companies, MVVS have a 2 week summer shut down, but I do not know when that is. The e-mail is [email protected] Experience tells me to keep the English simple to avoid misunderstanding, and keep right to the point. Where they can, the latest owners of MVVS are still supporting engines over 25 years old. Beware that there is a different culture to e-mail with every single European model company that I have dealt with, and that is if you would not like the answer, you will not get a reply. I suspect that MVVS are incredibly busy developing and producing engines for UAVs

Sandra and I gave all of the MVVS spares that we had left to Steve. I have no idea if Steve will be continuing with MVVS, but EVERYTHING is available direct from MVVS, Simply send an e-mail in English. An alternative source for the MVVS petrol engine spares is, of course, Horizon.

Posted by Tim Hooper on 06/08/2017 13:11:53: We don't travel light. For the pair of us (+ small dog); 5 -berth caravan c/w awning, containing several models, generator (for the hairdryer), guitars, too many shoes, cosmetics, too many clothes, tec..... Much like a colleague who keeps a collection of cars, a campervan AND a motor home. I am sure that one day I will see the light!

I guess what can be used all comes down to budget, storage, and time for maintenance. Over the last 40 years, I have been on the verge of buying caravans, various types of trailer tent, and converting the van to a campervan, and all have been rejected for various reasons. Of all the many tents I have owned and used, by far the best is our current Vango Icarus 500 that takes up little room when packed, but provides a good living space for the two of us plus dog. We have been in that tent during the most horrendous storms, and a replacement is currently no more than £200 should we need one. Our latest (and best) air bed is an Aero Bed Active - yes, £80, but worth every single penny. Furniture is two folding chairs and a water proof camping table with adjustable legs. Cooking is taken care of by two Trangia methylated spirit cookers that can be used inside and out, and take up little room when packed (we mostly use only one). Light (and lots of heat) comes from a 35 year old Coleman kerosene lamp. For eating and drinking we have lightweight stainless steel cutlery and real ceramic mugs. Sandra's absolute must have luxury is two glass wine glasses that she keeps in a box. Everything stores easily in a spare wardrobe, and fits easily in the back of my Suzuki Swift. I intend to be at the Nats with a 3 person tent (that has a small porch), single lightweight air bed, chairs, table, and one Trangia - see you there!

Whilst it would be quite normal, and very sensible, to have a weight limit and a limit to noise output, I do understand that the council say they need SIZE limits. I would avoid getting too complicated in all of this. At what point does a helicopter become a multirotor? Does it become a multirotor when directional control is not from a tail rotor, or does it become a multirotor when it has more than one main rotor? What about contra-rotating rotors? Is a scale Chinook a helicopter or a multirotor? You already have a size limit of 1,5m across the rotors of helicopters, with a 10cc or 1500W limit, so why would that not work for all rotorcraft? And taking up (again) Frank's second point, I have flown with helicopters, both outdoor and indoor, and we both wanted to use the same bit of airspace, but the typical flight paths of flying fixed wing and helis are clearly different. Woodspring cure this issue by having separate areas for flying fixed wing and for flying ALL rotorcraft - and this has been a very successful, and safe, arrangement for many years. I hope that is of some help. Regards, John

Posted by Dave Hopkin on 03/08/2017 18:15:14: Helos - 1500mm Rotor Diam and 0.60cu/10cc or 1500W Electric Whilst I am not sure why the helicopter power limits could not be the same as the fixed wing power limits, do you not already have a size and power limit for rotor craft?

I have made my own foam wings, and the answer is the lightest density of expanded polystyrene foam you can find. I was warned about recycled faom that could have unwanted lumps in it. I tried bonding obechi veneer using PVA, and that takes too long to dry. I did have success with Copydex, but that leaves no time for errors. The best foam wings I have ever seen are Reichard, and they use extremely low density expanded polystyrene. The light weight balsa outer skin is bonded using lightweight glass cloth and epoxy. Clearly, the glass cloth provides the strength, and the balsa allows an excellent finish. The Reichard foam wings are no heavier than the built up wing versions. HTH, John

Not wanting to detract from Braddock's pension fund, I do feel that there may be some misunderstanding as to where the Merco 35 fits in all of this. I found the Merco 35 totally useless in 40 type aerobatic models of the 70s, and as a low power loop scavenged engine, it is probably less powerful than the original OS FS 40 (which I also owned and used, and saw giving perfect service in J 60s). The FPs are extremely refined, start easily, and run at low throttle settings for very long periods of time. Unlike the Merco 40, 49, and 60 (all of which I have owned and enjoyed, and all had alloy pistons), the Merco 35 has a cast iron piston, which does provide greater vibration, but has a character all of it's own!