Peter Jenkins

Well now I'm confused. Was the performance OK with the engine inverted? If it was, I cannot think why turning the engine to sidewinder config should cause a loss of power. You say that in the inverted engine case the tank centre line was in line with the engine carb. That is a good position and should not have caused a difference in mixture when inverted. I had thought that the tank was higher than the carb and that would give rise to peaking out or running lean when inverted. You say that there was a good smoke trail - without seeing how good I'm tempted to wonder if you might be running a bit rich. Perhaps you can let us know if you feel you have got the engine running at peak speed and then backed off the needle valve to drop rpm by 300-400 revs. Have you weighed your 3D model and compared it to the Wot4/Acrowot weights?

Thanks for posting that link Jon. Another take away is that he recommends "training for the difficult things". It's easy to fall into the habit of doing the stuff you find easy but what will catch you out is when things get difficult. You don't have much time to learn then.

An alternative solution, if it's possible, is to leave the engine mounted inverted and move the tank so that it's mid point is now level with the carb. That way you only have one job to do. As Allan has pointed out above, you will need to re-drill the engine mount holes and put blind nuts on the other side of the firewall to secure the mounting bolts. You will need to remove the fuel tank to do this. Unless you are very lucky with the design, this will be a fiddly job but one that will be made a lot easier by using locking forceps (you can find them here). They are an invaluable aid in many situations where space is limited. That's why I suggested that you consider re-locating the tank to a better position.

I'm slightly confused. You say you mounted the Irvine inverted to suit the front cowl but that side mounting it will raise the thrust line. Are you going to remove the cowl completely? If not, then your engine thrust line must be the same if the prop shaft is still in the centre of the cowl. From your description of the engine peaking when flying inverted, your tank position is probably the cause being too high when upright which is why the engine leans out inverted with the tank now low. Just rotating the engine 90 deg to sidewinder should raise the carb and you may well end up with the needle valve at the same height as mid tank - that will solve the leaning out problem when inverted. If the tank centre line is still above the needle valve when the engine is side mounted then you will need to lower the tank height. I cannot see how you can get the prop shaft to match the cowl and end up with a different thrust line whether inverted, side mounted or upright for that matter. Have I misunderstood your question?

I've had good results with a JMB canister on a DLE 35 but the model has a pipe tunnel. JMB also do Pitts type muffler but I don't know how good they are compared with the canister. You can find them here. Might also be worth trying a 17x10 prop to get the tip speed down from the 18" prop. Also, worth installing a trumpet intake and getting the intake noise moved to inside the airframe. Every little change may help to get the noise down.

Simon, the reason for using throttle cut on an electric motor is to prevent the motor activating if the throttle is accidentally opened when the ESC is armed. This could be a neck strap being dropped onto the Tx for example. Better safe than sorry I say!

JR XG11 for me. Does everything I want apart from telemetry and a 3rd party product covers that. I don't have a vast fleet so the 11 Rxs I have will do very nicely. I also bought a second hand XG11 just in case my first one went sick. If I do decide to change at some point, my current next favourite would be Jeti.

Martin, one could also make the case for the Hurricane as that was the aircraft that accounted for the majority of German bombers shot down in the B of B. You are right about the bombing of Berlin which led to that most important of military rules - maintenance of the aim. Hitler's decision shift the target from Fighter Command stations to London was what gave the RAF the time to recover. Had it not been for Hitler, there wouldn't have been a 2nd world war but because of his many strategic and tactical errors he was also a great help in the defeat of Germany. Did you know that at the end of WW2, the RAF had the capability and bases to photograph any target anywhere in the world thanks to the PR Mosquito. Nothing could shoot it down from the ground and no fighter was fast enough to catch it apart from the Me 262. However, the turning circle of the 262 meant that it was easy to avoid. The Mossie crews waited until the jet had lined up on them and then turned hard left or right. By the time the 262 had repositioned for a second attack it was out of fuel. The Far East was the Mosquitos Achilles heel. The heat and humidity meant their glue joints started to fail.

Ronos, you may not have noticed but the latest BMFA Handbook now has as part of the before every flight checks a Rx battery voltage check. Every pre-flying session check also includes a Failsafe and Range check. All of these checks are there to prevent what you have just suffered. Worth doing those checks.

You should never leave a LiPo connected and in the aircraft when you are not using it. The current drain with the Powerbox switch is minimal during the time of operation. I always fit the LiPo before flight and remove at the end of the session. You need to have a LiPo outside the aircraft to charge it. The same does not apply to LiFe cells.

When I use a 2S LiPo I use a Power Box Digiswitch. It's a bit expensive but is software driven and has an inbuilt LED to provide a warning of low voltage. However, if you are using on-board telemetry, then all you see is a voltage of 5.9 v. So, by the time the LiPo actually reaches 5.9 v it's done for. I am now also using a 2S LiFe which does not need a voltage regulator as it's 6.6 v off charge. I'm using this setup in a 35 cc petrol model with another 2S LiFe pack to supply the ignition system. I use JR servos and they are fine with that voltage. An ordinary good quality switch is fine with a 2S LiFe pack.

Well done Gary. I've always found that aerobatic aircraft maiden flights, provided the CG is in a safe place, are usually uneventful - but it doesn't stop the butterflies as you get airborne for the first time!

Great technique for cutting a carbon spinner. I have only cut alloy spinners and done them by just modifying the existing cutouts. I like the process you used.

My experience is with an AGM 30 and DLE 35 RA in my Capiche 140. In both cases, I just repositioned the float chamber cover so that the vent hole faced backwards. In neither case did I get any problems with the engine running erratically. Could have been pure luck of course.

Well, the major reason for using a trumpet intake extension is to get a steady stream of air into the carb. The DLE carb ends with a flat face and if there is a bulkhead close up to it there will be undue turbulence introduced as the carb draws air in. A trumpet intake stops this happening. The wide intake provides a smooth entry for air which is then smoothly accelerated as the trumpet cross sectional area reduces to match that of the front of the carb. This provides the drop in air pressure that is required to enable the fuel to be sucked into the intake (actually it's the atmospheric pressure in the float chamber that pushes the fuel into the carb intake). The air temperature is also generally lower than that being drawn in from the engine compartment. Whether you choose to fit a "Brian Wnch" style air filter or not, the fact that the air intake is now inside the fuselage will also attenuate the intake roar - ever listened to your car engine running without the air filter fitted? Darn noisy! So, there are many benefits to fitting a trumpet intake to the standard carb. You still awake Gary?

Posted by Martin Fraser on 14/03/2018 18:37:08: Ok folks, I'll keep it as is i.e. no brake - every little helps to slow down the approach speed! Many thanks for the input, Marty Hi Marty, at the risk of stating the obvious, the elevator controls your speed on approach. So, if you want to slow down, and you don't have obstructions on approach, then a flatter approach using power to maintain the required rate of descent, is the best way of proceeding. Re braking in aerobatics when flying with electric motors, ESCs like the Jeti Spin 99, allow you to vary the amount and ramp up of prop braking so that you can adjust how much drag the braked prop provides and how quickly it ramps up. Remember, these are 21-22 inch props, so that's quite a lot of drag. This type of brake does not stop the prop dead as then there is virtually no braking. 3 blade props also increase drag over a 2 blade prop.

Apparently, Larry Page, Google's co-founder, has been working away in New Zealand to develop an all electric flying taxi with autonomous flight capability. Link. Could form the basis for an interesting model aeroplane as well.

Gary - excellent technique. However, I note that you didn't have the canopy hatch installed. On my Capiche 140 the pilot I used weighed 100 gm! That had an effect on the CG! You might want to check the CG of the canopy hatch to see if it falls forward or aft of your chosen balance point.

Gary - great work. At the risk of stating the obvious, in your photo of the assembled aircraft and adjacent to your comment on the CG, I note you do not have the cowl fitted. On my Capiche 140, the cowl weighed 8 ozs and is well forward. I would expect your cowl to be heavier than that so I hope you had the cowl attached (and prop and spinner) when doing your CG trial balance. At least it will move the CG forward if you didn't have it on. As you obviously know, CG optimisation can only really be carried out by flying and trying different CG locations until you find what suits you - which might not be the one selected by the designer.

Gary, did you say you were going to exhaust the engine cooling air via the pipe tunnel? If yes, then you do need to make sure that the intake area is matched by an exit area that is twice as much. Looking at the size of the holes you have made in the pipe supports it may be marginal. I had an exit I cut in the bottom of the cowl to exhaust the engine cooling air. I also blocked off the intakes either side of the spinner and cut a hole in the cowl to allow air straight onto the cylinder head. This was on a Capiche 140 which had a DLE35 RA with canister. The pipe tunnel cooling was just to keep the canister cool.

Jez, the point is that any unmanned vehicle being operated beyond the line of sight of the operator, regardless of whether the operator is military or civilian, will be governed by the rules being proposed. The problem the model aircraft world has is that there are a lot of small drones that are being bought and operated by people who have no idea about the way UK airspace is governed. Unlike common land, there is no such thing as common air. So you don't own the air above your own property - the Government regulates its use. Legislation is not going to stop those who break the law - otherwise we wouldn't have prisons - but a high publicity about the penalties for breaking the law might deter a few from endangering others. At the same time, we all want to see the UK thrive by making use of new technology - driverless cars being another case in point - so it is inevitable that new technological solutions either to address existing problems or to create new opportunities is an unavoidable situation.

Posted by Sam Longley on 16/02/2018 17:40:50: Have only seen him on site once so have no idea what he has been developing since. Neither have I seen any other models like it: but if the authorities preparing the legislation saw that aeroplane in operation the proposed rules might be somewhat more stringent me thinks. Sam - you can buy these flight management systems off the shelf these days and the authorities are well aware of them. Currently, it is illegal to use this functionality to fly the aircraft out of the operators line of sight. That's where the wide boys have been pushing it and breaking the law.

Posted by Jez Saunders on 16/02/2018 16:50:42: As for military use of drones I would have thought there would all ready be rules and protocols in place. After all this to do with national security, world peace and so on. Not saying that they fly them were they want or they are above the law but they can do pretty much what they have to do, fly to were they have to, do reconnaissance, shoot something and come home ! So not sure how they come under any new regs ? Jez, I'm afraid that the Military cannot do what they like with Drones. All the drone flying that takes place is either in the confines of one of the ranges in the UK or else limited to the theatre of operations unless, the airspace is closed by the civil authorities to allow Military unmanned aircraft to be flown in National Airspace. The Military have a programme that has been running for many years to try and demonstrate that it is feasible to fly an unmanned aircraft (drone) safely alongside manned aircraft - the main issue is to replace the pilot's function of "sense and avoid". As far as I'm aware that capability has yet to be demonstrated in the UK and any where else for that matter. The way the Global Hawk is operated is that it takes off and flies in circles to climb out of the normal civil airspace and there is a NOTAM issued that closes the airspace to all manned (and other unmanned) aircraft while this happens. The Global Hawk operates above 55,000 flt and so can fly where it wants within that Nation's airspace. On recovery, the same procedure applies. The problem with civil operation of drones is that it's only worth doing if you can go from A to B and not A to A especially if B is in another country. That is what EASA is grappling with. The one area that the military does have a dispensation is to be able to fly "not below 250 ft AGL" anywhere in the UK that they are not specifically excluded from overflying. This includes foreign air forces that are operating with the permission of HMG.

Posted by MattyB on 15/02/2018 13:26:15: Where you may lose out is in setting aileron differential to avoid dutch roll (important on high a/r soarers; you need both ailerons on separate channels to be able to tweak that from the TX, though you can obviously set some up mechanically). Sorry Matty, Dutch Roll is something completely different from adverse yaw which is what you are describing. You would be extremely unlucky if you ever suffered from Dutch Roll with a model aircraft. Also, while full size gliders have differential on their ailerons you still need a bootful of rudder, in the direction of turn, to fly a balanced turn.

Jez I think you are looking at the situation from the wrong angle. Drones, or UAVs as they were once called, have been gaining increasing use in the military for the past 15 years. They range from something like the Lockheed Martin Desert Hawk, Boeing Scan Eagle, QinetiQ/Airbus Zephyr to the Northrop Grumman Global Hawk. None of these is allowed to fly in Civilian Airspace unless the airspace is closed to all manned traffic first. The Desert Hawk and Scan Eagle could easily be described as model aircraft. The Scan Eagle (10 ft wingspan and 10 cc petrol engine) has a duration of 24 hours and is/has been used extensively by the US in military operations for reconnaissance. Then you come to the killer drones such as the General Atomics Predator/Reaper. The Global Hawk stays out of the way of commercial traffic by flying at 50,000 ft plus - but it needs to have the airspace cleared to allow it to get to and return from this height to its operating airfield. Zephyr flys at 70,000 + ft but also needs to get there and back. In aviation today, the barrier to entry to manned aircraft production is so high that it is high risk high cost activity. Conversely, getting into the Drone area is relatively low risk/cost and many nations as well as companies new to aviation are jumping in because of the commercial opportunities presented. These cover a huge range of possibilities from agriculture, environmental monitoring, security, surveillance (Coast Guard, Fisheries Protection) down to Estate Agents wanting to take photos of their clients' houses and so on. The problem is how to integrate these unmanned assets into the existing airspace. This can be done either by segregating the airspace used by these vehicles or else by fitting them with sense and avoid technology (yet to be produced at affordable cost) to allow them to mix it with manned flight and other airspace users such as us. What we are seeing is EASA going down the segregated airspace route. The EU has decided that there is a significant amount of business to be gained by embracing this new technology and EASA was given the job of making this happen. As BEB says, by dint of excellent lobbying by the model aircraft world, we appear to have got pretty much what we were aiming for which is, as near as damnit, what we have now. Having a go at the admittedly careless use of small commercially available drones, is merely a tiny part of the whole issue with which the EU and its organs is dealing. That was reflected in the way they approached the problem originally - that is, they were totally ignorant of what we in the model aircraft world do and how we operate. I hope that makes you feel better. It is not an issue of being a kill joy more one of not seeing that this is part of a very much bigger picture. Getting rid of model aircraft sized drones will not make the bigger problem go away. That requires constant vigilance to make sure we are not stopped from operating by officials who have no knowledge of our sport. Edited By Peter Jenkins on 15/02/2018 23:34:53