Peter Jenkins

Colin, interestingly, my experience of the low cost Hitec servos is that they centre better than their more expensive counterparts. Perhaps you really do need the Hitec servo management gizmo.

Percy, with many F3A pilots flying electric, they tend to use plastic geared servos which give better resolution than metal geared ones and, with the lack of vibration with electric power, the gear trains last well. It is far cheaper to replace the gear train than buy new servos as well. Most have now gone for the brushless variety of servos to extend life further. I know that often folk sell on the bare airframe and keep the servos, motor and ESC for their new ones. Those who are still flying YS powered birds may, no doubt, do as you suggest.

Woops posted twice so deleted this one. Edited By Peter Jenkins on 04/12/2016 17:32:11

Sorry - trying to post from my smart phone! Edited By Peter Jenkins on 04/12/2016 17:34:00

When I came into F3A I was told to use only Futaba or JR servos. I'm trying some Align servos which I have yet to fly but they seem to centre perfectly. These tend to be expensive but servos are what give the aircraft it's feel and are a vital link in aerobatics if you want to take things seriously. Some good reports on Savox as well. I have some Hitec TG 7000 series in my Capiche- these are 25 Kgmm servos recommended by Weston. You need to buy a Hitec gizmo to adjust resolution and deadband but I never did and both rudder and elevator do not centre repeatably. I know that in the IMAC world Hitec servos are popular but I can only speak from my own experience. You pays your money.......

Adrian, it is well worth checking to see if you get very slightly different centre positions when returning a control surface from both sides. With an F3A aircraft, even the smallest deviation from a true neutral will make it difficult to fly consistently. On a 2 mtr Vanquish I had used Hitec 5654 (or something like that!) servos and when I asked a GB team member for his opinion on the aircraft's trim, he said it was impossible to trim the aircraft to get level flight from a vertical dive/climb as once the stick was centralised after pushing/pulling to horizontal, the aircraft would either climb or dive slightly. Having replaced the servos with another make, the control surface returned to exactly the same place when returning from either side. Believe it or not, that made a huge difference to the workload on the pilot! You could pull/push to horizontal and then not have to worry about the aircraft deviating from horizontal. Pilot workload in aerobatics should be expended on flying the manoeuvre and not struggling with the aircraft/equipment limitations.

Posted by Biggles' Elder Brother - Moderator on 30/11/2016 11:17:30: "Politics is the art of the possible" - it's possible for us to get a very good deal - one that might even protect us, if we work at it. This I believe is what is going on in the background now - or at least I fervently hope it is! BEB BEB, that is exactly what the BMFA, with Dave Phipps as the man on point, is doing right now. The link I posted to the FAI site which has the document Dave drafted on it, has, I believe, made maximum use of the FAA ruling on this same area. The FAA outcome, if adopted by EASA, would answer most of the points raised in this post. However, unless the pressure is kept on EASA it will take the path of least resistance! The BMFA is focused on not letting that happen and I commend them for that persistence.

Posted by Tim Cheal on 28/11/2016 19:28:58: Wow, bugger the landing lights - which are indeed impressive - but what about that sound. Marvellous... Tim

Posted by Biggles' Elder Brother - Moderator on 29/11/2016 20:43:44: Peter, you are using a definition of autonomous which of course is perfectly correct, but it isn't the usage common in the civilian drone world. When I talk of "autonomous" I don't mean the drone is flying making its own decisions in effect mimicking a human pilot. That is currently still some way off as you rightly say. No the autonomous I am referring to - and as used by most non-military drone users - is as I describe above, effectively following a pre-programmed GPS path. That is fully realisable now. BEB In that case BEB it is automatic and not autonomous since there is no on-board capability to re-route should it be needed for any reason.

Posted by kc on 29/11/2016 14:13:56: The real reasons that there is any proposed legislation is surely so that the military can have the only drones flying just anywhere I worked for a company that was, and still is, deeply involved in UAVs principally for the military. They have been working on autonomous operation of UAVs but this is just not going to happen - semi autonomous might work but the need for a human to be involved in critical stages of the operation - in the military case, weapons release - will mean that you still need pilots/operators to remain in the loop. These UAVs range from something like the Northrop Grumman Global Hawk (30 hr flight duration, fully autonomous flight from take off to landing and cruise at 65,000 ft) to small hand held devices that can be used by troops to see what's around the corner of a block of flats in a urban conflict situation - looks like a model aeroplane with a camera. Another UAV that's been around for some years is the Scan Eagle, now owned by Boeing. This video clip shows how this small 2 stroke petrol engined craft is operated. Max weight is 22 Kg and endurance is 24 hours plus! Recovery is to fly at a dangling rope and have that slide down the wing to a hook at the tip. Simple - no need to land in the normal sense. This works at sea as well. Love the box it comes in! No one has yet come up with an adequate sense and avoid solution so all Military UAVs are still required to fly in segregated airspace. That means either a military range, or in an operational theatre where the military has control of the airspace. In any event, the sensors will represent dead weight and have an electrical power demand that will tax small vehicles. An example of a UAV use that might impact us is in the agriculture industry to use UAVs to assess crop health using hyper spectral sensors to determine which area of the crop is diseased or short of water so that the farmer can take specific remedial action.. These UAVs will usually need to be flown low to make sure the sensor is able to achieve the desired resolution. They could do this now with a pilot operated MR Drone but the more likely vehicle will be a fixed wing device as they can generally carry a heavier payload and are much cheaper to make and operate - not so many moving parts for a start. One could see that such an operation might impinge on model flying but then so does crop dusting with full size aircraft. As I say, if the military hasn't yet found a way to do the sense and avoid bit then the civilian world is normally loath to put its hand in its pocket to do the necessary research to come up with a solution - but someone like Google might as they have deep pockets. If they do find a way of doing that that meets the regulatory demands then that would really open up the option for UAVs to avoid other aircraft in the uncontrolled airspace area - that's the most difficult task as you still have a lot of non radio full size aircraft relying on the see and be seen rule to effect safe flight. So, while Google has been given permission to do some trials I see that the new minister is in no hurry to take this trial forward. There are just too many unknowns to risk getting egg all over the regulators face to take such risks lightly. Ultimately, EASA will need to be convinced that the solution proposed by UAV operators is sufficiently safe to warrant its use - that will take time and money. Where does that leave us modellers. Well, I think it will take some time, but I have some faith in the activities by the BMFA in putting the case to EASA (remember Dave Phipps who is the Chief Exec of the BMFA is also our representative on Europe Air Sports and his drafts to the FAI have been submitted to EASA by them) and there is now a move to form a pan-European model flyers group, numbering around 500,000 to lobby EASA as well. I believe something sensible will result as it has done in the USA. I think the Irish CAA jumped the gun and have implemented something that is not well thought through.

What underlies all this discussion is the almost lost art of trimming an aircraft so that it flies in a way that suits you. You set it up to what the designer states to make sure it's going to fly more than once - mind you some instructions give a dangerously rearwards CG which leads to a horrendous first flight. What pilots should be encouraged to do is to make small changes, one at a time, and see how that affects the feel and handling of their pride and joy. I suggested a friend fly my Wot 4 as he had one. His comment when he landed was "this is so much better than my aircraft what have you done to it?" So, we set to and made his aeroplane fly as well. This covered finding the optimum CG position for him, then addressing control throws and then expo and finally tweaking his engine so it ran properly. At the end of that, he was delighted - until he had a moment of confusion and returned it to matchwood!

Posted by stu knowles on 28/11/2016 22:32:41: I have read that dialling in 30% expo is needed to give a linear response to a rotary output servo. It is undoubtedly true that a rotary servo will give greater linear movement per degree of stick movement around the centre that at the extremes of travel (subject to all linkages being set 'square' . I have no idea if the 30 % value carries any validity, someone with a maths degree can work it out and report back. I read a trimming manual written by a very experienced Australian F3A pilot. He gave 35% expo (in the sense of reducing movement around neutral) as providing a linear output to the servo arm when compared with Tx stick movement. Most F3A set ups suggest around 10 deg of movement on elevator and ailerons and around 25 deg on the rudder and 30-35% expo seems to work well with these settings. You tend to move the sticks a long way in F3A to achieve the required smoothness, accuracy and manoeuvre size demanded of this discipline. Some F3A pilots use expo to give them the fine control needed for manoeuvres with much higher movement to cater for spinning. I find excessive expo difficult to cope with and so I use 3 rates to cover a Spin condition, landing and normal aerobatic flying. It works for me. It is also a function of how accurately you aim to fly. Obviously, in F3A, accuracy is paramount but it also depends hugely on the design of the aircraft. Some designs have no cross coupling in knife edge while others will need some mixes to stop unwanted pitching or rolling. There is nothing to stop you controlling those by yourself but you must also be able to fly the manoeuvre that incorporated the KE accurately as well e.g a rolling loop. However, the single most powerful method of taming a twitchy model is to move the CG forward till it become less sensitive - reducing control throws and using expo, if needed, also help but get the CG wrong and low throws will not cure twitchy aircraft. I believe it was Doug Spreng (of Sprengbrook) who said "soft sticks sell transmitters, hard sticks win competitions" - perhaps his views are worth considering.

You might be interested in reading the latest communication from the FAI and Europe Air Sports to EASA which has been drafted by Dave Phipps the Chief Executive of the BMFA - see here.

It takes 2 to tango BEB.

Posted by Biggles' Elder Brother - Moderator on 20/11/2016 09:55:43: Posted by Colin Leighfield on 20/11/2016 08:52:51: There's clearly a lot of background spadework been going on here. Unity is what it's all about from the influence point of view, top marks to BMFA for the way they have handled this so far. Mmm,....well personally I thnk FAI and EAS, along with DMFV (Deutsche ModellFlieger Verband, the German equivalent of BMFA), had rather more to do with it! Indeed DMFV's response was in my view a model of how it should be done, balanced, tightly argued, and well informed. In contrast what we got from BMFA was the ridiculous "We're all doomed" headline from Phipps which did little more than trigger a load of deeply unhelpful xenophonic emails. I was, and remain, not impressed. BEB Edited By Biggles' Elder Brother - Moderator on 20/11/2016 09:56:33 BEB - you may not know this but Dave Phipps drafted the responses for EAS and the FAI and has been invited to brief EASA further this Monday. I think that you have both taken the thread off the original OP and have done Dave a grave injustice. You have made it quite clear in a number of posts that you are anti BMFA. So be it. But please do give credit where credit is due or, if that's too much, then please don't run down Dave Phipps when his actions have been widely accepted and adopted by EAS and the FAI. If some people have been xenophobic it is not Dave's fault. The last time I checked, it is a free country and you can express your views freely so don't blame the Dave for the way others have reacted.

John you have to roll in both directions for the B anyway. I think it's immaterial whether you roll towards or away from the pilot's position for the reason MattyB has stated. Why would an Examiner ask you to do something that is not in specified in the Guidance Notes for Examiners? Perhaps because some have not read them?

Posted by Tom Sharp 2 on 10/11/2016 19:35:20: Doing two rolls, do you perform the two rolls as one manuover ? easy. Or do you pause at the centre before performing the second maneuver? harder Hi Tom, have you read the Guidance Notes for Examiners (and therefore Candidates) for the B? If not, you might like to download them from the BMFA website here. While there is specific guidance on which way to carry out the stall turn, there is nothing about which way you should roll. Some years ago I read that full size display pilots always rolled towards the crowd as the aircraft presented better that way. That was the way I rolled for my B and neither examiner objected. I'm with Matty B on this one. You can go wrong just as easily whichever way you roll. If the Guidance Notes for Examiners is silent on which way you roll that's what you take. Anything else is second guessing what the text says and is down, IMHO, to your own personal view. Judging the B should not be down to your own personal view but rather the result of careful reading of the Guidance Notes and attending a workshop to see what the required standard is in flying.

Thanks Martyn. I'very had one reply from a commercial outlet telling me the engine is not suitable for the tuned pipe treatment and from another that their 140 glow pipe would be suitable! My other solution is to find an airframe that is a lot lighter than the Capiche which tips the scales at 6.75Kg without fuel. Something around 5.5 Kg would obviate the need for more power albeit at greater outlay than a tuned pipe but with a higher chance of success - maybe😕

One thing to remember Paul is that trimming is an essential part of sorting out an aerobatic airframe - actually, any airframe! The single most powerful trimming tool is the CG position. For the Angel, having to exert a small push on the elevator when inverted is about right. As you won't have any adjustable incidence on the Angel the only other solution is to resort to mixing to get, for example, a true vertical down line hands off. Mix a small amount of elevator, usually down, with fully closed throttle. Make sure that you adjust motor thrust line to give as true a vertical climb as possible and the up/down thrust to eliminate any nose up/down pitching with application of power.

My AGM 30, my first petrol engine, has been excellent. I used a servo to operate the choke and mixed it with the throttle so that when you switch the choke on the throttle opened sufficiently to allow the choke lever to operate without let or hindrance from the throttle. Also, as I have a 3 position switch, I can get half choke and full choke. Useful when starting a not quite cold engine. Set half choke, apply starter, and when the engine is running, switch out the choke. The engine is in a Sbach 342 from HK and tips the scales at 5.2 Kg. The AGM endows it with unlimited vertical performance. I also have a canister silencer that is a snug fit in the Sbach fuselage tunnel. I've not checked the sound level but when it's flying it doesn't sound as noisy as some of the 50 glows.

Thanks John. Those pipes look expensive!

Hi Guys Is anyone using a pipe on a DLE 35 RA? If yes, what sort and what is the critical length to be observed? Thanks.

It is an Act of Parliament JS 50 that controls the use of the airspace in the UK.

Firstly, I never charge a LiPo without using the balance function - without that you run the risk of overcharging one or more cells and undercharging others. If you have a balance charger use it in balance mode and if you don't have a balance charger then it's in your own interests to get one! I charge 2 x 5S 5000 packs in parallel and with a Fast Charge to 95% capacity at 1C they are done in less than an hour. If I go for a 100% charge it takes about 10 to 15 mins longer. If it's taking 2-3 hours to fully charge then you have a problem with the charger or battery or both.

Adrian It all depends on the kv of the motor. If you have a motor with a kv much below 500 then go for the 6S. If you have a motor with a kv or say 550 then a 5S will do the job. A 5S with a 480 kv will not give you the sort of vertical performance that you need in the Mythos. The difference in my Monolog 70 was that I could fly the FAI schedule with a 6S pack but struggled with flying large manoeuvres with the 5S pack. Currently, I'm using 5S packs with a 550 kv motor but, while adequate, it does not give the consistent power of a 6S driving the lower kv motor. In an aerobatic aircraft there is no substitute for power. You can always use part throttle if you end up with too much thrust but not vice versa - believe me, an slightly underpowered aerobatic aircraft is not nice to fly!