Peter Jenkins

Posted by Peter Russell 3 on 06/12/2018 15:58:19: Hi I have a DX6 and want to get the servos to go 180 deg not 90 Any sugestions as to how to do it? Peter, what are you trying to achieve? You will get more focused answers if you tell us that.

OG, you might find following this trim process helpful. Your description of your aircraft's behaviour points towards a CG that is too far forward but as already mentioned it could also be the thrustline is out. The process I've linked you to deals with how to sort out the thrustline both for pitching and yawing issues. Be interested to hear how you get on.

Cymaz - you beat me to it. As those who follow the link will find out, CG position is the single most powerful trimming tool available to us. Setting the CG to the quoted figure is merely the starting point of trimming. There are many reasons why the "quoted" CG position may not be right for that particular airframe apart from the position given being incorrect. You can only really identify the correct CG position for that particular model when you fly it and the trimming guide gives an excellent way of finding what is that position. The second most neglected area, IMHO, is adjusting the engine/motor side and down thrust. Again, the guide tells you how to fix these issues. While many sport flyers may find the rest of the trimming guidance not worth the effort, failure to do so becomes an issue if you are flying an aerobatic airframe and wish to fly aerobatics to a good standard. However, all the advice applies equally to any aeroplane and if followed you will end up with a very nice flying aeroplane with no nasty vices unless they are an intrinsic part of the design and, the fact that if it is a scale aircraft, the scale factor or Reynolds number. Suffice to say that at the the Reynolds number we fly our average Club aircraft, perhaps half of the aerofoil (wing, tailplane or fin/rudder) are not contributing anything other than drag past their maximum thickness point. That's why scale models either have rather bad flying characteristics or else have a larger tailplane than scale to address this issue. Finally, to pick up on an earlier point of matching servo throw to the desired control surface deflection, do remember to zero the sub trim and mechanically set the servo arm as close as you can get to the 90 deg to servo edge before using the sub trim to get that angle to 90 deg exactly. Winding in loads of sub trim can restrict the control movement in the direction that has been consumed by excessive sub trim. Martin - there is a great deal of work underlying the "gearing" of full size aircraft control movements. For non powered flying controls, the designer would use mass, spring and dampers n the control circuit and tabs on the controls to give the type of feel the test pilot felt appropriate. Today, of course, most of this is done in the flight control software. For example, current 5th generation fighters are flown by the flight computer with the pilot telling the computer via his control stick position or force (some sidesticks don't move!) how much force he wants generated. Pulling maximum G is down to the computer deciding what that is for any given aircraft configuration, weight and speed the pilot merely pulls as hard as he can and trusts to the computer to keep him safe. Of course, if the pull out he wants cannot be carried out before the earth intervenes then he flies into the ground under full control at maximum alpha!

+1 with GrahamWh. Whilst I often hear folk say you don't need expo and you can just use smaller rates that is true up to a point. If you want to fly accurately, and I mean accurately, you will need to temper the inbuilt expo as explained above with some expo to reduce sensitivity around the stick centre. I have not done the sums, but a very experienced aerobatic pilot wrote a trimming article where a 36% expo gives a linear relationship between stick and control surface position. I tried this and it works for me but I also have quite small movement on my aerobatic aircraft. A common misconception is that you need loads of movement and that aerobatic aircfraft are very twitchy - this is not true of course but encourages folk to set up far too much movement on their controls particularly for maiden flights rather than use different rates to cope with grossly out of trim aircraft on the first flight.

A member at one Club I'm at has introduced us to Teamup Calendars. Works really well. We used a email distribution list before and some members were unconvinced about the change. Fair to say that all are now very happy with this arrangement. I refuse to use Facebook but if that's what floats your boat that's OK. However, TeamUp gets over the problem of some on FB and some not. Worth a try and it's free.

Have you tried the wing bags from Hobby King? They are amazing value and can be hung up if you want. I made some wing bags with the radiator foil stuff and they are not as robust as the HK bags and have space for wing joiner tubes and, if you take them off, tail planes as well. £15 for a bag where it would cost £30 just to buy the zips in the UK is amazing value. Just my 2 pennorth!

I live out in the sticks and live on a C class unnamed road. My experiences have been that RM, DPD and Hermes are pretty darn good. Yodel is a bit variable though. I did send a high value parcel on a 24 hr guaranteed delivery with RM and it took 48 hrs to deliver. As they said the fee would be refunded if they missed the 24 hr target, I put in a claim and it was settled without delay or argument as they had the timings themselves. Perhaps I've been lucky but I suspect that you feel far more inclined to post a complaint than the vast majority who get their stuff delivered without a problem. I can understand the frustration when it occurs though!

Seems to be some confusion about the BPC for fixed wing model aircraft. The text below is a straight cut and paste from the current "Test Standards for Chief Examiners and Club Examiners and Guidance for Test Candidates for Fixed Wing Power (BPC, A and B)" page 5 Whether the candidate is awarded a Basic Proficiency or an 'A' cert depends entirely on what model they present for the test with;    If the candidate presents with a model that is not capable of taking off from the ground they will take the BPC If the candidate presents with a model that is under 1kg, they will take a BPC, (irrespective of whether it has electronic stabilisation or not). If they present with a model with electronic stabilisation, they will take a BPC (irrespective of mass). If they present with a model without electronic stabilisation, which is over 1kg and capable of taking off from the ground, they will take an 'A' test. Note the 3rd bullet point - irrespective of weight. So, in theory you could take the BPC with a 19.9 Kg model fitted with electronic stabilisation. Seriously though, the BPC is exactly the same as an A test but allows those whose model is below 1 Kg, or has no undercarriage, or has flight stabilisation (irrespective of mass) to take a test that is identical to the A test. The standard to pass is the same. BEB - cannot understand why your LA has said A test and won't accept the BPC. The two should be flown to the same standard and are identical. The real problem is akin to passing your driving test with an automatic and then wanting to drive a manual transmission car. Someone has to monitor this. So, Club Committees might take the view that it is easier to just say A test or nothing. It is up to Clubs to decide what they consider to be an adequate standard to fly unsupervised at their Club. The BMFA does not require an A to be held to fly unsupervised.

Never built anything without intending to fly it. An issue with spending a lot of time building is whether you also keep your flying current. If you don't then I can understand the reluctance to fly something that has taken a lot of your time to build when you are not confident of your flying skills. Best to brush up on your flying skills before flying the new build or else, as JS says, you end up with an ornament.

Adrian I've been using Zippy's for a few years and they are good. I started with Zippy Compacts but found that the Zipply Flite Max (the Compacts are the same but in a slightly different shape) are just as good and cheaper. Ah, slight problem, they don't list FlightMax at 6C only up to 5C. Peter Edited By Peter Jenkins on 23/10/2018 00:22:23

Posted by Bob Cotsford on 20/10/2018 09:16:43: This is made worse because we're concentrating on the elevator while also trying to add throttle and worrying about the ground so it's easy to allow the ailerons to wander. It can help to use a lower rate, trust the model, it will happily fly around an outside loop if you let it - provided it has power to pull it round or airspeed to carry it. Bob raises the interesting point of allowing the ailerons to wander. If you fly thumbs, then as you push the stick forward, the geometry of your right hand (assuming Mode 2) holding the Tx will result in the almost inevitable introduction of some right aileron. I cured this by moving my hand around to the base of the Tx so that as I pushed my thumb forward it just needed to go straight forward and not swing in an arc. The better solution for me was to transition to using a tray and learning to fly thumb and finger fashion. I have watched pilots fly thumbs who were unaware that they were moving the ailerons when the pushed the stick forward, or pulled the stick back for that matter. So, as suggested above, get someone to watch what you do having briefed them on what they should be looking for - inadvertent use of the aileron. It is amazing how much easier it becomes to fly a bunt or loop accurately. Most discussion about models screwing out of the loop/bunt, once you have eliminated problems with aircraft set up, are due to the introduction of aileron inadvertently. Since you don't know you are doing this it appears to be a model fault rather than what it really is, a pilot fault.

Posted by Tom Sharp 2 on 20/10/2018 01:16:42: People often have difficulty with this trick in that their planes are badly rigged The first requirement of this maneuver is a correctly aligned wing and tailplane.. The hinge line of the elevator must be exactly parallel to the trailing edge of the wing. With a tapered trailing edge wing suitable adjustments to the measurements will be made. Any divergence from this setup will induce a roll, easily and subconsciously corrected in normal flight, but not so easy in a semi stalled maneuver like a bunt. This causes the roll out in the climb back to level. Hi Tom, have to disagree that a bunt is a semi-stalled manoeuvre. Your entry speed should be your normal datum speed for level flight. Thereafter, the speed increases to a maximum at the bottom of the bunt and should return to the datum speed that you started the bunt with. Note: always provided that you are not trying to fly a bunt that is too big for the available engine power. If you are close to being semi-stalled then you are performing the bunt incorrectly. The bunt is the opposite to a loop and the loop is not a semi-stalled manoeuvre either. Any unwanted roll in either a bunt or a loop is easily corrected provided you have thought about the manoeuvre before you attempt it. Admittedly, the first time you fly a bunt this might not be the case but if you start a bunt, roll a small amount to the left and then correct with a small roll to the right you will find that it is not much more difficult than when rolling left and right in level flight. As Martin says above, don't make the manoeuvre too tight/small. Provided you have adequate power, you can fly a large bunt and that gives you time to observe what the aircraft is doing and apply a corrective control. The other point to remember as you bottom on the bunt with the engine now producing maximum power is that the elevator will be more effective than it has been due to the prop wash having been off for most of the time from the top of the bunt. So, if you hold the same elevator command, the bunt will tighten up due to the more powerful elevator force. To avoid this happening, you need to ease off the elevator as the power comes on so that the shape of the bunt is maintained and you end up at the top of the bunt at substantially the same height as when you started.

Couple of points to add. Firstly, ailerons work the same way whether the aircraft is upright or inverted - it's only the rudder and elevator that "appear" to work the wrong way. As you proceed around the bunt, or loop for that matter, always keep the wings level otherwise the aircraft will, as the saying goes, screw out of the loop. On the other hand, if you are looping cross wind, then you do want the aircraft to screw out of the loop in the direction from which the wind is blowing - that gives you a round loop which does not get blown downwind. Always bank towards the direction from which the wind is coming though. Secondly, if you end up with the aircraft snapping it's because you have too much elevator movement and you have managed to introduce aileron as well probably. If that's the case, then you probably have too much aileron and rudder movement too. I see many quite competent pilots flying with an awful lot of movement on the controls who have problems with aerobatic manoeuvres. You do not need a lot of movement to fly aerobatics of the sort required for the B test apart from the spin when you need to make sure the wing stays stalled. If you have someone who flies F3A style aeros take a look at their control movements - you will be surprised at how small they are.

Jon, you should be proud of the fact that your fleet has reached those ages. This means that a) you maintain them well and take your pre-flight checks seriously and b) that you can fly them well. My newest model is an Irvine Tutor, bought earlier this year as newly built because I'd always wanted one and a trainer is handy when giving friends a taster of flying models. The youngest of my other models is 2 years old and after that the oldest is probably 13 years old (Top Gun Bucker Jungmann). I do have a Gangster 75 in build - been going about 5 years and two other kits unstarted - one of which has been hanging around for almost 10 years (Taurus).

Thanks for your input guys, much appreciated.

I'm just about to start building this kit and noted that the plan shows an OS 120 FS for the four stroke option but all servos are clearly marked Futaba S148. That rather surprised me as I'd have thought the S148 might not have been man enough for a 120 four stroke powered model. What has been the experience of others with the 65" span TF P51 as regards servos?

They are both amazing stories. Sadly, there were no photos of these events - just recreations.

If you liked the story about the winged engineer accidentally flying a Lightning, you'll like this story about the RAF pilot who flew a Hunter between the spans of Tower Bridge in 1968. Just Google Hawker Hunter through Tower Bridge and you will find many write ups about it including an ITV interview with the pilot, Alan Pollock, in the recent past. I actually had this particular aircraft on my inventory in my first job in the RAF.

Peter (Christie) - I've heard that quote attributed to Doug Spreng! I started flying with a neck strap and thumbs. When I got into flying aerobatics I used to find that when I got tense I rotated the Tx towards me so that it became difficult to move my thumbs freely. I transitioned to a tray and flying finger and thumb. It took me 3 months to make the tranisition. Having read the Doug Spreng quote I dialled up the stick springs to max and, if I could find stronger springs, I would fit them. I find it is helpful to feel the stick's resistance when flying complex manoeuvres. Just what works for me of course.

A good landing starts with a good approach which in turn starts with a good circuit. So DD do you fly consistent circuits with turns in pretty much the same place at the same height and with height being reduced from the time you turn cross wind and maintaining that angle of descent with throttle while maintaining the model's attitude or speed with the elevator. I see many pilots who fly radically different circuits and end up either too high or too low and then run into trouble. So, I would encourage you to get into the habit of flying a set circuit pattern for the prevailing wind. On zero or low wind days you want to extend your downwind leg so that your cross wing leg allows you to use a shallow approach - i.e. the speed is not too high. Remember that if the aircraft has its nose down and you just use the throttle to manage the rate of descent the model cannot stall. On a high wind day you may need to turn off the downwind leg almost at the runway threshold as your into wind speed will be low. But, as has already been said, practice circuits and landings and you will get better. Flying a whole session with just circuits and bumps is very worthwhile and never boring as it is one of the most difficult things to do correctly all the time.

They are all metric Rocker. However, if the engine is new, the only allen keys you need are the ones to remove the rocker covers and check and adjust the valve clearances and these tools should be with the engine as they are supplied by Saito with the engine.

Why don't you ask Steve? Set out what you think is unnecessary spending and see what response you get. Vague comments aren't particularly helpful.

Hi BEB Thanks for pointing that out. I have used the servo slow function on my Eflite Sea Fury to get the u/c to retract more slowly and at slightly different speeds. I should have known better as by the middle of the war, most aircraft had much higher pressure hydraulic systems and u/cs tended to retract together at the same speed. Indeed, if you watch videos of Mustangs they don't have one leg going up and then the other - that was the preserve of the earlier marks of Spit and Hurri and other such aircraft. What I really wanted was a sequencer that made sure the door opened first, then the u/c operated, then the door closed. The HK sequencer does this at a reasonable cost. What I have asked of the JR programming guru on RCU is whether the XG Tx series has a similar function. I have yet to get a reply as he usually goes away and tries to see if he can get the software to function in the way in which I'd like. He gave me the way to get crow braking on my aerobatic biplane by swoping over one of the servo connections on one wing and, hey presto, crow braking with all ailerons moving to raise/lower the ailerons on the top/bottom wing respectively. Unfortunately, this reduced the roll rate and as I wanted to slow the aircraft on a vertical down line while doing a full roll, it got rather too close to the ground on occasion. The problem was solved by moving from a 2 blade to a 3 blade prop which gave much better braking on the down line allowing the crow braking to be dispensed with. BEB - you are right - the JR manual is reasonably easy to follow but is also a bit opaque, as most such books are, when it comes to telling you exactly how to do things. Many thanks to all who have contributed to pointing me in the right direction and for letting me know that my chosen solution does work fine.

Thanks Tom. I was going to do that for the tailwheel doors but I think the main doors might need something a bit more positive. I've been following up the link Ron provided and found this one as well. This provides four separate outputs - 2 to the gear and 2 to the gear doors. Sounds like just the thing I need so I ordered one and at £12.55 delivered from Hong Kong doesn't break the bank. It will be some time coming but as I haven't started the build yet that doesn't matter.

Hi BEB and Bob, I've got a JR XG11 Tx that has a lot of features but I don't recall one along these lines. It doesn't mean it won't have that feature just that I have not seen it in the handbook. Looks like I need to contact the guru on RCU on JR programming to see if he can figure out how it could be achieved.