Ron Gray Posted January 12, 2023 Share Posted January 12, 2023 No problem Adrian, I enjoy your builds, cheaper than me buying one! 1 Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 13, 2023 Author Share Posted January 13, 2023 Ok so let's sort the rudder out. A job for the trusty Dremel. I moved the coupler to the next hole in as the outer hole is rendered unusable. At least there is now clearance on down elevator. interestingly, the manual shows a two hole horn rather than the three hole horn that was provided with the kit. Next I had to alter the position of the cable couplers on the servo horn to correct the geometry. The final adjustment was set at 30 degrees +/-(no expo)compared to the 45 degrees "hooligan" setting. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 13, 2023 Author Share Posted January 13, 2023 I take the belt and braces approach and put a dab of red paint on the couplers as an early warning against any unscrewing. I am always a bit suspicious of plastic threads against metal ones. Next job will be to set up the ailerons. 1 Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted January 13, 2023 Share Posted January 13, 2023 Nice tip with the thread paint, on a positive note I've never seen one of those ball links fail, sturdy items. 1 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted January 13, 2023 Share Posted January 13, 2023 Plastic (nylon) on metal, that’s what a Nyloc is! But I guess you’re more concerned about it pulling out. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 13, 2023 Author Share Posted January 13, 2023 Yes, Ron given the pull force of rudder wires when throwing the plane about. I tend to replace Nyloc nuts with normal nuts plus thread lock where possible but I accept it's not always the case although I agree Nyloc nuts have their place in our hobby for some applications. I must admit, John that I have never had a failure yet, but I follow the adage of my fictional hero Jack Reacher when he says "plan for the worst, but hope for the best" ! I am now a lone flyer these days and I can't afford to take risks. Quote Link to comment Share on other sites More sharing options...
Jason Channing Posted January 14, 2023 Share Posted January 14, 2023 (edited) The only other trouble with moving the horn inwards is that it creates an offset which you now really need to be using a cranked servo arm to keep the wires under tension once the servo has moved from it centre position, in normal forward flight it's not so much an issue but if you do tumbling manoeuvres and high alpha and especially prop hanging I would be surprised that you dont get blow back, Which is why these days on these models they mostly gone back to direct linkage, you can check this by moving the servo to your desired position and the other side of the closed loop should remain taught, but with an offset I doubt it will be. Edited January 14, 2023 by Jason Channing Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted January 14, 2023 Share Posted January 14, 2023 16 hours ago, Adrian Smith 1 said: Next I had to alter the position of the cable couplers on the servo horn to correct the geometry @Jason Channinggood point but I think Adrian’s dealt with it, judging by his comment above. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 14, 2023 Author Share Posted January 14, 2023 In my defence I rarely if ever do high alpha manoeuvres ( it's an age thing). Rather its standard pattern flying aeros and after some infrequent sessions due to winter weather I probably need the practice! Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 14, 2023 Author Share Posted January 14, 2023 There is the option in the rear fuselage for a direct drive servo for the rudder if needs be. But I must admit I have never experienced any blow back that Jason mentions. ( Always a first time I know). ✈️ Quote Link to comment Share on other sites More sharing options...
Christopher Wolfe Posted January 14, 2023 Share Posted January 14, 2023 I have always found that with a closed loop cable operated control surface the distance between the cable holes in the control horns and the distance between the holes in the operating arms must be equal and thus make a parallelogram (to avoid a slack line). One solution that I have used with success is to use an intermediate transfer arm with a pair of holes spaced to match the control surface horns and multiple spare holes to attach a link from a servo. I usually select fiberglass pcb material for this and include a decent bearing in the pivot. A strong and well anchored cross member is required to hold the transfer arm as it has to take flight loads from the rudder. Chris Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 14, 2023 Share Posted January 14, 2023 Chris's method also has the advantage of not subjecting the servo bearings to the tension in the pull-pull wires. The pushrod connection to the intermediate transfer arm just has to take the flight loads. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 14, 2023 Author Share Posted January 14, 2023 As Chris indicates the first priority in a cable operated rudder is to have the wires in a parallelogram, something that I have achieved by making the couplers at both ends (Rudder/servo) equidistant on the horns or at least close to it. I tend to have a reasonably applied tension on the wires given that in warm weather a slight slackening can be observed. The transfer arm Chris suggests is well worth considering depending on the type of flying undertaken or the quality and stalling power of the servo involved. For this type of aircraft I wouldn't consider anything less than a digital, metal bearing servo with an excess of 35 kg/cm at 7.2 volts. In this case I have found the Macgregor servos bullet proof in all my large scale aerobats. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 20, 2023 Author Share Posted January 20, 2023 Final bit of adjustment today with the ailerons being set with an EPA of 25 degrees +/-. That is a low rate adjustment according to the manual. If I want any more the servo geometry will need changing as the TX EPA shows 100% based on that measurement. Seems quite generous already to my eye. Anyway we will see. There is no expo at this stage until the flight envelope has been tested. One other observation is that while the main C/F wing tube fits through the fuselage nicely, the fit of the wings themselves on the tube are quite tight. I will have to be careful on assembly due to balsa and ply and all that entails. I am not using the side force generators at the moment, but I have not discounted them. All that remains is for a decent day without freezing temperatures to conduct the maiden. I will post a clip when the deed is done. 1 Quote Link to comment Share on other sites More sharing options...
Ron Gray Posted January 20, 2023 Share Posted January 20, 2023 I would be inclined to go over the tube, the portion that fits in the wing, with a very fine sandpaper (watch out for c/f dust 😷), clean then apply furniture polish. 1 Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 20, 2023 Author Share Posted January 20, 2023 Yes, Ron I think may be I should give it a go. I think I have some Beeswax furniture polish hiding somewhere ...... Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 20, 2023 Share Posted January 20, 2023 3 hours ago, Adrian Smith 1 said: Final bit of adjustment today with the ailerons being set with an EPA of 25 degrees +/-. That is a low rate adjustment according to the manual. If I want any more the servo geometry will need changing as the TX EPA shows 100% based on that measurement. Seems quite generous already to my eye. Anyway we will see. There is no expo at this stage until the flight envelope has been tested. One other observation is that while the main C/F wing tube fits through the fuselage nicely, the fit of the wings themselves on the tube are quite tight. I will have to be careful on assembly due to balsa and ply and all that entails. I am not using the side force generators at the moment, but I have not discounted them. All that remains is for a decent day without freezing temperatures to conduct the maiden. I will post a clip when the deed is done. Wow, +/- 25 degrees for ailerons for low rates for flying precision aeros and not 3D! I suspect the ailerons are quite big to start with for 3D work. I use +/- 10 degs on my ailerons on my 2 mtr F3A airframe for low rates with max rates giving around 20 degs. I also use between 20%-35% expo to get the balance between making very small adjustments in flight that I want to be unnoticeable to judges and to balance against crisp rolling for full and part rolls. Still, it's your call. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 20, 2023 Author Share Posted January 20, 2023 Yes, Peter it sounds a bit excessive. High rate ailerons are 35-40 degrees in the manual!! The ailerons are pretty big as you suspect, but I think I will moderate the low rate setting by 10 degrees to say 15 degrees and see what happens. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted January 28, 2023 Author Share Posted January 28, 2023 Just a final thought before the maiden. The kit doesn't come with wing bags like some (not surprising given the price of the kit). Therefore I set about sourcing some at a reasonable price. Well Leeds MS come up trumps with these at £38 which are 600mm x 1500 mm and fit the wings perfectly. I suspect they are for gliders, but it matters not as they are a good fit. I did fly my Pilot RC 67" Slick today for a bit a pre maiden practice as she is a bit tricky and lively so it should stand me in good stead. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted February 6, 2023 Author Share Posted February 6, 2023 (edited) Today seemed like a good day to maiden the GW Slick. I would I have liked a bit more wind but, Hey, can't have it all. The morning didn't start out very well purely because the motor wasn't rotating in the right sense. I really thought I had previously checked that, but obviously not. Therefore off comes the spinner, prop and cowl so I could reverse two of the motor wires. I would have to dismantle the front end too with the programming box anyway, but as I had left it in the work shop this method had to suffice. Checked again without the prop of course and all fine so I put the cowl and prop back on. Delayed me by about 40 minutes. Nice sunshine anyway! A couple glamour shots before we start, As it turned out the maiden wasn't as relaxed as I had hoped because on the first flight it was clear she was more nose heavy than I realised and a fair amount of up elevator was required for straight and level flight. The TX tells the story. Rudder fine and a small amount of left aileron with the elevators quite a few clicks. After trimming she flies well with knife edge quite steady. Rolls very slick and un scale like (less EPA needed I guess). The stall turn is a bit laboured on the turnover, but more rudder throw will help as with a bit more power. More on that later. Here is short video clip of the second flight which is nothing special while I examine the flight envelope, but she lands like a dream, however. https://youtu.be/wggb3GGxL3w Edited February 6, 2023 by Adrian Smith 1 Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted February 6, 2023 Author Share Posted February 6, 2023 What to do about the CoG? It's clear the power packs can't go back anymore as they are bang on the wing spar with nothing else behind to support them. I could use the extra weight from 2x 7S lipos (rather than 2 x 6S) for more power as this is within the motor specification. At least then it would be "useful weight". That would require a new charger which will cater for 7S lipos as mine only are good for up to 6S. Any recommendations for this charger by any chance as there aren't many on the market? It would give me more power too. Food for thought here and more financial outlay I guess, as I don't have 7S lipos either. I don't really want to put dead weight on the rear of the plane using the current set up as it will just detract from the performance. Hmmmm ...... Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted February 6, 2023 Share Posted February 6, 2023 You could try using sticky lead weights at the extreme rear of the fuselage or the under surface of the tail plane to see how much weight was needed back there to get the CG to the sweet spot. Then you can decide how far back you need to move the main pack. As I don't know how bit a problem is with moving the drive pack aft could you put a picture up to show the problem? Quote Link to comment Share on other sites More sharing options...
john stones 1 - Moderator Posted February 6, 2023 Share Posted February 6, 2023 Weight to trim it to your taste is useful weight, wouldn't hesitate to use some stick ons on the tail end myself, bit of thought and you'll not see them, nice job Adrian. 👍 Quote Link to comment Share on other sites More sharing options...
Philip Lewis 3 Posted February 6, 2023 Share Posted February 6, 2023 Certainly wouldn't be going over to 14 cell using two 7 cell packs, I don't think that you need to do that, it would be expensive as well and made worse as 7 cell lipo's are pretty rare let alone that as you say you will need new chargers to charge themm. That would also only make the C of G even more of a problem. I would up the prop size first, this motor is way more than capable of flying tht plane, persoanlly I would pick a known brand as well just to make sure the prop was efficient. Peters suggestion is spot on, even if you don't use it you will then know how far out you are, but is it really nose heavy? You said it flew knife edge steady but was it straight without any down elevator input? A nose heavy plane should be pulling quite hard to the canopy, what does it do on a 45 deg upline if flipped to inverted? These do land like big pusycats though don't they. Quote Link to comment Share on other sites More sharing options...
Adrian Smith 1 Posted February 6, 2023 Author Share Posted February 6, 2023 (edited) Hi Peter. Photo show the issue. The space behind the wing tube is at a different level and won't accommodate the power packs' size either. I did think I would transfer the RX and switch to the front of the tube but the lower deck level is not big enough even if I added a false deck for the power packs to be put there. Behind the rudder servo is not an option because of the cables. I might have take another look at the area behind the wing tube though. John. Thanks. I may have to look at stick on weights as you say. My only concern particularly with electric is to try and keep things as light as possible without adding weight that is just there for weight if you follow me. Philip, I only tried knife edge after introducing up trim on the elevator so to all intents and purposes it looked to perform as I would expect for knife edge after that. I did notice that before I trimmed the elevator, inverted flight saw the nose drop which I thought confirmed nose heavy. The 2 x 6000 mAh 6s packs I am using give enough power and duration for me on the prop I am using therefore that would be the last option to change to another prop although I wouldn't rule it out. The prop is a 26x10 which is the recommended mid range by Dualsky for this motor. Edited February 6, 2023 by Adrian Smith 1 Quote Link to comment Share on other sites More sharing options...
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