Adrian Smith 1

A lot to take in there, Peter and I am most grateful for your help and explanation. You have put it all so succinctly that even I have followed the gist of it and it's clear. I did wonder if it was the positive TP incidence with the main wing at 0 deg that was causing my use of excessive elevator trim upwards, without of course knowing for sure why! (I know now! 😀) Poor choice of words to use "unstable" in relation to aerobatic flight and I acknowledge that and like your description. I am pretty sure the Slick CG is more rearward from the mid-point, but it doesn't bother me, but I will check for sure at the next workshop visit. Incidentally now I have an extended bar for my Robert meter I am going to go fully over the Capiche and measure all angles just to satisfy myself and report back on that particular thread. Thanks again 👍

Now I have bit of weather related work shop time, I decided to go over the Slick after about 3 hours flying time. First I regularised the servo arms to allow for the trim and neutralised the TX trims. I still have a fair bit of up elevator dialled in so I thought I would measure a few incidences. Firstly, the motor is exactly 0 degs to the datum line. In absence of guidance that seems fine. First the main wings. Both the port and starboard main wings are at 0 degs as good as damn it to the datum line. Now the odd thing is that the tail planes are both reading at +1.0 degs. They are fixed as per the ARTF build so I am puzzled why that should be. Indeed I am not sure what effect that would have in flight. I am sure there are a lot cleverer chaps here that can tell me. The last thing I am going to recheck is the CoG to satisfy myself she balances mid-range. I don't have too many worries there, as she is unstable enough for aerobatic flight but stable enough to control as normal.

Too much cold for my digits this morning sad to say, GG. 🥶

Great effort, GG. This weather the most difficult thing is to walk out the door. The rest is easy.🥶

Thank you, Philip I appreciate the time you have spent to outline your thoughts. My mantra is that you never stop learning (even after many years in this hobby) and your tuppence worth is worth pounds in value for the advice! 😀 The tip about aluminium strip from Wickes is a great one and there is a store not far from me. I have been convinced now that I should use expo more readily on my aircraft and as the throws on the Capiche are quite wide she will be an ideal test bed. Your info on the servo geometry and it effect is particularly interesting. Many thanks to you and Peter for your very helpful feedback 👍 I will report back after the next flights when the temperature outside rises a bit more above freezing.

Very interesting, Peter. As I tend employ more of a freestyle type of flying (not 3D) I probably can get away with larger EPAs. I take your point about active use of expo and I will add some too including on the rudder, probably not too dissimilar to the values you are using. 👍

Thanks, Peter I will try that. Something else I am considering is whether to add some EXPO. A couple of my aerobats have EXPO amounts dialled into the elevators and ailerons. There are no recommendations in the manual and I must admit I have never been truly convinced it helps me much. The amounts on my other aerobats range from -30 to -35 on the ailerons and -10 to -20 on the elevators. I have not added any to the rudder. These seem a reasonable starting level for the Capiche so I may well give that a go.

On to the elevators. Once again the trim was neutralised. Having done that I noticed the port elevator was not wholly in neutral position compared the the starboard side elevator. That might have contributed to minor roll out in some moves. Duly corrected. I then reset the elevators at 35 degs +/- which is once again intermediate setting. Both EPAs were slightly out by the way. Now the fun bit. The "mean" wing incidences were at 0 degs for both elevators. I did have a look at the rudder, but nothing untoward was found. Depending on how she flies next time I may reduce the weight in the nose from 4oz to 3oz as I am not convinced she needs all of it.

Just for a bit of fun I thought I would check the wing incidences. Now I know you are supposed to check both the wing root and wing tip, but the gauge is not big enough to check the wing root so I had to be satisfied with a "mean" reading. The starboard side was at 0 deg. while the port wing was +0.5deg. Obviously, because I could only take one reading per wing I couldn't see if there is any unintended washout built in.

I have had very productive morning in fine tuning the Capiche. I decided to make sure she was level along the datum line down the fuselage using a spirit level. As an assumption (which proved correct) that the centre line of the main wing F1 where the wing pegs sit is at 0 degs to where the fuselage is being levelled. I made sure that the two peg holes were the same distance from the cockpit shelf in both cases, in this instance 7 cms, before adding the spirit level. The first thing to do then was to ensure the ailerons were in the true neutral position. After cancelling the maiden trims it appears both port and starboard ailerons were around 1-2mm out. I corrected this with the gauge using the TX sub trims whilst making sure the rubber feet on the gauge were equidistant from the main wing trailing edge. Both port and starboard wings were done this way. The EPAs were also slightly out by a mm or two so I reset them from the TX at 25mm +/- which is the intermediate setting according to the manual.

Thanks, Peter. I also have throw meter on a peg which came with an Aeroworks Edge aircraft many moons ago. I just found the weight of it weighed on the aileron/elevators such that it wouldn't give me an accurate reading even with the radio on. The throw meter from Great planes just about does it's job given the size of the Capiche ailerons/elevators. I will look at that next week. Not tried the Robarts incidence incidence meter on the Capiche yet, but it will only be for my info if indeed the bar is long enough. The other side of the GP throw meter is marked in mm so it's easy enough to turn it round by loosening the screws.

Looking at the end point ranges. In my test flights the elevator which is set at 30mm +/- and rudder at 40 mm +/- seemed fine for early flight testing. However, the ailerons at +/- 20 mm didn't seem to be enough. I am going to increase the throw here to 30 +/- and see what happens. I dug out a couple of bits of kit to make sure the working surfaces precisely doing what I wanted using the radio's computer settings. Given that the main wings are a symmetrical pattern it will be a simple job to fit the throw gauge to the main wings with the rubber base block equidistant from the trailing edge. this should, hopefully, tell me accurately whether the full length ailerons are exactly in the neutral position to start with. I will probably do the same with the elevators and at the same time check up/down measurements of the throw limits. While I am at it I am going to check the wing incidences with this- There is no information on this being at ARTF, but at least I would like to know what they are by levelling the fuselage using a spirit level. More on that later. I am a bit dubious about changing too many variables at one time so I am thinking I may only change the propeller after this bit of testing. Incidentally I did run the motor without the prop after the programming box adjustments and noticed a big difference in motor rotation. I will also put my inline ammeter on to see how many amps I am pulling, although on the ground it will not tell the real position as to when the prop unwinds in the air.

Now to start on the serious fine tuning. First job is to go into the Hobbywing OPTO ESC with my programming box. I began with the timing setting. The available range is 0-30 degrees with 30 degrees being the highest. The ESC is still on the default setting of 15 degrees. I decided to adjust this upwards to 22 degrees. While this will increase the motor output somewhat there are two things to be aware of. Firstly, this will mean a reduction in duration (not sure how much until I test it) and will be accompanied by a slight whining noise at the higher throttle settings which is something I have encountered before. Clicking through the other fixed wing settings I decided to increase the start up force. The range is 1-7 with a default at 3. I increased this to 5. Those were the two things I chose to alter as they have a direct bearing on performance. Next on to the working surfaces.

Thanks, Peter. I think I will start there just to be sure before I look at everything else.

I know how you feel GG. It'll be gloves this weekend! 🥶

Nah, 50cc size powered electrically! 😀

Maidened my electric Capiche 50cc today. A bit cold and I had to watch my finger action as I could see the feeling beginning to suffer. see the link below. https://forums.modelflying.co.uk/index.php?/topic/52940-weston-uk-capiche-50cc-revisited/page/7/&tab=comments#comment-979816 At least I got her down safely after 3 flights 😅

DEBRIEF. First my impressions are that she is lacking forward power/speed. She has a tendency to roll out of an upright bunt while in the roll she has a habit of dropping out. Loops are fine, knife needs a bit more control than some of my other models but not too onerous and she almost flat spins upright so a bit of work there is needed. My first thought is to try a higher pitch prop and swap out the 24x8 to a 23x12 which I also have ready. The only trim needed to start with was 3 clicks of up elevator with nothing else touched. The motor ESC /combo/ power packs are the same as my other 50cc aerobat jobs although it must be noted she has quite a long body moment for her class (discovered when I tried to put her in my trailer!). I did wonder about the servos capacity/rating. My other 50 cc planes have Magregor 7232HV servos rated at 31kg where as the ones in the Capiche are MG5921HV which are 20kg at the highest voltage. Looking at the manual The aileron recommendations are for Hitec HS 5625MG which look completely inadequate at 9.4kg torque at the highest voltage! The two elevators are recommended at HS7955TG which rate at 24kg which is much better. I did find that the rudder servo screws needed tightening up as did the servo horn, but not a big deal. She also weather cocks quite strongly more so than my other 50cc aircraft. The other thing to check is the neutral alignment of the full length ailerons as I did this by eye which is not Ideal, so I am looking for a piece of kit that will do this for me accurately. The elevators are not full length and therefore easier to do. Much thought to be had, but at least something to get my teeth into ........

Well, the morning dawned for the maiden. A bit chilly, but at least the wind was about 4-6mph down the strip. I bit dull although the sun was threatening to show itself. Checklist for the pilot - bicycle clips .. tick, nuts and bolts checked ...tick, flappy bits all in the right sense .......tick. Off we go. https://youtu.be/41Xe18Ue2fU A short video of the maiden which I curtailed a bit due to shall be say her slightly wayward tendencies. You would have thought I would have mastered takeoff by now! Anyway I had two further flights and some attention is required. Debrief follows in the next post.

Looks like it, Peter. https://sussex-model-centre.co.uk/products/cml-extreme-40-51-2-st-53-91-4-st

The Capiche went back on the jig + batteries with the CoG template measuring at 230mm (225-240mm is the starting range). She balanced there with 4oz resting on the nose. Off came the prop and cowl to allow me to bolt the weight to the motor box. I did blue thread lock the nut, but it will be easy enough the remove/add a smaller weight after I have flown her. Back up on the rig. Just a tad nose down, but that will do for starters. All I need to do now is check all bolts and fixings for tightness .........

I started off on the Fly Boy. Two flights in and I crashed it irrevocably. I think it said more about my ability, or lack of it, rather than the plane itself!

Sounds good to me, Peter. In this case it might be best to leave well alone!

Yeah. I was out this morning and it was pretty cold although the wind was barely 5mph in Suffolk first thing. Better that the the infernal rain. 😃

Thanks, Peter. When I get a run of days in the work shop I am toying with the idea to check and see if there is some inadvertent down thrust in the motor which causes the need for up elevator trim. I am a bit dubious about it purely because when I close the throttle on finals there is no ballooning in fact she she keeps a nice line. I am not a one for tinkering too much, but it will be interesting to measure if there is any down thrust at all which I don't think should be present given the pure aerobatic nature of the plane (only side thrust) . As I have noted previously given the ARTF nature of the aircraft altering wing incidences is not a place I wish to go. Additionally, I have noted that the CoG if anything is a bit rearward. I am not going to stress about it too much as she is a treat to fly even given the trim dialled in.