Weston UK Capiche 50cc Revisited

[Adrian Smith 1]

Same process for the throttle lead on the other side encased in protective tubing.

 

 

Next I removed the choke and throttle servo cut out pillars and refitted the lipos.

 

All good. Next I tested the motor again without the prop and all was well thankfully. Back on with the cowl and with me being a happy bunny.

Really now I am not too far from thinking about the maiden. The only things left to do are to drill out the spinner base plate to accommodate the prop driver bolts re-check the CoG and if necessary slightly reduce the elevator throws if she is still a bit tail heavy. 

[Adrian Smith 1]

In a navel gazing moment I thought I would compare the weights of the recommended 50 cc petrol engine (DLE/DA) including ignition & muffler and my electric motor set up.

The petrol package weighs around 54 oz, which is what the Capiche was designed for,  while my Dualsky 50 cc electric equivalent motor is 35 oz before ESC which is strapped under the motor box.  I am not sure of the ESC weight (I will check it) , but it easy easy to see why I am having to load as much weight to the front as possible to get anywhere near the correct CoG........ That said I still think she is a good subject for electrification.

[Adrian Smith 1]

The Hobbywing ESC 160 HV OPTO I have weighs around 10 oz, and whilst not particularly scientific, leaves me with nearly 10 oz of shortfall in the comparative power plants. 

[Peter Jenkins]

Hi Adrian

 

Even on my all electric 2 m, I left the final position of the flight pack strapped to the battery tray as the last items to position to get the CG in the desired place.  The combined weight is 1.2 Kg so that's a pretty large weight to move around.  

 

Following the first few flights, I found the best CG position was 5 mm further aft and that necessitated moving the pack 70 mm aft!  Luckily, with the setup I was using it only required 4 new ply supports that the bsttery tray sits in a new position.  Unfortunately, when converting an IC engine design the best flight pack position is rsrely easy to reach but by using a sliding and locking mechanism might help.  See my Anthem build for a photo of the arrangement.

[Adrian Smith 1]

Thanks, Peter. My flight packs of choice (5.8A 6s x2) and weigh around 1.6kg. The one piece of latitude I have is the space to move them further back as the extended platform goes aft by some way. I know when I did my initial CoG check with the internals roughly in place I required another 4oz of weight within the motor box. whether this is the case will be seen when I do the final check. I am sure, given the nature of the model I will be able to get away with a rearward CoG as long as it not too much. As you say flight testing will reveal all! I will see if I can find you Anthem build on here to view your arrangement.

[Peter Jenkins]

I see you found the Anthem thread just before I posted it's location!  The bottom of page 1 and top of page 2 shows the battery tray.  Having assembled the model completely, I placed the the bits that were floating around into the fuselage and then used the complete flight pack and tray to get the CG where I wanted to start with.  That gave the battery tray position.  Subsequently, when I had to the batteries hanging off the back end of the tray(!)  I measured where they had ended up and moved the battery tray supports to go under the batteries completely.  I moved the tray about 70 mm aft IIRC.  

[Adrian Smith 1]

I managed to spend a little time in the work shop ostensibly to make sure everything is battened down ready for storm Ciaran. I did have time to drill out the spinner back plate and fit the prop. 24x8 is my starting point.

 

 

 

 

I had to replace the spinner M5 bolt for a longer one which in this case was a 55mm length one. 

I have a 23x12 on the bench that the hub needs drilling out. Thank goodness for having a drill press - what a great piece of kit that is. 

When the storm had passed us by, hopefully I will be able make the final adjustments/checks and report back before the maiden.

 

[Adrian Smith 1]

One footnote to finishing the assembly. I drilled out my other test prop this morning. As it's 23x12 the prop hub is understandably somewhat deeper than my "go to" 23x8. This means the prop driver bolts which come with motor are not long enough for safety at 45mm M5. In my bolts spares box I found four 55mm M5 bolts which fit the bill and will be used when I change the props. 

 

I will also have take a bit more off the spinner cone where the prop fits. 

 

[Adrian Smith 1]

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 .........

 

Edited November 13, 2023 by Adrian Smith 1

[Peter Jenkins]

Good luck with the maiden Adrian. 

[Adrian Smith 1]

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.

 

 

[Adrian Smith 1]

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 ........

[Peter Jenkins]

Well done Adrian!

 

On my little Capiche, I drew a centre line on the wing root rig and used a straight edge along that line to line up the ailerons.

[Adrian Smith 1]

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

[Adrian Smith 1]

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. 

[Adrian Smith 1]

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. 

[Peter Jenkins]

Hi Adrian

 

I hope you have along bar on that Robart Incidence meter!  If not, you will have to take the incidence reading at around half span.  I cannot reach the wing root with my Robart Incidence Meter so need to have the radio on and the control surfaces will then be able to support the weight of the meter.

 

I've usually adjusted the fuselage so that the tail plane is at 0 deg and then you just need to measure the wing incidence.  It is the relationship between the tail plane and wing that needs measuring.  Also, I seem to get very slightly different readings from my Robart meter when it is facing in the other direction so I tend to do all the measurements from TP to wing looking one way and then do the other side.  Of course, you want the TP to be the same incidence both sides so that's best done with the meter facing the same way.  I have resorted to photographing the meter if I cannot get my head in the correct position!

 

Without an incidence adjustment gizmo, all you can do at this stage is to record the built in incidences and use the ailerons to get the aircraft to fly level. With my set up, I tweak one wing's incidence to get the ailerons mechanically zeroed and then adjust the turnbuckle to get the servo to zero sub-trim and the aileron at mechanical zero.  That way, both the servo and aileron are at mechanical zero.

 

Finally, if you can measure control deflections by angle throw, it's a lot easier than trying to measure control deflection by mm of deflection at the root or tip.  It is easier to compare with other setups as well as the angle measured is independent of the length of the control surface.

 

Hope that helps.

 

Peter

[Peter Jenkins]

Forgot to post a photo of my throw meter.  I got this from Amazon.  You could probably make your own with a giant clothes peg and a few other bits!

 

[Adrian Smith 1]

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.  

[Peter Jenkins]

I'm surprised your throw meter weight affects the control surface resting position.  Mine doesn't I have to say.

 

I should have said the markings on my throw meter are in degrees, so the meter is showing 4.5 degrees of up elevator in this case.  Interestingly, this is my Wot 4 and with that total movement, both ways, I can fly the full fixed wing B test, apart from the spin.  The loop and bunt are a bit bigger of course!

[GrumpyGnome]

It's interesting to see the amount of effort you put in to get a 'true' flying plane.

[Adrian Smith 1]

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.

 

Edited November 27, 2023 by Adrian Smith 1

[Adrian Smith 1]

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.

 

 

 

Edited November 27, 2023 by Adrian Smith 1

[Adrian Smith 1]

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.

[Peter Jenkins]

Good work Adrian.  This is where an adjustable incidence comes in as you could set both wings to the same incidence. 

 

I have found that my Robart gauge reads slightly differently when its rotated to face outwards on both wings.  Having it face inwards makes it difficult to read so I resorted to photographing the readings using my phone.  Turned out to be the same incidence on both wings!  Worth a try to see if the machined slot in the bar is outside tolerance before making any other adjustments.