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GoldwingRc 91" Slick540 60cc Observations


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In the end I decided rather than do the simple jobs first I would tackle to one job I find a challenge and that is drilling out the prop bolt holes and spinner holes.

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First I decided to carve the spinner for the prop. The spinner is a 4" job, but the slots are too small for the prop I have in mind. First task is to tape up the area which will need to be Dremmelled out.

 

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In the end I needed to carve out more than I allowed for, but at least that job is done. I checked this by loose fitting the spinner without screws.

 

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Next job is to drill out the bolt holes through the propellor. I used the motor face plate as the template.

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I now had to line up the spinner's alloy backplate. Easier said than done as this had to be precise as the spinner 's 4 screws had to line up with the backplate too.

 

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After much fiddling about this was achieved to my satisfaction. 

 

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A drill press is essential for doing this job.

 

 

The assembly will all have to come off again for me to thread lock the standoff bolts and the fit the cowl and reinstate the prop and spinner. That's for another day.

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I had a couple of hours to kill this morning up the work shop therefore I thread locked the stand off/ motor bolts and refitted the cowl and prop.

 

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Next I fitted the cockpit hatch. The fit is average I would say as the mouldings don't quite line up, but nothing major nevertheless.

 

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I did have file out slightly the mounting hatch holes for the fuselage bolts, but all easily done. 

 

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I just had time to do some work on the "office".

I gave a second chance to the flashy looking pilot who crashed my EF Extra SC. I decided to rename him Douglas because like his namesake he doesn't have legs either! 😂

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I found a piece of light ply that I cut to shape and drilled out the two fitting holes and used 5 minute epoxy to glue him to the canopy frame.

 

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Just a few small jobs left such as the U/C wheels/spats and fine tuning the working surfaces. There is guidance for deflections, but  I will have to give some thought to deflections for first flights.

Low rates for elevators 15 degrees high rate 45-50 degrees

Low rate for rudder 25 degrees high rate 40-45 degrees

Low rate for ailerons 25 degrees high rate 35-40 degrees

 

CoG  is noted to be 145-163mm behind the leading edge from the root. (5.7"-6.4")

 

I have wired up my watt meter such that I can fit it inline on the powertrain to see what the motor is drawing.

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The U/C leg collars are the best moulding I have seen in a while and fit the contour of the fuselage accurately.

 

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I did need to file one of the lowers slots slightly to allow it to slide up the leg.

First issue. My clear silicone sealant which I normally use to secure the collars had dried up therefore off the the shop tomorrow I guess so I can finished that part.

The other problem that has arisen is the wheel axles, which are sturdy, and their lock nuts fitting. While the axle lock nuts are threaded on the axle in the normal way, the nut on the wheel side of the axle is also threaded ....... Which means when I try to tighten the lock nut it unscrews in a counter intuitive way even trying to hold it with a spanner. Most of my axles on previous planes have the wheel side nut is soldered on such that it is a simple job just to screw on the lock nut the the other side. Not sure what I am going to do to solve this problem as I only have electrical connector solder on the bench. I guess to do the job properly it needs to be silver soldered. I did think I might glue the nut but I am not sure that would work. Any suggestions woulds be most welcome. 

 

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The red thread lock did the trick after leaving it to dry for 24 hours. Wheel axles secured and it was a simple job to align the collets with the wheels such that they don't scrape on the spats.

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The clear silicone was applied to the U/C collars to secure them. The final look of the U/C looks pretty good.

 

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Probably the next job will be to fix the initial CoG using the internal layout of lipos, RX and switches/connectors. I will report back with a posting on another day.

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One quick modification before I sort out the CoG. Now the kit comes supplied with nylon type M6 wing bolts which to my mind for a plane of this size is not appropriate. I have had experience down the field that after a while the threads cease to tighten meaning I have to go back to the work shop to find steel bolts anyway. I know the nylon bolts are supposed to minimise wing damage in a crash, but I find after years on practise I very rarely have that sort of crash so steel bolts it is then.

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In this instance I am using 30mm M6 steel bolts with a couple of washers. The same size as all my other 60cc size aircraft.

 

 

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On to the CoG. the manual states CoG for first flights should be 145-163 mm from the wing edge at the root.

 

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Given I usually balance my aircraft on the wing spar this appears to be at the rearward most point initially. Well I will go with that for the moment.

 

She is then hitched up on my crude CoG cradle. The batteries place are back right up against the spar housing. The lightest lipos are 2 x 5800 mAh 6s Overlander which are 800g apiece, while the RX 2S lipo is further back in front of the rudder servo. This initial position balances the plane at a slight nose down attitude. A bit more than what I was aiming for, but it's a safe start.

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Edited by Adrian Smith 1
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My other lipos are near 860g each which are 4-Max 6000 mAh and Nano-Tech 5000 mAh ( those Turnigy ones are heavy man!) They should help the balancing nevertheless. The reason why we are a bit nose heavy still is because the motor is designed for an 80cc+ and above equivalent leccy. Anyway I am not about to add tail weight at this stage until I see how she flies. Next job will be the wing surfaces throws. That be a whole afternoon job I think! 

 

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Then I hit two snags. One of the fuselage cross braces snapped in three places while working on the equipment position ( crikey! that bit is rather flimsy!!). I decided to add a a balsa support prop to stop that happening again.

 

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On to the elevator EPA adjustments. I decided for first flights to dial in 20 degs +/-. Higher than the 15 degs low rates and lower than the 45 degrees high rates noted in the manual.

 

In the process I hit a problem in that the rudder horns at neutral foul on the elevator inner edges on down elevator even at low rates. 

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What a pain. I think I will alter the rudder horn geometry and shave to slice off the horn edges to solve that issue.

I should have time on the next work shop visit. 

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It would have to be in two very thin strips, Ron. It's not obvious from the photo, but on the underneath of the cross brace there is a thin strip at 90 degrees to the brace making a T-shape. There is a similar cross brace a bit further forward above the wing tube that you can see in the first photo. I might be worth trying to do something with C/F strips there too as I did think the lite ply I have probably wouldn't do the  job. I just wondered if the narrow C/F strips might be too small to be of any use for strength. I can only give it a try. Failing that I have some hard wood square stringers I can cut to length and use that by gluing against the T-Joint underneath . Not much of a weight penalty therefore might be worth considering.  

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