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satinet

Shorten the servo wires as Mr blue bird kindly provides a 6foot length on each servo..... I crimp my own connectors.

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satinet

Potting the wing servo looms with e6000 goop. 

The model has a quite large ballast tube - if you do nothing the wiring loom will stop the wing joiner going through the hole.  Common problem - solution in this case - bits of foam. 

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satinet

Said ballast tube is nice but it means the back vtail pushrod wants to go round quite a sharp conner. As I am using small servos - bms107hv, I decided to move the pocket over a bit. 

I use screws from model fixings that have a hex head - miles better than the tiny little rubbish screws you get with servos that don't fit any screw driver in the known world.

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satinet

On to the tail - this model comes with a rod for each tail - this is similar to the tail on a skorpion or extreme, but is removable from both the fuselage and the tailess themselves.

I am not really in love with this arrangement type, but it is what it is. After having read a thread rc-network I decided to glue the rods in as I could not see a practical way of preventing wobble.  I also need to adjust the holes with a flat file as out of the box the tail was slightly out of alignment with the wings in the horizontal plane. On the bottom pic you can see a sliver of wood wedged in to keep the correct position while the glue dried. (Vtail angle is 98 degrees).

N.b I also glued inside a 3mm round carbon tube for a bit of extra strengthening.  The joiner was then sanded back to match the fuselage - a little over sanding, but it's okay...

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satinet

Now to the nose weight - you can't make a shaped block and glue it in in the traditional way here - near the end of the nose are small ridges where I assume the end of the balloon that was used in the layup ended or where part. of the layup ends.  (I've had this on other models).  Normally I would probably wet pour lead in anyway, but I don't have access to a blow torch or camping stove at the moment, I wasn't melting any lead anyway. I didn't think using the magnetic induction hob would go down very well.

In fact there is hardly any space between the end of the battery and the tip of the nose anyway, if you push the 18650 pack right forward. The battery can come back towards the servos, but I didn't want to do this as it would interfere with where I want to place my vario (home built from RC-thoughts).  

So i chopped up some lead bits. First I injected about 12g of hot 30minute epoxy and chucked the bits in while tapping the nose on the floor.  Most of the lead will go in over/around the battery in strips - there is reasonable room for this, so no problem.  

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isoaritfirst
On 27/03/2020 at 15:43, satinet said:

Making up pushhrods. The clevis is very slightly loose so I used some glass cloth to tighten the fit. Once this was dry the excess was just cut off.

The aluminium pushrods are quid flexible with this ids system. So i glued in some lenthgs of carbon tube to stiffen them up.

 

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When I have rods that need gluing into tubes, I usually wind a few carbon tows around the rod, then cyano and kicker them before sanding them back to fit tightly into the tube. The carbon make a great bond into the tube. If its a carbon tube I also then wind a few threads of carbon around the outside of the tube and sand back. (Cheap carbon tubes split easily)

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isoaritfirst

Hot Glue gun is good for fixing things in place, that may later need removing.

Also good for filling voids, around batteries etc. Holding aerials in place, Holding magnetic switches in suitable locations, sealing wiring.

Useful and quick.

Although quick is currently of no useful purpose. 😪

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satinet
1 hour ago, isoaritfirst said:

When I have rods that need gluing into tubes, I usually wind a few carbon tows around the rod, then cyano and kicker them before sanding them back to fit tightly into the tube. The carbon make a great bond into the tube. If its a carbon tube I also then wind a few threads of carbon around the outside of the tube and sand back. (Cheap carbon tubes split easily)

Good ideas Mike. Although bear in mind the carbon tube is only a stiffener in the aluminium tube and is a  tight fit.The wasn't supplied by servo rahmen. I just felt if you banged the flap the pushrod could actually bend. Although that isn't necessarily a bad thing....

The clevis is glued directly to the aluminium rod via the glass cloth. This required thickening per the photos. Although it would have been quicker to use super glued tows, i just didn't think of it. 

The green part is glue directly to the other end.

 

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satinet
1 hour ago, isoaritfirst said:

Hot Glue gun is good for fixing things in place, that may later need removing.

Also good for filling voids, around batteries etc. Holding aerials in place, Holding magnetic switches in suitable locations, sealing wiring.

Useful and quick.

Although quick is currently of no useful purpose. 😪

I do have a hot glue gun. You're right - all glues take on the properties of high tensile steel when in inaccessible places. I recently decided to change the battery on my stinger and deeply regretted the plan. I needed a heat gun to melt the glue it was stuck in with - only a couple of globs of goop.

I'll probably use the glue gun for the mag switch and vario. I might even glue the remaining nose weight in with it now you say. 

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isoaritfirst
2 hours ago, satinet said:

I do have a hot glue gun. You're right - all glues take on the properties of high tensile steel when in inaccessible places. I recently decided to change the battery on my stinger and deeply regretted the plan. I needed a heat gun to melt the glue it was stuck in with - only a couple of globs of goop.

I'll probably use the glue gun for the mag switch and vario. I might even glue the remaining nose weight in with it now you say. 

licked fingers as the glue cools are great at shaping and squeezing hot glue into place. Failing that a hot knife afterwards is good for smoothing.

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satinet

I installed a VARIO from built from an ardunio and MS5611 sensor.  Instructions at rc-thoughts.  

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satinet

Final fuse install minus placement of a wooden block to support the pushrod (epoxied to the white part of the outer)

Not shown - but there a mag switch in front of the RX. I prefer to have two power leads in to the RX, so things got a bit crowded. There is  mag switch, two output leads, the lead/connector for the vario, a charge plug and a balance lead (which as 3 wires). But I managed to get it in okay. I even broke out the ol' glue gun per Mike's instruction. I went with the 18650 size battery - this was a wise choice for space reasons.  With 3500mah capacity this is more than adequate.  

Final weight is around 2360g.  There was about 120g of nose weight to get CG to 102mm - in strips of lead flashing around the battery. On rc-network it seems the rear most position for the CG is 107mm so the model is balanced at that and has removable weights in front of the foam block to take it to 102.  I could have saved weight but using a lighter wiring loom for sure, but I didn't care about the weight for a slope model.

I don't have access to a torch or decent amount of lead so the wing ballast is not done. The model comes with about 600gr of weight for the fuselage.  I have got some hollow steel section which I intended to cast lead in to, but actually it would give more ballast than you need. But it's effectively free as I've already bought it and got the lead.  

Seeing as we are in midst of the end times I even broke out the good ball links for the Vtail (r.i.p Graupner). Obviously i tried to use as short arms as I could on the servo. This is easier with ball links than clevises.

As I have spare channels in the rx i might put a simple LED in as the one on the mag switch isn't visible. 

Flap travel is almost even - about a couple of mm difference which I can easily take out with the end point adjustment.  Definitely worth taking the time to jig it.  

I also installed a tray for the RX to sit on out of G10 board and balsa sheet.

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satinet

now to programme the travels and the maiden.............. 🤣

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  • 4 weeks later...
satinet

one final build task is was to add an LED to tell if the model is on or off. While the Jeti TX does warn you if you try to turn the TX off before the RX it only helps when the TX is actually on. The mag swith has its own LED but this is not visible in this case.

With LEDs you need the correct resistor to reduce the voltage to the LED. This is dependent on two factors - the colour of the LED and the voltage of the battery. In this case the max voltage would be 8.4v and the LED is an orange one. LED colour is voltage dependent. In this case 2.4 volts.  https://www.componentshop.co.uk/led-exp/  So the resistor I needed was 50x(8.4-2.4)=300ohm.  Which I happened to find.    I don't think it matters if you put the resistor on either side (pos or negative) of the LED, but I put it on the positive side (the long leg). 

As I had a spare port on the RX this was just added to the servo tray in a convenient location.

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satinet

Now just to programme the TX, do some wing ballast and wait for lock down to end. 

Lateral balance was close to spot on without any weight needed. 

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Kyri

Good thread, thanks very informative! Look great.

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satinet

The maiden flight has taken place this afternoon. Unfortunately  Burton Dassett was having a bad hair day and the (long) first flight was mostly scratching very hard trying to stay alive. Not ideal for a new model.  It's difficult to give assessment of a model in these conditions.  The throws I had were too soft in the roll axis. Not sure about the CG - feel light it would want to go back rather than forward. It seemed to turn well in EM style turns but the conditions didn't allow for much of that. 

The rudder on the model is noticeably effective and it flies very easily in the thermal turn.  Really it's very pleasant in the turn on the rudder with very little correction needed. Maybe I just got lucky on the thermal settings but it had very little tendency to over roll or under roll while turning.

 

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  • 2 weeks later...
Zim

Great build Tom. You're a bit of a Jedi now. Bravo.

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