The Seagull has landed

[onetenor]

Nylon , Terylene / crimpalene various braids from fishing tackle shops.All "unbreakable" and the braids no stretch and various thicknesses and breaking strains. You 'll cut your fingers before you snap any of these.Re  the KEVLAR and DYNEEMA you don't you don't need to get your hands on it . Just buy it believe me. And keep your scissors sharp.Also good for closed loop controls                                                                                                                                                                                                                                        Edited By onetenor on 13/06/2018 22:53:47

Edited By onetenor on 13/06/2018 22:59:37

[cymaz]

Posted by john stones 1 on 13/06/2018 22:36:28:

I use these, shrink wrapped if its buried somewhere and doesn't need unclipping at knock off.

I use them...never,ever had one fail. There, that’s ruined it !

[Gary Manuel]

Posted by john stones 1 on 13/06/2018 22:36:28:

I use these, shrink wrapped if its buried somewhere and doesn't need unclipping at knock off.

I use them for aileron leads that need to be connected during assembly. I prefer thread for permanent connections.

[Gary Manuel]

Posted by onetenor on 13/06/2018 22:39:02:

Nylon , Terylene / crimpalene various braids from fishing tackle shops.All "unbreakable" and the braids no stretch and various thicknesses and breaking strains. You 'll cut your fingers before you snap any of these.

Sounds like similar stuff.

[john stones 1 - Moderator]

Posted by Gary Manuel on 13/06/2018 22:47:42:

Posted by john stones 1 on 13/06/2018 22:36:28:

I use these, shrink wrapped if its buried somewhere and doesn't need unclipping at knock off.

I use them for aileron leads that need to be connected during assembly. I prefer thread for permanent connections.

Ah cheapskate is it, giz a nudge I've a spool in my box you can have.

[Ron Gray]

An alternative thread to use - dental floss! Light, strong and cheap.

Edited By Ron Gray on 14/06/2018 06:42:14

[Rich too]

I use heat shrink - it ain't coming apart! Very tough.

[Rich too]

Posted by Gary Manuel on 13/06/2018 18:57:42:

The epoxy within the aileron control horn is now set, so I'll fit the wing servos and controls next.

First job is to make up a short servo extension lead.

Secure the plug / socket with "unbreakable" thread.....

..... and heatshrink.

Then protect the wiring with 3mm spiral-wrap. Then thread the wire down the wing using my trusty length of waxed string with a large nut weight on the end.

Servo holes marked, drilled and hardened / strengthened with cyano.

Servo and controls fitted. Supplied clevis keepers (fuel tube?) and 3mm lock nut fitted but not applied at this stage, as I expect that I'll be making adjustments later. The short HiTec servo arms provide well in excess of the recommended aileron throws, with the clevis on the second longest hole. There is plenty of aileron movement to allow this to be increased later, or decreased as required. The servo and control s have been centred and tested for full movement using a Turnigy servo tester.

Note the 3mm screws are positioned on the central narrow part of the rod, where they are free to slide as described in the rudder problem in my previous post. They will be lid onto the threaded part and tightened up to the clevis after I have finished my adjustments.

I'm not a fan of plastic horns on big models. In fact, I threw away the fibre ones that came with my 100cc Sbach! Is your control horn on the servo longer than the surface control? It looks a little short?

Nice build

[Gary Manuel]

Posted by Rich too on 14/06/2018 06:47:45:

I'm not a fan of plastic horns on big models. In fact, I threw away the fibre ones that came with my 100cc Sbach! Is your control horn on the servo longer than the surface control? It looks a little short?

Nice build

I'm not a fan of plastic horns on large models either. This is only a 64 inch span and plastic horns are well up to the job.

There is easily enough travel using these horns. I'm getting a good 2 inches of travel as it is compared to the recommended throws. I have the option of moving the clevis out by a hole or even putting the next size standard plastic horn on if I feel that it needs more. The hinges will take more without straining them.

[Rich too]

Ignore me, I was referring to mechanical advantage and of course talking complete rubbish I got it round the wrong way!

[Bruce Collinson]

Gary,

I'm building one of these for a DLE 20. It's fairly well on, stalled by flying weather and the tank. Whilst I remember, I've fished with Dyneema/Spiderbraid/gelspun etc and they share characteristics; hard to cut, hard to knot and will cut your digits clean off before they break. Allegedly. Try a simple overhand knot in the free end, it will stop knots slipping. Reference angling knots online for anything fancy. Dot of cyano?

I have a spool of kevlar flytying thread, similar but much finer, great for wrapping onto c/f tube before screwing clevises etc. to prevent splitting.

I may well use Graupner 4mm alloy horns for the tail struts as I have some left over from a Maxford Mentor and they're neater and lighter.

Anyway, the tank; the least impressive bit of the whole plane so far; what are you doing to secure it, bearing in mind it's awkwardly accessible and rather hard mounted?

Have you decided on the C of G, upon which there is much online speculation and a large degree of uncertainty?

I suspect yours will maiden first and I will be keen to hear how you get on. BTW where does the 3mm wrap come from? Not seen it but it looks sensible.

BTC

[Gary Manuel]

Hi Bruce.

I'm with you with the dot of Cyano after tying the knot.

I havn't decided on the tank yet, but I do have a couple on standby and I'll decide which one to use when I come to fitting it. I usually pack tanks with some sort of foam or polystyrene. I'll post what I do here.

For the CoG, I'll start with the middle of the recommended range and work from there. I'll be aiming to get it as far back as I can without making it unstable of hard to land - hopefully without adding lead. The canopy is massive, so there's plenty of scope for moving the batteries around (I'll be using 2 x LiFePO4 batteries).

The "spiral wrap" is easy to find on eBay. I use the Natural colour, 3mm for single servo leads and 6mm for tidying up several cables together.

Edited By Gary Manuel on 14/06/2018 15:17:26

[cymaz]

To get the most resolution on the servo...it’s clevis as close to the servo centre as possible and on the longest distance on the surface horn. Also seal all the gaps on the hinge lines.....super build

[Bruce Collinson]

Gary,

Thanks.

There's a strong implication that Seagull's recommended c of g is at best ambiguous and at worst erroneous; caveat volucres!

Never even considered binning their tank, that may well be the solution, dispense with the awkward former/elastic band and wedge from the back. Ta. Thanks for the wrap lead too.

BTC

[Gary Manuel]

I'll look into the CoG business. Thanks for the warning.

[Gary Manuel]

I've had a read up on various threads, where people have had problems with the CoG. I haven't found a definitive explanation, but I'm pretty sure that the people who have had the problem haven't read the instructions manual properly. This clearly states that the CoG should be 7cm to 8cm from the leading edge MEASURED AT THE WING TIPS. I reckon that people have been confused by this rather unusual way of specifying the CoG and have been measuring from the wing root as they would for most other models.

I've just done a few quick measurements on my model as follows:

• Both wings marked at 7cm from the leading edge at the TIPS.
• Piece of string stretched between the two marks with the wings fitted to the fuselage.
• Wing roots marked where the tight string crosses the fuselage.
• Distance from leading edge at the wing ROOT measured to the mark I just made. It is 15cm.
• Distance from leading edge at the wing root measured to the centre of the wing tube for reference. It is 12.5cm.
• Root chord measured. It is 44.5cm.

The lower recommended CoG measurement of 7cm from the leading edge, as measured at the wing TIP can therefore be quoted as 15cm from the leading edge, as measured at the wing ROOT.

Similarly, the upper recommended CoG of 8cm from the leading edge, as measured at the wing TIP can be quoted as 16cm from the leading edge, as measured at the wing ROOT.

This 15-16cm range is consistent with what others with well set up models are reporting.

Now, if I didn't have a manual or the wonderful internet to help me, I would have guestimated a SAFE CoG at about 1/3 of the root chord = 44.5 / 3 = 13.35cm from the leading edge, measured at the wing root. This is not a million miles away from the manual recommendation.

I'll be aiming for a CoG of between 15cm and 16cm from the leading edge, measured at the root. This is 2.5cm to 3.5cm behind the centre of the wing tube. I'll clarify where the CoG actually is for the maiden and I'll report back on how it flies.

[Bruce Collinson]

Thanks Gary. This is consistent with what we (my former tutor) and I concluded. How far off flight is yours? I’m about to start tank measuring ....

[Keith Berriman]

Hi Gary "Well spotted" I had an Seagull Edge 540 Electric and only by reading the instructions three times did I find the same wording for CofG set up being measured from wing tip.  I followed your set up to be able to mark the wing at root tip next to fusalage 

Edited By RC Plane Flyer on 14/06/2018 20:05:19

[Gary Manuel]

Posted by Bruce Collinson on 14/06/2018 20:00:14:

Thanks Gary. This is consistent with what we (my former tutor) and I concluded. How far off flight is yours? I’m about to start tank measuring ...

I've not even started on the fuselage yet, apart from shortening the engine box. I'll be a while yet.

[Gary Manuel]

Next job is to fit the fuel tank.

This is the tank that came with the kit.

It is perfectly usable, but as I'm fitting an over-sized engine, I think I ought to fit an oversized tank.

I'm not convinced about bending the plastic pipes and then using a heat source to set the required angle. I've used 2 straight ones for the dual clunks but I've replaced the vent tube with a copper one.

Completed tank with the pipes identified.

The kit comes with two special formers for holding the tank in place.

The rear one will be of little use with my tank, but I'll probably use the front one, which holds the tank clear of the firewall. I could make a similar rear one to fit my tank but I'm not keen on it anyway. I'll have a think about this.

[Gary Manuel]

Before I can permanently fit the fuel tank,I need to fit out the throttle cable route, which will pass down one side of the tank.

The throttle servo can either go HERE, if the throttle cable is best routed UNDER the wing tube.

The kit comes with the parts to make a servo tray, in the event that the throttle cable needs to be routed OVER the wing tube.

I'll be needing the servo tray.

The kit comes with this type of snake. I'm not a great fan of Z bends and the type of servo arm fittings that grip the inner snake by tightening a screw onto it.

I'll be using a plastic snake instead. Here it is routed over the wing tube, down the side of the tank and out of the firewall at the position I marked earlier..

Here's the servo fitted with a nice short metal arm and ball link connector. I haven't glued the red snake outer in place yet. I'll wait till I sort the engine end of the servo cable later. Servo is a bit over-rated for the job, but it's one I had spare from a casualty (as are all the servos on this model).

[Bruce Collinson]

rSomeone tell me how to incorporate photos into this thread.

Gary, this is very helpful. I too struggle with the rear tank former and will fit a larger tank hopefully to the front former but then stuffed with foam rubber. My throttle servo is just behind the firewall with a short thick Bowden cable and the ignition module is on the in side of the firewall, both on the premise that tail end weight to achieve c of g will be exponentially lighter overall. It means I have several cables to route around the tank but I supposed they will be simpler and cleaner than routing a throttle linkage. Please keep the photos coming. BTC

[Gary Manuel]

Posted by Bruce Collinson on 15/06/2018 21:42:24:

Someone tell me how to incorporate photos into this thread.

You need to create a photo album and add photos to it first.

https://www.modelflying.co.uk/forums/postings.asp?th=66178

Then you can add the add any photo within any album to your thread by clicking on the camera icon.

Edited By Gary Manuel on 15/06/2018 22:13:10

[Gary Manuel]

There is a pre-cut slot in the top-rear of the engine box and a smaller one in the bottom-rear .....

..... to allow the special front former mentioned earlier, to be slid and glued into.

I have used pieces of lightweight packing foam to protect the front of the tank and on underneath the tank to raise it to the level where the neck is aligned with the hole in the special former.

Then used offcuts of foam to pack the tank in situ.

Then a piece over the rear with a strip of balsa to hold everything nice an tight.

I'll either tack this balsa with Cyano of think of some other way of fixing it later, but it feels like it's not going to move far anyway.

I think I'll also cut a vertical slot in the rear piece of foam, so that I can see how much fuel is in the tank with just the canopy off.

This is how the front of the tank looks with the neck protruding through the hole in the former .....

...... and how the firewall looks.

[Gary Manuel]

That's better