Canadair Sabre F.4 - XB673

[jackmav88]

ER/Dennis,

What grit sandpaper should I use to sand down the original paint?

[ERJets]

Aug 30, 2008 0:01:35 GMT 8 jackmav88 said:

ER/Dennis,

What grit sandpaper should I use to sand down the original paint?

For me I am using either 240 or 320, after paint being sand down I use 800 to smoothen the surface a little before glassing.
Please ensure that the surface is dust and wax free before proceed with glassing.

[dennisp]

So to continue the build.....

Wing wheel wells

As I mentioned earlier the wheel well skin is very thin and is the weakest part of the entire wing, so a little attention is required here especially as we have those heavy duty retracts.

To continue the classic “D” box one more step the wheel will be sheeted with light balsa for the floor 1/32” and the sides 1/16”





Wing is now much stronger with very little additional weight from the balsa and wood glue.

The plumbing

This is going to be tricky as we have a lot of pipes to move around the wings and also exit to the fuselage, first step is to make and access box in each wing for the air pipe “T” connectors and there exit to the fuselage. To reduce the size of the slots to the fuselage my idea is to have the up / down pipes in one groove and the aileron servo wires and the tank in the other slot, thereby keeping the slots as small possible. As suggested by Ernest I shall use foam to fill the slots but not the access areas as I may need to go there later for those awful air leaks….



Here is the pipe exit hole for the feed to the drop tanks.



The big moment has finally come to fit all the pipes, aileron servos and extension leads, actually it was a non event having made the holes ready for the pipes and wires in the wing….





Do remember the pipe routing is different for each wing due to the air nipple location on the retract..

Next step will be some minor work to fit the aileron horn mountings and then we are getting very close to shutting the up the wing with the Depron covers…

As always stay tuned for the next part……

[dt8666]

Well... very cool and nice. how you are going to add the carbon tube to prevent it to clap "hand"

[dennisp]

Thanks DT my current thought is that from the retracts in the wing is super solid, but as you say need to protect for the clap hand feature.

My current plan (changes daily) is to use 2 ounce cloth on the entire wing and a double layer on the root area to the retract mount, much the same as those old IC models with foam wings where you had the center bandage. This should be enough as the break would occur at the bottom and not the top.

If one looks at pressure ratios of a wing the major lifting forces are at the inner parts of the wing so I should be lucky. There is no doubt that the Depron filler plates add a lot of strength to the wing so I shall pay special care to ensure they are glued evenly and well.

[dennisp]

No problems LAH.... , I hope you are settling in sir, have you been to Fly Eagle yet....? well I have to ensure that your priorities are correct while you are in China.

DT not clappy clappy he is king of Hover Bother....

[dennisp]

Thanks Ernest me stll fancy a Tiger meet Rafale EDF if you do not mind can you check the factory price for me. Any problems then do not worry sir, hope that negotiations go well for you.

[dennisp]

Thanks sir, take care and enjoy China..

[dennisp]

With visitors this weekend my spare time was a little limited, but some good progress was made even though not as much as I hoped to achieve.

Ailerons

As always I did a dry fit of where the FF aileron horn would go and something was just not correct, the best solution for any push rod is to be at right angles to the hinge, in the case of the model it was a long way out. So as always yet another modification fitting a wood block for the control horn to get the push rod at the correct angle. In the picture below you can see the correct alignment by the solid line and were the push rod would be using the FF alignment by the arrow.



I checked with DT on how he had hinged the ailerons on his F-86 and his advise was to use Du Bro hinge tape, great I just happen to have some of that. The other option is to go for hinges but due to the angles the wing an aileron are made this would have necessitated a small balsa plate on the aileron hinge surface to get the aileron back to the correct length. This is a bit difficult to describe but if you have the kit just look at the wing and the aileron and it will obvious what I am spluttering on about, and I have done enough modifications for the moment.

Drop Tanks

Just need to do a small modification to get the air pipe into the drop tanks, namely just a hole in the foam of the drop tank and make sure the air pipe has a nice easy bend into the wing.



The next picture shows a FF air tank in the drop tank, it actually looks lost in this giant drop tank but diameter wise with the top on there is just a little clearance so there will be room for the air pipe.



Wing covers

One final check before the wing covers are fitted, servo’s function OK and centre ?, seal the ends of the air pipes in the wings up with tape as by Murphy’s Law that glue will find a way in for sure. I used slow EPOXY (30 minute) for the fitting of the covers, it is essential that there is glue on all the foam surfaces that will butt against the DEPRON this being the main strength of the wing. If you decide to use wood glue or PVA make sure that all oil that is on the surface of the DEPRON is removed otherwise you are gluing foam to oil....





A quick rub down so that the DEPRON panels are flush with the foam wing core and then time to put the first piece of cloth on the bottom.

Covering the wing

No real rocket science here just a lot foam to work with, like using covering material always cover the bottom first and take time to get the edges to roll over, it can be done just takes a little time.

Now I know why we have a balcony ….. it is for drying PVA pasted wings….!!



Stay tuned for the next part of the build …..

[ERJets]

I like the idea of having the air bottle being installed in the drop tank. Cool.
Please ensure that there is no air leak before you starts to epoxy and install all equipment in place. May I suggest to you to secure air tubing connection on the the air bottle's nipple with safety wire.

Something like this..