Bates 1/5.5 Sea Fury Build

[Nick Somerville]

Could anyone who has been following who has retract/warbird  experience enlighten me on tracking angles please. From my understanding a little ‘tow in’ is helpful but is there an ideal angle for this. 
 

Preliminary tinkering with the retracts on the Fury have started with things pretty much lined up as per the plan. Wheels up has the axle on the C of G and when down the end of the axle is almost on the plan position. However to have the wheel sit near to flat in the well results in what appears to be too much of a ‘tow in’ angle when deployed so some compromise will need to be established. But how much?

[Danny Fenton]

I found this interesting,

 

however in my experience I now set the tracking dead ahead, and ball-race the wheels. 

 

Any rolling resistance and the you increase the risk of a nose over, but that's just my opinion.

 

Cheers

Danny

[Danny Fenton]

Just realised that the forum has softened that image tremendously, almost illegible ?

If anybody is interested in the original doc let me know and I will forward the original.

 

Cheers

Danny

[Piers Acland]

It's readable Danny.  Quite persuasive too.

 

Piers

[Nick Somerville]

Thanks Danny, That’s useful reading and certainly I want to avoid any nose over tendency. Fortunately the wing is deep enough to allow the wheel to sit at a bit of an angle so I will aim for wheels down and axles in line.

[Danny Fenton]

I think I had the wheels at an angle in the wheel bays on my Hurricane, but straight ahead when on the ground.

Just found a piccy and maybe not lol

 

 

For those adding retracts, here is a document that Tony Goodger of Unitracts sent me that is very useful.

 

 

 

This was how I sorted my Tony Nijhuis retracts, as well as the Hurricane as the pivot point wasn't per Brian's drawing.

 

Cheers

Danny

 

[Martin Harris - Moderator]

I'm yet to be convinced that toe angle in either direction is the answer to stability - there are too many different conditions involved.  While the toe out explanation above seems to make sense, what happens when the yaw (or other factors) induces lift from the outside wing and puts the weight on the inside wheel - the toe out induces even more yaw!

 

I'm with Danny on this and simply set my wheels parallel.

[Nick Somerville]

Very wet here today so a chance to spend time fettling bits of plywood for the retract mounts. The plan shows the rear bearer ending just after it passes through the angled rib. I decided to extend this to the next rib inside which I doubled up with some 1.5mm ply. For the forward support I chose to make a triangular bearer giving a large glue area against the main ply shear web. A small ply block bridges the two bearers together and this has a 3mm piano wire pin to lock the parts together. I will leave the gluing for another day as it is will be worth having a fresh look and final check before mixing epoxy.

 

 

 

 

 

 

 

 

[alan p]

Can understand the need beef the mounting up, but that ply looks past its sell by date.

Will it retain the screws well enough?

[Nick Somerville]

20 hours ago, alan p said:

Can understand the need beef the mounting up, but that ply looks past its sell by date.

Will it retain the screws well enough?

Decent quality birch ply Alan, but it was 20mm thick and I needed something around 15.75mm for the optimum seat for the retracts.  What you note as ply past its sell by date is the inner layers revealed after subjecting the pieces to my belt sander.  Mounted the retracts today after epoxying parts in place using generously threaded self tapping screws.  Tight pre drilled holes soaked in cyano to harden.

[alan p]

2 hours ago, Nick Somerville said:

Decent quality birch ply Alan, but it was 20mm thick and I needed something around 15.75mm for the optimum seat for the retracts.  What you note as ply past its sell by date is the inner layers revealed after subjecting the pieces to my belt sander.  Mounted the retracts today after epoxying parts in place using generously threaded self tapping screws.  Tight pre drilled holes soaked in cyano to harden.

Glad to hear it . If my inners were subjected to a belt sander they would look a bit of colour?

[Nick Somerville]

Another wet and windy day and a bag full of servo extension leads arrived, so a chance to crack on towards sheeting the wing underside.  The UP3 sequencing valve took me a while to set up correctly as I had purchased it 2nd hand and had no instructions. Those I found on the web helped but I still had a few hours of tinkering before everything worked as it should. It really is a clever little piece of engineering.

With all the plumbing and wires installed it has started to look rather busy towards the centre section. Certainly a bit of tidying required before sheeting. I slipped some heat shrink tubing over each of the servo connections so they can’t be pulled apart and check that they can easily be pulled through the rib holes in case of a servo failure. Servo hatch frames all in place and just the air and oil cooler entries to be sorted before sheeting can commence.

 

 

[alan p]

Hi Nick

What are the brass cylinders by the u/c? 

Definitley a crowded centre section

[Nick Somerville]

17 minutes ago, alan p said:

Hi Nick

What are the brass cylinders by the u/c? 

Definitley a crowded centre section

They are Ultra Precision 1" x 5/16" air rams that when mounted will operate the inner doors. Will require some careful geometry to set up as there is no variable throw like servos. 

[Nick Somerville]

Not pleasant again outside so a chance to start sheeting the underside. Satisfying work getting it buttoned up.

[Nick Somerville]

 

marking up the UC doors and leg covers before gluing down the sheets. Heavy duty tracing paper was used to copy the pattern from the plans and then a fine pin pricked through at key points after taping the tracing in place. Once these two sheets were adhered and given a fine sand to ensure a smooth surface, the area was sheeted over with a shiny plastic in preparation to take a mould.

the plastic was given a very thin film of veg oil and a lightweight rectangle of glass cloth laid on. The oil held it nicely in place without wetting it so I could use an indelible fine pen and ruler to again mark the outlines that were visible through the cloth. Next two layers of strand fibreglass wetted out on top and a final layer of my precious carbon cloth as it just didn’t look man enough. Left over resin was thickened with micro balloons and used as a paste to fix a pair of battens. Now I wait for it all to cure to see if it will serve as a suitably rigid mould. 

[Piers Acland]

Looking good Nick.  Fingers crossed.

Piers

[RottenRow]

Nick,

 

On one of his ‘Black Art’ instructional videos, Dave Platt does a similar process of laying glass cloth over the lower wing surface, he uses iron-on film as the release film.

 

In his case he actually makes the U/C doors directly from the laid up cloth (he doesn’t use it as a mould). It seemed to work very well.

 

Your Sea Fury looks superb! I’ve been following with both interest and admiration.

 

Brian.

[Nick Somerville]

Following morning. Didn’t go as well as I had hoped for. My lovely shiny, super smooth and pulled taut plastic film didn’t stay that way. I can only imagine the heat generated as the resin cured wrinkled it and as you can see in the photo I have lots of ridges to deal with. A tentative start with a Stanley blade used like a cabinet scraper looks like it may save the mould but will have to see.

Thanks for the comments, Brian and yes I was aware of the Platt technique. I just fancied a go at the mould for a smother surface but that didn’t happen. Still if the mould can be salvaged at least this way I can make spares if needed or loan it to any other Bates 1/5.5 Fury builders.

 

[Graham Davies 3]

Hi Nick,

I've been following your build and finding it totally inspiring. Aspirational even..

 

Would you mind explaining what the mould is for? I can usually work these things out, but not in this case? I would appreciate the thought process and what this achieves.

 

Thanks Nick

 

Graham

[Nick Somerville]

Hi Graham, as mentioned above a common way to make leg covers and gear doors is to temporarily iron film over the area and lay up fibreglass/carbon cloth with epoxy resin. Getting a super smooth outer finish requires a bit of elbow grease. Making a mould first means the outer surface of the parts should  be smoother and more accurate. On my previous model I used balsa and litho plate which was ok but a little flimsy.

[Graham Davies 3]

Thanks Nick, much appreciated.

[Nick Somerville]

Bit of a milestone this afternoon as have completed the final bits of the wing sheeting. I had a little detailing to do internally for the air inlets and radiator opening, which will be revealed later when cutting the apertures.  The mould is looking a bit better but still needs a some more finishing work before I can use it. I stuck an orbital sander on it and then some primer filler. Once cut back with fine wet and dry some hard wax type polish to fill the odd pin holes and provide a release for the epoxy laminates.

 

 

[Nick Somerville]

Mould given a couple of coats of a natural carnauba wax as a release agent and then laid up with: 1 layer of lightweight glass

cloth (28grm) followed by 2 layers of 210grm plain weave carbon cloth and then a layer if peel ply pressed on top soak any excess epoxy resin. Resin used was Easy Composites slow cure EL2 laminating resin. Look forward to revealing the result tomorrow.

[Nick Somerville]

Lifted nicely from the mould but the lay up was not really substantial enough, so replaced and added a further layer of the carbon cloth.