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Bates 1/5.5 Sea Fury Build


Nick Somerville
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34 minutes ago, alan p said:

Slightly off topic Navy Sea Fury T10 crashed yesterday (engine failure) Pilots survived but aircraft looks like a bin bag job in several pieces.

Yours is coming along nicely.

 

 

Yea i saw that too. My Sea Fury is in in the same paint as the one that crashed ? 

 

It looks pretty broken, but i think the wing and engine have detached at their mountings so hopefully its not a complete mess. Im sure they will repair it eventually assuming funds are available. They can team up with whoever owns the one that crashed a duxford last year and get a 2 for one deal on parts.  

 

As a tangent, i think its time CAA allowed someone to build new engines for these things. You can build most of these warbirds more or less from scratch these days but the engines are a different story. A modern remanufactured engine with modern materials has to be better from a safety point of view surely? The plans must exist for these old engines, so just make new ones. With modern machinery i really doubt it would be a big job. 

 

 

 

 

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I think there are a couple of companies around that remanufacture internal parts for the common engines on warbirds.

 

I don't know if anyone makes an entire 18 cyl double row radial from scratch.

 

Certainly there are smaller radials available. Verner? I think. 100hp sort of size though. Bit of an order of magnitude too small...

Edited by Nigel R
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The Centurus is a sleeve valve engine, 2100hp, beleave some have been converted to big Wright engines in the states.

 I had the priviledge of helping put a fury in its hanger some years ago no pushing on airframe moved rolling main wheels by hand trolley steered on tail wheel, big heavy aircraft needs that engine.  Sidney Cam masterpiece.

 

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Despite having viewed hundreds of Sea Fury ‘walk around’ photos and also having the benefit of a further stash of photos kindly passed on to me by a well known modeller I just couldn’t find any good views of the flaps insides. Fortunately

Phil at Fighter Aces had a few that he shared with me, though the ones of some flaps he had made for one of his Bates 1/4 scale Sea Fury builds left me feeling wanting. The fine detailing was quite superb and so I thought I better make some effort to go some way to improve what I had started.

 

I made a few hard 1/16 balsa horns and glued them to some scrap sheet hinged with tape to test the geometry and then fretted the optimum shape from 1.5mm G10 fibreglass sheet. 

 

Some of my riblets were in the wrong place and there was a few other infill details that needed adding along with quite a few rivets. Didn’t take as long as I expected and after epoxying the G10 horns With some carbon tow reinforcement a light spray of primer over sanding sealer revealed a satisfying result.  
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Spent an evening sorting servo positions for the 4 flaps which will be driven by individual KST X10 servos. To my dismay I immediately noted a small amount of play at the flap horn and realised I had drilled them all with a 2mm bit instead of the usual 1.5mm, Doh!!.  I had a scroll through 8 pages of clevices on the Nexus website and none with 2mm pins were listed, so have ordered two pairs of aluminium clevices with 3mm removeable pins held in with circlips.

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I also ordered a pack of heavy duty flat hinges for the flaps and as these have removeable pins I guess I may have stumbled on a setup whereby each of tje flaps could be removeable. Silver linings.

 

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Danny Fenton has been a champion of the RDS system for slop free hidden actuation of flaps and ailerons. It’s weird how some things are difficult to get ones head around and the bent drive rod in a slot has been a mystery to me that rubs against conventional methods. Nevertheless if it work for others and it has numerous benefits then why not. As previously mentioned I have opted for centre hingeing the ailerons and RDS is suitable for any hingeing except where the hinge line is above or below the surface. I had seen a Robotics parts distributor listing an output shaft to suit various servos. It appeared that one of the 5 supplied output adapters would suit my KST servos so to check I gave the company a call ( https://www.active-robots.com ) Turned out they were in a small industrial estate 10 minutes from home and next to a large school where I work part time as a running coach. Needless to say I popped over to pick up the parts ‘tout suite’.

Armed with the output shafts and some lengths of 3mm steel rod I quickly made up a simple mock up of the RDS system to convince myself that it was worthy of integrating into my Fury.

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Well boy it works well and I am now a total convert. A 25-30 degree bend seems optimal for the deflection needed on a WW2 type warbird to ensure maximum use of servo travel. Can't wait now to construct my ailerons and set it all up for real.

 

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1 hour ago, John Stainforth said:

Those aluminium clevises are great, but I found the circlips really hard to fit and very easy to flick across the room! I'd be interested to hear if you find a sure-fire way, or special tool, for fitting them.

Ha ha! Yes John, I wondered at the wisdom of ordering them as I also have a history of fun and games with circlips. I shall probably fit them to the horns with the flaps in a white box ?

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Been sorting through a box of old balsa I purchased, for the aileron leading edges, from BMFA Classified a few weeks back and quite a few sheets have the old names like Solarbo stamped on them. This one has an Artml sticker along with an environmentally friendly badge. Australian Balsa, very appropriate for a model that will be detailed in am Australian Navy scheme!

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Fabulous to see others realise the benefits of the RDS system Nick, and you have managed to source adaptors which is impressive. As you know I make my own adaptors but these look much easier for everybody to access, can you show links to the bits and bobs?

 

You know you can remove the Robart hinge pin and replace with a length of piano wire through all the hinges. also this helps to perfect the alignment.

 

Well done ?

Cheers

Danny

Edited by Danny Fenton
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Sea Fury!

My favourite piston powered aircraft of all time but I can not see me ever building one due to the sheer amount of work involved as shown in this thread.

 

All power to your scale builders elbows

Edited by FlyinBrian
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4 hours ago, FlyinBrian said:

 

Sea Fury!

My favourite piston powered aircraft of all time but I can not see me ever building one due to the sheer amount of work involved as shown in this thread.

 

 

Tbh I find it comforting to have so much to work on for a model like this. The satisfaction of the journey is equal, if not more, to the destination. Also the financial investment is significant so it wouldn’t work for me to be building more than one of these on a regular basis.

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A wet day here yesterday so some progress on the ailerons. The RDS pockets  were made up with some pcb board with the copper sanded away on the inside as I recall metal to metal rubbing is not ideal.

 

I was able to retain the laser cut ribs but needed to build up and shape a different section for the leading edge for the centre hingeing. In these pictures You can see the pocket blocked in with scrap balsa to set it firmly on the centre line and the scrap  balsa pre slotted for the hinges. Carbon tow wetted with pva has been laid on the inside of the trailing edge to maintain strength once it has all been sanded back to a scale thickness. Just some thin strips  .4 mm ply to add in around the line of the trip tabs and the upper sheet can be added prior to final sanding. It’s not been exacting work having deviated from the plans, but I have been able to build in a small amount of washout that at least looks right.

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image.thumb.jpeg.542e66354d4af97eb892798324a7eae8.jpeg
 

The ailerons have been set aside for a final sanding once the lower sheeting and shroud is in place. The key task for inside of the wing is to sort the retract mounts. Naturally I am procrastinating over this and instead have made a start on the pneumatic and flap control systems. The UP3 valve is for the retracts and gear door pneumatic actuators and will be operated with an old glider wing servo I had. This clever piece of engineering has a needle valve for each operation so that doors and wheels can be sequenced and slowed to give more scale like actuation. My tailwheel is mechanically operated so I may be able to put its servo on a Y-lead with this one and use the ‘Servo Slow function on the transmitter so it also has a scale operating speed.

 

The JR Matchbox is for the four flap servos as previously mentioned in this thread. The 900ma LIfe Battery is to tun the flaps only. Not cheap but I am not keen on having to remove batteries for charging as recommended for Lipos. I need to frame the area out for a hatch and add a switch, but it rather looks like I am going to have to get on with mounting those retracts next ?

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4 hours ago, Nigel R said:

What does the multi box do? reverse & end point adjusts for each of the four servos?

 

UP3 looks neat - what door actuators are you using?

 

Nice work by the way. ?

That’s correct,Nigel the Multi Box (AKA JR Marchbox) does exactly that.  It can be powered by the main battery or as in my case by a separate battery. I haven’t decided what battery set up I will use for the rest of the servos and receiver yet. 
 

Ultra Precision 1" x 5/16" air rams are what I have for the gear doors. 

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Mounting the two aileron servos had been bothering me a little as it seemed a bit of a chicken and egg task. On the one hand The servos need mounting and hatch frames fitting prior to sheeting the lower wing but just a small change in angle of the servo seating translates to a larger vertical movement where the torque rod exits the trailing edge of the aileron cut out; just where it needs to accurately mate with the fine fitting box in the aileron.  It’s usually challenging enough to construct tight fitting shrouded ailerons without any binding, but the RDS system requires a further step in precision.

 

I decided that an adjustable mount was required and fortunately the KST X10 servos are made in such a way that a solution presented itself.  Firstly a 1.5 local ply shear web was added against the outside of rib no.9. Next two soft/light hardwood bearers (Aspen) were added and the three servo holes marked. The small rear bearer was drilled 2.5mm and a 3mm allen bolt was used to create a thread that was hardened with cyano. A nut was spun up to near the top of the bolt and locked with superglue and after dropping this through the lug a nylock nut spun up to lightly kiss the underside. With the two front screws lightly in place the rear bolt can be turned until the servo is about level and from there can be adjusted incrementally up or down to give the optimum exit angle of the torque rod before tightening the front screws.

 

When the wing is complete, glassed and primed and the ailerons glued in place the final adjustment will be made and a small hardwood bearing can be glued to the inside of the trailing edge exit hole to give added support to the torque rod.

 

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Genius!  I have struggled in the past getting RDS torque rods properly aligned - I resorted to measuring angles off the plans combined with some pretty rudimentary trigonometry.  But this is far more elegant.  One question Nick.  You say that the final adjustment will be made after glassing and priming.  Do you envisage a small pilot hole in the wing sheeting for making this adjustment and then plugging the hole with filler?    

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46 minutes ago, Piers Acland said:

Genius!  I have struggled in the past getting RDS torque rods properly aligned - I resorted to measuring angles off the plans combined with some pretty rudimentary trigonometry.  But this is far more elegant.  One question Nick.  You say that the final adjustment will be made after glassing and priming.  Do you envisage a small pilot hole in the wing sheeting for making this adjustment and then plugging the hole with filler?    


Piers, there will be the usual servo access hatch as servos have been known to break/fail, hence no problem envisaged making any adjustments. In any case as mentioned I will need to get in to glue the small 3mm drilled hardwood bearing. That task will be fiddly but if the bearing is already slipped onto the rod it will just need a dab of glue and pressing home when all is ready.

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Hi Nick, I appreciate what you have done, but if you don't mind can I suggest how I align the servos to the arm?

First I mount the aileron temporarily, but accurately.

Slide the rotary arm into the pocket. Slide a ply or hardwood block (or any bearing material) with a hole the size of the torque rod over the rod and glue against the rear spar (where the torque rod passes through). Turn the rod (deflect the surface) to centralise the bend on the hinge-line. Mark the rod against the bearing block with a permanent marker so you know its depth.

Mount the servo on the ply plate, that is sized to fit between the ribs perfectly.

Slide the servo and plate onto the rod. The plate and hence the servo will be aligned perfectly. Glue the ply plate to the ribs. Remove the servo and add 1/4 stock to reinforce the servo plate to the ribs. Remove aileron and rod, refit servo.

I think trying to start with the servo is what is causing you grief, start at the aileron and pocket.

 

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The inventiveness is brilliant to see though, well done ?

Cheers

Danny

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