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#4526268 - 06/19/20 09:42 AM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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This is the prototypical genius of the British Man in the Shed.

Utterly amazing.

Inline advert (2nd and 3rd post)

#4526305 - 06/19/20 01:47 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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How long is Dart's plane?

Just wondering compared to The length including turrets will come out at circa 5.02m! ??

reading

edit: Oh, and you are gonna need a bigger boat shop!

Last edited by Nixer; 06/19/20 01:57 PM. Reason: Bigger

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#4526986 - 06/23/20 04:09 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: RSColonel_131st]  
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Originally Posted by RSColonel_131st
This is the prototypical genius of the British Man in the Shed.

Utterly amazing.


Thanks. I can't tell you how amazing it is to get such feedback after years in the "shed" bashing away solving problems or making things!

I've now completed the lengthening of the datum and measurement bars on the jig. I still need to mark the datum bar with all the frame positions (all 196 or so of them!) (two lots of 98 staggered) which define where geodetic members on the fuselage meet with the longerons.

The next phase is sourcing the pneumatic rivet-gun for the miniature rivet-gun, and checking that I can get this tool into the geodetic channel as planned during assembly. Once proved, I can then finalise the dimensions and design of the channel, and get a small prototype run of extrusions.



Last edited by Fidd; 06/23/20 04:11 PM.
#4526990 - 06/23/20 04:23 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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I'm utterly amazed at this but as a Brit I fully understand that we have people like Fidd beavering away in their sheds smile

I notice that the model is to be flyable which both delights and horrifies me in equal measures. Will you have any safety mechanisms built in to prevent the unthinkable?


EV's are the Devils matchbox.
#4526998 - 06/23/20 05:10 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Chucky]  
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As it'll be over 20kg in weight, it comes into a weight category requiring multiple redundancies on the transmitter, receivers, servos, batteries and actuators, to get its permit to fly. So yes, it'll have numerous additional safety measures to prevent a total loss of the airframe. A hard-landing remains a possibility of course, or an engine failure on take-off likewise. The way I look at it, is that if I get 50 flights out of it before it's damaged or written-off, then there's 50 opportunities for getting some footage from within the turrets and airframe. If it does have a hard-landing and suffers damage to the airframe, then relative to other construction techniques the geodetics are reasonably straight-forward to repair, as I should be able to produce replacement geodetic members without difficulty.

The size of the model will be pretty big. At 1:3.7 scale the wingspan comes out at circa 7.1m or 23 feet. The intention is to have the wings separate for transport just outboard of the nacelles, as per the real aircraft. In order for the prop' arc to clear the workshop doors, the airframe will sit in a custom trailer, tilted about 45 degrees about the longitudinal axis, the outboard wings being fitted at the airfield, where the turrets and supporting structure will likewise be fitted. From a design point of view, the larger the model is, the easier it is to make, and the more tolerance for weight there is if it is to appear to fly at the correct speed over the ground. A larger, heavier, aircraft model also has better speed stability and more inertia. So there are lots of reasons to build it large, especially if one is seeking to produce it using the same construction techniques.

Last edited by Fidd; 06/23/20 05:23 PM.
#4527119 - 06/24/20 10:39 AM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Crickey...Darts 7/8ths Bebe replica's wingspan is only 10cm longer!
What an amazing and skillful engineering enterprise.



#4527246 - 06/24/20 05:45 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Hi, mine hasn't been built yet, so it remains to be seen if it turns into skilful engineering or so much scrap aluminium! The coming year should see some simple test shapes made, at which point that particular question may be a little clearer.

#4527281 - 06/25/20 12:59 AM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Looking fairly skillful so far... winkngrin

and that's the biggest understatement I've made in a longgggg time.


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#4528438 - 07/02/20 07:18 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Cheers. Not much happening at the moment, I've the "lockdown blues" and can't seem to summon the enthusiasm to get cracking just now. Too much time on my hands! Part of this related to the plethora of dependencies in the next stage. But I hope to do so in due course. I need to replace the PC I usually employ for CAD work and lay hands on the miniature rivet-gun before finalising the cross-section of the extruded alloy channel. After that, I need to fabricate some test flat pieces, followed by building the devices and inserts required to curve the channel to a specific curvature, and "notching" each member through 50% of the thickness where they cross with the other. Since writing last, I've figured the notching out. For a long time I was intending to grind these out with an angle grinder, but couldn't get past the problem of this tending to leave a readily crackable surface along the horizontal portion of the notch.

I've now decided to make that a 2 part operation. it'll involve making a carriage for my angle grinder able to move 25 degrees of so either side of the CL of the notch. With a cutting disc, rather than a grinding disc, I can then make two slits through 50% of the channel which taper towards each other, and then I'll simply use a chisel type tool, with curves at either end, to either punch, or be pressed through the metal via something like an adapted bearing press, to make the final cut. This should result in an accurate notch, without the scope for seeding cracks due to use of a grinding wheel.

But first, I need to get a new pc up and running.

#4528458 - 07/02/20 09:33 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Man, you are doing some fabulous work. Way beyond my skill or patience.


Good people sleep peaceably in their beds at night only because rough men stand ready to do violence on their behalf.

Someday your life will flash in front of your eyes. Make sure it is worth watching.
#4528617 - 07/04/20 01:16 AM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Thanks, but I'm sure it's not beyond your skill. When I first started this project, 5 years ago, all my drawings were done with pencil rules and protractors at an old fashioned drawing-board! Since then I've taught myself CAD in Fusion 360, a great free program for (hobby use) which has a very helpful online community. Learning to output designs into .stl files for printing followed, and then discovering that SLS nylon (3d printed) could be readily drilled/hand-tapped and screwed together. (female threads of M3 and above can be printed and then cleaned out with a suitable tap).

After that, as far as the turrets go, it was just a great deal of revisions to get the mechanisms working. The hardest parts were probably getting the rams to lift the gun-cradle properly - my first attempt using home-made electric linear servos didn't work well - so I moved onto pneumatics which worked really nicely. The next problem area was the compound-curved window panels at the front of the turret cupola. I knew from when I was plotting moving parts positions when working on the rams, that there was very little room at all between some moving parts and these window panels, and it took a long time to research how to make them this accurately. I then learned how to make a silicone mould, how to cast it with epoxy resin, to heat-treat same and then fill/polish the resin tool prior to vacuum forming it with thin polycarbonate. Nearly everything in the preceding two paragraphs is stuff I've never done before, all of it was learned during the course of the project.

Which means nearly anyone can do it, it's merely a matter of hammering away at new problems until you work out how best to build what you need.....

#4528620 - 07/04/20 02:11 AM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Some of us are good at some things...

I have never seen seen OG's gunsmith skills in person, but knowing his attention to detail, I am pretty sure they are at, or above the skill level of many manufacturers.

You sir are a prototype level engineer. Yeah, I know, a little late for the prototype.


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#4528698 - 07/04/20 05:35 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Nixer]  
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Well it's true I don't mind complicated projects. Here is a wire-frame picture of the turret without cupola, one of the traversing ring, and one of the axle area of the gun-cradle. I did not usually work in wireframe for obvious reasons! in the end the traversing ring was slightly simplified by removing 1 of the 3 sets of bearings, and in the light of difficulties wiring the turrets, the master-drawing of it now has much larger internal apertures for concealed wiring.


Attached Files 554fn5wire.jpgGulp.jpgMK V fixed ring assy wire.jpg
Last edited by Fidd; 07/07/20 08:25 PM.
#4533345 - 08/12/20 05:18 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Stunning work. I wouldn't even know where to start.


cheers
Gareth

UNDERSTEER - is when you hit the wall with the front wing.
OVERSTEER - is when you hit the wall with the back wing.
HORSEPOWER - is how fast you hit the wall.
TORQUE - is how far you can take the wall with you.

Read my scale modelling blog at www.latibuliser.com or mfhmazda787.com
#4533859 - 08/17/20 10:11 AM Re: FN5 turrets for RC Wellington 1:4.5 [Re: goon]  
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Originally Posted by goon
Stunning work. I wouldn't even know where to start.


You'll laugh, but attached is the product of the first evening's work on the "turret" using CAD. After drawing what my wife called "a lovely flower-pot dear" it was merely a matter of continuous revision from looking at photographs. Learning CAD with Autofusion 360 is reasonably easy, although compound curves are a bit tricky.

I've just finished expanding the jig for the fuselage build and am now getting all my beans in a row for the initial metalwork on test-pieces. It'll be some considerable period of time though before I have much to shew for it.

Attached Files timsplantpot.jpg
#4542894 - 10/31/20 09:18 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Hi all,

It's been quite awhile since I last posted. I've finished re-working the rotatable "jig" and lengthening it for the new scale of 1:3.7 (same as the turrets) and correcting some known errors on the master-drawings in case I ever wish to make better turrets. At the same time I'm revising the design of parts of the model which gave great difficulty. Now that's the workshop has turned bitterly cold, I'm hammering the CAD designs for the fittings required to join geodetic channel together, and also the alternating alloy and rubber fittings, which will be threaded onto steel-cable and then used to keep the cross-section of the extruded alloy geodetic channel from collapsing when it's being curved. So there's quite a lot to do. I have also established that the Avdel Micro-rivets riveting tool, will fit into the required gaps, so that's a major head-ache out of the way too. All this is in preparation for finalising the design of the geodetic channel so the extrusion die can be made.

There are three devices that need to be designed and buillt. First is a revised measuring-sled, which measures distance along the jig, and lateral displacement from the centre line. The second is a device to hold and angle-grinder with a cutting disc for the notches in each geodetic member at every crossing of the perpendicular channels. The third is the mechanism for curving the channel to specific curvatures, so that the assembled geodetic channel accurately defines the shape of the tapering fuselage.

So that little lot will keep me busy well into the New-Year. It's exciting to finally be able to move on from the turrets. In the meantime I'm offering one or two new turrets as a commission build, to help finance the next stage of the Wellington. They are necessarily very expensive as the build time alone - some 6-8 months, materials, further vac-forming and around £170 worth of tiny nuts, bolts and machine screws in each turret, needs to be recouped. I doubt many - if any will want one, but it's worth finding out! Ebay item # 184506409292

Further pictures, film and so on as things take shape. Assuming I don't have another turrret to build!

#4542951 - 11/01/20 11:27 AM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Nice to have a project to occupy one during the new Covid Lockdown restrictions here in England! smile



#4542992 - 11/01/20 07:09 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: BD-123]  
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True. It look as if we'll be getting another total lock-down before this bloody disease overwhelms hospitals ability to deal with it. Happily I have a great deal of CAD stuff to do on the Wellington, and a small commission to prepare drawings for a 1930's racing aircraft model, so I can beetle away at both of those in the warm whilst the workshop remains as cold as sin during the winter-months, and all other amusements are off the menu due Covid.

#4543054 - 11/02/20 11:32 AM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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What part of the UK are you domiciled may i ask?
Unseasonably mild but rather 'harry breezers' here in rural Worcestershire.



#4543752 - 11/06/20 06:52 PM Re: FN5 turrets for RC Wellington 1:4.5 [Re: Fidd]  
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Hi BD-123,

We're a bit to the south of you, North Oxfordshire. I'd invite you over but for Covid. I've an old back-injury - legacy of a very high-speed crash where I was thrown clean out of the vehicle, having slid on ice sideways into a ditch at 70mph - so I really feel the cold/wet. Much progress in recent days on the CAD side, and am also contemplating some major changes in the workshop to get the room I need beside the bench for the curving of the extruded channel. So lots to do. It's about 6 years since I made some preliminary drawings of the geodetics and associated fittings, too long ago, it turns out, to remember all the necessary relative dimensions to get the system to work. So it's back to 'trial and error' for a bit! No matter, I'm getting faster at drawing it all again!

Lots of things coming together now towards the fuselage fabrication. Because of the tooling costs for getting the extrusions done, I simply cannot get this wrong, So the strength of the channel, strength of the geodetic framework built from it, resistance to metal-fatigue, metallurgy, weight and ability to curve the channels without deforming the cross-section unduly, ALL of this has to work/be understood, first time. Hence months of work now, and taking advice before this can move even to the prototyping stage. Sorry there's nothing interesting to shew you.

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