Vailly FW 190 1/4.5 (Nick Somerville)

[Denis Watkins]

29 minutes ago, Nick Somerville said:

 

At this point I have no idea how  I am going to cope with sanding the profile around the aluminium inset gun barrel housings ?

 

Pre-prepare lolly pop sticks, with sandpaper glued flat at one end or both

I cut different grades and sandwich flat a number of sticks and sandpaper, wood glued

And when dry, cut excess paper from around the sticks

To make ideal controllable sanding

Edited June 22, 2022 by Denis Watkins

[Nick Somerville]

Some time later working through a fair bit of sandpaper The leading edges are all but done. I have a 40 odd year old Permagrit block that sticking some sandpaper to the curved grip makes for a really useful tool.  The transition at the forward rake was a bit tricky but contrary to my concerns the aluminium cut back nicely. 

 

 

 

 

Just the tips to do and then a final sand all round and I can glass it.

[Charles Hart]

Very nice!

[Nick Somerville]

Been giving some thought to the mounting of the gear/wheel covers, as the supplied collars have screws that do not reach far enough. Added to that they are some US/‘Boris’ thread size. As a work around I have rotated the collars by 180 degrees so that the threaded part is now on the underside and have re tapped them to 3mm. A bit of time perusing BoltWorld on Ebay (highly recommended) resulted in bolts and threaded hex rod sleeves of ideal sizes to allow for some adjustment. Also I like the domed top style hex heads which will look fine on the outer surface.

 

As supplied

 

 

Reversed and fitted with the threaded sleeves.

 

 

 

The threaded sleeves nip up the clamps and there remains about 2-3mm gap between there top and the underside of the covers. I will make up some hard rubber spacers so that there is some shock absorption if the covers get knocked. I did something similar for my Sea Fury and so far it has been effective.

[Martin McIntosh]

The domed head screws are known as button heads and the threaded hex parts are spacers, available in a number of thread sizes and lengths in 2mm increments from places like CPC, very useful.

[Nigel R]

Yup, PCB spacers used in electrical/electronic construction amongst other places.

 

Neat work.

[Nick Somerville]

Used paper templates to line up the hole positions for the leg covers. The holes are drilled a just little oversize and instead of a rubber block, as previously mentioned, short lengths of fuel tubing were cut and slipped over the threads of the ‘button’ heads. This allowed for a precise levelling of the covers as well as giving some shock/bump protection.

 

 

 

In this photo you can see the tubing under compression. Also a closer look will show the piano wire guide lightly glued in place on the lower wheel cover.

 

Once I had checked that the lower cover was correctly aligned and sliding freely behind the upper cover, some spruce was shaped and epoxied in place over the wire to keep it firmly aligned.

 

As I had followed the correct scale outline for the upper covers instead of a rectangular one, as shown on the plan, I had to increase the gap at the top of the covers to allow for the widening taper as the gear is deployed. Still, pretty happy with the fit as this is certainly a challenging part of getting the gear and covers installed.

 
 

[Nick Somerville]

Lower cover inner dressings added. As supplied they had three indentations in the larger part whereas documentation only shows two. Also the lower was not the correct shape. 
 

 

Some lightweight body filler later and they are near enough now for me. You can see that the spruce blocks I made to hold the piano wire part, has almost completely disappeared from this view. Once painted they should blend in nicely.
 

[Nick Somerville]

The wings are off the bench that has now been cleared and I have been looking at how to shoehorn my sizeable Valach twin into the cowl prior to starting the fuselage. When I purchased the engine, on BMFA Classified, I had checked the width of the engine and compared it to the cowl size but the 5mm spare I thought I had is not the whole story.
The widest parts of the engine are of course the rocker covers. I had planned to mount the engine inverted so the rearward carb could sit back in the upper part of the cowl. This would give easy access through a scale cowl maintenance panel for tuning and would require just a little  modification to the top of the engine box.  However in this orientation the rocker covers sit at a point where the cowl starts to turn inwards making my 2.5mm gap on each side a negative 4mm on each side. 

mounting the engine the correct way up moves the offending edges of the rocker cover into the large cowl side blisters so that was a relief. However this puts the carb on the leading edge of the wing just where the single large front locating dowl protrudes through Former 1B.

 

 

 

The answer I guess will be to dispense with the central dowel and instead use two smaller ones bonded to each ribs 1A. I can then enlarge the large dowel hole in 1B to take the carburettor and remove a little of the wing leading edge at the centre to ensure it can breath freely. Access to the carb for tuning will be through the lower cowl maintenance panel.

 

 

Ruler represents wing LE

 

[Ron Gray]

Chopping the wing LE about shouldn’t be an issue as long as replacement strengthening is carried out. I’ve had to do that on warbirds powered by Laser engines to get the fuel tank lower.

[Nick Somerville]

Made a start on the fuselage. Basic box crutch technique with stringers. The projecting light aero ply sides were noted as needing an extra layer of the same 1/16 ply but as these were not supplied I chose to laminate with some carbon fibre and 1mm beech ply. I have left out the engine mounting plate for now but I intend to fit this 20m rearward of the plan position and then mount the engine on short standoffs so that various parts of it are not impeded.

 

In the first photo note the red lines  from the laser helping to square everything up. 
 

In this photo the air tank has been positioned and the fin post has been pinned to a balsa stay attached to one of my wall mounted tool caddy’s. No chance of loosing my square at the back!

[Nick Somerville]

I have been working on the installation of the Sierra tailwheel retract. It’s been a proper shoehorn job and a lot of material had to be fettled away for it to be able to lift up without fouling. To compensate I have added some carbon reinforcement on the outside which will be sandwiched when the balsa skins are added.

 

 

 

Former 9 as supplied and shown on the plan had been positioned for a fixed tailwheel so a new one had to be made and positioned much further forward, also at a slight angle. With the amount of vertical movement at the steering horn this meant finding a suitable run for the pull pull cables was going to be tricky. I have opted for some long slots that providing the cables are spring loaded at the servo end and the cables leading towards the slots have exited guide tubes at a mid point of travel they should not over tighten in either the up or down position.  I will however require a separate servo for the wheel steering that is programmed to switch off when retracted.

 

[Ron Gray]

Looks like a fair bit of weight up the tail end Nick? Very nice retract though!

[Nick Somerville]

You’re not wrong there Ron as including the former and fixings it’s about 5oz. My plan and parts came with the full set of Sierra retracts so seems a shame not to use the tail unit. That said the wheel doesn’t fully retract on the FW 190 and just sits up higher, so if I was really worried about the extra weight I could go for a fixed steerable wheel as per the plan. My Sea Fury has a similarly weighted tail retract and I still managed to achieve a sensible auw, so having spent the effort thus far I shall push on with it and do my best to keep the back end as light as possible to compensate.

[Nick Somerville]

I purposely left out the lower rear stringers as I had read on the Radio Scale Builder Forum that Roy’s plan for the rear fuselage didn’t blend in to the lower trailing edge of the wing correctly and the area behind was not true scale. Trawling through all of my photographic docs and the Bentley drawings confirmed this, even before a trial mating of the wings to the fuselage.

 

 

It’s a substantial error as the formers are pretty thin. However, by blending the required shape rearwards its only really the  former at the trailing edge that needs significant reshaping. 
 

 

I cut the slots deeper to allow the stringers to follow the correct line and have glued them in place. Once set and rigid it should be easy to sand back the formers to the new shape. Further back the tailwheel assembly has been bolted to its former and glued in place. 

[Nick Somerville]

The tailplane has been glassed and glued in place and the basic fin structure built up. As the fuselage is yet to be sheeted some careful alignment checks were made and once again the little level with integral laser proved invaluable.

The tail retract needed a lot of shoehorning as previously mentioned but I am happy with the geometry achieved and the runs for the rudder closed loop and tail steering closed loop have all worked out nicely with no chance of fouling. The elevator is actuated by a very stiff 6mm x 3mm carbon rod. 

The rudder has been constructed and covered along with stitching and pinked tapes as also have the elevators that were made some time back.

The rudder linkage on the full size is hidden with the actuating horn just inside the fin shroud. With a width of only 22mm I just don’t think a closed loop set up will be rigid enough so I have fabricated a small horn giving 40mm between the connection holes that should be fairly innocuous.

Next I need to consider whether a scale access hatch to the tail retract should be made. Even if I do constructed one I think  extracting the retract and air cylinder would be fiendishly difficult so I am inclined to thoroughly test the unit and steering before sheeting the fin, and if 100% happy just simulate the hatch.

[Nick Somerville]

Eagle eyed will have noticed on the previous post that the rudder was missing it’s balance tab. Error addressed and the hollowed addition covered to pretend I had never omitted it.

[Nick Somerville]

I had a feeling this wasn’t a first time offence!!! Same part just a different location.
 

[Trevor]

Slow learner! 😇

[Nick Somerville]

I have had a fiddly few days in the workshop working on what is basically a a couple of pairs of Venetian blinds, or more correctly known in aviation as cooling doors.

I could just have made them static in the open position but I considered working ones was worth a try. The louvres have been made from some curved dowel (soaked in mild ammonia solution) with G10 front and back. The dowels have 1.5mm carbon pins inserted top and bottom for pivots. Behind each there is a horn and an actuating arm connecting the three louvres.   

 

The actuating arms will have a link to either manual rods or some inexpensive servos, yet to be decided.  The key to this exercise is that the doors will be one of a number of routes for hot air to escape the cowl. I have painted the area behind as once sheeted around the louvres I won’t be able to get there later.

 

 

 

Edited August 12, 2022 by Nick Somerville

[Colin Carpenter]

That’s above and beyond, Nick !! 😇😇😇Colin 

[Nick Somerville]

As ever with modelling the second side took a quarter of the time to make up. Holes for the air to pass from the engine bay into the area  behind the cooling doors have been cut and lightweight nylon snakes fitted to actuate the doors. Rather than sheet the area with balsa around the doors I have opted for G10 as thin edges around the openings look more realistic. Also some filling and shaping will need to be done later top and bottom and blending back to the G10 will be easier than if it were balsa.

 

 

[Nick Somerville]

I have started to sheet parts of the  fuselage and wanted to see how the supplied epoxy glass machine gun cover would fit. I happily cut away the flashing back to the clear edge line and then offered it up. Yikes that doesn’t look right, I say to myself, it’s short!  A check at my reference material showed it was short by 23mm, which thankfully was more than the flashing I had trimmed back. If there had been an excess I could simply have blended the moulding line but building up the front was going to be needed now. 

 

 

In this photo the missing front portion is clearly shown with the rear correctly positioned at the hinge line just in front of the raked canopy front. 
 

To add to the front I first shaped some small balsa pieces to continue the final part of the gun blister. Next plastic sheet taped in place and then 3-4 layers of carbon cloth topped with glass cloth wetted out with laminating resin. The first and last piece under/over lapped the front edge by 5mm.  
 

 

Under the gun hood, that will have a scale hinge, I plan to mount battery switches, the air fill valve and Ignition kill switch and possibly the ignition unit too.  

[Nick Somerville]

Here is the now extended gun hood. Still a little more fill, sand repeat to go but getting there. 
 

 

This is a photo of how the inside of the real hood looks.

 

 

and this is where I am at the moment after some serious faffing about. Fortunately the only time it will actually be seen is when opening to access switches etc. 

 

[david tilbury]

Hi Nick,

 

Great build!.....love the work on the flaps and cowl vents....great to catch up on the phone earlier....look forward to seeing the 190 come together

 

All the best

 

Dave