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Baby Bus - Winging it!


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Converting Revell's Airbus A319 into an Airbus A318

I've seen several attempts at doing this conversion, they've involved chopping sections out ahead of and behind the wing, and increasing the height of the tail. Whilst this is in escence correct, it doesn't deal with several other differences that have been glossed over or ignored, and all the conversions I've seen involved filling all the cabin windows - all my other baby busses have open windows and I wanted to keep them open on the A318 if possible.

So, after much mulling over and drawing lots of lines on the kit parts, I've finally got round to chopping up the kit.

I'll say straight up, I wouldn't recommend this as a first attempt at an airliner cut'n'shut!, but if you've done a couple , can get your head round the marking out, and can make accurate neat cuts, it's not too difficult.

Here's the fuselage halves with my rather overcomplicated plan drawn out on them - follow the notes if you're attempting this as I'd do things slightly differently if I did this conversion again!

IMGP5750.jpg

Firstly, you may notice a vertical line through the front of the wing root fairing on both sides - ignore this, it was part of plan A and ended up having to be filled as I'd scored the line in position.

Secondly, the aft upper section can be cut out directly above the lower section, at least on the port side, which will simplify things somewhat.

So, how much to cut? We need to loose 2.4 metres from the A319, 1.6m aft of the Wing and 0.8m in front, which equates in 1/144 to 11.11mm and 5.56mm. This equates to 3 frames (windows) aft and 1.5 frames forward ( 2 windows, outer edge to outer edge)

The aft three windows can come out anywhere aft of the roof aerial (if you want to keep it, it looks to retain the same position 319-318).

To retaiin the correct window spacing the forward section has to come out where shown ie the 7th & 8th windows from forward have to be removed.

This is all fairly straightforward down to the window line, but gets more complicated for the lower fuselage, as this takes in the wing root fairings, and the cargo doors, which are modified on the A318.

Taking the port side first, as it's easiest, the forward lower section is taken out immediately in front of the wing root fairing, use dividers to ensure the upper and lower sections are the same length. The aft section would be best cut as one section, with the aft edge immediately aft of the wing root fairing. Measure 3 windows forward, and remove this section EXCEPT for the wing root fairing, score round this and remove the body tube.

The starboard side is more complex if you want to retain the cargo doors. These were reduced in width to 1.3m (9mm scale).

The forward edge of the forward door remained in the same place, so mark 9mm aft of this and scribe vertically up to the window line. Scribe another parallel line at the front of the wing root fairing. Measure this distance and subract from 5.56mm (fwd reduction). Use the result to measure forward from the wing cutout, and scribe up to the top of the wing root fairing. Scribe another line parallel to the window line at the top of the wing root fairing forward to the waste section previously marked. This wil result in a shortened wing root fairing which sits up against the forward cargo door.

The aft door moved aft one frame, so two parallel lines, 1 frame (window spacing, 3.7mm) apart need scribing immediately aft of the aft door up to the window line.

Mark the door width (9mm) from the aft edge of the door and scribe a vertical line up to the window line, EXCEPT over the wing root fairing. Mark another parallel line 2 frames (window spacings, 7.4mm) forward, again not on the wing root fairing.

Score the vertical lines and finish the cuts with a fine razor saw. Score the horizontal lines, and fold/snap the parts in two. Score and snap away the waste plastic around the wing fairings. You should end up with a set of parts similar to below.

IMGP5755.jpg

Next installment - sticking it all back together.

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Chris

The hardest part of the conversion so far was workingout how to write it up in a semi coherant manner. Working out the plan of attack wasn't too difficult (though it did change a bit between drawing on the plastic and actual cutting, and as noted, I'd do it a bit different if I did it again) The actual cutting and sticking back together is fairly straightforward if you can cut accurately.

Andrew & Feofee2

Sit back and enjoy (but be warned, my projects can drag on and sometimes get sidelined....)

POTKC & John

She'll be finished as G-EUNA or G-EUNB, one of BA's transatlantic bizjets.

MikeW

I can do rocket science - brain surgery on the other hand.....

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Chris

The hardest part of the conversion so far was workingout how to write it up in a semi coherant manner. Working out the plan of attack wasn't too difficult (though it did change a bit between drawing on the plastic and actual cutting, and as noted, I'd do it a bit different if I did it again) The actual cutting and sticking back together is fairly straightforward if you can cut accurately.

.

Thanks Dave.

I know what you mean regarding the write up. Always more difficult to describe the process for someone to follow than it is to actually carry out the task.

John and I were only discussing the topic of cabin windows and ways to retain the kit glazing the other evening so I'm hoping you have some bright ideas to share when it comes to the masking up process.

All the best.

Chris.

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Chris

Nothing revolutionary with the window masking - I create a mask out of tamiya tape for the whole cockpit window section based on the kit window decal, then add the windscreen vertical bars from strips of painted decal film once the mask is removed. Cabin windows I glaze with a strip of clear decal film. I'll post photos when I get to that bit...

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it doesn't deal with several other differences that have been glossed over or ignored,

Hi Dave,

Nice conversion on Airbus's "cocktail sausage single aisle". I had one under work a few months ago but bizarrely lost courage after completing the fuselage, which is the most difficult part of this conversion.

I notice your rear W/F fairings are untouched, they are IRL shorter & connect to the rear fuselage in a less fluid way.

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Welcome back for part the second, and thanks to Steven for his timely comments above.

He's right on both counts, converting the fuselage is the hardest part, and the rear of the wing /fuselage fairing is shorter and rounder on the 318 than the rest of the series.

Fear not, I'd not forgotten this, as dealing with the aft sections of the wing fairings is next up on the agenda.

So, taking the two centre fuselage sections I chopped out yesterday, the first job was to rough out the shortened fairing. I don't have precise measurements on this, but working from internet photo's (Airliners.net etc) they look to me to be 1 frame (window spacing) shorter, which is 3.7mm in this scale. this distance was measured forward of the old fairing line, and a new fairing curve marked in as shown below.

IMGP5758a.jpg

Once happy with the curve, this can be cut and filed to shape.

The arrows mark the next stage, which is to thin out the inside of the fairing to allow the aft body section to slide snuggly inside. The bottom section is relatively easy to do with a half round file following the line of the bottom of the fuselage inside the fairing. The upper section is a little more difficult as you have to form a step inside the fuselage which follows the vertical cut up to the window line. A curved scalpel blade and gentle scraping will achieve the desired result in a few minutes. A burr of sanding drum in a dremmell or similar would no do the job faster, but for me the risk of taking great big lumps out and having to rectify the damage greatly outways any potential advantage.

With the inside of the fairing opened up to allow the fuselage body to sit snuggly inside, the outside of the fairing can now be smoothed out at it's aft end to remove any remaining step where it meets the fuselage. I was left with a small (0.5mm) gap around the extreme aft edge which was easily filled with putty once the fuselage halves were re-assembled.

With that done we can think about re-assembly of the fuselage parts. My method is to re-assemble one half of the fuselage flat on a piece of glass (to ensure no bend or twist in the vertical plane) and against a steel rule to ensure all is straight in the horizontal plane. I used chopped up bits of the waste sections removed yesterday to make tabs at the top and bottom of the vertical cuts, taking care not to obstruct the windows. These were stuck in position with superglue and allowed to set for a few minutes before test fitting of the parts.

I started assembly with the port fuselage half, as this is the easiest, and also doesn't have the locating pins so will lie flush on the glass. The nose and centre section were joined first by sliding the sections together on the glass and checking horizontal alignment along the top of the fuselage and on the window line. Once happy with the alignment I put small drops of superglue into the joint at two or three points along the joint, check alignment and then drop accellerator on the superglue to fix it. give it a few seconds to bond and the two joined sections can be removed from the glass and checked from all angles. The small drops of superglue should be strong enough to hold the joint in position whilst you check, but weak enough to be broken apart if you're not happy with the alignment.

For applying superglue I use an old darning needle with the top of the eye ground off to leave a fork. I put a drop of superglue onto an old foil container, and dip the forked end of the needle into it to pick up a bead of superglue, this can be accurately positioned on the model. It can also be used in a similar fasion to a lining pen to fill seams and join lines, as the glue runs from the reservoir between the forks as the needle is drawn along the join line.

If you're not happy with the alignment, break apart, re-adjust as necesary and try again.

Once you're happy with the joint, the rest of the join line is filled with a bead of superglue as described above. If the joint is to be a panel line I aim to leave the bead slightly below the surface, if the join is supposed to be flush I aim for a slightly raised bead.

With the superglue bead in position I next run in accelerator from the side of the bead by careful positioning of the brush loaded with accelerator and the angle that the joint is held at. Not touching the bead means the bead is not disturbed, and more importantly, the brush doesn't become permanently attached!

The joint should now be filed and sanded flush fairly quickly, whilst the superglue is still relatively soft. If a panel line is desired along the joint, run a fine razor saw along the line and clean up with a P cutter or similar. Large joints are best tackled in sections to ensure alignment and to enable smoothing to be completed before the superglue sets up too hard.

With the port front and centre sections joined satisfactorily, the aft section is joined to it in a similar manner.

Now comes the slightly more tricky starboard half, as you have 5 pieces to join here instead of 3. Firstly the completed port half was checked yet again, then the nose and tail of the starboard half were offered up and held in place with masking tape. With these held temporarily secure in their correct positions, the centre section can be offered up. Don't force it, as if it's slighly too long this can introduce an bend in the fuselage. It should be an easy sliding fit (and preferrably not a rattling good one!).

Once happy with the centre section fit, it was removed and the aft cargo door section was offered up and very lightly tacked in position. The centre section was again offered up and the aft cargo door section tweaked into alignment. This is probably the most difficult section to align, and it took several attempts with minor fettling in between, before a good join was achieved. The cargo door was fully joined to the aft section before the aft and centre sections were joined. Don't forget to fill and smooth each seam as you go!

With the aft and centre sections complete the forward fuselage was joined to the centre section, and lastly the shortened starboard wing/body fairing was fitted. Having the wings assembled (just the top halves attached to the one piece bottom half) will help here for checking the fairing alignment to the wing section.

You should now have two complete fuselage halves as per the kit, but now shortened to A318 length, and looking soemthing like this:-

IMGP5759.jpg

More tomorrow.

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A bit more today. The next bit is pretty much conventional kit construction. I sprayed the insides satin black, and added an M12 brass nut to the top of the nosewheel bay for ballast, secured with epoxy glue. Once the glue and paint was dry the nosewheel bay was glued into one half, and the other half was glued on and taped up to keep the seams closed. I used Revell Contacta for this, and left it to set up overnight. With the glue set, the seams were given a onceover with sanding sticks, and any minor imperfections filled with putty. The wing tops and bottoms have been joined, the extra double slot flap fairings for the A321 sliced off, and the double slot flap lines filled in.

IMGP5760a.jpg

Next up on the agenda was the other noticable feature of the A318, the extended tail fin. I started by slicing off the top of the fixed part of the tailfin (not the rudder) at the topmost panel line - this gives a nice flat top to the fin to which the extension was going to be attached. The extension is 0.7m (4.86mm scale), to which I had to add the 2mm already trimmed off the top of the tail. A strip of 2mm plastic card 7mm wide was duly cut and squared up, then a notch was cut to accommodate the rudder, this was test fitted and adjusted to fit in position - don't worry about overlap fore and aft at this stage, this will be dealt with once secured.

IMGP5761.jpg

To ensure rigidity once secured, the top of the tail was drilled to take a couple of short lengths of 0.8mm brass rod. The positions of the holes was transferred to the extension block using dividers, and two similar holes were drilled in this too. The holes should be roughly perpendicular to the top of the fin and on the fin centreline, a small amount of misalignment can be taken up by dry assembly of the rods and extension, then gentle bending of the rods and extension to get the final alignment. Once happy with the alignment move the extension up a fraction to enable superglue to be flowed into the joint, then push back into position and re-check alignment.

IMGP5762.jpg

With the superglue set, the leading and trailing edges of the extension can be cut to size, and then the fin extension filed to a matching aerofoil shape. I use double sided tape to tape the fin to a suitable sized wood block, with the edge being worked on aligned with the edge of the block. The fin is supported along it's length by the block which is held down on the workbench, whilst the extension is attacked with a large (10") medium single cut file. This might sound excessive, but it makes short work of the amount of plastic to be removed, and if done with care won't damage the rest of the fin - if in doubt cover the fin with a layer of masking tape. The fin has to be removed and re-attached to the block to finish each edge (port leading, port trailing, stbd leading and stbd trailing edges), but it's a quick process taking less than 5 minutes to do. Once it's filed to the basic shape, it is given a polish with sanding sticks to remove any file marks and blend it into the original fin. Any lost panel lines can then be re-scribed, and you should end up with something looking like this:-

IMGP5764.jpg

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Glad you like it so far Chris - if my waffle gets a bit ambiguous, please shout up!

Currently playing with modding the CFM56's - very rarely mentioned and applicable to the whole A320 family (except the IAE V2500 powered ones of course)

Next installment tomorrow afternoon

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Yesterday we fixed the tail, today we move on to the nose.

IMGP5765.jpg

Here I've done a bit of filling and re-scribing, especially around the cargo doors, and filled the forward two windows on both sides. The window gaps were filled with superglue, a drop of accelerator added and the outside filed and filled to blend in with the fuselage side. The cockpit glazing has been added as well. This is an area that can be greatly improved on any revell baby bus, easy if you're using decal windows, but a little more involved if you want a clear windscreen.

IMGP3347.jpg

Apologies for the slightly out of focus shot, but this illustrates the difference between the Revell glazing as supplied and a much improved look with a simple modification. On the left, the kit glazing doesn't quite fit the aperture, leaving an ugly seam line; and if the engraved lines on the glazing are followed the windows end up being too small, giving the whole front end a squint or frown.

To eliminate this, first dip the glazing in Klear (future or similar acrylic gloss varnish), as we're going to fix it with superglue and this will prevent the inside fogging up. Once this is dry, the glazing is slipped into the aperture, and one side is juggled so that it is flush with the fuselage side. A small spot of superglue is then run into the aft edge of the glazing to hold this position - don't glue the top and bottom yet. When dealing with glazing and superglue, I find it best not to use accelerator as this can cause it to discolour, so best to be patient and let the glue set up for a few minutes. Once set, the other side of the glazing can be teazed out to lie flush with the fuselage side. Gentle finger pressure on the forward side of the glazing on the same side that's been stuck, together with a bit of gentle levering with the point of a scalpel blade between the other aft edge of the glazing and fuselage can be used to pull the glazing out flush, once in position gentle pressure on the front of the glazing will hold it in position whilst a spot of superglue is used to secure it. The operative word here is "gentle" - if you're hamfisted here you can end up cracking the glazing. Once the aft edges are secure, superglue can be wicked into the rest of the joint to seal it in position. It needs to be secure, because the next stage is a bit drastic, it's out with the file again.

IMGP5767.jpg

I have a smaller medium cut file I use for this, and the object is to file the glazing so that the engraved windows are just removed. Tthe trick here is to keep the file flat on the windows without rocking it, so that the windows and the surrounding fuselage don't become curved. Work vertically on the side windows first, then horizontally across the two windscreens taking a bit at a time off each to maintain symetry. Stop as soon as the engraved windows disappear, then switch to fine sanding sticks, then polish with micromesh.

IMGP5768.jpg

You now should have something like this - so clear you can hardly see it!

I fitted the wings last night, and another minor filling and re-scribing session followed after they'd set.

IMGP5770.jpgIMGP5771.jpg

On the left is the modified A318, with the assymetric forward wing root fairings, shortened aft wing root fairings, and the removed and faired double slotted flaps and fairings only applicable to the A321, which is seen from a previous build on the right, complete with standard wing fairings.

Here's a great photo of the prototype A318 from directly below which shows the altered fairing shape pretty well (especially the assymetric front fairings) I think I'm pretty close with my rendition - what do you think?

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Today I'm going to look at Baby Bus CFM56 engines, as, for modelling purposes, they come in two different flavours - CFM56-5A's and CFM56-5B's.

The CFM engines in the Revell kits are pretty good renditions of the CFM56-5A, and for most medellers I'm sure they're good enough for any CFM powered baby bus, however AMS inflicted airliner modellers will want more accuracy.

As can be seen here, the CFM56-5B gives significantly more thrust and less emissions than the 5A, which it superceded; and to do this it had an extra LP compressor stage, new fan and a longer fan case. In modelling terms this means a slighty longer nacelle, the extra length being at the front of the nacelle.

This shot of a CFM56-5A shows the shorter fan inlet casing and engine doors - note the position of the front of the door behind the pylon nose.

This shot of a CFM56-5B shows the longer fan inlet casing and engine doors - note the positionof the frontoof the door in front of the pylon nose, and the wider section between the door and intake ring denoting the the longer inlet casing.

If you're modelling a CFM56 powered A321 or A318 it will have the longer nacelle 5B. If it's an early series A320 or A319 it would have originally been fitted with the short nacelle 5A, whether any were upgraded later to the 5B I don't know - BA's CFM powered A320's all appear to have retained the 5A. Later series A320 and A319 all have the 5B fitted - as usual check your references for the aircraft you are modelling, now you know what to look for.

So, how to model the longer 5B?

I started by cutting off the fan intake casing flush with it's aft edge inside the casing (ie where the fan recess is inside each nacelle half) using a fine razor saw.

After filling the ejector pin marks on the insides of the nacelle halves, the aft sections were built as per kit instructions, the forward intake casing halves were joined, and after the locating lug on the back had been removed, the two fans were glued to 1mm plastic card (offcut from a Welsh vacform - well I am a Yorkshireman by upbringing, waste not want not as they say).

IMGP5760b.jpg

The intake casings can now be filled and faired in on the internal joins, and the card backing cut from around the fans and the edges filed round so that they are now 1mm thicker. I'm not going to get into blade count or shape, the fan discs will be used as is - if you want to improve these please feel free to post how you've done it! The fan disc was then glued centrally to the back of the inlet casing, then once set this was offered up to the rest of the nacelle and glued in place. Use the remains of the pylon front to assist in alignment.

IMGP5772.jpg

Modified lengthened 5B nacelle at top, 5A kit nacelle below

Once the glue had set, the remains of the pylon were removed from the top of the inlet casing, and the circumferential gap filled with milliput and smoothed out. Whilst doing this mould a new pylon front fairing in position. After setting overnight the milliput and nacelle can be further filed and sanded to achieve a smooth fair line - just filling the gap leaves a parallel step that needs fairing in, a few minutes work with file and sanding sticks.

IMGP5773.jpg

And after shaping they look like this - I've just noticed I've rescribed the front of the engine door line exactly where the kit line is, this should of course be a bit further back, so a little more filling and scribing to do yet.

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Thanks for a masterclass Dave

I am looking forward to this but I have the eastern express kit to save having to cut the revell kit down
Thanks

If my experience is anything to go by following Dave's methods will be easier and give a better result than trying to make a decent model out of the heap of :shit: in the Eastern Express box

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Thanks for a masterclass Dave

If my experience is anything to go by following Dave's methods will be easier and give a better result than trying to make a decent model out of the heap of :poo-poo: in the Eastern Express box

The kit does not look great but for £18 I'm at least going to try. Lol :)I think it is the revell kit cut down but very poorly.

Dave's method is looking great so may take some inspiration.

Thanks

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I haven't seen the Eastern Express kit, I did hang around putting off the conversion until after it was released, and once I'd read the reviews on it I decided to pass. If you're already got the kit and fancy building it I'd be interested to see how it compares.

Well today I've been wasting my time on't interweb reading Britmodeller and looking at pictures on Airliners doing some serious research into baby bus wingtip fences. I came across this thread started by feofee2 with some very helpful contributions from XV571, including a dimensioned drawing. This was both a huge help and headache. I traced the drawing in coreldraw, and tried sizing it to the dimensions but this resulted in a severly distorted shape (squashed horizontally). Next I tried superimposing the outline as drawn on various photo's of the tipfences. Allowing for distortion due to camera angles etc, the shape as drawn by XV571 looks spot on, so keeping the proportions the same I juggled around with the size and dimensions and came to the conclusion that he's got a couple of them wrong. If you move the reference for the 855mm line, the rest of the dimensions fit except the 100mm at the bottom. Rescaling the drawing gives the following corrected dimensions:-

Tipfence-1dims_zps86a45d0a.jpg_original.

With the shape and dimensions sorted, it was then easy to rescale this to 1/144 and copy it, then export the file for use. Below is a jpg version of XV571's tipfences to scale, if you're printing it out to use as I did, make sure it's printed at 1:1, some picture programs "helpfully" resize images to fit the printed page!

Baby_Bus_Tip_Fence.jpg

The next step was to cut a strip of 0.5mm plasticard approx 12 mm wide, then two tipfences from the above drawing were cut out and stuck on one end of the strip using double sided tape. These can then be cut out using a new scalpel blade and a steel rule as a guide. Don't try to cut through the card in one cut, in fact you don't need to cut all the way through at all. Gently cut through the paper and lightly score the card with the first cut, deepen the cut with a couple more gentle cuts, then snap the waste section off. I did the bottom curved cut freehand first, then cut the V out of the back edge with two cuts, 1 snap, then trimmed the rest with single cuts right across the strip until the part falls away.

Peel off the paper outline, and you've got a blank. Round the leading curved lower edge with a half round needle file, round the top leading edge with a flat needle file, then file the sides of the aft edges to reduce the thickness to sharp edge.

They're a little fiddly to hold, but I'd finished two off and cut out another pair in the time it's taken me to type this.

IMGP5777.jpg

From the left, 2 tipfences stuck to the strip, 2 tipfence blanks cut out (top with paper template, bottom without) 2 tipfences filed to shape - they still need a bit of a polish with sanding stick yet, and one of the undersize kit tipfences.

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Dave.

Thanks again for the serious amount of effort you're putting into this one for our benefit.

I'm really impressed with the way that fuselage has turned out, and the engine work you have done will make life easier for many of us wishing to undertake similar steps to improve the Revell kit.

I hope you don;t mind if I save it all for future reference.

Chris.

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Glad you're enjoying it Chris, and please feel free to download & save what you want, thats what it's there for.

Progress will grind to a halt as of tomorrow as I'm off over to my parents for a week, however if anyone is interested I'll have the model on the Wakefield stand at the Huddersfield show on Sunday. I'll be on the Competition check-in desk most of the day if you want to say Hi. Building will resume once I'm home, assuming I'm not distracted by a "must build" picked up on Sunday!

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