John Woodfield PSS Hawker Sea Hawk

[Saint 1]

For some considerable time now I have been trying to ween myself away from building in Correx and had promised a certain Mr. Cooke that my next build would be something in balsa. I had no excuse really because residing in my garage there has been a rather large box full of balsa that some time ago was very generously donated to me by a fellow flying friend. 😁

 

Although I have built extensively in Correx I have to say that my experience with balsa is somewhat limited so I have much to learn. The only real wooden kits I have built to date are a rubber powered Stuka about 50 years ago and a Veron Vortex slope soarer….and that had a glass fuz! Wisdom would have me building something tried and tested by the PSSA masses such as the mass build Jet Provost or Hurricane but no, that would be far too sensible. For some time I didn’t really know what I wanted to tackle, until one rainy afternoon a few weeks back when I found myself watching YouTube videos and happened upon those of John Woodfield RC Gliders. There I saw his own design Hawker Sea Hawk, an aircraft I was instantly drawn to and one which looked to fly remarkably well in John’s hands. Incredibly for its size (1/8th scale) it only weighed 1.3kg, not at all dissimilar to most of my previous and yet smaller Correx builds so it shouldn’t require a howling gale to get it airborne.

Half an hour later I had purchased and downloaded the plans and build guide from Gliderworks! There are 2 sheets of plans plus a 22 page build guide.

 

 

 

The very first sentence of that build guide states “This balsa model aircraft plan is aimed at the more experienced modeller as the airframe is a relatively complex shape to construct” so I know I’ve set myself a challenge. Nonetheless I will give it a go and hope I will be able to draw on the vast wealth of knowledge and experience on here to guide me along the way. Thanks must go already to Harry Twist for his help and advice regarding tools and build boards. 👍

At 1/8th scale this Sea Hawk has a 1.5m span so quite compact but until I got some full size prints done I hadn’t fully appreciated just how long 1.5m is for a fuselage!

 

I haven’t been able to find any previous builds of this particular Sea Hawk anywhere online but would have thought there must be a few built and out there somewhere by now so if anyone knows of someone with one I’d be interested to hear how they got on with building it. The only Sea Hawk build I did come across was a smaller version designed by our very own Andy Meade.
For me and I would think many more too there is a fundamental flaw with these plans in that it is a one-piece aircraft so not at all easy to transport. I will therefore being making life even more difficult for myself by making the wings of my model detachable, in a similar position to where the real wings fold up. My thinking at the moment is to use a telescopic carbon tube arrangement on the main spar with a second smaller bar/tube in line with the false trailing edge, assuming I can source them in the right sizes that is but would welcome any suggestions on the best approach.
At just 1.3kg I believe John’s version must have been built almost entirely from balsa and covered in a lightweight material. He also didn’t choose to incorporate a rudder. I am expecting mine will be considerably heavier but will keep weight down wherever I feel possible; I am using 3mm ply for all the fuselage formers plus those wing ribs that will be supporting the carbon joining tubes. I will probably include a rudder and will definitely be covering it in glass cloth – which will be another first for me.

There are one or two grey areas with the plans so I am hoping to get these clarified with John at some point but not enough to stop me from making a start. 😁

I cut out paper templates of all the fuselage formers, transferred them on to the 3mm ply and then spent the best part of a day cutting them all out.

 

 

 

 

Once cut out I then had a look at trying to save some weight and with the help of one or two spade drills and a Dremel managed to save 24g. It doesn’t sound much but it’s the weight of a couple of small servos.

Having got myself a piece of plasterboard I placed the fuselage plan onto it and covered it with a piece of polythene and then commenced with pinning the ‘keel’ piece in place. I had previously soaked the keel in hot water as best I could and squirted it with a steamer for good measure to help it bend a little more readily.
Once that was dry I was then able to start piecing the tail together. Having read a few of the mass builds I opted to follow the ‘in-house style’ by make the leading edge of the tail fin by sandwiching a piece of thin ply between two pieces of balsa.

 

The last job for today was to glue the fuselage formers in place, it was a good job there were only 14 of them because I was starting to run out of things to use as squares 😄

 

 

 

So that is where I’m at, much more to follow! The next job will be to add the longerons.
 

[Phil Cooke]

Great to see you underway with this Phil, and a superb, considered choice I think - It looks like you are making great progress too - some lovely shapes in those formers! 

 

'Double check your grain direction' and 'keep your scalpel blade sharp' would be my advice in this 'new' material and you will really enjoy working with balsa im sure - give me a ring anytime if you have any questions.

[Saint 1]

Thank you Phil and thanks too for all your help and advice today, it is very much appreciated.

 

I managed to make a little more progress on the build today by splicing the longerons together and installing the two left hand side ones which firmed the formers in place nicely so I'm leaving that to set until tomorrow now. I was then able to remove all my supporting 'squares' bar one which I seem to have built in until I remove the fuz off the board 😄

 

 

I also started to have a think about servo placement, I'm still undecided on whether or not to include a rudder.

 

 

[Saint 1]

After removing the fuselage from the board I was then in a position to start assembling the RH halves of the formers on to the central spine. I found bulldog clips ideal for keeping the 2 halves in line and also found some of the lightening holes I had added previously had the added bonus of acting as clamping points.

 

 

 

 

 

I had to make a temporary support to ensure the stage 3 former was set correctly.

 

 

Once those were all dry I then carefully fitted the two RH side longerons doing my best to ensure everything remained square and true. To help with this I used my digital callipers to check the spacing between former stages was equal side to side.

 

 

 

The next job on the list was to fit the fuselage sole plate which is made from 3mm balsa. I had to fabricate this in 3 parts in order to be able to slide it into place; a straight central section with a locating tongue on the front end plus two tapered side strips.

 

 

 

The forward tongue locates in the stage 2 former

 

 

The final job for today was the canopy base which I opted to make from 3mm ply rather than balsa to make it more robust, seeing as this will form the radio gear access point. It is made in 3 pieces. After cutting out the paper templates I marked them out on to the ply, cut them out and somewhat pleasingly found they all seemed to fit with very little additional fettling.

 

 

 

So that’s page 6 of the build guide now complete…16 more still to go.

The next little job will be planking the lower fuselage up to the lower longerons so that'll be something new for me 😁

 

[J D 8]

One of the best looking early jets made, good luck with this one.

[Saint 1]

It was planking time, but before I made a start I was in need of a support cradle for the fuselage, it was so delicate at this stage I felt sure I’d probably inadvertently break something if I didn’t. Suitably inspired by one Phil had made for his Sabre I found out some pieces of foam and wood and knocked something up, supporting the fuselage on the stage 4 and 11 formers.

 

 

The build guide suggests planking the fuselage with 1.5mm (1/16”) balsa. I felt this to be a little too delicate for where we fly and in addition thought it would also leave me very little material to play with if I was to be able to finish sand the fuselage to a smooth profile rather than a '50p effect' one. Discussions with Phil Cooke affirmed my thoughts and so I opted to use 3mm (1/8”) balsa instead.
I wasn’t sure whether there was a right or wrong way to go about the planking but decided to start by laying a narrow strip along bottom dead centre and then working outwards from either side….but then changed my mind 😁 I wasn’t quite sure how to taper all the ends towards to the tail so decided to run a strip along either side at the point where the wing fairings would blend in with the fuselage body and then work back up from there.

 

 

This seemed to work out ok so I continued to alternate fitting planks from either side and bottom dead centre and tapered them into one another at the tail in a sort of herring bone pattern.

 

Generally the planks varied from anything up to 10mm at their widest down to 2mm at their narrowest.

 

 

 

It took a bit of fettling to get the final pieces in but nothing too bad and once they were in I then added a couple more planks on either side until the lower longerons were covered.

 

I’ve never built anything in matchsticks but I reckon the front end is starting to resemble something along those lines.

 

 

 

 

 

 

At this point the guide suggests putting the fuselage aside and making a start on the wings. Before I do that though I need to get clear in my mind precisely how I’m going to construct them, make them detachable and retain them in flight. There will be no access to the wing roots within the fuselage, unless I choose to create one, so I am continuing to think along the lines of a carbon tube arrangement with magnets on the wing to fuselage interfaces in order to retain them...
 

[Saint 1]

Just a little update on where I am currently...

 

These are the next two stages in the build guide

 

 

 

Note how the upper and lower spars extend inboard - ordinarily this would be to attach the wings to the fuselage former but since I am making my wings detachable I will be creating a joint at rib 2. This looks to be in a similar position to where the real aircraft's wings fold up.

 

I managed to find some nice carbon tubes from Hyperflight.co.uk - the main wing spar tubes telescope together smoothly with very little discernible play. The outer tube is 13.80mm OD x 12.00mm bore. The inner tube is 11.80mm OD x 10mm bore.

 

 

My initial thought had been to leave the inner tubes free-floating and rely on magnets to keep the wings in place in flight. The plus point of doing this would be that the inner tubes could easily be replaced in the event of damage. The down side is hoping the wings don't detach in flight!

I have since decided against that thought however and will likely adopt a more secure method of wing retention, along the lines of a very neat idea that Phil Cooke came up with. The down side of this method is that the inner tubes would need to be bonded within the wings but then, where they slide within the fuselage it should be possible to have a sacrificial nylon bolt that passes through both inner and outer tubes. This bolt would positively secure the wings and with a little careful planning should be accessible through the air intake on the wing leading edge.

 

There is no mention of any wing washout on the plan but after more guidance from Phil and Harry (thanks again chaps!) I have decided to build 1.5 degrees in by making tapered supports for the false trailing and leading edges. Another deviation I will be making is by upping the balsa sheet thickness for the wing covering from 1/16in to 3/32in, primarily for greater strength but also to avoid having too thin a trailing edge.

 

 

I have made the ribs supporting the carbon tube from 3mm ply and left the rest in 3mm balsa.

I have locally increased the width of the upper and lower wing spars from 9.5mm to 14mm in order to match the carbon tube OD, that way I will then be able to fit shear panels front and rear, boxing the tube in place. I intend filling the void around the tube with filler - my current thinking is an epoxy resin / sawdust combination but I'm open to any better suggestions.

 

 

(The two most inboard ribs will form part of the fuselage and are out of position in these photos)

 

 

 

Nothing is glued as yet as I am awaiting delivery of some MPX connectors and servo leads plus I also don't have any spare suitable wing servos to hand just now. I have used Corona servos in many of my previous Correx builds and been highly suited with them so plan on using their DS-843MGs for the tail surfaces (very light at only 11.5g) and then DS-239MGs for the ailerons. In all cases I want to try and make discreet access panels, should I ever need to replace one in the future, so that's something else requiring some thought. I do have some exceedingly small screws, some of which I have used previously to retain canopies, so I may be able to use those again this time to secure the access panels in place.

 

 

 

[Saint 1]

After sourcing some MPX plugs and suitable wing servos I was able to make a start again...

I carefully cut rectangular holes to take the male and female plugs, making sure they aligned nicely, after which I started gluing things together. I glued the ribs to the lower spar and false leading and trailing edges, followed by the upper spar.

 

 

 

 

I built the main wing and the stub wing (that will form part of the fuselage) as one with the upper and lower spars holding everything together.

 

 

I plan to finish the wing joint faces with skins of 0.8mm sheet ply so I made some temporary 1.6mm balsa spacers to maintain the necessary gap. I slid both carbon tubes in place to make sure everything was aligned.

 

 

It seems that Robart hinges are the hinge of choice so after yet more help from Phil I ordered some suitably sized 1/8" ones and glued in some balsa blocks to accommodate them.

 

 

I had already decided to move the aileron servo in by one bay from the position shown on the plan as it would bring the weight further inboard whilst still having the control horn reasonably central in the aileron. Conveniently this also made room for the centre Robart hinge.

 

 

 

I glued 1/16" balsa shear panels to the rear faces of the spars along with those along the front which didn't conceal the carbon tube as I still need to fill those bays and then added a block of balsa to blank the end of the carbon tube off.

 

 

At this point I thought I would have a look at how the wing was going to fit with the fuselage.

It was necessary to cut away the fuselage sole plate in order to allow the lower spar to reach the fuselage centreline.

 

 

I could have cut the lower spar short to avoid cutting the sole plate but chose to keep its full length instead and maximise the glue joint being the spars and former. I cut the slot a little larger than the spars width to allow for the forward shear panels once fitted.

 

 

 

 

Seeing as the wing is mounted mid way up the fuselage I have decided to have the aileron control horns on the underside so with the wing upside down I positioned the servo to be in line with my planned aileron horn location and made up a servo tray from some 1/8" hard wood I had in my stocks.

 

 

 

My plan is to leave this bay fully open when I skin the underside, after which I will then make a frame within the opening and sit it slightly underflush from the skin by the thickness of my servo cover which I intend making from 0.8mm ply.

 

I glued three little noggins of 3mm ply on the upper side to give the servo screws something to bite in to.

 

 

It's all a bit steadier than building in Correx but more precise and everything seems to be moving in the right direction at least. 🙂

[Saint 1]

Progress has slowed a little what with one thing and another, not least of which being our recent Orme excursion for the Dambusters 80th but I've now managed to move things on a bit again.

After sourcing some 1.5mm fibreglass sheet I made an aileron control horn and glued it to one of the ribs with a little balsa web for extra support.

 

 

 

The next job was to fill the void around the carbon wing tube in order to support it and spread the wing loading more evenly. I did this with a mix of epoxy resin and sawdust mixed in a ratio of 25% resin / 25% hardener / 50% sawdust which seemed to do the trick.

 

 

 

I supported the wing in my workmate and pushed the filler in to the voids either side of the carbon tube until it was flush/slightly overflush with the two wing spars.

 

 

 

Once that was dry I sanded it flush where necessary and then added the remaining balsa shear panels.

 

 

 

Finally I was in a position to sheet the lower surface of the wing and aileron. I am using 1/8" sheet for this rather than the 1/16" (1.5mm) suggested in the build guide. I glued some sheets together and then cut the wing and aileron surfaces out slightly oversize. I also cut the hole for the aileron servo opening, again I left a little extra material on here too for final dressing once assembled.

 

 

I sanded a taper along the trailing edges of both wing and aileron using my Permagrit sanding block and a piece of wood as a guide. This taper, along with a similar one on the upper skin in due course will allow the two skins to come together and form a neater trailing edge.

 

 

Another thank you here to Harry Twist for recommending the Permagrit sanding block to me, I don't know how I ever managed without it! 👍

 

 

I used anything heavy to hand to ensure the ribs and skin were kept in close contact until the glue had set.

 

 

 

 

The lower skin of the stub wing required a small cut-out to clear the stage 1 rib which is larger due to it being within the faired section where the wing meets the fuselage.

 

 

 

 

 

At this point I realised I had made a slight error in that the lower skin of the stub wing should have actually extended out and on to the lower surfaces of the fuselage formers as can just about be seen on the build guide images below. I don't think this will be too much of a problem though, time will tell I guess.

 

 

I glued a balsa block between the upper and lower wing spars for support and to blank off the end of the carbon tube. Also just noticeable in this photo is that I wasn't very happy with the strength of the smaller carbon tube so wrapped a layer of glass fibre matting around it.

 

 

I neatened the servo hatch opening by adding a border of 0.8mm ply after which I then added a further layer, this time in 1.5mm ply and set underflush with the wing surface by 0.8mm to accommodate my 0.8mm ply servo cover.

 

 

Four little webs in the corners for the self tappers to screw in to and it was done.

 

 

 

Inexplicably after all that I have somehow ended up with the servo and aileron horns being slightly out of alignment but not too much to be an issue thankfully. 😕

One day, should I ever get myself a 3D printer then it would be neater to have a cover with an integral fairing to hide the servo arm altogether.

 

I then installed the servo lead, gluing the MPX plug in place slightly overflush with the rib surface, as with the carbon tube, to allow for a finishing ply facing.

 

 

Once the glue had set I then poured hot-melt glue over the rear of the plug to make everything good and secure.

 

 

 

The next steps would be to add the upper sheeting, leading edge and wing tip and then go on to hinging the aileron but I think at this point I may try to make a matching right hand wing so it may be a little while before my next update. 🙂

[Saint 1]

Ta-Dah!

The right hand wing didn't take quite as long as expected 🙂

 

 

Before going any further I need to first apologise and make a correction to my previous post:-

I am covering the wings with 3/32" (2.4mm) balsa sheet, NOT 1/8" (3.2mm). 

 

Back to the build....

 

I've also now made the right hand stub wing but this time decided to leave sheeting it until after it was attached to the fuselage.

 

 

I glued both the stub wings to the fuselage using a combination of Super phatic for the wood-wood joints and epoxy for where the epoxy resin-filled areas butted against the fuselage former.

 

 

For the first time I was able to attach the wings and have something resembling a plane 🙂

 

 

 

For extra peace of mind I decided to add triangular fillets of balsa where the stub wings joined the fuselage and also both above and below where the spar box sections joined the fuselage former.

 

 

 

With that little milestone achieved I went on to fitting the elevator and rudder servos. As with the ailerons I wanted to be able to replace the servos should I ever need to so it took me a while to figure out quite how I was going to do that as well as position them appropriately to align with the rudder and elevator control horns. A multitude of small pieces of balsa later I now have something that looks like it may just work. I had to shorten the servo wires to keep things tidy but hopefully I should now be able to have a single screw on cover over both servos and their plugs.

 

 

 

I fitted the MPX plugs within the stub wings and was then able to connect everything up to a receiver and test out the connections.

 

 

 

I'll probably go back on to the wings again next and get the upper sheeting fitted...

 

Edited June 5, 2023 by Saint 1

[MikeQ]

Hi

 

Some very neat building there.

 

mike

[Phil Cooke]

Lovely work Phil, as Mike said, very neat work! Impressive for your first balsa bash!

[Saint 1]

23 hours ago, MikeQ said:

Hi

 

Some very neat building there.

 

mike

 

23 hours ago, Phil Cooke said:

Lovely work Phil, as Mike said, very neat work! Impressive for your first balsa bash!

 

Thank you both, I must say I'm finding building in balsa much more forgiving than Correx. Rather a lot of sawdust everywhere though...I've never done so much vacuuming! If I'm not too careful I might become domesticated 😁

[Andy Meade]

She's looking fantastic Phil, you're turning into one of those perfect balsa builders like Mr Cooke and John Hey!  

[Saint 1]

10 hours ago, Andy Meade said:

She's looking fantastic Phil, you're turning into one of those perfect balsa builders like Mr Cooke and John Hey!  

Thanks Andy, I think I still have a way to go on that front though, if only I was a perfect pilot like them too 😄

[Saint 1]

A bit more progress on the wings...

After gluing on and dressing back the upper sheeting I soon realised that the leading edge stock I had was not going to be much use.

 

 

The vertical depth of the leading edge tapers from the root to the wing tip so I needed to glue on a block of balsa with the same taper and then sand it to the required profile.

 

 

 

I made up a ply sandwich for the wing tip with a 1.5mm ply filling between two slices of 9mm balsa, roughly sanded it to shape and then bonded it in place, ensuring the ply aligned nicely with the aileron leading edge and especially the trailing edge.

 

 

 

Not immediately obvious in the above photo but I have also glued 0.8mm ply facings on either end of the aileron and the wing's mating faces.

 

After some more words of advice from Phil Cooke 👍 it was then time to radius the aileron leading edge. I used suitably sized sockets to draw a radius on each end of the aileron, then drew a line along the tangent point on the upper and lower surfaces, followed by a centre line. I then used these as a guide to sand the radius. The underside was a little more tricky since the control horn was in the way 

 

 

 

 

The hinge point of the Robart hinges needs to be at the centre of the radius so I cut slots at each position and drilled holes to accept each hinge.

 

 

I then used some carbon rod offcuts to make three little pointers to fit within the aileron holes such that when offered up to the wing they then marked where the mating holes needed to be drilled.

 

 

 

Finally, I had a working aileron...

 

 

and I finished off the wing by finish-sanding the wing tip.

 

 

 

 

After finishing off the other wing to the same point, next on my list will be to sheet the fuselage stub wings, after which I will be at the half-way stage 

The build guide then suggests I should continue with the remainder of the fuselage planking. 

 

 

 

Edited June 11, 2023 by Saint 1

[Saint 1]

I’ve managed to make some good progress this week so here’s the latest instalment...

First on the agenda was the fuselage stub wings and in particular adding the extra section of skin to the underside of the left hand stub wing.

 

With that little rectification out of the way I then went on to adding the remaining upper and lower skins.

 

 

I was then able to add the leading edge profile pieces and the ply facings. I had used 0.8mm ply for the facings on the wings but found it necessary to use 1.5mm ply here to ensure there was minimal gapping along the wing joint. (My positioning of the MPX plugs is what necessitated me using the 1.5mm ply).

 

With the profile of the ply roughly sanded back I could then fit the wings and finish sand everything together

 

 

There is a bit of gapping towards the trailing edge of the right hand wing which I may yet be able to improve a little but overall I’m pleased with the result.

 

 

So then it was back onto the fuselage planking. Generally I’ve been cutting tapered sections from typically 10-12mm down to around 2 or 3mm. This process worked well on the rear fuselage sides.

 

But on the fully circular forward section it started to result in the planks taking on a banana shape.

 

So I had to get creative and cut some curved pieces of planking to bring everything back to something like straight – a lesson learnt for another time.

 

 

 

From the build guide picture it looked like the planking is ultimately dressed flush with the canopy base so I decided to add a little extra support for the planking in that region using some scrap balsa pieces.

 

 

With that done I was then able to complete the fuselage planking.

 

 

 

And now I have a plane looking remarkably similar to page 12 of the build guide.

 

 

 

 

The fuselage planking and cockpit opening now all need to be sanded smooth before moving on.

The next few pages of the guide relate to creating the faired sections between the fuselage and stub wings...

 

 

But I have one or two things to think about here before I rush ahead with any of that, namely for one, the plan built model (as shown above) has no actual engine air intakes so for my build I would like to have something a little more scale looking in that regard. Secondly, the installation of a suitable wing retaining mechanism. Frankly the wings are such a good tight fit (no doubt helped by the MPX plugs) that I could probably get away without any form of additional retention but best to be sure I guess. 

[Saint 1]

There’s been quite a bit of sanding this week, starting with the cockpit opening and then prior to tackling the wing fairings I needed to sand most of the fuselage too, leaving just the tail section to do another time.

 

 

With the bulk of that done I went on to creating my wing retention mechanism, cobbled together from a pair of M5 wing retaining bolts and captive nuts, some old biro tubes and a length of aluminium tubing.

 

 

I turned the heads of the nylon bolts down so they slid inside the biro tubes easily, making them something like a very long grub screw. The plan was to drill a 5mm clearance hole through both the outer and inner carbon tubes allowing the nylon bolt to then be screwed through and thus retain the wing. Should the bolts ever shear off on landing then the heads should fall easily out of the tubes and any remaining threaded portion will drop inside the fuselage and with any luck I will then be able to jiggle it forward and out through the cockpit opening.

I was somewhat nervous about drilling the carbon tubes, fearful of the holes being off centre and weakening the tubes especially since as I was drilling them blind. After some careful measuring to determine where the drill centre needed to be I then decided to make a little jig to help minimise any drill wander.

 

 

I started with a small pilot hole to check the hole's position and then worked my way up to the 5mm clearance hole in 4 stages.

Because of the hole's location I used a pin vice to lengthen the drill's reach and had to cut a larger than ideal access hole through the stage 6 fuselage former too.

 

 

The biro tubes alone weren’t long enough to reach from the captive nut to the air intake, I had some thick walled aluminium tubing which whilst long enough was also quite heavy so I opted to combine the two, linking them together with the biro’s rubber sleeving.

I added the intake formers either side of the fuselage along with my additional bridge pieces of balsa to form my dummy air intakes. With those glued in place I was then able to glue in the tubes. (The drill bit within the tubes was to ensure the flexible rubber joint between the biro and ally tubes remained straight whilst the glue set).

 

 

I added the exhaust formers as per the plan and then made some leading edge pieces around the intake openings.

 

 

 

 

I had to then subsequently cut part of the intake former away to improve the appearance of the intake.

 

 

And then neatened everything up with a bit more sanding.

 

 

A bit of extra excitement this week…The canopy arrived from Gliderworks and very nice it is too! Much thicker and stronger than anything I could have produced from pop bottles and very well packaged.

https://gliderworks.online/index.php/product/seahawk-canopy-pre-order/

 

 

 

Time to sheet the faired sections…

The fuselage former spacing is generally around 4” but between stages 7 and 8 this extends to 5” so I decided to add some extra balsa support pieces.

 

 

 

Prior to sheeting I also then added supporting strips of scrap balsa sheet around the edges of the openings.

 

 

I gave much thought as to which way to run the grain direction on the faired sections and eventually opted to run it longitudinally for the most part but transversely around the more curved leading edge sections which I think may well be the build guides intent. A fair bit of measuring and trimming was entailed but the process wasn’t as difficult as I had first anticipated. I started on the upper surfaces...

 

 

I chose to do the leading edge in small segments primarily due to the curvature but it was also much easier to trim the smaller pieces to size.

 

 

 

It took a while but fitted reasonably well all round and with only a few areas that will require filling in due course.

I did the underside in a similar manner.

 

 

After that it was yet more sanding to round everything off and then time to refit the wings for another photo opportunity.

 

 

 

 

 

 

Out of curiosity I thought I would take this opportunity to weigh it and see where I’m at in relation to the 1.3kg AUW of the prototype build aircraft.

 

The prototype used 1.5mm (1/16) balsa covering everywhere whereas I’ve gone 50% thicker, using 2.4mm (3/32) on the wings and double the thickness by using 3mm (1/8) on the fuselage. In addition I’ve used ply formers in lieu of balsa in a number of places and I also of course have the additional weight incurred by having detachable wings and a rudder.

 

I loaded it up with a battery, receiver and all the servos and my new canopy and it currently stands at 1.75kg which I don’t think is too bad. Mine is still missing its nose, tail fin covering, rudder, tailplane and any detail items like the pilot and then the biggy which will be final covering in glass cloth. I’m not sure how much weight the cloth will add but hopefully I’ll be able to keep the finished weight below 2.5kg. I’m fairly certain I’ll be able to balance the model with little if any additional nose ballast. It certainly feels light for its size as it stands anyway so I’m hopeful.

 

So that was page 15 of the build guide completed. I’m going to skip page 16 for now, which is the nose block and move on to pages 17 and 18 – the tail fin covering, tail plane and rudder.

You may have noticed that whilst my Sea Hawk now has air intakes there are as yet no exhausts. That’ll be page 19. 

[Phil Cooke]

great update Phil, excellent - those wing fairings and your wing retention method both look the business!

[Saint 1]

1 hour ago, Phil Cooke said:

great update Phil, excellent - those wing fairings and your wing retention method both look the business!

Thanks Phil, credit goes to you of course for the wing retention suggestion 👍

[john stones 1 - Moderator]

Missed this one somehow, seriously good work Saint. 👍

[Mike Chantler]

Looks great, fantastic bit of building 🙂

[Saint 1]

22 hours ago, john stones 1 - Moderator said:

Missed this one somehow, seriously good work Saint. 👍

 

22 hours ago, Mike Chantler said:

Looks great, fantastic bit of building 🙂

Thank you both, it might be a while before my next update, one or two other things on the go just now plus I'll be back off to the Orme with the PSSA gang again this coming weekend.

Thanks again,

Phil

[Saint 1]

I’ve managed some more time on the build again so I thought it was about time for another update. This time I’m covering pages 17 and 18 of the build guide – sheeting the tail fin, constructing the tailplane, elevators and rudder. I was working on various bits at the same time but will endeavour to list them below in some kind of logical order!

 

Before sheeting the tailfin I had to build the internal frame thickness up in the central portion and then sand it to an aerofoil shape (allowing 1.6mm for the sheeting either side).

 

 

Holding the balsa sheet in place whilst the glue dried to quite a bit of tape and pins.

 

 

It was at this point I noticed what looks to be an anomaly within the plans. The fin and tailplane are designed to slot together and there is a 10mm slot in each for this purpose but the finished thickness of the fin and tailplane is in the region of 18mm – way too large to fit in the slots. I had yet to make the tailplane so could make a larger slot no problem but there wasn’t much material to play with on the fin.

 

 

I ended up gluing some block balsa above the slot (which also served to support one of the Robart hinges) and then glued a thinner strip below, still leaving some space for my servo wires. At this time I also glued in some small pieces of ply to provide something a little more solid for my servo cover screws to tap into (the pencil dots marking their locations).

 

 

I emailed the plan designer regarding the slots so maybe the plans will be revised at some point in the future.

 

With the slot opened up in size I was then able to sheet the other side of the fin – yet more pins!

 

 

 

As shown on the plans the tailplane looks to be of an open framework design to be covered with Solarfilm or the like.

 

 

But I wished to sheet mine in the same way as the wings so revised the plan accordingly, introducing the wider slot along the way.

 

 

I used a piece of basswood for the tailplanes trailing edge to give it a bit more strength and then balsa everywhere else. Whilst the tailplane is nominally flat the underside does rise up towards the tip more than the upperside comes down so it does end up with a small amount of dihedral as a result.

 

 

 

I sheeted it top and bottom with 1.6mm balsa

 

 

Sanded it back

 

 

Added the leading edge pieces and sanded those to shape

 

 

And then added the tips using the same ply sandwich method as for the wings and sanded those to shape too

 

 

The rudder construction went pretty much according to plan but I again included a ply sandwich to help give a neater and sharper trailing edge.

 

 

 

 

As with the fin the rudder needed to be sanded to shape allowing 1.6mm for the sheeting

 

 

 

Prior to sheeting I made and glued in place a fibreglass control horn.

 

 

 

I made a cardboard template for my servo cover

 

 

Once happy with that I then made one in 1.5mm ply, hopefully once fully finished it should be reasonably discreet.

 

 

The elevators are made in solid balsa and linked together with a tie bar. Again I wanted to make a fibreglass control horn but it took me quite some time to figure out a secure way of attaching it, eventually settling on two pieces of fibreglass slotted together and sandwiched within one of the balsa elevators.

 

 

 

 

After some considerable sanding I eventually had something resembling an elevator

 

 

With both sanded and the tie bar inserted it was starting to look like it might just work.

 

 

 

The next task was sanding the leading edges and fitting the hinges. Thank you to the chap who spoke to me about my Sea Hawk build on the Orme the other weekend (apologies I didn’t get your name) but this time I endeavoured to keep the slots accommodating the Robart hinges to a minimum. In my naivety when making the ailerons I cut the slots full depth right down to the hinge points meaning it is very nearly possible to have +/- 90 degrees movement, great for flaps but far more than necessary for ailerons.

 

 

With the tailplane and elevator assembly installed you can see that in time it will be necessary for some balsa infill pieces front and rear.

 

 

 

I sanded and hinged the rudder in much the same way and then assembled that too

 

 

Suitably pleased I thought it was time to add the wings again. 

 

 

 

 

I’m starting to feel like the end of the build stage will soon be in sight, just 4 more pages of the build guide left now (plus not forgetting the nose that I skipped on page 16). Items still to do are the ‘bullet’ which fits in front of the tailfin (no idea what function that performs), the exhausts (could be fiddly), canopy and cockpit. Then of course there will be the other detail stuff to think about like the arrester hook, no idea how I’m going to make that yet (unless anyone is able to 3d print one for me of course) but it will be attached by magnets.

 

Phil

[Saint 1]

Another little update on my Sea Hawk build.

 

Having realised I had made my aileron hinge cut-outs unnecessarily large I decided to revisit them and cut a series of small noggins of balsa to reduce their size.

 

 

Once glued in and sanded to shape they looked much improved – I couldn’t have done something like that on my Correx builds!

 

 

 

 

Next on my list was the ‘bullet’ piece that fits in front of the tail but prior to that I needed to glue in some little slithers of balsa where the tailplane leading edges met up with the fin.

 

 

As per the guide the bullet piece was made by turning the front section in balsa and then I also turned the rear section too and then cut that into quarters to fit around the fin and tailplane.

 

 

After much fiddly sanding I ended up with pieces of roughly the right shape, after which I then glued them all in place. (One day in the future I’m sure I’ll probably manage to knock the bullet off again whilst loading and unloading things from the car!)

 

 

 

 

 

The exhausts have taken me quite some time to think about and create. The guide suggests creating them with two 48mm discs of 15mm thick balsa, glued to the stage 10 fuselage former followed by creating various infill and fairing pieces to blend them both in.

 

 

I wanted to try and make them a little more realistic and found that deodorant aerosol cans bore a reasonable resemblance to the jet exhausts. After procuring a couple of empty ones of the right size I sanded the text off, cut them down and sprayed them with some clear sealer.

 

 

I then made the outer tubes by soaking some 0.8mm ply in hot water then rolling them around the same deodorant cans, taped up until dry.

 

 

I was then able to create the two outer tubes, gluing them around a disc of balsa at one end in the process. By rolling two thicknesses of the ply I was also able to make spacer rings to locate the jet exhausts centrally within the outer tubes

 

 

With some trepidation I cut into the sides of the fuselage, located precisely where stage 10 former was and then proceeded to cut away more of the balsa sheeting to the dimensions provided within the build guide.

 

 

Some additional Dremel action also removed pretty much all of the balsa exhaust former.

 

 

Once happy with the cut-outs I then glued the outer tubes in place, trying to position their longitudinal joints in the least conspicuous area in the process.

 

 

 

Then it was a case of very carefully cutting most of the outer tubes away again to create the desired shape.

 

 

 

Four near identical fairing pieces were then required. I cut and sanded some balsa sheet to match the cylindrical shape and then managed to very carefully cut the tapers on my scroll saw. A bit more sanding and trimming got them to a flush or slightly over-flush condition.

 

 

Before gluing the fairing pieces in place I wanted to improve the way the wings trailing edges blend with the fuselage, as built there is a sharp corner.

 

 

On the real aircraft there is a nice blend radius at this point so I cut some 3mm ply to suit and glued those in place, followed up by the four fairing pieces.

 

 

With the jet exhaust temporarily inserted it is now starting to look something like.

 

 

Much filling and sanding is going to be required before too long now I reckon