62.5 Inch Tony Nijhuis Spitfire Build Log.

[GrahamC]

Well I picked up a CNC kit and wood pack from the RCME stand at the nats for a bargain price.

 

Having hunted around the internet I couldn't find a buildlog as such. It seems that there was once one on another site, but that seems to have long gone. So... Maybe its worth beginning one!

 

The Spitfire won't be my first build. I built a few free flight kits when I was (much) younger, and since I've been flying RC I've built and designed a fair bit in foam and Depron, and built a SLEC Funfly.

 

So I'me taking it steady, hoping to do a nice job and planning to learn some skills along the way. Current thinking is that this build will be electric, but a flying buddy keeps telling me that a warbird has to make some noise... So watch this space on that one.

 

I'm planning to glass it, or perhaps use WBPU and glass cloth. I've not used fibreglass before but am keen to learn.

 

I'm wondering about a redesign of the horizontal stabiliser and rudder to use a built up structure. I know that I have to keep the back end light. I have a copy of the 72 inch plan and am wondering about reducing that to suit. I'm aware from what I've read that there are others who have gone for a built up tail, and would love to hear more details.

 

Retracts are cheap and cheerful Hobby King units that arrived to day. Retractsis also new to me, but they look fantastic for the money!

 

Anyway on to the build so far...

 

Fuselage side components joint with aliphatic resin. I'm not a fan of superglue for building. I like time to fiddle!

 

I've picked up that there is a mistake in the plan. The RH side is the shorter. Not the LH side as indicated in the plan.

 

 

 

[GrahamC]

More to come... Just checking that my photos would work.

 

 

Cutting the 18mm triangular stock to run along the fuselage bottom. The wing seat doublers need to be trimmed to fit around the stock.

 

The same triangular stock needs to be fitted along the top of the fuselage in front of the cockpit . I used the kitchen steamer to make it a little easier to take up the slight curve that it needs to follow.

 

Having glued the triangular stock and wing seat doublers in place, the forward doubler needs to be fitted. Both needed slight trimming in order to but up to the rear of the fire wall and to the front face of F2. I reckon it will be a while before I need to buy solder!

 

I'm wondering about opening up the holes in the rear fuselage formers somewhat in order to begin my rear end weight saving campaign!

 

All comments and advice gladly accepted!

[Danny Fenton]

Hi Graham, I have a build thread on here for the larger 72" version. Many of the stages are similar, just scaled up, I am led to believe. I think a built up tailplane is an excellent idea.

 

Look forward to seeing more of your build

 

Cheers

Danny

[GrahamC]

Hi Danny - yes I read through your excellent build log - I'm very taken with the peel ply technique - and am planing to have a go on the wing - I even watched your lo-o-o-o-ng demonstration on youtube (Which is why I will try it on the wings first! - some of the tighter curves looked like a challenge - and at 62.5 inches the curves will be tighter.

 

Have you by any chance come across glass tissue? I was looking at fibreglass supplyers and was wondering if it might be more resiliant than solarfilm but lighter than proper glass cloth? Glassing is some way off at present, but its good to be planning ahead - and I'm new to that whole area.

 

I've been taking cardboard templates asI go of the bits. Handy if we have a prang, and I have been wondering about helpng my lad buld one mainly from depron. We will see! (He fancies the Focke-Wulf FW 190 in the special so we may go that way!)

 

Anyway on with the build...

 

The 18mm triangle stock needs to be thinned down at the tail so that the two sides can be drawn in together. It seems easier to do that before the two sides are connected so here is one side marked up. (I think I am being very clever deviating from the order of Tony N's instructions - so here is hoping that pride doesn't go before a fall in this case!)

Material removed with the David Plane. Wonderful tool when you have it set up right!

F1, F2 and F3 are all the same width, which means that they need to go in a right angles to the fuselage sides. So its over to that wonderful jigging tool called LEGO! (I hear it can also be used as a children's toy!) It's great having very accurate angles. Also ideal for wing ribs.

 

Here are the three formers in and drying...

As you can see all jigged square with LEGO, SLEC clamps and held down with a box of allen keys!

 

Working with PVA type glues (aliphatic resin) is slower, but I tend to build in twenty minute slots anyway so its not too much of a problem!

 

All for now

 

[GrahamC]

Ohh yes while I remember...

 

Problem: F2 seems to sit a little high in the fuselage as supplied. It was clear that the angle 'haunches' of f2 were going to interfere with the triangle stock rather than but up to them.

 

I seem to remember reading something about this on a forum, though it may have been the 72" version

 

Fix: F2 needs drop down in the airframe about 1.5 - 2mm. I trimmed it to fit over the wing doubler a little lower and trimmed the bottom of the piece accordingly. This is probably something that could be fixed later in the build when drawing the fuselage tops in, but it might prove fiddly. If I have trimmed too much away foaming polyeurethane glue will fill the gap!

 

I thought I would begin to compile an 'adendum' list for any other potential builder of things to look out for.

 

1. The Right hand side of the fuselage is the shorter NOT the Left as marked on the plan

2. F2 may need trimming to prevent it sitting too high in the fuselage and interfering with the triangle stock.

[GrahamC]

DOH! - First mistake made! Got back from donig one or two things planning to fit the other side of the fuselage only to realise that F1 doesn't go in at a right angle at all. The right hand side is slightly shorter in order to buld in a little side thrust. Anyway fortunately I managed to ease the firewall into the correct position.

 

Anyway F2 and F3 are in with the fuselage sides clamped together at the back.

 

 

This is the time when I wish I had splashed out on the SLEC fuselage jig at the nationals. Lets hope I can get the fuselage straight!

[Shane Sunday]

See this is why I love this forum so much. LEGO! I mean it's a building block. Great Idea and I have lego.

 

Oh by the way.

 

Subscribed.

[GrahamC]

Welcome Shane! One of the things I love about this hobby is the problem solving!

 

Well a few more bits and pieces on the build

 

Here are the fuselage tops going on.

I probably made a mistake here. It looks from the plan like I should have fitted the tail first and fitted the fuselage top pieces around it. I was thinking about a built up tail in an attempt to be a little more scale, but after sitting and scratching my head over the 71 inch version (Diferent shape tail) and a three view, I am wondering about just using the origional design.

 

Anyway, it shouldn't be too disasterous, I should be able to fill in to match.

 

I'm currently planning a removeable cowl. I have a few ideas about ways to achieve this, but will cross that bridge when I get to it.

 

Here the top is marked to give me an idea of the area to be razor planed away.

That done, I've set the fuselage aside. I need to find a suitable engine and mount. I'm currently planning on the ASP61 as used by Tony Nijhuis in the prototype or maybe a 70. I have my eyes on a few possibilities at the moment.

 

I also want to get the snakes into the fuselage. I feel a SLEC order coming on!

 

Meanwhile I've just started the wings...

 

So... I traced the plan onto grease-proof paper. It only takes 10 minutes, and it saves the plan from ending up full of holes, and can simply be flipped over when its time to build the second wing.

Plan in position with scrap paper beneath (helps me see the lines!) The plan is held in place with scraps of card staple gunned to the building board. Seems to work well.

 

I've cut the spars and dry assembled everything....

Which was a smart move, as I realised that I will need to trim W3 in order to make space for the drive unit of the electric retract.

I'll make a cardboard template to fit around the retract, and trim the rib accordingly. I will hopefully be able to get on with this a little tomorrow as its my day off.

 

On the other hand it might be flying weather! Forcast is a little windy, but I do have a Wot 4 so....

The oleos were from Gliders in Newark. I was able to pop in last week on the way to a conference. Very helpful and fantastic service. The retracts were from Hobby King and seem well put together.

A couple of questions for anyone watching:

1] Any tips for making sure I get the wings straight? I was planning to pin all the bottom spars down to my building board. Should that be OK? I know Tony Nijhuis suggests no washout, and I am planning on flaps.

 

2] Wheels? Any ideas where I can get 3 1/4 inch 83mm wheels that are not too fat? Less than 25mm would be great.

 

[Shane Sunday]

Try pinning through the spar. It's nigh on impossible. Alex says masking tape but your plan needs to be well secured. Check out giantcod for those wheels. They have almost everything and at reasonable prices too. Delivery time is super fast as well. I'll be keeping an eye to see how those retracts hold up. If they work well I may pick a set up for myself. keep her going as she's looking good.

[GrahamC]

I'm a fan of Giant Cod - but they only have 75mm wheels. Only out by 10% and very cheap, so I might go for them until I can find something better.

 

I didn't make the challenge of the wing clear. My concern was getting the geometry of the wing right. Being an eliptical wing its a bit tricky working out the position of the trailing edge relative to the building board. I think if I get this one wrong I might end up with washin - not waht you want on a war bird! Anyway after much head scratching, I think things should work out OK. Some picture in a moment...

 

But first - just found the photos of pulling the fuselage sides together....

 

Tail block clamped in position

 

The fuselage sides came in nicely. I jut damped the outside a little, and it turned out to be far easier than I anticipated.

A little gentle pressure from a clamp, and the front section comes in nicely too.

 

The blue pen marks the area that needs to be removed with the razor plane in order to make the top front fuselage flat enough for the top decking

 

Back with the wings in a moment.... (Not sure what the limit is on the length of the post)

 

[GrahamC]

Right on with the wings.

 

These have give me cause for a lot of head scratching! I've built a straight wing before. Nice and easy because, unless there is washout built in the trailing edges should all be the same distance above the building board.

 

I've also built a tapered wing, which is a bit more difficult, but then again, washout escepted, the trainling edges should all at least be in a straight line.

 

But a Spitfire has an eliptical wing. So....

 

I nearly made the mistake of pinning down the rear spars and the aileron fronspar to the board. I reckon the result would have been that I would have ended up with washin (as opposed to washout) as the trailing edge pulled the leading edge up.

 

Part of the problem is that most surfaces that accept pins have a little "give" in them even if they are mounted on a solid substrate. I'm using 6mm fibreboard underlay on a good piece of chipboard, but I'm beginning to see that plasterboard might be a good solution as it would have hardly any give at all.

 

I belong to a club and a mamber came up with two great ideas, but both depended on being able to accurately and consistently mark a centre line on each rib, and I couldn't see how to do that, especially on the ribs which are cut for the aileron.

 

I think that as an aspiring designer one of the lesons I've learned is that putting tabs on the ribs to be removed during the build takes a few minutes on cad, and saves a few hours at the building board!

 

Anyway a few more pictures of progress.

 

W3 with space for the electric retracts drive unit. Its quite a big hole isn't it? I may beef this up a little before I commence covering the wing.

A dry run. It should all fit together now! It would have been fiddly sorting that out after the wing had been built!

 

Well tonight, after a dry run, I finally decided that I had to go for it with the glue! The main spars were glued and weighted in position while they dried, and the Lego made its second appearance in the build for jigging ribs.

 

(I have a few SLEC rig jigs, but to be honest Lego works better. I may have to go hunting around the house for a little more!)

 

The floating trailing edges make me nervous....

So as the glue is still drying, I have decided to chock up the trailing edges.

 

But I'm still not 100% happy about it so...

I carefully measured the height of each rib above the board, and marked it on the plan. I hope this means that I should be able to build a matched set of wings when I turn the plan over to build the other side. The figures that I've come up with look about right too, so that has set my mind at rest a little.

 

Next job is to try and work out how to get the wing trailing edge / aileron leading edge correctly positioned, and correctly identify the aileron riblets, which are pretty close together in size!

 

If anyone does read my ramblings, I wouldn't want them to think that I'm not enjoying the build! I'm just cataloging my reflections as I go, in the hope that they might inspire and help other potential builders.

 

 

 

[Andy Blackburn]

I've just started the Spitfire build and am doing the wings first, I've come across the same "floating trailing edge" problem - I don't think I can build two straight wings that way.

 

What I've done is to make a couple of packing strips that sit just in front of the aileron spar and the 6x3 obechi rear spars to keep the ribs aligned (with a bit of washout added). Am planning to add the bottom wing skin first, followed by the top skin whilst the wing structure rests on the packing strips to make sure the wings stays straight.

 

P.S.

Like your use of Lego...

Edited By Andy Blackburn on 08/10/2011 10:48:26

[GrahamC]

Hi Andy, I'd love to see some pictures!

 

I've just finished the spar webbing and think that the box formed by the front and rear spar actually all looks pretty stiff.

 

This is my fist eliptical build, and also my first with retracts, but it seems that the downside of sheeting the bottom of the wing first is the great big hole for the wheel well . I' wondering if I sheet the top first if I can make some kind of cradle for the wing out of off cuts of foam to hold it in its correct shape while I sheet the bottom. I have even wondered about sheeting the top, laying a sheet of greaseproof paper over it, and then using a cheap can of spray foam, and a piece of scrap melamine board to male a cradle to hold the wing while I sheet the bottom.

 

Anyway, here are a few fairly boring picture of the spar webbing and leading edge going in.

Spar webs in and drying

Leading edge going in. The outer section is not yet glued. I will dampen it and ease it in so as not to pull the spar out of shape.

I put triangular bracing pieces on the aileron section of the trailing edge. I was concerned about the strength of the joins between the ribs and the trailing edge.

 

 

 

[GrahamC]

On with the wing.

 

There seems to be two schools of thought about sheeting wings. Some glue the sheets together first and then sand them smooth. Others fearing warps seem to prefer to cover wings one sheet at a time.

 

Well for pragmatic reasons, I went for the one sheet at a time approach. I simply don't have a spare work space big enough and flat enough to make a wing skin!

 

Here is the first sheet going on.

 

 

The top sheeted. I use contact adhesive on the structure and aliphatic resin between sheets. I also taped the joins to ensure a nice flat join. Seems to have worked well.

 

WIng does seem to have stayed nice and flat. I only dampened the sheet nearest the leading edge where there was more of a curve. One gap is not quite as neat as I would like, but filler should sort that out.

 

Another post a little later...

Edited By Graham Culver on 10/10/2011 19:00:08

[GrahamC]

When the top sheet was dry I lifted the wing, just to check that the retracts were going to be OK. They are not fixed in place, and there are no grub screws installed yet, but looks like they should work well.

 

The leg turns at the end of the video becasue it it catching a little on the rib.

 

Any way I sat the wing back on the plan with the trialing edge packing. I covered it with greaseproof paper, squirted it with cheap expanding foam, and plopped a piece of insulation board on top. I'm hoping that when the foam sets I will have a cradle that will help me to complete all the work on bottom of the wing without it warping. Foam is setting as I type and I'm hoping that my plans will work (and that grease proof paper id foam proof!)

 

My 'cradle' setting with a little weight. Can't wait to see it it works!

 

 

[Delta Whiskey]

Just picked up this fully built up model, chap says it's 63" wingspan and it's pretty scale except for the enlarged tail section, I can do proper measurement if it helps on any area? Enjoying your thread!

 

[GrahamC]

HI Delta Whiskey. Yes I've been following your own thread and worrying about what engine I should put in mine. Seeing as TN built the prototype around a 61 ASP four stroke, the comments about 90's have had me wondering! Fortunately I havn't taken the plunge and bought an engine yet. When I bought the cnc kit from the RCME tent it was suggested to me that I might want a little more power than the design engine. I must read get up to date with the posts on your thread and see what consensus has been reached.

 

Any way no building as such today. I've had a busy day. Did the foam cradle work? Yes. not as good as I had hoped, but better than trying to work on the wing on a flat surface. To be honest I may have been a little to keen and perhaps had I left the foam curing overnight it would have been a little better. Its pretty good, but not perfect.

 

Here is the wing sat in its cradle. I may get the other wing to this condition (while its all fresh in my memory) before completing the ailerons, wheel wells and skinning.

 

Wheels arrived today together with the wrong servos from Giant Cod. Its the first time I've had a problem with them. I ordered nice metal gear ball raced 14g servos for the ailerons together with servo plates and received little 9g cheapy servos. Anyway, I have opened a case with them, and they promise to answer within 24 hours. I really hope they sort it out quick because I'm such a fan!

 

Anyway the wheels were the closest to the right size that Giant Cod had. 75mm as opposed to 83. At about 60p each I thought I would get them and make space for 83mm ones in the wells in the hope that I find some somewhere. (Hobby King have some but I will wait untill I need a few more things from them)

Looks like they should work. May need to get the Dremmel out, but its all looking hopeful.

 

[GrahamC]

Just built some of the other wing. The second one goes together much quicker!

Lego doing its job again!

 

The heigts and packing points for the LH wing were all marked on my tracing of the plan> Now I've turned it over to build the RH wing I'm hoping that it should help me to get a matching pair! I need to make sure I can tell the difference betwen and 6 and a 9 when I'm reading back to front!

[Firstflight]

Thanks for your inspiring build thread, Graham!

I recently bought the plan and cowl to this lovely Spitfire from Tony and I'm planning to build it during the winter. As soon as I have finished my Arrow (designed by John Rutter) the balsa bashing will start.

I’ve will be follow your thread with great interest.

/Mattias

[GrahamC]

Well the other wing is nearly ready for its top skin. It just needs some trimming on the leading edge with the razor plane.

It doesn't look like flying weather tomorrow here, so I'm hoping to get some building done.

I shouldn’t complain! What a great day we had on Saturday. Warm and sunny up at the strip with just a light breeze, and my son passed his BMFA A test - so a good day!

Anyway, here is the frame of the wing nearly ready. The height of the trailing edges of the ribs above the plan has come out very close to each corresponding rib on the other wing, so I’m fairly happy so far.

[GrahamC]

Well I now have both wings sheeted on top, and the aileron structure in place. I've begun to tidy up the structure on the bottom of each wing.

 

Framework pinned ready for top sheeting.

Obviously you can't leave the structure pinned down because once the sheeting is on you can't get the pin out! My solution is to hold everything in place on the plan like this so as to try and keep everything the right shape, and when you are done the wing and sheeting should just lift off.

 

I use contact adhesive for the sheeting. As I explained before, I simply don't have a big enough space to glue all the sheets together first, so pragmatic reasons dictated that I go for the one sheet at a time method.

I built a SLEC Funfly, and the instructions for that suggested this method. I run a bead of adhesive along all of the structure covered by the sheet. Press it into place and then lift it. I make sure that there is sufficient adhesive along each line.

I don't leave it to completely dry before afixing the sheet. If it is slightly tacky you get a little leeway. If it is really dry you only get one go at getting it right, and I'm not that good! I find that the sheet presses into place really well. There is no need to weight down the sheets.

What is it about building? You simply have to see what bits look like together! I'm just checking here that it looks like the root ribs will go together. Everything looks good so far.

TIme to put in the aileron leading edge. I cut throught the sheting along the trailing edge in a few places so that I will be able to cut it accurately when the time comes. The aileron leading edge is from 9mm sheet. I cut it roughly to shape, and then ran a pencil along as shown to get a rough idea as to the shape of the top of the piece. A few minutes first with a razor plane, and then with a permagrit block and...

Then sticky tape is placed on the trailing edge to prevent any stray glue joining the pieces together, and...

Glued the aileron structure in place. It is very difficult indeed to tell which aileron rib is which, and I think I got it wrong! (On this wing anyway) Hopefully, it's not too much of a disaster, but I reckon that the rib marked in the following (dreadful) photograph is a little too short.

More to come...

 

 

 

 

[GrahamC]

Posting was too long!

 

Anyway, I've marked it, and will pack it up a little with some scrap wood, or maybe just use a little polyurethane glue when it comes to covering the aileron.

Talking of polyurethane, I was a little nervous about some of the joints and decided to beef up the aileron by applying small fillets of the glue. It weighs very little but produces good strong fillets. (In case you are wondering, its what is sold as Gorilla Glue, but I use a brand called Joiners Mate which is available from Screwfix.)

 

Finally, I have trimmed up the bottom of the leading edge of one of the wings.

 

[Andy Blackburn]

> Hi Andy, I'd love to see some pictures!

 

Better late than never, I suppose. You must spend every waking hour at the building board!

 

This is the basic wing structure (webbing not yet added, but retract bearers and retracts checked for fit) that has been assembled without any packing pieces of any kind using odourless cyano and Superphatic. Amazingly, it's nearly straight, apart from a small amount of washin on the last couple of rib bays:

 

...and here are the packing pieces made from 1/8" balsa; I'm using 6.3mm (1/4") at W1, 10 mm at W6 and 7mm at W11 which should give about 1 degree washout at W6 and about 2.5 degrees washout at W11.

 

Dunno yet if it's going to work as advertised (can't try it until the false LE is shaped because it gets in the way), thought it was possibly worth sharing though.

 

[GrahamC]

Hi Andy - looking very familiar which must be good!Thanks for posting the photos.

 

I've been going a month on my build, so it's not that quick! I'm not a fan of the TV and tend to grab 20 minutes here and 20 minutes there. That might be more of a problem as as the shed gets colder and colder!

 

I've never really built with cyano so after 20 minutes I normally need to leave things to dry!.

 

Anyway I've done a few more bits on one of my wings.

 

I should say that I mentioned a problem with Giant Cod delivering the wrong servos earlier in the thread, and they have now sorted that out.

 

Anyway I had to order some bits from them for another club member and ordered this chap at the same time.

 

He is sold by GC as 1/6 but he is nearer 1/7. Not bad for less than £4. I think he needs a name!

 

I also got these servo holders for the wings from Giant Cod. This is just an old servo at the moment to check the fit. It's a shame that I had to notch the servo bearers to fit the holder. I've actually subsequently added a web of ply to the back of each bearer to make up for some of the material removed.

This should all look nice and tidy once the bottom sheeting is in place.

 

Next job... Sorting out the retracts....!

 

BTW does anyone know is screwing them to the bearers will be adequate? Or do I need to come up with a way of fitting a captive bolt behind each bearer?

 

 

[Edward smith 2]

Hi, this looks great! I am trying to build a paper model of a spitfire, and want the wings as realistic as possible, can anyone share images of the wing cross-sections or rib shapes? It would be a wonderful help.