Topic: Spitfire Mk9 build

Cavem,
What are the dimensions of your airplane.  I could not fine the scale or wingspan and such.
I really will following your build.  I want a Spit maybe next year I will start.  What brand or name of designer please.
Take care,
Albert

Hi albert0147, gland you're interested. My first attempt at a scratch build. I downloaded the Dave Philpotts plans from here, Item 56: http://plans.am.free.fr/

I then had them printed by http://www.cadtoprint.co.uk/shop.php?action=index for just £12, 2 A0 and one A1 sheet.

This has a 49" wingspan and hopefully will weigh in at around 4lbs when completed. We'll see!!

Hello Chedder CM,
Well I kind a like my planes around 80".  What advantages and disadvantages as far as easy of flying would one expect large vs. smaller?  Please jump in you other guys.  Maybe to a lesser degree building between each size.
Albert

My main reason for this size is the size of my shed! I guess the main difference in size is speed, smaller equals faster?? Not sure!

Hello CM,
Yes shed size .  I am finishing my 82'' P-47.  First build.  Maybe next summer or Fall finish.  Very slow and now little time as am working again.
Thanks,
Albert

Larger = faster but more stable in the air normally. The weight of a large model will make it faster. The larger wingspan will make it less twitchy in the air. Larger models need more space to take off and land due to the weight normally.

Are there anymore pics on the build there Chedar?

Larger = faster but more stable in the air normally. The weight of a large model will make it faster. The larger wingspan will make it less twitchy in the air. Larger models need more space to take off and land due to the weight normally.

Not necessarily. I find larger models can fly more slowly, it is the wing loading which counts. An 80" Spitfire will fly much more slowly (and smoothly) than a 48" 'Funfighter' type. Try this: http://www.airfieldmodels.com/information_source/math_and_science_of_model_aircraft/formulas/wing_loading.htm

Bob

A quick update! Now on build three of the tailplane (heaven help me when I come to the wings) as there is no info at all on the plans as to what the various parts are made from - the leading edge for example? There is also the fact that it tapers, both top and bottom from the center to the tips.

DOH! (As Homer would say) just looked more closely at plan sheet 2 and all is explained It is built in two halves, top and bottom! The ribs are cut in half at their centre line (I wondered why this was marked on each rib!) and then one half is built on this flat split line, covered, and then repeated for the other half and then the top and bottom halves are joined together on the split line - easy

 Lesson:  MAKE SURE YOU THOROUGHLY STUDY THE PLANS BEFORE BUILD COMMENCES 

Build three starts today, cut another set of ribs etc etc.....

LESSON 2 - WHEN YOU REACH OVER THE BUILDING BOARD TO PICK UP SOMETHING ON THE OTHER SIDE, MIND THE TAIL FIN 

Don't you just love the emoticons that indicate just how you feel

OK, I think I got it right this time. Re cut all the formers, cut each in half and made two half tailplanes.........


Then it was just as case of joining them together.........


Once dry, a bit of sanding should have it sorted

Now thats interesting, as i am building BT hurricane. Looking at plan it shows in cross section a single 1/16th balsa core, as you show its built top and bottom(i think)and two halfes joined later. Now if i am wrong i will end up with a tail too thick because i use two 1/16th cores. To add to the plan confusion it appears to show a single Spar as tho its built as one core. I have attached my plan shot and it may bring back all the nightmares! Can you assist please

Hi Flatliner, I too am building the BT Hurricane and have used a single sheet of 1/16 at the core, built one side then flipped it over to build the other. Interestingly though my tailplane ended up being neraly an 1/8 to thin so maybe there is more to it than I read. But to me the plan clearly only shows on core sheet.   

Cheers
Danny

It took me three attempts before I realised that the tail and elevators are all built in two halves, top/bottom then joined at the split line. Today I finished sanding the tail and have just assembled both elevators. They just need sanding down. They were fiddly to say the least with the ribs no more than 1mm x 1mm in places! Well pleased with the result though

That tail is looking fantastic. I'm in the long process of building Brian Taylors Corsair. Most likely take years. When I built the tail it looked as if it was asking for one skin in between the two halves but I built it with the two skins and joined them. It has worked well because it alows the top sheet to over lap the elevators.

(Attachment Link) Now thats interesting, as i am building BT hurricane. Looking at plan it shows in cross section a single 1/16th balsa core, as you show its built top and bottom(i think)and two halfes joined later. Now if i am wrong i will end up with a tail too thick because i use two 1/16th cores. To add to the plan confusion it appears to show a single Spar as tho its built as one core. I have attached my plan shot and it may bring back all the nightmares! Can you assist please

That plan is the same as the Spit, a single "core" although in the Spit it is just a 0.4mm ply one. This allows one to build the first half on a flat board and once set remove from board and stick the other half ribs etc in place, well that's what I did with the elevators and they look right.

So come on chaps whats it to be single or double core  I find if i stand and look at the plan long enough on one leg I can see two cores I thought flipping a single core and adding ribs was going to be fiddly at best and probably end up banana shaped and two cores really won,t add much weight tho 1/16th thicker. This may be a descion for the pub

What if you built up the ribs, LE and TE then sheet the top on both halves then glue the centre skin to one half then glue the other half to that? This makes sense to me. This way you are not trying to build and layout the ribs on a plan that is being covered by the centre skin. Both halves turn out exactly the same and the final job joining the two is easier.

How does that sound?

When I built the BT Hurricane, I took the plan to mean one single 1/16" core, assemble the ribs on one side but don't shape to section. Then flip over and assemble the other sides ribs, then sand to section. It'll stay true without issues.

Hope this helps,

Ian.

When I built the BT Hurricane, I took the plan to mean one single 1/16" core, assemble the ribs on one side but don't shape to section. Then flip over and assemble the other sides ribs, then sand to section. It'll stay true without issues.

Hope this helps,

Ian.

Yep, that's the way I've gone. That way you build on a flat surface and, as you say, it stays flat as long as you're careful when you fix the ribs to the other side.

If you look at this picture, the "core" is actually just a very thin, 0.4mm ply former. (Thank goodness for super glue)!

Now I've just got to sand to profile and cover with 1mm balsa.

Thanks for all the input guys, think i have layed the issue to rest.Start tomorrow, single 1/16th core pinned flat, add ribs and spar plus TE then flip, add other side then sand to section and finally the sheeted sections. "Simples"

Right, that's the tail just about completed, just a little more sanding needed to reduce the thickness as I only had 1.5mm balsa not the 1mm called for. Also need to locate the hinges. Think I've got some somewhere
Next the rudder. Same build technique as the elevators etc., first half flat on the board, then remove from board, add other side ribs and then cover. Sorted

Lovely work 

If this is going to be a MkIX Spitfire you may want to look at modifying the elevator tip shapes 



Cheers
Danny

Umm interesting! I'm just following the plans and hadn't looked around for authenticity! Here's a real time picture that confirms the elevator/tail ends are a bit wrong! http://www.flickr.com/photos/jamesv9820/385385100/#/
Any way, being my first from-plan build I'll leave it as is for the time being.

Today I started on the rudder. Side one built on the board/plan......



and side two off the board.......



now for sheeting and sanding

Now you have opened a can of worms with that picture  ..... thats supposed to be a MkV but the elevators are from a IX or later. The wings are II - V

If you are not worried about authenticity then perhaps we should leave that rock unturned 

Its a really lovely looking plan though, and looks nice to build 

Cheers
Danny

Thanks Deptic. Quote from a Spitfire website:

"With the emergence of the Focke Wulf 190 aircraft in the skies over Europe the need for upgrading the Spitfire became especially apparent. To quickly regain parity with the FW190, engineers took a Spitfire MKV aircraft and fitted the new 1,565 hp Merlin 61 engine, producing the MKIX Spitfire. This power upgrade was extremely well received by RAF pilots, the MKIX gave them the machinery to match the FW190 and out perform virtually anything else put up against it at the time."[/i

So the Mk9 was in fact jut a modified MkV which explains the similarities. The single biggest mod was the advent of the new RR V12 Merlin 61 engine

Bit more fiddling around today. For some reason decided to make the two ply laminate retracts mountings and then, having centralised and clamped the fuselage onto the jig centre line I added three planks on both sides and the top rear to lock in the shape. Having removed the clamps it sits there nicely so no twist there
Fuselage looking from the rear. The rudder is only hanging there, not fixed!


and looking from the front

MkIX's had both the straight- and kinked-hinge-line elevator shape, and some had the later rudder shape as well. There were lots of variations on the production lines, and aircraft sent back to depots for Cat 3 or 4 repairs would often be fitted with major components from earlier "donor" airframes. So there were MkIXs fitted with tailplanes, rudders or ailerons from MkIIs. Similarly some might even get the earlier windscreens (with the external armoured glass panel rather than the flush one) if there was a shortage. There were also about six different wing configurations fitted to MkIXs and at least three different weapon layouts (two cannon, two dummy stubs and four 303mgs, the same without the dummy stubs, and a two-cannon, two 0.5"mg configuration) with a variety of upper surface fairing layouts. The later MkIXs had wider wheels that needed bulged undercarriage doors, and there were three (at least) different air intake layouts and two different radiator configurations. Some of these differences were developmental improvements and some were simply due to parts shortages.

Abysmal fleet configuration management, but I suppose there WAS a war on...



PDR

Looking great! Do you think it will fly well with that board attached to the bottom like that?
I always thought the spitfire could use and under slung board.

  but as I said, I probably wont be flying it, I just like the build so that will make sure it stays firmly on the ground

Just a thought on this build as I get near to starting the wings. On the smaller items I have only used CA (superglue) but is this suitable for the wings? Is it strong enough by itself or should I back up with a good PVA?

Oh and another thing, how does one stop glasses steaming up when wearing a dust mask? Most annoying as I need reading glasses on when doing fine sanding but they immediately steam up as I breath out

Use wood glue or Aliphatic for sure. A[[ly some sponge strips to the bottom of your glasses. Stops the moisture/ heat traveling up into your glasses.

Build continuing if somewhat slowly! Started on the wings, centre section Ribs 1 & 2 in and true. The oblong slots will accommodate the retracts mounting blocks.

 

Following my other thread, Washout Jig, http://www.rcmf.co.uk/4um/index.php/topic,87836.0.html I have done a "dry" assembly of the right wing with the jig under the bottom, rear spar. Look OK to you guys?



You can see the "white balsa" jig under the spar. If this looks ok it's in with the glue. Oh, also note the 84* angle on the first former to set the dihedral when attached to the root section.

Bitten the bullet and left and right wing frameworks glued and setting! Top spars to go on once the bottom ones have set and then a bit of sanding and planking

 

I to have issues with washout    I have been building for 20 odd years and NEVER built a wing needing washout I'm quite ashamed 

Looking good 

Question - does the plan specify shear webs between the spars?
If yes and they are exactly between the spars so as to form an 'I' beam, I've found it easier to make them before adding the top spar. If they are behind or in front of the spars to form a 'C' beam, they are better added after the top spar is in place.

Oh, and if the plan does not show webs, go back to the previous paragraph and make either...at least for the several rib bays from the root outwards...you will not regret it .

No the plan does not show any shear webs. In fact the plan also calls for hard balsa spars and I've upped them to spruce for a bit of extra strength. So some balsa webs would be a good idea as well? From other "kits" I've built these are usually balsa with vertical grain I think? Won't add a lot of weight so just might do it!

Shear webs greatly increase the strength of the wing. They don't need to be very beefy to have a big effect on the stiffness of the spar as a whole, so I'd add some from 1/32" or 1/16" medium balsa if it were mine - vertical grain.