Yellow Aircraft 1/5 Spitfire XIV rebuild/repair

[Jon H]

Been a very long time since i worked on the Spitfire but my week off work has allowed some progress. 

 

Minor stuff really, as i decided to finish the rub down of the wing in the sun while i was doing the ugly mustang. I started this last autumn but it was too flippin cold. This time i had the opposite problem, but regular overspray splashes from the hose kept me cool while the wet n dry did its work. No photos, my phone overheated and died when i left it in the sun. oops

 

I also had a go at dealing with a crack in the fuselage. Its previous owner suffered many engine failures with it and so it had a few arrivals in its time. One of them split the fuselage along its top seam and put stress fractures in the sides. I cleaned and prepped the area before applying a thin layer of new glass over the top in a small section to make it look like a scale panel. I squeezed the fuselage to allow the seam to open up and get some resin in there before putting the sealing layer over the top. It seems to have worked out fine. 

 

 

More cracks need repairs but this was the first one to go. 

[Paul De Tourtoulon]

That's a fiddly job Jon, I had the same with the tail of my Esm Stuka, a real headache.

 

 so what colour is it going to be ?.

[Jon H]

not 100% sure but i keep coming back to this..

 

[Dale Bradly]

Do it! I've done a foamy in that scheme and it looks great in flight 

[Artto Ilmanen]

Hi Jon,

 

Have you yet flown this model? Curious to know as a friend of mine offered one for me at a reasonable price so I’m thinking..

 

 

[Jon H]

I flew it years ago for the previous owner but the rebuild is still in progress so its not flown since. My focus has shifted to the Top flite Spit i am working on and once it is at the same stage as this one i plan to paint both at the same time while i have all the spray equipment out. 

 

The Mk XIV is not my favourite Spit, i tend to prefer the merlin versions, but this flew so well before and with a really nice paint job in hand i couldnt say no, especially at the price. Also the friend that sold it to me offered it to me first as he didnt want to sell it on ebay to some clown who would smash it up as he has a sentimental attachment to it. To him, a big Spitfire was the whole point of the hobby. Everything he did was with 'big Spitfire' as the ultimate goal. 

 

Anyway, they fly extremely well, like all big Spitfires, so if one is available its definitely worth picking up as they we discontinued probably 15 years ago and you wont get a new one. If you ever see a Pica Spitfire kit available buy it and send it to me. They fly very well too and i regret selling mine. I only got shot of it as the saito 180 i fitted was pretty wimpy and i didnt have a bigger engine at the time. Had i waited a year i could have slapped a Laser in it but such is life. There was a new kit on ebay a while back which i ignored as i expected it to go for silly money. Sold for about £150. i was not amused. 

 

 

[Artto Ilmanen]

Thanks Jon,

 

I actually posted a question on suitable engine for this model at Laser Technical questions forum - as I didn't want to hijack(?) this thread.

 

I tried to compare pictures of this (yellow aircraft)  to real Spitfire MKXIV: not being an expert they look much the same but what's your opinion ? What is your opinion, how  true scale is this model? 

 

 

p.s. I read your thread "modifying the top Flite Spitfire I accidentally bought on ebay. I'm sorry to hear your loss. My sincere condolences to you and your family..I went through the same few years ago so I know how it feels. 

 

 

[Jon H]

The model is not super scale as its got a flat trailing edge to centre section, and things like aileron and flap placement are not exactly correct. Mine also had slightly funny shaped wing tips which i improved a bit when i repaired them. 

 

But, its no moose and most would not be able to tell you what was wrong with it from a scale point of view. In the air it certainly looks the part and i would not be concerned. 

 

For power, it originally flew on a hateful os BGX1 2 stroke. 35cc, unreliable. Power was ok though and it flew fine. Loads of them flew with Moki 180 and 210 engines and zenoah 38 and 45 were popular as well. I did toy with the idea of using a 240v, as it would fit really nicely in the cowl, but a MkXIV Spitfire should be a monster in vertical performance so i went for the 300v instead. I dont need the straight line speed, i just want the vertical performance. 

 

The only snag with the 300 is i need to get a little creative with my exhaust to minimise cutting of the cowl but i think its worth it. All that said a 240v would fly it fine, especially if its a lighter one with minimal detail. 

[Artto Ilmanen]

37 minutes ago, Jon - Laser Engines said:

The model is not super scale as its got a flat trailing edge to centre section, and things like aileron and flap placement are not exactly correct. Mine also had slightly funny shaped wing tips which i improved a bit when i repaired them. 

 

But, its no moose and most would not be able to tell you what was wrong with it from a scale point of view. In the air it certainly looks the part and i would not be concerned. 

 

For power, it originally flew on a hateful os BGX1 2 stroke. 35cc, unreliable. Power was ok though and it flew fine. Loads of them flew with Moki 180 and 210 engines and zenoah 38 and 45 were popular as well. I did toy with the idea of using a 240v, as it would fit really nicely in the cowl, but a MkXIV Spitfire should be a monster in vertical performance so i went for the 300v instead. I dont need the straight line speed, i just want the vertical performance. 

 

The only snag with the 300 is i need to get a little creative with my exhaust to minimise cutting of the cowl but i think its worth it. All that said a 240v would fly it fine, especially if its a lighter one with minimal detail. 

Thanks Jon,

 

It must definitely not be anemic in vertical performance - hence my question. Maybe I need to weigh the model to get an idea in terms of how much power is needed. I came across another thread in RCU were people reported huge variation in weight from 22 lbs to 30+lbs(?!). So let's hope this one is a light one.

 

Most say the model requires ton of lead on the nose: if so what about the reduction gear idea in conjunction with 240V ? If weight on the nose is not an issue could a reduction gear with 240V help with the performance? Bigger prop and good thrust yet enabling the engine operate at power peak at 9000+rpm?

 

If this could work I could be interested in investing on the reduction gear box.. or, I could of course sell the 240V and buy a 300V instead.

 

[Jon H]

30lbs?? What did they do to it? 

 

This one was 20/21lbs when it flew in its former life and carried no ballast at all. It will probably end up heavier by the time i am done as i intend to add more of a cockpit and pilot than it had before and this weight will be aft of the c/g. That said, i have removed the excessively heavy 1/4 inch ply servo trays and i will relocate the radio further forward than it was as the tank will be low to suit the laser and the normal tank bay will be open for radio and batteries. so it might all work out even, not sure at the moment. 

 

In any case though, i cant see it being much different to the way it was before and am aiming for 22 or less. 

 

One thing on the ballast. There is often great hysteria about models needing loads of nose weight or cries of incorrect cg on plans when in reality they just need to use lower elevator rates. If you balance the model further back you can get away with much lower elevator rates to retain the same level of sensitivity on the stick. A more aft c/g is very helpful as it makes it much easier to handle on the ground and will reduce the tendency to nose over. It also means the model is lighter overall due to the ballast left out. 

 

Warbirds do not need 45 degrees of elevator deflection. As i have said many times, my Sea Fury will loop on about 3mm of elevator so you really dont need much. 

 

 

[Artto Ilmanen]

10 hours ago, Jon - Laser Engines said:

30lbs?? What did they do to it? 

 

This one was 20/21lbs when it flew in its former life and carried no ballast at all. It will probably end up heavier by the time i am done as i intend to add more of a cockpit and pilot than it had before and this weight will be aft of the c/g. That said, i have removed the excessively heavy 1/4 inch ply servo trays and i will relocate the radio further forward than it was as the tank will be low to suit the laser and the normal tank bay will be open for radio and batteries. so it might all work out even, not sure at the moment. 

 

In any case though, i cant see it being much different to the way it was before and am aiming for 22 or less. 

 

One thing on the ballast. There is often great hysteria about models needing loads of nose weight or cries of incorrect cg on plans when in reality they just need to use lower elevator rates. If you balance the model further back you can get away with much lower elevator rates to retain the same level of sensitivity on the stick. A more aft c/g is very helpful as it makes it much easier to handle on the ground and will reduce the tendency to nose over. It also means the model is lighter overall due to the ballast left out. 

 

Warbirds do not need 45 degrees of elevator deflection. As i have said many times, my Sea Fury will loop on about 3mm of elevator so you really dont need much. 

 

 

Hi Jon,

 

Strange, isn't it?

 

There is a massive thread where I got that info

https://www.rcuniverse.com/forum/rc-warbirds-warplanes-200/7644110-complete-yellow-aircraft-spitfire-thread-24.html

 

So my idea using a reduction gear in conjunction with 240V does not seem a good one? Nothing to be gained?

 

 

Edited February 13, 2023 by Artto Ilmanen

[Artto Ilmanen]

Jon, what do you expect, how much your painting job is going to add weight?

 

I'm asking as I have been offered a YA Spitfire for 150€ and I'm tempted to buy as at least where I live you do not come across these often.  

 

No crashing but the model requires rebuilding as it looks ugly etc. But no fractures or cracs on the fuselage and the wing is also in good shape without any major accidents. Also, the bottom front part of the cowling is missing.

 

The original builder just sanded sanded the wing and then  painted and varnished it - no glass cloth whatsoever and the work was done very poorly, unfortunately.

 

Anyways, the model now weighs 5600g without servos, tanks and engine + plumping, electronics, spinner, etc. Also, no pilot included in the weight. My maths shows it could weight in ballpark of 18lbs when ready to fly  (how so little, maybe I need to tweak my math?). But, if I cover the wing with light glass cloth and then paint the wing I certainly add weight - but the question is how much? Any ballpark idea? I'm not experienced with this kind of painting projects.

 

I'm still planning to mount the 240V if I can keep the weight at this ballpark..

 

Few pictures to motivate you - as yours looks so much better 🙂

 

[Artto Ilmanen]

By the way, Jon

 

How are you planning to organize the cooling in your model? Decent baffling of course but ideas for air inlet and exit?

[Jon H]

150 euro? buy it. Dont ask questions, just buy it and run!

 

So, weight. Again, just dont worry about it. The one i have was about 21 or 22lbs last it flew and it flew like a pussycat. Dont loose sleep trying to make it super light, its just not that important with a bigger model. If its anywhere between 20 and 24lbs it will be fine. 

 

That model is clearly in need of some love and stripping the old finish is clearly the first job. With that gone you can deal with structural repairs and generally move forward. 

 

I do not find that using glass cloth adds much weight but i am extremely light with my resin. I use the lightest cloth i can get, 10gsm i think, and then thin my glass resin by 50% before almost dry brushing it on. I use as little as i can, and once done hit the wing with a gentle heating from a heat gun to evaporate off the thinner and help kick the resin. I then sand, thinned resin again to fill the weave, sand, prime, sand...etcDoing it this way adds almost no strength but i dont care about that. I just use the glass as a surface to take paint and nothing more. 

[Jon H]

Oh cooling. I plan to use the scale exhaust as the outlet as that is how the kit is designed but i have not got to that stage yet so have not looked into it in detail

[Artto Ilmanen]

Very well - I too was thinking of the scale exhausts for exiting the air but let’s see. However, the air inlet is also a matter to be considered. The scoop in the full size one seems to be too far below the wing to help with the air inlet. 

[Basil]

On 25/10/2021 at 22:14, Ron Gray said:

Should have used some Freddy's sauce Jon!

Ron, can you remind us of freddys sauce please.

Bas

[Jon H]

After a long time out we are back as my other Spitfire project is approaching paint and so the YA needs to catch up a bit. 

 

The wing is more or less ready for paint, but the fuselage needs work. 

 

First i carried on messing around with the engine, exhausts and cowl. After several configurations were tried i think this setup with the dumpy exhausts is a winner. I can now go back and make good all the chopping about of things and get the whole thing tidied up. 

 

 

 

Next i decided to cut an inspection hatch to see how the 30+ year old elevator linkage was doing. It seems fine, but it was worth checking. I also glued up a few loose hinges on the rudder. 

 

 

The next task was to give my pilot somewhere to sit. The previous builder did not open up the cockpit at all and instead glued the severed head of a pilot on top of the fuselage. This wouldnt do, so....

 

 

This infill is not scale, but needed for added structural rigidity

 

 

Rubber Johnny here is the wrong scale and i will source a 5th scale example when they become available. Everyone is out of stock 😞 

 

Again, the large balsa spars in the cockpit are not scale but needed for strength. I could have done it differently, but as this is a flying model and not a scale masterpiece the quick and dirty method sufficed. Once painted it wont show anyway.  

 

 

Canopy in place, still in its protective film

 

 

Next jobs are tidy up the engine/exhaust cuts as discussed, make good my inspection hatch and confirm control rod integrity, tidy up the cockpit cutout...sand, prime, sand, etc. Then paint with a bit of luck. 

[Artto Ilmanen]

Did you think of mounting the engine upright? 

 

My initial measuring shows the engine (Laser 300V) might fit quite nicely if upright due to the cowling being wider on the top than on the bottom. 

 

I'm thinking to use, maybe, a 300V, to have good performance but I would not like to harm the beautiful distinctive round shape of the Spitfire cowling if this could be avoided somehow. (like mounting the engine upright?). Maybe the engine could be better concealed inside the cowling vs. mounting the engine inverted?

 

see pictures - most likely some modification of the top section of the fuselage would be needed (a removable section?) would be needed to help with the installation and maintenance of the engine.