Warbird Replicas Spitfire LF mk IXc

[Andy Gates]

You caught me on a good day then

[Andy Gates]

Hi folks,

 

Has anyone noticed the aileron horn geometry is incorrect and has anyone had adverse flying issues?

 

Explanation of the above comment.

With the horn placed behind the hinge line on the aileron - deflections are such that there is more down movement than up which is the reverse of the normal requirement, unless people are programming this out on radios or they are setting the servo arm forwards of centre to counteract this of course.

 

I will make my own aileron horns so no big issue, just thought I would ask.

[Trevor]

Assuming the horns are on the underside of the ailerons, setting them back from the hinge line will give you more up than down. Maybe Richard did some rewiring when he was in your head??

[Andy Gates]

You are right, I crossed ends of angular movements. Doh!

 

Another question, I have tried placing the lower skins on the wing and I have a position error with the undercarriage mount position - which can't be wrong as it sits in the ribs. If the plate was the other way over the retract would not fit in the rib recesses.

 

The wheel well seems to line up OK, the aileron servo cover lines up (or there abouts), I am using the wing aileron spar as a guide to reference from and the root and tip ribs line up. LE is on the money and TE overhangs slightly and will need sanding as anticipated.

 

I tried switching skins and have the same issue.

 

The alignment is about 1/4" (6mm) out, pencil lines are where it wants to be.

 

Have I gone wrong somewhere?

Edited February 28, 2021 by Andy Gates
clarification

[Paul Johnson 4]

No aileron problems with mine..

The gear.... 

You'll have to do a little trimming but what you take of the front move to the back to fill the void. It depends on what retracts/oleos/wire legs you use. You'll want to infill the space between the top/bottom skins to stiffen it up as without that it's a little fragile. Same as the P51 kit

 

 

[RICHARD WILLS]

Not sure whats happened there Andy . If you kept the cutouts then glue them back in and iron a piece of brown paper over the area then re cut the hole where you think the wheel will retract . My wheel well is right up to the spar like yours , so to may just need enlarging 

[Jonathan S]

What i want to know is how you got such a beautiful shape.  My circle looks like something my 4 year old drew

[RICHARD WILLS]

Compass cutter . They cost £5 . Made of plastic usually red or yellow . Comes with three blades . 

Mad4tools has them at £2.75 

[RICHARD WILLS]

BTW . In the pursuit of losing weight at the back end , I have experimented with various versions of tail feathers . So far I have tried built up with 1/16th sheet , blue foam core with just leading and trailing edge and of course just using plain , light 5mm balsa . 

To be honest , there is not a whole lot between them . You can save a bit by replacing the elevator joiner with a piece of hardwood and two cocktail sticks . Plus , it is fun to make the elevators and rudder "Brian Taylor style"  ie with a 1/16th sheet core and little ribs.

The version in the picture below is blue foam core stab , with BT style moving parts , wood joiner . 

The other main area is covering , paint and glue . This set has plastic laminate film on the rudder and elevators which , with the build style is very light . The Stab is just blue foam with balsa edges and covered in brown paper and pva . 

The whole lot shown weighs 63g . 

I would also advocate chopping away almost all of the central crutch aft of the cockpit , leaving only the barest of frame to stop a banana. 

Of course , all of this is to see if a Mk1 short nose spit can balance without ballast . All indications so far are very possible . I will be using push pull fishing line on the rudder and only a little of the outer pushrod for the elevator . 

[David Hazell 1]

Carbon tube joiner maybe, instead of the piano wire one?

 

[RICHARD WILLS]

Yes David , Carbon tube is perfect . If possible you need to have a U shape which on the hardwood one can be achieved by drilling horizontally and then glueing cocktail sticks through to "drive" the elevators . 

If you simply glue the tube to the elevators , there is a danger that a bump in the car will crack the joint . 

Guess how I found that out ........................  

20 years ago , first flight, own design 190 . (my fifth)  must have cracked it in the car , but it still moved when I wiggled the stick . 

4 minutes into the flight , and marvelling at how well this latest variant flew , six foot low pass, did an immediate flutter which had the same effect as full down elevator ,...................Confetti 

 

[David Hazell 1]

8 minutes ago, RICHARD WILLS said:

Yes David , Carbon tube is perfect . If possible you need to have a U shape which on the hardwood one can be achieved by drilling horizontally and then glueing cocktail sticks through to "drive" the elevators . 

If you simply glue the tube to the elevators , there is a danger that a bump in the car will crack the joint . 

Guess how I found that out ........................  

20 years ago , first flight, own design 190 . (my fifth)  must have cracked it in the car , but it still moved when I wiggled the stick . 

4 minutes into the flight , and marvelling at how well this latest variant flew , six foot low pass, did an immediate flutter which had the same effect as full down elevator ,...................Confetti 

 

 

Thanks Richard! Ahh that sounds like a good learning experience! 

 

For my tail feathers, I think I will use my 30micron laminate, I may very well also source a carbon rod to replace the piano wire, or maybe even alu tube... I've already dremelled out significant parts of the crutch. I haven't touched the model for a couple of weeks, so need to get back on it, but life with young kids keeps getting in the way!

[Jonathan S]

17 hours ago, RICHARD WILLS said:

Compass cutter . They cost £5 . Made of plastic usually red or yellow . Comes with three blades . 

Mad4tools has them at £2.75 

 

Richard, I even have one of thoes, never thought to use it

[RICHARD WILLS]

There are even spare blades hidden inside it . Clever .

[David Hazell 1]

https://www.spitfireinmyworkshop.net/spitfire-mkix.php

 

Just WOW... Check out the gallery. What a master.

 

Mr Wills: I notice in the kit that the elevator doesn't have the 2 angles at each tip, just the one. Is there any reason for that, or is it that some versions of the IX were like that?

[Paul Johnson 4]

I have the drawings and book he refers to. If your a spitfire lover its a must buy.

[David Hazell 1]

28 minutes ago, Paul Johnson 4 said:

I have the drawings and book he refers to. If your a spitfire lover its a must buy.

 

It's quite a steep price, I do think the Spitfire is a beautiful looking and sounding plane, but I think the warbirds replica will be enough to satiate my needs! ?

[Martin Harris - Moderator]

If I'm not mistaken, the model referred to was on display at Hendon the last time I was there and looks incredible.

[RICHARD WILLS]

Ive got the Book . It is expensive , but you can see most of the pictures on line . 

David , regarding the double angle on the elevator . You are quite right . I have some wonderful drawings here at 1/8th scale of the MkIX Spitfire showing the elevator ends with two distinct angles . (It also shows early and late rudders ) 

However , the expensive book mentioned above shows the Mk 1 as having a simple elevator as in my kit . 

There are many pictures of Scale models and three views of MkVs with the single angle too . 

I guess that perhaps all of the early IXs derived from V airframes were of one type and the later IXs of another .

[David Hazell 1]

Nice! I'm going to shape it with the double angle, go me!

 

[Paul Johnson 4]

10 minutes ago, David Hazell 1 said:

Nice! I'm going to shape it with the double angle, go me!

 

Mmm reminds me of that song..... "There will be trouble ahead..."

 

[David Hazell 1]

1 minute ago, Paul Johnson 4 said:

Mmm reminds me of that song..... "There will be trouble ahead..."

 

 

Haha, why should it cause issues?

 

[Paul Johnson 4]

Yoda is one to follow.. don't go down the dark side.....

A Hurricane builder reduced parts to be 'more scale' that particular model isn't as friendly as it should be...

 

 

[David Hazell 1]

25 minutes ago, Paul Johnson 4 said:

Yoda is one to follow.. don't go down the dark side.....

A Hurricane builder reduced parts to be 'more scale' that particular model isn't as friendly as it should be...

 

 

Noted, sir... I wonder if Richard will comment here...

 

Another question, about how much to remove from the bottom rear fuse... See pic to make sense of it:

 

 

 

On the plan, where I've got a pen and a pencil pointing to, there's a hatched out section. I assumed this is to be removed in full prior to giving her an eggy bottom. Is that right? You can see where I've gone at the bottom deck immediately aft of where the wing will sit with the rough side of my permagrit. I've drawn lines that match what's on the plan. My idea was to uniformly sand off to the blue line before starting to shape the curve. Would that be the correct approach?

 

Thanks!

 

[RICHARD WILLS]

I know what Paul is referring to, but I think in this case , you are not reducing the over all area , so it shouldnt be a problem . 

Perhaps somebody will come up with the definitive answer to the two elevator types . 

Regarding the bottom shaping : really go for it . To do a proper job , you need to be sanding well into the triangular wood section .

As you say , the shape is that of an egg . If it gets a bit thin , stop, but dont panic as brown paper and pva will make it tough .