A TN 46'' SPITFIRE by an Intermediate builder

[Henri Squier]

Hello everyone,

I'm in holidays for some days (hear : i'm for from working bench).

And what does an addict modeler when far from his balsa ? he is on an RC forum... (shame on me, shame on me)

At first :

Thank you Tony Nijhuis for offering this model.

and Thank you, thank you, thank you so much to Mightyspeeh for sharing his work that has been a tremendous source of learning. I how you a very very big skill upgrade.

I ordered for some days a 46'' Spitfire at TN web site and offer to follow its building.

So :

Why an other thread on TN 46'' Spit although such master thread already exist ?

1- At first it's a way to humbly feedback to Mightyspeeh and Tony Nijhuis, and contribute to this forum.

2- But mainly to give an INTERMEDIATE point of view to this construction : I'm far from being a master of building where everything seems easy and every post and photo look like art.

When I seen some posts I feel : Oh! my god, how beautiful it is but I never have the time / the skill / the drive to do it !

I'd like to share the "cost / effectiveness" of the technics I learned here.

(Please, please, please, forgive me but don't expect lush high tech photos)

3- Four months ago I underwent to build a 46'' spit from scratch deeply inspired by the two ones up. For some day and before final painting I wanted to test its flying ability. It flew, not well and crash the second day of testing. I don't have the mood to redo from scratch - that explain my TN buy.

I'd like to share my building experience and the mistake (a few ones !!) I made.

So to finish this initial post and because we, modelers, love photos here are latest build just to fix the skill level i'm from :

yes, when you finish it your proud like a lice (french saying) but after some master post you can found here you feel like a dust in the Louvre. Anyway, flew very well, buid in a WE.

Depron is OK but balsa flies better. Fly very very well (at 26 gr/dm2 it would have been a shame) a work horse to learn better flying and begin 3D. And unexpectedly crash crash and re crash proof.

A try to "de flat" the fuselage. Flew well but not better than could a 80 cm model.

Thank for watching, more to come, henri.

[Henri Squier]

Well...

Far from working bench, wife and daughters at christmas shopping... lets continue...

These planes (up there) were made for some years, then I had a stop in RC modeling. And I came back because of a major event / innovation : SKETCHUP !

I came back with this one :

I'm a traditional builder used to make 2D plans with paper and pen.

It's why the previous planes were all flat or with easy fuselage geometry.

This round one would have been impossible for me without sketchup.

If interested build adventure on :

**LINK**

But the problem with depron is this :

Get aged to fast (and difficult to repair)... this was just after a little heavy landing.

So after a while I (re) discovered the amazing beauty of the spitfire (here we come finally with spitfire on this spitfire thread !).

I (re) discovered it with D-Day commemoration in June, then :

read "Le grand cirque" of Clostermann

saw "the battle of England"

read "the last enemy" of R Hillary, "Spitfire Pilot" of Roger Hall, "Carnet de Guerre" of René Mouchotte,

and saw countless spitfire and battle of Britain documentary...

I never have even dare dreamed about it because of its curved lines. But now, with sketchup every thing was in place to give a chance for this dream to come true : Next plane will be a Spitfire !

Sorry, as said I'm in holidays and did not expect to open this thread so I have no pics of it but I promise there will come.

Anyway lets show how I went with sketchup :

This is the first point with Sketchup : be able to print the pieces to cut.

Yes I have to say it : Sketchup (as everything with computer) is very very very very very time consuming.

But (second point) it allowed me to virtually "dry test" anythings. So I could create and print (quite easily but again very long process) curves pieces or structures with weird angles it would have been far beyond pen and paper possibility.

So here are the spec of my late scratch Spitfire :

wing : 120 cm (46'' naca 2415 to 2412 from root to tip. +2° root and (I think this was the problem) -0,5° tip.

Tail : +0° (did need only a little down trim).

Electronics : PROTRONIK 2810 (88gr) 1200 (+/- 350 W) slightly under powered but I didn't expect the weight I finaly got, lipo 2200. Engine +2° down +2° Right.

E retract 10/15

Expected weight : 1100 gr (like Tony Nijhuis one), expected loading 45 - 50 gr/dm2

Real world AEW : 1650 gr !!!!!! , 61 gr/dm2 !!! (It clearly doesn't fly like a parkflyer !!!!!)

Bare fuse : 347 gr, Bare Wing 407 gr, Electronics 566 gr and and AND 270 additional gr for CG !!!

Why didn't she fly well ?? I will tell my mistakes and try to explain my hypothesis next time.

Well (has to prepare meal) ...

What I can say N°1

- Skechup is quite easy to use and master (expect some sea sick moments at the beginning).

- Yes It's hugely time consuming. But, for me, without it : no beautiful curves, no complicated angles : Sketchup took me off a lot of construction hazard and wondering.

- You get very happy when you print the pieces and I can attest it works unexpectedly perfectly.

- If like me you only take pleasure with self made plane (I know it's a problem... a real problem, (should speak about it with my analyst) RFT are much cheeper and far less time consuming) I recommend to try (just) once.

Thank you for watching, henri.

[Henri Squier]

Hello,

I have to admit, until now theses post aren't what expected by the title.

Sorry, I just hope not to annoy everyone.

This post will be the last before classic TN Spitfire build thread, I will 1/ Report fly and crash, 2/ try to make analysis 3/ explain my "user requirements" for the next TN spitfire to come.

1 : Flight and Crash report :

First day flight underwent at my usual flight location : a small unused country road (3m width) with is only flat paved over 30 or 40 m.

Flight N°1 :

Took off with with my usual CG location : 30 % of LE : Far too tail heavy. I immediately get concerned about landing and realized after one or two turn I won'y be able to land on the runway.

It could have cost the plane, I don't really know how I manage to crash land in the fresh plowed field with no hurt.

Flight N°2-4 :

CG moved forward with everything I had (extra lipo, stone, keys...).

For taking off I had no real difficulty to keep her straight on the "runway" but it needed far more the the paved portion of the road to take off.

Just after taking off underwent for all flights the same big rodeo (getting first left then huge instability) while she flew straight after.

I couldn't really enjoy the flights : They were quite fast , turns were still little heavy (still tail heavy ?), stall test underwent at reasonable speed but was a real stall with start of spin that needed active steering for recovery.

Everything told me I perhaps didn't owed the required skills.

DAY °2 - Flight N°5-7 :

I was only focused on landing. The new runway (10 x 100 m) was much more appropriated and allowed me to be much more comfortable with the speed of landing. I have to admit she was rock steady if I kept speed and I manage two nice and realistic landings.

But..

Still big instability (one very big rodeo) just after take off while the rest off the flight was straight ! ! ! ??? Why ??

Finally, not used with the wing loading, last back wind U-turn for landing was too slow. Stall, spin, crash.

2 : Analysis : One real question remained - after it's mea culpa.

- The real question is : Is the wing twist (+2° root, -0,5° tip) the origin of the big rodeo after take off (or just because i'm a bad pilot (indeed possible)) ?

after :

- Overvalue my pilot skills / did not take time to learn from other practice (Cf : Mightypeesh page 8).

- I was stupid to think I could maiden (and fly safely) on a 3 x 30 m runway. I knew a 60 gr/dm2 loaded plan flies fast and requires long landing.

- I spent four months for conception and building and Zero minute to check the accuracy of CG.

- Was sadly surprised by the amount of lead needed to achieve CG while a pre conception analysis could have told it :

I was surprised by the accuracy of of theoretical calculation : Real life lead 270 gr !

The excel page allows me to change the value :

If I build the Tail 60 gr (20 gr lighter) and the fuse 255 gr (15 gr lighter) the nose weight needed drops to 188 gr !!!!!

Thanks for watching, nest post will be classic build thread I promise (waiting for TN postage to come), henri.

[cymaz]

The joys of scratch building! I built a high wing plane from my own drawings..on and off it took a couple of years to get flying correctly. And a couple of engine changes!

Edited By cymaz on 22/12/2014 08:34:20

[Henri Squier]

Thank you cymaz, thank you for your reading and comforting,

Well, well, well, what came up today ?

but only the plan, as specified short kit and wood will come after (average 3 to 28 days (urgl !!!)).

As promised some pictures from late first Spitfire :

This was before unsuccessful attempt to master it ... and this is after only 7short flights :

Crashed into the only bush of the whole country land (explain so little nose damage whereas it was a straight down spin).

[Henri Squier]

some more :

Definitely I love this plane.

This will be one concern about TN Spit :

The lower part of the rear of TN's spit design is flat. Will I resist to make it round ?

Here is one (quite little) difference (15 mm) that could explain my excess of nose lead and over weight :

(but was initially a mk V project, does mk IX have longer noses ?)

And airfoil look more like Eppler than the naca 2415 I used.

All in all I'm impressed by the low number of pieces of TN design.

[Henri Squier]

Sharing experience N°1 : nose story.

 

When I decided to open this thread I was full of drive. But, now I can see it, also full of naivety.

Waiting to come home I read numerous of threads and posts :

I must admit it : everything has already been said, everything has already been written...

... tant pis ! as we say here on the other side of the channel.

Will perhaps help some one....

No spinner - no spitfire (in fact it's a joke because here we a joke here that says : non arm - no chocolate).

anyway it's true : no spinner - no spitfire.

The construction was quite advance and I did'nt solved the life-threatening vibration problem of the engine unit.

Even though I realize how stupid I was not to use an electric APC,

the (very) serious vibrations kept up. Well perhaps at 1/2 throttle more than 1/3 throttle but clearly kept up.

Notion changed regardless of the combination of spinner (ty1, A2PRO, Graupner, Topmodel electric spinner) and propeller mounts and the type of prop (10 x 4 to 12 - 5,5).

Finally this combination worked :

I think the point is the propeller mount and the weight of the spinner.

I think the first propeller mounting solution creates a to big mechanical moment that is incompatible with the not just perfect coaxial accuracy of the mounting+propeller+spinner unit.

The topmodel spinner (63mm) is 21 gr and only 3,60 euros !!!! (same price of 500x300 1,0mm acetate sheet : really no worth to try to DIY one's own spinner).

 

Sharing experience N°2 : leg story.

 

Late spitfire was my first plane with retract. Ironically I never used them during her short life !

Retract E flite 10/15, in France 70 euros, 52 gr each with light 60 mm foam wheel.

What I can say :

1- Work very well on the bench. Quite user friendly when in construction time.

2- DON'T do like me : a too small hole :

As said by (sorry, I forgot your name ) this undercarriage accepts nothing else than a perfect landing.

And if you are not Mister Perfect :

The landing bends back the U/C and the wheel stay outside. However you can easily bend it back (but how many times ?).

3- This undercarriage accepts nothing else than a perfect landing : bis.

The left U/C broke the first day after 3 landings :

N°1 was a controlled crash into quite soft waterlogged ground,

N°2 was a good landing but that ended on rough road (holes and small stones),

N°3 was a (quite) hard landing.

Surprisingly it broke went attempt to N°4 take off.

 

Well, i's getting dark...Thank's for watching, Henri.

Edited By Henri Squier on 26/12/2014 22:04:07

[WolstonFlyer]

Hi Henri, welcome to the forum.

Interesting posts so far, it is a shame about the problems with your own design spitfire, I will follow your build of the TN version with interest!

[Henri Squier]

Hello everyone,

 

Thank you WolstonFlyer for your support. I will begin with the wing as the ribs don't take part of the cNC pack.

 

This time I have a question about mounting retract legs into the wing.

 

The crashed spit was my first plane with retract and I was concerned about the mechanical stress of landing, so :

- I let the two side spars run until "W1"

- I added an extra short spar behind

- and finally doubled the whole box with 0,8 mm ply.

Far much complicated than what can be seen here (I hope GrahamC and Mightypeesh won't mind using their pictures, thank you to them by the way) where the mount seems only lying on the adjacent ribs that even appears not to be doubled !! ??

! ! ??

Are these light (my point of view) mountings enough ?

Do they handle vigorous landings ?

I unhappily experienced than my mounting is stronger the the E-retract system but it has a cost in terms of time and weight.

 

Thank you for watching, will appreciate any advise, Henri.

Edited By Henri Squier on 28/12/2014 13:52:34

Edited By Henri Squier on 28/12/2014 13:54:15

Edited By Henri Squier on 28/12/2014 13:55:56

[Henri Squier]

Hi everyone,

I'm still waiting the wood package ...

just while waiting :

On tony's plan (redrawn here) the tail plan and rudder are made with 4,5 mm balsa sheet.

It's impossible to do quicker and it's quite valuable in terms of weight. The rudder is 1,17 dm2, with light balsa expected weight is +/- 6 gr (light balsa 90-110 Kg/m3) : it will be my target.

It was however intended not to go into details (anyway, nothing else to do than waiting).

What should have been in one piece became in 14.

Weight check point : Ok.

Tony's rudder is 4,5 mm thin. In fact it looks better when a little thicker (this one is 9 mm thick). 4 gr in excess, ok I will be happy with it.

Happy new year, Henri.

[dave jamieson]

Hi Henri,

A man after my own heart here.I too love the Spitfire,Good luck with the build

[Henri Squier]

Thank you Dave, feels great to know I'm not alone with this obsession...

The wood pack came finally quickly.

First thing to fix :

I feed Sketchup with the scanned TN plan :

Allowing me to get this :

that came nicely together :

and finally :

 

 

Edited By Henri Squier on 06/01/2015 20:46:20

[Henri Squier]

I tried to resist .... but in vain.

The rear fuse belly won't be square.

In fact this former shape is the one used on the 62' TN Spit.

I thinned also a little the back.

I will so have two extra planking /60°/,  (definitely extra job, why, can't I leave the square belly ? are building thread a kind of therapy ? will it be sunny tomorrow ?).

 

Thanks for watching, i'll tell you how it went, Henri.

 

 

Edited By Henri Squier on 06/01/2015 21:05:40

Edited By Henri Squier on 06/01/2015 21:06:07

[Martyn K]

A great blog = I am enjoying this..

Martyn

[denis parkinson]

I have just bought the exact same plans, so I will be watching this with interest

[Henri Squier]

Hello to everyone,

Well...

Sorry, I know it's not the place here but I couldn't continue without a just few words ...

... just to make sense to the whole thing, I promise it will be short.

I have been deeply impressed by all my readings on WWI and specially with those on the battle of Britain. Deeply impressed by all theses women and men, English people and from all countries who fought at this time.

Because I love plane, because I like RC modeling, I decided the construction of a Spitfire. Over the fact she is stupendously beautiful it was a way to pay homage.

It could have been any of the Spit, but I chose René Mouchotte's one for obvious patriotic reason but also because I was touch by this 26 years old man who was sentenced to death by recently defeated France for escape from french army in order to rejoin Britain.

So, this one was my model.

Even though a beauty, truth is that it's a lethally weapon. But created to fight extremism, in a final design of peace.

I feel a strange connection I hardly can say in words with what happened for some days, especially for this satirical weekly, french and impertinent symbol of freedom ( think François Cavanna, main creator and editor, underwent nazi compulsory work service at 20).

They will thus take part in my thoughts and homage.

Sorry again for this aside. Lets now continue.

[Henri Squier]

Hi Martyn, Hi Denis, and thank you (and all other readers). you know, as a "newbies" it's always very pleasant to have such nice comments.

Well, back to work : The main question was how will I manage to make the "round belly" rear fuselage ?

Before that I had to glue the engine mount and fuse sides :

I made a hole for the LIPO in the first former :

In order to be able to place as forward as possible the LIPO :

I don't know yet if It will be useful or not.

After had to place the command lanes :

I'm happy not to have forgotten to do that before "closing" the belly (please can some one give me the correct denomination of this part of the plane, I feel stupid each time I use this word which always refers to me to "belly piercing" (just hope it's not the true denomination).

and then the funny part : trim the edges :

Yes I know, too dark (too dark to see...).

In fact fitting in the command lanes takes me always very long time.

And I had to glue together scrap 4,5 mm balsa sheet for the planking.

It's why the main object of this post is suspended !! Sorry just hope suspense is not too hard to manage.

Thanks to all, henri.

[Henri Squier]

Quickly, just for fun.

A "versus post".

TN tailplane VS Henri tailplane.

TN :

Pieces : 4

"construction time" : < 1 min.

weight : 21 gr. Let's say 16 gr after sanding.

me :

Oooops !!!

Pieces : too much !

Construction : A small afternoon.

Weight : 38 gr, and after sanding :

Well not too bad, let's say i'm happy with it.

Price of beauty :

Extra weight : 29-16 = 13 gr and 13 x 3 = 29 gr of extra lead in the nose so TOTAL extra weight = 42 gr !

A last little thing before goodnight :

TN tail plan and rudder is 33% bigger than the matched scale plan (my first spit). My first drive was to reduce it to scale size. But I remembered the "rodeo" instability just after taking off and decided to leave it as TN's original design.

His plane is known to fly well : I won't change anything in the aerodynamic design.

Thanks for watching, henri.

[Tony Nijhuis]

Hello Henri,

You are making a beautiful job of the build.

You are correct about the tail plane and fin being larger. For smaller models 'fishtailing' is a common problem so an oversized tail dose reduce the effect plus gives you more control.

For larger models around the 70" span, the problem tends not to be noticeable and so a scale tail can be used....keep up the good work

[Henri Squier]

Oh, thank, I'm very honored...

Here some more. Round rear second episode :

I had before to fix the tail wheel :

gave

and finally (Yes, it's not "scale", I would first like a Spit that flies, "scale" will likely be for the 62" ).

If we go on our little game :

TN winner with : Piece = 0, construction time = 0 and weight = 0 gr.

me : P = 9, construction time = little evening work, weight = 7 gr (+17 extra gr of nose lead ).

And finally,

And finally,

And finally,

the fun part ...

This square part won't be seen (under the wing fairing).

In fact something went wrong :

Although the former has not been moved of original place and has not been shortened (it's at the correct place on the top side), the last horizontal planking comes at the same level of the sides while it should come over it .

I will have to add a planking in order to "stop" the trailing edge of the wing.

Thanks to all, henri.

Edited By Henri Squier on 14/01/2015 23:03:19

[Henri Squier]

Hi to all,

Yesterday I looked Danny Fenton's thread "poor mans Spitty" .... in fact it's a kind of art engineering.

So I decided to up level a little the rudder.

I'm addict to Danny Fenton's close ups...

But close ups are without mercy and only tell the screaming gap

But don't misunderstand me, I'm happy. It drives me upward.

before sanding

after

Nice black background isn't it ?

Yes, there is a gap (in fact several), yes, close ups are cruel ....

Raw :

After dope (nitrocellulosic x 2 and sanding x 2) :

Just for fun 1 (Raw TN rudder and tailplane) :

Just for fun 2 :

This is from were comes the background ! henri.

Edited By Henri Squier on 17/01/2015 19:02:09

[Henri Squier]

Hi,

Yes, progression is going slow !!

I must admit : I had absolutely not enthusiasms for this part.

This was easy to do ...

... but didn't lead to anywhere.

In fact It took me endless time to decide how and where to put the technical access. Finally there will (probably) be two access :

one under (or up, or side of) the cowl (I don't think no engine access is reasonable).

one on the top in front of the cockpit (this one is sure : lipo access).

 

So, once done I had to wait having time to buy this :

Lead for cheap I found in fishing department.

I had the project to add them in the lateral 12 mm balsa sheet (cowl sides) in order to provision CG balance.

And surprisingly, unexpectedly, on raw (only engine and lipo) balance i got :

!!!!! (I would have bet for much more tail heavy).

 

So : What's the weight of tail covering and painting ???? (it will be glassed).

I bet for 150 gr (minimum) of lead needed for provision in the nose. What do you think ??

TN Spitfire builders ! How much lead did require to achieve your CG ??

 

Thanks for advises, Henri.

Edited By Henri Squier on 24/01/2015 00:06:50

Edited By Henri Squier on 24/01/2015 00:08:22

[Henri Squier]

Hi, some news ...

Finally 100 gr were chosen

Until now, cutting, fitting this in and gluing the two cheeks was, up to me, the most difficult (and unpleasant) part of the build,

provision for Lipo acces.

 

Remember I sand a little narrower the upper part of the fuse forms ?

The 4,5 mm side (TN ! You're foolhardy to imagine this could be bent !!!). 

 

With the original design I think this could harmlessly be done. 

With the narrower top the balsa sheet told me it did not like by a bilateral crack !

I think it has non incidence (i fill it in with balsa and glue).

 

Edited By Henri Squier on 31/01/2015 19:01:31

[Chris Bott - Moderator]

Looking good Henri.

Have you spotted the very long thread of Danny's about his TN Spit?

[Henri Squier]

Ah ! it begins to take form !

Sorry for the not finalized work and low quality photo but I'm in a hurry to show !

Remember, this was before :

After cheek gluing :

And now after (huge) first sanding :

Begins to look to what it's intended to be !

Sorry for the photo in the garage ...

After 7 years I finally acceded to my lady wish and took back the awful glued carped, sanded and varnished the parquet flooring.

As done (hear : no more dust that could be explained by the floor work) I was tool to be not allowed anymore to Spitfire in the living room...

... so, back to the garage.

I added an extra 3 mm at the top.

The good news is that it fits with the canopy of my first spit.

Very happy with the round rear fuse belly

I don't think I could have lived with a flat fuse.

Thanks for following, henri.

Edited By Henri Squier on 31/01/2015 19:24:32

Edited By Henri Squier on 31/01/2015 19:25:25