The Whispering Death

[MThemadhatter]

Having finished the Lysander it is time for me to move onto the next build. I shall be building the Tony Nijhuis 70 in Beaufighter

 

I am going to build mine as a TF-X with the thimble nose radome and extended tail fin in a coastal command paint scheme and I might add some under wing rockets

 

 

Its going to be electric with these motors Emax GT 4020/07. .

 

These will swing a 14*7 prop to look scale, powered by a 4 cell battery for each motor of around 4.5-5Ah. 

 

For retracts I will be using these  Eflite . I just need to source some scale oleos from some where.

 

The reason for using such a large motor on 4 cell is that all the advice I have been given is that it will need weight up front to get the C of G in the right place and to build the tail light.

 

I have also been gathering some reference material including the original build article and a book on modelling the Beaufighter which is an absolute mine of information.

Now this is the first time that I will be sourcing my own strip and sheet balsa from slec and I have a couple of questions. For the sheeting should I go for soft or medium balsa ? I am planning to glass it with the GF and epoxy from Fighter Aces. Also what's best for the spa material, spruce or obiechi ? I fly off quite a rough patch so the wing needs to be strong. However will normal balsa be ok for the spas in the tail plane ? remember the lighter the better a the back end

Edited By MThemadhatter on 22/10/2010 12:36:19

[MThemadhatter]

Should add the plan and cowl/canopy are here Beaufighter Plan

[MThemadhatter]

Ok

 

I now have wood, a lot of it shaped

And a nice tidy work surface. All I need now is a large bit of plaster board and contruction will comence.

 

I am going to build in this order

 

Tail feathers

Fuse

Wing

I am doing it this way so I can do the radio install in the fuse as I build it, so as to get the snakes and sevos in the best possible position

 

The first job is to modify the plan to shape the tail like this

 

I have some cross sections of the nose to work off, so I am goint to make a former to change the profile from the plan to that of the TF Mk X and then add dome shaped radome on the front. 

 

 

 

[Stephen Grigg]

Is this build going to be easier or more difficult than the Lysander

[MThemadhatter]

Hi Stephen, sorry for the delay in replying did not get a notification

 

On paper it looks  a lot easier, or more straight forward. I say this now before I get to the point of planking the nacelles No stringers, spats, or four piece wings !

Any way I have finally got the works space organised and managed to spend a few hours on it this weekend.

 

First up is the fin and rudder. I had to draw the dorsal fin on to the plan and took the measurements off the 1:72 3 views in the book and scaled them up. Then I cut the extra bits from 6mm balsa and then laminated it all together.

 

Just need to adjust the centre piece a little before glueing the sections and begin the process of sanding the bits to profile. The fin is shaped as to plan down to the top of the middle piece and the dorsal fin is shaped as shown in this handy picture below.

 

Which is a wedge shape, the centre bit is then shaped to transition between the two. A lot of sanding !!

 

Once this is done I shall build the rudder then move onto the vertical stabiliser/elevators

 

Here now I have a question.

The vertical stab is constructed of ribs with a two balsa spas at the front and rear of the ribs. The ribs taper towards the tips of the stab.

 

Now if I build them flat over the plan as it say in the build article, I will have a small amount of dihedral or dihedral built in to the halves depending which way up I build them. This is like they way it was done with the Lysander when you build  it up sided down and end up with a little dihedral. Or should I be building them symmetrical ? and if so how ?

 

The tow halves of the vertical stab, once built or joined together with a dihedral braces.

 

S

 

 

[MThemadhatter]

Well after spending the last 2 months doing overtime and putting this together

 

I have now returned my attention to the Beau

 

First off is the tail end

 

The vertical stab was built over the plan and then skinned on the bottom. T1 and T2 are missing as front and rear dihedral braces are used to join the two half together.

 

whilst this was curing I started on the rudder

The ribs in this picture are hard balsa to give a bit more strength at the high stress points. The rest are soft balsa.

I am not going to profile the horizontal stab till I have the fuse built as I have modified it.

 

Once the two the glue was set I added T1 and T2. T1 has to go in at an angle as the horizontal stab goes through the middle. The LE is being shaped here. I put black marker on the LE face so that I don't remove to much material, when its gone you have removed enough.

I then built up the elevators , this was made easier the riblets and been cut as they are shown on the plan.

Here it is slotted together. I will not do the tip blocks until I have hinged the elevator so that they are the right size. I did it the over way round on the lysander and ended with to big a gap between the fixed and moving parts of the tips.

 

I intend to make the hinges scale for the evelvators and rudder, like this

By putting to strips of triangle stock on the TE and then sanding them to a concave shape and then shaping the LE of the elevators. The only trouble is the vertical stabs taper towards the tip. Any one got any tips or suggestion on making the hinges this way ??

 

[Danny Fenton]

looking great, and coming along well too

I did show a way off radiussing the leading edge and doing neat concealed elevators/rudders on my TN Spitfire thread. It is simply a case of circles whose centre must pass through the hingeline. The diameter of the circle will equal the thickness of the elevator leading edge at that point. At the tips the diameter of the circle will be less because the thickness is less. The cntre of this smaller circle must still be the hingeline. I draw lines on the elevator leading edges to indicate the centreline and the 45 degree points, it is fairly easy to sand accurately then.

 

Hope this helps?

 

Look forward to seeing you build this.

 

Lots of building going on, definitely an upsurge in modellers building again 

 

Cheers

Danny

 

 

[MThemadhatter]

Thanks that is a lot of help What size of robart hinge point are you using ? I have some but yours look bigger ??

[Danny Fenton]

Glad it helps. I think they do three sizes, 3/32, 1/8 and 3/16, I have used the larger ones on the elevator but the 1/8 on the ailerons.

 

Robart site

 

Cheers

Danny

Edited By Danny Fenton on 15/01/2011 20:10:36

[MThemadhatter]

Looks like I will need to add about 2-3mm to the LE of the elevators to get the radius right, guess what I don't have in my balsa pile lol

[MThemadhatter]

Right I have my wood ready and I also picked up some larger 3/16 hinges as I don't think the ones I had are up to the job of elevator and possibly the rudder. I bought a load of triangle stock to make fillets to hide the hinges but having looked through your thread Danny I think I might go with with the proskin/ ply shroud instead. Reason being there is a slight taper along the length of the elevator and I can't quite work out in my head how this will work with a fillet, it seem simpler with just a shroud.

 

The next choice is whether to use conventional control horns or make up some from fibre board. I prefer the latter option as it will be less noticeable but probably not to easy to cut them all out

Started to price up the cost of the electrics today seems it will cost be somewhere between £220 - £300 depending on what bits I go for. A pair of Irvine 40's seem very cheap in comparison but I am not sure I would like it when one of them dead sticks

 

[MThemadhatter]

could not sleep last night so, spent a lot of time researching lipo's, esc and motors.

 

I am pretty sure that I will put these motors in it

 

 http://www.totemhobbies.co.uk/product.aspx?id=8270

 

I think although I am not completely sure that these will pull about 50-60A on a 14x6 prop, all the data is for 5 and 6 . My LMS sells these and I get a discount

For the ESC I want one that has the stop on obstruction feature, and the best value one I can find is from 4-Max

http://www.4-max.co.uk/pp-eesc70au.htm

 

In fact they recommended the following set up for the Beau

 

Motor        PPO-5055-580    £55.50

http://www.4-max.co.uk/ppo-5055.htm#580

ESC          PP-EESC70AU     £49.95 http://www.4-max.co.uk/pp-eesc70au.htm

Prop         JXF 14x7        £ 6.50 http://www.4-max.co.uk/jxf-props.htm

Battery      PPL-30C4S-4500  £72.99 http://www.4-max.co.uk/lipo-30c.htm

 

 

Now for lipos..... I need something of about 4500mAh to 5000mAh and by my reckoning at least 25C rating, that will give me  112 - 125A continuous rating which should be comfortable.

 

I am looking at getting some LoongMax ones from my LMS or the big fish. However I did see some nice Turnigy nano-tech 4500 and 5000mah 4S 25~50C Lipo Packs which would cost me about oh , £50 less which is a bit tempting. Anyone had any experience with these ?

 

Any way I did some balsa bashing today. Using Danny's method I started work on the elevators. 

 

I got this far and decided to fit the hinges and try it out. However my hinging tool was not big enough to mark the centre line or the holes for the hinges, so a Robart one is now ordered and once that arrives I can carry on. No that I am complaining as the weather down here in Devon has dramatically improved and I am going flying

 

[Danny Fenton]

Looking good

I have some nano Tech cells from Turnigy and so far they are holding up fine. Still early days mind.

 

Cheers

Danny

 

[Ton van Munsteren]

MThemadhatter,

Just to let you know Iam looking over your shoulder on thisbuild.

The Beau should make a great plane flying,have a smaller one myself and loving it.

Keep up the good work more photos please and did you received the Efilte retracts already.

Ton

[MThemadhatter]

Thanks Ton,

No I have not bought them yet, saving up for them I was going to buy them once I get to the wing. I am little concerned, ok a lot about where to the scale legs. I was going to get some from unitracts but they are no longer taking orders. TN web site is selling these

Of course I only need the oloes/legs but the wheels look nice.

 

Took a bit of a knock yesterday, this 

Was turned into this

By what I am pretty sure was RX failure. Not the sort of concern you want when putting so much time into building scale models

Edited By MThemadhatter on 20/01/2011 23:00:42

[MThemadhatter]

Well the weather turned bad and I have had some free time so construction has been continuing in dribs and drabs.

 

I finished hinging the elevator halves and cut out the tip blocks.

 

There are two extra bits of the balsa that go on the inside edge of the elevators but I am holding off glueing those on until I have dediced what style of horns to use. I will either use this sort

 

Or make some from fibre board and stick them to the inside edge of the elevators, so that they are less visible. However this is something I have not done before. Anyone got any tips or some pics ??

 

I then made a start of the fuselage. First job is to glue the fuse sides together

These came in two sections that have to be stuck together. Once these have dried I will swap the plans over and start on the fuse proper. I am going to wait until the fuse is complete enough to install the tail fins before adding the horns to the tail surfaces so that I can get the alignment of the snakes right.

 

[MThemadhatter]

Another quick post whilst I wait for things to dry.

 

I added the shrouds to the elevator today. However I made them a bit to big, but once I have profiled the tips I will cut them down. I also realised that I need to sand down the thickness of the elevators slightly otherwise they will be to thick once I had solartex to them. I used 1/64 ply for the shrouds

 

I then started on the fuse.

 

First I swapped the plans over and re-organised everything. Each fuse half has a birch ply doubler glued over the the wing section

 

These where glued in place. I then carefully marked out on the fuse sides the positions of all the formers and started by glueing F4 , F5, and F6 to one side. F4 and F5 are two part and I pinned these over the plan a tack glued some supports to hold them in the correct position.

 

I then stuck the other side of the fuse on and transferred it to my jig.

 

Once the glue is fully cured (how long do you think before I switch to CA ? ) I will mark the centre postioin of each former. I will then align the centre line of F4-F6 with one of the lines on my Jig. I will then be able to accurately align each former. I may also pinch together the ends of the fuse sides so they are level.

 

Now that I have got the fuse together I realise that I have enough room for 3 servos side by side.

 

I now need to start figuring out the snake runs and position of the servos. I will use one servo for each elevator half and one for the rudder. I am going to use Hitec 5485's as I have good experiences with these and they are affordable. I also need to work out where to put the retract servo for the tail wheel.

 

Right lets go see if its dry yet

Thanks again to Danny for the tips on the elevator construction

 

Edited By MThemadhatter on 05/02/2011 15:38:40

[MThemadhatter]

Still not dry lol

 

Other things that have turned up

[kiwi g]

Was the wood cut by you or via the plan cowl pack ,

[MThemadhatter]

I had a short kit laser cut for me, I don't have enough time/patience to cut all the bits out. Traplet sell the plan and cowls/canopy but no wood pack yet.

 

I discovered one slight omission on the plan, you need 2 of F6 so ended up cutting another one myself using the laser cut one as a template. Another thing I have realised is that the fuse sides are cut from quite hard balsa and its going to take some bending to get round the front 2 formers. I am now trying to find some ammonia solution

[Danny Fenton]

Looking good, I managed to pick up amonia on Ebay believe it or not

 

Keep going this is going to be a really fabulous model

 

Cheers

Danny

[MThemadhatter]

I found some in Boots for less than £2

 

I have just had to put a second order for wood into slec. I was an numpty and bought 10 sheets of 1.5mm and 5 of 2.5 when is should have been the other way round I took the opportunity to order some obechi for the spas at the same time, I will then make the choice of either spruce or obechi or a mixture lol

Edited By MThemadhatter on 07/02/2011 12:41:59

[MThemadhatter]

Ok some slow progress over the last couple of mornings

 

I am using aliphatic resin but as the loft is cold at the moment it's taking an age to go off. As a consequence of this and the stiffness of the fuse sides I found that if I tried to add more than two formers at a time it would upset the ones still drying. I like the aliphatic resin as it gives you time to move things and gives a strong bond as long as I leave it clamped for at least 4 hours.

 

I have started adding some other bits and pieces. First the mounting plate for the wing bolts to secure to from birch ply and triangle stock.

 

 

No messing about here, its been glued in with 30min epoxy, also added the cross braces as shown on the plan.

 

And here is F2 and my next problem

You can see the curve that the balsa will have to conform to. I have started experimenting with some stiff scrap balsa and ammonia solution. Any got any tips on the best way to use it ?

 

Once I have added F1, F2 and the servo tray I will take it out of the jig and add F2a and F6a. I am hoping that the servo tray and wing bolt mount will have locked the structure into shape.

 

 

[Danny Fenton]

Yikes I hate designers that do that. From where i am sitting you have a fair bend to put in the wood. If you brush the outside of the curve with ammonia and then gently tease the sections around, probably only a third, then let it set for a while, then brush more ammonia and go a bit further, you should eventually get the curve you need. The secret is to keep it wet and do it gradually. I use masking tape to hold it curved.

 

I cannot tell from the photo, but it looks like a ply doubler in the mix too? Crikey........

 

Cheers

Danny

[MThemadhatter]

I might see if I can prise the ply doubler away from the fuse side before bending the sides. The sides only have to bend around the top sides of the former as far as the flat bit. My ammonia is 10% should I dilute it down to 50/50 ??