Topic: The Whispering Death, Beaufighter Build

Having finished building my TN Lysander it is time for me to move onto the next build. So  I have decided for another Tony Nijhuis design the  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 http://www.totemhobbies.co.uk/product/9dcdbc55-e7f1-4761-bb02-55ffa6b50c74.aspx
 
These will swing a 14*7 prop to look scale, powered by a 4 cell battery for each motor of around 4.5-5Ah. I have also considered some 3 blade vario props.
 
For retracts I will be using these http://www.totemhobbies.co.uk/product/0b1eb9cf-5232-456b-b5cf-918d49ebc756.aspx  . 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, and I shall get it 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

Having finished building my TN Lysander it is time for me to move onto the next build. So  I have decided for another Tony Nijhuis design the  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 http://www.totemhobbies.co.uk/product/9dcdbc55-e7f1-4761-bb02-55ffa6b50c74.aspx
 
These will swing a 14*7 prop to look scale, powered by a 4 cell battery for each motor of around 4.5-5Ah. I have also considered some 3 blade vario props.
 
For retracts I will be using these http://www.totemhobbies.co.uk/product/0b1eb9cf-5232-456b-b5cf-918d49ebc756.aspx  . 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, and I shall get it 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

As you are glassing the model soft sheet - assuming of adequate thickness will be fine. It has the advantage (obviously) of being lighter and also easier to work where curvature is needed.
Spars in the wing - spruce has a better weight/strength ratio than obechi. As I'm not familiar with the structure, can't comment on the tail spars.

Mike

i have these plans and they are on my "to build one day" list...

although it must be IC for me. 

I have built the TN Lanc and B17, I used spruce from SLEC for both with no issues, Tony's design would be fine for either wood IMHO, they are ace designs to build from 

I have built the TN Lanc and B17, I used spruce from SLEC for both with no issues, Tony's design would be fine for either wood IMHO, they are ace designs to build from 

I totally agree with the last bit, the Lysander was my first scale model and it was quite a complex build but the plans where good, and I like the way he builds things. I don't have the original plans in front of me a the moment, but I think the tail does not have spa's now, it looks like they use the TE and LE for the structural strength.

I love IC warbirds, but for my first Twin I thought I would go for electric. The cost of the power set up is about £200. I have decided not to build wash out into the wings, Tony says it flys fine with out it, and I want to keep the base structure simple so as to adorn it with scale detail. I planning on making the ailerons scale ie frise type with scale hinging. The elevator and rudder will be scale hinged as well. I am also going to use the same hidden hinging system that my VQ hurricane used to control the flaps.

One  thing I am starting to think  about though is how to control the elevator, as it has dihedral both halves will have to control seperatly so it looks like a snake for each half unless the is a clever way of doing it hidden. The rudder will be pull/pull.

I will put some pics up in a minute showing this.

RE the elevators, could you use one pushrod/snake and 'Y' off the end to each elevator? I have a 60" F3a style model that uses this method and works fine.

Mud 

Thats one of the thoughts I had, do you have a picture of your set up ?

This is what the full size alierons look like





I will have to simplify it a little bit  but you get the idea.

One thought I had on the elevators is if there is enough room is to run a torque rod in board of each half and have the connection inside the tail of the fuse, not sure if there will be enough room for that though.

Sorry I don't have a picture, but it's quite straight forward, It's a wire inner, which passes through a plastic outer that stops short at the 'Y' point back in the fus, The Y is another wire soldered to the original, they splay out to each elevator horn.

Mud 

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.

I have decided to go for a servo for each half of the elevator, I have 5 HS5485's out of a dead Yak to use. One thing I noticed was the weight of the spruce spas. I may yet use obechi for these as by calculations this would save about 150gr off the weight of the wing. Or use the spruce for the centre section and obechi on the outer sections.

Whilst I have never had cause to do any comparative testing, I wonder if obechi is comparable in strength/weight to spruce? Might it be better to use smaller section spruce rather than obechi?
Mike

TBH the plan states "hard balsa" for the spas and the ribs are all but for the size of spa shown on the plan  so obechi should be fine. I was going for "over kill" with the spruce. My lysander wings where made with obechi spas and they turned out to be pretty strong 

And as some one pointed out to me the other day, strengh in design and not materials. Also the strengh is in the joints between the spas and everything else.

 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 anhedral or dihedral built in to the halves depending which way up I build them. This is like they way it was done with the TN Lysander when you built it up side 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.

Well after spending the last 2 months doing overtime and putting the sbach 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 ??

Looking good
Mike

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 decided 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.

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 position 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.

I also received the cowlings and canopies 









The cowls are really nice but there is no frame work on the canopies ! so a bit of work to do there.

Right lets see if its dry

nice project...looking good.....

Although I'm on a Minimoa glider project, the fuselage length is similar-ish!. The plan suggested a pushrod for the elevator from a servo mounted in the cockpit area. That is about four feet! So I instead have mounted a servo in the rear fuselage to make a much more positive connection. I wonder if you'd be better off doing the same, although of course you'd be mounting two side by side. I've used a small metal geared servo for mine. The rudder is closed loop.

There is very little plane in front of the C of G



TN warns about making the tail light or add the church roof to the front so unfortunately its not an option. I am going to use a separate servo and snake for each elevator half and drill holes in each former to support the snakes which should stop any slop issues. Rudder will be pull pull. Still pondering the choice of servos I have 3x 5485's spare but the wing will need 4 servos, 7 digital servos on a 2/3 A battery pack ??

I built one of these a few years ago and powered it with two irvine 36's and it flew very well with no vices. I cannot remember any details of the build but after seeing your excellent build on here I can feel the need to build another one soon. Can I ask where you purchased the cnc parts from please as I cut out my own last time and it looks so much nicer if its done for you .  Ian

There is very little plane in front of the C of G

 Rudder will be pull pull. Still pondering the choice of servos I have 3x 5485's spare but the wing will need 4 servos, 7 digital servos on a 2/3 A battery pack ??

I have the same problem mate; the difference being I don't have two motors forward of the c of g. The c of g is just forward of the wheel and just aft of the LE. It was just a suggestion, as you've a distance there to keep nice and tight. The radome is nice and spacious too, what about sticking your rx battery(s) in there?

I sent the plans off to Belair and they cut everything that is not sheet or strip  If you go that route I would suggest asking them to cut the fuse sides in soft/medium balsa. Mine are of quite a hard balsa and I will have quite a job shaping them around f2 and f1. I  am now on the hunt for some more ammonia solution.

I had not thought of putting the RX battery in the radome, sounds like a good idea   

I am also toying with the idea of making a removable cockpit section under so you can lift off the canopy and hide the switches underneath.

I have the same problem mate; the difference being I don't have two motors forward of the c of g. The c of g is just forward of the wheel and just aft of the LE. It was just a suggestion, as you've a distance there to keep nice and tight. The radome is nice and spacious too, what about sticking your rx battery(s) in there?

Forward of the wheel? If you mean in its 'down' position - can't be, or the a/c wouldn't stand on its wheels.
Mike

Forward of the wheel? If you mean in its 'down' position - can't be, or the a/c wouldn't stand on its wheels.
Mike

Hi Mike. The wheel on the Minimoa is fixed. Unusually for a glider, (which has a single centre mounted wheel, usually) the cg is forward of the axle-something I wasn't aware of until I had the plans opened out. I'd seen Moas at fly-ins and when the wind got up I saw them pitch forward rather than back, it didn't occur to me it was because the fulcrum was behind the c.g. The nose moment is very short and finding uranium is a bit of a nightmare. (sorry to inadvertently hi-jack the thread)

. I  am now on the hunt for some more ammonia solution.

Max, go in to Totem, not the model shop, the hardware shop and you can pick up household ammonia,....That's what I used last time I was bending wood,.......Oh, and say hi to Shaun for me

Ian.

Thank's Walts had not thought of looking there  I got some today from Boots of all places for £1.80  just as well every time I go near Totem I give Kev money 

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. I decided to drill the holes for the blind nuts once the wing is built and the holes put in that. This way they will line up properly 
 
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. 

Presumably the ply doubler has to conform to the former as well as the balsa? Looking at that, the ply outer grain runs against the curve? How thick is the combined ply/balsa? I've managed to curve 1/32 ply over a large ish radius and that's in four separate parts (two top/two bottom).

Yours looks quite a tight radius to conform to with a quite thick skin.

The Ply is 1.5mm and the balsa is 4mm, if only I had realised before sticking bits together, oh well I like a challenge 

Having never attempted to bend that thickness around that radius I don't know if it's possible; but I suspect not now you've already stuck the ply on it. I've seen it done as a lamininate using thin sheet to allow for the inner/outer distance and then finishing with glass cloth. I guess if you need the ply doubler (two out of the three grains running fore/aft to maximise the flexibility), that would go on the formers first, and then build out with balsa sheet (1/16?). Leave over size on the balsa and trim/sand down to shape later. Good luck anyway.

Its only the top sides of the former that the fuse sides have to conform to. What I might try is slipping a knife between the doubler and the fuse sides and see if I can ease it off and then re-glue it once the I have done the bending  Here's hoping this the balls up of this build 

I had a quick look at this today on your club forum Max, but didn't have chance to get involved. As Steve says, to be honest I'd have pre-bent the balsa then attached the ply doubler similar to what I done with the GAD b17. Also Is that the way the kit was cut for you with the grain running vertical on the ply doubler? That seems to be completely against the grain (Pardon the pun) to how it would normally be done, and very counter productive to aiding the bending of the fus sides around those formers! You could try coaxing the sides around those bends, but the tendency might be for the sides to split at the wing saddle just outside the ply doubler.

Hi Mike. The wheel on the Minimoa is fixed. Unusually for a glider, (which has a single centre mounted wheel, usually) the cg is forward of the axle-something I wasn't aware of until I had the plans opened out. I'd seen Moas at fly-ins and when the wind got up I saw them pitch forward rather than back, it didn't occur to me it was because the fulcrum was behind the c.g. The nose moment is very short and finding uranium is a bit of a nightmare. (sorry to inadvertently hi-jack the thread)

Steve
sorry - I misunderstood. I thought the comment referred to the Beau.
Mike

Thanks Walts

It might not be as hard as it first seemed, just difficult lol 

 I managed to separate the ply doubler from the fuse sides
 

And I suppose if the grain was the other way on the ply it would not bend in so easily, rock and a hard place ?

I then soaked the sides of the fuse in water and placed F1 and F2 in position but did not glue them in. I then used the jig to hold the fuse sides in position. As you can see the left side is flexible enough to go round the former, the right side is a lot stiffer.



I am going to leave in the jig till tomorrow. I will then glue f1 and f2 in position with epoxy so that they wont budge, take the whole lot outside and then put ammonia on and bend them to the shape of the formers and use medium CA to glue them.
 
Whilst that was stuck in the jig I turned my attention the servo tray.



I cut out a bit of cardboard put it in place and then tried different arrangements of the servos to see what would fit. I have settled with the two elevator servos on the outside with the arms facing out and the pull/pull rudder servo in the middle. The mini size retract servo for the taill wheel will go behind the main servos. Just need to cut the servo tray from 3mm light ply decide how to mount it and see if I can save any weight from it. On thing of slight concern is that as shown on the plan the servo arms would be very close to the wing plate.

Well what a nightmare F1 and F2 have been
 
I glued the bottom of the formers to the flat section of the fuse sides. I then used the ammonia to soften the wood but it did not soften that much. I then with much effort manage bend both sides around the formers. At which the softer right side split whilst the stiff left side did not
 
Any way I think I can rescue it




 

The major problem was that wetting the fuse sides pulled the hole lot out of alignment so Its had to go back into the jig. Also the right side in the picture bent at a more sharp angle at F3 than the left side. The only other option is to get the fuse sides and formers cut again for me and start again Now waiting for the fuse to dry. I might leave it in the jig until I have sheeted the top of the fuse to "lock" it in position.

Welcome to the joys of scale modelling Max!,.....Why do you think most ARTF's are so box'y Did you fully soak the outside of the sides then let it soak in  for a long time before starting your bend. With thicker wood like this you really need to be incredibly paitent and just go for a little bit of bending at a time with lots of resoaking inbetween each tweak of the bend, but of cause, having the right grade wood for the job in the first place helps imensely. Keep at it mate, you'll get there

Yeah I spent a good 40mins soaking and then bending the sides, it was almost to wet  I also tried applying heat to the inside sides. The main problem I am having is keeping the arc of the bend even on each side of the cockpit/nose are around  f1 f2, I don't want a crooked nose. I am soldiering on for the moment 

Nah it's buggered



 I am going to have to start again and build a second fuse  The balsa is just to hard. By trying to get it to conform to f1 and f2 its now buckled down the sides of the fuse and I cant get it to centre properly on the front. I will have to phone up belair and see about getting the fuse sides and formers cut again but with the fuse in a softer grade of balsa. 

Only a week of construction lost though

I made the servo tray and worked out the snake run, so at least I won't have this bit to do again

A couple more pics of the problem.









What to do, finish off the nose section and see what it looks like or start again ? It would be nice to have a straight fuse after all the effort I made into keeping it straight