David Boddington Centurion (4th try)

[Alec Turnbull]

If you chaps here like traditional types of models then you may like this build.

This is my forth (as in the title) Centurion, I started the first one in 1980 when first published in the October 1980 RCM&E, however I didnt finish it for reasons long forgotten, years later in about 1997 I was thumbing through the RCM&E plans guide, that I had found in the newsagent on the way to work one day, I spotted the long forgotten Centurion and vowed to myself this time I will get it done.

It took a while, newly remarried and a house move from Kent to Blackburn, Lancashire.

Here is the completed airframe in the cellar of our old Kentish house

[Alec Turnbull]

Once the house move was completed, and my son was born, new kitchen done......so busy, I managed to complete the model, fitted with an SC91 (which if I remember correctly had a very low serial number 0002 stamped on it) any way it ran perfectly and flew very well indeed, radio was my old Futaba Gold 35mhz.

I passed my A with this in about 2000

Here it is in the garden of our old house in Blackburn, and at Pleasington, home of the Blackburn Model Flying Club just about to have its maiden flight.

[Alec Turnbull]

A couple of years later work took me to France for a few years, so no more aeromodelling for a while, when we came back to England I had such fond memories of the centurion I wanted another even though I could not spare the time due to work and kids, I had two now.

So I built a third one, this time with a RCV91 four stroke and my old steam powered Futaba Gold, unfortunately no photos remain of this one as I had gone digital and the files have since vanished.

Work was mad, kids needed attention, schooling etc my wife was not keen it was just the wrong time so that one went via E Bay.

Now I have finally retired and have plenty of time, my wife's attitude to model aeroplanes has mellowed ( a little bit anyway)

Leading up to my retirement and since it seems that model shops have all but dissapeared  I bought as much balsa and R/C job lots as I could find on E Bay and Facebook market place, my garage is now an Aladdins cave.

Retired in September this year so I have made a fair bit of progress, I have not taken too many pics as I has all been done before.

The basis of the start is a plan pack from DB Sport and Scale, which includes a plan ( which must have been drawn for a kit at some time as it does not show any wood dimensions or shapes of formers etc.) a set of the main wing ribs laser cut and a set of templates printed onto label sticky back paper.

Here is the fuselage being dry fitted, already making mistakes here and a big one that I had to sort out later!

[Guest]

Alec

This was mine from 2005,waffled around like a big trainer.

 

[Alec Turnbull]

I already had the original David Boddington RCM&E plan which helped with the wood sizes etc. The DB Sprort and Scale plan pack has a completly different wing fixing system, so the two plans are required to get the whole thing done.

I decided to go electric on this one, now I am a complete newcomer when it comes to this way of powering a model  lets hope I have done the right thing!

So on to the jig

[Alec Turnbull]

9 minutes ago, Jim Carss said:

Alec

This was mine from 2005,waffled around like a big trainer.

 

Lovely I hope mine come out as nice

[Guest]

👍

[Alec Turnbull]

Next is the wing mounting box on the upper part of the fuselage, the original design used 1/2 wooden dowels, which I can remember took a lot of careful lining up, the later amended plan has a much better tongue and slot arrangement which is more or less self jigging

Edited November 9, 2022 by Alec Turnbull

[Alec Turnbull]

Now as I said i am going electric this time, the motor I am using I picked up at a swop meet, keeping my fingers crossed it is suitable, it is a Turnigy 500kv supposed to turn a 18'' prop, I am going to use a 16'' ( cos I have it in stock!) so it should be OK.

Of course an electric motor is much shorter than a glow motor so I made a  mounting box from plywood, first (as I was not sure what I was doing!) I made a proof of concept out of cardboard, that went well so the wooden box was completed.

I seem to have neglected to take a photo of the completed motor mount, but you get the idea, it did come out ok, the prop lines up nicely with nose.

 

[Alec Turnbull]

With the fuselage more or less complete, time for the tail, using the paper patterns provided I cut out the parts and dry flitted them altogether, once I was happy with that I glued it up, cut out the rudder and elevators and sanded them to profile and test fitted them, looking like an aeroplane at last!

One modification I decided on was to substitute the balsa spar in the stabiliser for spruce strip, firstly because the wood stock I had was too soft, I felt, and on my original model a gust of wind tipped it up when parked in the pits and broke the stabiliser in half, so I thought a bit of extra strength would not go amiss.

[Alec Turnbull]

Undercarriage next, not my favorite job. To make life easier I invested (!) in a wire bender, unfortunately on the second bend it broke! cheap Chinese tat, I have had it welded up at a local engineering work since, but in the meantime I had resort to a big vice and a hammer in the time honoured method.

There are no proper drawings on the plan for the undercarriage so its a case of using what info there is on side views and plotting the final sizes, easy enough. I used a simple jig on a piece of scrap ply to get all the wires in the right place for soldering.

The plans show balsa spats over the wheels, I did not bother with those on the first model I built but I did make them on the next one and I have done so again on the new build, lockiny amongst the balsa job lots that I managed to buy were some big lumps of block just the right size

Cut the block using my band saw and carved and sanded them to a nice aerodynamic shape

[Alec Turnbull]

Next the wings, very straightforward, starting by laminating the wing tips from ply faced with balsa, then laying it all out and glueing up, there is a lot of it and two to do of course, once done they were given a final sanding, wing tip profile and leading edge all very satisfying

[Alec Turnbull]

The wing struts are made next, these are structual and need to be accurately made, laminated out of 3 pieces of 1/16th ply with ali tips bolted the underside of the wings and fuselage.

A trial fit, and thank heavens I have got it right! (more or less)

[Alec Turnbull]

So the Centurion is now complete, in terms of construction, the radio gear is in,the motor and speed controller are in and working.

I am using the Turnigy 80 amp esc and having read the instructions on programming it, I still had no idea how to do it, anyway someone must have been there before me and It was set up already so happy days! using a 6s lipo.

Just got to cover it, make up the glazing and do some fancy decoration, not decided yet.

So time taken about 6 weeks of a couple or 3 hours a day, weekdays only, weekends are for the wife!

Very happy with it so far, if the electric gubbins does not work out I will cut off the nose and fit a nice four stroke of some sort.

Thers pics taken this morning, had to open the garage door as it was too big to get round and photograph properly.

More pics to come when it is covered

[Jonathan W]

That looks lovely. Many years ago, my father built a DB Expo 80, which is very similar but with a smaller 80" wingspan. It was amply powered by a Merco 61. He did fit ailerons to the Expo. I see you have kept the Centurion rudder steering only. Do they handle OK like that?

Edited November 9, 2022 by Jonathan W
spelling

[john stones 1 - Moderator]

Very nice Alec. 🙂

[kc]

Really nice workmanship.

 

No ailerons but rudder only!   Quite a small rudder too ( typical Boddington ) with not much dihedral.  Presumably the others flew well like that?

 

[Alec Turnbull]

14 hours ago, Jonathan W said:

That looks lovely. Many years ago, my father built a DB Expo 80, which is very similar but with a smaller 80" wingspan. It was amply powered by a Merco 61. He did fit ailerons to the Expo. I see you have kept the Centurion rudder steering only. Do they handle OK like that?

I did consider converting the wings to aileron, but in the end decided not to, I thought it would entail more effort to redesign the wing for no real benefit, my original models flew perfectly on rudder only.

There is 3'' of dihedral each side it doesent look a lot, the Centurion is a nice steady slow flyer, very stable. I used to do loops and stall turns starting with a bit of a dive to gain momentum, quite majestic. Looking forward to having another go, but it will probably be in the spring next year.

[Alec Turnbull]

It just occured to me that I hadn't weighed it, so popped into the garage just now and stuck it on the kitchen scales, including the lipo it comes out at exactly 11 pounds, so once covered should be under 12lbs

[Jonathan W]

Must be a really low wing loading! If you like how it flies, that's all that matters in the end. My dad's Expo 80 always looked really good in the air.

[Alec Turnbull]

Covering is about to begin, the plan does not show any detail or a template for the windscreen (much like the undercarriage, you just have to work it out) but before I start I thought I had better make my own template now so as not chancing to damage the new covering, on my previous Centution build I had a template left over from a Flair Cub, so I just enlarged it and that did ok, unfortunately long gone, I used my CAD system to design the screen!

 

[Alec Turnbull]

That came out Ok with very little effort, transferred the patter to some polycarbonate sheet and cut it out, I cut it a little larger than the pattern so it can be trimmed for an exact fit.

[Alec Turnbull]

I was lucky to obtain almost 6 metres of Solatex, I am not entirely sure of the colour name it is either Antique or Linen, it gives me the basis I am looking for, for a classic aircraft, still not decided on the final coloured decoration.

Virtually all 6 metres were required, but not enough for the wing struts, since the colour is so close to the tone of the wood I may just sand the struts and varnish them with water based clear varnish that I already have available.

I have never used Solatex before, it goes on easily shrinks really well using my Protech Iron and a domestic heat gun, which when set to the lowest heat 300c and keeping the heat gun moving worked perfectly.

Took me three mornings to get it all covered, now I have put all back together again.

[Alec Turnbull]

Trial fit of the windscreen, so much stiffer than cardboard so when the time comes to glue it on I will have to use a bit of heat to get it to fit well.

[Alec Turnbull]

Christmas has come and gone, my wife is back at work so I can now turn my attention to some decoration for my new Centurion, its minus umpteen in the garage so I am now working in the dining room!

Solalac, (which I have always used before) is no longer available, at least not in the colours I require, searching around in the local bargain shop I found some paint to experiment with, its water based so very friendly to use, ease of brush cleaning etc and most importantly no smell.

I was looking for a slightly darker red, but this was all they had so I tried it.