Cessna 152 Aerobat

[Tony Bennett]

now that looks impressive sir.

can't wait to see this one come together.

[john stones 1 - Moderator]

Cowl looks well Richie

Nice blog very impressed, kit looks a cracker as well.

John

[Richie Carey Maddog Designs UK]

Well following a socially active bank holiday Monday and a stinking hangover yesterday it’s back to the job in hand. Its time to make the decking, start with a block of polystyrene foam.

Now mark out the blanks you will require, the Cessna has 5 decking’s so I will requires 5 blocks.

Once you have marked and drawn you cut lines on the foam you will need a couple of straight edges (I use two old light-ply fuselage sides from my Hammerhead kit) apply some double sided tape on one side of you straight edge, remove the backing tape and place on the cut line.

You will also need to add a few pins to hold your straight edge in place, one you have a straight edge on each side of the foam you are ready to cut.

Place some weight on the foam bock to stop it moving.

And cut.

Once you have cut out your decking blanks you are ready to cut out the decking’s, for this I build decking jigs with a cutting profile at each end, I do it this way because I will be cutting a lot of decking’s for my kit’s and they all have to be identical, however if you are going to be cutting one set of decking’s or indeed if you only require one deck then you can just stick (double sided tape and pins) cutting profiles at each end of the foam blank.

Once the deck is cut out trial fit it to the fuselage to check the fit.

Now we need to apply the decking skin to the foam deck. I use 1/16” soft balsa sheet for the rear decks and 1/8” soft balsa sheet for the mid and front decks, this is because the front of the Cessna is quite curvy so I will need to sand the 1/8” balsa to achieve a nice finish.

First apply two coats of white PVA glue to the foam decks allowing each coat to dry between coats.

Next sand the edges of your balsa sheets till they are nice and flat so that they can be joined.

Now lay your balsa sheet flat on your board and but them together holding in place with tape (I find brown packing tape works best)

Now turn the sheets over and place something underneath the balsa sheets so that they form a small V where they but together, now run some white PVA glue all along the V.

Lay the balsa sheets flat and scrape off the excess glue and leave to dry.

[Richie Carey Maddog Designs UK]

Once the balsa sheet have dried it can be glued to the decking’s. I use spray on carpet adhesive from B&Q.

Warning, this adhesive is solvent based so you can’t spray it directly on to the foam, this is why the two coats of white PVA were applied to the decks earlier.

The two photos below show the deference between applying the adhesive with and without the protective PVA glue. The first one show’s how the adhesive instantly eats in to the foam and the second shows how the two coats of PVA glue protect the foam and prevents the adhesive from eating in to it. You can get some none solvent based adhesive but I find that they just don’t have the same instant bonding qualities as the solvent based stuff.

First spray a coat of adhesive on to the deck.

Followed by a coat on the balsa, now leave until dry but still tacky.

Place the foam deck centrally on to the balsa sheet and roll until they bond together.

Trim off the excess balsa.

Place the deck back in to the foam blank and sand the ends and base flat.

Finally glue balsa sheet at each end of the deck to cap it off.

Here are the finished decks ready to be glued to the fuselage.

[Tony Bennett]

you make it look so simple sir.

i am learning lots from this thread. keep it up.

[Richie Carey Maddog Designs UK]

It is simple sir, if I can do it anyone can.

How’s the Fairey Fulmar coming along? Your little cartoon model has reignited something inside me for this old war bird, because I’m thinking more seriously about building a nice big scale one, though I will first, have to re-join the LMA and beg for my place back at our local LMA club Longhorsley, up here in Northumberland.

Then I will need to find a full-size to go visit, I think they have one in the Imperial War Museum Duxford, if not I might have to go for the firefly because they have one of those at Hendon. Some more research to be done on this one I think.

Richie

[Colin Leighfield]

Richie, the Fulmar is in the Fleet Air Arm museum in Yeovilton. It's even more interesting because it's the original prototype. It was retained by Fairey and did a load of development work, it's to full production standard.

If you're looking for something else interesting while you're down there, among other things they've got one of the original Westland Wyvern TF1s fitted with the massive Rolls Royce Eagle 24 cylinder piston engines, 3,500 hp. It looks quite different to the production versions with the Armstrong Siddeley Python turbo-prop and is effectively brand new, because it was never flown.

Too many things to do.

[Richie Carey Maddog Designs UK]

Thanks Colin, if there is a Fulmar at Fleet Air Arm museum in Yeovilton, a Fulmar it is then, and you are right there is so much to choose from. Personally my two favourite aircraft are the FW190 A8 and the Hawker Typhoon Mk 1 but they along with most other fighters of WW2 have all been done to death, and I have already done them both so I’m looking for something quite different, something you don’t see everyday and as this will be my first real project in over 18 years so it has to be something special and I feel the Fulmar offers exactly that.

Thanks again, you have saved me some time trolling the internet to find a full size to base my model on. Just some decent three view to find that I can scan in to my drawing software, I have some three views but at 1/72 they are not good enough for what I intend to do.

Richie

[Colin Leighfield]

Good stuff Richie. A day at Yeoviltown is a great thing to do, you'll be amazed at what's there these days. You can get close up to the Fulmar as well, I've got a couple of pictures. Aerodynamically it's perfect for a model, a guaranteed flyer, I reckon. It was derived by Fairey from a small light bomber prototype designed by Marcel Lobelle as a follow on to the Battle.

[Tony Bennett]

he he he

my fulmar is ready to be built.

just need some more wood and to finish the defiant first.

back to the cessna.

that is looking fantastic.

[Richie Carey Maddog Designs UK]

Apologies for not posting on here for a while but I have had some problems with my old PC’s, I had two of them die on me last week, it was totally my own fault as I had installed one design software package too many resulting in total shutdown due to lack of memory. I have now binned the old ones and replaced them with bigger and better PC’s so the problem has now been resolved, I’m just in the process of installing all of the necessary software, so normal post will resume shortly.

Richie

[Tony F]

Looking forward to you starting again Richie...and to help you in your new project you might want to check these out ?

**LINK** and **LINK**

Tony

[Richie Carey Maddog Designs UK]

Thanks for the links sir, I have just ordered both of them to add to the ones I already have, one can never have to many reference book can one, I just need to find a good set of three view scale drawings with details of the undercarriage angles, and that folding wing (which I am really looking forward to tackle) etc then I can start designing my model.

Richie

[Tony Bennett]

ooooooooooooooooo. sounds interesting.

[Tony F]

Any good ? = **LINK**

Tony

[Richie Carey Maddog Designs UK]

Thanks Tony, I already have a set of three views of the Fulmar which I could use to design the models airframe but they don't show any detail of how the undercarriage retracts or how the wing folds back.

I think a few begging letters or e-mails sent to the right people could be in order, you never know, if the gods are on my side I might be able to get my hands on some copies of the original blueprints, fingers crossed.

there's a saying up here in the frozen north ' shy bairns get nowt ' which means, if you don't ask something you will never get it.

Richie

[Tony F]

Nice saying up north Richie down sarf they say "gizus a cessna" lol looking forward to the Fulmar build mate !!!

Tony

[Richie Carey Maddog Designs UK]

Here we go again, on with the foam wings, for those of you who have never made foam wings, I think I should say at this stage that the Cessna wing is probably not the best choice of wing to use for your first attempt, this is due to the wing shape and the fact that it has to be made out of four panels.

Anyway start by cutting the required root, centre and tip templates out of 3mm birch-ply, you will need 8 in total. Now mark and cut out the wing blanks to the required shape.

Top tip, once you have all of your templates cut out, run some ZAP thin along the cutting edge, allow it to dry then sand with 1200 grade wet and dry (used dry) do this three times, this will help you achieve a super smooth cut.

Now mark the position where the rib templates are to be attached to the wing blanks.

Draw a centre line at each end on each of the templates, the vertical line in the photo indicates how much of the template you have to leave hanging over the edge of the foam block. This is the run in for the hot wire.

Now stick and pin the wing templates to the foam cores, stick the top templates on first then the bottom ones which are a mirror image of the top ones, this will ensure that you make left and right wing panels.

[Richie Carey Maddog Designs UK]

Set up your block so that you will be cutting at a comfortable height, use a couple of clamps and double sided tape and a suitable weight on top to stop the block sliding forward when you are cutting.

Always start cutting from the rear pulling the hot wire towards you, let the wire cut at its own pace don’t be tempted to force it to cut too fast or the ends of the hot wire will finish

cutting before the centre which will cause a dip in the leading edge of the wing.

Cut the top of the template first then the underside. Then turn the panel over and cut out the other one

Now you should have two identical centre panels.

Repeat for the outer panels.

You should now have the four panels that will make up the classic shape of the Cessna wing.

[Richie Carey Maddog Designs UK]

hahaha Tony I have just read your last post, I'll make you a deal, you find me some copies of the blueprints for the Fulmar Mk1 and I'll give you a Cessna as soon as I have a kit ready

[Colin Leighfield]

I have the foam, I have the cutting bow and the battery. All I need is the courage to try!

[Richie Carey Maddog Designs UK]

Go for it Colin, it really is easier than it looks, just do a couple of small test cuts first and if you are using ply templates, make sure you treat your rib templates with ZAP thin to prevent the hot wire snagging.

[Colin Leighfield]

I'll get there Richie!

[Richie Carey Maddog Designs UK]

[Richie Carey Maddog Designs UK]

next you will need to bore some servo extension lead holes through the foam, to do this lay the inner panels flat on your board, next place some packing on your board so that the top of the packing is level with the bottom of the cutting hole on the rib template (sorry I should have mentioned earlier in the thread that you will need to drill these holes in to the rib templates) next use double sided tape to stick a straight edge on to the foam core, this is to guide your cutting tool through the foam.

using a length of brass tube sharpened at one end bore through the foam, ensuring that you tool is flat against the packing and running straight along your straight edge..

only cut a small amount at a time, removing the tool from the foam panel after each cut and cleaning out the excess foam with a length of wood. I find it easier to mark the tool so that you know when you have cut halfway through the foam, then turn the foam panel around and continue the cut from the other side until the holes meet in the middle.

there you go a perfect hole for running your servo extension leads through.

do the same for the outer panel but this time you only need to cut to the position where your servo box will be positioned. once the holes are cut you can remove the rib templates.

now you need to glue the inner and outer panels together, start by laying some packing tape on to your bench, this is to stop the panels sticking to the bench during gluing.

glue the outer and inner panels together using laminating epoxy (slow setting, because this will soak into the foam creating a stronger bond) now wrap the entire joint with packing tape, this will stop the epoxy running out of the joint and form a nice smooth finish, now lay the two wing halves topside down and leave to cure over night. Next job will be to skin the two wing halves.