84" EPS Lancaster Build

[cyclops2]

High Barry.


That was my first Scratch build. Took the AMA China Clipper plans to a blue print place & had 2 enlarged copies made. I made outside body templates of the frames. They really speeded up shaping the body.
I can actually toss it & have it glide 30'. I wound up stuffing the battery into a hollowed out nose. Then I still had to REALLY thin out the tail. Removed the push cables for R & E. Switched to pull- pull lines. BIG difference in getting the COG right.
Those 2200 NICADS would allow a 100' to 150' take off run & 1 circle back for a landing. The horizontial stabilizer is 2X larger than scale. But the plane is very stabile in a breeze.
4 engines ? Gets the hair to stand up.

The picture show the .8 oz motor / gearboxes I now use in planes. The 2 Guanli PBYs have them. Benifit is a HUGE battery is needed to get the COG right. A 1/2 hour flight is possible now.

Brushless geared costs big time compared to those old 400 brush motors.
My daughter said to spend the money !

Rich

[baz49exe]

Rich, that was a great start for a first scratch build
I'll bet you're really pleased that it worked out so well for you, I know I would be.
I've started the fuselage on the Lancaster now. It too uses formers to cut the foam. It's based on a threaded rod and former method with the foam sheet trapped between the formers under tension from the rod.
In the pics I have the two side blocks in place and I just need to add the top and bottom ones.
A quick hot wire around, break it down and glue the four pieces together and I have one section of fuselage.
Just got to do that a few times more .

Barry

[cyclops2]

I tried a homemade hotwire bow. Just never got those even cutting lines. So I built up a 4' long 33 grit sanding board & a 100 grit.

[Voyager2lcats]

Oh ho! I see you have started on the Lancaster fuselage in the basement! Are you still hot-wiring outside? I am looking forward to your pictures of the four nacelles. I don't think I will be doing this one, but it is fun to window shop! P.S. As always, your scratch builds rock.

Bob

[baz49exe]

I get those cutting lines as well Rich. I think it's mainly due to the poor quality granular foam I use. Doesn't worry me because at least it gives me the overall form and some minor sanding and spackling sorts out the rest.

[baz49exe]

Bob, it's cold and wet outside so I've sneaked down to the basement and resorted to setting the cutting rig up by the outside door with a pedestal fan blowing the fumes out through the opening.

[baz49exe]

The basic fuselage form is now 75% complete ( bit like the wing really) and after I add the final tail end to it I can get down to the spackle and silk finishing.
I'll silk and varnish the fuselage before I cut away the wing seat and the tail plane slot to strengthen the foam before cutting.

[solentlife]

Are you slotting your wing in from top or bottom of fuselage ?

On the plans I use - the amount of fuselage below wing is greater than above - so I'm going to slot in from top - leaving maximum fuselage sides to keep longitudinal strength. I'll probably add balsa sheet stiffening as well.

Nigel

[baz49exe]

Hi Nigel, good question and one I've wrestled with on all the bomber builds.
All the three models shown had the same issue but I figured that the pressure from the wing would always be trying to pull it off the fuselage if I top mounted it whereas when bottom mounted the wing would push itself into place.
I did make double plate and bolt mountings on the wing fuselage join to hold the joint together and prevent any flexing of the wing seat though.
The cut out was most extreme on the Hampden so I included a pine backbone across the upper fuselage to bridge the wing seat area.
I have had no problems with this set up on any of these models so I'm going to mount the Lanc wing from the bottom and include a pine backbone to bridge the wing seat area.
Sorting out these issues is part of the building fun isn't it?

[solentlife]

Now I have the bench table saw .. I thought about a pine backbone, cause I can cut to whatever gauge I like now ... maybe I'll look at that again ... but my wing cut-out is already set from top.

I have to admit that many items get sorted as I'm building and not always as per plan.

I'm looking to increase the amount of laminated foam parts I use to cut back on heavy stiffening ... use of epoxies etc.

The construction of the real planes also I think can teach us a few things ... with cross beams etc. between formers / ribs etc.

My foam cutting, hot wire, is not so good as it used to be !! But will try again to create top decks etc. for a few models i have planned ...

nigel

[pmullen503]

A deep vertical spine is a good idea. Make sure it extends fore and aft of the wing saddle a good distance.

Another thing that will help is to tie the sides of the wing saddle area together to form a box. It doesn't have to be heavy, you just want to stop the sides from spreading outward. A thin layer of epoxy soaked glass will do the job or thin balsa with the grain running side to side.

I like to use wing bolts fore and aft rather than a single bolt and pin to allow the wing itself to tie the fore and aft sections of the fuselage together.

[baz49exe]

Nigel, I wish I had a mini bench saw; would be very useful for me too.
The pine strip is very easy to strip to size with a knife though .
On the subject of plans, well nothing goes as per plan with my builds.
I like to build from 3 views if I can get decent ones with cross sections attached. If I have to use a plan it will be for outlines only and the foam construction details will have to be worked out as I go. That's the fun part!!
I've been experimenting with laminating 3mm depron recently as well. Mainly because it came free beneath a frozen pizza and I'd run out of 6mm sheet.
I used gorilla glue to laminate the sheets for a tail plane and I was surprised by the result. In structural terms the sum seems to be greater than the two parts.

[baz49exe]

Originally Posted by pmullen503

A deep vertical spine is a good idea. Make sure it extends fore and aft of the wing saddle a good distance.

Another thing that will help is to tie the sides of the wing saddle area together to form a box. It doesn't have to be heavy, you just want to stop the sides from spreading outward. A thin layer of epoxy soaked glass will do the job or thin balsa with the grain running side to side.

I like to use wing bolts fore and aft rather than a single bolt and pin to allow the wing itself to tie the fore and aft sections of the fuselage together.

Good to know that we are both thinking along the same lines.
I like the suggestion about boxing the saddle area as well. It needs to be light and provide access for the radio gear.
I'm thinking kebab stick tension bars fixed across the fuselage at the moment. They correct bulging building walls.

[pmullen503]

Originally Posted by baz49exe

Good to know that we are both thinking along the same lines.
I like the suggestion about boxing the saddle area as well. It needs to be light and provide access for the radio gear.
I'm thinking kebab stick tension bars fixed across the fuselage at the moment. They correct bulging building walls.

That would work too. Sink them deep into the foam sides to increase the gluing area. If this is ever going to be hand launched, put a former across the area where you would hold it. It's embarrassing to crush your fuselage when chucking it...don't ask me how I know.

[solentlife]

I've never used Gorilla Glue ... always been an Epoxy / PVA person ...

Recently started using Hot Glue more and more, basically for convenience.

The wing saddle ............ thoughts at present ... balsa sheet doubler ... pine spine running fore-aft .... laminated foam formers ....

Baz - the table saw allied to the bench jigsaw means any spar or strip I need is done deal. I now spend time in DIY shops checking out wood !

Nigel

[solentlife]

OK ... just clicked Buy it Now on a 8oz Gorilla Glue bottle ... 14 quid + 4 quid P&P to Latvia ...

Let's see what all the fuss is about !

Nigel

[baz49exe]

Originally Posted by pmullen503

That would work too. Sink them deep into the foam sides to increase the gluing area. If this is ever going to be hand launched, put a former across the area where you would hold it. It's embarrassing to crush your fuselage when chucking it...don't ask me how I know.

It'll have to be hand launched as I have a dislike of the wheels and grass combination.
All the mid wing models have a deep fuselage body beneath the wing which acts as a hand launch hold. At that point as the model lands onto it as well it's solid foam and with that and the silk covering it withstands hand pressure very well. I can easily see how you could put your hand through a hollow structure though. I'll bet you were annoyed.

[baz49exe]

Originally Posted by solentlife

OK ... just clicked Buy it Now on a 8oz Gorilla Glue bottle ... 14 quid + 4 quid P&P to Latvia ...

Let's see what all the fuss is about !

Nigel

I'd read glowing reports about Gorilla Glue on here and I thought I'd give it a go even though I couldn't see why I needed to change from my white resin wood glue.
The advantages became obvious the first time I used it to stick the thick EPS blocks together. It foams and expands so it fills all the hollows in the joint. You can do that to an extent with white glue however it shrinks as it dries so its bound to leave hollows and run out leaving voids as well.
This stuff just makes new foam. AMAZING!
It bonds so fast (5 - 10 minutes) that you can hold a tricky joint in position until it's set up correctly.
I don't worry about the over flow either as after an hour, before it's really hardened you can trim the excess off, flush with the surface, with a flexible snap off knife blade and the result is just like foam.
Great for mending a broken foam fuselage!
I've found a source of a generic brand in town which is a fraction of the price of Gorilla Glue as well.

[solentlife]

Originally Posted by baz49exe

I'd read glowing reports about Gorilla Glue on here and I thought I'd give it a go even though I couldn't see why I needed to change from my white resin wood glue.
The advantages became obvious the first time I used it to stick the thick EPS blocks together. It foams and expands so it fills all the hollows in the joint. You can do that to an extent with white glue however it shrinks as it dries so its bound to leave hollows and run out leaving voids as well.
This stuff just makes new foam. AMAZING!
It bonds so fast (5 - 10 minutes) that you can hold a tricky joint in position until it's set up correctly.
I don't worry about the over flow either as after an hour, before it's really hardened you can trim the excess off, flush with the surface, with a flexible snap off knife blade and the result is just like foam.
Great for mending a broken foam fuselage!
I've found a source of a generic brand in town which is a fraction of the price of Gorilla Glue as well.

It's one matter that I wish to 'cure' the ridge of unsandable glue left along joints etc.


Generic ? I see a couple of supposed alternatives on ebay - but am not sure whether same.

Will be looking out for another name when I get back to Latvia ...

Nigel

[pmullen503]

I use the white Gorilla glue almost exclusively with foam. Mist it with water to get it to foam up more and it will sand easier.

[solentlife]

White ? I read a few sites before deciding on the bottle ... all reckoned brown ... white being the less water resistant ?

Nigel

[pmullen503]

Originally Posted by solentlife

White ? I read a few sites before deciding on the bottle ... all reckoned brown ... white being the less water resistant ?

Nigel

White sets up faster and is lighter, easier to sand. Brown is good for laminating outdoor wood structures. Both work, I prefer white for foam especially if you have to sand a glue joint.

[baz49exe]

The glue I'm using is a brown coloured expanding foam carpenters glue which they use around here for boat repair as it loves salt water and apparently it will even set underwater!!
I haven't seen the white variety of Gorilla Glue in our neck of the woods but I can see how well it would go with white foam. Just as white spackle does I guess.
I finished the basic fuselage today all ready for a coat of silk and varnish tomorrow. It's 4ft 2in long without the nose section or turrets. It doesn't half look big to me but it's not that heavy at 11ozs.

[pmullen503]

The white version may not be available outside the US. Polyurethane glue needs water to cure, so it's important to not leave your bottle open or it will set up.

If you need to fill a large gap, you can activate it by pre-mixing in a small amount of water. I had a prop come off once and embed itself in the fuselage, punching a sizable hole. I taped over the hole on the outside, premixed the glue and water, then slathered it over the hole from the inside. The glue foamed up and made a perfect patch. I was back in the air in about 45 minutes.

[pattern14]

Another great project, but one puzzling aspect? If you had to cut the building materials to get the foam boards into the car, how do you plan to get the finished product in and out? Trying to visualise it strapped the roof, or you cutting off the top of your car to make it a convertible seems a little too enthusiastic. Then again, all you really need is an angle grinder....