baz49exe

I've always wanted to build a four engined electric model and now I think I have the confidence to go for it after the 64" Wellington and 60" Hampden proved to me that two small out runners are perfectly capable of flying models of the that size so what size would four motors enable you to fly???
As with the previous builds the aim is to use very cheap 2" thick EPS wall insulation sheet for the build material with cheap spruce strip for all spars. Motors will be $6-00 HK outrunners !!
I looked at radial engined examples of four engined bombers as I have the cowl moulds and they are so easy to work with and I was seriously considering the Shorts Stirling but most of the nacelles on radial engined four motor bombers seem to be very short. Too short for me to fit my gear into anyway. Some even have the cowl sitting on the leading edge of the wing so not enough room there for my preferred set up.
Then I made a cowl for the Skystreak 26 / 36" build which proved to be close enough to a generic merlin engine cowl that I could mod it to represent the Lanc cowl without the chin rad which would not be possible to mould in one go anyway. The chin rad can be added later.( see attachments)
I decided to attempt to build the Lancaster in the end; due to the fact that the lovely long nacelles would, hopefully hold the motor, battery and ESC set up and would enable me to position the weighty components of the build well forward of the leading edge of the main wing and to cap it all I had a mould available for the engine nacelles...
I found an electric plan on Outerzone which was too small at 72"span; well the nacelles were and it was not much larger than the 64" span twin engined Wellington anyway.
To make the nacelles fit my cowl mould and battery requirements I scaled it up to 84" span and here is the resulting wing plan.(see attachments)
Now I had the wing (at least a full sized plan of it anyway) in my hands so to speak, I compared the nacelle to wing span ratio on the plan with a drawing of the Lancaster.
As you can guess the nacelles on the plan were too small and they actually need to be slightly larger which is great as the bigger the better for that area of the plan as far as I'm concerned.
Today I can make the main spar up as I have already bought the 12mm by 4mm spruce strip for the huge cost of £1-40 something.
It's a three piece construction with the flat wing centre section being one piece and the two out board sections the remaining two pieces.
I'll make up four plywood plates cut at the angle of the outboard wing sections and then use them to glue and clamp the whole spar together with the correct outboard angles set into place. The spar can then be used to correctly set the angles of the foam wing panels when they are eventually glued into place.
Next I need to find some 2" thick EPS foam sheet from the builders merchants which comes in 8ft by 4ft sheets so I'd better take a knife with me or I'll never get it into the car.
Somehow I have a feeling that this is going to be a very long build and it might not work but it is worth having a go at to see if a 7ft span four engined model can be built cheaply and lightly enough to fly on four $6-00 motors.

riverrat

Subscribed

baz49exe

Hi Jimmy, Happy New Year!!
I've moved along today as I marked out the three wing sections onto the 12mm by 4mm spruce spar and then cut the spar into the three required pieces.
I found a front projection drawing of a Lancaster from which to take the outer wing panel dihedral angle and cut the four ply plates to the correct angle. It's actually quite an angle.
I've found it easier to set the spar and angle plates together correctly if I cyano the plate on one side of the join while clamping the join between pliers and then add the other side plate with an epoxy resin bond. That way the correct angle is quickly set and it won't change while the epoxy sets hard.
That's the spar out of the way apart from carving the tip taper onto it . I think I'll keep a full depth spar until after the outer motor nacelle and then taper to the tip.
Need to get hold of some foam now for the wing cores.

pmullen503

Subbed!

solentlife

Bet you finish yours before I do mine !

I'm flying of on assignment again Monday - so will be away for 2 - 3 weeks.

I had planned on making the dihedral breal at outer nacelles for ease of construction but then realised the break is at inner nacelle ... b****y designers !!

Anyway my alloy spars / MDF / pine will see to that ok.

Cheers
Nigel

earthsciteach

baz49exe

No race Nigel, I'm going to take my time over this.
As I see it this needs to be as light as I can make it so it's a one piece wing for me. I think that'll make the wiring so much easier to do as well.

Have a good trip.
Barry

Bill G

You're really going up to a good size on this one. When I build planes over 40", I end up smacking all the models hanging in the build room above the table.
Building up to 53", I've been able to use the same methods and thin sheeting that I use on smaller planes, but at 84" it would probably take some rethinking, as well as not being able to predict the AUW and choose the power system off top of head. Looks like a good project.

solentlife

I'd love to do a 84" job .... but its not practical for me.

The motors I'm using are the HK Donkey motors ...

http://www.hobbyking.com/hobbyking/s...dProduct=15191

More than enough power ...

Nigel

baz49exe

Hi Bill, it is far larger than I've tried before and I'm rather concerned about hanger rash as well not to mention storage. Your comments on smacking models in the build room really resonates with me too as I'm always doing that as well.
I feel that I just have to try this and then I can really assess all the issues that arise from building and flying this sized model.

Voyager2lcats

Barry, as always you will build the "cheapskate's" foamie Lancaster- and I mean that in a good way. You lead the way with your scratch foam builds: afforadability, ease of materials access, and simple methods that require few specialized (if any) tools. What's not to like?

Bob

solentlife

It always annoys me when all is nice ... then smack ! Dented is the worst as a break can be reglued ...

Nigel

baz49exe

Proud to be a " cheapskate", but believe me Bob my desire to build as cheaply as possible is driven by necessity.
Retired, on a fixed income ( cue background violins) means that I have very little disposable income to devote ( or waste as my better half might put it) on models.
If I can show very little expenditure I can justify my pursuits in terms of money. Now time, well that's a very different matter.
I have to confess that I also get a huge kick out of building something for nothing or as near to nothing as I can get.

solentlife

Maybe it's time to start a 'Cheapskates Club' ?

I'm worlds repository for others crashed models ...

I hoard all the bits and bobs from models / gear ...

Even to foam and balsa I cut away from parts ... all goes in the 'later' bag.

Couple of days ago - was given 4mm Plywood ... had been sitting in a guys garage for over 30yrs ... I'm game !!

Nigel

baz49exe

Good idea Nigel. I don't get given crashed models, yet I do know how easily they can often be repaired and put back into the air again.
To discuss and disseminate basic building methods which work well with easily and cheaply obtained materials would be great.

solentlife

I now have a bunch of my own to repair after todays session ... just one of those days when NOTHING goes right !!

Cost :

Cessna 182 - tail broke by falling dog-guard in car
ME109 - not enough power and rolled in smashing fuselage.
HK 540 Edge Racer - hot landing and ended up hitting my mates wheel on his car ... motor firewall sheared of, wings popped out of snap-clips.
Ultimate Biplane - this is the one I rebuilt a whilre back and wrote a thread about ... I was inverted and decided to do a Tuck and Under inverted loop out of inverted TOO LOW ! Both wings smashed, lower fuselage nose broken up., motor mount broken.

I'm away tomorrow for few weeks ...... so will have them to look forward to ... except the Edge and Cessna which were easily repaired.

All this added to my Lancaster project ... and the rebuild of Multiplex EDF ...

Nigel

xuzme720

All I did today was break a prop. I guess I need to fly harder!

baz49exe

That was an awful day Nigel!
The tail broken in the car strikes home as I knocked the fin off my Spitfire once getting it out of the car at the flying site. Ruined my flying day.
If I break a model I get really annoyed with myself mainly because I don't really want to be repairing --- I want to be building something new.
Still as others have mentioned you can always look at a repair job as an opportunity to "refine and improve" the model .
On the subject of " building something new" I spent yesterday taping all the remaining plan sheets together to give a fuselage top and side view and to produce the fuselage and wing rib former patterns.
I re-drew the nacelle patterns and enlarged them to be closer to actual scale and now I need to make a trip to the city to get hold of the EPS foam sheet.
The size of the nacelles is concerning as they are as big as the fuselage on some of my past efforts.

baz49exe

Having got the foam board 8ft by 4ft square which I had to slice into three in the store car park to get it into my car, I decided to press on with the wing cores.
Luckily the centre section is constant cord so I drew out one airfoil profile and copied it twice onto cardboard. ( pic 1)
The cardboard worked well as a cutting template with the skystreak but this is larger so I hot glued two plant support sticks to the centre line of the templates.
Hopefully these would serve to purposes, to provide a wire hanging cutting starting point and to stiffen the cardboard lengthwise.
They were pinned to the edges of the blank and hot wired.
It worked.
I got my usual over heating lines which I think are caused by denser granules in the foam holding up the wire and me trying to pull it through single handed .
Any way it's fine, perfectly useable and a touch with sandpaper and spackle with sort the surface out.(pic2)
These cardboard templates save loads of time.

baz49exe

Got the centre panel gorilla glued to the spar now and the two outer panels hot wired and ready to be attached to the wing assembly.
Actually it's not Gorilla glue but a generic and identical glue which I found at our local tool supply store. It's far cheaper than the original with 760ml only being 3 times the price of 60ml of gorilla.
I used a heated blade to cut the spar slot but in truth I don't think it was worth the trouble and I could have cut it with a sharp blade far easier.

TLyttle

Seems I throw NOTHING out... I found an old plan (1947) for a small rubber model, and, on a whim, I built it. The original prop was 'orrible, so I used a 5" plastic one (Guillows?), and went looking for suitable wheels....... and found the orginals from the kit, 1/2" pine. Am I weird, or what?

baz49exe

I know where you're coming from "T" as I'm the same. I hate to throw things out as I know that two weeks after I do I'll find a use for it.
That just seems to be the way it works for me.

Build wise the wing panels are now completely joined so the easy bits are left. Just the aileron bays to cut out and aileron mounting spars to add.
The fuselage and nacelles come after. Not so easy

baz49exe

Cut out the aileron bays today, (avoiding the wing tips as they're not there yet and they will be angled to provide washout across the wing) extending them inboard to run behind the outer motor prop wash.
The balsa sub spars were cut from sheet and glued into place held by and reinforced with cocktail sticks pushed through the face of the spar and into the foam.

cyclops2

Do not sand in dry winter weather.

The 4 engined sea plane has 4...400 brush motors & 1 big ESC .........6 cell 2200 NICAD pack.

baz49exe

Hi Cyclops, what's dry winter weather? Seems all we get is rain
Your seaplane build looks great, unusual shape to it. Is it based on a full sized example and scratch built?

Barry