Build Log 1/9th Scale Nijhuis Lancaster

[pantuner]

I've been the fan of the Lancaster for about as long as I can remember the concept of an aeroplane back when I was a kid in South Africa. I remember watching a grainy, black and white movie called "The Dambusters" on TV when I was about 7

When I found out (long after it was news) that Tony Nijhuis was offering kits, I bought the CNC pack, canopies, and plans. I've been somewhat remiss in not starting this thread a few months ago (got the kit in September 08), and have been soundly spanked by a few friends for not doing so. The first few posts will play catch up, as I have taken some pics along the way, after that it'll be anybody's guess as to how motivated I stay and how much time I have.

My first impressions when the boxes arrived in their dribs and drabs were that the plans looked really good, canopies even better, and the CNC pack was superb. Great job Tony!

My next impression was where in the bloody hell was I going to build it? Its HUGE. I was kind of relieved I hadn't succumbed to temptation and bought the 1/6th scale kit with its 17ft wingspan.

Living in a two bedroom apartment with my wife (Angel) in Denver, Colorado, we don't have a ton of extra space. Any extra space we *did* have when we moved in just over a year ago has looong been taken up by whatever other planes I could cram in there

But we rearranged the office/2nd bedroom, purchased a door to use as a work table and a few shelves to lay it on, and off I went.

At the time of starting this thread, I have most of the fuselage sheeted, I have the horizontal stab and rudders mostly done, and I have framed up but not sheeted the wings. I've posted (hopefully - it may be a few posts before I get the hang of this) some pictures showing this in at least a rudimentary way.

There are a few other details I've changed/tweaked to be the way I like them, and I'll describe these in future posts.

[paulbw]

Hi Pantuner,
I will declare an interest in your project as I too have the plans, cnc kit, glazing, etc for this TN designed Lancaster. Unlike you, I have yet to make a start but I hope too soon. Great film isn't it? Tell us more about your wheels/power/props/spinners, etc.
Paul W. (...rad shutters auto..!)

[jhspring]

Wow! Now that's a challenge. 'Nuther Lanc fan and wannabe builder here, love to see more details and pics. Please thank your friends for the spanking on my behalf.

Cheers,
Jeff

[mtflyr]

Looks pretty cool.

Pete

[fockewulf37]

What are you planning on powering it with??

Ty

[pantuner]

I haven't decided on a power source yet, other than Lipo's for sure. I will most likely buy the cells unwired from www.lazertoyz.com, and solder them up myself.

The thing I'm facing on the power side is this - the suggested motor/prop combo is for a 12" prop, but that's too small for scale. A scale prop would be closer to 15", and would really be three bladed. I know that Varioprop make a threeblade in this size, and I would be able to tweak the pitch as required. Of course, pitch balancing 4 props might be a fun task...lol. I haven't got as far as getting any of that gear yet.

As far as wheels go, my calcs show that a scale wheel for this would be around 7", which is bigger than the recommended 6" - 6 1/2" wheel on the plan. I don't have a source for these here in the USA yet, I am considering making my own.

The retracts....well....again, I'm considering doing my own thing, I really want to make something very scale and have the wheel-bay doors open and close like the real thing. Shouldn't be difficult, just time consuming.

[eye4wings]

That will be absolutely magnificent!

Have you come across the Vortex range of motors? They do a whole range so you could take your pick - and they are cheaper than AXi!
I get mine from www.allelectricrc.co.uk

I would encourage you to go for the 15" three-blade if that is the scale size. You can use a lower stack of cells to keep the amps down.
We can really put one over on the IC boys who have to change their scale props before flying. We just start up and taxi out just like the full size.

And Kavan do some reasonably priced plastic wheels - I just bought a pair of 6". Not as pliable as rubber but half the price and half the weight of Dubro.

[pantuner]

I am not making the Dam Buster version, so I needed to design some bomb bay doors.

One of the cool things about the Lanc bomb bay doors is that they have that scalloped look inside (see the photo I took of the Canadian Warplane Heritage Lanc). I really wanted to recreate that look.

I should mention that in the plan, the underside of the model is just a flat "slab" with some rounded corners going to the sides of the fuselage. This is easy to build, but doesn't reflect the lovely pseudo-elliptical shape of the underside of real aircraft. I ended up reshaping all the supplied formers and building some new ones so that I could get that shape - more on that in a later post.

The first attempt I made for a set of bomb bay doors was a disaster; I have no experience at building or designing parts for a model this size, and it showed immediately - they warped, the sheeting looked like crap, and they just didn't seem to be worth finishing.

I spoke to some of the guys at our club about strategies for doing this a second time around, and they had some good ideas. So the next set of doors looked a lot better - see the photos in this post. The formers are all 1/8 balsa, and the sheeting is 1/16 on the outside and 1/32 on the inside. I essentially built both doors as a single unit which I cut in half down the center once it was nearly done. This worked pretty well as a construction technique, and it wasn't very difficult to make the cut to split them.

However, they still didn't have that "look" that I wanted to capture; part of this was due to the fact that I didn't have a complete photo anywhere of the entire length of the inside of a bomb-bay door, and so I was guessing a bit as to what the thing really looked like anyway. After a lot of digging on the net I found a photo on some Russian/Polish site with a complete look at the doors. This helped me tremendously, as I could get a fix on where the central spar meets the front and back of the door.

Having found this, and being in no mood to hand shape another set of formers, I set to with my CAD software and designed out a complete set of door formers. It would have been quicker to make them by hand I spent 4 evenings doing this, but at least now I have ability to reproduce pieces or tweak them from a known starting point.

I sent the file to my favourite laser cutting gurus (www.foxlite.com) in Dayton, Ohio. Literally 5 minutes ago they called me for credit card info for payment, and told me that the pieces have shipped. Pics of the third round of bay doors coming up when the bits get here.

[fuelsguy]

One great project, looks terrific. I thought a 1/18th scale would be big, but 1/9th is huge. I build all my fighters at 9th scale to just fit in my car.
I have a few photos of the Lanc in the Auckland Museum if that would help. you can PM me and I'll send them on.

Ivor

[Wilit run? 353]

wow great work. I have been pondering over whether to get the 72" or the 134" or the 17ft one they all are nice but I want a lanc that will stun the crowd so this one looks right. I will keep watch.

thanks
willit

[fockewulf37]

Well before you decide on what motors you are going to run I would really wait to see what your weight is going to be. I have build a Handley Page Halifax at 146" wing span. I build really light ,I believe. I was shooting for 40 lbs and bought motors for a 40 lbs model. Well as it turns out fully loaded and ready to fly it weighs 46 lbs. I am right at a 1000 watts of power (4000 watts total) and I am turning a 16x10 prop. That puts me at about 85 watts per pound... I have not flown it yet but hope to in the next week or so. I would really love 100+ watts per pound but I have too much invested to change right now...

Also I know you most likely have read this artical many times. It has made me feel more comfortable with the power that I have for the plane. He appears to have flown at 60 lbs plane with the same power that I am using...

http://www.largemodelassociation.com...jhuis_lanc.htm


Here is a pic of my Halifax in colors. I have since added the turrets and and other minor stuff.

Ty

[pantuner]

Hey Ty,

Cool looking model, I think you should be ok at the power-to-weight ratio you've come out at.

I have no doubt I am going to be a little over the suggested target weight, as I have a number of changes and additions, which all add weight. Another factor I am concerned about is that here in Denver we are at 5000 ft MSL. I have some small foamies that flew fine in Ohio at 500ft but simply will not ROG here in Denver, so I'm sure I will need to be on the high side of the power equation.

I am planning on adding flaps to the Lanc precisely for that reason - at least the landing speed should come down to something manageable.

Let us know how the maiden goes, make sure you have a video camera available!

Steve

[pantuner]

The pieces arrived from Foxlite today. As usual, the cutting is excellent, if you are looking for laser cutting folks, these guys are hard to beat.

It took a just a few minutes to pop the pieces out and to press fit them together. These pics are of the press-fit version, no glue!

What you're seeing is the bomb-bay door "upside down" as if the aircraft was inverted. There are some extra bits on each former to help in the alignment during construction, these will get cut off once the door frame is glued and the outside is sheeted.

[pantuner]

Listeners who recognise that gag, please keep their traps shut

I really want to animate the gun turrets on this model. My idea is to have the pilot use one radio to fly the plane, and have a copilot play with the turrets and other goodies like bomb-bays and bomb-release mechanisms. I really want the turrets to not only rotate, but also have the guns move up and down.

The top turret is obviously not much of a challenge to do, but the nose and rear turrets....

After hours of looking at the supplied plastic canopy, the plan, and what I had built, and comparing all of this to photo's of the real aircraft as well as some fairly comprehensive 3 views I had scrounged, I came to the conclusion that the front of the model was about 3/4" too short for scale. As designed, there is no way that I could make the front turret rotate more than about 5 degrees each way - the real thing moves 95 degrees each way.

Somewhat reluctantly, I cut the nose off, forward of F1 (front-most former on the fuselage, for those who don't have plans to refer to ). I made a mockup of the longer nose, and discovered to my delight that if I thinned out the inside of F1, I could easily make the canopy rotate, with the back corners of it sliding neatly into the fuselage as per the real deal.

The next problem was to find a hollow bearing mechanism that would provide the rotation base. I suppose I could have made the floor of the nose turret out of 3/16 balsa, and just made some kind of pivot point on that. That seemed far too simple

I spent some more time on TurboCAD, and got a file over to Foxlite again. Pieces cut, mailed back to me.

Now I have a piece designed as a nose former, which I will refer to as NF. The outline of this piece is essentially the same as a top-down view of the front of the model, forward of F1, but extended about 3/4". NF has a 4 inch diameter hole through it.

I then made a top and bottom ring. The outside of these rings had a diameter 3/8" bigger than ID of the hole in NF. The inside of these rings is 3/8" smaller than the hole in NF. There are 16 holes, each with a 1/16" ID, spaced evenly around the inside of each ring - refer to the photos.

The idea is to use a vertical 1/16" carbon rod running between matching holes on the top and bottom rings, and to then put a 1/8" OD nylon sleeve on each post. The nylon sleeve will run around the hole in NF, and voila! we have a working lightweight bearing with a large hole through the middle.

As it turned out, I really only needed 4 sets of holes, and not 16. As I assembled it, I tested it with 4 and it seemed to work just fine, and there was no incentive to cut more carbon and sleeves than necessary.

I've included a mock up of the new nose with rotating turret in the photos. Moving the turret will be done with a pull-pull system from a micro servo with a large control horn. The bearings rotate really freely, so there is hardly any load on this. I probably won't get the full 190 degree sweep of the original due to the mechanics of driving it with a servo, but I should be able to get about 160 degrees or so.

Now if only I can find a way to make hollow gun barrels and run compressed air through them, with some kind talcum powder feed to simulate smoke from rounds being fired...

[fuelsguy]

The model is coming at a fast pace.
Looking at your front turret, I think you need to extend the turret aft a little. It took me a long time to realize the front turret goes outside fuselage contour when swinging from side to side. I built a 72 inch Lanc and spent a lot of time doing what you are doing, trying to make the front turret stay in the fuselage contour. I finally saw a video clip with the turret moving and realized it swings out of contour. Maybe someone has better information on the turret design.
Hope this helps,

Ivor