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FW 190A &190D from the same basic model

Balsacraft as the basis

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Erfolg10/06/2014 16:03:32
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Recently I purchased a Balsacraft Kit from the classifieds on this forum.

On receiving the kit, I could not be but impressed, at the quality of the design and kit in general, being very comprehensive.

I have studied the kit for some time, asked around, again on the forum, with respect to others experiences with this kit. It is apparent that the kit was produced at a time of change. Brushless motors were not the norm for electric flight, nor were Lipos the preferred power source. Yet the kit is extensively produced by CNC routing, presumably laser cutting had not yet become the mainstream process that it is today. It is similar with respect to servos, a single central servo is identified for the ailerons, rather than two which has become pretty much standard. Non the less, their is extensive hardware package, apparently nothing much needed to complete a model.

With these types of issues in mind some changes will be made, hopefully to gain an advantage. With no disrespect to be original kits.

My intention from the off, was to build a 190D, as I prefer the model for a number of reasons, the kit was intially seen as the basis to do this. However, after examining the kit, I have modified my intention to one A version and a D.

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I have started today, rather tentatively today. I found that I had no 2mmm ply sheet, every other size but no 2mm. This meant that I needed to buy some. To get the necessary length it made sense to go to MS. The nearest that I felt confident in stocking what i want is Blackburn Model Supplies. Mail order being no good due to the high postal charges and the limit on lengths. For me a 38 miles trip, each way according to the sat nav.

Before going I decided to do a stock check, as I was certain i had no 3/32" balsa sheet that is also used, But I decided to do a stock check, of what i did have, to avoid future constraints. I am glad I did as things were not as I expected. It turned out i have 14 off, 3/32" sheet, a similar number for 1/8, 1/4 and 3/16", a few sheets of 3/8" and so on. What I did not expect to find was, having just one 1/16" sheet and 2 off 1/32".

So I took a leisurely drive to Blackburn, in glorious sunshine and there purchased 1 off 48" sheet of 2mm ply and 20 off 1/16" balsa sheet.

Back at home I have started the marking out process for the "D".

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Eamonn Fahey10/06/2014 16:23:14
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Nice one Erfolg. That sounds like my balsa box and also my covering film. The problem is that I usually buy more before checking. surprise

Erfolg10/06/2014 19:55:22
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Already I could benefit from the collective knowledge of our community.

My problem revolves around the detail design of the model. To some extent I can see the logic of why ARTFs and this Balsacraft model use of a plywood box core, with most material removed, then formers attached to box, all located by interlocking pegs/extensions into slots. The whole lot then sheaved with a balsa shell. As the box is largely self jigging.

For the "D" it is not so easy to remove all the holes that the detail design has, to leave a minimalist frame/skeleton. The other aspect at the back of my mind, is that I normally use a technique, that certainly PM and I think TH use, and that is a ply doubler straight onto the shell. In my case I tend to use Evo-Stick, so that I can roll the ply on, producing a contoured side. More importantly, the ply is left as a plate, the back end tapered, so to provide a transition to the balsa only side piece.

I am tempted to leave the box section components as plain items. Looking at the plan, there appears to be an abrupt transition from the box arrangement to the back end balsa monocoupe.

If I was to carry out my proposal, in leaving the pieces intact, i am worried about weight build up. Yet it is essentially in the right place, at the front. In my opinion this would be better still on the "A" version, which appears to need lead in the nose (from Leccyflyer).

What do people think about the pros and cons, your personal experiences. Particularly, If I am correct, with respect to the sudden change in structure on the 190A. that is a lack of transition.

Edited By Erfolg on 10/06/2014 19:57:08

Edited By Erfolg on 10/06/2014 19:59:23

Erfolg11/06/2014 20:18:32
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After a rather troubled night, I cane to the conclusion, that the methods that Balsacraft had used for locating the separate items, that is tabs and slots, was inappropriate for a DIY home builder. Were as Balsacrafts components are produced with great accuracy, using a CNC router. In my case using a Stanley knife and a moterly selection of hand tools, I would not achieve the accuracy, in addition would be time consuming.

My solution is to miss out the tabs. Location would be achieved by sticking on short pieces of balsa strip, to help location, then complete the joint in the same manner recommended by Balsacraft, that is using cyno.

I keep turning over in my mind the solution of Chris Bott, for access to place and arm the Lipo. With the FW 190, the engine cowl causes a bit of a problem, plus the round cross section at the front, seems to make this more problematic. Then I have been wondering, did his Spitfire start of with the complex internal structure of the FW 190, being divided into two compartment?

I have cut out the two sides, yet remain undecided to the extent of the lightening that sensibly should or could be done. As the weight issues normally seem to be confined to the rear. In many cases lead may be needed at the front to achieve the desired CG.

So at present I am very undecided!

Edited By Erfolg on 11/06/2014 20:19:01

Erfolg12/06/2014 11:53:39
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Speak to me!!!!!!!!!!!!!!!!!

I have hit my first significant problem.

Today i removed the first parts from the kit, with intention of assembling. The differences becoming apparent between then and now. The area identified for the Nicad a 7 cell Nicad, will at first sight take a Lipo. However on looking more carefully with the kit parts to hand, a whole series of Bulkheads, have apertures far to small for a 3s Lipo.

The central area, which has bags of space for a Lipo, is totally isolated from any access.

Input as to how others have dealt with this issue would be appreciated, to enable me to implement a acceptable solution.

Now off into the garden to pick Gooseberries, whilst await at least one response, four or five would be better!smiley

john stones 112/06/2014 12:43:57
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190 A has the short nose ERF, so makes a hatch tricky. I would be looking at a removable canopy on both versions. It will involve some clever thinking and building whichever way you go, so I would aim at what would be the most user friendly solution

John

Erfolg12/06/2014 15:07:14
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I have now encountered my second issue.

As I have written i am using 2mm birch ply purchased from Blackburn Model supplies. The finish on this ply is far superior to that of the Balsacraft kit. Yet I have discovered a major issue, it weighs considerably more than the kit material.

Whilst i had been intending to leave the side pieces as plain surfaces, unlike the kit side pieces. It is apparent that I will have to remove the windows/apertures as the original kit. Even then I am anticipating a significant difference in weight, being much heavier.

I will have to think carefully about much of the structure. The front not being to much of an issue, as weight apparently is necessary to get the CG where it needs to be.

Any way, it is back to my Dremel fret saw now, for some noisy sawing.

Erfolg12/06/2014 15:34:37
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Well, I may put the whole project on hold, whilst I do a rethink.

The whole font assembly as assembled from the Balsacraft kit, comprising, 2 off side pieces, 4 off bulkheads and 2 off top and bottom plate weighs in at 24g.

My two side pieces alone, fretted out come in at 64g.

nearly 3 times the weight. I cannot clearly just replicate the whole of the Balsa craft items, not without sourcing some light weight 2mm ply.

Dam and dam again. I really do need ideas.

Erfolg13/06/2014 11:22:49
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Yet another troubled night or probably early morning.

I checked the availability of Light ply from Blackburn Model Supplies(BMS). It seems that their thinnest grade is 2.5mm, which is 25% thicker or more. As the Balsacraft kit is slightly < 2mm. It is not unreasonable to assume that it will be 25% heavier.

It may seem it does not matter at first sight, examination of the Balsacraft assembly is both light, and rigid. The Blackburn Model Supplies (std) ply is far superior in quality, being 5 ply against 3 ply. The finish is superb, it is very high strength, at the cost of weight.

This means i am rethinking extensively how I will be doing my "D" build. 1/16 ply will be substituted for some items, maybe, although this lacks rigidity unless backed with balsa. Many of the formers will become balsa. Although, on my way home on Monday, I will pick up some lite ply from BMS.

In the mean time I will continue to agonise over the best way of doing the alternative build.

I do have to keep reminding myself, that the kit is apparently tail heavy, needing lead in the nose. Hopefully with a longer nose the "D" will come out well balanced, not needing lead.

Edited By Erfolg on 13/06/2014 11:24:18

leccyflyer13/06/2014 16:54:17
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Have you though of using Blackburn Models rather excellent balsa ply? It's lovely stuff and may be even lighter than the liteply.

Erfolg14/06/2014 11:15:03
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Leccyflyer

I hope to pick some"Lite Ply" up on Monday, as mentioned previously. Is this the same as Balsa Ply you mention?

I have been thinking during the night about the weight problem, and had come to a sort of conclusion. that I would use some thin ply with a balsa facing, to try and get the benefit of some unidirectional strength of the ply, and the stiffness of the balsa, combined with the glueing area that the combined edge provides, without a massive build up of weight.

I have also concluded that rather try and replicate the balsa craft structure in the "D", I will treat the build more in line with a traditional build.

If I had fully resolved the design differences between the Balsa craft "A" and the "D" I am making, I would have drawn out the new side pieces and location for bulkheads etc, and enquired with Lasercarft in Cumbria in knocking out a set of lite ply components. However I was reluctant to spend the time in doing so, particularly as I recognised I did not fully grasp all the nuisances of the drawing and components.

I also discovered that although my scanner, prints out 1:1 copies of the components. Scanning to the CAD program as a bit map was not exactly 1:1, so I was using the shapes as a basis, whilst inputting exact vector co-ordinates. This was taking some time and I do not want to be a CAD operative, rather a model builder and flyer.

leccyflyer14/06/2014 12:22:51
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The Blackburn Models balsa ply is quite different than liteply. Balsa Ply is made up of laminations of proper pukka balsa wood, with the grain direction of the plys at right angles to each other. Lite ply, so far as I understand it is made up of laminations of some other, unearthly timber, imparting those well known qualities of instant warpage when you look at it sideways for a few seconds.

If you haven't seen the balsa ply, ask them to show you a bit -it's marvellousstuff.

As regards fitting lipos in the battery box of the Balsacraft FW190, my Tipple 3s1p 3000mah packs slide right in, no problem, as do my nice new, as yet unused 3s1p 4200mah Gliders packs. What size of lipos are you struggling to make fit?

Erfolg14/06/2014 15:20:58
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I have been trying a standard, that is Turnigy 2200 3s in the Balsacraft skeleton. It is a tight fit, particularly in that i put a polystyrene protector in the front.

I am surprised at the sizes you are using. Does it help with the CG? elevating the lead issue that has been mentioned.

It is exactly this type of info from those who have passed this way before that is invaluable to people like me, not certain, wondering what really matters, what solutions that have been tried, what can be left well alone.

It is a little surprising that Balsacarft or is it SLEC, have not considered a "D" version themselves, as the work required to produce a second model in the kit range is so small compared to a new model.

leccyflyer14/06/2014 17:30:37
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I only really use 2200 3s1p lipos on my smaller models - things like the Parkzone Spitfire for instance. For the funfighter sized models which were originally running AXI2820/10 or Mega 22/30-3 motors I've always used at least a 3000mah 3s1p pack. I suppose it does help a bit with the balance, but the packs are just physically the right size and shape to be a direct drop in replacement for an 8 cell Sub-C Nicd pack. Those are the packs that I've used in two Ripmax Spitfires, which are about the same size as the Balsacraft kits, and rumoured tbe based on the Balsacrat Spitfire. I'll maybe put a few pictures of the battery in place in the FW-190 once it stops raining, if that will help.

It's a shame, but SLEC haven't made these models for years and there are frequently repeated rumours that someone is going to do so at some stage. However, so far, these have never come to fruition. IIRC Cambria used to do the Dora as one of their funfighter range, whilst Cambrian did the Bf109 instead.

leccyflyer14/06/2014 17:55:44
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Here's an old picture of the space available for the battery, which slides in between the two plates to the right of the picture..

fw190internal1.jpg

A modelling pal did suggest the possibility of loading the battery from the front, through the cowl, but I concluded that there wasn;t enough room, as shown here.

fw190front.jpg

Looking back at those pictures another modeller (John French) did succeed in fitting a battery access hatch to the BC FW-190 by putting his smaller 2s2p 2100mah lipo in vertically behind the firewall, with a 1/64th battery hatch in the top of the fuselage. that was a solution that i didn't pursue, following the epiphany suggested by someone else to just think of the wind as a big hatch..... There are other pictures on that 2010 thread that I started on RCG, but I'm not certain about RCM&E's policy on linking to threads on other sites.

Erfolg23/06/2014 19:56:35
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I have made some progress.

I have started on the front framework. The Balsacraft version weights is at 80g, my slightly longer version weights in at a porky 140g. I think the main difference is the real ply side frames, then the 25% thicker lightply frames etc.

framework.jpg

I guess that it makes sense to start on the wings next, as access to the open framework appears to be advantageous to fix the front wing locating peg.

But if others know better, I am all ears.

Erfolg01/07/2014 20:07:08
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I have made more progress with the body although at present not much to show.

I am turning my attention to the wings now. this is another area which is very different to how I normally build a wing. I will certainly build one model as per plan. I am less convinced for the second.

My concerns, or maybe that should be differences is that I usually make my ribs from balsa sheet, not 2mm light ply. The second difference, is normally use spruce spars, with a shear web. Whereas the Balsa craft uses 2mm balsa web as spar and shear web. My method has a lot more work with respect to the spar arrangement, but is it over engineered? Then I would prefer to use 1/8 balsa wing ribs, rather than light ply, mainly because I fear that the light ply will be relatively brittle when compared to balsa, the weight is probably about the same.

Any views and or experiences with the Balsacraft method?

Erfolg04/07/2014 14:31:41
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I have made some progress. In the main preparing for the next stages.

partkit.jpg

As can be seen I have assembled two sets of lower skins. I have also made two sets of sides for the body a 190A and a 190D.

I will now start on the wings for the 190A, then move onto the D.

I know I am slow, I always am, yet with Football, Tennis and motor racing, there is no time for anything. If it was not raining, I would be now out at the field. crying 2

Erfolg08/07/2014 16:22:02
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Just in case anybody thinks i have stopped due to the various disasters in the world and so much we have taken for granted is now under threat, I thought a note of reassurance is what is needed.

I know many like me have been shocked, driven to the point of despair, at the England Team failing in the preliminaries of the World Cup. Then Andy Murray, and his shock defeat, at least to me. Quickly followed by our Cav, crashing and suffering major injury. Through all this I can reassure all, I gritted my teeth and kept going.

My one hope is, I do not really knowcrying 2

So here is the latest picture.

skelwing.jpg

As can be seen it is essentially identical to the plan/kit. That is other than I have created cut outs for 9g servos.

Part of my time has been taken up with creating a set of wing ribs for the second wing,

With respect to the second wing, I will be looking through my spruce spar collection, to see if I can find 4 small section spars, as I do have doubts with respect a plate spar, which relies a lot on the wing skins for section strength. This is because my models receive some rough treatment, not all landings are perfect, even if they are, have to either contend with a very much undulating field, or the alternative venue, being rough pasture.

Edited By Erfolg on 08/07/2014 16:24:02

Erfolg22/07/2014 16:49:33
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I continue to plod onwards.

twowings.jpg

I have now essentially two wings, about 90% complete.

I will now return to the bodies, starting with the 190 A, as that is the kit. Also i am finding it is a little tricky working out quite how the body is assembled. You certainly need to read the instructions, in conjunction with the drawing to sort out what goes where, when and how.

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