2013 Mass Build - general chat thread

[WolstonFlyer]

Hi Mike

Sorry I didn't realise the CNC kit required laminating to build up the wing thickness.

I am still not sure I would use contact adhesive but then again I have never needed to join wood like that ....

anybody else got any thoughts?

[Colin Leighfield]

I bought the CNC set and additional wood pack and didn't have to laminate the wing panels, they were cut from 3/8" balsa. I don't think that this is a good idea, however you do it. Whatever adhesive you use, it must surely be essential to keep the panels pressed down flat under something heavy overnight because I think warping will be inevitable otherwise. If there's no alternative, I personally would use balsa cement. I don't argue with the advantages of PVA, Aliphatics etc, but over a large surface area it's more than strong enough, light when dry and it's easy to sand.

I actually used Uhu Hart to glue my 3/8" wing panel pieces together and it's fine. I did leave them pinned down on the board overnight, but afterwards was able to carve and sand them without anything coming off, contrary to the problem that Nigel Hawes reported. He said that initially he put the wings together with cyano and when sanding afterwards, the tip panels broke off because the adhesive was too brittle. That certainly didn't happen with the balsa cement.

I used 5 minute epoxy to glue the two panels together, PVA for the ply braces. As mentioned earlier, I have fitted the wings with leading edges made from Carbon Fibre tube 5mm od/4.5 mm i/d, attached with gap filling cyano, blended in with light weight filler. I used this on the Fizza I built from the free plan years ago and it was perfect. I've still got the Fizza.

The wings are perfect and ready for covering. I have to say that I wouldn't build them from 4.5 mm and laminate together, I'd be looking for some 3/8"/10mm balsa to do the job properly, but that's my personal view.

[Delta Foxtrot]

Mike,

I got the CNC parts and no laminating was required. I had three sheets of approx 9.5 mm thick balsa per wing with some balsa strips. I used slowish seeting CA to but joint thesetogether and pinned them down over the covered plan to set properly. Just make sure not to over do the CA and have is squish out all over the bottom surface of the wing. I think Nigel hawes suggests CA for this in his build article epoxy for joing the wing roots and PVA for the braces.

After planing I made up a largish sanding board to help finish the profiling nice and evenly over the wing span. Here it is part way through. I check the leading and trailing edge thicknesses using calipers occasionally

Here is the jigging for getting the wing root dihedral angle sanded correctly in case this helps

David

[Delta Foxtrot]

Oh yes, I used epoxy for the wing tips q also as recommended by Nigel

[Mike Hardy]

OK guys take a look at this - clearly lamination is necessary!! clearly your CNC pack is different to mine - I was wondering why and thought the laser cutter could not deal with 9.5 stock

I think the 'powers that be' need to clarify (mods note)

Mike.

[Colin Leighfield]

Mike.

I'd definitely query this, or get down to your closest model shop and find some 3/8" balsa of the appropriate hardness. Whatever, good luck.

[WolstonFlyer]

Perhaps the thicker stock takes much longer to laser cut... or they have run out?

[Mike Hardy]

Just checked - all the CNC wood is 4.75 so I will be on the blower tomorrow!! Perhaps David Ashby can explain?

Mike.

[Biggles' Elder Brother - Moderator]

Mike,

we've just picked up on this. I'll mention it to David tomorrow and see what the situation is.

BEB

[Delta Foxtrot]

Posted by Mike Hardy on 24/01/2013 20:21:40:

OK guys take a look at this - clearly lamination is necessary!! clearly your CNC pack is different to mine - I was wondering why and thought the laser cutter could not deal with 9.5 stock

I think the 'powers that be' need to clarify (mods note)

Mike.

This is different to the CNC pack that I received, definitely had 9.5 mm balsa for the wing sections

[Martin McIntosh]

I am apalled to hear that packs are being sent out with 3/16 x2 instead of the correct 3/8. Just who makes this rubbish? Much like the Nihuis 72" Spit pack which I have critisised severely in former posts. I assume that they ran out of 3/8 and are just passing this off. Send it straight back to them and demand a total refund; also a a strong email to the editorial staff of RCM&E who are ultimately responsible for ensuring the quality of the merchandise marketed for their plans.

This sort of irresponsible stuff just puts people off trying to revert to basic modelling and is not representative of what we normally expect.

I have buit from truly superb plan packs in the past with CNC cut parts from the same source so why can they not do it now?

If you really must laminate that 3/16 then only use aliphatic resin. Place a piece of chipboard on top and weigh down well overnight then it should not warp.

You would be much better off just cutting wood to the plan as there is very little of this to do.

I generally get my wood from Balsa Cabin if buying on the internet and they will supply exactly what you require every time.

[Biggles' Elder Brother - Moderator]

Martin, I think that sort of rant is a bit unecessary. I have already said that we've noted the point and I'm sure that David will be on the issue tomorrow. Given that the whole thing only came to light tonight - after office hours - but has already been noted - I don't think you can reasonably expect much more than that at this point. I'm sure the matter will be put right as soon as possible. Remember, no organisation is perfect - not even my one! - but its not making a mistake which is the measure of an organisation - its what they do about it that matters. So I suggest that you calm down and give David a chance to look into the matter.

Can I just add on a factual matter, my understanding is that the plans and wood-pack side of MHS is not part of RCM&E and so not their responsibility! But of course David does have contacts and I'm sure he'll do his best to sort the matter on our behalf.

BEB

Edited By Biggles' Elder Brother - Moderator on 24/01/2013 23:17:36

[Martin McIntosh]

BEB, point taken thanks but this should never have been allowed to happen in the first place. I think that this is a viable point to be aired because we must keep plan building alive and well and not put off prospective builders with this sort of event.

Rant over!

Regards, Martin

[Colin Leighfield]

To be fair, I couldn't fault what I received, the CNC cutting was good and so was the grading of the wood. Bearing in mind that even for an obviously popular exercise like this mass build, in commercial terms the numbers aren't huge and keeping costs reasonable can't be easy. This episode with the wing panels seems to be a bit odd, particularly as mine were the correct thickness, nicely cut and a decent balance of light weight and suitable stiffness. I'm sure it will get sorted out.

I'm well on with mine and frustrated that because of having to be away for a while I can't do anything with it for the next three weeks! At least hopefully by then I might be able to get in the shed without contracting terminal pneumonia. I'm looking forward to meeting the other participants at Greenacres in June. Fortunately there's enough time in between to build another one if I total this one in the meantime. (It's far from impossible)!

[David Ashby - Moderator]

Parts and wood packs are produced by SLEC for our Plans Service, a separate business from the magazine. Needless to say though, I keep in close touch with my colleagues in all departments - plans, marketing and subscriptions, so I'll make some enquiries today and report back as soon as possible.

 

 

 

Edited By David Ashby - RCME on 25/01/2013 07:25:48

[Mike Hardy]

Thanks for all your comments, it looks like the 'hornet's nest has been stirred!! I await developments. I think the lamination process would be difficult as alignment could not be guaranteed with the parts still in sheet form. Cutting out and then laminating would guarantee alignment but but would have to be re-assembled with all the alignment problems to profile.

Hopefully MHS will replace the CNC pack.

Mike.

[David Ashby - Moderator]

Ok, news.

There have been production problems at the cutting stage, principally in an effort to get the wing parts cut. A lot of material was being wasted in order for one kit to be made and so it was decided to replace the single sheet with two.

In an effort to have as many parts pre-cut as possible and, with the model being so simple to build, we probably should have left the wings alone and left builders to work from sheet. It's easier building the wing without pre-cut ailerons too.

So, I've asked for the wing parts to be removed from the laser/cnc parts pack and the relevant (3) sheets added to the wood completion pack. Those who have their own balsa stocks or partial stocks can just buy what they need or buy the extra wood pack. It'll have the effect of reducing the price of the former and increasing the price of the latter a little.

My apologies to everyone affected. I can't get a figure for the number of packs sold with the lamination sheets (it was just a batch) and hopefully it's not too many.

Anyway, I've asked our plans service folks to help - just pop an email to [email protected] if you're affected and she'll send you some wing sheets.

Just in passing, I was chatting to Nigel Hawes earlier and he said he'd had a few emails from builders suggesting that the wood is too heavy when compared to the kits he made in the past. Nige was very very particular about his kits but his answer is 'don't worry' it flies better a bit heavier and modern power systems offer far more grunt than the set-ups he flew his models with some ten years ago.  

 

 

 

Edited By David Ashby - RCME on 25/01/2013 10:12:34

[Mike Hardy]

Thanks David,

I have sent an email to Cheryl requesting a replacement wood pack.

Regards,

Mike.

[Nigel Hawes]

Just to add to David's comments, I think the decision to supply 3/8" sheet for the wing panels is sensible. This way you can use the firmest sheet for the leading edge, the lightest for the trailing edge and the other for the mainwing panels.

I designed the wing shape such that both leading edges can be cut from a single 24" x 4" sheet, and similarly both trailing edges can be cut from a 24" x 4" sheet. I appreciate that most balsa comes in 36" lengths but at the time I was able to get an abundance of lovely grade 24" stock which was ideal for making kits of this model. I hate unnecessary waste as I'm sure you all do!

It should be remembered that at the time I designed this model, available power was low and with certain powertrains every ounce saved was a bonus! We are no longer in that position thankfully so grades are less important. Personally I would always build light and use a larger flight battery to load it up a bit; I used to get 3 10-minute flights from my Tucano on a 3s 5900 ma/h Li-Po without having to field charge or change the battery which was ideal. Destroying it in a mid-air collision at Woodvale a few years ago wasn't ideal!

As for all-up weights, I have flown this model loaded up to well over 4lbs and its performance is better in some ways (momentum and smoothness in breezy conditions) - apart from a steeper glide angle the stall is still a nod rather than a wing drop so the flat sheet wing is still tolerant. So obsessing about lightness is no l;onger necessary!

I've been up to the eyes in projects outside the hobby for the last few months and recovering from an injury but have made a start on my own Tucano which I'm building from the CNC woodpack incidentally, and will be running a feature on the build in my Fly Electric column to help / encourage anyone interested or struggling with the build sequence. If anyone has specific queries or observations before this goes to print you can always message me here.

If time allows before Greenacres I also intend to make a second, much-modified 45" Tucano to put right areas that I feel weren't their best on the original design, so hopefully it will evolve into a more scale-like Tucano with no build or operational issues - I think it's great that so many of the mass builders are "doing their own thing" with it, the hobby needs innovators!

Nigel Hawes.

[Martin McIntosh]

Hi Nigel, I liked this so much that a second is already under way, this time 61.5" span, YS powered with the retracts again plus flaps. Scaled from a full size drawing found on the internet. Someone wondered what I shall be doing for 2013 having built the first one already so now they will know.

[Ian Newton]

Hi Gents. Just started my build today and have come across an apparent discrepancy in the drawings of the fuselage. The edges of the side panels appear to be defined by triangles which is fine other than along the top rear section. These suggest that the side panels continue right up to the top sheet. There are two issues with this. 1) the 4" sheets of balsa are not large enought to do this. Not a problem in itself as a small piece can be added in the appropriate place to provide sufficient material. 2) there is a cross section view elsewhere on the plan showing triangular stock with a flat planed on it stuck to the top of the side panels to 'jack up' the sides.

It would appear that the triangles have been drawn along the wrong line on the drawing along the top rear edge of the side panels? Assuming this is the case, I can build as shown with the planed triangular stock but why not just add some material to the side panel to give the extra width and then glue the triangular stock to the inside face of the sides to give a greater surface area to stick the top panel to and also to provide the meat for the shaping required? Any comments from those that have already built their models please

[Delta Foxtrot]

Ian,

There is an error on the plan. If you look at Phil Wink's build blog you will see the error highlighted there. Nigel Hawes has also confirmed this, see earlier posts in this thread.

I built mine from the CNC pack and cut the sides back to the intended height. I made up the flat bottomed triangular stock by glueing some strip to the side of some triangular stock and this worked fine.

In hindsight I would not have bothered with the CNC pack. The major benefit if this is the front former, which would have been difficult to make with the tools I have available to me.

Good luck with the build, I have really enjoyed building mine and look forward to flying it as soon as the weather improves.

Regards

David

[Martin McIntosh]

Hi Nigel, I omitted to say that unfortunately I cannot locate that MFA reduction unit I mentioned to you earlier.

[Ian Newton]

Thanks David. Missed that earlier posting. Fuselage taking shape nicely now. Spent a while making F1 former (didn't get the CNC pack so all has to be done by hand). Looking forward to getting it built and getting it in the air. Thanks again for your reply

[Pete B]

For those still looking for a colour scheme, there's a chance to be ahead of the game (provided you get it built soon!) with the 2013 RAF Display Tucano revealed here

Looks good to me

Pete