Hurricane Building Tips and Plan/Woodpack queries

[Andy Meade]

I say go for it. The scale police should have locked doors up Phil for designing the super-stretched-intercontinental wing on the A4.

If he can get away with that, I say go for the Red Bull version.

[Peter Wood 4]

Posted by Stephen Bowdler on 26/04/2018 12:50:00:

I will mount my servos in the wing - between R4 and R5. I have bought a pair of MKS6100 servos and the matching Integrated Drive System so the whole servo / linkage / horn will be inside the wing. Maximum height is around 16mm.

Stephen. I have also bought a set for my build. However on closer study of the few published installation guides I get the impression that they will only work with bottom hinged ailerons. Am I right?

Peter

[Stephen Bowdler]

Hi Peter. No they can be used in one of four configurations - top hinged or bottom hinged ailerons and either upright or inverted servo installation. I will mount the servos inverted on the upper wing surface with top hinged ailerons, as I have done before.

[Peter Wood 4]

Thanks Stephen. I think I will also go for top hinged ailerons and inverted servos like you.

[Peter Garsden]

I used a magnetic switch on my A4, which has a blue light showing through a hole in the fuselage. There is either a swipe type, or a 3 second application type. Either way, I use them more or less all the time now. I hang a magnet from my transmitter handle so it is handy.

I used the magnetic type on my A4 and it works really well. All you can see is a small 3mm hole in the balsa. The switch also has a charging lead.

It does say you can use it with LIPO's. It can handle up to 20Amps!.

They can be bought from T9 Hobbysport for about £20 - **LINK**

[Trevor]

Well, as predicted, I didn't quite manage to hold out until the winter, and have caved in and started my build. I'll probably follow my normal practice of documenting this build by monthly diary entries on my website so I'm not sure it's worth creating a separate build log here too. However, I will let you know when each monthly instalment is published.

Meanwhile, since the first few steps do show a couple of mods/queries, I thought it best to share them here first.

First, returning to the question of aileron servos in the wings. Here's my take on this:

The cutout in the rib is reinforced by 1/64 ply on the 'top' side and 1/16 ply on the other side, to take the screws. I'm planning on the pushrods exiting through the underside sheeting as close as possible to the hinge line and maybe fit some sort of exit guard/servo cover to stop the horns getting snagged on landing.

Next the dihedral braces. I saw that Peter had fitted these full depth after the wings had been sheeted and, although I can't find anything on the plan, the size of the pre-cut braces is certainly consistent with this approach. However, I plan to fit them internally, so will be trimming them down as indicated.

Again this is based on my own usual practice rather than any claimed advantage. It does require a bit of careful thought to do the sheeting and panel joining in the right order though!

Trevor

[Peter Garsden]

I agree with you Trevor, I think there are pros and cons as to which method you choose. The same debate was had with the JP. Matt and Phil favour the strength from spanning the dihedral brace across the spars and sheet rather than trying to fit the brace inside the outer sheeting. With softwood spars, it probably makes little difference. The benefit your method is that it is easier to trim them, then cover with sheet to provide a neater job. I did think of doing it your way, but then went with the favoured method judging by the width of the ply.

[dirk tinck]

Hi all , i found that i need to twist the ailerons because of the build-in washout. Anyone the same idea ?Think i will go the amonia route?

[Peter Garsden]

Good point Dirk, didn't think of that. My ailerons don't quite line up, and the washout (lack of) may be the reason. Will look at this when I go home.

[Flyer]

If you look at the A4 Build Dirk, I seem to remember we used a stock aileron profile, but planed it to match the trailing edge. But I do remember that some did induce a twist to save balsa shavings!!

Will try and link to it later.

Ade

[Phil Cooke]

Hiya Dirk - yeah the ailerons will need either a warp (twist along their length - hot water or ammonia) or you can sand in from a slightly thicker section - just as we had to do on the A-4 - this is a natural resultant product of the washout built into the outer panels and is to be expected in all our builds.

[Peter Garsden]

Query Mr Phil.

Wing Fairings - there seems, maybe, to be a part missing - no lower wing fairing over the wing behind the leading edge.

In this picture you see a top view. The dividing former is 3mm which makes sense as it has to support 2 pieces of 1/16 balsa which are the front and rear fairing covers - yet the cut out part is 1/16. Subject to what you say Phil, I am going to replace it with 1/8"

Here is a side view of the former which shows a lower fillet - thus implying that there should be one to the rear as well?

This is a collection of the parts - the large traingular piece shows that there are 2 off - true, there are 2 in the kit - but no lower support?

I had the same shape to create with the Hawk, which employed 1/64 ply for strength - however in a bad landing this will take hammer - so is the lower section omitted on purpose?

Guidance would help please.

[Phil Cooke]

Hiya Pete, a couple of good points here which I'll try and answer - let me start by saying I personally haven't built this feature yet on my model (or the beta test fuselage!) so I haven't given these parts much of a thought until now...

Firstly, I don't think there are any parts missing in line with the instructions Matt and I supplied Sarik, you should have all the balsa parts required as per the photo below they all come supplied in 1/16" balsa.

In the plan view you are right the little 'Fillet Side' former is shown in 1/8" but supplied in 1/16" - I agree it is needed in 1/8" to allow two mating surfaces to sit across its width... So yes - REMAKE THIS FILLET SIDE FORMER FROM 1/8" balsa for ease.

The parts are all cut to the correct shape to match the cross-section below - this is the intended section immediately BEHIND the wing T/E where the fillet extends rear along the fuselage with a FLAT, planar underside.

What this view doesn't show, as you have rightly pointed out, is the material you need to 'line' the wing top skin with ONTO WHICH you would build the fillet up against the fuselage...

So in that respect, yes there is a part we need to make that isn't shown on the plan and isn't in the kit of parts.

In previous builds on similar features (my Sea Fury for example) I've always used thin ply to 'line' the wings top surface - I would suggest 1/32" or 1/64" ply in this case as being most suitable. You need ply not balsa on the base as when the wing is removed these fillets become easy to damage in handling and transport. Thin ply is best.

Looking at the plan view, I'm afraid the drawing of this feature is a little 'cartoon' like too. Matt correctly supplied the 2D layout for the balsa upper surface which curves - I think Sarik have simply positioned that part into the plan view when in reality it wouldn't extend outwards quite that far (due to the curvature) - look what happens when you lay the side former onto the plan...you can see it runs short.

So the thin ply 'wing skin' onto which we build the fillet with the balsa parts supplied (apart from the side former which needs to be 1/8" ) should be shaped as per the red dashed line I've drawn above. It should extend under the fuselage side and doubler too of course.

Hope that makes sense? I'm not at this stage of the build yet, I think you are 'pathfinding' through these final stages Pete! Keep up the good work we are watching!!

Edited By Phil Cooke on 10/06/2018 22:15:26

[Peter Garsden]

Thanks Phil. Excellent guidance as always.

You have confirmed what i suspected. So just to be clear:-

1. I will replace the side formers with 1/8 instead of 1/16 - in fact I have glued the two supplied together and will draw round that to make another in 1/8
2. I will replace the front fillet bottom piece with 1/64 ply.
3. I will make a new bottom rear fillet also out of 1/64 ply but make it smaller - I will cut it over size because I can always trim it off. 1/64 cuts like balsa but is pricey. I have a big sheet of it.
4. I might make the side fillet out of 3/16 as it doesn't give much margin for error when joining two pieces that will take a lot of purchase.
5. I might add another side fillet for extra support. Will see how I go.
6. Might wet the top pieces to aid curvature when gluing in position.
7. The top fillet pieces will have to be chamfered to make the fit the fuselage sides snugly.

Edited By Peter Garsden on 11/06/2018 20:12:37

[Bryan Tucker]

Help Phil and/or Peter

I've just been looking at your wing fairing posts, they are very helpful and I'm about ready to make mine.

This may sound like a stupid question, but I've never fitted wing fairings before. So, do you bolt the wing on the fuselage and then build the fairing glued to the wing and get a good close fit against the fuselage? OR is the fairing glued to the fuselage and just resting on the top wing skin?
Either way it looks quite a vulnerable structure for a heavy landing to wipe out!

Any help would be appreciated.

Bryan

[Phil Cooke]

The fillet fairing needs to be glued to the fuselage, but to make it accurately you build it with the wing mounted to the fuselage if that makes sense.

Key is to 'line' the wing upper surface with the thin ply sheet which will act as your base and foundation for the assembly - 1/64" or 1/32" is probably best... same if you are building up the fillet using balsa as per the plan or in foam as others have done - see Dirk Tincks build blog - blue foam and balsa.

I promise you it will not be vulnerable to damage it sits on the top of the wing and is well protected - even if the wing comes off nastily at an angle the fuselage sides will protect the fillet.

Having considered both methods and wanting to extend the fillet further forward than the drawing and parts show for scale, I will be making my fillets (quite shortly) using blue foam and balsa covered in brown paper/PVA then glass.

[Bryan Tucker]

Thanks Phil, that clears that up for me. I think I'll stick with balsa and thin ply as per your earlier post - at least I'll now have the fairing attached to the correct structure. I can see that it will be much less prone to damage when attached to the fuselage.

[Peter Garsden]

My blog has quite a good description of how I fitted the fairings Bryan - see **LINK**

[Bryan Tucker]

Peter, thank you for letting me see your blog. I can see clearly how to fit the fairings. I can also see the pit falls in making the radiator before finishing the wing to enable it to clear the wing bolt plate - hadn't spotted that one.

Hope to see you in September although I have a lot of hurricane to build yet.

[Trevor]

I'm just looking at fitting the upper fuselage formers and either I've got an attack of brain fade in this hot weather or there's a bit of a discrepancy between F5 and F6. As you can see from the pic, the base of F6 is wider than F5.

With the fuselage pulled in onto the top of F7, F5 slots into position nicely but, in my case at least, F6 is going to need trimming somewhat to fit in between.

Also, it looks like the snake hole has been missed from F5 (i'll be routing my snakes differently, so haven't given this aspect much thought)

Did anyone else find F6 to be a bit of a misfit - or am I trying to fit it in the wrong place!

Trevor

[Phil Cooke]

I don't recall having to trim F6 to fit on width Trevor, can I ask if you've pulled in the tail yet as when that's done first it 'bows' open the top of the fuselage a little and you may find F6 fits slightly easier?

As for the snake holes, I think if you have the servos positioned as plan and you are using std size units, then you probably wont see either former interact with the snake, I found it sat too low - see below. I added a local mount on F4 and fitted the snake outer in F7, F8 and F9 - but you can see it bridges F5 and F6.

[Trevor]

Hi Phil, thanks for the prompt response and useful photo. Yes, I do have the sides pulled in onto F8 and F9. However, I’m only working with the lower halves of the sides at present since I plan to plank most of the upper section to avoid the need for Ammonia treatment.

I can’t see any gaps in your picture but I wonder whether the triangular reinforcements at the base of F5 might be an indicator that you fitted it after F6 and found that it wasn’t a particularly snug fit? Anyway, I think my only sensible course is to sand back the lower edges of F6, at least so that it isn’t any wider than F5.

I’m finding that building at this time of year is a rather fitful process, family, flying and other outdoor commitments and opportunities taking precedence over time in the workshop. The good thing though is that when major sanding has to be done (the lower nose section and wing tips for example) one can at least do it outside avoiding the need for Darth Vader impressions! Will it be finished in the next 6 weeks? Who knows!

Cheers,

Trevor

[Brian Boucher]

I have just completed mine and did a trial balance and found that had to add 1lb 1oz to get it to balance giving me a flying weight of 4lb 1oz , i have covered it in oratex and spray painted i would not have think that would have increased over a 1lb on the protoype weight any thoughts ???

[Phil Cooke]

Similar question in Peter Garsden's thread - where I placed a lengthy answer earlier today... **LINK**

In summary, I think this AUW is a combination of denser wood in the Sarik kit than used on the prototype (it's worth pointing out that Matt is renowned for building light as well!) combined with your additional scale features, paint, decals etc (there were none on the prototype) - I would think they will all come out at 3.5lb minimum finished and ready to fly. Are you carrying an extra servo for the rudder? Lights? Additional power source for lights etc etc?

Nothing to worry about - the AUW will be fine - the prototype flew very lightly loaded. I guess some advice for anyone still to make up and sand the tail section - profile them fully with nice, thin T/E and if you consider your supplied stock to be too hard and heavy then recut them from lighter material.

There are a few Hurricanes approaching the finishing line - I'd better set up a 'Finished Model' thread in this section so we can all see them for inspiration (some of us are still left with quite a bit to do!!!)

[onetenor]

1/64 or 1/32 ply covering for upper fuselage better than planking or Ammonia soaked balsa. Lovely stuff to use and finish. As alexander would say "SIMPLES" .