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Hurricane Building Tips and Plan/Woodpack queries

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Phil Cooke08/03/2018 21:23:56
1968 forum posts
1335 photos

Please use this thread if you have any general questions regarding the PSS Hurricane build or require any clarification about the drawing or woodpack content.

Phil Cooke08/03/2018 21:39:17
1968 forum posts
1335 photos

We've discovered a minor issue with the Hurricane fuselage sides - nothing wrong with the parts as such - but there is a cutting and dressing operation needed which I wasn't expecting due the position of the laser cutting profiles on the 1/8" wooden panels.

The fuselage profiles (top and bottom halves) haven't been cut right to the edge of the balsa panel as I would have perhaps expected - meaning that if you simply butt join them as supplied they will end up being approx. 1/4" too tall. Having checked the parts, we will have to trim the panels (both top and bottom) carefully with a straight edge between the terminating point of the laser cut, front and rear.

Here's the two panels as supplied - you can see in the red circles where the laser cutting ends, a few mm short of the edge of the balsa sheet. Perhaps this has been done intentionally by Sarik to avoid warped or damaged joint lines, or to avoid variance in sheet dimensions effecting our build?

fus side rear upper marked.jpg

The result of this means the fus sides will be too tall unless we dress...

fus side rear lower marked.jpg

To fix? - simple enough - we need to accurately draw a straight line between the two points where the laser cutting ends - it will look like this at the back...

fus sides rear marked.jpg

and like this at the front...

fus sides front marked.jpg

Mark and cut carefully, as this ultimately dictates the incidence of the tailplane relative to the datums...Use the 2D fus layout on SHEET 2 of the plan to position your parts and gauge exactly where you need to make your cuts. The dotted or hashed line running midway through the 1/2" x 1/8" balsa doubler is exactly where the fuselage join should lie. Use the definition around the cockpit area and the wing saddle to best position the two panels before marking your cut.

Ill contact Sarik immediately to see if all future kits can include an additional cut with the laser from front to back - but for all those kits already ordered/supplied we will have to work this additional op.

onetenor09/03/2018 01:38:41
1538 forum posts

A full length cut I assume just to be totally clear.

Phil Cooke09/03/2018 06:32:10
1968 forum posts
1335 photos

Yes, a full length, straight cut between the two points where the laser cutting ends. The parts will then sit perfectly over the 2D fuselage side layout on sheet 2.

Stephen Bowdler09/03/2018 18:04:21
30 forum posts
22 photos

Phil, can you clarify the wing washout details please.

The plan, page 2, state 1.5 deg in one place and 2 deg in a different place. Which is correct?

They also show a 1/16 x 1/4" strip flat under the full length of the outer panels to achieve this washout. Surely this should be a tapered wedge. Or am I missing something?

Phil Cooke09/03/2018 21:42:36
1968 forum posts
1335 photos

Hi Stephen,

Not sure why the plan quotes both 1.5 degrees AND 2 degrees washout on the plan - we've clearly all missed that in our proof checking!! The 1/16" flat strip mounted under the sub T/E at rib R9 will effectively give the required 2 degrees of washout, so lets go with that as the correct figure and please ignore the 1.5 degree notation.

As for the tapered wedge or constant thickness sheet under the sub T/E when fitting the top sheeting - in this particular build - no tapered wedge is needed!

The key here is the wings are built in three separate panels (centre panel and two outer panels) and joined only after the top skins are attached to the outer panels. There is no washout in the centre panel. So considering the outer panel only, if you raise the entire sub T/E as shown by 1/16" - by inserting a strip of 1/16" balsa sheet - and then pin the wing down onto the board and onto the washout sheet - the correct panel 'twist' will be achieved. How so?

This is simply a function of the reduction of axial chord as you move outboard from Rib 3 at the root to Rib 9 at the tip. As the ribs lengths get shorter and shorter, the angle of 'twist' increases if you assume the entire span of the panel is held flat against the board at the spar location. To aid this description, please refer to the figure below.

washout wedge.jpg

Clearly dimension A is approx. 3 times that of dimension B - so if the entire sub T/E is raised by a constant 1/16" and the wing is mounted on the board along its spar then the angle of T/E deflection will increase as we move outboard.

Once the skins are attached and the panel is unpinned from the board, we will join the outer panels to the centre section and accurately align the mating Rib 3s. This is exactly how the prototype wing was assembled, and it all went together without a hitch and with the required wash-out pre built into the outer panels.

Hope that all helps and my written explanation makes sense...

Stephen Bowdler10/03/2018 18:22:12
30 forum posts
22 photos

Ah. Now it makes sense. Very neat. Thanks for the explanation Phil.

Another question. The plans don't show any shear webs between the lower and upper spars (except for the panel joiners around rib 3). I have never built a wing without shear webs. Is this correct.......?

Phil Cooke11/03/2018 20:19:10
1968 forum posts
1335 photos

It is correct, in regard that was how the prototype was built, we felt the wing was stiff enough without the webs - certainly no issues were found. No harm in adding them if you so wish, but not strictly necessary in this instance.

Stephen Bowdler13/03/2018 19:16:41
30 forum posts
22 photos

I have found a minor problem with the battery tube. It is 3mm longer than shown on the plan and when assembled into the the nose sub assembly, back flush with the rear face of F3, it protrudes 3mm in front of the horizontal formers F10.

battery yube.jpg

It appears to be intended to pass through F1 and not butted up to the rear face as shown on the plan.

I simply sanded the tube back to the faces of F10 and butted F1 against them all. Then everything aligns with the plan.

Phil Cooke17/03/2018 08:59:57
1968 forum posts
1335 photos

I've found last night when positioning the central 'box section' of formers prior to fuselage assembly that formers F3 and F7 both required a little opening out at the 1/2" x 1/8" doubler position.

Having assembled the fuselage sides exactly as per the 2D layout on sheet 2 - I positioned the fuselage side accurately over the sheet 1 side profile using the wing saddle and base of F3 and F7 as reference. Everything lines up perfectly at the extreme front and rear (position of doubler and tail seat etc) so all looked good.

F3's height was governed by the base (it sticks below the fuselage side as intended) - aligned also on the wing dowel hole and it sat nicely on top of the 1/32" doubler (middle green circle) - positioned such I got a 2mm 'clash' with the 1/2" x 1/8 doubler as shown by the red circle.

f3 bind.jpg

This will need relieving to enable assembly, I will remove a little material from the lite-ply former - this will leave me with a small gap above the doubler but this won't cause any problems.

F7 is similar - seen below viewed from the rear.

f7 bind.jpg

Vertical position is governed by the engaged feature in the green circle which butts up against the fuselage side - the former bridges the 1/32" doubler ok but again in this position you are left with a 2mm clash in the red circle. Same remedy required. No gap here above as the former terminates on the doubler.

Considering the rest of the assembly, I fear we might yet see the same issue on formers F2 and F1 as their vertical position is governed by the battery box sub assembly stage. Everyone's case will be bespoke, dependant on how we've exactly trimmed the fuselage sides and exactly positioned the doublers... so it's a case of dry fit, measure twice, amend the parts to suit. Ill talk to Sarik for a double check in CAD and former amendment for future kits.

Edited By Phil Cooke on 17/03/2018 09:15:19

Graham Green17/03/2018 09:25:49
6 forum posts
4 photos

Hi Phil, Thanks for the heads up onthe formers.

While they are checking the drawing for the above, perhaps they might also check the radiator on the wing centre section drawing as it differs from the section relating to the construction of it. The radiator section is correct to the parts supplied but the view on the wing itself shows wider spacers to the plywood 'sides'.

Whilst on, may I also ask as to why the canopy slopes downwards to the rear as I thought it should be level, i.e. parallel to the horizontal datum line?   Just curious.

Right! back to my building board.

Edited By Graham Green on 17/03/2018 09:34:25

John Donohoe17/03/2018 09:56:50
2 forum posts

Hi, I think this kit is really rubbish. There are so many mistakes on it that the money you paid for is ridiculous. Surely when one make a kit they should assemble it first to make sure everything is spot on.

Phil Cooke17/03/2018 09:58:49
1968 forum posts
1335 photos

Hi Graham,

Yes I'd noticed the wing plan view of the radiator differed from the radiator assembly drawings on width too - as you've stated the parts supplied match perfectly the detailed sub assembly drawings at the top of sheet 2 - its just not shown the same on the wing plan... I'll raise that with Sarik too.

Not sure about the cockpit view... I see what you mean about it sitting lower at the rear than at the front as drawn - I'm sure in reality it will trim up correctly and sit flat as required - certainly the prototype looked spot on IMO.

prototype 4.jpg

Phil Cooke17/03/2018 10:13:18
1968 forum posts
1335 photos
Posted by John Donohoe on 17/03/2018 09:56:50:

Hi, I think this kit is really rubbish. There are so many mistakes on it that the money you paid for is ridiculous. Surely when one make a kit they should assemble it first to make sure everything is spot on.

John that's a little too negative for my liking - there will always be development issues with any new kit. I can assure you a lot of hard work has gone into the development of this new production plan/woodpack and a beta test kit WAS assembled to identify any issues. A number of small changes were made following that under fairly difficult circumstances as the product had been worked by both Traplet and Sarik.

I'm happy to take full responsibility for the decision to proceed from 1st March as that was the timeline I wanted to achieve for the PSSA event later this year - giving us 6 months to build and finish as a community.

As modellers, all these issues are easily fixed through calm identification, discussion and simple remedy... that's exactly the purpose of this thread. Its certainly not intended to be used as you did.

Callsign Tarnish17/03/2018 19:08:03
24 forum posts
Hi John, as a viewer from the outside I think you're being overly negative in such a public forum. Can I just ask, have you ever had a plan published and a kit created? If you have then the PSSA might welcome your insight.
Flyer17/03/2018 20:41:14
394 forum posts
48 photos

In response to the negative view expressed, I feel I must respond in defence of the guys that have made the effort to give us a workable plan and short kit to produce a flying model.

I built the previous A4 Skyhawk, encouraged by the PSS group, to produce something that I felt was way beyond me. The result was a flying model, although not perfect, but did give me more skills to produce something more advanced.

To my knowledge, these guys have not profited to any extent form their efforts. Given the number of companies that have fallen by the wayside in the last two years, I believe that we need guys like this to promote the hobby to new comers. Give them a break. As you can see, if there is a problem with the plan/pack, then a workable solution is provided.

I am grateful that guys with their extensive knowledge freely give up their own time to assist idiots like me to produce models that I think could be beyond me.

Given that the solutions are posted up, quickly I must add, the chance of everyone producing a nicely flying model is enhanced.

I have been enthused by the efforts of the PSS in promoting model building,and as a result, have several models on the building board. Without the help of the PSS members, I would never have achieved what I have so far, let alone what I could attain in the future.

Constructive criticism is fine, negative comments can be left on messaging boards.

Keep up the good work lads


Graham Green18/03/2018 10:06:39
6 forum posts
4 photos

Hi Phil,

Thanks for reply above re rad and canopy. Yes, the canopy looks fine on your lovely prototype model and looking at the supplied canopy I don't think there should be a problem getting it to be horizontal' when fitted. it was just as it was on the drawing that confused me (It doesn't take much! lol)

May I also say thank you Phil for taking the time to draw, develop, test fly the prototype and make it possible for other modellers to join in the mass build of a Hurricane for PSS, especially in this 100 year anniversary of the RAF.

To design and construct a new model takes time and effort to achieve a finished item and sometimes errors do creep in ( I know, I used to be a draughtsman, so have made a few due to 'work blindness' but as modellers we overcome them and carry on!

Thanks again Phil, and if I knew how to put up a picture on here without the message that I have too many 'characters', then I would share a pic of the colour scheme that I am thinking of doing.

Phil Cooke18/03/2018 21:05:16
1968 forum posts
1335 photos
Posted by Graham Green on 18/03/2018 10:06:39:

May I also say thank you Phil for taking the time to draw, develop, test fly the prototype and make it possible for other modellers to join in the mass build of a Hurricane for PSS, especially in this 100 year anniversary of the RAF.

Thanks for the support Gents.

Graham, I should point out that although I've been involved in the realisation of this production woodpack with Traplet and Sarik, the original design and prototype testing work was all completed by PSSA member Matt Jones - its his name on the plan not mine!

I'm glad you recognise and appreciate the link to RAF100 - it will be great to see a large group of Hurricanes at our September meet upon the Orme - our own little PSSA tribute to 100 years and in September - BoB weekend too!

Graham Green19/03/2018 02:05:02
6 forum posts
4 photos
My apologies to Matt for omitting to thank him too, which i do, sorry for that.
Brian Boucher19/03/2018 11:38:32
11 forum posts
6 photos

I would like to thank the developers of the hurricane and that this is the place for building tips and small corrections required and not the place for criticizing all the work that has gone into this project.

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