Author Topic: Furrari diffuser wing.  (Read 10986 times)

Furrari

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Furrari diffuser wing.
« on: July 28, 2017, 10:15:58 PM »
Those of you who have followed my Furrari Build may have noticed that the diffuser wing I was building disappeared from the narrative before it was finished.

There's a good reason.  I was ready to bond the end winglets on when my good lady placed a load of cat bedding on it.  As I had to prioritise other jobs this was left.  When I went back to it it had taken a set.  I tried to straighten it using a hot air gun but it cracked at one of the joints.

This thread is the story of the design, build and fitting of the new, super wing.
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

seriph

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Re: Furrari diffuser wing.
« Reply #1 on: July 29, 2017, 12:07:27 AM »
Keen to read the story!
Steve

wishing we could get cars like these legally registered downunder

Furrari

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Re: Furrari diffuser wing.
« Reply #2 on: July 29, 2017, 09:28:54 AM »
First the design of the old wing.

The old wing was made up of 50mm ( 2" in old money) long sections of wing profile which were clamped to the DNA built diffuser wing and were initially  held together by using a 3D pen.  This was was to get the curvature of the wing.  Sections were fixed to each other by three pins going into holes in the corresponding face of the next section.

I had taken the profile/design from Thingyverse.  The method of location/attachment was the weak point so in the bonding phase I ran several pieces of welding wire through the sections and filled them with sikaflex.  This why it cracked rather than broke.

In hindsight, due to lack of experience,  it was a poor design.  Not to worry, in the philosophy of kit car R&D we learn by our mistakes.
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

seriph

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Re: Furrari diffuser wing.
« Reply #3 on: July 29, 2017, 09:50:29 AM »
learning = willingness to get it wrong in order to get it right. :)
Steve

wishing we could get cars like these legally registered downunder

Furrari

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Re: Furrari diffuser wing.
« Reply #4 on: July 30, 2017, 09:33:10 AM »
Steve.  If it was easy anybody could do it.  I don't mind how many times I get it wrong, providing each attempt is an improvement on the last and I'm moving towards my final objective.

Anyway on to the new wing.
Because I still have the old wing I can use it as a template.  It measures 970mm across the inner "horns" and if I stand it up on these horns the centre is 75mm higher.  The new wing will be built of a number of sections 200mm long following the curve established by these dimensions and have a large tongue and socket arrangement on each end to plug into the next unit to give as much strength as I can at the bonding stage.  I'm probably going to stake through these areas after bonding to put the joint in sheer rather than just in tension.  

The design. (Layout)
Because I want to have these units follow the curve the joint faces need to follow a taper like a slice of cake the first part is to layout the plan.  Using the 3D program I can establish a circle passing through the three points I have from the template.  This gives me the centre point of the circle I need.
The print bed is 220 long ( that less the tongue of 15mm gives me the 200 length). so I've drawn a vertical centre line for the section and two vertical lines, 100mm either side of this as guides.  Using the curve constructin line, the centre point of the curve and the two vertical lines I can draw the sides of the section.

I'll show the design of the wing profile in the next post as this is enough for now.

Just two pics.  The first an overall view of the layout and the second a close up of the plan/layout of the section before the profile is added.

Tomorrow the profile and the final design of a section.

« Last Edit: July 31, 2017, 09:56:49 AM by Furrari »
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

Furrari

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Re: Furrari diffuser wing.
« Reply #5 on: July 31, 2017, 09:37:31 AM »
Not much you can say about today's offering, it's all more or less just pictures.

First pic is the profile.  Not bothered about a true wing shape as it's mostly a cosmetic thing.   Hay, DNAs wing, about 50mm away is backwards.  The dotted, vertical line through the larger end is the line that will revolve about the centre point of the layout circle.

Pic2.  is a plan view of the revolved wing.  In this view you can see how the lines in the layout view ( previous post) form the shape of the sides.  I've not used the full width of the bed but have kept the rotation (extrusion) to a symmetrical 5.5* on each side of the centre line.

Pics 3&4 show the tenon and socket shapes for bonding the sections together.  All edges have a small fillet on them to prevent a line of weakness on the joint line.

Tomorrow we start printing.
« Last Edit: July 31, 2017, 10:00:23 AM by Furrari »
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

Furrari

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Re: Furrari diffuser wing.
« Reply #6 on: August 01, 2017, 08:48:29 AM »
So on to printing.

Well it's not gone so well.  To recap, the previous wing was made up of 50mm sections.  These were made of ABS and printed OK.  These are about 180mm long.  ABS can be difficult to print given its propensity to crack and warp if printed in large blocks, it's a cooling thing.  That's what happened to my prints.  After three attempts I've given up with ABS.  The last attempt was with a slurry of Prit and Elnet hair spray, even that didn't hold the print to the bed.

I'm reluctant to use PLA on a part that could see significant strain on it so I've had a browse on the web and ordered some PLA+ from a company called Rigid Ink.  This won't be here for a couple of days so there is a pause in production and this thread.

ABS is strong but prone to warping and not sticking to the print bed.
PLA is very easy to print but is nowhere near as strong as ABS.
PLA+ is supposed to be nearly as easy to print as PLA and nearly as strong as ABS.  We'll give it a go and see.  I suppose finding  the right material to print with is just part of the learning curve.

Hope to be back in a couple of days.

Forgot to say, thinking ahead to the assembly stage I've ordered a 1200mm sash clamp (cramp) to clamp it all together.  Never needed one of these anywhere near as long before, but I'm an engineer not a chipy (carpenter)
« Last Edit: August 01, 2017, 08:58:13 AM by Furrari »
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

Furrari

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Re: Furrari diffuser wing.
« Reply #7 on: August 02, 2017, 11:36:50 AM »
It's not all computers, 3D printers and hi-tech.

This is the assembly fixture.  It's just the old one resurrected and some new masking tape.  Two bits of wood, three screws and some masking tape.

Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

Furrari

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Re: Furrari diffuser wing.
« Reply #8 on: August 03, 2017, 07:19:40 AM »
Back to printing.  The PLA Plus has arrived and I've printed the first section.  It's printed with no failures.  Overnight it's "warped" slightly to give a gentle curved wing shape that I couldn't have designed in if I'd tryed.  I printed it with five solid layers on all the surfaces to give plenty to rub down.  It feels very solid.  Only draw back, the surface finish, is in places, terrible.  I'm talking to rigid ink about this.  I'm not really bothered about the poor surface finish as it will need filling and sanding at the assembly stage anyway, strength is more important than finish.

As each print takes about ten hours and I don't like printing overnight that's me tied up for the next few days.  Back later.
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

Furrari

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Re: Furrari diffuser wing.
« Reply #9 on: August 06, 2017, 10:31:33 AM »
All these sections need securing to the assembly fixture.  I'm printing some clamp pad things to clamp these sections to the bed of the assembly fixture.  They're designed to fit over the front bit of wood which controls the final curvature, holds the section at the back to hold it to the wood and spread the clamping force over the entire print.  It also has to fit under the rail of the sash clamp for holding it all together at the bonding stage.  I'll print six to start with to bond the first three sections together.

Three pics of the clamp.

Pic 1). The profile which shows what I was wittering on about in my first bit.

Pic 2). The finished design.  The castellations at the end are to stop the bits of wood that give the clamping force from slipping.

Pic 3). Showing how they fit round the wing section.

Next on the wedgies that hold it all together during bonding.

Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

Furrari

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Re: Furrari diffuser wing.
« Reply #10 on: August 07, 2017, 10:20:47 AM »
The Wedgie.( Seriph, no not that sort)

Because each wing section tapers I need to square off the ends to simplify clamping.  Each face with have an insert during clamping to square the ends up to prevent the clamp slipping.

Pic 1). The first wedgie.

pic 2). The wedgie in place.

I won't bother with any more pictures of the individual bits as they are just variations on a theme.
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

seriph

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Re: Furrari diffuser wing.
« Reply #11 on: August 07, 2017, 01:30:25 PM »
This is so bloody cool :) - decent skills dude!
Steve

wishing we could get cars like these legally registered downunder

Furrari

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Re: Furrari diffuser wing.
« Reply #12 on: August 10, 2017, 12:45:45 PM »
All the bits coming together.  Just a picture of the first two bits in the assembly jig.  No more pics until the full wing is assembled as it's just an expansion of the bits.
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

Furrari

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Re: Furrari diffuser wing.
« Reply #13 on: August 11, 2017, 03:26:45 PM »
The main wing assembled ( still in its assembly jig).  I can still use the original centre and intermediate mountings but the end mountings/winglets won't fit.  With the tapered end faces of the new wing designing these is going to be fun.  I think a mounting/jacking pad to hold the new wing in place to let me check how it sits under the existing wing will be a good idea.
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.

Furrari

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Re: Furrari diffuser wing.
« Reply #14 on: August 13, 2017, 09:23:42 AM »
I've offered up the assembled wing and held it in place with tie wraps ( no pics as I'm sure you all know what a tie wrap is).  Not bad but I think in needs to be a bit longer so I'm printing another section.
I also held an old winglet to the end.  I think this bit needs a redesign.
Not all problems can be solved with gaffer tape.  For those there is WD40.
Not even gaffer tape can fix stupid, but it can mask the sound.

If you can’t buy it or steal it you have to make it.