HM Airship No 1, Mayfly

[Chewbacca]

I must be mad.  I struggle to finish one model in most GBs.  But I've fancied doing this for a while and I can always plead that "big boys made me do it".  So not content with one entry into this GB, my Lynx from HMS BRAVE in 1991, 

 

 

I'm going to have a go at 3D printing HM Airship No 1, also known as Mayfly, the Royal Navy's first rigid airship.

 

Technically, it's outside the timeline of this GB as it was built in 1911 (and broke in half prior to its maiden flight, but after consulting with @LorenSharp a couple of months ago, who in turn consulted with the oracle of all things airship, @Martian, it was decided that since it was the Royal Navy's very first heavier than air craft, it was acceptable.

 

I have started some of the drawings in CAD 

 

 

And it had been my intent to cover these with tissue.  But at club night in the week everyone said I would be mad to do that so I shall investigate filling in the holes and printing the entire outer structure.  Since Mayfly was designed to float on its (her?) gondolas, I am more than a little concerned that that will make it extremely heavy and the gondola supports will not cope.  Watch this space.

 

 

Was at the FAAM at Yeovilton yesterday and got some great photos of photos of Mayfly that will help with this.  Not sure if I'm allowed to post them since there are photos of someone elses images? 

 

 

Edited August 15 by Chewbacca
Typo corrected

[LorenSharp]

Now thats what I call going for the Gold! This will be an ostentatious(Always wanted to used that word)and very historical addition to the GB Chewbacca.  And A Printed version to boot!

[heloman1]

Now this looks very ambitious and on top of your Lynx build. I see you have a typo in your intro, a Pound sign and a D or is it expensive D printing?

 

Colin the Wessex grubber.

[MARADER]

Will a zeppelin be in a scale 1/48?😉

[CliffB]

Great stuff and a subject that's new to me.  The fabric almost looks translucent in the photo?

[Chewbacca]

On 24/07/2023 at 08:39, heloman1 said:

Now this looks very ambitious and on top of your Lynx build. I see you have a typo in your intro, a Pound sign and a D or is it expensive D printing?

Thanks Colin.  Typo corrected.

 

On 24/07/2023 at 09:49, MARADER said:

Will a zeppelin be in a scale 1/48?😉

Well if it were it would definitely be expensive D printing as Colin suggests above!  I wanted to do this in 1/350 scale but Mayfly was pretty big and in that scale would have been 446 mm in length which was why I opted for 1/600 to bring it down to a more manageable 260 mm.  1/48?  Hmm?  3.2 m in length?  I think not, especially when my 3D printer's print bed is limited to not more than about 120 mm.  Or what Mrs Chewbacca might say to me when she's trying to see the television past this behemoth parked in the lounge!

 

On 25/07/2023 at 06:12, CliffB said:

The fabric almost looks translucent in the photo?

 

I know what you mean.  I'm unsure at the moment whether it was light grey or silver.  More research required.

 

Thanks everyone for your interest.

[Chewbacca]

Pleased to report that resin has been poured and the first few sections of Mayfly have been printed.

 

 

 

 

 

In total I need 6 of those main centre sections so one more needed plus a replacement for the one that didn't print correctly.  I wonder why, when 4 out of 5 print perfectly, that one decides not too.  I wonder if I have some defective parts of my screen?

 

And I have no idea why there are those lines across the nosecone.  They are visual only in that rubbing a finer over the they are completely smooth so should disappear under the printer.

 

Thanks for watching

[LorenSharp]

Looks like it might be a touch of "Z wobble" on the nose Chewbacca. you may need to a a little bit of white grease or PTFM oil to the guides. I usually have to add lubricant about every couple hundred hrs or so.

[Chewbacca]

Z wobble?  That's a new one on me!  I'll have a look to see what needs to be done.  Thanks

[LorenSharp]

Here's a link that might help.

https://3dprinterly.com/8-ways-how-to-fix-resin-3d-printer-layer-shifts/

[Chewbacca]

Thanks for that.  Useful site for a variety of potential issues.  The bizarre thing with that nose cone is that it is only a set of visual lines which are actually exaggerated by the macro photography - running a finger over the supposed layer and there is barely any ridge and what is there will come off easily when I take a sanding stick to it to smooth off where I have removed the attachment points.

 

All sections are now printed and have been removed from their supports.  I thought I'd be clever and aid alignment by including plugs and sockets on either end.  Unfortunately, although the attachment plugs are fine, I don't think I left sufficient extra space on the sockets to allow for the print tolerances and none of them fit.

 

Male end

(the bits you can see on the inside are shavings where I have already sanded the attachment points from the other end)

 

Female end

You can see the central socket but it is fractionally too small for the plug on the other end.  The sockets around the edge are barely discernible but then they are only 0.3 mm deep.

 

So in the end I sanded off all of the attachment plugs and decided to rely on butt joins instead.  My original plan on doing this was to print all of the frames and join them with 20 thou evergreen strip.  I'm glad I didn't or I would have an awful lot of sockets to neaten!

 

And then assembled the basic structure

 

The fact that I don't have any alignment plugs shows itself in this photo as trying to align the different sections perfectly while the CA sets was a little challenging.  This was made worse by the fact that the sides of each section aren't entirely parallel.  I think it must be printing tolerances but all of the sections have a slight variance in diameter from one end to the other.  It's not a lot - probably 0.1-0.2 mm - but it's enough to demand a bit of sanding on each of the 12 faces at each join.  This is the worst example:

 

 

I've aligned them all on one side which will become the top and left the misalignments on the lower side where hopefully if my sanding isn't perfect will be less noticeable.

 

It's surprisingly light - much lighter than I was expecting - so I am now hopeful that the gondola supports when fitted may actually take the weight without the need to drill and fit clear perspex supports.

 

Next job with this once the body (hull?) sanding is complete is to print and fit the keel plus finish drawing the gondolas for which I am struggling to get the shape from the photos.  I do have one drawing (below) that shows the plan of the gondolas, but that doesn't align with the photos that appear to be more rounded, at least at one end, nor the large scale model at the FAA Museum which are a very peculiar shape.  I shall continue to investigate

 

 

 

FAAM model forward gondola

 

FAAM model aft gondola

 

This is the render of my initial attempt from the photos.  More effort needed!

 

 

Thanks for watching

[LorenSharp]

Looks great. Sometimes 3-D printing ends up more of a deft and dark art than a science.  Some things that you wouldn't think of being connected  can effect the final outcome. And that includes cleaning and curing. But the fact you got 9 pieces all to fit together within a 100um is amazing. keep it up!

[Chewbacca]

Thanks.

 

Done some more playing around with the gondola CAD.  This looks more like it I think:

 

 

[heloman1]

Wow!!!

 

Colin

[Chewbacca]

Printed the keel and the gondolas.  Had to print the keel in two halves - one printed fine the other had a couple of deformed girders so have repeated that and now have two good versions.

 

Pleased with how the gondolas came out.  I was half expecting the windows to not print and have to replace those with clear acetate sheet.

 

 

And have got the first coat of primer on the keel and the hull, the latter primarily to show where more sanding and filler is needed.  Not as much as I initially thought.

 

At this rate, Mayfly is going to be finished well ahead of XZ733.  But I'm about to hit a stopping point.  What colour was she?  Light grey or silver dope?  Looking at the online imagery, I want to say the latter:

 

 

Now interestingly, that photo doesn't appear to show the keel, yet this one does:

 

 

I used this as the profile drawing which also shows a keel

 

 

Yet this doesn't

 

 

So I now don't know either what colour to paint her or whether I need to fit the keel!  I think I'll head back to Lynx-land!

 

 

[LorenSharp]

1 hour ago, Chewbacca said:

Printed the keel and the gondolas.  Had to print the keel in two halves - one printed fine the other had a couple of deformed girders so have repeated that and now have two good versions.

 

Pleased with how the gondolas came out.  I was half expecting the windows to not print and have to replace those with clear acetate sheet.

 

 

 

And have got the first coat of primer on the keel and the hull, the latter primarily to show where more sanding and filler is needed.  Not as much as I initially thought.

 

At this rate, Mayfly is going to be finished well ahead of XZ733.  But I'm about to hit a stopping point.  What colour was she?  Light grey or silver dope?  Looking at the online imagery, I want to say the latter:

 

 

So I now don't know either what colour to paint her or whether I need to fit the keel!  I think I'll head back to Lynx-land!

 

 

You may want to see what our Favorite @Martian knows as far as what colour may be involved.. He has done extensive research on many things Airship.

I wasn't surprised how your pieces were aligning. I thought it looked like Pretty much spot on from the individual pieces.

[Old Man]

This is marvelous, Chewbacca!

 

A wonderful project, progressing beautifully.

 

 

James

[Martian]

4 hours ago, Chewbacca said:

Printed the keel and the gondolas.  Had to print the keel in two halves - one printed fine the other had a couple of deformed girders so have repeated that and now have two good versions.

 

Pleased with how the gondolas came out.  I was half expecting the windows to not print and have to replace those with clear acetate sheet.

 

 

And have got the first coat of primer on the keel and the hull, the latter primarily to show where more sanding and filler is needed.  Not as much as I initially thought.

 

At this rate, Mayfly is going to be finished well ahead of XZ733.  But I'm about to hit a stopping point.  What colour was she?  Light grey or silver dope?  Looking at the online imagery, I want to say the latter:

 

 

Now interestingly, that photo doesn't appear to show the keel, yet this one does:

 

 

I used this as the profile drawing which also shows a keel

 

 

Yet this doesn't

 

 

So I now don't know either what colour to paint her or whether I need to fit the keel!  I think I'll head back to Lynx-land!

 

 

Both are correct Ralph. When Mayfly was first weighed off she was found to be over weight and steps were taken to lighten her structure. It therefore depends at which period you want to show her. Colours? various shades of unbleached linin are appropriate and MRP paints are you friend here as they do three shades.

 

Martian 👽

[Chewbacca]

Thanks Martin.  I knew that she was overweight and they took a whole raft of metalwork out to reduce her weight by IIRC 3 tons; I hadn't put two and two together and realised that that was the keel.  Perhaps that would explain then why she broke her back when they moved her out on that fateful day in September 1911.  Given that I plan to portray her on the floating mast when she first came out of the shed, I think I'll go with the earlier configuration and include the keel.

 

And I would would never have thought from the photos that that was unbleached linen but knowing how much research you have done into all things airship, I am very happy to follow your advice.  I should have taken a hint I suppose from the model in the Fleet Air Arm Museum:

 

 

Thanks for all your help

[Paul Lucas]

@Chewbacca,

 

12 hours ago, Martian said:

Colours? various shades of unbleached linin are appropriate and MRP paints are you friend here as they do three shades.

 

Martian 👽

 

According to 'Flight' of 27 May 1911, under the heading 'The Navy Airship No.1 - The 'Mayfly',

"More than an acre and a half of Continental fabric was employed in the construction of the envelope.

...the framework is a covering of fabric, the appearance of which is somewhat distinctive owing to the upper part being silver-grey and the lower half yellow in colour. The upper part is as far as possible a non conductor of heat, and thus minimises the effect of the sun's rays on the expansion of the gas. The lower part on the other hand , is a conductor of heat and thus facilitates the proper equalisation of temperature between the gas and the atmosphere to be carried in a normal manner."

 

In his book 'The British Rigid Airship 1908-1931' Robin Higham states on page 44 that Continental Rubber Company's No.21 fabric, alternating layers of Egyptian cotton and rubber, was made into both the bags and outer cover by Short Brothers. On page 49, Mr Higham writes that 

"The £41,000 experiment, silver grey above and yellow below, appeared to be a success and was so greeted by the press."

He could, of course, have taken this description from the 'Flight' account quoted above.

 

This outer cover was subsequently stripped off and might have been replaced by a silk covering treated with a substance that had the trade name 'Ioco'. This was then painted with aluminium dust. Because this fabric could not be sewn, Shorts developed a 'velure enamel-glue' that was apparently used to apply the fabric to the airframe. 

 

With regard to the gondolas, on p.44 again, Mr Higham wrote that 

"The gondolas, which had to be waterproof and in the form of small boats, were manufactured out of copper-sewn Honduras mahogany by Saunders-Roe of Cowes.

 

I have to admit that looking at the photos I have, I don't see anything resembling what I might think of as being a yellow colour on the underside of the envelope prior to the refit.

 

What I think I see is an overall aluminium finish of uneven colour reminiscent of a natural metal finish.

 

As a footnote, both yellow and an aluminium colour seem to have been fairly common on outer covers of British airships. A War Office recognition diagram of July 1914 gives 'Dull Silver' as the colour of Parseval Airships belonging to the Royal Navy while RN Astra Torres Airships are described as 'Bright Yellow'.

 

 

 

Edited August 22 by Paul Lucas
To add tag.

[Chewbacca]

Thanks Paul.  I suppose a contemporaneous record has to be given a good deal of credence even though i agree with you that it certainly doesn't look two-tone top to bottom.

 

Fortunately (or perhaps more accurately unfortunately) the decision over colour has been pushed right following as Lord Black Adder might have put it, "a visit from Mr C*ck-Up".

 

I was starting to take the highpoints of the filler off before finishing with some 1/600 wet/dry when I noticed that the join between the aftermost straight hull section and the front  tapered tail section had popped open and appeared to be weeping resin.  My only assumption has to be that I didn't give it long enough to cure, but all of the components spent 24 hrs sat on the window sill in the conservatory followed by 30 mins in my wife's UV nail lamp.  That was certainly enough when I did the 1/350 HMS HECLA last year and her hull components were much larger.  I thought I would carry on nonetheless with sanding the rest and within about 30 seconds the aftermost straight section broke off.  So at that point, I gave up and gave all of the parts another 24 hrs in the conservatory in bright sunlight yesterday.  I'm hoping that will be sufficient.

 

 

Thanks for watching

[Chewbacca]

As I said right back in post no 1, I must be mad to think that I could do 2 builds in a GB.  And I was.  I did manage to finish the Lynx with a little under 3 hrs to spare but the cost of that was very little work on Mayfly in the past 3 months.  Didn't help that we were away on holiday for much of October.  I did manage to overcome the uncured resin and bits falling apart, got the hull back together and primed/top coated plus added the keel and painted the gondolas.

 

 

But then Mayfly went no further while I concentrated on the Lynx.  I will continue this over in aircraft WIP and link back to this for the start.  First challenge though is to find what I've done with the gondolas.  They've got to be around somewhere but I'll be blowed if I can find them!

 

I also need to repaint the linen finish.  It seems far too yellow to me.

 

Edited Wednesday at 10:14 PM by Chewbacca

[Chewbacca]

I've started a continuationthread over in Aircraft WIP here: