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Bubble Dancer RES


martynk

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Thanks Chris

I had forgotten I had to glass the beam but TBH, I cant see it bursting, its incredibly strong. However, I am not going to risk not doing it. 

The fit of the rods in the Basswood is very snug. I still have to make the Kevlar tubes but I cant see what benefit they will bring. My plan was to add a 3mm cap tube at each end to support the rods (one of the alternative suggestions). However, there is insufficient material left in the block to do this. One thing I will do is to epoxy some 0.007" CF sheet on each side of the joiner blocks. Should add very little additional weight and hopefully lots of strength.

I think one of the reasons that my blocks are too wide is that I have used the metric version of 3/8" imperial diameter rod specified - which is about 0.5mm wider (diameter) at each junction. I do have  a cunning plan though which will involve sanding a 1mm flat at the end of each rod . That should sort it :)

The main spars were actually quite easy. I appreciate that the load distribution is a log function (IIRC) but I have simply split the spar length into quarters and added the extra thickness at 13.5", 9", 4.5" each side of centre - if that makes sense.

Edit: Forgot to mention - I have looked at the Aviators Studio site. Its a nightmare navigating round it (on a tablet) but its very useful..

This is a really interesting build. Lots of problem solving which is what I love doing.. 

Martyn

 

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A little bit more progress. I sorted out the problem with the too wide/deep dihedral blocks. What I hadn't spotted was that the blocks were too long. They actually sit inside a thick end rib rather than butt up to each other. This meant that I could shorten them by 5mm each which then gave me enough 'meat' to sand away the excess depth and they now fit perfectly.

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One of the disadvantages of working off a scale plan rather then a full size plan. It wasn't immediately obvious.

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This shot shows just how little spare wood there is...

Last night, I wrapped the bolt beam with 2 layers of 60gm cloth and epoxied into place between the 2 centre ribs. Also added the remainder of the ribs, using slow set epoxy for the carbon joint and my preferred PVA for the TE joint

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All clamped up and left to harden over night

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The pins that I use are push pins and rather than go through the material, I use them to locate the material. Does far less damage. 

This morning I started cutting the 1/2" balsa webs. Each one is cut individually using a vernier to measure the length and depth and fitted. There are variations between them - especially because the spar tapers in thickness

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Use a vernier depth gauge to get the height..

And just before I start work,  I had managed to cut about 6 webs - each individually numbered. They wont get glued until the top spar is ready to do in - which wont be until after the other panels are built

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And the bolt beam in place with webs

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A bit of a jigsaw puzzle forming here...

More to come..

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It would be crazy not to do so. There are 2 options depending on what you read, either 0.5 or 1.0 degrees. This weekend I am going to build a jig to set the dihedral angle. I'll include a taper to set 0.75 degree for both of the 1st panels out from centre. No arbitration.

 

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Hi Martin,

Not wishing to worry you, but you have gone a little off-piste with the build, if you have already glued down the ribs to the spar and the ribs to the TE. The general method is to glue rib-web-rib-web-rib... etc down onto the spar, add the top spar and then weight down heavily. Once cured, the excess epoxy is trimmed and the spar is gently 'rounded' to avoid damage to the Kevlar wrap. The spar can then be Kevlar tow wrapped reasonably easily, before adding the TE.

Are you still planning on making the Kevlar wrap?

Otherwise, I'm amazed at the speed of progress! My Allegro took months to get done what you have in a couple of weeks - great stuff!

cheers,

Chris

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That's not worrying me a bit. I had spotted the other way of assembling the spar and wing. I just wasn't comfortable with it. I have already sanded the curve (bevel) in the lower spar before it got glued. A good point and one I forgot to mention. The way I am going to do this is to assemble 5 panels with ribs, lower spar and TE. - so I have 2 references to work from. Also helps protect the ribs a bit as well. Next will be those dihedral breaks and joiners then the webs and upper spar, then bind with Kevlar then the sheeting and cap strips. I think that will be ok. When I glued the spar to the ribs last night epoxy was sparingly used and excess wiped away.

It does appear to be coming together quickly but I spent quite a bit of time researching and planning this build. I am now almost totally deaf (misspent youth and middle age) so don't watch any TV or things that normal people do. I haven't kept a detailed build and time log for this but I would guess I am over 50 workshop hours now.

Appreciate your watchful eye by the way. Never built anything quite like this before so any nudges, prompts or gotchas are very well received.

Thanks

Sent from my iPhone using Tapatalk

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Hi Martyn,i think I have an original "plan pack for this model " I will go into the shed after work and look it out ......don,t know much about what I have but feel sure it says bubbledancer in the cardboard tube ....let ya know .....interesting build by the way !

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Hi timbo

If you want to build one then you can take my place in the queue as my BD is well under way now. I wouldn't mind a plan - however, I have got this far and I wouldn't really want to know what I did wrong :)

Entirely up to you and abbof3f

 

 

 

 

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4 minutes ago, Ribs said:

Finally, for the total kitting plan,, the tapered spars are available here:

http://www.cstsales.com/carbon_Laminates_tapered.html

Not as cheap as you might think, once customs duty is paid. Probably someone in the UK can do it, or do as Martin has and make your own!

The C/F spars from CST would cost about 45USD plus 60USD postage (quoted) plus (I guess) about £30.00 import  and handling duty etc. It may take a couple of weeks due to the package size.

To make the spars yourself you need 2 sheets of .014" x 3" x 36" plus one sheet of 0.007" x 3" x 36" from Freeflightsupples (£34.00 plus P&P) that will arrive in 2 days plus a pack of slow setting araldite and a couple of spare evenings. Mike will also sell the Kevlar thread, carbon tows and carbon cloth to make the tail mount.

http://freeflightsupplies.co.uk

 

 

 

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I defo have a mi-flight model products R08

genuine untouched kit ....box is slightly tatty but it,s all there....circa oct,79! 78 inch t-tail

 

 

 

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Not for me thanks but how much do you want for it? Got a couple of Glider Guiders in the club that may be interested. I'll PM you if they are interested

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Hi Martyn, I do know roughly how much the kit is  worth but would be open to offers ....see if they can tempt me to part with it lol.....I have some news on the plan pack for the bubble dancer to ....Inside the cardboard tube is a plan for a 60" bubbledancer by ron Armstrong 1993 ....this has a letter in the pack also from ron himself .....then a glass pod and boom for the same model...,,,,also  instructions for the build of the bubble dancer.all genuine! which I would also possibly part with for the right money ....regards Mark  

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