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PatriciaJB
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Posted: Tue Nov 13th, 2007 02:35 am |
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Hello Everyone,
Here's a sketch of the glide test version of the bat model I'm working on. [ 'Boudica 1']
I'm installing the tail now , when that's done I'll post photo's.
This version has the wings fixed and the tail and hind limbs adjustable, the purpose being to test the glide and pitch stability with the tail and TE in various positions.
This will, no doubt, lead to changes in the design of the fully flapping version [ 'Boudica 2'] which I've already started building.
Cheers,
Patricia
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Flapper Fan
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Posted: Thu Nov 15th, 2007 01:22 am |
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Thanks for the post. What is the span, aspect ratio and overall length?
Grant
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PatriciaJB
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Posted: Thu Nov 15th, 2007 07:54 pm |
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Hi Grant,
Here are some measurements:
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Flapangle
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Posted: Fri Nov 16th, 2007 04:11 pm |
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Hi Patricia,
Good craftmanship! The covering looks taut and smooth. Can you vary the sweep without changing the covering?
Look out Romans!
George
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PatriciaJB
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Posted: Sat Nov 17th, 2007 02:43 am |
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Flapangle wrote: Hi Patricia,
Good craftmanship! The covering looks taut and smooth. Can you vary the sweep without changing the covering?
Look out Romans!
George
Hi George,
It's nice to hear from you again, how's you own project coming along ?
Re: sweep: ..... No, the gliding model has fixed wings with adjustable tail and wing TE [ to isolate the test results of the tail from any other effects] but the flapping model [ Boudica 2] will have full flapping and sweep ability. I'll probably use a modification of the flapping mechanism that I posted in the 'Flapping Mechanisms' thread.
Cheers, Patricia
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PatriciaJB
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Posted: Sun Nov 25th, 2007 10:12 pm |
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Hello Everyone,
The tail rods are now installed, had to use brass tubes instead of carbon since they were the only things that fit !! The extra weight will help to offset the noseheaviness that exists at the moment [ in Boudica 2 I'll pay more attention to CG position and to total weight]. Each tube is attached to a ball joint so they can rotate left, right, up down etc.
Am now waiting for the membrane material to arrive .
Cheers,
Patricia
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TedGM
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Posted: Fri Nov 30th, 2007 03:09 pm |
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Hi Patricia,
Good workmaship you have in your bat model. Do you have a side view picture?
Cheers,
Ted
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PatriciaJB
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Posted: Fri Nov 30th, 2007 03:16 pm |
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Here's a photo of the underside.
The tail membrane material has arrived and I'm now doing experiments with it, will post more on that later.
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PatriciaJB
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Posted: Fri Nov 30th, 2007 03:27 pm |
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Hi Ted,
I'll post a sideview after I've attached the tail membrane.....because the weight of the membrane may mean that I have to trim off some of the plywood aft fuselage and possibly make other changes !
Cheers,
Patricia
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Flapper Fan
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Posted: Fri Nov 30th, 2007 06:49 pm |
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Any discussion of tail membrane material and differences between wing and tail material would be of interest.
If model ends up heavy, and they all do don't they, you might consider some type of teather support for initial tests. I'll make suggestions if necessary.
Grant
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PatriciaJB
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Posted: Fri Nov 30th, 2007 11:39 pm |
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KJELL wrote: Patricia.
If your tail material is too heavy. Why don’t try with natural feather on your test model?
Kjell
Hi Kjell,
The whole purpose of the model is to study membranes and specifically [in this model] to study membranes when used for wings and tail in a bat-like configuration.
Cheers,
Patricia
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PatriciaJB
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Posted: Sat Dec 1st, 2007 01:04 am |
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Flapper Fan wrote: Any discussion of tail membrane material and differences between wing and tail material would be of interest. This is exactly what I'm interested in too !
If model ends up heavy, and they all do don't they, you might consider some type of teather support for initial tests. I'll make suggestions if necessary.
Grant
They certainly do seem to finish up heavy....and always at the wrong end too !
Here's a photo of the membrane material that I'm going to try on the tail. [Smooth-On 'Dragon Skin' silicone molding compound].
http://www.smooth-on.com/d-skin%20brushon.htm
Smooth-On originally developed it for large scale animatronics projects and special effects in the movies, it's now also used for prostheses. Photo shows the stretch properties. Returns to original size with no elongation under normal use. Can be mixed with various compounds to change the properties. Also has good tear strength.
I'm waiting for the adhesive to arrive [ will experiment to see if it will suffice to attach the membrane to the tail rods and blend it into the wing membrane [wing membrane is different ....it's EPP foam....because in this fixed wing version, it doesn't have to stretch like the tail membrane does] In the flapping version [ Boudica 2] I'll experiment with the Dragonskin.
I don't know if the adhesive will work so, in the meantime, I'm installing the Dragonskin on the tail by using narrow pieces cut from a pair of nylons wrapped around the rods and painted with the dragonskin, so that it forms a mechanical bond by going into the weave then installing the edges of the previously cured membrane to the rod and letting the whole thing cure. [Dragonskin sticks to itself so you can apply a new uncured layer to a previously cured layer.]
I want to experiment with plain Dragonskin membranes, then dragonskin with various re-inforcements, actinofibril-like fibres, dragonskin sections blended with other wing membranes etc.
Cheers, Patricia
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 Last edited on Sat Dec 1st, 2007 01:31 am by PatriciaJB
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PatriciaJB
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Posted: Sun Dec 2nd, 2007 09:27 pm |
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Here's a photo of the strips of nylon soaked in Dragonskin installed on the tail rods. This will, I hope, provide a mounting for the dragonskin tail membrane. One of the main problems is finding a way to attach the membrane so that the tail rods won't tear through it when their postion changes and the membrane stretches.
>>>> Grant said...quote.." If model ends up heavy, and they all do don't they, you might consider some type of teather support for initial tests. I'll make suggestions if necessary....Grant" <<<<<
Hi Grant,
It's looking like it will be too heavy !.....I'm interested in your tether idea.
I'm hoping that it will make a decent effort to glide somewhat ....but even if it doesn't, I will have learned quite a bit about membranes and even more about gross weight !
Cheers, Patricia
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 Last edited on Sun Dec 2nd, 2007 09:30 pm by PatriciaJB
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PatriciaJB
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Posted: Tue Dec 4th, 2007 11:54 pm |
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I've attached the previously cured dragonskin membrane to the tail rods with just- mixed dragonskin. This should blend the membrane with the dragonskin/nylon coated tail rods and cure as one piece. When it's cured, I'll trim the membrane and also trim the wing foam then blend the two.
The membrane could also have been formed by making a positive mold underneath the tail rods and the rear fuselage and brushing the uncured dragonskin straight on to that then letting it cure 'in situ'......I'm used to doing that when making molds of my sculpture so I'll probably try that on Boudica 2.
Cheers, Patricia
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PatriciaJB
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Posted: Wed Dec 5th, 2007 03:08 pm |
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I've roughly trimmed the tail membrane and the wing foam, am now figuring out a way to blend the two [ dragonskin doesn't stick to the wing foam]....may have to stitch more nylon strips to the foam then soak in dragonskin]
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 Last edited on Wed Dec 5th, 2007 03:28 pm by PatriciaJB
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