The AFB (Amazing FleaBike)

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rtfm

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Jan 3, 2008
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Hi,
I'm having a bit of an issue with URLs at the moment. This is the page address. Checked. I'm not sure where all the other gumph came from. Apologies. I've also added the link to my signature.
Technical resources

I have been checking out my Facebook page, but they are bloody useless. Interspersed with my posts are all sorts of adverts for "bikes" of all sorts. I think I'll just walk away from Facebook as a viable option to disseminate news of the build.
 

rtfm

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Jan 3, 2008
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Brisbane, Australia
Links to the page work. The link on the page to the paper is still dead.
Thanks for the feedback - I'm having an awful trouble getting this to work. It works for me, but not for you (and presumably, not for others). So I have embedded the paper onto the page until I can get this sorted. If you go to the page, instead of a link to download the paper, you will see it displayed. Could you check that the paper is visible to you now?

Thanks for your help.

Duncan
 

Hot Wings

Grumpy Cynic
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It is now accessible.
Click on the little 'full screen' icon on the lower right and then it can be downloaded as a Word file for reading off line.

Way back when I first started messing with web pages I had the same problem of being able to see what I thought was on the web site - but my browser was in fact reading the file from my own computer. That was using Front Page Express. Caused no end of grief for the first few evenings of 'experimenting'.
 

glencessna

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Oct 9, 2015
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PA
<snip>
To get an Idea of just how long ago it was, my daughter is almost 50 years old now. <snip>

Sorry for the off topics but...
Boy you live a dangerous life... I have a daughter “who is almost 40”, will be this year. If I dared to make the almost forty comment she would fly halfway around the world and beat me up. Can’t imagine what she will do when “almost 50”. Lol

View attachment 107148
[/QUOTE]
 

rtfm

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Jan 3, 2008
Messages
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Location
Brisbane, Australia
I've been spending some time yesterday and today (while I wait for my final shipment of plywood to arrive) working on the FleaBike website.

From today, I'll be posting updates and photos here:
Amazing FleaBike Comments

The page includes a sign-up form and a link to my Facebook page (but I haven't yet managed to get the auto-post feature to work).

1612922781734.png

NO SPAM from me, I promise. And no selling of your email address and that sort of thing. Purely me keeping interested folks up to date.

Duncan
 

rtfm

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Joined
Jan 3, 2008
Messages
3,532
Location
Brisbane, Australia
Hi,
I've found a mate who is into building RC planes, and he wants to build the FleaBike. That works out very well for me. It will be most illuminating to see how the double pivoting wings work out.

Oh, and if anyone has tried to access the FleaBike comments/update pages, I spent most of yesterday chasing my tail trying to sort out the bugs. It certainly works for me - so if you'd be so kind as to try the link in my signature and let me know how you get on? I'd really appreciate it.

Regards,
Duncan
 

rtfm

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Jan 3, 2008
Messages
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Location
Brisbane, Australia
Finished the fuselage construction and tail feathers today, and taped the vertical fin on for a photo opportunity.

See build updates via the link in my signature.
 

rtfm

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Hi,
I think I've painted myself into a corner, and need some help/advice on how to get out of it.

1613723022891.png

This is a screenshot of my fin and rudder - and in particular the placement of the rudder horn. I can't remember what I was planning to do for the rudder horn, but this is what I now have. The fin and rudder have both been made, and covered with 1.5mm ply. The red line indicates the rudder cable, and the four holes (I think) were meant to affix a plate on either side, and run a 10mm bolt through the bigger central hole. This was quite a while back, and I can't exactly remember. And (of course) I didn't make any notes. It all seemed simple to me at the time.

Will this work? I mean, a bolt or tube through the hole sticking out 120mm either side. If not, I'm in trouble. Can anyone offer some advice?

Regards,
Duncan
 

TiPi

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a quick answer from a semi-qualified engineer: I would not use a threaded bolt or rod in bending as every thread is a notch waiting to bite into the parent material.
"Easy" way out: make 2 alu sheet angles per side shaped as rudder horns, riveted together and use your 3 holes to bolt them together through the rudder.
 

rtfm

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Hi TiPi,
I wrote a reply, but it was stupid, so I deleted it. Let me think about it some more...

Duncan
 
Last edited:

TiPi

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use alu sheet, not angles. Design your "horn" to the dimensions required (location of rudder cable attach point), make 4.
If make them back-to-back you will be able to bolt them to the rudder and spread the load, while the horn itself is will not twist (no offset). It will also allow you to use thinner sheet.
My CAD program effort :)
Big hole: lose weight
Small holes: 1/8' rivets
You will need to drill some new holes in your rudder as your existing holes don't align with this type of rudder horn.
1613733613656.png
 

Sockmonkey

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Apr 24, 2014
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Flint, Mi, USA
Is the particular rib you're mounting the rudder horn on any thicker than the others?
If not, it seems like a lot of the twisting load needs to be taken up by the skin instead.
 

Victor Bravo

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KWHP, Los Angeles CA, USA
Find a piece of T-shaped extrusion, heavy aluminum or thin steel. Cut two pieces and sandwich the rudder between the pieces. Three small bolts hold the T sections together, sandwiching the rudder. The two horizontal parts of the T have a hole in them for the shear pin for the rudder cables.
 

rtfm

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Jan 3, 2008
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Brisbane, Australia
Hi guys,
Thank you for coming to my rescue with ideas. But what about this:
Forget about the holes already drilled in the rudder. Plug them with dowels and cut them flush - they will be hidden under the paint.

Then move to the bottom of the rudder, where I can bend thin steel to cup the bottom, fold up and place another bend which would be parallel with the wire. Another bent steel piece abuts this.

Like so: The red line indicates the rudder cable, now routed very close to the bottom of the fuselage, with a final pulley placed so that the rudder horn and the wire are in the same plane.

More work, but certainly doable. I like the low profile of the horn vs Victor Bravo's idea, which presents more frontal area (unless I'm mis-reading his suggestion).

1613769882303.png

I also looked into 10mm carbon fibre tubes which could be inserted into the 10mm hole, and bonded in place. It is a better position for the rudder horn, although placing it at the bottom of the rudder is also OK, since the rudder is very torsionally stiff.

A final option might be to use a threaded rod within a 10mm OD sleeve, and thread a nut onto either end to hold the rod firmly against the rudder. Any wear in the sleeve from the threads could be remedied by simply undoing the nuts, and replacing the threaded rod. It will be heavier though than the CF tube.

Duncan
PS Comments welcome, as always.
 

TiPi

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Hi Duncan, I would try to keep the rudder cables as straight as possible.
Another option would be to use your bolt/tube as a spreader bar, run the cables through a hole on each tip and fix them to the rudder further back. That way the tube/rod is in compression, not bending.
 
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