Here is a list of all the postings Stefan Hafner has made in our forums. Click on a thread name to jump to the thread.
|Thread: Foam Wing manufacturers|
foamwings.co.uk had a few wings from him now and always very happy with them
- edit just saw he's stopped making wings, guess i'll be looking for a new place too then
Edited By Stefan Hafner on 03/01/2017 15:22:14
|Thread: Gliding video thread|
|Thread: Flying club near Banff, Aberdeenshire, Scotland|
Dallachy aeromodellers used to be near spey bay, used to fly there till I moved down south
|Thread: Own Design Aerobatic Aeroplane|
Looks good CS, I'd agree with David, 2 servos are the way to go if you want to go for aerobatics, it'll give you the freedom to add differential and other mixes too.
You'll find the Edge style wing will be less prone to tip stalling as it is effectively a forward swept wing, but if you're not using too much of a taper that won;t cause any major issues anyway.
|Thread: And now for something completely different....in Depron|
Looks interesting Simon, I've been tempted to do something similar but bigger, when my wallet allows me
Regarding stability, what about simply having the batteries mounted lower down the fuselage if you have any problems, may improve things somewhat?
Interestingly, I read somewhere that the reason for the anhedral was that the original design was too stable so to compensate they added the anhedral.
|Thread: 1/3 Scale Sopwith Triplane|
This looks superb, will be watching with interest
|Thread: Anyone cut custom wing ribs?|
If you wanted go down the foam road (no pun intended), have a look at **LINK** for cutting wings, he did a set for me a few years back, that were spot on, and good price too. I finished them almost as described in my post above but with balsa and glass instead of ply and carbon. I did it by laminating on the first layer of glass and cloth and balsa then just putting the core back in the outer shells and applying lots of weight, then added the leading edge and glassed over the whole lot and sanded. Crashed the plane recently and broke the fuselage in 5 places but the wing just had some minor scratches, and I would guess that wing cost me about £60 in total.
Don't forget to add some hard points for attaching the wing though, as the foam itself is weak, couple of aluminium plated bonded into the foam top and bottom with a hardwood space would be ideal, the you can just bolt straight through
I did suspect it was for a car from the pic above
Are you talking about making from a solid piece of wood or as a built up wing?
Personally i think you'd be better with a foam cored wing with a hardwood leading edge and an aluminium trailing edge.Then fibreglass the whole lot. Cobbled together a quick ProE model to give you some idea of what I mean.
I think this would be more ding resistant than a built up wing, as you could use blue foam or even pink foam for the core, these will give a core that will spring back to the original shape, where as a wooden wing will just crack. The aluminium sheet could easily be filed down to give the correct shape for the TE and will give a harder edge, or if you have the facilities you could lay it up on carbon before bonding it to the core.
If you want something really strong and you have access to vac bagging gear, the you can make a really strong one. If you take the same core with the carbon TE, then apply a layer or carbon cloth, then add a sheet of 1mm birch ply over that, then another layer of carbon cloth, and shove the whole lot in a vac bag till its cured, hey presto, super strong but light wing
Edited By Stefan Hafner on 30/04/2014 14:56:54
We built a wing using the S1223 while at uni a few years back for the BMFA Heavy Lift. The railing edges were a bit of a puzzle to work out at first, but we ended up using balsa and glass to give them strength. We started by making a foam template that gave the correct underside profile, then added the ribs and the top skin, then weighted down the whole thing till it was dry. Then we simply sanded the trailing edge to shape and added a layer of glass cloth to the top and bottom to give more strength, applied with epoxy.
|Thread: C of G calc confusion.....|
As long as you set the sweep value (S on the calculator) to zero the CoG will be correct. I'm guessing you could even use a negative in as the S value to calculate a forward swept wing, assuming the script could handle it.
You're right in saying that the CoG calculations don't take into account, they are only geometric solutions to find the neutral point, and then you choose your static margin to find your centre of gravity, as the static margin will determine how stable your plane is, the bigger it is the more stable the plane will be.
|Thread: 150% Seduction Freestyle Build|
Well, after having gone to the field yesterday only to find a fairly stiff crosswind that i didn't fancy doing a maiden in, today dawned flat calm with sunny blue skies, so off to the field again i went.
And the good news is, She Flies !!!! looks like plenty of power and after a few clicks of trim she flies like on rails. Had a very nice flight, then went for a second one, where the engine cut on me just after take off, so put her down in the neighbouring field, no damage don, but the a bit of soil got into the carb so decided to leave at that and clean out the carb properly at home, better to be safe than ruin the engine. pretty sure she was just running a bit too rich and is still bit fussy as its only had about 3 tanks of fuel through.
And here, a few pics (screen caps from the video)
Will get a wee video made over the next few days
Ran the engine in earlier, oh the lovely oily mess but what a lot of power, certainly not going to be lacking in that department
Annoyingly the battery I was planning on using for it was pretty dead, and no amount of cycling it would bring it back to life, so new one ordered, but means the maiden flight is delayed
Cheers guys, hopefully get the maiden in the next week or so,
Sadly its not always sunny out here, got absolutely soaked this morning while we built a satge for a wee music festival we organise every year
Got all the major assemble finished now, just got to finish up the electrics and run in the engine then shes ready for flight
Well, its almost there now, after delays with making the canopy due to not being able to get the right materials out here in rural Spain, I've almost finished the canopy now, just need to spend a bit more time sanding and lacquering, then pop on the canopy and some trim lines and it as good as ready to go, fingers crossed I'll have it done this week
|Thread: 1/4 Scale Twin Turbine A10|
Thats certainly a good size, what scale are you building it at?
|Thread: Carbon vs Glass|
Repairs are much the same, you can use glass or carbon cloth exactly the same way so easy enough to do.
Stiffness is only one part of the story, carbon is much lighter, so impact will have a less momentum behind them. As RGP says, either will break in a proper crash.
Remember, carbon is a superb RF shield so 35mhz needs the aerial outside the airframe. Not a problem with 2.4 though
Personally I'd go for carbon, even if it is more expensive, just looks so cool too
|Thread: 1/4 Scale Twin Turbine A10|
Love the A-10, will be watching
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