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Old Jul 16, 2014, 12:28 PM
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South Africa, GP, Johannesburg
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Shaping pool noodles to form fuselages

Pool noodles make great SPAD fuselages, especially for flying wings or pushers (since they tend to be a bit flexible, I have not yet tried using one in a tractor application). They are cheap, light, easy to construct and double up as a shock absorber.

The nose can be shaped by carving as one would do for any other foam, but the finish tends to be less than smooth. I have heard of folks using a clothes iron to shape EPP, and I assume this could also work for pool noodles - the catch being that the iron is not going to be much use for ironing clothes again

I use a slightly different technique that seems to work well, even for quite complex shapes (i.e. F16 fuselage). The trick is to cut the profile you want on the INSIDE of the noodle and then pinch the resulting 'wedge' together and glue with contact adhesive. This keeps the nice smooth surface finish of the original noodle intact. I usually just do the cutting by eye, but you could use a paper template to be a bit more precise. As with everything, practice makes perfect and its definitely worth practicing on some scraps before cutting your first nose.

Once again, hopefully a schematic and some pictures will make this technique a bit clearer.
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Old Jul 16, 2014, 02:12 PM
Crash Test Dummy
Brunei, Brunei-Muara, Masin
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Use a Teflon iron shield, you can slip it off when you're done and your iron remains pristine.

They are only a few bucks.

http://www.amazon.co.uk/HQ-UNIVERSAL...m/B000PK31XI/2
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Old Jul 16, 2014, 05:23 PM
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Thanks ES. SO simple yet effective!
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Old Jul 26, 2014, 11:17 PM
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FWIW

HERES the maiden video finally of the mini hell on rails

Slapped on a 3s 2200mah
1350kv 100 w motor
9 x 8 prop

AUW WITH 2200 about 510gms

I've made a 2.5mm correx conventional wing with 3 deg dihedral and interestingly this came out as about same weight as the single skin 3mm version.

Will maiden video tht too.

Simple construction. Used epp foam in LE, 3mm corro spar with a fibre rod inserted in flutes at spar and a shorter length in LE

Joiner is a 90mm piece of mdf.

Ailerons are simply the 2.5mm correct wing folded over and crushed and ca
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Last edited by pzanni; Jul 27, 2014 at 12:28 AM. Reason: 9 x 8 prop
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Old Jul 26, 2014, 11:34 PM
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And the video…

Mini Hell on Rails SPAD (1 min 59 sec)
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Old Jul 27, 2014, 06:42 AM
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Nice - it looks like it can fly at a sedate pace suitable for a park, rather than needing to be hauled around at high speed just to remain airborne.

But a 9x8 prop on a 1350KV 100W motor seems very ambitious. I usually pull closer to 200W with a 9x6 at that sort of RPM!
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Old Jul 27, 2014, 07:07 AM
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Quote:
Originally Posted by Extreme Sports View Post
But a 9x8 prop on a 1350KV 100W motor seems very ambitious. I usually pull closer to 200W with a 9x6 at that sort of RPM!
Thanks ES. I know it sounds odd but thats the setup!

I was getting sick of lacklustre performance (or perhaps my planes are just too heavy!) so I've simply been stepping up prop size/pitch to see how these little motors will go. Motor wasn't even warm after 3 min of flight at mostly WOT.

Anyway, will be going with 3s 1300mah and an 8 x 4 prop for the 2.5 mm corro wing.
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Old Sep 02, 2014, 09:04 PM
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Here's a small basic tip that might be useful for smaller planes and pushers especially.

Here in Aus we have a bird/pidgeon deterrent in the form of stainless steel spikes that are bent and attached to long plastic strips.

I've cut a section of this stuff where just two prongs protrude.

I'm using as landing gear for a lightweight pusher.

Retaining some of the original plastic strip makes it easy to attach to plane with the idea that it'll break before the plane does on a heavy landing.

Unsure of wire gauge but similar to piano wire push rod. As I said, only good for the lighter models.
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Old Sep 02, 2014, 09:04 PM
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Old Sep 02, 2014, 09:06 PM
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Quote:
Originally Posted by pzanni View Post
Thanks ES. I know it sounds odd but thats the setup!



I was getting sick of lacklustre performance (or perhaps my planes are just too heavy!) so I've simply been stepping up prop size/pitch to see how these little motors will go. Motor wasn't even warm after 3 min of flight at mostly WOT.



Anyway, will be going with 3s 1300mah and an 8 x 4 prop for the 2.5 mm corro wing.

Lol, I was reading the prop size upside down… indeed you are right, I was using an 8x6
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Old Nov 05, 2014, 04:39 AM
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More on pool noodle noses

I have a number of planes where I have carved and sanded a foam block to create a nice rounded nose (i.e. pusher jets and twins). However, the depron/ polystyrene foam is not nearly as durable as correx and tends to get scuffed, dented and compressed after relatively minor 'accidents'. Also, its a lot of work to carve, sand and paint a replacement depron foam nose block.

I've now successfully made 3 noses by shaping a pool noodle with a clothes iron...not only is this easier (and much faster) than carving from depron, but they are definitely a lot tougher. Plus the practice I've gotten means that each one is better than the last, so maybe they will soon look as good as depron noses.

Here is the basic technique:
1) Cut a slice of pool noodle of the right length and make sure that the end that will glue to the plane is properly flat. I find the easiest way is to simply iron the end flat.
2) Glue the noodle slice to the plane and carve a very rough shape. You want to leave it about 1-2mm oversized all round. Wrap some masking tape around the fuselage so that you don't melt the correx in the next step.
3) Lay a strip of heavy grade aluminium foil over the nose and 'roll' the iron over this strip to shape the nose. The iron should be on a low temp ('silk' on mine) so that it just softens the surface of the noodle, but does not melt it too much. The trick is to make sure that the foil does not move against the noodle and that the iron 'rolls' rather than 'rubs' over the foil. Leave the foil in place for a few seconds...if you try to pull it off too soon it may still stick to the noodle.
4) Continue the above process around the circumference of the nose until you have the shape you want and the nose has been 'melted' flush with the fuselage sides. Keeping the iron flat against the fuselage helps you get a nice transition from the fuse to the nose and not make the curve of the nose too abrupt. My most frequent mistake is to overdo this step and end up melting too much foam, which leaves 'dents' in the nose.
5) First prize is to use a noodle of the colour you want, as most paints don't adhere well to pool noodles. However, so far it seems that Rustoleum spray paints may stick OK...lets see how my latest efforts hold up.

As with all techniques, practice on some noodle scraps first until you are getting results that meet your aspirations.

EDIT: Still searching for a paint that sticks properly....
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Last edited by Extreme Sports; Nov 05, 2014 at 08:07 AM.
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Old Nov 05, 2014, 03:19 PM
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Thanks ES. Another handy tip.

Recently used your first noodle shaping tip to create a protective nose for a mugi glider I made for a family member, with the added benefit that it can be simply removed as skill level increases via Velcro strips.

Works well. Ta
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Old Nov 05, 2014, 03:48 PM
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Maybe Krylon Fusion for Plastic

-= Dave
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Old Nov 23, 2014, 06:36 AM
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Correx parkjets – it can be done!

Recently I’ve been experimenting with building full fuselage pusher prop jets models from correx. There is no shortage of inspiration in the Foamies (Scratchbuilt) and Pusher Prop Jet Models forums, but the big challenge is to end up with an AUW in the same ballpark as the foam models...one of the keys to the parkjets’ performance is low wing loading and high power ratio.

So far I’ve built Steve Shumate’s Polaris and F22 designs plus a Vulcan and F16 of my own design. Although the AUW of the F22 is in the upper range of the foam version (620 - 650g), both F22 and F16 are in fact lighter than my similarly sized foam Gripen, F15 and ‘foam plus pool noodle’ prototype F16 (admittedly none of these were light builds at around 680g). All the correx jets fly well on the same power set up as the foam versions (widely available 2826-2200KV outrunner with 6x4 prop). So it can be done!

For the slight weight penalty, there are numerous advantages:
  1. MUCH improved toughness. In particular the long noses of the jets have a habit of cracking or crunching on bad landings....much less of a problem with correx. Also, the foamies are very prone to hanger rash...once again not a problem with correx.
  2. The wings can be made with a full (albeit thin) airfoil profile. While this probably does not improve flight performance (in fact my tests so far suggest that high-alpha might be penalised), it looks much more realistic.
  3. Most of the foamies start with a ‘box’ design that then requires lots (and I mean lots) of carving and sanding to get a passable rounded fuselage and decent surface finish. Others require more difficult heat forming of the foam to create the curves. Correx is a much better material to form curves and has the smooth surface finish built in.
  4. In many cases the designs can be simplified, replacing joints with folds. My F22 had about half the parts of the original and was built in half the time of my Gripen.
So, while correx will probably never compete with the amazing detail of some of the ‘pimped up’ foam builds of these designs, it provides a viable option for building cheap, simple and tough models that look at least as good and fly as well as the average foam builders’ creations. The posts that follow share some of the techniques that I have been using on my builds. Bear in mind that the common threads in all techniques are
  1. Light weight
  2. Simplicity
  3. Decent finish
Bear in mind that not all parkjets are equally suited to correx construction, so you need to use your judgment to decide which ones to tackle. I highly recommend taking a look at Jetsett44 blog and some of his and the other build threads...the posts that follow will make more sense.
Have fun
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Old Nov 23, 2014, 06:53 AM
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Correx Parkjets 1: The basic ‘integrated wing’ technique

Unlike conventional ‘wing and fuselage’ builds, in most of the parkjet designs the wing and fuselage are integrated and the wing is the basis of the build. This can be easily replicated in correx with a few minor adaptations:
  1. The fuselage can often be integrated into the bottom wing piece, while the top wing pieces are added to this piece and ‘folded’ to form the LE as done on most SPADS
  2. To get a thin profile wing, you need to score and fold the LE more than normal....I use the rounded LE technique discussed in an earlier post. I found it helpful in both builds to use a single foam rib near the root to get the profile I wanted.
  3. Spars are needed since the wing profile is too thin to work as a pure monocoque. 5mm or 6mm CF, GRP or wood dowels are best for spars...anything else is too thick. I’ve used GRP tubes which are about the same weight as wood, but much stiffer. Of course CF would be ideal to save more weight.
  4. The fuselage is built up on top and/or below of this wing/fuselage base in much the same way as in the foamies. Where applicable, I have used scrap 6mm depron for the formers, but more about these later.
  5. On both the F22 and F16 the top surface of the fuselage can be easily and neatly blended into the top wing surface – more detail on this later. The key thing is that folding the wing closed is one of the last construction steps.
  6. I cut holes in the wing base where it was covered by the fuselage in order to save weight. The trick is to cut as much away as you can without reducing the strength of the structure.
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