How about a piYak??!! - Page 11 - RC Groups
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Feb 14, 2011, 07:54 AM
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philipa_240sx's Avatar
I have only ever used 3 and 6mm EPP as it's all I can get locally. My 20" NB and piYak are both built from 1.3# 6mm EPP.
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Feb 14, 2011, 08:07 AM
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Rich Wells's Avatar
Quote:
Originally Posted by philipa_240sx
I've been playing with rick.benjamin's drawing as per the DXF File. Just touched it up a bit:

- Rounded all edges so the the curves don't look like multi-sided polygon.
- Added the forward swept elevons (15 deg)
- Rounded the V-stab a bit so it integrates better into the fuse

I'll post the updated drawing as a PDF (tiled of course) once I finish.

Note: DXF can be made available but I am not sure how well the translation will work as I am not using AutoCAD.
DXF format is for document exchange between CAD programs. Thanks for the one you posted.

Rich
Feb 14, 2011, 12:09 PM
flyin' fool
goldguy's Avatar
I've gone from the 1.3# to 1.9# as it's a bit stiffer and more dense. It takes less CF, glue and paint, so that makes up for the slight increase in weight. I use 4, 6 and 9mm, each used according to the size of the airframe.

Wonderful stuff, your foamies will last and last and last.............no matter how you abuse them. And, no waste, just save all the bits and glue them together into bigger pieces as invisible joints are possible.

Since EPP models last longer, the end cost is way less than other foams.
Feb 14, 2011, 12:29 PM
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philipa_240sx's Avatar
Quote:
Originally Posted by goldguy
I've ordered 100 sheets of EPP from rcskyflyer twice, had it mailed and it came right to my door, no duties and no taxes.
If I had 10 close friends all wanting EPP this would work. But for just a few sheets, it's prohibitively expensive to ship.

Thanks for the suggestion anyway goldguy!
Feb 14, 2011, 02:13 PM
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Murman's Avatar
Quote:
Originally Posted by goldguy
I've gone from the 1.3# to 1.9# as it's a bit stiffer and more dense. It takes less CF, glue and paint, so that makes up for the slight increase in weight. I use 4, 6 and 9mm, each used according to the size of the airframe.

Wonderful stuff, your foamies will last and last and last.............no matter how you abuse them. And, no waste, just save all the bits and glue them together into bigger pieces as invisible joints are possible.

Since EPP models last longer, the end cost is way less than other foams.
Thanks GG. I ordered my latest Superfly core out of the 1.3# epp and it doesn't take the abuse as well as the 1.9# Superfly does either. It's lighter, but not by much. I've still got 1.5 bundles of FFF left so I will still build and experiment with that first and when I find a "keeper", I will rebuild with epp.
Feb 14, 2011, 03:38 PM
flyin' fool
goldguy's Avatar
FFF and lots of packing tape is the next best thing. It can really take a joke and when it starts to look sad from the wear and tear, just pour a kettle of boiling water over the blemishes and presto chango.......all will disappear like magic.
Feb 14, 2011, 05:11 PM
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Murman's Avatar
I'll have to remember the boiling water trick. I'm always in a hurry to get my new planes in the air and forget the packing tape part.
Feb 14, 2011, 05:56 PM
Registered User
Also remember to do the boiling water before any gluing of the repair.

This was dollar tree foam I believe before I switched to the superior Hobby Lobby foam core when on sale.

Foam restoration with boiling water (2 min 58 sec)
Feb 19, 2011, 06:05 PM
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philipa_240sx's Avatar
OK, almost there.

Just playing with component placement to get the CG correct.

I've never tried credit card control horns before, but I thought they would be appropriate for this build. I used some Evergreen 0.040" styrene (thanks to the model railroad guys for this stuff) and created a 3" long horn that also acts as a reinforcement for the elevon. Slit the foam and glued in place. Pushrods are 0.060" CF rod with 0.032" wire ends.

I'll post pics later.
Feb 19, 2011, 08:23 PM
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philipa_240sx's Avatar
Quote:
Originally Posted by philipa_240sx
So just a rough calculation:

Airframe: 40g
Motor & prop: 25g
2S lipo: 38g
ESC: 10g with wires & connectors
Servo's: 20g (with wire)
Misc Hardware & pushrods: 15g

Projected AUW: 148g or 5.2oz
Projected wing loading: 2.94oz/sqft
Well, for a change I beat my own estimates!

The final AUW came in at 138g (4.87oz). No paint of course!

The wing loading works out to 2.75oz/sqft

I have to glue the motor mount still. Otherwise she is ready to fly!

Latest photo:
(Gens Ace 2S 450mAh in foreground)
Feb 19, 2011, 10:53 PM
flyin' fool
goldguy's Avatar
Sounds like a winner to me..............
Feb 20, 2011, 08:14 AM
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philipa_240sx's Avatar
Quote:
Originally Posted by goldguy
Sounds like a winner to me..............
Question is: Am I capable of flying it?

I have a lot of left thumb training to do!
Feb 20, 2011, 10:26 AM
flyin' fool
goldguy's Avatar
Only one way to find out..............
Feb 20, 2011, 11:33 AM
Registered User
philipa_240sx's Avatar
goldguy,

Maiden went well. The little Infinite A1705 and 7x3.5 prop has more than enough power to hover. I'm very happy with the choice of motor for this plane. However the pilot needs a lot of practice! I managed a couple of hovers but that's all.

Thanks for the great design guys. Very responsive and fun plane. This will advance my flying skills and provide some much needed practice for my left thumb!


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