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Old Oct 25, 2003, 12:05 PM
Registered User
Paso Robles, CA
Joined Jul 2002
96 Posts
Design ideas for an EPP Slope and DS Plank

I have some EPP foam, a hot wire cutter and ideas on construction. Does anyone have suggestions regarding airfoil?

Qualities desired are about 60" wingspan, potential to DS, low drag, high speed, good inverted flight and aerobatics.

Currently, I am flying a Zagi on the slope.

Or is this just not a good idea and the smart thing to do is to purchase a M60, Electron 54, JW60 or Gulp DS?

Thanks, Richard
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Old Oct 25, 2003, 02:06 PM
CaliforniaSailplanes.com
stegre's Avatar
So California
Joined Dec 2002
1,789 Posts
Richard, it is always fun to design your own, but realize that the guys that manufacture kits often go though months of building test models before kitting.

Then after kitting, they refine the design based on feedback from the customers, and in my case the distributor.

My real advice would be to buy one of each, build them, and find the techniques and features that you like the best in order to design your own.

Of course if you can only buy one, The Electron is the best choice. It is fast, durable, aerobatic and fun. I fly mine almost every day.

Steve
http://www.californiasailplanes.com
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Old Oct 25, 2003, 08:18 PM
'sarp 'all
VinceS's Avatar
Canberra - Australia
Joined Mar 2003
336 Posts
I have been looking for a very similar plane myself, and i have chosen the m60. it is faster then the bluto which, from the sound of it, is faster then the electron. Also compared to a JW it is slightly faster.
I'm not sure about the Gulp DS
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Old Oct 25, 2003, 09:34 PM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
27,686 Posts
Not sure where you got your idea of their relative speeds but they're a bit skewed. I'd rank them like this, from slowest to fastest in frontside performance.

JW 54"
Moth 48"
JW 60"
Bluto 48"
Gulp SR quickly followed by
Gulp DS, M60, Electron 54 (all pretty much on par)
Bluto 56"

I own a JW 54, Moth 48, M60, Bluto 48" and Bluto 56". Someone else locally has a JW60 and I base my comparison of the Gulp, M60 and Electron 54 on the results of man on man racing results in California.

M60's been clocked at 116mph on the backside, but that was a *maiden* flight, so it's gotta be
good for more. Electron 54's seen 100ish I think. JW60 apparently's been clocked at 150mph DSing in record setting conditions at Parker by JW himself, but I *know* it's not as fast on the frontside as most of the others.

They all have their relative strengths.
The JW bangs super hard turns and is impervious to turbulence (in other words, designed for DS), and takes plowing straight into the hill at 80mph fairly well.
Moth 48" flits about the sky like a swift on crack, and is probably the fastest 48" foamie at its weight.
Gulp SR is lightweight and fast through turns
Gulp DS is stronger, heavier and fast.
M60 is a great all rounder.. fast, thermals decently, flies inverted well, feels a lot like a glass plane.
Electron 54 looks to be quite strong, fast and a good backside contender. Haven't seen one fly locally yet. Not sure if anyone's actually flown an Electron against an M60 at the same wing loading yet.
Bluto 56 is just outright blazing fast, but doesn't roll or pull turns as well, but it has super energy retention and ballasts up to nearly 60oz internally. Need a foamie for 60mph winds, this is it.

ian
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Last edited by Daemon; Oct 26, 2003 at 12:07 AM.
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Old Oct 25, 2003, 11:45 PM
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markwslope's Avatar
Fontana, CA USA
Joined May 2002
100 Posts
homemade plank

hi richard,

I would also suggest that you get a proven plank kit before building your own. Any of those that Ian mentioned would be fine and would be a good step up in performance from a zagi. You'll learn about the very sensative CG of a plank and about flying faster and conserving your energy.
As far as an airfoil for your own design one of the MH(martin hepperle) series would be good. I believe the gulp uses a modified(thinned) MH45. Also the MH60 series would be great for a plank. I'm not sure but looking the profile on my M60 it's darn close to the MH64.
Good luck
Mark
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Old Oct 26, 2003, 03:28 PM
Slopey wings!!
DuCKy!'s Avatar
Auckland, New Zealand
Joined Oct 2003
114 Posts
ZAGI?????

hell yeah, anything is way better than the zagi...
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Old Oct 27, 2003, 04:58 AM
speedfreek
alkoo's Avatar
Newcastle, Australia
Joined Apr 2003
2,952 Posts
Richard,
I suggest you make a 60" Electron. I just clocked 100mph with my unballasted Electron in 15 knots on its first real DS session!! I reckon a 60" version would kick the M60's butt. Im seriously considering making one myself, unless Norm from Tuffplanes starts producing a 60" version. If he does, Ill be buying one for sure!

Waz
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Old Oct 27, 2003, 08:46 AM
Lifes 2 short, go sloping
colorado @ 5500feet
Joined Sep 2001
1,054 Posts
I did the same thing once I bought an M60...I wanted to design my own and I did. They are very hard to design on your own, the CG is so percise and the airfoil and wing thickness are very critical. After my hours of flight testing I think I am getting closer to a good design, But it really is alot of work to get it just right. If I were to do it again I would have bought a 48" moth and been down with it...but I didn't so now I am on a quest to get my 44" plank flying right, and I am getting closer.
Good luck if you do make your own plank they are alot of fun!

Vince
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