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Sep 06, 2014, 08:26 PM
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Build Log

SST (Sloper Steve Tribute) ultrabatic wing!


Mini and full size SST
(Dick J) and I have been on a quest to build and fly an ultralight weight sloper to fly on the small berm in front of his house.

We are big fans of the Zupair Zulus and we asked Zack at Zupair.com if he could cut a mini version (30" wing span) in the hopes of achieving that goal. He was very accommodating and sent us some prototype cores. We built a couple and tried them out but ours were too heavy. They fly great mind you but the sink rate wasn't what we needed for such a small slope. We didn't think it was going to be possible till our friend Dan (Leadfeather) showed us the Mini Zulu that he built using some great lightweight building techniques! My mini weighed just a tad over three ounces and Dick 'a was about four. Dan's on the other hand weighed only two!! Needless to say his worked WAY better than ours. Rather than starting over, we asked him about his 48" wing we've seen him flying when we get together. It's very light and aerobatic and performs multiple flips with ease. We asked if he could get us some 30" cores cut so we could try his light building technique on them. He graciously agreed. He had his friend Mike at Fancyfoam.com cut them for us. We now possess the cores.

Dan thinks that we should be able to get them to weigh between 2 1/2 to 3 ounces. I will cover the lightweight building techniques Dan showed us to make these as light as possible Here goes nothing!

Just a quick update; Mike at Fancyfoam.com now has these kits available on his website. They are very reasonably priced and he even has all the radio gear you'll need as well. Check it out; http://www.fancyfoam.com/index.php?m...roducts_id=529
Last edited by Buenperro; Dec 06, 2014 at 02:14 AM. Reason: Updated information on kit availability.
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Sep 06, 2014, 08:35 PM
Carpe Cerevisi
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Sloper Steve history


While I'm waiting for the glue to dry, I thought I'd share a bit of Sloper Steve's history with ultrabatic flying wings. He was waaayyyyyyyy ahead of his time. Check out his SloFly thread from 10 hears ago!

https://www.rcgroups.com/forums/thum...=threadgallery

He did an immense amount of work creating and developing this wing. Some of the innovations that he came up with for the ultralight wing are:

All epp construction; wing, elevons, winglets.
Ultralight wing; I think his 43" wing was about 7 ounces.
Full airfoil elevons/wing
Closed center gap elevons; reduces drag
Symmetric airfoil
Hollow cut airfoil...this is something I think worthy of reexamining.
Many, many other experiments and developments. The thread is in three parts, but it is worth reading his posts to see the genius he really is.

Even his flying style with the wing was ahead of it's time; check out this video:

Slofly All EPP No Spar 3D Plane (0 min 58 sec)
Sep 06, 2014, 08:37 PM
PGR
PGR
Low AltiDude
PGR's Avatar
Hear that noise? It's me drumming my fingos. It's been 9 minutes since you started the build and I'm getting antsy.
Pete
Sep 06, 2014, 08:45 PM
Registered User
Dick J's Avatar
Foam tac takes a little while to set, so the spar can be cut in he he
Sep 06, 2014, 08:51 PM
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Buenperro's Avatar
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Lol! I can't make glue dry any faster!

This wing should fly in very little wind. If it turns out like we hope, we will be flying when others are just wishing they were! Not only flying but doing multi flips!

Dick J, and leadfeather are building one as well. It'll be interesting to see what we end up with....
Sep 06, 2014, 10:28 PM
Fun ain't cheap!
droydx's Avatar
Sloper Steve really was so classic. I flew with him a couple times at Dave's beach round about 2003-4. He was just starting to experiment with electrics, but was still flying ultralight eps wings, that were very aerobatic in the light lift. I was fling some light eps wings that Les Horvath cut for me, super fun, but not as good at inverted maneuvers as Steve's. I remember him being quite modest, somewhat eccentric and kind of shy, but an absolute super pilot with his wings.

Andy
Sep 06, 2014, 11:42 PM
Winging it >
leadfeather's Avatar
Quote:
Originally Posted by Buenperro
While I'm waiting for the glue to dry, I thought I'd share a bit of Sloper Steve's history with ultrabatic flying wings. He was waaayyyyyyyy ahead of his time. Check out his SloFly thread from 10 hears ago!

https://www.rcgroups.com/forums/thum...=threadgallery

He did an immense amount of work creating and developing this wing. Some of the innovations that he came up with for the ultralight wing are:

All epp construction; wing, elevons, winglets.
Ultralight wing; I think his 43" wing was about 7 ounces.
Full airfoil elevons/wing
Closed center gap elevons; reduces drag
Symmetric airfoil
Hollow cut airfoil...this is something I think worthy of reexamining.
Many, many other experiments and developments. The thread is in three parts, but it is worth reading his posts to see the genius he really is.

Even his flying style with the wing was ahead of it's time; check out this video:

https://m.youtube.com/watch?v=6GrO608IvNQ
The Sloper Steve thread is a great read. Hard to believe some of the stuff he was doing so many years ago.

The min Zulu is such fun; especially on small slope. No reason the mini SST shouldn't be great too! Great idea Rob and Dick!!
Sep 07, 2014, 10:22 AM
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Thread OP

Spar


Spar

I put a spar in this morning. The CG I'm told is around 6" from the nose so I installed the .50 x 3.0 mm ribbon spar ahead of that. Sorry I didn't measure the length of it but you can get a good idea from the pictures. I don't think it's that critical. I plan on installing the gear forward of the spar to try and keep from having to add weight to balance.

Here's a quick way to install the spar. I put a small piece of tape in the center of the spar first to aid in keeping the spar centered while pinning it on the wing and for pulling it in and out while test fitting prior to gluing. I then put a pin in the center of the wing where I want the top of my arc and then pin the outside ends making sure I have a nice even arc. I then add a bunch of pins along the outside (See pic). This locks it down so it doesn't shift around while I make my cut. I use an Exacto with a piece of tape to set the depth and carefully make my cut along the inside edge of the spar. I then take a small Phillips screwdriver and run it along the slot several times to open it up so as not to warp the airfoil when installing it. The tape in the center makes it easy to pull in and out till you're satisfied with the fit. I used Foam-Tac for gluing this as well. I like this method as it only takes a few minutes, it works very well and best of all, it's easy. Next up, cutting the elevons.
Sep 07, 2014, 10:25 AM
It's not going to build itself
TRISME's Avatar
Go guys go!
Sep 07, 2014, 10:28 AM
Registered User
Dick J's Avatar
I didnt use as many pins as Rob did BUT my spar when in nicely ! I also painted my spar white before installation !!!
Sep 07, 2014, 10:45 AM
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Quote:
Originally Posted by Dick J
I didnt use as many pins as Rob did BUT my spar when in nicely ! I also painted my spar white before installation !!!
Painted it? Nice! Yours can be the DS version Dick. It's too late for me to do that but it would have definitely made it less visible. Lol! Actually the spar weighs next to nothing. It couldn't hurt.
Sep 07, 2014, 10:47 AM
Registered User
fearfactorfred's Avatar
Oh yeah now you're speaking my language . So cool guys!!! My hero's

Well and so far I think Robs is going to weigh less then Dicks.
Watching with great interest. Good luck guys keep up the good work.
Sep 07, 2014, 10:53 AM
Registered User
Dick J's Avatar
Fred Fred Fred I thought we were friends ?? he he his always weight less then mine BUT usually they fly the same
Sep 07, 2014, 11:08 AM
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fearfactorfred's Avatar
Hehehe it was just obvious since Rob poked a bunch of holes in his and you painted your spar. I only give you guys crap because I love you guys .

Have fun
Sep 07, 2014, 04:56 PM
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Elevons and hinging


The wing is cut in a full airfoil so cutting the elevons out was a snap. Dan and Mike went to great lengths to find the best combination of elevon dimensions to make the mini do multi flips. On the elevon size testing they did, the best results were 1 3/8" root cord elevon, and 2 1/2" to 3" tip cord elevon. I went with the 2 1/2" tip cord elevon on my build.

I measured and made a straight 90 deg cut and then beveled the leading edge of the elevon only to 45 degrees. I'm only concerned with getting full up elevons. I'm not worried about down for now.

I used Foam-Tac to make the hinge. I can't stress enough about how little is needed to get it to work properly. I went over to Dick's house and we did ours at the same time. He was in awe as to how little glue was used. I put just a hair of glue along both sides and then wipped the majority of it off. I immediately connected them to the wing. Even with such a small amount, I still had to do a little bit of sanding in the joint. You want the hinge to be as free as possible so they work easily and smoothly without any binding.

I went ahead and made my winglets from 3 mm 1.3 EPP (all I had was black) and covered them with 1.7 CP. I'm ready for the gear now!


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