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Old Nov 11, 2013, 10:42 AM
Registered User
Oklahoma
Joined Sep 2010
776 Posts
Build Log
Foamie Riser tailless biplane

This little biplane is an addictive blast to fly. It has a wide speed range and will fly very slowly or really scoot. It can be flown in brisk wind, despite the low wing loading. The plane will loop and roll, but its forte is slow flying very close in - indoor is very practical.

Construction is of Dollar Tree foam and all equipment is very economical. Here are the specs:
Wingspan: 26"
Airfoil: KFm-2
Stagger: 2"
Decalage: None
Control: Primary; elevons. Secondary; wingtip draggerons
Motor: 24g, 1300kV blue wonder
Prop: APC 7X5
Thrust line: 0/0
Esc: HK Plush 10
Battery used: 3S 460mAh Nanotech
Servos: HK S0361 (3.6g X 4)
AUW: 10.25oz.
Wing loading: 4.1 oz./ft.sq.

Foamie Riser (2 min 5 sec)


Foamie Riser #2 (1 min 28 sec)
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Old Nov 11, 2013, 10:57 AM
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Crash & Burn's Avatar
Palmdale, Ca
Joined Jul 2004
243 Posts
that flys great. Reminds me of the Sunny box wing, pusher, bi-plane. I built a model of that but didn't get it to fly very well. yours on the other hand is very responsive with a wide speed range. Congratulations. Would love to see a 3 view, or something, of yours that would tell me why mine was such a flop while yours is so good.
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Old Nov 11, 2013, 11:28 AM
Registered User
Oklahoma
Joined Sep 2010
776 Posts
The plane is very easy to build. Attached are drawings generously (and patiently) provided by jbarchuk.

Building should be fairly self-evident. Cut out the main wing pieces (upper and lower are identical,) cut out the KF step layers. Laminate the step layers to the main layers. I use a very thin layer of GG. You can use whatever you prefer. Shape the LE and wrap the LE with a strip of packing tape.

Cut out and laminate the outboard interplane struts (two layers of foam) and the three layers of the center pylon. Cut to length 1/2" light balsa triangle stock fillets and glue them to each side of the top and bottom of the struts and pylon. If you do this on a flat surface, the struts and pylon will automatically be perfectly vertical. I used 15min. epoxy to glue on the fillets so that my patience would allow me to hold the fillets to the struts on the flat surface long enough for the glue to grab. Otherwise, I didn't know how to clamp the fillets to the struts while the glue cured. Note that I beveled the forward end of every fillet to about 45 degrees.

Cut out the elevons (you might as well cut out the draggerons at the same time) and hinge them. I beveled the bottom leading edge of the elevons and hinged them with Blenderm. Install elevon horns (I used horns from a Twisted Hobbies Crack Yak accessory kit that I had extra.) Mount your elevon servos. I cut out the top (step) layer of the lower wing to recess the servos into the wing. With GG it is easy to cut out and peel a recess. I located the elevon servos as far forward as I could without getting so close to the LE that airflow would not be disrupted too much there.

Glue the interplane strut assemblies and the central pylon to the lower wing. The aft edge of the center pylon should be 1" forward from the trailing edge vertex. Glue on the upper wing. The aft edge of the center pylon should be even with the trailing edge vertex of the upper wing. The distance from the trailing edge at the tips from the aft edge of the outboard interplane struts is not critical, but should be the same at each wing tip.

Install the draggerons. Bevel the leading edge of each on the OUTBOARD side of the draggeron; THE DRAGGERONS ONLY MOVE OUTBOARD. You will have to program your radio to accomplish this movement. Hinge the draggerons, install the draggeron servos on the inboard side of each interplane strut. Mount the servos as far forward as possible, as allowed by the forward-end beveling of the fillets. Install draggeron horns and linkages.

Install longitudinal struts (I used 2.5mm CF tubing) under the upper wing, as illustrated in one of the pictures. This is important, as the nose of the upper wing is a weak point with the weight of the battery there.

The motor mount is a simple square of good quality ply, supported on each side by 1/2" triangle stock.

IMPORTANT: I have mentioned several times the need to install things as far forward as possible. I am flying the plane with the 3S 460 batteries, as I have a bunch of them. In order to achieve proper CG (something you absolutely want to do with this plane) I have three U.S. quarters embedded in the upper wing at the nose and one quarter taped to the bottom of the nose of the lower wing. You may well want to use a larger battery rather than adding dead weight. I will tell you that a 3S 1000mAh battery is disastrously too heavy. You will notice the stray section of packing tape on the plane: these are artifacts of CG experiments. Try very hard to get the CG as indicated. The plane will fly with the CG a little farther back, but you will not enjoy it. I presume that a slightly more forward CG might work, but...

The CG indicated on the plans is measured from the nose of the top wing.

I have put some packing tape on the bottom of the lower wing for abrasion protection. For CG reasons, I only did this close to the nose.

NOTE: NEW PLANS BY JBARCHUK ATTACHED (MINOR CORRECTIONS.) THANKS, JIM!
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Old Nov 11, 2013, 11:43 AM
Registered User
Oklahoma
Joined Sep 2010
776 Posts
The plane has been carefully thought out, balancing light weight with strength. If you do anything that makes the plane heavier, it may well break in a less than perfect landing. I have not gone into great detail here, as I presume that someone who can fly this will have some experience building. While this is an easy plane for an intermediate or better to fly, it is not recommended for a beginner. As I believe I stated, it will loop and roll, but I find the most enjoyment out of flying it very, very close in and very low. It really looks neat in the air.
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Old Nov 11, 2013, 11:47 AM
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Palmdale, Ca
Joined Jul 2004
243 Posts
;thanks ombudsman for the info. I think I know now why mine was not very good. I didn't use draggerons on mine even though the Sunny had them. I thought just elevons would do the trick. Otherwise most all of your description is what I had. I may just try this all over again. Again, thank you.
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Old Nov 11, 2013, 11:54 AM
Registered User
Oklahoma
Joined Sep 2010
776 Posts
Quote:
Originally Posted by Crash & Burn View Post
that flys great. Reminds me of the Sunny box wing, pusher, bi-plane. I built a model of that but didn't get it to fly very well. yours on the other hand is very responsive with a wide speed range. Congratulations. Would love to see a 3 view, or something, of yours that would tell me why mine was such a flop while yours is so good.
Thanks C&B. Learning 3D is what I'm into, but I find that this little plane always gets flown every time I go out. As I said, there's just something addictive about cruising it around within touching distance. While it will fly fairly fast, it slows down very quickly with up-elevon and is a piece of cake to catch.

I didn't mention it, but it glides fairly well. It's fun to go up high and fly it down using only using the draggerons - hands-off the right stick.

Dave
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Old Nov 11, 2013, 12:07 PM
Registered User
Oklahoma
Joined Sep 2010
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Quote:
Originally Posted by Crash & Burn View Post
;thanks ombudsman for the info. I think I know now why mine was not very good. I didn't use draggerons on mine even though the Sunny had them. I thought just elevons would do the trick. Otherwise most all of your description is what I had. I may just try this all over again. Again, thank you.
Actually, the draggerons are not at all necessary for flying perfectly satisfactorily. They're mostly for fun. I have my travel on the draggerons set to 100%, but the way I have my linkages set up the travel is insufficient for strong effect. I intend to increase the travel, but just haven't taken the time to do it. Again, the plane flies perfectly well without ever touching the draggerons. I don't think I used them at all in the videos. Incidentally I used channels 4 and 5 on my Futaba 8 Super for the draggerons.
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Old Nov 11, 2013, 12:40 PM
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Oklahoma
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If there are any questions

feel free to post them here or PM me. I'll try to help however I can.

Dave
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Old Nov 11, 2013, 12:52 PM
Slipping the Surly Bonds
dz1sfb's Avatar
Attica, MI
Joined Dec 2006
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Always thought the Easy Riser would make a cool foamie. Though a undercamber reflex airfoil is what the actual craft has. Had one for a short stint.

Ken
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Old Nov 11, 2013, 04:29 PM
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Oklahoma
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Quote:
Originally Posted by dz1sfb View Post
Always thought the Easy Riser would make a cool foamie. Though a undercamber reflex airfoil is what the actual craft has. Had one for a short stint.

Ken
I too had one. Mine was powered by a John Moody (if I remember his name correctly) power system. Tricycle landing gear. I have a couple of pics, but they are escaping me.
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Old Nov 16, 2013, 11:18 AM
just Some Useless Geek
Chicagoland
Joined Oct 2008
2,539 Posts
Ken, is that a ding in the front of the lower main tube of the right wing? Umm...don't you want that straightened out before flying the plane again?
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Old Nov 16, 2013, 04:38 PM
Slipping the Surly Bonds
dz1sfb's Avatar
Attica, MI
Joined Dec 2006
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Quote:
Originally Posted by A Useless Geek View Post
Ken, is that a ding in the front of the lower main tube of the right wing? Umm...don't you want that straightened out before flying the plane again?
It was because of that ding this I parted with this machine. It was getting rashed up.

Ken
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Old Nov 16, 2013, 09:11 PM
SG Talon... Super Genius.
Lenox, Michigan
Joined Nov 2005
3,143 Posts
Ken, Did you really have an Easy Riser??? My Dad was a big Hang Glider hippie back in the 70's. One of the first RC planes i remember him building was an Easy Riser from scratch.

Did you ever finish it and fly it?
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Old Nov 16, 2013, 11:44 PM
Slipping the Surly Bonds
dz1sfb's Avatar
Attica, MI
Joined Dec 2006
10,405 Posts
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Originally Posted by SGTalon View Post
Ken, Did you really have an Easy Riser??? My Dad was a big Hang Glider hippie back in the 70's. One of the first RC planes i remember him building was an Easy Riser from scratch.

Did you ever finish it and fly it?
No I did not Dennis. Had high hopes, but ended up selling it to someone else who had one in the past and was looking for a project.

I do however have a set of plans from which the commercial Easy Riser was developed.

Ken
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Old Nov 28, 2013, 04:37 AM
jclassic1
New Houghton, Derbyshire, UK
Joined May 2006
1,383 Posts
I love my flying wings and also my bi-planes and this is both in one package.It certainly seems to fly bang on and has to be next on my list to build.I noticed you only use the bottom wing for the elvons and it seems to respond well enough but I may fit top elvons as well for even more control.The dragerons or rudders I would call them are needed in my opinion to fly in the wind and help with turning.
Got to order some more 6mm depron before I can get started but it won,t take long to build once I have my foam.

John
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