HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Nov 21, 2012, 09:18 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
Build Log
Radian, full flying stab, flaps and much more

The club that I belong to,Fresno Soaring Society, decided to have a one plane event for the club. Since a couple of guys were heavy into Radians and Dennis has done a lot of research on them , the Radian was chosen. I'm not very big on store bought foamies and to entice me into to this they said that I could modify it anyway I wanted as long as it was something that the average modeler could do. Boy was that dumb!!

First of all let me say that I think it flies fairly well for a foamie.But it has a lot of short comings. But that may be just my opinion.

One of the things that I am fond of is a full flying stab. They fly smoother to me and are easy to pull off for transportation. So that was high on my list.

Some of the many things that I dislike about the Radian is its thick trailing edges. It's not a 3D machine so why have a counter balance on the Rudder? It's an electric glider , the motor shouldn't run long enough to get that hot, so why put a NACA " drag bucket" on the canopy and a " storm drain at the bottom? They could have done a lot better then having the stabs control horn so far out in the breeze and that huge hole to clear everything in the rudder.The push rods are along the sides, half buried in the fuse, but leave grooves producing a lot of drag.

So I attacked all of these and more. Yesterday I made the first flights and was happy to see that she flew much better and smoother! Today she made her first public appearance and was flown by others all, experienced pilots. They said things like this has " Legs" and very " Smooth " and " It climbs like a rocket in a thermal with a little camber"

I'll start the build in a couple of days , but will post a few pictures tonight. Please feel free to ask any question as we go along. I took the pictures with my phone , since its always on me and convenient. So please excuse their quality.

Blue Skies.......................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Sign up now
to remove ads between posts
Old Nov 21, 2012, 09:29 PM
Red Merle ALES
Curtis Suter's Avatar
United States, Mt, Helena
Joined Apr 2002
5,543 Posts
Brilliant on all counts.

Kit bashing, group building, friends etc.....
Curtis Suter is offline Find More Posts by Curtis Suter
RCG Plus Member
Reply With Quote
Old Nov 21, 2012, 11:37 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
It's to bad that Park Zone can't offer the Radian in an " ALES" version! If Sure Flight could make a foam glider 30 years ago with a full flying stab and thinner trailing edges, just think what the Radian could be!

Several years of sand and boat racing taught me one thing, it's the little details that make a winner. If several small changes are made they all add up to a larger change.

So when you build your Radian pay attention to the little things!And a lot of them!

Below are a few, the NACA drag bucket lid, the storm drain cover and some servo covers. Small drag reducing things that contribute to an over all better performing glider

Yes Curtis, this has been a good move with our club! Today after flying we all went to a hamburger place that I've never been to. They make a fantastic chili burger! Another benefit of having good friends!

Blue Skies......................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Last edited by RWCLOUD; Nov 21, 2012 at 11:39 PM. Reason: forgot a word
Reply With Quote
Old Nov 22, 2012, 05:44 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
Before we start, I'd like to give credit to most of my inspiration on this Radian. First to Dennis Smith, a very good friend, who has done a lot of research on the Radian and who helped me out tremendously! Thanks Dennis! Then to Paul Naton for his extremely helpful video which can be found here
http://glidefast.typepad.com/ Thanks Paul!

The Stab: I chose a pivot point of about 35% for the stab, based on my gut feelings! Next I drew out the bellcrank full size. I wanted about an inch from the pivot point to the forward spar which operates the stab. Next I placed a right triangle with its corner on the pivot point and moved ( rotated) it 5/16 of an inch up and down . The upper lines are the forward part of the belcrank and the lower points are where the push rod will connect. To find this I removed the plastic part that hold the stock stab and measured from the center of the slot down to where the push rod would exit.

Then I made the bellcrank from .045 aluminum with .100 carbon rings to help stabilize the 9/32 inch aluminum tube that is used as a pivot bearing. It pivots on a 1 1/4 length of 3/16 inch carbon tube that a 1/8 inch carbon tube will slide through. The front hole is 1/8 inch.

Next I made the 4 halves of the stab from MPF foam, this is similar to Dollar Tree foam but thicker and better. It can be bought here http://www.modelplanefoam.com/ . I think that $tree foam would be a little to thin to use, but Depron should work or Dow Protection board 111. Or you could hot wire the stabs using your favorite airfoils and vacuum bag them, but I tried to keep it simple here!

Next I cut the groves for the 3/16 carbon tubes with a Dremal and 1/4 inch ball. Just draw a line on the foam and follow it free hand. The grove is too big anyway so it doesn't half to be perfect. Cut the spars and pivot from 3/16 carbon and wrap the end of each tube with unwaxed dental floss or Kevlar thread. Also wrap the pivot tube 1/4 on one end only. Now plug each tube with a little piece of foam, and lay a bead of White Gorilla Glue in each grove stopping short of the root ends, lay the tubes in then another bead of GG. Put the 1/8 inch spars in place through the bellcrank to locate the spars.
Now spray the 4 halves with 3M 77 and put the top halves on. Then put a lot of weight on the 2 halves and leave alone overnight, no cheating here!

Next day sand them to a symmetrical generic airfoil. You have a built in center line to follow. Sand the trailing edge down to about 1/32 inch on both sides for a total of 1/16 inch. Next trim the tips and blend in nicely. Cover the halves with New Stuff, Document laminating film. Don't try to cover the tips. Cover these with thin clear packing tape and iron down . I used Econokote to make the red leading edges on mine.

Blue Skies.......................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Old Nov 22, 2012, 11:22 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
Next up is the fuselage. Strip everything from it. Then sand it wet with 400 sandpaper. Next cut the counter balance from the rudder, leaving the rudder in place. Sand the counter balance and top of fin flat and glue the together. I used CA . The fin is still pretty flimsy at this point, so the slot for the elevator is filled with 1/4 inch balsa. Leave space for the pivot bearing and front spar. Use CA here also.

Next remove foam from the leading edge of the fin as in one of the pictures. Fill this with pieces of Balsa as shown. CA and GG are your friends here. After the GG has cured the Fin is stiffer. Mark a center line down the middle and start carving/sanding. Once you get close re mark the center line and make a piece of 1/8 inch balsa to fit the rear of the fin after cutting the rudder off. Glue the balsa on with CA.

Now make 1/32 inch plywood plates to fit from the rear of the fin and just touch the front balsa. Make then 1 /12 inches wide. Drill 2 , 1/4 inch holes for the front slot and cut with an utility knife. drill a 9/32 hole for the pivot point. Cut a slot in the front for a piece of 1/4 inch balsa to go behind the balsa leading edge, leaving room to recess the ply plates beneath the surface and notches in the rear balsa to keep the plates below the surface. Block up the fuse so that the fin is straight , push a piece of 3/16 carbon tube through the pivot holes and dry fit the plates to the sides of the fin. using 2 right triangles to square up the fin , measure each side of the 3/16 tube and make it square to the table. Once everything is square use GG and clamps to glue the plates on.

Once everything is cured, finish sanding and fill low spots with light weight Spackle. Now you can test fit the Stab and admire your work!

More later, and Blue Skies........................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Old Nov 23, 2012, 01:05 AM
I think I'm inverted. Maybe.
acetech09's Avatar
United States, CA, Pacifica
Joined Apr 2012
1,509 Posts
I'm thinking about converting my Radian to full-flying, but have a few questions.

One is that, as far as I know, you hardly use any throw when full-flying, correct? I start to worry about servo resolution at that point. Is that at all an issue?

Two, does the full-flying stab get caught on the ground much when landing or does the combination of the slight raised stab and small deflection not make that an issue?
acetech09 is offline Find More Posts by acetech09
Reply With Quote
Old Nov 23, 2012, 02:31 AM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
The stab only moves 5/16 inch up and down at the leading edge. The stock servo is used with no problems, but the arm is shortened so that the second hole from the center is used. The long arm of the bellcrank combined with the short servo arm and zero play allows for very smooth flying without any expo!

I don't foresee any issue's with landings, never was a problem with other gliders that I've had even when landing in some pretty rough area's.

These tails are quick and easy to build. I think they are much tougher then the vacuum bagged tails that are on my DLG's. I may even start using them on other gliders because they are simple and cheap!

Hope this helps and feel free to ask more questions.

Blue Skies...................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Old Nov 23, 2012, 01:35 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
The Rudder was made next. It also is 2 sheets of MPF foam glued together. It has a chord length approx 13/16 inch longer. The bottom is angled up only slightly from the fuselages bottom. Then it is beveled at the front and tapered toward the TE so that its less then 1/16 inch. I used pinned hinges to secure it to the fin. A new control horn was made from 1/16 inch plywood.

Now that we have a Elevator and a Rudder we need something to operate them. The stock Radian pushrods are pretty skimpy and are a source of unwanted drag. I had in mind that new push rod could do double duty and also stiffen the fusealage..

First up is the Elevator . Since the bellcrank is longer then the old one the channel will need to be relocated slightly. the pushrods consist of 1/8 inch carbon tubes and 1/16 inch carbon rods . The 1/8 inch tubes have the ends wrapped with unwaxed dental floss to prevent splitting. The stock pushrods make quite a curve exiting the servo area and stick out slightly from the fuselage. I inserted the carbon tube in the forward hole and lined it up with the lower hole of the bell crank. Next using an ink pen mark the new path of the channel. Remove the tube and use a sharp knife to make fairly deep cuts along these lines, then come back and hold the knife at about a 50 degree angle and cut 2 wedges from the channel. After that use the carbon tube to dig out remaining foam. the goal here is the have a straight line from the servo to the exit point near the control surface while keep the tube below the surface of the fuselage. Dry fit the tube and install the push rod to see that it will move freely while meeting the servo and bellcrank. After that remove the tube and run masking tape along both sides of the channel. Mist the tube with water and put a hefty bead of GG in the bottom of the channel. I forgot one step, cover both ends of the tube with masking tape to prevent GG from getting in the tube. Insert the tube and push down with a small stick or something disposable . Don't use your fingers, they'll get GG all over the place! Next run another hefty bead of GG along the tube. Then run another strip of masking tape over the pushrod and use T pins in a criss cross pattern push the tube down again. Use pins every few inches. The GG should foam up and cone out of the holes the T pins made. Once the GG has cured, remove the tape and excess GG. Then lightly sand followed by some lightweight Spackle. Re-sand when Spackle is dry. Remove masking tape from tube ends with needle nose pliers. The Rudder side is about the same except it can run in the original channel that has been deepened.

After taping the lower fuselage it became very stiff!

More later and Blue Skies.........................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Old Nov 23, 2012, 07:37 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
Now that we have the rear of the fuselage strengthened let tackle the front end. I inserted 4 Bamboo skewers , 2 on each side much like the pushrod tubes. Why Bamboo? It's mother natures carbon! But it will give rather then snap. One goes about 1/2 inch below the canopy line and the other goes about 1/2 inch above the line of the storm drain. On my fuse the motor mount ws glued on pretty good, until I stalled it and dorked it in! Had to go home , clean everything up , sand the inside of the motor mount , tape everything that I didn't want GG on and used masking tape to hold it in place while curing. Lesson learned, try harder to remove the motor mount and do it only once!

Another area that was of concern to me is the area that the wings plug into. First make 4 full ribs and 1 partial rib from MPF to fit in the wing saddle.Cover the outside ribs with clear packing tape, this will prevent epoxy from sticking to them. Place all 5 ribs into the wing saddle. Next draw a trapezoid 11 inches long and 2 inches at the base and 1 inch at the tip, tape this to a disposable surface and cover with wax paper. Then cut 2 blobs of 1 1/2 ounce glass and a triangle of uni carbon around 4 ounces that is 9X1 inch. Mix up 12 grams of laminating epoxy and lay the first blob over the drawing ,pour a little epoxy on the first blob and spread it around with a used gift card, next put the uni carbon on , wet it out and finally the last blob. Use the gift card to throughly wet out the lay up. Carefully scrape off excess epoxy. Then using a rotary cutter cut through the glass and wax paper the trapezoid that you drew on the paper. Using the wax paper as a carrier place it with the 2 inch base just aft of the canopy line and smooth down. Carefully remove the wax paper. Then starting at the edge of the canopy line wrap pink surveyors tape around the whole fuse like you would a baseball bat, over lapping about 1/2 of the tape. When you've reached the end secure the tape with masking tape. Let this cure in a warm place or hot box for 24 hours at a minimum, before removing the pink tape. Its best to use a new roll and not an old roll like I did that had bent edges! The bent edges stuck to the epoxy however they sanded off easily. Or you could use VCR tape, shinny side down just as well. Because of the carbon pushrod tubes I felt that adding a carbon tube was unnecessary, so I ran a bead of foam safe CA along the fiberglass keel on the bottom. After a through sanding and filling with light weight Spackle, the lower half of the fuse was covered with heavy duty packing tape and ironed down ,the top and fin were covered with Econokote. The fuse now felt very stiff and slick!

More Later and Blue Skies............................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Old Nov 24, 2012, 01:36 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
While the Epoxy above the wing saddle is curing, lets move on to the wings. First wet sand them with 400 sandpaper. Next true up the trailing edge with a sanding block and 400 sandpaper again wet. On my wings, some of the leading edge didn't get quite filled with foam, so I filled in the areas with light weight Spackle. I get the feeling if you did nothing else to these wings other the sanding them that they would fly much better!

I'm not a big fan of fat trailing edges. One of our club members has extended his and there seems to be an improvement. There has been some discussion in our club about reducing A/R and increasing square inches. I'm of the school that thinks increasing Reynolds numbers ,even slightly is better then a slight reduction of A/R. The other thing that we've noticed is that there are different molds for the wings, some have thicker trailing edges than others. My seems to have one of the thinner wings.

To make the trailing edge extension, lay a flexible ruler on the TE and extend it down to the table top. Measure this distance and the height of the TE. Next make a drawing of this triangle and extend the upper line until it is 1/4 inch thick. On mine the distance was 1 1/4 inches. The idea here is to take a strip of MPF foam, 1/4 inch thick and cut, sand it to a taper to match the wing. So next double the 1 1/4 inches to get 2 1/2 inches and cut a strip of MPF foam 2 1/2 inches wide. Mark a center line and cut,sand so the you have a strip that tapers on both sides. I left the thin sides slightly shy of 1/16 inch. Next take the strip and lay one end square with the trailing edge of the wing and make a mark where they intersect. Check this in several areas.My strips were slightly wider at the tips then the roots. Mark a left and right side and cut 2 strips from the 2 1/2 inch piece. These are your new trailing edges. I glued mine on with Beacon Foam Tack.

At the tips , I extended the new trailing edge all the way out. This leaves a triable shaped area at the tip that need filling with some scrap MPF and sanded down to blend everything nice and smooth. While your there and the tips there is a funny step that should be sanded nice and round, to blend in the rest of the tip. It's the little details that count.

Now we cut out the flaps. Paul Naton started his flaps outboard of the root. As have others. I like mine to start at the root. But I don't think it matters much either way. My flaps are 22 X 1 3/4 inch . This puts them into the curve of the wing. My wing is also covered with a combination of " new stuff" clear packing tape and Econokote. The " New stuff " is used on the inner part of the wing as far out as it will go before the wing starts having compound curves. To cover the flaps and keep them the proper shape, lay the flap on top of the wing just ahead of the flap area and iron down the New Stuff on the upper side of the the flap, then flip the wing over and repeat for the bottom.

Next I cut out pockets for the servos and wires. To keep it simple I cut a channel for the wires with my dremal. This channel is covered with new stuff and when ready the servo wire get pushe down the channels.

The flaps have 1/16 inch ply control horns and the linkage is thread rod and 2 clevises. Also simple.

The wing was then covered and HXT 900 servos installed with hot melt glue.

This just about does it for the wings!
More later and Blue Skies.......................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Old Nov 24, 2012, 08:06 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
OK! Lets wrap this puppy up!

The servos need to be moved forward and centered. Dig out foam for the servos , tape them together to make a brick and fill the un used holes with foam from the no longer used rudder.

To make up the pushrods bend a piece of 1/16 music wire 90 degrees and about 1 1/14 inch long, make 2 of these. Then cut 2 pieces of .025 music wire about 1 3/8 inch long. Lay them next to the 1/16 carbon rod and CA them to the rod. Now slip a piece of heatsrink over the wires , run a bead of CA on the wires and use a heat gun to shrink the tubing. To use this move the whisker aside , put the 90 degree bend through the servo horn and slide the whisker over to act as a keeper. Next slide the push rod into the tube . Now screw a clevis on a threaded connector and line up the push rod and clevis so that you know how long to cut the carbon rod. Cut it , slide the connector on the rod with some CA. As an extra precaution slip some heat shrink over the connector and rod, CA and shrink.

The Pivot still needs to be installed. First wrap about 1/4 inch of the 3/16 tube that is about 1 1/4 inch long. CA the wrap. When CA is dry slide the bellcrank on next to the wrap. Take a square piece of clear plastic or shopping bag, cut a small " X" in it and slide up against the bellcrank. We want a nice tight fit here,it protects against GG getting on the bellcrank. Now slide the bellcrank and pivot through the holes of the ply plates. Next install the wings. Now run the long 1/8 inch spar through the pivot bearing and sight along the wings. They should be parallel, if not sand the bottom of the high side. Make sure the tubes are square with the fuse. When satisfied remove the whole assembly and squeeze some GG in the hole. Protect the open hole of the pivot tube with a small piece of foam Make sure everything is square the run a bead of Medium CA around the pivot tube to hold in place while GG is curing. After it cures, wrap the 1/4 inch sticking out with unwaxed dental floss and CA.

Now hook up the servos. On the Elevator side use the second hole from the center. On the rudder side use the third hole. I used hot melt glue to hold the servos in place.

Now put everything back together. Make a foam piece for the Air scoop from foam, color it with a sharpie and make a foam piece with a small scoop facing rewards . Cover this with 2 layers of 3/4 ounce fiberglass and Minnwax Polycrilic . when dry tape it in place.

Mine is balance 3 1/2 inches from the leading edge and has neutral stability when in a dive test, but that where I like it!

Enjoy! And Blue Skies........................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Old Nov 26, 2012, 11:27 AM
Registered User
TrekBiker's Avatar
United States, CA, Granite Bay
Joined Mar 2004
542 Posts
In picture #50 showing the flaps deployed did you face the flap LE with ply?

also, how much wieght did all the mods add?

Steve
TrekBiker is offline Find More Posts by TrekBiker
Reply With Quote
Old Nov 26, 2012, 12:35 PM
Registered User
RWCLOUD's Avatar
Fresno CA
Joined Jul 2006
1,737 Posts
No facing on the flaps! With the combination of New Stuff and heavy duty packing tape the flaps came out fairly stiff. They work great!

I added about 4 ounces. Most of the additional weight is in the wings, which have a lot of New Stuff on them. If you only used clear packing tape and less iron on covering, you might save a couple of ounces. However in light lift it will out climb a stock Radian when a couple of clicks of down flaps are deployed

And then when the wind picks up it out runs a stock Radian, even when they have ballast.

Also I did end up adding nose weight. About an ounce.

Blue Skies.........................Tim
RWCLOUD is offline Find More Posts by RWCLOUD
Reply With Quote
Old Dec 24, 2012, 06:53 PM
hover, glide, fly
Vortex000111's Avatar
Australia
Joined Mar 2012
122 Posts
thanks for this amazing guide, it seems simple enough or even someone like me to follow and do well I have one question though, what is the "new stuff" which you mention a few times? i cant any explanation anywhere for it.

thanks again, merry christams
Vortex
Vortex000111 is offline Find More Posts by Vortex000111
Reply With Quote
Old Dec 24, 2012, 06:57 PM
I think I'm inverted. Maybe.
acetech09's Avatar
United States, CA, Pacifica
Joined Apr 2012
1,509 Posts
"New Stuff" is a nickname for document laminating film.

http://www.alofthobbies.com/new-stuf...ing-films.html

It's pretty good, but I don't know why people call it "New Stuff" since it's been known for quite a while
acetech09 is offline Find More Posts by acetech09
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Full flying stab. Good, Bad or Indifferent? kenh3497 Hand Launch 41 Oct 13, 2012 05:34 PM
Wanted Full flying horizontal stab & mount brs608 Aircraft - Sailplanes (FS/W) 1 Sep 12, 2012 06:55 PM
Sold LightSpeed III DLG - 6 servos, RDS, full flying stab. apex Aircraft - Sailplanes (FS/W) 2 Jul 28, 2012 01:25 PM
Sold Relisted at much lower price! Two MCPX helis and much more! MINT! edge_pilot Aircraft - Electric - Helis (FS/W) 10 Apr 20, 2012 05:21 AM