Couple of Easy Star building tips. - Page 5 - RC Groups
Thread Tools
Apr 24, 2005, 07:39 PM
sargentw's Avatar

Couple building tips

I have a couple of easy, but effective building building tips. However, I have a little background and some experiences from many years ago to share first.

About 40+ years ago, I guess I was around 10 my Pop introduced me to model making. Dad is an avid modeler himself and on top of that an aerodynamic engineer. Well he sat me down at the work shop bench to show me how it was done.... We started with model rockets. Not those ARF ones, these were almost scratch built with templates for cutting the fins. I can't count the number of hours of perfectionist sanding I was put through just to get the fins the right shape/airfoil. Then an equal amount of time was put in sanding off coats of Aerogloss sanding sealer to get the surface smooth as glass.

While working on rockets we started working on hand launch gliders. That was even worse. I'd say Dad isn't this wing smooth enough yet? He would say your getting there but you have to eliminate all the drag that you can. Holy smokes!

Now you can see why I say sand off those mold marks on the wing. Dear old dad. Yes, your model will fly better..... and it has been proven many times in wind tunnels on all types of models that you want the airfoils smooth.

The next couple pictures are of one of Dad's 40+ year old model rockets laying on the EZ. The fins look fairly advanced for 40+ years ago. Imagine that.......

Anyway hope you enjoyed the story. :0
Last edited by sargentw; Apr 24, 2005 at 08:23 PM.
Sign up now
to remove ads between posts
Apr 24, 2005, 07:41 PM
sargentw's Avatar
On this picture you can see I've moved my throw all the way in. I'm glad I reinforced the tail section with a spar. The increased throw really pushes the rudder.

Check out those 40 year old balsa fins. No "turbonator" injection marks on those.
Last edited by sargentw; Apr 25, 2005 at 02:41 PM.
Apr 24, 2005, 07:48 PM
sargentw's Avatar
Ok here is an easy mod for the EZ.

I've noticed that after flying for a while the wings tend to seperate. They have never come all the way out, but I could see a potential problem that needs "nipping" in the bud.

The first pic I have the wings together outside the plane. I'm marking them where I want to put some shallow rout cuts and place velcro. I want the velcro to be strong enough to hold the wings in place, but not too much as to where the wings can't be easily removed.

The gap is about 1/2 "
Last edited by sargentw; Apr 24, 2005 at 08:17 PM.
Apr 24, 2005, 07:51 PM
sargentw's Avatar
Here is a picture where I've made a cut with an exacto. That other mark on the wing is a big bold mark (so I can see it) for the COG.
Apr 24, 2005, 07:54 PM
sargentw's Avatar
You want tape and velcro to really stick to foam, dab on a little 3M-77 adhesive first. It makes all the difference.
Apr 24, 2005, 07:57 PM
sargentw's Avatar
Industrial strength Velcro. I went to BJ's and bought a ton of it. This stuff is really "sticky" and grips like iron. If you need some, PM me and I can arrange to send you some.

BTW those "Gingher" sissors are expensive, but they can cut 1/4" leather like butter. Don't ask me how. They work great for hobbies.
Last edited by sargentw; Apr 25, 2005 at 02:43 PM.
Apr 24, 2005, 08:01 PM
sargentw's Avatar
Here you go the velcro applied. because of the routs the velcro barely touches and the wing ends come together flush. The wings are perfect. No more vibrating out along the spar.
Last edited by sargentw; Apr 24, 2005 at 08:18 PM.
Apr 24, 2005, 08:05 PM
sargentw's Avatar
This is another mod with big drag payback. It takes about 4 minutes to do.

Cover the servo holes on the fuse with clear tape. Here is a picture of a 3M brand I lke.
Apr 24, 2005, 08:08 PM
better than park-n-work
park-n-fly's Avatar
Well done, Sarge. Make sure you reference these mods in the EasyStar mega thread (#18 is the current volume). I enjoy reading your solutions to these EasyStar issues.
Apr 24, 2005, 08:08 PM
sargentw's Avatar
Here is another picture of the servo hole covered. You can barely see it. I cut very small holes around the servo arms. This will prevent the tape from binding the arm and allow air to continue to circulate through the fuse.

That's it for now. Time to get out there and fly.
Apr 24, 2005, 08:45 PM
Proud member of LISF and ESL
Need your help guys!

My friend has one of the new Multiplex Easy Gliders. It is made of the same Elapor foam as the Easy Star and some other Mulitplex planes.

In any case, I was flying it and put it into a tree. I dinged the leading
edge of one wing. Nothing too serious. A depression about the depth of half a
nickel with a small crack in the foam, maybe 1/2 inch deep. Foam was starting to return to shape after sitting about 10 minutes but not all the way back yet.

To restore this foam to shape I heard you pour boiling water over the foam, or dip it in boiling water and the foam returns to its original shape. Is that so? Have you tried it? How much boiling water? How long does it take to happen?

I would presume after you do this you get it all aligned, drizzle in some CA
and it all glues together good as new.

Tell me this is so! Please!
Apr 25, 2005, 06:54 AM
sargentw's Avatar

Some have used boiling water and a spoon to smooth it out. I have not tried it so let us know how the repair goes.

Apr 25, 2005, 08:25 AM
better than park-n-work
park-n-fly's Avatar
Ed, here's a link to Brandie's Elapor Soup Recipe...
Apr 26, 2005, 07:08 PM
sargentw's Avatar
I'm going to post some EZ COG/trim info here because it will help you with the first flight.

Update: 6/3/07 Added some COG measurement and manual pictures.


Update :5/10/08 I now have a high speed 60" wing that is difficult to perform power off test glides. Without a heavy head wind I simply can't throw it fast enough and it noses in because of lack or lift. I have to launch this pylon racer type plane with the motor on. Still the hand toss, where practical is a good final check to make sure the plane will be stable in the air, especially for new flyers.

I wondered about that no unpowered glide tests when first looking at the EZ instruction book. Every other plane I have (except 60" composite wing) I do unpowered glide tests. I started thinking, was it a mistake in the instructions? Is elaptor foam made out of some special formula? Anyway, it's all clear to do unpowered test glides in my book.

I'd make sure the COG is right on the money, this is most important. Don't try to trim out a bad COG with the elevator and think you got it right. Be a master of the hand launch before firing up that motor.

Nose heavy

During the "motor off" test glide if the plane is too nose heavy your COG balance point will move forward. There will be enough lift to carry the plane when first thrown then as the speed decreases the lift decreases and the plane nose drops and speed starts to build again. If you are on low/ground level test glide you will nose in the dirt before the plane recovers (unless you hit a little up elevator so you can bring it in without crashing). In the same situation if you happened to be higher in the air the plane would continue to dive until it picked up speed again, generate lift and start to climb nose up. Then as speed decreased, back into a dive. What you have now is a hard to control roller coaster situation which in the case of a new flyer will cause you to crash, especially when landing.

Tail heavy

During the test glide if your plane is too tail heavy it will go into a stall and the stick controls will have little control and act wacky. My too tail heavy planes simply flip over backwards or veer off left or right flip over and cart wheel. Very ugly. . If you get your tail heavy plane in the air they fly but bounce and jump on very tiny pieces of air. The controls are very wacky and can have sudden unexpected results when flying. Landing is very hard because the controls are dicey and overly sensitive. The new flyers will over control a tail heavy plane and crash because of unexpected behavior. BTW many sailplane pilots move the COG as far back as they can and still be able to control the plane. This makes it easy to watch the plane because it will jump even when it hits the slightest lift. I do this with the EZ as I move the COG back slightly (from 78mm to about 77.5 to 80mm). Makes it a better thermal hunter.

Flying COG check

Not very scientific but works ok to check COG. The plane is trimmed neutral. The COG is on the spar (EZ is measured 78 mm from the leading edge next to the fuse). On a no wind day chop the throttle at 200 ft altitude and put the EZ in a shallow dive, then take your hand "off" the stick. If the plane comes out of a dive and then goes up, you are nose heavy. If the EZ stays in a shallow dive then you are tail heavy. BTW after the tail heavy dive test remember to grab the stick and pull back so you don't crash. If you come out of the shallow dive slowly and return to level flight you got it right.

Hope this helps. Where possible and based on the model design, hand launch and test glide your models before cranking up the motor.

6/12/07 Updates: Added some helpful links lift, drag, cog, etc.
Last edited by sargentw; May 11, 2008 at 09:11 AM.
May 03, 2005, 01:27 PM
Did you get the memo?
BillLumberg's Avatar
Sargent, how did you "apply the tape evenly, and fold the rudder so it goes into the channel" on the rudder? Did you bend the rudder all the way back against the vertical stabilizer and then apply the tape? If so, is there any reason to worry that the "foam hinge" could rip?

Like this:

Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion Sig Four Star 40 ARF Engine recommendations and Building Tips Daverp Beginner Training Area (Fuel) 24 Jul 12, 2009 02:38 PM
Discussion Finished building my easy star :) lee2005 Foamies (Kits) 2 Mar 02, 2007 05:10 PM
Simple 400 Building Tips? 99esq High Performance 4 Sep 10, 2001 07:07 PM
Wattage F-22 Building Tips / Pictures rcfanatic Foamies (Kits) 9 Sep 08, 2001 02:25 PM
IFO Mark3: Any last minute building tips ? volt flyer Parkflyers 13 Jun 21, 2001 03:33 PM