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Old Feb 11, 2012, 04:59 PM
Radian, Polaris, Mistaken ID.
Baseman's Avatar
Japan (Military)
Joined Nov 2010
384 Posts
Thank You Daedalus! I will let you guys know how it turned out!
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Old Feb 12, 2012, 02:56 AM
Build, Fly, Rebuild!!
Ghost who walks's Avatar
Australia, NSW, Lake Macquarie
Joined Dec 2011
251 Posts
Quote:
Originally Posted by Lockey View Post
Nice looking setup there Ghost

I did it here in Perth but the guy runs them in the east too … http://www.procad.com.au/Data_Return...tname=SketchUp … not cheap BUT it was worth it, I just couldn’t get my head around it, at least now I have a fighting chance

Lockey
Thanks for the info Lockey and for the build comment, I have a way to go before I turn out stuff as neat as you!!
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Old Feb 12, 2012, 03:33 AM
Build, Fly, Rebuild!!
Ghost who walks's Avatar
Australia, NSW, Lake Macquarie
Joined Dec 2011
251 Posts
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Originally Posted by wheelspinner20 View Post
ghost....outstanding work man... love the torque rods...i did my first that way. i used an oversized milk shake/smoothie straw as a conduit and secured below the end of the t-rod pivots. (in the picture it would be above them because its inverted.) absolutely love the stasked servos....make sure that doesnt tax your bec if using only the esc.... ive run small ones that way...but cheap esc are often flakey and overrated by manufaturer.

anyway...nice work. I too extended ply tail support up to the carbon. it has its benefits and drawbacks i will share more on that when im not on my phone!

pat
Thanks for the comments/tips and apologies for delay in reply (getting spare time to post/ build etc is rare these days)
Due to writing an essay on my first post I didn't put all the specs of my build in.
The torque rods are a dubro 1/2 A strip kit from LHS and went in really easy even taking into account that we put them in from underside of wing due to my stuff up.
I am using the exact same tried and proven setup as my brother in-law "Aus" that is a turnigy plush 40 amp sbec esc, Rc Timer 2212/6 2200kv motor and apc 6x4e prop and 16 gauge wire to motor.

"oversized smoothie straw" up their for thinking out side the square necessity is the mother of invention. I had the brass tube laying around for a work related repair and thought mmm I might be able to use that on something one day, so work lost it

Will be interested to here your comments on extended tail support. Regards Ghost
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Old Feb 12, 2012, 03:39 AM
Build, Fly, Rebuild!!
Ghost who walks's Avatar
Australia, NSW, Lake Macquarie
Joined Dec 2011
251 Posts
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Originally Posted by kepa View Post
There are two excellent books for starting with Sketchup, "Google SketchUp For Dummies" and "Google SketchUp The Missing Manual". Now I'm not suggesting that anyone should do anything illegal or immoral, but I believe they might possibly also be available for download with torrent. I wouldn't know anything about it though...

-kepa
Thanks kepa for not giving me the possibly available thing that you don't know anything about.
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Old Feb 12, 2012, 11:09 AM
chronic in training
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L.A. beautiful san fernando valley
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rudder thickness scratchbuild, and rudder durability

hey guys,

doing a scratchbuild.. is the rudder the same thickness as the fin (fin is basically 4 pieces of dollartree foamboard glued together then sanded to proper airfoil) do I follow the same procedure for the rudder? does the rudder have to be reinforced as all as it takes all the load of the plane in the water?

thanks

Gary
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Old Feb 12, 2012, 04:03 PM
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Joined Sep 2006
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Xl cg

D66,

How far behind the step have you been able to push the CG of the XL before it gets too twitchy to fly comfortably?

Regarding the XL becoming a dog to fly with a heavy battery; Basically the 3200's that I put in are nearly 5 years old. The tests I tried the other night show that they are not putting out any more power than the new 2200"s.

Bob
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Old Feb 12, 2012, 04:41 PM
Radian, Polaris, Mistaken ID.
Baseman's Avatar
Japan (Military)
Joined Nov 2010
384 Posts
grfcon,
The rudder is 1 piece of foamboard. I mount mine with a hinge in the center of the Necelle. I have not had to re-enforce one yet. However, you are free to make changes as you see fit. I have read ALOT of this thread, and I don't recall a rudder structural failure.


Quote:
Originally Posted by grfcon View Post
hey guys,

doing a scratchbuild.. is the rudder the same thickness as the fin (fin is basically 4 pieces of dollartree foamboard glued together then sanded to proper airfoil) do I follow the same procedure for the rudder? does the rudder have to be reinforced as all as it takes all the load of the plane in the water?

thanks

Gary
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Old Feb 12, 2012, 06:56 PM
59 years of RC flying
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Canada, ON, Ottawa
Joined Feb 2006
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Quote:
Originally Posted by grfcon View Post
hey guys,

doing a scratchbuild.. is the rudder the same thickness as the fin (fin is basically 4 pieces of dollartree foamboard glued together then sanded to proper airfoil) do I follow the same procedure for the rudder? does the rudder have to be reinforced as all as it takes all the load of the plane in the water?

thanks

Gary
The rudder is one layer of 6mm Depron on the Polaris and two layers on the XL. On the latter, one layer would do structurally but two makes for a nicer transition from the fairly thick fin.

There is very little load on the rudder in the water, as it's only immersed a small distance. More to the point is what happens on land, where the rudder may be pushed sideways if the model skids. I've never seen the rudder break (except in a crash) but the rudder servo can suffer stripped teeth. You may want to consider a metal gear servo.
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Old Feb 12, 2012, 07:02 PM
59 years of RC flying
Daedalus66's Avatar
Canada, ON, Ottawa
Joined Feb 2006
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Quote:
Originally Posted by bob93447 View Post
D66,

How far behind the step have you been able to push the CG of the XL before it gets too twitchy to fly comfortably?

Regarding the XL becoming a dog to fly with a heavy battery; Basically the 3200's that I put in are nearly 5 years old. The tests I tried the other night show that they are not putting out any more power than the new 2200"s.

Bob
I've had it at least 1" behind the step, though I prefer it on the step. I've flown the regular Polaris with the CG about 1.3" behind the step. I don't recommend that (!) as it does develop rather peculiar handling (I was exploring the spin behavior) but I was able to fly it with little difficulty.

I've flown the XL with two 2200 20C batteries on board and it was still very nice.at about 38oz. The idea was to see if two batteries in parallel was a viable setup. I concluded it was but didn't pursue the idea. The problem was not the weight but the nose heaviness and I didn't want to bother redoing the hatch to get the CofG right..
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Old Feb 12, 2012, 08:45 PM
chronic in training
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L.A. beautiful san fernando valley
Joined Nov 2008
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thanks. going to go metal gear on the wing and on the rudder.. got an hitec hs 55 I can use on the elevator.



Quote:
Originally Posted by Daedalus66 View Post
The rudder is one layer of 6mm Depron on the Polaris and two layers on the XL. On the latter, one layer would do structurally but two makes for a nicer transition from the fairly thick fin.

There is very little load on the rudder in the water, as it's only immersed a small distance. More to the point is what happens on land, where the rudder may be pushed sideways if the model skids. I've never seen the rudder break (except in a crash) but the rudder servo can suffer stripped teeth. You may want to consider a metal gear servo.
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Old Feb 12, 2012, 09:27 PM
Home of "Golf Cart Flying"
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Griffin GA
Joined Aug 2008
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Quote:
Very nice! A thought. With the hatch as long as you have, you might consider a pair of magnets at the middle as well. The upper surface curve and the canopy will be generating lift and although good magnets on the aft end are sure to hold it from leaving the airplane it may flex and distort.
Lookin' forward to seeing it completed.
Ted
Thanks Ted,
I added a piece of 3/16 sq spruce to keep the hatch from flexing. Then 2 strong magnets to hold her down.
The Pseudo Antennae gives me a handle to pull it off.
She is Flyable, but I'm probably gonna go ahead and trim and paint after hearing all the horror stories of people loosing orientation with out proper coloration.

Ted; I do have an exit at the rear top of the fuselage for air to escape...


That is a bead of 5 minute epoxy at the wing joint.
I re-painted the tank green for oxygen.
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Old Feb 13, 2012, 12:24 AM
Aussie, Aussie, Aussie!
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Melbourne, Australia
Joined Apr 2009
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Originally Posted by pecanpatch View Post
I re-painted the tank green for oxygen.
How high are you planning on flying! Oxy?
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Old Feb 13, 2012, 01:02 AM
Home of "Golf Cart Flying"
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Griffin GA
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Originally Posted by nrg2go View Post
How high are you planning on flying! Oxy?
Where the air is Rarified
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Old Feb 13, 2012, 07:28 AM
59 years of RC flying
Daedalus66's Avatar
Canada, ON, Ottawa
Joined Feb 2006
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Gluing Depron

Quote:
Originally Posted by pecanpatch View Post
Ok, here is a quick video I did to show one way to use hot glue.

http://youtu.be/so-R3JHANqY
Thanks for that.

I can see how it can work fine for small jobs like the one shown. What I have been unable understand, though, is how, for example, people can glue the bottom on the Polaris with hot melt glue.

Here's how I go about it, using epoxy.

I use a reasonably slow setting epoxy (say 10-15 minute) to give me a few minutes of working time. I mix up the epoxy and then spread it carefully along the edges of the fuselage, making sure I get a uniform film. Then I locate the front end of the bottom on the front bulkhead with a couple of pins and the back end on the step bulkhead also with pins. Then I adjust the alignment of the fuselage sides with the edges of the bottom, using pins. Finally, I use strips of masking tape across the bottom and up the sides to pull the bottom into tight contact with the sides. You can see how this looks in the manual. If there's any glue squeezing out, I wipe it off with isopropyl alcohol.
Then I let things set for a couple of hours. The result is a totally watertight, indestructible joint that gives no difficulty when it comes to sanding the bottom flush with the sides.
Nobody has yet described how this fairly complicated and time-consuming work (maybe five minutes) can be done with hot melt glue.

The alternative I use for some joints is medium or thick (not thin!) foam-safe CA. I spray the accelerator on one side of the joint (in this case the bottom) and run a bead of CA along the other (the edge of the sides). Getting the bead right requires some care, as you want a fully bonded joint without a whole bunch squeezing out. The accelerator is mandatory. The easy way to do it is to spray on a light mist of accelerator on the bottom -- it doesn't matter if it dries (though I wouldn't wait hours).
The bond is not quite instant, but pretty close, so you have to get things aligned the first time. And you have to press the joint firmly together. I apply masking tape on one end, then move along the piece pressing firmly and applying more tape till its done. If necessary, I put in temporary spacers to get the sides to the right curve.
If ever I discover that the joint is not perfect, I wick in some thin foamsafe CA and press well.

Generally, though, I prefer epoxy for the big critical joints, like battery tray, bottom, wing spars, wing-to-fuselage, nacelle, etc. Used sparingly, it's not excessively heavy, though if I were aiming for ultimate lightness, I'd use CA for most joints (or maybe UHU).
The ideal result is that all joints are stronger than the Depron and that there's no glue showing anywhere. I don't usually achieve the latter, but come fairly close.
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Old Feb 13, 2012, 09:12 AM
Row 0, Seat A
G550Ted's Avatar
Savannah, GA
Joined Jan 2008
2,706 Posts
Quote:
Originally Posted by pecanpatch View Post
Thanks Ted,
I added a piece of 3/16 sq spruce to keep the hatch from flexing. Then 2 strong magnets to hold her down.
The Pseudo Antennae gives me a handle to pull it off.
She is Flyable, but I'm probably gonna go ahead and trim and paint after hearing all the horror stories of people loosing orientation with out proper coloration.

Ted; I do have an exit at the rear top of the fuselage for air to escape...

That is a bead of 5 minute epoxy at the wing joint.
I re-painted the tank green for oxygen.
Excellent solutions and execution for all.

Awaiting pics when finished.

Ted
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