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Feb 05, 2008, 11:45 PM
Serbia Moderator
molenjin's Avatar
Discussion

My scratch built "STICK" balsa plane


This is the my new balsa project, an aerobatic model for a 400-class brushless motor, 3S battery and 9x6 prop.

I wanted to have a park-flyer capable of performing fast loops and low passes, but solid and easy to build. I wanted it to have ailerons, symmetrical airfoil and modern powertrain.

It all started with balsa sheet sides. I checked the postion of the motor and battery.
The motor is Hang-IT R/C XTRM XTRM 2212/15 (http://www.aussiemodelforum.com/Main...Article&id=441)



The battery shown here is an Align 2S / 1900 mAh, but the one that goes in the model will have three cells, of course.

The picture also shows the plywood firewall (4 mm) and two plywood sides as a protection for the motor. This will be a bit unusual nose shape - closed from three sides, only opened at the bottom. People normally build their "sticks" with motor exposed from all sides.



Now, the wing. It's flat, no V-shape. Altogether I've cut 14 ribs, 4 of them are a bit thicker and will be used for the central section. The airfoil is symmetrical, S8035 14% (another good airfoil is NACA 0015). Using a symmetrical airfoil makes the building a bit more difficult.





Last edited by molenjin; Feb 06, 2008 at 05:32 PM.
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Feb 06, 2008, 12:07 AM
Serbia Moderator
molenjin's Avatar

Central section, Servos


Three E-flite S75 micro servos. They are pretty much the same as Hitec's HS-55. There is a minor issue with these servos, though, the cable makes the installation a bit tricky, especially if you use thicker plywood for mounts. The servo simply does not want to go through. Oh, well...





Here you can see the end of the fuselage and the wing's central section. I used two carbon tubes as spars - very light but very stiff at the same time. The wing will be fixed using nylon bolts. The aileron servos will be mounted upside-down.





Last edited by molenjin; Feb 06, 2008 at 12:13 AM.
Feb 06, 2008, 12:26 AM
Suspended Account
Wow.... you do nice work!!!

Chuck
Feb 06, 2008, 11:37 AM
GDR
GDR
Registered User
More pics please...

I just completed my own scratch stick so this is very interresting to me. Mine is not nearly as pretty and cleanly built as yours.

What are your dimensions?

Mine is a true stick fuse (I used the stongest peice of balsa I could find-light but fragile.)
30" x 8 1/2" wing (ailerons 2"). Flat bottom airfoil. I used 10 ribs instead of your 14 and wood dowels instead of your carbon. I was going for cheap and easy on this one.

I have not maidened mine yet but I'm hoping for good slow performance w/ a very "lifty" wing that lets me do low speed rolls and such with a 2 cell battery.

Please keep us updated.
Feb 06, 2008, 05:22 PM
Serbia Moderator
molenjin's Avatar
Hello NoFlyZone & GDR, thank you for your comments!

>I have not maidened mine yet but I'm hoping for good slow performance w/ a very
>"lifty" wing that lets me do low speed rolls and such with a 2 cell battery.

Might be good, but I still think this sort of model screams for power, so a 3S battery is necessary.
I fly my "Robina" e-glider: http://www.aussiemodelforum.com/Main...Article&id=405 on a 2S battery, and it's not bad, but, again, not much better than a Speed 400 with Nicads. 2S is only good, IMHO, for very small or indoor models.

>What are your dimensions?

I will soon post a scheme with all important dimensions. At this stage, I can say that the wing span is about 96cm and projected weight would be 500g (50% for the airframe, 50% for motor, battery & RC).

Cheers,
Miroslav, Brisbane
Feb 06, 2008, 08:57 PM
Registered User
AmateurE's Avatar
Miroslav, my word, congratulations, that has got to be the cleanest model in progress and work area I have ever seen. The wood, the cuts, and the joinery look excellent. Where is the traditional piles of tools that slowly will occupy every square inch (or centimeter) of work space? Let alone all the sawdust, random bits and pieces of balsa, the blood splatters from Xacto blades gone wild and the traditional thumbprint on the fuselage that happens when thin CA meets skin. Looking forward to the build. Excellent work!
Feb 06, 2008, 10:19 PM
Serbia Moderator
molenjin's Avatar
>..that has got to be the cleanest model in progress and work area I have ever seen.

Well... my garage and my work table is a pigsty, like any one else's, I guess ..



But when I need to make photos of the current progress, I do it on my car's trunk:

Last edited by molenjin; Feb 06, 2008 at 10:24 PM.
Feb 07, 2008, 01:15 PM
GDR
GDR
Registered User
I still can't get over how clean your wing ribs are. How do you cut/shape them? I stack mine like you did then shape them on a belt sander. Works well and it's fast and easy.

I maidened mine today and I was very pleased. Did exactly what I had hoped. Flew and was controllable at a walking pace. At full throttle it could climb ALMOST verticle from level flight (I used a 11/4.5 " prop). If I did a dive to get a little extra speed I could do some nice verticle rolls. The big ailerons really helped it do very quick horrizontal rolls at slow/medium speed. This is just what I was shooting for, now I have something to fly my stupid 2cell batteries with and still have fun. This was my first attempt at scratch building so I'm thrilled the thing got off the ground at all.

Can't wait to see your final product.
Feb 07, 2008, 01:20 PM
Promoting Model Aviation...
Murocflyer's Avatar
I agree. Great work. Following closely.

Frank
Feb 07, 2008, 07:35 PM
Registered User
oldschoolvdub's Avatar
You're quite the photographer also. Very nice...
Feb 08, 2008, 12:29 AM
Registered User
It's great to see a quality, hand-cut balsa build. Great work. Thanks for sharing.
Feb 08, 2008, 08:00 PM
Registered User
Good work!
Feb 08, 2008, 08:10 PM
Serbia Moderator
molenjin's Avatar
>Can't wait to see your final product.

Me too.

But with a full-time job and three kids, it does not go that fast...











Feb 08, 2008, 09:15 PM
Registered User
That is just awesome craftsmanship!!

Looks heavy, what's it weighing like that?
Feb 08, 2008, 10:09 PM
Crash happens! :)
.....
Last edited by Arrow; Apr 13, 2008 at 02:26 AM.


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