Help on balance point

goslow · 1 November 2006, 09:06 AM

Hi folks.......

I need some help in determining the correct balance point on my Scratch-A-Plane Nieuport 17 (quarter scale). This is a "sport scale" model which I have tried to adapt to a little more scale appearence. This model was started years ago when working in Indonesia. (to stay out of those bars) Ended up building plane AND bar hopping ! Thats another story....

Stuck out in the boonies, I had to use whatever material was available to me so non aircraft ply and local hardwood was used, all of which pushed up total weight. My original powerplant was a Quadra 34/35 ??? but now have a Zenoah 45 up front. (20 x 10 prop) I am using a bell crank system like the VK Nieuport and have moved the landing gear forward approx 1 inch. Aside from needing to finally paint the top wing, my all up weight (less any fuel) is now 17 lbs.

I think the engine may be a little excess but then hope to fly around at half throttle for more scale speed. My thinking being, would rather have to much grunt to handle all the built in drag inlieu of under powering to start with.Any comments would be appreciated.

Lucky Dog · 2 November 2006, 02:38 PM

Hello goslow,
17lbs is a bit on the heavy side (but you got to do what you go to do right?). We've had a number of guys build these Scratch-A-Plane Nie17s around here and most came in around 14 to 15 lbs. max. With that wing loading, they fly very well with a US41 or G38. Some think a G26 would be adequate as well. They are great flying planes! Ours seemed to fly along well at 1/3 to 1`/2 throttle. I would think that you're going to have to keep up the speed a bit more at that weight. But maybe not.

Balance is as shown on the plans. If you need more clarification, I can check mine when I get home.

Have a look at http://www.bealmear.com/dawn_patrol/nieuport_17.htm

Good luck and stay in touch. Love to see some pics of yours when ready for it's public debut!

papermache · 2 November 2006, 03:49 PM

Lucky,
The 1/4 scale Nieuport 17 from Balsa USA balances at 4" aft of the upper wing leading edge (center).
You normally need a good deal of nose weight in just about any WWI airplane (especially the short-coupled radial types), so the extra engine weight will probably be a good thing - and you should have plenty of power.

papermache

papermache · 2 November 2006, 03:51 PM

sorry, got Lucky & Goslow mixed up.

goslow · 4 November 2006, 08:12 AM

I can us all the help and advice with my first 1/4 scale flying machine. Will go back to the original planes but still think the heavier G45 (vs Quadra) and messing about with the landing gear should change the balance point. I understand that its better to be slightly nose heavy than weighty tail. Will keep you guys advised.

Where can I get a good picture of the N-17 machine gun belt discharge chute. All the pictures I have ever seen show something like a black line down the entire length of the chute. Wonder if empty belts dropped completely off the aircraft or somewhere internally ??

Lucky Dog · 6 November 2006, 11:02 AM

goslow,
I may be stating the obvious here, but don't confuse the recommended CG with where it actually balances. The recommended CG point won't change unless you've altered the relationship of wing, tail or fuse length. Moving the gear forward and using the heavier engine may make it easier to attain that balance with out adding a lot a dead weight.

You are correct that it's better to start out a bit nose heavy. The old adage is "Nose heavy panes don't fly very well, but tail heavy planes don't fly for very long."

For help with the discharge chute, try these two places for starters.

http://mars.ark.com/~mdf/nieuport.html
http://www.bcam.net/hangar%20ac/nieuport17.htm