boss351

My Feedback: (6)

I have just put my Great Planes Big Stik (.40 size) on the CG stand, it is modified to be a tail-dragger and has a heavy Rossi R45 motor to pull is along. I have the battery and radio as far back as possible (just in front of the servo mount) and am still finding myself about 1"+ too forward of the recommended CG (3-3/4" from leading edge). Way nose heavy. The engine is mounted with the recommended distance of firewall to prop thrust washer of 4-3/4". I could move the engine back about 1/2" which should improve CG matters a fair bit before adding ballast. Is there something magical about the 4-3/4" spacing to the thrust-washer or would this engine move be ok?
Obviously if I have to add lead weight ballast is it common to cut a hatch in the tail somewhere to install, any better ideas on getting lead back there? As it stands now (without the engine move) I need 3 oz of lead on the elevator to make it balence! So, some ballast will be needed even with the engine moved back somewhat.

I have posted this also in the ARF forum, but on second thoughts I think it belongs here..

Ugo Ferrari

My Feedback: (1)

I simply moved my rudder servo ( Pull-Pull) to the rear and in front of the rudder. C.G was right on !!
Check picture !

boss351

My Feedback: (6)

Hey, I like that idea! I will dry test it at home and see if it adds enough weight, the 3oz of lead back there was not a good omen. I may need to move the engine back aslo a tad, it is the main culprit of the nose heavy situation..

Montague

If there is no cowl, then no, there is nothing magic to the distance from the firewall to the prop.

Well, ok, there is one thing. If the firewall has right and down thrust in it, and it's an arf with the motor mount pre-installed, the mount might be off-center on the firewall so that the engine's crank winds up in the right place at that distance from the firewall. However, for most planes, that's going to be ignoreable, so if it was me, I'd just move the engine back first.

The rudder servo is also a solid idea, of course.

Ugo Ferrari

My Feedback: (1)

Montague is absolutely correct ! I forgot to mention that I also moved my engine back to 4 inches from the thrust washer to the firewall, to achieve the correct CG. I'm flying a Thunder Tiger .46 Pro. CRS on my part....However, I'm allowed, I'm over 70 !! LOL !

Ugo

jucava

Man that servo on the tail looks really nasty, what I did was to put the battery behind the servo tray, this is a fun plane so you may want to go with a 1100mah instead of the 600mah, that also help.

Ugo Ferrari

My Feedback: (1)

Let's face it guys, The Stick is a "Nasty" looking plane ! The rear mounted servo is an easy fix to the problem and is purely functional.( And Accessable)....As is the Stick design.

Ugo

boss351

My Feedback: (6)

Well, the 1/2" move back on the engine got me to almost 3" back from the leading edge of the wing. I am going to buy a 1100 mah battery as suggested above and see if that puts me on the money, if not, then I think it will take very little lead will work and I can avoid the servo mod, last resort...

jucava

Is call Big Stik no Ugly Stick, the Big Stik is beautiful, pay attention to its design is so aerodynamic, with nothing to cause drag, and can be so wild or tame as you want, a beautiful plane, no matter which plane I plan to fly, the Big Stik is always in the car, and ready to fly, too much wind no problem, no wind, no problem, see is a beautiful plane.

boss351

My Feedback: (6)

Well, I couldn't find a 1100 mah rx battery, but I did come across a 1400 mah battery. I finished installing everything with foam etc and put it on the CG machine. Low and behold, bang on the money!! No lead and no mods were necessary! A relief. I agree jucava, this is a beautiful plane, particularly as a taildragger. Can't wait to get it up in the air tomorrow!

Thanks for the help..