Composite SuperXtra C.G.

[fdo300]

Hi

I need a little help from you guys, Kiwi's superXtra (old style) is on overhaul right now!!!! a little history fist....... 2 servos per elevator and and ZDZ 160 w/regular muffler in front= tail heavy !!!!.

To get the a decent CG for Imac sequence we had to put 4 lb on the engine dome, then if you want to fly 3D another 1/2 lb on the tail wheel and the wing in forward position. We tested it for about 20 flights, Sequence are perfect but 3D, even with the lead on the tailwheel, is terrible.

So we removed all the lead and the CG it's now 150 mm back on the wingtip with the wings on backward position (IMAC). Now sequence are suck and 3D is much better.

Any of you guys who have one of this SuperXtra can give us some info about CG and specially engine/wings/elevator incidences ??

Regards

Fernando Viollier C.
GSA Sales Manager
Tel: (56-2) 7471224
Cel56-9)843-0510
www.giantscaleaviation.com

[wmat7039]

	Quote: Originally Posted by fdo300
	Hi I need a little help from you guys, Kiwi's superXtra (old style) is on overhaul right now!!!! a little history fist....... 2 servos per elevator and and ZDZ 160 w/regular muffler in front= tail heavy !!!!. To get the a decent CG for Imac sequence we had to put 4 lb on the engine dome, then if you want to fly 3D another 1/2 lb on the tail wheel and the wing in forward position. We tested it for about 20 flights, Sequence are perfect but 3D, even with the lead on the tailwheel, is terrible. So we removed all the lead and the CG it's now 150 mm back on the wingtip with the wings on backward position (IMAC). Now sequence are suck and 3D is much better. Any of you guys who have one of this SuperXtra can give us some info about CG and specially engine/wings/elevator incidences ?? Regards Fernando Viollier C. GSA Sales Manager Tel: (56-2) 7471224 Cel56-9)843-0510 www.giantscaleaviation.com

Fernando.... I have been flying IMAC for 3 years in Unlimited with my Super Extra (774 flights)...so I think I should know something about these planes.

The first thing is that the wing & stab incidences have to be set properly. Where the canopy sits, is not actually level with the thrust line but you can go from there.
Start by levelling the aircraft front to back & also side to side. The wing incidence should be (Negative) -0.5° meaning that when the aircraft is showing level on the canopy rail, the wings should be half of a degree negative. From there, measure so that the stabs are + 0.7° or 0.7 of a degree positive to the wings. This will give you what I have on my aircraft.

My wings are in the back position as I did not like how it flew IMAC precision in the front position. My balance point right now with the wings in the back position is 5 3/8" from the leading edge of the wing tip. I fly with a DA 150 & MTW cannister mufflers. I did not have to add any weight up front at all to balance where I am now. I am using a Tru-Turn solid back-plate spinner, but that is the only weight I have up front. I do have only ONE 8611A on each side of the elevator as opposed to the two that you have. Two will definitely require you to put weight in the front, but "4 lbs"????? That seems way out of line to me.

The engine needs up thrust, I think I started at 0.5° (½° up) & added what was needed in very thin shims until I got it where I wanted it.

The power-box batteries are located on the tray right beside the fuel tank, & the ignition battery is up front to the left of the firewall & strapped to the inside of the fuselage.

I am not a 3D expert, but the airplane allows me to do Knife-Edge loops, K/Edge spins, Harrier rolls, Harriers, (semi)T/rolls & quite a bit more stuff with the Super Extra "as is"...without having to move anything at all.

It seems to me that you need to go back to square one & start from scratch to get everything right. It certainly is a great flying airplane.
Wayne
Sew Busy
http://www.sewbusy.com

[cjbravo]

Thanks you very much for the info Imac HQ, tell me with just one servo per stab, do you have any problems at all.

[cjbravo]

Pon tu foto feña...GSA

[wmat7039]

	Quote: Originally Posted by cjbravo
	Thanks you very much for the info Imac HQ, tell me with just one servo per stab, do you have any problems at all.

No...I've never had any problem at all.... I have heard about some pilots who flew their plane at full bore on the horizontal line & lost it due to flutter...but I've never opened my throttle past half on the horizontal.... there is no need to.... so I don't think I'll come across that problem. I also put in some nylon "bearings" on the elevator hinges at the outer ends to take away some of the slop that develops after about 65-75 flights in the phenolic hinges.... after doing that, the slop went away...
Wayne
Sew Busy
http://www.sewbusy.com

[fdo300]

Wayne

We tried to setup the superXtra the way you do it in your but there are some problems:

- With the fuselaje level to 0° on the canopy rail, the elevator are - 1° with the adjuster full positive, we can't move the elevator to + 0.2° to give it the +0.7° compared to the wings.

- To setup the wing at -0.5° the wings incidence adjuster are complete full up.

- With the fuselage at 0° the engine is -2.5° down.

Maybe the canopy rail shape is a little different form yours, how can we determine the exact thrust line of tnis model ???

Regards

Fernando Viollier.

[wmat7039]

	Quote: Originally Posted by fdo300
	Wayne We tried to setup the superXtra the way you do it in your but there are some problems: - With the fuselaje level to 0° on the canopy rail, the elevator are - 1° with the adjuster full positive, we can't move the elevator to + 0.2° to give it the +0.7° compared to the wings. - To setup the wing at -0.5° the wings incidence adjuster are complete full up. - With the fuselage at 0° the engine is -2.5° down. Maybe the canopy rail shape is a little different form yours, how can we determine the exact thrust line of tnis model ??? Regards Fernando Viollier.

Hey Fernando... You cannot determine the EXACT thrust line with how the plane was molded. I don't think the mold was changed other than when the new version was built with the wing tube instead of the wing spars.

I would still keep the wings/stabs where you are now & try it there... You will definitely have to put in up thrust in the engine... As you have it now, when you pull to vertical, the airplane will want to pitch to the belly & you will have to also put in a LOT of up elevator mix with rudder input. Right now, I have (on low rates) 5% up ele mix with right rudder & 4% up ele with left rudder.

Let me know what you experience.
Wayne
Sew Busy
http://www.sewbusy.com

PS....Here is a shot of my Super Extra with Team Jamaica

[cjbravo]

wayne, Thank you very much for the tips, It really help my set up, It onother plane now.

Regards

[wmat7039]

	Quote: Originally Posted by cjbravo
	wayne, Thank you very much for the tips, It really help my set up, It onother plane now. Regards

Glad I was able to help. Safe flying & enjoy!!!
Bye
Wayne
Sew Busy
http://www.sewbusy.com