Boomerang help
 

Hi Guy's

Just finished an XL and was wondering what is the furthest back you can move the CG. is the main carbon spar too much ?
I have an AMT 280 installed and even with bats , UAT and pump all the way forward it does not balance at the recemended 220mm from the LE.
I realy hate to add balast if I don't have to, any help would be greatly appretiated

Thanks

Ted

RE: Boomerang help
 

Can't answer your question, but I placed twin 5 cell 2400 mah nicads in the nose section, just below the nose tire.

RE: Boomerang help
 

Ted,
I ended up with 250 mm from the leading edge and it flys great.
jef

RE: Boomerang help
 

Ted,
You don't say where your XL is balancing??

I have posted the easy way to check your XL CG position, and here it is again.

With the wheels down, fuel tank empty (UAT can be full) and the hatch off, just lift the fully assembled model by the former directly behind the fuel tank (in front of the turbine).

If it stays level or drops the nose a tad, the CG is fine. If the tail goes down, add more nose weight as far forward as possible. There's plenty of room for it if it's needed.

Alan

RE: Boomerang help
 

Alan
Are you talking about the former just past the front of the engine in the picture?

RE: Boomerang help
 

Depends what picture you're looking at. The former that's about 13" (330mm.) forward of the trailing edge.

RE: Boomerang help
 

Looking at the first picture on the left and refering to the former that's visable at the FOD screen on the engine. Also, you did mean 330mm forward of the trailing edge, correct? Hopefully I'll get a chance to talk with you in Mississippi this weekend, bringing my XL II and a friend with an Intro.

RE: Boomerang help
 

The former that's about 13" (330mm.) forward of the trailing edge.

Apologies. Obviously not the leading edge. I meant the trailing edge because it is straight (not swept back) and at 90 degrees to the centre line. Makes it easy to measure from it.
I've edited the post.
Alan

RE: Boomerang help
 

The Boomer XL is the most forgiving plane for CG errors I have ever seen. I was having a ball with mine in Waco TX last year with the CG at 330 MM from the trailing edge. I had many flights that weekend, all perfect. Near to the end of the flying, I noticed it wasn't quite as locked in on final as usual. It was nothing really significant. It seemed just a tad more sensitive to elevator than it had been. After several flights that way, I was looking over the plane and discovered a 10 oz. chunk of lead that had been in the nose for ballast had worked it's way from the battery compartment in the nose all the way to the tail. It had wedged under the tailcone behind the engine. IT STILL FLEW FINE! This is one amazing airplane. I love mine.

Looking forward to seeing you in Mississippi this weekend.