Dave Patrick Ultimate Balance question
 

Hello all....
Could anyone please tell me the recomended location of the center of gravity on DP Ultimate 120. I would also be interested to hear any possible changes to that location. I have misplaced my manual and can't get anyone to answer at DP. Please help.....
I have been flying plane with OS160/bison muffler/du-bro mount, 24oz tank, heavy 1900 5 cell pack, and all Hitec digital servos. First of all I'm flying at 6000ft altitude and it makes a big differance in power. The plane flew well and I liked it but even with the big motor vertical was not that great and hovering was not posible and beleive me I tried every prop ....I beleive set up to be to heavy for my tastes so I made a few changes: went to YS120ac and used stock DP motor mount and no muffler saved about 1lb there.16oz tank and lighter battery pack saved another 1lb so I hoping for better performance with the lighter set up but the plane is balancing out about one inch back of where I was with the old set up and I'm not wanting to ad weight.Currently the plane is balancing out at 6" in from the leading edge of the top wing and I think it should be at 51/4".Thanks..............Lou

RE: Dave Patrick Ultimate Balance question
 

From the manual ( I have 2 - don't ask me why [:o]);

" The balance range for the Ultimate is 1-1/2" to 1/2" from the leading edge of the rear cabane - without fuel. "

RE: Dave Patrick Ultimate Balance question
 

Thanks for the info....that puts it right on....will test fly as so as the weather clears

RE: Dave Patrick Ultimate Balance question
 

In the following video the CG is at 1/2" in front of top wing's rear cabane, which is the most aft point per the instruction. With YS 140 DZ, I can only get to this CG when I drop the cowl, wheel pants, use wood prop, light spinner hub, light YS 140 Sport muffler, and add a pilot. Total weight is 12 lb.

http://www.pedrofrigola.com/Ultimate%20Show.wmv

As you can see, it hovers & torque rolls w/ a handful.

Now that I put the wheel pants, cowl, Slimline Pitts muffler, APC 18x8W prop, and 3.5" spinner back on, it's at 13 lb. and balances at 1-1/2" in front of top wing's rear cabane. It looks good now, but performance really suffers.