Help.... I just got my AW 540 together and checked the CG. It came in at 2 inches aft of the leading edge instead of 4 inches. I had lightened the LG, placed the battery pack way aft, and lightened the engine box area. It seems like I will need to add 8 oz. at the tail. I haven't read anywhere where putting a YS 91 on the front created this big a CG problem. Any suggestions would be greatly appreciated.
John

Anything in the nose causes a CG problem with this plane. I've seen only a handful truly stock plane postings, most of which used engines in the 20 ounce range. Many of us experimented with servos in the tail for the proper CG. My batt is behind the canopy area installed on a "floor" I constructed between the bottom stringers against a former. The batt is as far back as I could get it based on the length of the lead. I also moved the elevator servo farther rear and built on a box for it (built on to the side of the fuselage.) and used an MK bellcrank to equalize throw. I still ended up with 2 ounces of lead in the tail, but I'm using a 31 ounce Webra 120. Maybe you can do it with no lead. I have no clue what a YS 91 weighs.

This is what happens when you do not do preliminary balancing prior to committing to servo and battery location !!


you obviously do not have dual elevator servos in the rear !! right!!...this would have helped !! I am not fond of dual elevator servos especially when they swing in opposite rotation...but in this case i did it for balancing purposes. While checking my preliminary balance I could see that hanging a 31.5 oz motor on the front would require servos in the rear.

Do not add weight ...this plane is heavy enough as is!!

you need to do one or both of the following.....

1... open the bottom rear of the fuse between two formers and put your battery in there...you can re-cover between the two formers with a piece of white ultracote/monokote....it is not hard... and it looks good enough so you can't even tell....I had to do this also.


2....switch to dual elevator servos in the supplied "optional" location as per the supplemental plans "flying tips" that came with the model.

Did I mention that my plane weighs 8.5 pounds? That's with the 120 Webra (at 31 ounces) and 2 ounces of lead. The servos are no longer in the rear. I had 2 HS 225mgs, but battled with differential throw for far too long. There was no lead with the rear servos. Aerosplat (I think it was) highly recommended the bellcrank, and I agree with him. I used the Aeroglass gear (also brought to my attension by Aerosplat) and Dremeled the guts as much as I thought would still fly safely. At the end it was 8.5 pounds. It flies pretty good at that weight.

The YS91 (only) weighs 24 oz., I believe. Even if I place the battery (800mhr) on the horizontal I need 4 oz. of lead back there to balance at 4 inches. This is absolutely ridiculous. I didn't use the dual elevator servos in the tail and that was a mistake. Thank you for all the helpful replies. I really appreciate it. I may need to put a YS120 on the nose and add another few Oz to the tail. I really hate to raise the wing loading any higher than it is already, though. I might buy a 5 cell pack and at least get some use out of the extra weight. I'll take your advice outssider about the way rearward battery placement. Is there any thing wrong with using a servo extension to extend the battery wire length?
John

battery extension is ok.

I have 120ys (31.5 oz) and dual mini's in the back for the elevators, a micro way up front against the firewall for the throttle and the rudder servo in the rear tray. lots of wood/aluminum removed and the 4v battery about half-way between the elevator and the rear tray. balance dry at 4", tank is close to cg but still a little forward. all up dry weight is 9 lb 3 oz...I don't know how anyone can get much less with a 120 size motor...but...apparently they are !!

ys 91 = close too 27 oz not 24 oz

I would switch to dual servos on elevator in the rear and no added weight...If I were you !!

check the search for edge on this forum,it's been talked to death.
Have a goodun,John.

That's the thing about this plane. The weights are all over the place. I've seen weights from just over 8 pounds to over 10. I cut so much out of this plane, that I take the hatch off at least once during each flying session and have a look. There isn't much left in the front 1/3 of the plane. If I bounce it at all, the hatch comes off again for an inspection. So far I've only lost the gear once, but I expect it will happen again. It flies pretty good now. It's the most pitch responsive plane I've flown that wasn't a fun fly. It's not scarry or twitchy, just responsive. The knife edge could be better, but that's comparing it to my former 120 aerobat which was an Ultimate. It lands nicely. It has a very hard snap. It wish it took less throw to snap, but that (I guess) is what makes it an Edge. The wing just hates to stall. It tumbles well. It's a very good plane, just not quite as good as I expected from AW.