Overweight condition.....
 

I have a Cermark F-16 ARF.....turned out very nice except that it weighs about 2.5 lbs heavier than its suppose to!! it currently has an O.S. 61 FX on it.....worried it might not take off/fly as well due to its weight......any suggestions???

extra weight
 

There was a fellow that frequented our local hobby dealer that had a similar problem with another plane, that is, it was too heavy. His solution? Cut about 6" off each wing tip to lower the weight.

(OK, it's not the 1st of April...)

Seriously, try to use a long paved runway and keep it on the ground as long as you can. Don't try to force it off the ground. If it does get airborne be very gentle and practice landings up in the air. No violent maneuvers and keep the speed up during final approach.

If it doesn't look like it's ever gonna leave the ground, find a local restaurant that wants to hang it up for decoration and save the engine and radio stuff for another plane

Overweight condition.....
 

2.5 pounds is quite a bit overwheight. Try going over your building process and accessory list to determine where the extra came from.
You could call around to dealers and distributors to help evaluate your setup and the 'normal' flying weight for what you've got in it.
Is your scale fairly accurate? (All things weighed equally the simplest explanation tends to be the right one.)

Pettit had some good advice too.

Good Luck

Overweight condition.....
 

do you think a bigger engine might work?? what about adding a tuned exhaust?

Overweight condition.....
 

The advertised weight for this plane is 7 1/2 pounds. Are you saying that yours came out at 10 pounds? I can't imagine why it would be so heavy. Mine came out at 8 1/2 with a set of SpringAir retracts. It flys nicely on a 61 FX.

More details here: www.bestweb.net/~lieber/flying/f16

--Derek

PS. Did you have to add a lot of tail weight? If so, maybe you could use a lighter spinner instead of the heavy one in the kit. Also, maybe try the first flights without the (rather heavy) belly pan. Did you use a heavy pilot figure? Maybe get rid of that too. Do you have a big battery? Go with a smaller one.

Another thought: are you sure your scale is accurate?
Maybe everything is fine and your scale is wrong?

Overweight condition.....
 

No, I checked and re-checked..........scale is fine. I am going to put a mvvs.77 with tuned pipe in it to compensate for the weight.....should get it off the ground fine.....