(2720 - 3180g)

when does it start becoming a problem when going over the flying weight limit?... will the power of the motor make a diff?... from you guys experience what is the max weight possible to go over before the plane is impossible to fly?...

Max weight is hard to say without some details on the plane. Wing design and position can make a lot of difference. You can overpower all day long, but if you get too high a wing loading then you end up with a flying brick. With higher weight comes longer takeoffs, faster landings, and higher stall speeds. You also have to look at the higher stresses on the airframe.

I am all about overpowering planes for fun, but sometimes you have to take the bad with the good. Give us some more specifics on the plane and the engine and someone can point you in the right direction.

well I have a Rossi R65 2stroke that weighs 610g without muffler... the plane I am referring too is a GP Revolver... Wing Loading: 25 - 29 oz/sq ft (76 - 88 g/sq dm)... I have no clue what that means...

Just going over the max recommended won't suddenly create a deadly creature if you just go a bit over.

Tower recommends up to a .55 engine for the Revolver. Figure the OS.55AX is 18.5oz with muffler and your engine is???

Go much over on the power plant weight and you'll need to move the battery back and maybe a servo or two (if you can) to keep the CG where recommended without adding more dead weight. The important thing is to keep the CG at the recommended location.

That model is pretty fast with a 46 on it. So adding some weight isn't going to turn it into a completely different animal.

Just try not to go over 1.5X the wing loading and keep the CG where it's supposed to be.

The CG is a bit more important with heavier than recommended models. Moving a CG forward (weight or not) reduces the tail's effectiveness. Make the plane heavier and that forward CG can defeat the tail that's already had some power taken away.

I once had a 40-size P-51 with an overly heavy engine. I had to add a considerable amount of lead to the tail to compensate.

The plane flew great. The extra weight didn't bother it a bit.

However...

Landing the plane was damn-near impossible. The landing gear were raked forward and had a coil in the struts. Landings were a series of bounces due to the excess weight.

So different loads will affect different planes differently

Lighter flies better. That's why they made the real planes out of aluminum and not steel.

The airfoil and wing shape can make a huge difference in how a model carries additional weight. True, you can make a tree stump fly with enough engine and prop . . . but it will fly like a tree stump. It will be less maneuverable (in extreme cases fun things like trying to pull up from a dive and continuing the same heading but with stalled wings - SMACKO!) As far as I know there is no standard or rule-of-thumb for safe weigh ranges. At some point you'll just have a miserable to fly model that won't be controlable and the problem solves itself. I've seen models fold up in flight when the weight and stresses of over-powering the airframe show themselves. A crowd pleaser, but expensive for the pilot.

In the case of the Revolver I'd say you'd have a good sport/stunt plane with a .50 size engine but more of a pylon racer with a .65 Rossi. Flyable and fast but probably a handful to land. You may need to add tail weight to balance the heavier engine - adding even more wing loading. A 21.5 oz engine without muffler vs., say, a Thunder Tiger Pro-46 at 17 oz with muffler seems like a big penalty in weight.

When you get heavy it takes more speed to make the same lift to get off the ground. This often means a bigger engine. This all means even more weight. This adds more stress to the wings. If you want the wings to stay together then you need to beef them up - more weight and the eng may change the CG. Change the CG and you need more weight to balance the plane. Now the plane is a brick. Bricks don't fly well. Bricks need a lot of speed to land well (at best). Build light in the first place-it's just simply the better way.

I want it to be a racer... the Rossi is powerful and gets high rpms meaning high speed if I select appropriate pitch... this is what I am going for... speed only... I might still end up in the safe range... the thing is what will the kit weigh if the flying weight is as stated above? the rest will go for tank, servos and engine...

Hi!
If you want speed go for a Q-500 racer and a 6,5cc JETT engine! Speed will be around 225-250km/h.