GordonFreeman

What are the concerns of "overpowering" an airplane? This is from a 3D perspective. And let's be reasonalble, say 2:1 to 4:1 power to weight, not 1000:1, at which I think servo resolution might start to be an issue.

Let me lay down a couple first, even though I only consider them to be percieved problems:

1. The plane will fly too fast and break apart. That's what the throttle is for.
2. The lighter airframe can't take the virbration. Semi-valid, but not really resulting from being "overpowered".
3. The motor is too heavy. Again, semi-valid, but if the plane is balanced and the power to weight is sweet, I don't see the problem. Also, again, not really an "overpowered" problem.


The only thing I can think of is if there is more thrust (force) than the mount/structure can take and the plane comes apart from the acceleration. I would call unuseable power.

Thoughts?

Kurt P

Unusable power is overpowered to me!

1) plane is not strong enough for motor: overpowered to me. If you never can use full trottle, it's overpowered

2) and why is this not the result from overpower??? Is it a result from not enough glue than??
If a plane can not handle the motor, it is overpowered !

3) A plane can be balanced, power to weight can be more than 2 to 1 and having a terrible plane.
ex. take a 3D plane of 150cm , and f.i. a Zenoah 45cc and 500 gr lead in the tail for correct balance
--> result: balance OK, Power/weight OK but wingloading ???? So I see a big problem

3D flying is more than prophanging, you need to fly an to land it to. Otherwise get a heli !
Wingloading is also very important. not everything can be solved with extra power.

BMatthews

I don't think we have a definition of over powered any more...

Consider that a typical fun fly model fits your definition as layed out above. A typical contest fun fly can NOT use full throttle in level or even slight climbs for any more than a short burst or terminal flutter or airframe failure from excessive airspeed will result. These models only use full power at very specific times in their flight but at those times it's critical to the success of the flight mission. Based on that I don't think you can call them overpowered.

Basically it's not the engine that makes any model overpowered but it's often the engine that is capable of driving the airframe beyond it's maximum tolerable airspeed. I believe that for full sized aircraft this is reffered to as Vne for "never exceed velocity"

The only engine related issue that pertains here is the vibration one. And as you point out that's a design flaw.

Now overpowered PILOTS are a different issue...

50+AirYears

I did have an overpowered plane once. A Ted Strader P-51 from March 1958 Flying Models. With a Max 30 R/C at idle, 9-4 prop, it could not be slowed down enough to land. Of course, I was using a 3 channel modern proportional radio that weighed about 13 ounces installed, and the plane was designed to fly with a K&B 09 and a babcock magic carpet radio system that probably weighed over 28 ounces with batteries.
The plane had to be landed dead stick.

BMatthews

Ah, I had not thought of that aspect. OK, in that case I once helped a new modeler that had a Golberg J3 with an OS 60 in it. The engine was too new or not adjusted right to get a REALLY low idle. At the end of the otherwise VERY successful first flight I idled back but it would NOT land. Just floated by and CLIMBED at idle. I tried to get the model into a nice mushy high drag decent but no go either. It just climbed in a shallow uphill glide. Next pass I cut the idle back further using the trim. Still no go. Finally I got in the right spot and just cut the engine and deadsticked it in. I swear that model would have flown nicely with a 25 in it.

So OK, I agree that the definition of an overpowered model is one that you can't land even at idle....

Balsa Master

deffinition of overpowered:

when serious modifications must be made to allow the engine to FIT in the plane i.e. my .60 corsair being built with a 1.08...

Gizmo3D

BMatthews raised a good point. Having flown contest fun-flys at the British nationals I know ALL about flutter! Full throttle in level flight can be garunteed to remove your tailplane etc!! However when doing such silly things as looping touch and goes/looping limbos etc. you need a LOT of power to accelerate quickly. A hard touch and go for example can all but stop the plane, yet the plane must climb vertically as soon as its airborne. Full throttle is used for prehaps a second or less depending on flying style/ability etc and the flight speed is never allowed to build up. So overpowered in a conventional sense?... yes. Overpowered for competition? Nope! So the definition of overpowered is very much dependant on the role of the aircraft. Bearing in mind the UK record is 56 touches in 2min (a rate of almost 1 touch every 2 seconds!!!) a LOT of power is needed for the necessary performance.

Another major problem with too big an engine is torque. Generally, big engines use big props, and if you have a dirty great prop on a smallish plane then you could run into a few handling issues (both on the ground and in the air). Much rudder maybe required to track straight on takeoff for example. There will be a point where the advantage of having extra power is outweighed by the detrimental effects the power/torque has on the handling. If you read about late WW2 fighters you'll know that they were right on the limit of power versus handling characteristics.

However, coming from a 3D/freestyle/fun-fly type background i'm more or less of the opinion that you can't have too much power!!!! I always find myself wanting a touch more for those vertical figure of eights etc. `

GordonFreeman

Ah, too much torque that the airframe twists from too big a prop. I'll take that one. But not the idle problem, not a true "overpowered" problem, that is a "engine-too-big-won't-idle-low-enough" problem.

Thanks for the thought and input so far!

ps. no comments on my excellent (if I do say so myself) job of inverted hovering a Funtana 90 with a reverse pitch prop? (avitar)

Ebola0001

my comment would be nice picture edit

i believe the original picture can be found in the review
http://www.rcuniverse.com/magazine/a...article_id=373

and you just inverted the plane in photoshop or equiv.

:P

GordonFreeman

Well..duh.. But it was kind of funny though.

Ebola0001

yeah would be interesting to build one that could do that, but i think that you would have to have helicopter type control of the propellor blades (collective and cyclic) to be able to hover like that. there would be no prop wash to work on the control surfaces

when i first saw it i was thinking "oh the lase moment of a plane before the *thud*"