Flying when heavily loaded

[nullack]

nullack, try the same flight without flap seals and wheel fairings, and with the 172R prop. See what kind of performance you get then.

Hook

Gday Hook. So I tried it, back to the slower prop, no fairings on any wheels and no flap seals. Same airport, same overweight loading and so on. It was more dicey but I was still able to takeoff and eventually maintain a climb between 200 and 110 FPM. I was able to turn around and land fine from the takeoff airport.

[Great Ozzie]

Hi nullack,

As L.A. mentioned, there is the ability to get a "Ferry Permit" that allows for an increase in Gross Weight for that specific flight.

Not only do you have the reduced climb performance, but there will be a necessary decrease in Vne and Vno and the permissible G loading on the aircraft. When you fly over GW, you reduce the structural safety margins built in during the certification process, safety margins that keep you from bending or breaking components necessary for a safe flight.

Another consideration is the increase in stall speed. As weight increases, so will the stall speed.

A real good read on this "Load Factor" topic is a U.S. Navy flight manual Fundamentals of Aerodynamics (online read). Or you can google this title and download the .pdf. There is a section called Turning Flight that begins a discussion on Load Factor -- leading into a discussion of the V-G Diagram for the T-34C (Mentor). Very good info on what happens with excessive structural loads / airspeeds. Just keep in mind every airplane will have its own V/g diagram.

As L.A. said, one must use the POH to establish performance figures / limits. The sim does provide an excellent springboard into some serious discussion. But as far as trying to replicate performance 'outside the envelope', I believe this is far beyond the intent of this sim.

Rob

[CAPFlyer]

And there was an electric transfer pump (powered by a thin wire connected to the CB panel) that fed the high-wing aircraft's fuel system from the bladder tank down on the floor.

Quick note on this item - The DHC-6's fuel tanks are located in the belly of the aircraft. The transfer pump on the bladder transfers fuel into the tanks below it where the main system boost pumps feed fuel to the engines. There are multiple cells that make up the tanks (I think 8 total, don't remember what I read on PPRUNE), but they are divided into Forward and Aft tanks. It allows for better servicing of the aircraft since until the Viking Air version, it was gravity fueled instead of single-point. On the other hand, the Cessna 208 uses overwing fueling with the tanks in the wings, but there is an STC for a single-point pressure fueling system to be installed on the aft part of the left main landing gear fairing which is used on all Amphibious models and retrofitted onto most of the Cargomasters and Grand Caravans.

[cessnaman]

If one ever takes real lessons, hopefully the instructor will take you up with a friend, maybe some baggage, so that you can see yourself (in a more controlled environment) what it is like to have an airplane closer to its Gross Weight and a further aft c.g. than what you may normally be used to (just you / the instructor).

Funny you should mention that. I remember when my flight instructor wanted to take a 3rd person and I said, sure. Well, on our takeoff I was wondering why our takeoff roll was longer than usual, then I realizied that the weight of the 3rd person and that person didn't look like he weighed much. Maybe 180-190.
Man, I sure miss flying. Wish I was able to finish flight training, but fiances forced me to stop. Maybe someday I can, and I hope me flight instructor is still around. He's a old timmer with lots of military and civil flights.

[Rarebear]

I have flown a Cessna 172 full gross and I never experienced it so sensitive. Not the same aircraft but I have also flown in a 182 where full forward trim was needed to fly. (thats how heavily loaded it was). Still flew sluggish but stable.

I do not agree with the way the 172 acts during flight when loaded. Where I did notice a difference in the way the 172 flew, was during flare. I was descending a little to fast and corrected quickly and it cause the cessna to porpoise. I had to add power to maintain airspeed and fly it back down to the runway. Other than that I have always noticed the 172 and 182 fly very well overloaded.

JDW

[Rarebear]

I am no engineer, but I seem to remember from my flight training that it is not straight line speed that has potential to damage the aircraft, but G forces. So, as Great Ozzie stated above, flying in the yellow arc in smooth air (and exercising caution in maneuvering) is permissible. It would be interesting to dive the A2A C-172 into VNE and see how it reacts to pulling out of the dive. In the real aircraft, this would probably cause catastrophic failure.

Jim

I have been in a 172 that went about 15 to 20 kias over VNE. Thankfully I am alive. I did not start the maneuver that put us in VNE speed but FAA would have stated i was pilot in command. Not one of my brightest or proudest moments.

I was also a passenger with an old geezer pilot in a 1956 182 that pegged out in a dive. Still alive. Would I do it on purpose? Never. I dont even fly close to yellow arc if im loaded. Too dangerous even though you would probably pass out before you bent the aircraft.

My father is a IA with over 30 years of experience and he has told me that he has seen aircraft with damage on components such as engine mounts etc. from turbulence even Wing bolts. But hes never seen a bent wing empenage or rudder. Cessnas are tough birds but it'd be best not to push ones luck.

JDW