If this is your first visit, be sure to check out the FAQ by clicking the link above. You may have to register before you can post: click the register link above to proceed. To start viewing messages, select the forum that you want to visit from the selection below. |
|
|
|
Thread Tools | Display Modes |
#11
|
|||
|
|||
aerobatic power to weight ratio
On Aug 5, 6:20 am, More_Flaps wrote:
On Aug 5, 11:47 am, Dudley Henriques wrote: Capt. Geoffrey Thorpe wrote: B. Control would be a problem. Hanging from the prop results in torque rolls. Airplanes don't have tail rotors or cyclic control over the propeller. A VERY effective demonstration of this can be done in a P51. You start from slow flight with the prop all the way up and slowly begin increasing angle of attack and feeding in more MP as needed to hold altitude. Sort of like any entry into a slow flight back side scenario. As you do this you will need more and more right aileron. You will reach a point where aileron can't hold it any longer and the airplane will torque roll on you. It's a VERY effective technique for demonstrating how NOT to get in high angle of attack/slow airspeed/high power situations :-)) -- I understand the reasoning/description here, but how/why do model planes do it so well? Cheers Many models often have out of scale control surfaces |
#12
|
|||
|
|||
aerobatic power to weight ratio
More_Flaps wrote:
On Aug 5, 11:47 am, Dudley Henriques wrote: Capt. Geoffrey Thorpe wrote: B. Control would be a problem. Hanging from the prop results in torque rolls. Airplanes don't have tail rotors or cyclic control over the propeller. A VERY effective demonstration of this can be done in a P51. You start from slow flight with the prop all the way up and slowly begin increasing angle of attack and feeding in more MP as needed to hold altitude. Sort of like any entry into a slow flight back side scenario. As you do this you will need more and more right aileron. You will reach a point where aileron can't hold it any longer and the airplane will torque roll on you. It's a VERY effective technique for demonstrating how NOT to get in high angle of attack/slow airspeed/high power situations :-)) -- I understand the reasoning/description here, but how/why do model planes do it so well? Cheers It's in the ability of the ailerons to handle roll inertia. The propeller on a Mustang for example is a Hamilton Standard 24D50. It's 11 feet 2 inches in diameter and weighs more than a Mother- In- Law! That monster can create more left turning tendencies than NASCAR. In the described scenario above, it's simply a battle between the prop and the ailerons. The prop wins in this case. -- Dudley Henriques |
#13
|
|||
|
|||
aerobatic power to weight ratio
Superdoof wrote:
Hi, I've noticed in the videos at www.fulldeflection.com that all the top aerobatic aicraft, such as the Sukhoi SU-31, Egde 540, Extra 300, etc., can almost hover. It seems that within a few years they will be able to climb on power alone. Aerobatics will look completely different once that occurs. Can you imagine Svetlana Kapanina hovering her Sukhoi for a couple of minutes at 300', then reversing down to an even lower altitude. I can imagine Peter Besenyei performing the perfect square shaped hover in his Extra 540. Is this technically feasible, or have the aircraft already reached a developmental limit ? Superdoof. If the trick is done with purely with power it really isn't that spectacular. Think about what you described above. It can be done today by a student pilot in a helicopter. |
#14
|
|||
|
|||
aerobatic power to weight ratio
|
#15
|
|||
|
|||
aerobatic power to weight ratio
"B A R R Y" wrote True scale r/c models often suffer from serious controllability issues in ugly attitudes. This is why r/c pilots are often encouraged to gain serious experience before moving to true scale warbirds, just like full-size! Another factor that has not been brought up, is how weight versus wing area, and HP to weight ratios of models versus full sized aircraft. Also, the effect of the air is different at scale sizes, which is related through Reynolds numbers. Thrust at model sizes is very easy to get way up over the total weight of the model. Not so easy with full scale. There is a rule among model builders, but I can't for the life of me remember what it is named, or exactly the numerical relationship. Something like "rule of square" or "rule of cube" or "rule of quad" or something like that. Basically, as I recall, it is that as size double, the wing area (or weight) is 4 times as much. I never got into that type of thing, since I am not into the whole accurate scale model stuff. As long as it is fun to fly, I'm happy. g -- Jim in NC |
|
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Fiberglass cloth weight vs 'finished' weight | Fred the Red Shirt | Home Built | 12 | April 5th 08 04:24 PM |
Glider Weight/Wing Loading and determing speed for best L/D for a given weight | 65E | Soaring | 3 | January 26th 06 09:26 PM |
Power setting table and best economy/best power... | xerj | Piloting | 29 | October 20th 05 02:44 AM |
Empty/Gross weight Vs. Max. Pilot weight | Flyhighdave | Soaring | 13 | January 14th 04 04:20 AM |
Diesel engines- forced induction, power-weight | Jay | Home Built | 4 | December 7th 03 09:23 AM |