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Thinking about Mosquito.
#11
The torquing on the helicopter wouldn't change because the movement is caused mostly by the friction and inertia of the mainrotors vs. the body. The tailrotor is used to counter the small % of resistance to turning that is caused by the main rotors pushing against the wind and their own inertia (and various other small factors). The amount of resistance is constant in our situation since the rotors arn't spinning any differently regardless of horsepower. In the case of rotaries horsepower is simply the ability of the main and tailrotors to resist decelerating (or bogging) under high-drag situations (when the rotors are pitched). Naturally, a helicopter will want to rotate more when you increase drag on the mainrotors because the extra drag is translated to a directly porportional amount of force on the body going the opposite direction. The power of the engine just enables a helicopter to sustain a higher amount of drag on the mainrotors, which in turn would make it want to rotate more... but only in those situations where the original engine would bogg or die completely.
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#12

Droolguy - 4/17/2010 11:04 PM The torquing on the helicopter wouldn't change because the movement is caused mostly by the friction and inertia of the mainrotors vs. the body. The tailrotor is used to counter the small % of resistance to turning that is caused by the main rotors pushing against the wind and their own inertia (and various other small factors). The amount of resistance is constant in our situation since the rotors arn't spinning any differently regardless of horsepower. In the case of rotaries horsepower is simply the ability of the main and tailrotors to resist decelerating (or bogging) under high-drag situations (when the rotors are pitched). Naturally, a helicopter will want to rotate more when you increase drag on the mainrotors because the extra drag is translated to a directly porportional amount of force on the body going the opposite direction. The power of the engine just enables a helicopter to sustain a higher amount of drag on the mainrotors, which in turn would make it want to rotate more... but only in those situations where the original engine would bogg or die completely.

No, the torquing is caused by the drag of the rotor system and the energy required to keep the blades spinning against a fixed (by means of a tailrotor resisting torque) helicopter. Very little is caused by friction.

MORE weight requires proprtionally MORE horsepower which requires proportionally MORE torque.

If you desire to operate at higher gross weights, you will require more power. Not necessarily more power than the engine can produce, but possibly more power than the aircraft is designed to sustain.

Helicopter operations require transient loads that are often much higher than the sustained loads that we put them through. In some cases, these transient loads may not increase proportionally with weight. They may go up with the square of the weight.

This is really a question for the designer. How much more can the MGW be increased w/o requiring stronger parts?

More efficient blades = GOOD (if that is possible)

Larger blades for more lifting = structural considerations

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#13
Isnt it funny how everyone that doesnt own a Mosquito wants to change it, I love my Mosquito just how it is, It has tons of power and Im no lightweight. 104 KG
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#14
well said Blair!
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#15
I second that Blair. I can appreciate people that want to get into a debate over one aspect of the mosquito or another and them getting engaged in conversation about a machine that they may have never flown or may not have even seen in person and observed just how good of a machine it is and how well it performs. I think it's all in good spirit though with only the best of intentions in mind. I actually think it's a compliment to the mosquito that people have that much confidence in it that they think they can do even more to it and make it even better. I kind of look at it like souping up a car. Some people will get a Camaro or a Mustang, already fast cars, and want to add high performance parts to make them even faster. You never see anyone wanting to add performance parts to their Hyundai or Volkswagen and trying to turn them into muscle cars! So, to all of those rotor-heads who want to make changes to the mosquito, keep bringing on the suggestions and the debate but just keep in mind that this is already the best little single seat helicopter on the planet and we really just want to keep it safe, simple, and affordable. Smile
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#16
In ray prouty's VOL 2 book of aerodynamics, he has an exercise that tries to make the blackhawk lift as much as the ch53 but do it using the blackhawk engines (power). He explains that it is possible to do but it isnt makeing the chords thicker. He says the rotor disc needs to be larger in diameter to keep the disc loading low enough for the horsepower. But he continues to say this isnt worth doing because when you extend the rotorblades, you must extend the tailboom. If you extend the tailboom, you must extend the cockpit to keep center of gravity in check. Now you have just added more weight which isnt the killer in his exercise, its the amount of parasitic drag. You may be able to lift more but you will have such a slow forward airspeed. People think about lift being velocity squard, but drag is velocity cubed. And agian, i think about such a long tailboom needing to flex. a tailboom any longer would flex more. you would need allot more flex packs on driveshafts just to keep the drive shaft from breaking when it flexes with the tailboom. So according to Ray W. Prouty (whom i think is a aerodynamics prophet) it can be done, but is the trade off worth what you arre trying to do. You could lift allot but you couldnt get any distance whithout needing fuel.
Something positive though, there was a racecar driver who knew nothing about aerodynamics, put a slat, or flat bar on the back of his car to hold it down on the track. Aerodynamicist could tell you a hundred reasons why this couldnt work. It would do nothing good, only make drag. After winning a few races, the aerodynamicicts started doing some tests. They found that it lowers drag while increasing lift (downwards because it was a spoiler). So not everything is written about what is best on helicopters. That is why there is many types of helicopters. there is no consenses yet. So please keep trying.
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#17
Everytime this stuff comes up, I learn something! Thanks everyone for making the effort and spending the time! Marks point is right on, and our little humble Mosquito is great enough to withstand and hold up to many proposed improvements, - yet it continues to be improved, like Ben Franklin said: "Without continual growth and progress, such words as improvement, achievement, and success have no meaning." ... and ... "Being ignorant is not so much a shame, as being unwilling to learn." I'm ignorant! Blair is soooo right, .. I remember when I wanted to change it, ha, not now after 21 hours flying it and getting to know and appreciate the engineering that went into it, everything in it's design has a reason behind it, an elegant simplicity - that WORKS!
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#18
I would like to state for the record that I will buy the XET regardless as they *are* amazing little helicopters. The whole reason I choose them as my starting point was because they are already the best at what they do.

These are just hypotheticals right now because I have never left any vehicle or aircraft I have ever owned stock, my passion is in building and tweaking things within an inch of their lives (and mine, sometimes). I like making things better, and starting with the best platform gives you an advantage in the end because the less supporting modifications have to be made to the original.

So right now, we have 2 things that are agreed will increase the performance of the helicopter without causing any ill effects.
1. Sweeping the mainrotor tips to get rid of tip losses.
2. Making the mainrotors lighter (without sacrificing strength).

P.S. You said the same thing I did on why a helicopter rotates, i'll agree that I was wrong to use friction as a major factor though... at the time I was assuming someone would use it as being synonymous with drag. That was my mistake because they arn't really the same thing.
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#19
I would agree with those two statements. But i would like to add that like John U said, the disc loading is so little that tip vortices as they are now, have very little vorticies.
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#20
droolguy, just wondering if you ever got a xet in the air. any performance mod done? keep on dreaming. 
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