Disc Loading....what is too low?

[Brian]

No need apologizing Tony, I knew what you were talking about. Just thought I would throw my answer in for those who might have less experience.And BTW, I"m one who has a few hours up on my gyro but have little knowledge of flying other makes so I"m very familiar with the Rosco but I know that other gyros are going to be a whole new ball game.The recommended disc loadings are probably the area to start with.

[MilesW]

Tony,Disc Loading is derived by dividing the AUW of the Gyro by the Disc Area...this will give the upper limit.Then do it again empty of fuel. There"s your ultimate lower limit.Pie (3.1416) X Radius Squared (Feet) = Disc Area (sq/ft)AUW (lbs) / Disc Area = Disc Loading (lbs/sq/ft)21 fT Blades21 divided by 2 = 10.5 radius ftTherefore, radius squared is 10.5 X 10.5 = 110.25 sq ft3.1416 X 110.25 = 346.36 sq ft500 lb AUW Gyro Divided By 346.36 = 1.44 lbs sq ftCheers,MitchThis is a bit like looking at a "penny dreadful"s" books. Something just aint quite right. At the very least, wouldn"t the disc area be the total swept area less the non effective area of the hub bar?

[Greg Mitchell]

Miles,There must be more math! A fairly complex formula with quite a few more variables I"m guessing.Like I have stated above several times, eliminating the need to "guessing" there is an excel program which is far more detailed and includes many more variables.This is what the gyro community have been using for a long time now, if it is so dreadfull, then OK, so show us the real math.The above formula for calculating disc loading is the basic std formula.Birdy,We can start with 60 footers then and work back from there!Mitch.

[Greg Mitchell]

"usually connotes rather careless and second-rate writing and gory themes."I"ve had a few private emails today asking what a Penny Dreadfull is.......Careless and second rate.

[MilesW]

"usually connotes rather careless and second-rate writing and gory themes."I"ve had a few private emails today asking what a Penny Dreadfull is.......Careless and second rate.

[Mark Horan]

Actually, when people come into a topic fresh, they can quite often make observations that those of us with "Knowledge"

[birdy]

Very rong Hoorang, how can you measure a "disc" in "square" feet.

[Greg Mitchell]

[b]Actually, when people come into a topic fresh, they can quite often make observations that those of us with "Knowledge"

[Mark Horan]

Actually mitch,What it will give you is the same loading on the teeter bolt.....if you can get enough power to get the machine off the ground.Good luck with your modifications ;DHORAN

[Greg Mitchell]

Obviously Horan it is riduclus to think with all the other parameters that the thing would fly....however, it is still an imaginary disc, whether spinning blades or lumps of wood, with a calculable loading......not a teeterbolt loading formula. We can agree to disagree I guess.I must concentrate on other matters now as I believe this thread has run its course for me.Thankyou for your offer of good luck with my mods. ;DMitch

[Greg Mitchell]

Seeing as I kicked this thread off I should advise on where it has led me to and the decisions made for blade and loading selections.Just confirmed a set of 25" Gerry Goodwin Blades. Fabricated bonded alloy with 1 1/4 lb tip weights. 7 3/8" Chord.Total weight 25 footers approx 59 lbs give or take the inaccuracy of the bathroom scales.I believe a set of Dragon wings is around 53-55 lbs. The Goodwin Blades can be hand spun.The tip weighted blades were recently tested by a well known experienced pilot who ordered a set immeadiately.At my AUW at sea level the new GG blades will spin up around 363 rrpm with a disc loading of 1.42 psfMT the blades will be spinning around rrpm 348 and disc loading of 1.30 psfAt half fuel 356 rrpm and disc loading of 1.36 psfWith a full load of fuel at 2,500 feet rotor rpm will be up near 380 rrpm, which is where I am at now at sea level on take off fully loaded with a dic loading up around 1.52 psfFurther by adding the Goodwin blades I save 17 lbs off the weight of the Patroneys and increase my disc size from 23 1/2 " to 25 "

[GraemeMonro]

Now you blokes have done it, I think you broke my brain.

[tonydenton]

mitch, thats great news. i"m not saying stay with them for ever but they are great fun. you"ll notice the difference with the lighter rotors, easier spin up. i will be drooling over your landing gear. please us up to date.

[Greg Mitchell]

"As stated before, I have flown over 1,400 sets of blades, all the way down to .9 lbs. per ft.I can say WITHOUT reservation, that anything below 1.3 is BAD! It will cause the little B"s to be like a leaf in the wind! IF, and I say If, you were to ONLY fly in dead calm wind then it MAY be safe to use 1.0 lb.per ft.. But, back in the real world, we know low time pilots, especially, will not know when to NOT fly, until it is too late! the ONLY way I can help prevent this from becoming a BAD thing , is to offer my experience and NOT sell blades to a person , knowing it is WRONG!"Ex USA Forum......Gives a definitive statement with a "number".Sure he"s only one bloke, with one point of view.....BUT he"s been building gyros for many, many, years (Dominators) and has flown various craft and blades through out those years, with different blade loadings.Based on Ernie Boyettes experience and knowledge, I"d be inclined to at least listen to this advice.MitchPS. Tony I"ll give you a ring when I have the Goodwin Blades up and flying.

[birdy]

Your safe Mitch, Jerry rang yesterday.