One little job becomes a Baker's Dozen.

[birdy]

Ya rite agin Kaptn. I was thinkn of "free play" like ina drum setup, but as you say, theres only half a poofteenth play ina disc.

[birdy]

A slightly taller gearing on the prespinner drive woulda been an easier fix i woulda thort.

[Greg Mitchell]

Explain that fix to me Birdy and I"ll let you know if that is easier than putting my hand in my pocket and spending less than $100 AUD now on the 1/2" MC brake assy"s which Larry is using on all 582 and 912s driven pre-rotators ......you keep forgeting how mechanically inept I am. Mitch

[birdy]

If Larry hada slightly bigger drive pully, or smaller driven pully, you be getn your desired rrpm at lower erpm, so you dont need buggerall in the way of breaks.In fact, if you gear it rite, the rotor acts as a break, [ full backstick] with enuff power to hold the machine back, without ground breaks.The ground breaks on the ferel are only there as a dead weight [ not real effective IOW] , but coz im getn bout 280 odd rrpm at bout 3400 erpm, [ bout 40% power], the rotor is do"n the majority of the "holdn back".Wen im getn near max prespin rpms, there isa big down wash and a cloud of dust in frunt of me.

[birdy]

Also, once you get to a certain rrpm, the best bearks in the world arnt worth two knobs, coz theres no weight on the tyres.The higher the rotor rpm, the greater their "breakn" power.

[Brian]

If Larry hada slightly bigger drive pully, or smaller driven pully, you be getn your desired rrpm at lower erpm, so you dont need buggerall in the way of breaks.In fact, if you gear it rite, the rotor acts as a break, [ full backstick] with enuff power to hold the machine back, without ground breaks.The ground breaks on the ferel are only there as a dead weight [ not real effective IOW] , but coz im getn bout 280 odd rrpm at bout 3400 erpm, [ bout 40% power], the rotor is do"n the majority of the "holdn back".Wen im getn near max prespin rpms, there isa big down wash and a cloud of dust in frunt of me. Well thought out there Birdy !!

[Greg Mitchell]

Hey Birdy,A bigger drive pulley (I"m assuming that"s at the engine) is not possible with my pull start set up. The "drive pulley" is situated between the engine and the pull start and is thus restricted in size to be able to be fixed (retaining bolts for pull start cover) where it is. I see smaller fly wheels ( again I am assuming this is the "driven pulley" ) at the rotor head on other gyros.With the extra holding power of the 1/2 bore MC Hegar 1000lb brakes, Larry can hold the gyro to 6250 engine rpm, which gives 325 rotor rpm and 3 -5 second lift off. This is std on the Monarch and Aurora. 325 is full flight speed on the DW"s. As the take off roll is initiated some rotor rpm is lost and then quiuckly regained. The difference between 325 and 270 may not seem like much but is measured in take off roll and time to clear the ground. The MTO3 got off quick but he was flyin straight into 25 knots of wind and his whole flying display was based on the amount of usefull "wind" assistance.The other night I watched a Youtube MTO3 spin up.

[bones]

If this prespinner i got nearly finished works it should be ablee to give about the same rpm i hope, not that i need it too be that high, i think 270, and then go should be fine, after all we are only lower classs scum gyros not helos you know

[birdy]

270 is plenty Bones, you only need to get um to low flight rpm, then you gota get min AS and way y go.

[Greg Mitchell]

I agree 270 is plenty.I"d be happy with 250 which is what I thought the Xenons were getting Bones.???What is redline engine rpm on the 912s?Mitch.

[bones]

I agree 270 is plenty.I"d be happy with 250 which is what I thought the Xenons were getting Bones.???What is redline engine rpm on the 912s?Mitch.Mitch there is no reason with the gearing they have got that the rrpm couldnt reach 300 mark, but i have only taken it to about 270-280 rrpm not sure exactely as things were happening real fast so i wasnt watching the tach closely but the last time i looked it was going passed 250, was 2 up on a short dirt road, and it was off real quick.Most of the time i just go to 200 and then full noise, and the nose pops in about 50mts then we are off.The 912 has a red line of 5800 only for 5 mins then drops back to 5500 for as long as you want.

[Greg Mitchell]

Thanks Bones.I"ve been getting to 195-220 and then go full noise.New 1/2" MC cylinder arrives Monday/Tuesday.

[gbw]

"On the go karts we"ve got I have experimented with this and got better results when cold with a smaller surface area, but a much quicker wear rate."Ken,What you say agrees with a formula I seem to remember from the distant past. On a car it is weight (pressure) per square inch. The smaller the area the greater is the effect and so the greater the stopping power. Theoretically skinny tyres should work better. But then you bring in coefficients of friction etc.That sleeve suggestion is great. I have an MGTC on blocks. When I was driving it I had problems stopping the bugger, so I looked for a smaller bore cylinder. I could not find one smaller...Looks like it might come off blocks soon, so I will keep thi in mind when I do the brakesGraham

[Brian]

I read with interest the need for brakes while pre rotating, I know that with the Magni, prop clearance is a factor and with the MT 03 the handbook says to do it with the disc flat but with my old Rosco, no brakes are needed

[Ken Watson]

Be careful Graham as the TC has drum brakes and volume is more critical. If the master volume is not enough you will not push the shoes far enough and as such run out of peddle. Some shoes come off a long way: much further than a disc pad. My mum has still got her TC manual in its original envelope and the wire wheel hammer is kicking around the shed somewhere. I was going to buy one a few years ago but couldn"t fit in. Have now decided I want a PRB or similar. When I figure out how to post a photo I"ll have to post a photo of my driveway. Motorhead Heaven. Ken