Available teeter.........

[Greg Mitchell]

Given a rotor head is setup with +/- 9 degrees of teeter and then add some high density teeter stops which takes away a degree or two from each side, throw in some 23/35 knots variable gusting winds or aggressive forward stick and what do you get if your strap bolts are too long and in upside down and can contact the pre-rotator before reaching the stops..........

[birdy]

I mite be rong Mitch, but i think youd experiance patial blade stall [pbs]before you ran outa twwter. Pbs aint catastrophic, but you cant not know you did it, and it takes sum seriously hard input to achieve.

[Greg Mitchell]

I hear what your saying Birdy.I"m looking at the Butterfly teeter plate which has a slight bevel at the edges of the plate to account for a flat contact point between it and the hub bar. We then add a 3mm teeter stop at those points and we have now lost a given amount of available teeter. In other words we no longer have +/- 9 degrees, we have somewhat less.Given the outermost blade strap bolts if installed incorrectly can contact the bendix housing on my gyro and assuming one is out and about in blustery conditions as stated above and or doing hard pull ups, which the evidence above seems to suggest a teeter of +/- 8 degrees is not out of the question, then I am thinking perhaps I have marginalised my available teeter, thus putting me at greater risk?????I am enjoying throwing the gyro around a bit more these days and often flying in 25 kt plus blustery weather whilst doing so.Obviously I would like for the differing expert opinions to converge at some stage and reach a concensus as to how much a rotor system will/can flap in flight and the ramifications of same.Thanks.Mitch

[birdy]

Mitch, the old ruel mate."if it can, it will".If it can touch while static on the ground without effort, in the rong conditions, it will inflight too.A Rosco head with standard AKs dont give much teeter room, and the wasa with AKs and [ conveier belt] cushn stopers has even less, and i dout iv ever touched the stops inflight.Alota people who are violent on the stick recon the shake they feel is the bar on the stops. I dout it, its more like the inertia feed back from the blades from too agressive an input.Run a bubbleometer on the bar and findout wot your range is from stop to stop, and ill do same on mine. be interestn to hear.And if it hits the stops before anythn else, your rite as rain.

[Brian]

Given the outermost blade strap bolts if installed incorrectly can contact the bendix housing on my gyro and assuming one is out and about in blustery conditions as stated above and or doing hard pull ups, which the evidence above seems to suggest a teeter of +/- 8 degrees is not out of the question, then I am thinking perhaps I have marginalised my available teeter, thus putting me at greater risk?Huh?Great to hear you are getting some flying in Mitch and also enjoying the wind, shows you have you confidence up and the Butterfly is handling well!!I have always put the strap nut on the top which gives more clearance than the other way. I"m pretty rough at time and have had lots of shake but have never seen any evidence of contact on the bolt and I reckon it would have to be one very violent stick push to get it to happen but thats only my opinion.I"m like Birdy, if it can touch on the ground without effort, then it will in flight too!!

[Greg Mitchell]

Hey Brian,Only had the Monarch out twice since Easter but put nearly 5 hrs in whilst at it. I had a lot of thinking and some attempts at destructive testing to do. I was fine all during Easter at the Nats as you"d recall Mate but after all the forum stuff, guess I lost my "mojo" for a bit. You are right Chop, confidence is good and the flying is fantastic. Butterfly is rock solid. I remember asking Gra Gra and I think yourself how the Butterfly looked to behave in flight, if you recollect. She sure is a sweet flying machine. Thanks for the advice and comments. Love to Rosie and hope you both are having fun.G"Day Birdy,I have always admired your ability to succinctly express yourself and been kept grinnin over the years by your humour. Your second post says it in a nut shell for me.The extra fuel I carry these days gets me more fun, so thanks again for upgrade Bloke.Monarch is out at Cranbourne presently so it may be a week or two before I can do those measurements. That would be good to compare the numbers.

[birdy]

Just got back from anatha 6 hour mor"n, [ sorry Mitch, 50 odd hours this last 8 days, and counting. Just love to rub it in. ] but ill hava bite then finish off this arvi, and hopefuly remember the bubbleometer.If ya wana log sum more, get ya ass up ere n take the pressure off mate. [ bloke left a message while i was out this mor"n, just had a wing of camels trample their way in from the desert. Gess ill be do"n anatha sorti morrow. ]

[Brian]

Can understand full well being a little bit apprehensive, would be myself and its great you got through all that.The Butterfly flies beautifully and I certainly [from the ground] could detect nothing at all which suggested any bad manners and you were flying really well plus that prop note was probably the best on the weekend, it had a very distinct note. Love to Rosie and hope you both are having fun.Always having fun Mitch I have been doing my hours in the Cat road grader, only got it home in April and its been at least 20 odd years since the dam drains and roads have been done so its been pushing levers and listening to the Cat purring away behind me instead of the suby

[Adrian S]

Mitch,From my earlier blade testing (includes some time testing in 20kts + gusts) I have found that 5 deg each way to be the practical min for hub bar teeter before I started to feel minor "bumping" that scared the .....out of me

[birdy]

Seems your rite agin Adrian. ;DThe bubbleometer says 10* stop to stop on the wasa [ 28 and 30"AKs] and 10 1/2* on the ferel [ 26 and 27"AKs.].BTW, they both have soft stops.Last year a R22 owner was in the passenger seat and wanted to know wot its top speed was. I said i didnt know coz iv never left it nailed long enuff.Anyway, after i left it on full soot 3" off the deck it wound out to bout 120mph very promptly on the ASI, [bout 100mph true] and the stick was still smooth as silk. [ i stoped lookn at it after that.]Duno bout the ferel, never been brave enuff to look at the ASI wen im angry.

[Greg Mitchell]

G"Day Adrian,Thanks for the input....So the minor bumping is as it hits the limiting tabs?Is this a little past 5 degrees each way as it does this?My Pats spin at 360-365 rrpm 23 1/2 feet.Birdy, are you referring as to part or all,

[Adrian S]

Mitch,To clarify my post aboveThe test head has adjustable limiting tabs mounted on a spring steel leaf of each side of the head so that I was getting feedback through the stick before actually hitting the real stops IE the spring tabs are hitting the hub bar as the teeter goes past 5* each way but the real physical stop on my test head is at 9* each way - basically I didn"t want to die!. The conditions I was flying in that day was gusting 15 to 20kts and I was

[Greg Mitchell]

Thanks Adrian.......crystal clear to me now. I will be measuring the available amount of teeter since adding the bread board stops. Installed for two reasons.First, to protect the underside of the hub bar from marking. I was getting a line or groove developing, even though the edges of the teeter plate are bevelled to prevent/reduce this.The second reason, was to provide clearance of the inboard blade strap bolt which could make contact in a std Butterfly head (ONLY WHEN USING NON STD BLADES). Larry uses the un-named blades you spoke of Adrian on the Monarch and all the clearances are fine with the DW"s.Put a set of Pats on and a little less teeter provides clearance for the said bolt.Put that bolt in the wrong way however and the bolt can contact the bendix housing of the pre-rotator.Interestingly I have noted 20-35 rrpm drops in gusty conditions, with larger increases when heavily loading the blades.I need to do some carefull measuring/calculations.The easiest fix for me would be to get Rob to make up a 2 foot hub bar, presently using 1 1/2 ft bar. Would therefore give me clearance and 24 foot disc providing benefit for a heavier load. Thanks for the clarity.Cheers,Mitch

[Adrian S]

Mitch,One other option could be to reduce the thickness of the breadboard and increase the length of the Jesus bolt & spacer between the head bearing and torque tube. Convention says to keep this spacer as short as possible because increasing it can amplify any small errors in the head as well as leading to greater stick forces. I remember from having a close look at the MLS set up that this is already fairly long

[Greg Mitchell]

Good catching up Adrian. Hadn"t even thought about increasing the length of head/bearing spacer. As you note it is already longer than most.I recollect PB telling me once when I had the white Butterfly to cut the stalk down by an inch and half. Same reasons you state to keep it minimal as possible.I"ll do those measurements we talked about. Will discuss a new hub with Rob.Appreciate the help here.Fly Safe and Good Health.Mitch