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Have replaced my rotors with new extruded which fly very nice although now the rear wheel tries to dig in on take off. I raised the wheel another 1"but it didn't help. I didn't have the problem with 27 0r 28 Larkins but now have 29 AK's. My machine used to hang at 13.5 deg with 170kg of passengers, and there is about 8" rock on the front wheel. Now have to take off like a plane. Was thinking of sloping the rotor head more but don't really understand if this will help as I have plenty of backstick. It feels like the tail just hangs for a moment while leaving the ground, but it's enough to slow your forward speed. I'm not trying to horse it off either. It's just strange that such a difference has occurred. Any help will be appreciated. Ken
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Ken,Couple of suggestions:1) Shift your mains back a little to increase the forward weight and control the lift off..2) Don't pull so much back stick, you've got a big difference in the lift on the blades, apparently.Have you checked your rear rotor blade clearance with it on the back wheel? If you adjust the back wheel up will it cause a rotor strike?Cheers,Nick.
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Nick, it is none of those things. I balance on the mains, but the thing is now like a fixed wing. Have already lifted back wheel. A little better but not much.I suspect it is more to do with the coning angle of the fabricated compared to the more rigid extruded. Also the thrust of lift has probably been moved back because of the bigger blades, but you would think this would have the opposite effect. Thanks Ken.
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Ken.......can you still get her up and balanced on the mains ?????If so....the rest takes care of it's self....ie Power on, lift offAlso, how much air between tail wheel and the ground, when you are sitting in the machine, on the ground??????I've noticed over the years, that too many machines have very limited ability to raise the nose rite up to get them blades honking, it is sure important to help you get off quicker, of course you don't overdo it, but the techneque to do it can be a real help, especially on the shorter strips etcjust my view.....Russ....A1014 NT....gods countryAlso I note your hang test is 13.5 degrees.....thats a lot,personally I prefer 9....11 degrees, actually closer to 9
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Diferent rotors will cause some takoff diferences. I'm not a techy Ken but you may have to get used to another method of getting off the ground. It sounds to me like you're trying to get off too quick,when the nose comes up with full backstick, ease the nose forward, still keeping the nosewheel just off the ground till she flies off on her own.Do you have a rotor rev counter??Brian.Would like to try a set of AK's 28 ft'ers.You never know how far you can go, till you get there !
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Ken,You'd be right about the coning angles, if your blades are a larger diameter, they would cone out at a lower angle.But the Rotor thrust vector is still the same, and on the same axis...Why the difference?Short answer is that I haven't yet thought about it for a solution..I'll get back to you when I have.Cheers,Nick.
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Got a rotor tac onit Ken?Them heavy blades take a bit more time to get to fly'n rpm, and if your not let'n um get to speed befor you pull back, they will just pull the head back without lift'n.I'll watch meself TO next time and note wots go'n on.I can still git it up, as short as I could with the lighter Goodwin blades, but theres a different way o do'n it.IOW, I gota think bout it.Ignorance is bliss............but only till you realise you were.Ingratitude stinks.......be generous carefully.
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I know what you mean Birdy, seems to take forever to get them bigger blades going for a start but once you get used to them, they can be pushed as hard as shorter rotors.You never know how far you can go, till you get there !
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My extruded blades are the same lenght as me old Goodwins, just alot heavier.[and more efficiant]They need more time to get their extra mass moving, coz after all, I'm still only use'n the same 26' area of air to spin um up.Ignorance is bliss............but only till you realise you were.Ingratitude stinks.......be generous carefully.
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Mate, thems big words.Bin chase'n cows gen this morn'n Ken, And I took note.Do the same as you did with the lighter ones, but when the nose wheel cums up,hold the tail wheel just off the ground. This'll give the rotors maximum air feed to spin up and alow you to gain AS quicker.Move'n the mains back a couple o inches will also help by allown you to force more air through the disc without dragn the tail.You may also find that the AKs will pick you up at lower rpms too.The trik is to not get caught behind the curve.There'd be nuthn gained by move'n the head.Ignorance is bliss............but only till you realise you were.Ingratitude stinks.......be generous carefully.
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I know nothing about it Guy's but what about if you also lowered the mounting brackets on the mains a little, giving a bit more clearance under the keel ?Would that make it easier to balance on the mains ?Cheers.Robert DunnMackay. Qld.Growing old is good while it lasts.
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Originally posted by BrianI know what you mean Birdy, seems to take forever to get them bigger blades going for a start but once you get used to them, they can be pushed as hard as shorter rotors.You never know how far you can go, till you get there !Geez......are you going to regret that one day....big flap going to happen, rite wind,powerful engine, it's onjust my view......Russ....A1014 NT....gods country
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I think you hit the nail on the head Bird. The tach reads 315 when flying but nose lifts at 160. Old blades were 180. I took my prerotator off so I might be rushing things. Once the old blades were doing 180/190 you could just gun it. I've got 7" clearance on the rear when on the mains & front. I'm only balancing the same as I use to, so will try balancing longer. The old ones would just fly off were these make you push the nose back down and run along fast. I'm use to jumping off the ground and flying along about a foot off until getting to climb out (50knts). Rough field take off. The other thing is my strip is slightly down hill and The extra lift may cause me to adopt a false sense of the horizon in relation to the strip. Thankyou everyone for your help. Will try a few things tomorrow and let you know. Ken
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[That poor nails gitn a floggn ]Another way o spinn'n your blades up quick is to raise the thrust line.[this shouldn't take long].Ignorance is bliss............but only till you realise you were.Ingratitude stinks.......be generous carefully.
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