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Post by sean on Aug 13, 2007 11:48:08 GMT 10
I agree, rudders are great. But I've flown a few slope planes with rudders and they tend to have very little effect when compared to a powered model. No knife edge for example . On these planes all they were really good for was smoothing turns, getting rid of adverse yaw etc.
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Post by ding on Aug 13, 2007 18:08:13 GMT 10
I agree, rudders are great. But I've flown a few slope planes with rudders and they tend to have very little effect when compared to a powered model. No knife edge for example . On these planes all they were really good for was smoothing turns, getting rid of adverse yaw etc. Not only do they have little effect for things like knife edge flight, but applying them tends to induce roll and pitch coupling to yaw as the aeroplanes aren't designed with aerobatics in mind generally. We used to go to great length to eliminate this in F3A models by adjusting things like wing to tailplane height, C of G, wing/stab incidence, size and shape of frontal and vertical stabiliser areas etc. Even if these issues were addressed in a glider putting on a lot of rudder induces massive drag so it's debatable whether they would ever be able to ever carry rudder in a sustained manner except as a drag inducing manoeuvre without a big fan upfront. The coupling effects can usually be mixed out electronically but there are usually peculiarities that come with this. Having said all that, as you've said they enable you to clean up turns (HUGE positive), perform super cool looking wing overs and stall turns, and do spins and snap rolls (crowd pleasers). Another little utilised function of rudder is the ability to do sideslips to wash off speed. This is a training manoeuvre in full size gliding, but throughout my modelling I've hardly ever seen it used as it can be difficult to sustain and transition out of. It was very effective on my slippery F3A models. I'm sorry if anyone passes out with boredom from the above, but that's why Steve **really** misses flying planes rudder. After 10 years of teaching myself to use it I sometimes wonder if my left thumb is fading. TRIVIA 101. Rudder is the only control surface that can go through a triple reversion when operated from a fixed position outside the plane. Anyone care to have a stab (groan) at explaining that ?? ;D ;D
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Post by ding on Aug 13, 2007 18:48:41 GMT 10
Two Aldi assorted cremes from my biscuit barrel to the first correct answer ;D
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Post by jase on Aug 13, 2007 19:08:24 GMT 10
you'll prob eat the biscuits before they get to the winner.
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Post by sean on Aug 13, 2007 19:26:52 GMT 10
I think it means the rudder can cause a break in the time/space continuum.
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Post by callun on Aug 13, 2007 19:33:08 GMT 10
TRIVIA 101. Rudder is the only control surface that can go through a triple reversion when operated from a fixed position outside the plane. Anyone care to have a stab (groan) at explaining that ?? ;D ;D Something to do with whether the plane's inverted, coming towards you or going away from you?
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Post by ding on Aug 13, 2007 19:36:26 GMT 10
TRIVIA 101. Rudder is the only control surface that can go through a triple reversion when operated from a fixed position outside the plane. Anyone care to have a stab (groan) at explaining that ?? ;D ;D Something to do with whether the plane's inverted, coming towards you or going away from you? If you can explain it a little more the biscuits are yours. Ie. left aileron stick gives left bank on a plane going away from you. However left aileron stick turns the plane to the right when the plane is heading towards you. This is the same when the plane is upright or inverted.
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Post by ding on Aug 14, 2007 18:10:55 GMT 10
Sorry, I passed out last night... LOL Anyway Callun was definitely on the right track. Here's the story. Elevator Operates the same from in front or behind. Control reverses when inverted from the front or behind. Aileron Control is the same from behind the plane. Control is reversed when viewed from in front of the plane. Control is the same inverted Rudder. Control is the same from behind the plane. Control is reversed from in front of the plane. Control is reversed from behind the plane when inverted. Control is reversed twice when viewed from in front of a inverted plane. So, it's a unique control surface Here endeth the hi-jack.
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Post by jase on Aug 14, 2007 18:47:33 GMT 10
ok. hope someone can help me out here.
we took the macchi out for a fly at mt Mee this afternoon. wind conditions were SE up to 15kts. the Bees has no problem what so ever getting extreme height.
but the macchi did. this is where i need some help.
when we apply full elevator the plane (tip stalls - so-to-speak) harshly to the left. also the plane was having trouble gaining altitude.
now the altitude bit i think we figured out by adding a heap more weight just infront of the COG. now a heap of weight is approx 100 - 150g's. the plane few quicker and was marginally easier to handle. but still had lift issues, yes it was better than no weight at COG, but compared to the Bee. it was a slug.
for this i'm going to get a lead sheet from bunnings and just Trial and error until i get it right... the other thing maybe that i didn't have enough wind to fly this plane properly.
my main concern about the whole thing is the wing tipping with up elevator to the left. very harshly.... any comments on this would be greatly appreciated.
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Post by jase on Aug 14, 2007 18:49:03 GMT 10
oh yeah.. callun ran my plane into the barb wire fence
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Post by ding on Aug 14, 2007 19:06:27 GMT 10
oh yeah.. callun ran my plane into the barb wire fence Just be thankful he didn't get it run over C of G is normally a primary cause of this but you say it's more nose-heavy than the manufacturers recommendation which would tend to rule that cause out. I'd look at the following. The first thing i would check would be to look along the back of the wing, and see if it bends up or down towards the tip. Bending down in particular could cause tip stalling. This is called "wash-in". Some planes have built in "wash-out" where the wing tip is bent up slightly. This reduces the angle of attack at the tip and is done to reduce tip stalling. So don't just look at the left wing, look at the right to see if it has washout as well. Warps are easy to put in a plane accidentally while covering. Second thing I'd look at would be the movement of your elevons. Make sure when you pull on elevator you're getting the same amount of throw on both sides. Third thing is the wing weight. Check that it is not significantly heavier on one side than the other by putting your fingers under the middle of the plane and see if it rocks one way or the other. I don't consider this a likely cause. Let us know what you find.
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Post by ding on Aug 14, 2007 19:08:23 GMT 10
Jase... you can ring me if you want.
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Post by ezza on Aug 14, 2007 22:11:26 GMT 10
Hey Jase,
Sometimes too much elevator can cause a plane to tip stall. Set up with dual rates that way you can flick back and forth and see if less elevator travel helps.
I have found that pretty much all kits I have built, fly better with the C of G atleast a millimeter or two behind what is recommended.
If we get good winds this weekend (fingers tripple crossed) I might see you at the slope and could have a look at it, If you don't already have it sorted.
Regardless, I think this sort of plane will need good strong lift, probably 15+knots. There are some guys down here with the old warbird style (P-51) planes and they don't fly them until it is 20+knots.
Good luck!
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Post by callun on Aug 14, 2007 22:34:40 GMT 10
It flew a bit like a dog at first, but just flyable. It wouldn't climb, would barely hold its height, and wouldn't come even close to a loop or anything like that. It flew better upside down.
With the extra bit of weight, it immediately climbed more acceptably, and held more energy. Still wouldn't loop, and rolls were a bit clumsy. It was incredibly slow - both the bee and my warrior would easily out-perform it in almost all aspects. An interesting bird - I look forward to seeing/hearing about its progress.
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Post by GotrekGurnisson on Aug 14, 2007 22:36:43 GMT 10
It will fly like a pig regardless of balance in the sort of winds we get around here. It's too heavy and the wing loading is too high. Those sort of planes are designed to be flown in 20-30 knot winds.
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