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  #46  
Old 01-27-2007, 07:34 PM
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Dennis Passey Dennis Passey is offline
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Oh yes by all means- and have the PP's claws sharpened! We might as well make this an annual event!
First to rotate and .....motate!
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  #47  
Old 01-27-2007, 10:39 PM
eracer113 eracer113 is offline
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Just for information, the mains on the E Racer are at either 113.0 or 113.5, I would have to check my W&B sheet which I will do. The stock E Racer with that axle location has 75 lbs on the nose gear, without anyone in the aircraft. Full to empty fuel only changes the CG by .2 aft. I would not recommend to anyone to change the axle location on the Cozy 4 from designed location.

Jack
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  #48  
Old 01-30-2007, 05:09 PM
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Quote:
I'd hate to see anyone taxi back from the first (long runway) high speed taxi-test and have to take out the sawsall.
The best logical quote from this whole argument. Go ahead, it's only another couple hundred hours to fix. On the other hand, lets get finding those fellas who did it on the Longs and ask them.
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  #49  
Old 01-30-2007, 11:09 PM
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levansic levansic is offline
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Quote:
Originally Posted by neverquit View Post
...On the other hand, lets get finding those fellas who did it on the Longs and ask them.
Well, I tracked one down in Mike Melville. He didn't build it, but he tested one that had a 1" rear wheel movement and he said it had a much longer takeoff roll than the plans-built Long EZ. The others he mentioned had a nasty accident off the end of a runway when they failed to unstick the mains from the ground.

-- EDIT --
I couldn't find a record of this accident in the Canard Pushers, so I'll pry for more details on the accident from Mike tomorrow.

-- Len
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Last edited by levansic : 01-31-2007 at 01:34 AM.
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  #50  
Old 01-31-2007, 12:23 PM
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Fun stuff

My thoughts have grown slightly

A move mains back 4 to 6 inches
B increase Canard by 4 to 6 inches
C raise nose by 1 inch.

What does that give you - a plane that is not toyish. In my opinion, having to worry about the nose always being lowered when the plane is not occupied makes it toyish.

Oh yeah

D adjustable prop

The Oh yeah really makes allot of sense in the Cozy as it seriously decreases required runway length

I am not an "aviator" any more than i am a "car driver" or a "truck driver" altho i use all when needed.

the more "you have to remembers" we can design out, the more planeish and the less toyish the plane becomes
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  #51  
Old 01-31-2007, 03:50 PM
Phil Kriley Phil Kriley is offline
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Will your "improvements" destroy the safety built into the design? With a larger canard/elevator, won't you be able to get the wing to exceed the critical AOA? Adding a constant-speed prop will make the tail that much heavier - you'll have to move your gear back another 10 inches...

Raise the nose an inch? So that you can improve your chances of landing on the nosegear instead of the mains? Hmmmmm...doesn't sound like such a good idea to me.

I'm not an engineer, and do not desire to be a test pilot. Smarter men than me designed this plane, and I intend to build it as designed with the hope that it will fly as designed.
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  #52  
Old 01-31-2007, 04:01 PM
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Phill - I was surprised to learn that many did not cut off the 6 inches from thier canard, just moved the allowable rear CG forward, surprised the heck outa me, but that just seems to be how it is done.

Some here have and are putting the larger canards on, mine is larger in the other way by 1/4 inch.

Same with the inch on the nose gear and if you are landing that flat, well - better correct your landing procedure.

As far as weight of the prop, for me a non event, you want performance - you pay the price.
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dust

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  #53  
Old 01-31-2007, 06:03 PM
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John Slade John Slade is offline
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Quote:
Will your "improvements" destroy the safety built into the design?
Destroy might be the wrong word. "Remove" would be the one I'd use. This would be an entirely NEW design which would not come with the comforting feeling that it's been done before and worked for everyone else.

The suggested changes might work well, or they might not. Perhaps someone will implement them one day. Perhaps not. In the meantime it's entirely pointless speculating on guesswork.

Quote:
Fun stuff
Not really. I think it's kinda boring going around the same old circles. Until someone does this, and tests it VERY VERY carefully, or maybe an trained aeronautical engineer runs the numbers, at best it's a waste of characters on the screen.

Quote:
My thoughts have grown slightly
That would be a matter of opinion.

Quote:
A move mains back 4 to 6 inches
B increase Canard by 4 to 6 inches
C raise nose by 1 inch.
And these rough guestimates came from where. No - don't tell me. Let me guess.

Quote:
just seems to be how it is done.
A very small minority have increased the plans canard length and flown. This does NOT mean that this is now the accepted norm.

What on earth are you trying to achieve, Mike? Discussion for the sake of discussion?

Any new builders reading this - PLEASE do NOT give these wild unproven guesses at a new design any credence.
confirm any proposed modifications with a consensus of experienced builders and flyers.
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  #54  
Old 01-31-2007, 06:31 PM
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karoliina karoliina is offline
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Quote:
Originally Posted by Phil Kriley View Post
Will your "improvements" destroy the safety built into the design?
...
Adding a constant-speed prop will make the tail that much heavier
...
do not desire to be a test pilot.
...
Which safety and built by who and how? I thought Nat used saw.

Well, my building supervisor (analoguous to FAA inspector in your terms) thinks that it would ruin a high performance aircraft to not use a constant speed propeller on it and he don't approve our plane if it is equipped with a el-cheapo two blade fixed wood prop. And based on my own experience with flying a plane with a CS prop (MT Propeller), it really makes a _huge_ difference, especially in takeoff and approach/landing performance. However YMMV.

BTW. Every experimental builder becomes a test pilot unless he or she hires a commercial test pilot to do the job, otherwise the aircraft is unproven and not safe to fly and depending on the rules in the country, it might even be illegal (e.g. in Finland it would), if somebody else like Nat, Marc etc. has tested their planes, it doesn't generalize to everybody's planes so others could skip the testing phase alltogether. Also the CG may vary depending on how much epoxy you pour on it which engine variant you bolt on, so the weight and balance must be measured too, you can't just trust that it will get right if you do as specified on plans, it can still go wrong. So if you have to do this anyway, the additional weight of CS prop should be non-issue as you know how to compensate it with additional weight on the nose. What happens is that you have few lbs more weight, but CG still on same position, it don't really affect how the nose lifts up other than that it happens a lot sooner with a CS prop because the acceleration to the speed the canard needs to provide enough lift to lift up the nose builds up faster which results shorter roll on runway which results more marginal to the end of runway and more marginal to cancel the takeoff if something goes wrong.
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  #55  
Old 01-31-2007, 09:23 PM
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Quote:
Originally Posted by John Slade View Post
Destroy might be the wrong word. "Remove" would be the one I'd use. This would be an entirely NEW design which would not come with the comforting feeling that it's been done before and worked for everyone else.

The suggested changes might work well, or they might not. Perhaps someone will implement them one day. Perhaps not. In the meantime it's entirely pointless speculating on guesswork.

Not really. I think it's kinda boring going around the same old circles. Until someone does this, and tests it VERY VERY carefully, or maybe an trained aeronautical engineer runs the numbers, at best it's a waste of characters on the screen.

That would be a matter of opinion.

And these rough guestimates came from where. No - don't tell me. Let me guess.

A very small minority have increased the plans canard length and flown. This does NOT mean that this is now the accepted norm.

What on earth are you trying to achieve, Mike? Discussion for the sake of discussion?

Any new builders reading this - PLEASE do NOT give these wild unproven guesses at a new design any credence.
confirm any proposed modifications with a consensus of experienced builders and flyers.
For me learning what is real and opening up my eyes to reality is fun. These items are proven, every single one of them. I enjoy learning, I enjoy more clearing the fog from my eyes.

For example, was it or was it not a choice by flyiers at the time when Nat shortened the canard by 6 inches a required change to lop off 3 inches per side of canard or was it a choice of that OR making a further limit to the rear CG. I say further cause there is always a limit to the CG. After pondering this I understand why Nat suggested extending my elevators 1/4 inch along thier length.

Many vocal "experienced builders and flyers" feel that the problems i see just take training to solve, prop strikes from nose too high take off or landing, plane tipping if you wonder off for a moment when gear extended or push the plane incorrectly.

open or close your eyes, the choice is always yours.
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dust

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  #56  
Old 01-31-2007, 09:48 PM
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levansic levansic is offline
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Quote:
Originally Posted by Dust View Post
A move mains back 4 to 6 inches
B increase Canard by 4 to 6 inches
C raise nose by 1 inch.
D adjustable prop
A little back of the envelope hand waiving is in order. Point by point.

A) Moving mains will cause higher canard loading for takeoff. With a plans canard, you have the possibility of not leaving the ground.

B) Lengthening the canard could overcome (A) for the take-off condition, as the loading would decrease. Unfortunately, once you leave the ground, the increased canard lift would require a forward shift in the CG envelope. Load the front up with ballast for every flight to stay in the safe zone. More weight, less performance. The main wing area could be increased in size to compensate. Better do a lot of math and testing with a long runway
and a parachute. As Melvill noted, this is what Velocity did, and it caused their deep stall problems. It took lots of modifications and testing to return the design to a more safe flight regime.

C) Why not increase the canard incidence angle? Longer front gear requires a longer wheel well, which requires structural changes to bulkheads and possibly the instrument panel. This is not a trivial change.

D) Adjustable prop adds weight to the rear, shifting the plane's native CG rearward. You need more ballast up front for this. If (A) is implemented, one of these may introduce you to the airport's fence a bit quicker than a fixed pitch prop. I can't say too much against the adjustable prop, as I'm looking into using one myself, other than that they are expensive and that you have to pay close attention to their condition. As Marc's recent in-flight event illustrates, no prop is maintenance free.

That's enough hand waiving for now, as I don't have any concrete numbers for the impact of any of these.

-- Len
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  #57  
Old 01-31-2007, 11:02 PM
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just a small back of the envelope - the plans length canard is 6 inches wider with a 1 inch, i believe, less allowable rear CG

just a different look at reality - was the canard change mandatory for cozy's flying at the discovery of the deep stall problem, i think not, i think that it was just required to change the cg envelope.

a 1" longer nose wheel fits without a bulkhead change, takes a minor heat duct change - others that have done it can pipe in and say what they have done.

I don't know of any that have changed the angle of incidence, i would not think of it, i like to keep my thoughts to what has been done.
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dust

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  #58  
Old 01-31-2007, 11:25 PM
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Clutch Cargo Clutch Cargo is offline
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Exclamation Let them snarf cake....

I sure hope nobody takes this forum as gospel as to the modifications they conceive and are in need of abetting. Extrapolating works best when all known data is analyzed first.
I see where Mike wants to go with this, and it's not a totally crazy desire to know your front wheel is going to stay on the ground all of the time, I've been thinking about that as well. Steerable nose wheel, carbon fiber retracts non-JD produced, and other mods I draw on CAD makes me realize that quite a bit of engineering went into this design, and not just to make it flyable, but to make it safe and easier to build.
I honestly believe there is a way to do it (what Mike wants to do), although I also believe there is going to be a trade-off, in physics there always is a trade-off.
In court (Chris might back me up on this) any testimony about anything said by a third party can be "hearsay" (what someone esle said) and can be disallowed and for a good reason. It doesn't matter what someone says someone else (rather popular) says, because there is a good chance it is going to be diluted and convoluted and slightly inaccurate or slightly skewed to favor the one relating the information.
I do however, trust what John Slade says because I have seen and heard him and his airplane. I know his judgement is sound on matters especially on matters that I agree on as well. I trust Marc because everytime I say something stupid where he corrects me, I dig in my ancient AE books and find he has been right every time! There is a good reason for that. But saying this should not convince anyone of anything....it is merely words on a screen.
On the other hand, a dream is a dream until it flies. Then it is a realty. I say; Let Mike dream. If the dream doesn't come true, he is smart enough to figure out why. Meanwhile he keeps the rest of us from going stagnant. Also, proving again to ourselves what we want from the plans we bought.
We can learn from the right way and the wrong way. The wrong way only takes a few seconds. The right way takes a few years. But, in the end, we decide the value of the information we have gleaned from this forum. How we decide to use it, is entirely up to each one of us.
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  #59  
Old 02-01-2007, 07:36 AM
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John Slade John Slade is offline
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Quote:
what Mike wants to do
What bothers me is that Mike has no intention of doing these mods himself. He just seems to want others to think that they're "ok" and "no big deal".

There's nothing wrong with offering up proposals for peer review, thinking outside the envelope or doing calculations on the back of it. Mike doesn't even have an envelope. He just throws this stuff out there for the fun of being shot down and / or because he can't put an idea down once he's picked it up.

I've known people who argue intensely without reason, but keep the argument going until everyone else gets bored with it, then call it a victory. That technique wont work here. I think there's a word for it. I notice that Marc and others that know tend to give up after a while, and I don't blame them. Many experienced builders (Buly, for example) just leave the forum because its not worth the trouble.

Arguing the engineering principals behind a new suggested mod is fine and welcomed (at least by me). Just arguing is a waste of everyone's time and costs the forum good people and their valuable knowledge.
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  #60  
Old 02-01-2007, 09:03 AM
Hennie Engelbrecht Hennie Engelbrecht is offline
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Default open or close your eyes, the choice is always yours.[/QUOTE]

Many vocal "experienced builders and flyers" feel that the problems i see just take training to solve, prop strikes from nose too high take off or landing, plane tipping if you wonder off for a moment when gear extended or push the plane incorrectly.


Mike,

why would you want to change critical flight criteria for the sake of "on the ground" static, non flight related functionalities.

If you want to prevent it from tilting, add an extendable support at the back. That would mitigate your need without setting you off on the R and D road..

Hennie
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