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View Poll Results: What type of gear will (or would) you install
Featherlite Strut 47 45.19%
Infinity Retracts 43 41.35%
Aerocad fixed gear 2 1.92%
Other retract system 12 11.54%
Voters: 104. You may not vote on this poll

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  #136  
Old 08-27-2007, 08:43 AM
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neverquit neverquit is offline
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Default Re: Retracts or fixed gear?

Anyone seen a retract made of standard off the shelf struts? Seems it would be an economical alternative since the Drybread struts are hard to come by.
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  #137  
Old 08-27-2007, 02:53 PM
chasingmars chasingmars is offline
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Default Re: Retracts or fixed gear?

Regarding slipping the Cozy...

Quote:
Originally Posted by Marc Zeitlin View Post
Don't deploy them equally. They're not digital - there's space between "ON" and "OFF".
I've been thinking about this a bit...

Now, I've never flown a canard, I'm a low time (55 hr) student pilot, so this is coming from ignorance, but...

What I've been taught for slips (this is on a Diamond Katana), is that it is essentially a digital maneuver, you put in full rudder, then compensate with the aileron to get your track where you need it. Rational my instructor gave for this, is that this way you're only controlling one variable (aileron) vice two, which is much easier. This makes sense, and he's told me a few time as I've a tendency to make partial slips, the Katana comes down fast in a full slip. Maybe this is just a matter of mastering the basics (full slips) first and learn the finer points (partial slips) later.

But that's kinda just background to my question, I guess, what I'm wondering is why do you not get more descent rate by only deploying only the one rudder, which gives more slip, and therefore a steeper decent, given that the drag from slipping seems to be mentioned as more effective than "speed braking" the rudders? Or is the first bit of rudder deployment just more effective than the last bit of slip?
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  #138  
Old 08-27-2007, 03:46 PM
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Default Re: Retracts or fixed gear?

Quote:
Originally Posted by neverquit View Post
Anyone seen a retract made of standard off the shelf struts? Seems it would be an economical alternative since the Drybread struts are hard to come by.
The Berkut drawings include the construction of the main gear struts. All carbon fiber as I recall.
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  #139  
Old 08-27-2007, 03:50 PM
Marc Zeitlin Marc Zeitlin is offline
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Default Re: Retracts or fixed gear?

Quote:
Originally Posted by chasingmars View Post
I've been thinking about this a bit...
Danger, Will Robinson, Danger!! :-).

Quote:
Originally Posted by chasingmars View Post
Ihat I've been taught for slips (this is on a Diamond Katana), is that it is essentially a digital maneuver, you put in full rudder, then compensate with the aileron to get your track where you need it.
Every plane is different - some will run out of rudder before running out of aileron, and some will run out of aileron before running out of rudder. Which category you're in will determine which you max. out and which you modulate.

Quote:
Originally Posted by chasingmars View Post
... why do you not get more descent rate by only deploying only the one rudder, which gives more slip, and therefore a steeper decent, given that the drag from slipping seems to be mentioned as more effective than "speed braking" the rudders? Or is the first bit of rudder deployment just more effective than the last bit of slip?
Well, here's what I usually do for slips (understanding that I have NOT done a complete analysis of all possible slip modes, so this might not be the most efficient method of losing altitude).

Realizing that I'm high, I drop the landing brake. If I'm still high, I'll push both rudders. If I'm still high, I'll crank in some aileron in the direction I want to slip (usually right wing low, for no particular reason - maybe it's because I'm left handed) and then modulate the right rudder to keep me on track. So basically I'm holding full left rudder and modulating the ailerons and right rudder to maintain the slip.

Would it be better to get off the right rudder and just modulate ailerons? Maybe. Since I'm starting from a place where both rudders are deployed, there's an extra degree of freedom with the two rudders that you don't have with a standard aircraft, and I may be using the begin state of my slip to determine what I do, and that may not be optimal. Like I said, I haven't done the experiments to determine that. It's all going to be within 100 fpm or so, though, and that's never the gating factor as to whether I can get down or not - if it is, it's time to go-round (and I've never gone around in the COZY, in well over 500 landings, even on the shortest of runways or the gustiest of days).
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  #140  
Old 08-27-2007, 04:15 PM
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Default Re: Retracts or fixed gear?

The slip is not the same in all aircraft as Marc pointed out. I was shocked to learn that a slip in a cessna with full flaps is flirting with disaster. Not good at low altitude.

It's possible to cutoff enough airflow to destabilize the tail with nasty results. Now at altitude it's not such a big deal.

A skydiver's joke to pull on the pilot of a cessna jump plane:
When everyone is stacked in the door and hanging off the wing strut, the last guy motions for 5 degrees left. The jumpers have already cutoff the airflow to the starbord side of the tail and a little rudder action is all it takes to cutoff enough air on the port side. The result is the tails stalls and we all jump leaving the pilot to figure it out.

They had ways of paying us back.
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  #141  
Old 08-27-2007, 04:31 PM
Marc Zeitlin Marc Zeitlin is offline
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Default Re: Retracts or fixed gear?

Quote:
Originally Posted by TMann View Post
... I was shocked to learn that a slip in a cessna with full flaps is flirting with disaster. Not good at low altitude.
OWT. What Cessna says, in 172's with 40 degrees of flap capability, is that "slips with flaps are not recommended". They are NOT prohibited. There has been extensive discussions of this on numerous rec.aviation.* newsgroups. There is no disaster in slipping with flaps, either with 30 degrees or 40 degrees of flaps. Unshock yourself :-).

Also realize that MUCH of what you hear from CFI's regarding aerodynamics, either in general or specific to individual aircraft, will be complete nonsense. Most are shockingly ignorant of aerodynamics, as are most pilots. I can't tell you how many pilots don't know the difference between IAS, TAS, and GS, not to mention DA and PA, and god forbid you try to get any of them to tell you how lift is developed. Don't get me started.

Quote:
Originally Posted by TMann View Post
It's possible to cutoff enough airflow to destabilize the tail with nasty results. Now at altitude it's not such a big deal.
No, it isn't. Not with flaps anyway - maybe with jumpers standing on the strut, but not with flaps. What the flaps do is mildly disrupt the airflow over the tail, and you get some small oscillations. Nothing dangerous. And then ONLY with 40 degrees - not 30 degrees.
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  #142  
Old 08-27-2007, 04:49 PM
chasingmars chasingmars is offline
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Default Re: Retracts or fixed gear?

Quote:
Originally Posted by Marc Zeitlin View Post
Also realize that MUCH of what you hear from CFI's regarding aerodynamics, either in general or specific to individual aircraft, will be complete nonsense. Most are shockingly ignorant of aerodynamics, as are most pilots.
Don't I know it... Moreover, most aren't interested in discovering this! After I learned that part, I think my tongue was bleeding by the time I finished the aero portion of my ground school. I was quite amazed at the creativity of some of the explanations.

How GPS functions is another one that borders on hilarity when taught in ground school.
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  #143  
Old 08-27-2007, 04:51 PM
chasingmars chasingmars is offline
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Default Re: Retracts or fixed gear?

Quote:
Originally Posted by Marc Zeitlin View Post
Well, here's what I usually do for slips (understanding that I have NOT done a complete analysis of all possible slip modes, so this might not be the most efficient method of losing altitude).
(snip)

That makes sense, thanks for the explanation.

A bit more complicated than the Katana, which is essentially, 1. Choose a rudder and press it to the floor 2. correct track with airleron 3. When you've dropped enough altitude, recover by releasing pressure to coordinated flight. But I guess that's why the Katana is a primary trainer, and (at least in Canada) the Cozy is classed as a high performance aircraft with a 200 hr minimum.
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