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601xl engine out glide ratio

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hallert

Joined: 16 Jun 2009
Posts: 11

Posted: Sat Oct 01, 2011 12:19 pm Post subject: 601xl engine out glide ratio

Does anyone have any glide data on the zodiac? I have tried some engine idle approaches with my AMD 601 XL and find somewhere around 6:1

( about 1000ft/min down at 60 kts) with flap setting not making much difference.



Ted

psm(at)att.net
Guest

Posted: Sat Oct 01, 2011 2:44 pm Post subject: 601xl engine out glide ratio

Hi Ted,



I'm in the middle of flight testing my XL and have found only slightly 

better glide performance - perhaps 8:1.  Yours might be a little bit 

worse because of the heavy engine.  This gets you twice - heavier empty 

weight and more forward CG.  My XL is equipped with a Jabiru 3300A 

engine which should weigh about 100 pounds less than the O-200 installed.



The good news is it is a lot easier to land an airplane with either 8:1 

or 6:1 than the 14:1 or so I got from my Tecnam Echo Super.  That plane 

was difficult to get to come down at all.



You might do a little bit better if you go slower - perhaps 50 or 55 knots.



Paul

Camas, WA

XL - 17 hours into phase I flight test.



On 10/1/2011 1:19 PM, hallert wrote:

 	  Quote: 	
		   



 Does anyone have any glide data on the zodiac? I have tried some engine idle approaches with my AMD 601 XL and find somewhere around 6:1

 ( about 1000ft/min down at 60 kts) with flap setting not making much difference.



 Ted





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=353714#353714

hallert

Joined: 16 Jun 2009
Posts: 11

Posted: Sun Oct 02, 2011 6:41 am Post subject: Re: 601xl engine out glide ratio

Paul,

You're right about the engine weight. The other strange behavior I have noticed is that slips have practically no effect on the descent rate unlike 

any other aircraft I have flown. Have you noticed this?



Ted

psm(at)att.net
Guest

Posted: Sun Oct 02, 2011 7:05 am Post subject: 601xl engine out glide ratio

Hi Ted,



I haven't tried slips yet.  The plane drops so nicely with full flaps I 

never thought of slips.



I have tried to stall my plane and never really got a break.



I've been spending most of my time working on engine cooling issues and 

flight control problems.  I'm about the start spending some real time 

just flying the plane and trying to get good at landing it.



The biggest flight control problems have been insufficient trim to trim 

out full flap configuration and a need to hold left rudder to get it to 

fly straight.  I fixed the trim by adding a fixed tab to the motorized 

one.  The rudder "Trim" problem has been fixed by adjusting the rudder 

cables.



My last change (I hope) is to add a small fin on the bottom rear of the 

fuselage.  I have been unhappy with the yaw stability and hope to 

improve it a little bit.  Especially in turbulence, the nose seems to 

wander from side to side instead of finding a good position and staying 

there.  I can't imagine why Chris built his planes without a vertical 

stabilizer, but this seems like the price for that choice.  I don't know 

of any other planes with this rudder configuration.



Paul



On 10/2/2011 7:41 AM, hallert wrote:

 	  Quote: 	
		   



 Paul,

 You're right about the engine weight. The other strange behavior I have noticed is that slips have practically no effect on the descent rate unlike

 any other aircraft I have flown. Have you noticed this?



 Ted





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=353780#353780

psm(at)att.net
Guest

Posted: Sun Oct 02, 2011 3:10 pm Post subject: 601xl engine out glide ratio

Hi Ted,



I just took a long look at the Zodiac XL fuselage.  I wanted to consider 

my new fin (which doesn't work) to get some yaw stability.  I also 

considered your comments about slips having little impact.



The Zodiac XL has a very funny shape.  Because of the flat sides and the 

angle they make to the tail and the way the front of the cabin is shaped 

there seems to be no yaw stability at all built into the fuselage.  When 

you slip there is no significant change in the cross section of the 

fuselage that hits the air flow.  This changes once you get the tail out 

further than the widest point at the cabin center (shoulder area for 

passengers), but that would be a very deep slip indeed.



I wanted to add some yaw stability, but my first attempt to add a fin on 

the bottom of the fuselage didn't work.  In order to get a significant 

"Height" the fin will hit the ground when the nose is raised.  This 

would be particularly noticeable when doing a full stall landing.



I took a look around the airport at other planes, and most of them 

(particularly TC'd ones) have an extra fin that goes from the front or 

middle of the fuselage length up to the front of the fixed fin in the 

tail.  I suspect adding such a fin to the XL might give it some 

stability but this looks like it would be a big job.  The top of the 

rear fuselage has very little strength, and this would probably need to 

be beefed up to support air loads to the side of the fuselage.  And, of 

course, the XL design as drawn has no vertical stabilizer at all.



If you compare the Piper Sport to the Zodiac XL you will see the biggest 

change is in the addition of a vertical stabilizer.  This plane was 

designed by CZAW and appears to use many parts from the Zodiac XL they 

used to sell into the European market.



I hope somebody else has looked at this with a smarter eye than mine and 

come up with something that works.



Paul

Camas, WA



On 10/2/2011 7:41 AM, hallert wrote:

 	  Quote: 	
		   



 Paul,

 You're right about the engine weight. The other strange behavior I have noticed is that slips have practically no effect on the descent rate unlike

 any other aircraft I have flown. Have you noticed this?



 Ted





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=353780#353780

mhubel

Joined: 05 Sep 2009
Posts: 141

Posted: Sun Oct 02, 2011 5:32 pm Post subject: 601xl engine out glide ratio

Ted,

     My CH601LX may be a bit different. It is a Jabiru 3300 powered and 

has no wheel covers at this time but otherwise it should  be somewhat 

similar.

     I show a best glide of 65 mph IAS with a sink rate of about 700 

feet per min for about a 8:1 ratio. This is at gross, while I have not 

measured it carefully, I think it is about 500-600 feet per min sink 

rate with no passenger and part fuel.  I have not tried it with the prop 

stopped, that would probably increase the ratio a bit.

     I find that at gross and a 75 mph IAS, I can see a sink rate of 

1000 feet per min with full flaps and almost 1500 in a slip plus flaps. 

I do find that slips should not be done below 70 mph IAS or one can have 

poor aileron control.

     I also did run out of trim at full flaps and have put in a spring 

on the elevator to neutralize its weight. This made the trim range just 

make it to full flaps.

     I believe you said that you had observed a tendency to roll to one 

side when near stall. I originally had that problem. It turned out that 

trailing edge of the right wing was a few mm too low. There had been a 

measurement error that propogated through construction. This may have 

nothing to do with your observations but it might be worth checking.

     While I agree that this is not as stable as a high wing plane, I 

have not found it to be unusually unstable. I don't find it to be too 

much different from a PA24 (Piper Comanche) I once had. The PA24 was 

very unforgiving if you let it drift on its own.



Mark Hubelbank

Ch601XL-B

Jabiru 3300

Sensenich adj prop

Rotec TBI-40-3

145 Hours airframe

_________________
Mark Hubelbank
N708HU
CH601XL
Jabiru 3300
Rotec TBI 40-3 carb
Sensenich ground adj prop.
240 hr TAF
Pictures at photo.hubbles.com

hallert

Joined: 16 Jun 2009
Posts: 11

Posted: Mon Oct 03, 2011 6:36 pm Post subject: Re: 601xl engine out glide ratio

Paul and Mark,

Thanks for your inputs. I too have insufficient up trim when flying by

 myself but with a passenger and less fuel it has just enough. I also had to 

"trim" the rudder by adjusting the cables to center the ball in cruise. Have

 not noticed the yaw instability you mention Paul. Seems much better than

an Allegro which I flew 6 years ago that seemed totally unstable in yaw.



Ted

psm(at)att.net
Guest

Posted: Mon Oct 03, 2011 7:57 pm Post subject: 601xl engine out glide ratio

Hi Ted,



Rather than unstable, I would call the yaw behavior of the XL astable.  

It will stay where you put it, but it won't find the best position in 

yaw, i.e. it won't straighten itself out.  If you kick the ruder the yaw 

position will change and stay in the new position.  If it were unstable 

it wouldn't stay in any position but would constantly wander around.



I think this also explains your comment about slips not doing any good 

to adjust landing approaches.  Moving the tail from about 2 feet left of 

center to the same amount right of center doesn't really change the 

cross-section presented to the relative wind.  There just isn't anything 

significant on the plane that is lined up with the vertical axis while 

moving forward.  It is only when the tail displacement exceeds the 

widest part of the fuselage (the shoulder area for passenger and pilot) 

that the cross section changes.



I have been really miserable over this "Feature" since I discovered it a 

week or two ago.   At first I wanted to add some sort of vertical fin to 

fix the problem but after an attempt to do this I decided I just don't 

have the engineering skill needed for a change this big.  Today I added 

a bump on the top/front of the engine cowl in the correct position to 

help line up the nose with the runway on landing.  I haven't yet tried 

out the new feature.  The rains have started here in the Pacific NW rain 

forest and I have no clue when there will be sufficient flying weather 

for the test.



Paul

XL in flight test.



On 10/3/2011 7:36 PM, hallert wrote:

 	  Quote: 	
		   



 Paul and Mark,

 Thanks for your inputs. I too have insufficient up trim when flying by

   myself but with a passenger and less fuel it has just enough. I also had to

 "trim" the rudder by adjusting the cables to center the ball in cruise. Have

   not noticed the yaw instability you mention Paul. Seems much better than

 an Allegro which I flew 6 years ago that seemed totally unstable in yaw.



 Ted





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=353970#353970

PatrickW

Joined: 27 Oct 2006
Posts: 380
Location: Fort Worth, Texas

Posted: Tue Oct 04, 2011 7:44 am Post subject: Re: 601xl engine out glide ratio

Would this improve crosswind landing behavior?



- Pat

psm(at)att.net
Guest

Posted: Tue Oct 04, 2011 8:37 am Post subject: 601xl engine out glide ratio

Hi Pat,



I don't think so.



The B-52 had cross-wind landing gear that allowed the plane to land with 

a crab while the wheels went straight down the runway.  That seems like 

a different think from the XL.



The XL will fly somewhat sideways with the wings level, but the wheels 

always point in the same direction as the nose of the plane.  This seems 

to me to make it more difficult to get the wheels going down the runway 

while landing.  You still need to tip the wings into the wind to get it 

flying straight down the runway in a crosswind.   A crab will only help 

you, in this case, if you have engine power to pull the plane to the side.



I could easily be wrong about this question.  I still have a lot of 

testing to do to be sure of anything.



Paul

XL in phase I flight test.



On 10/4/2011 8:44 AM, PatrickW wrote:

 	  Quote: 	
		   



 Would this improve crosswind landing behavior?



 - Pat



 --------

 Patrick Hoyt

 601XLb/Corvair

 N63PZ - 99.999% done....





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 http://forums.matronics.com/viewtopic.php?p=354019#354019

hallert

Joined: 16 Jun 2009
Posts: 11

Posted: Tue Oct 04, 2011 4:13 pm Post subject: Re: 601xl engine out glide ratio

Paul,

Does your nosegear have a detent (notch  that a pin on the strut drops into when weight is released)? This for me basically locks the rudder when in flight. I only need to push right rudder on climb out.



Ted

psm(at)att.net
Guest

Posted: Tue Oct 04, 2011 4:30 pm Post subject: 601xl engine out glide ratio

Hi Ted,



Yes I do.  However, it doesn't seem to center properly.  I need to kick 

the rudder pedal to get the plane to fly straight forward.  If you look 

at the geometry of the rudder and the fuselage side in front of the 

rudder you may see that there is a bit of play in the rudder position 

before it actually moves the tail one way or another.



Paul



On 10/4/2011 5:13 PM, hallert wrote:

 	  Quote: 	
		   



 Paul,

 Does your nosegear have a detent (notch  that a pin on the strut drops into when weight is released)? This for me basically locks the rudder when in flight. I only need to push right rudder on climb out.



 Ted





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=354065#354065

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