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601HD wings modified to 23'

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rmallett(at)tampabay.rr.c
Guest

Posted: Wed Mar 28, 2007 11:03 am Post subject: 601HD wings modified to 23'

Hi All,

  

 I have a partially completed 601HD kit. The  first owner ordered modified 23' wings instead of the original 27'  wings.

 It is important when completed this  kit comply with LSA requirements. Personnel at Zenith feel there will  not

 be a problem but to lessen concern vortex  generators could be added to the wings lowering the stall speed

 by 4 to 6 mph (conservative estimate). Any  thoughts to assure LSA compliance especially as it  relates

 to stall or cruise speeds would be greatly  appreciated.

 Ray

  

   [quote][b]

n801bh(at)netzero.com
Guest

Posted: Wed Mar 28, 2007 12:36 pm Post subject: 601HD wings modified to 23'

Clipping the wings 5 feet will have a huge impact on stall speeds. IMHO 

do not archive

Ben Haas

N801BH

www.haaspowerair.com



-- "ray" <rmallett(at)tampabay.rr.com> wrote:

 Hi All,

  

 I have a partially completed 601HD kit. The first owner ordered modified 23' wings instead of the original 27' wings.

 It is important when completed this kit comply with LSA requirements. Personnel at Zenith feel there will not

 be a problem but to lessen concern vortex generators could be added to the wings lowering the stall speed

 by 4 to 6 mph (conservative estimate). Any thoughts to assure LSA compliance especially as it relates

 to stall or cruise speeds would be greatly appreciated.

 Ray

  

[quote]



====================================

">http://www.matronics.com/Navigator?Zenith-List

====================================

tronics.com

====================================



[b]

rickpitcher

Joined: 27 Feb 2007
Posts: 76

Posted: Wed Mar 28, 2007 1:08 pm Post subject: 601HD wings modified to 23'

---

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Wed Mar 28, 2007 1:15 pm Post subject: Re: 601HD wings modified to 23'

That basically makes it an HDS. The Zenith site says the HDS has a stall speed at 1050 lbs of 54mph  and a top speed of 150mph.



http://www.zenithair.com/zodiac/601-hds.html



The top speed isn't a problem because even if the plane can do it you could adjust the prop so it can't.



The LSA max stall speed is 50 mph. Can you shave off 4 mph with vortex generators? I don't know. But remember that stall speed is at 1050 lbs. that is awful low compared to the XL.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

rickpitcher

Joined: 27 Feb 2007
Posts: 76

Posted: Wed Mar 28, 2007 1:53 pm Post subject: 601HD wings modified to 23'

---

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Wed Mar 28, 2007 4:10 pm Post subject: Re: 601HD wings modified to 23'

Rick, neither of you posts to this thread can be read in the web forum.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

naumuk(at)alltel.net
Guest

Posted: Wed Mar 28, 2007 4:16 pm Post subject: 601HD wings modified to 23'

Ray-

     Look in the archives.  Unfortunately, LSA figures have to be attained as the plane was originally  designed. As I understand it, you can't use VGs to bring an airframe into LSA  requirements.

     I would suggest contacting EAA  or (Gulp) the FAA for a final word.

 Bill Naumuk

HDS Fuse/Corvair

Townville, Pa

 [quote]   ---

rickpitcher

Joined: 27 Feb 2007
Posts: 76

Posted: Wed Mar 28, 2007 5:28 pm Post subject: Re: 601HD wings modified to 23'

 	  rickpitcher wrote: 	
		  --- 	


Hi Ray.

I'm glad to see someone trying this. I have an HD that I'm quite pleased 

with, but I've considered clipping a couple feet off each wingtip for higher 

cruise. That fat HD wing is REAL draggy at 115 MPH (cruise with Jabiru 3300 

(at) 108 hp).  I hesitate to clip the wings because I don't want to loose too 

much of the excellent  slow speed with the existing wings.

According to the Zenith specs, the HD stalls at 44 mph. The LSA rules say 

max stall speed is 51 MPH 

http://sportpilot.org/learn/final_rule_synopsis.html so I'm inclined to 

believe you might be OK even without the vortex generators.

Please keep us posted with your results once you get into your flight 

testing.



Rick

http://www.lightflyers.com/birthday

rickpitcher

Joined: 27 Feb 2007
Posts: 76

Posted: Wed Mar 28, 2007 5:29 pm Post subject: Re: 601HD wings modified to 23'

 	  Gig Giacona wrote: 	
		  That basically makes it an HDS. The Zenith site says the HDS has a stall speed at 1050 lbs of 54mph  and a top speed of 150mph.



http://www.zenithair.com/zodiac/601-hds.html



The top speed isn't a problem because even if the plane can do it you could adjust the prop so it can't.



The LSA max stall speed is 50 mph. Can you shave off 4 mph with vortex generators? I don't know. But remember that stall speed is at 1050 lbs. that is awful low compared to the XL. 	


The span would be the same as the HDS: 23'. But the total surface area will 

be greater than the HDS's 98'ft (compared to 130'ft for the stock HD).

The HD wing is a constant chord at 58" instead of the  taper from 58" at the 

root to 34" at the tip, so a clip-wing HD will have more surface area than 

HDS , hence a lower stall speed than the 54mph of the HDS.

I'm not an engineer, just a mechanic... so anyone who has a better 

understanding of the math involved can feel free to correct my aerodynamic 

assumptions.



Interesting idea, I'll be anxious to see how it plays out.

Rick

rickpitcher

Joined: 27 Feb 2007
Posts: 76

Posted: Wed Mar 28, 2007 5:35 pm Post subject: Re: 601HD wings modified to 23'

 	  Gig Giacona wrote: 	
		  Rick, neither of you posts to this thread can be read in the web forum. 	




Thanks Gig. I'll repost from the Web-based site.



Rick

rickpitcher

Joined: 27 Feb 2007
Posts: 76

Posted: Wed Mar 28, 2007 5:53 pm Post subject: Re: 601HD wings modified to 23'

[quote="naumuk(at)alltel.net"]Ray-

     Look in the archives.  Unfortunately, LSA figures have to be attained as the plane was originally  designed. As I understand it, you can't use VGs to bring an airframe into LSA  requirements.

     I would suggest contacting EAA  or (Gulp) the FAA for a final word.

 Bill Naumuk

HDS Fuse/Corvair

Townville, Pa

  	  Quote: 	
		     --- 	




I don't think that's correct Bill. 



From http://sportpilot.org/learn/final_rule_synopsis.html 

"The FAA defines a light-sport aircraft as an aircraft, other than a helicopter or powered-lift that, since its original certification, has continued to meet the following: " <snip>



If the plane hasn't been issued an airwothiness certificate yet you're "good to go". If a plane was previously certified with numbers outside the LSA realm, then you can't re-register the same plane with different numbers (speeds weight, etc) in order to "pencil whip" it into compliance.



Rick

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Thu Mar 29, 2007 5:24 am Post subject: Re: 601HD wings modified to 23'

 	  rickpitcher wrote: 	
		   	  Gig Giacona wrote: 	
		  That basically makes it an HDS. The Zenith site says the HDS has a stall speed at 1050 lbs of 54mph  and a top speed of 150mph.



http://www.zenithair.com/zodiac/601-hds.html



The top speed isn't a problem because even if the plane can do it you could adjust the prop so it can't.



The LSA max stall speed is 50 mph. Can you shave off 4 mph with vortex generators? I don't know. But remember that stall speed is at 1050 lbs. that is awful low compared to the XL. 	


The span would be the same as the HDS: 23'. But the total surface area will 

be greater than the HDS's 98'ft (compared to 130'ft for the stock HD).

The HD wing is a constant chord at 58" instead of the  taper from 58" at the 

root to 34" at the tip, so a clip-wing HD will have more surface area than 

HDS , hence a lower stall speed than the 54mph of the HDS.

I'm not an engineer, just a mechanic... so anyone who has a better 

understanding of the math involved can feel free to correct my aerodynamic 

assumptions.



Interesting idea, I'll be anxious to see how it plays out.

Rick 	




Please note that the original poster said, "The first owner ordered modified 23' wings instead of the original 27' wings." He didn't say anything about cliping the wings. I wasn't aware that Zenith ever offered a shorter wing option other than the HDS wing.

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

Gig Giacona

Joined: 10 Jan 2006
Posts: 1416
Location: El Dorado Arkansas USA

Posted: Thu Mar 29, 2007 6:07 am Post subject: Re: 601HD wings modified to 23'

This is an unfinshed kit so the design issue doesn't really apply. When he finishes it he can call it the SuperDuper LSA Special and not mention either Zenith nor 601. 

 	  naumuk(at)alltel.net wrote: 	
		  Ray-

     Look in the archives.  Unfortunately, LSA figures have to be attained as the plane was originally  designed. As I understand it, you can't use VGs to bring an airframe into LSA  requirements.

     I would suggest contacting EAA  or (Gulp) the FAA for a final word.

 Bill Naumuk

HDS Fuse/Corvair

Townville, Pa

_________________
W.R. "Gig" Giacona
601XL Under Construction
See my progress at www.peoamerica.net/N601WR

larry(at)macsmachine.com
Guest

Posted: Thu Mar 29, 2007 9:53 am Post subject: 601HD wings modified to 23'

Gig,

The vortex generators would lower the stall speed, but each individual 

HDS has to be sorted out on its own stall speed. Some will be slower

and some faster, depending a lot on prop pitch, engine, weight and 

fairings present.  Too many factors to make a single stall speed fits 

all envelope.

Some will make SLA and others won't.



Larry McFarland



Gig Giacona wrote:

 	  Quote: 	
		   

 rickpitcher wrote:

   

> Gig Giacona wrote:

>     

>> That basically makes it an HDS. The Zenith site says the HDS has a stall speed at 1050 lbs of 54mph  and a top speed of 150mph.

>>

>> http://www.zenithair.com/zodiac/601-hds.html

>>

>> The top speed isn't a problem because even if the plane can do it you could adjust the prop so it can't.

>>

>> The LSA max stall speed is 50 mph. Can you shave off 4 mph with vortex generators? I don't know. But remember that stall speed is at 1050 lbs. that is awful low compared to the XL.

>>       

>

> The span would be the same as the HDS: 23'. But the total surface area will 

> be greater than the HDS's 98'ft (compared to 130'ft for the stock HD).

> The HD wing is a constant chord at 58" instead of the  taper from 58" at the 

> root to 34" at the tip, so a clip-wing HD will have more surface area than 

> HDS , hence a lower stall speed than the 54mph of the HDS.

> I'm not an engineer, just a mechanic... so anyone who has a better 

> understanding of the math involved can feel free to correct my aerodynamic 

> assumptions.

>

> Interesting idea, I'll be anxious to see how it plays out.

> Rick

>     

 Please note that the original poster said, "The first owner ordered modified 23' wings instead of the original 27' wings." He didn't say anything about cliping the wings. I wasn't aware that Zenith ever offered a shorter wing option other than the HDS wing.



 --------

 W.R. &quot;Gig&quot; Giacona

 601XL Under Construction

 See my progress at www.peoamerica.net/N601WR





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=103636#103636

klaus(at)utdallas.edu
Guest

Posted: Thu Mar 29, 2007 1:32 pm Post subject: 601HD wings modified to 23'

Hi Ray,



You may want to do the following. First, you can install

vortex generators, if you are so inclined. This is a quick thing to do.

Then, if that does not suffices, you may want to

look into the wing root fairings I have designed, seen at



http://www.utdallas.edu/~klaus/Airplane/wing_root_fairing.html



With those fairings, you surely will satisfy the LSA requirements,

for the following reasons. For my HDS, the fairings reduced the

stall speed at 1020 lbs from 50 KIAS to 42 kts KIAS, which translates

to 58 mph versus 48 mph. My guess is that a 1,100 lbs, which effectively

is the gross limit for my plane due to CG limitations, I would satisfy LSA.

Your clipped wing HD has substantially more wing area than the HDS

since the wing does not taper. Hence, stall speed will be even lower.



BTW, do not worry about top speed going beyond the LSA requirement.

With all the design improvements, my HDS has top speed somewhere

around 132 mph, single pilot, 3,000 ft altitude.

 This is with the 80 hp Rotax 912 UL and

with the propeller pitched so that, in level flight, wide open throttle 

produces

5,400 rpm.



Best wishes,



Klaus

-- 

Klaus Truemper

Professor Emeritus of Computer Science

University of Texas at Dallas

Erik Jonsson School of Engineering and

  Computer Science EC31

P.O. Box 830688

Richardson, TX 75083-0688

(972) 883-2712

klaus(at)utdallas.edu

www.utdallas.edu/~klaus

vgstol(at)bigpond.net.au
Guest

Posted: Thu Mar 29, 2007 2:27 pm Post subject: 601HD wings modified to 23'

What excellent work Klaus!   That's really interesting and significant results.......

  

 Tailwinds always,

 JG

 Do not archive

 [quote]   ---

rickpitcher

Joined: 27 Feb 2007
Posts: 76

Posted: Thu Mar 29, 2007 2:50 pm Post subject: Re: 601HD wings modified to 23'

[quote="Gig Giacona

Please note that the original poster said, "The first owner ordered modified 23' wings instead of the original 27' wings." He didn't say anything about cliping the wings. I wasn't aware that Zenith ever offered a shorter wing option other than the HDS wing.[/quote]



Ahhh... I see. Good point Gig.



The title "601HD wings modified to 23'" had me thinking that these were HD wings modified to 23'. I figured the "modified" part meant that they were clipped. 

This was discussed on http://groups.yahoo.com/group/601_HD-HDS/

a few months ago. I had talked to one of the ZAC guys (Sebastion?) about doing exactlty that: clipping about 2' from the outboard tip of the HD wing, clipping off the outboard panel and ending the wing at the end of the aileron.



Ray, are the ribs all the same size, or are there pairs of progressively smaller ribs as the planform goes outboard? 



Thanks,

Rick

601zv(at)ritternet.com
Guest

Posted: Thu Mar 29, 2007 3:09 pm Post subject: 601HD wings modified to 23'

DITTO!  I'm rethinking my planed XL  fairings!

  

 Do not archive.

 [quote]   ---

naumuk(at)alltel.net
Guest

Posted: Thu Mar 29, 2007 4:18 pm Post subject: 601HD wings modified to 23'

Gig-

    I can't say you're right, but I think you're wrong. EAA said NO.

Bill Naumuk

HDS Fuse/Corvair

Townville, Pa

---

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