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pdukor1(at)tampabay.rr.co
Guest

Posted: Mon Jan 22, 2007 5:51 am Post subject: Thoughts on Upgrades

I am new to the list, but was impressed by the plane at the Sebring 

Show last weekend. in any case how about a constant speed prop like 

the Airmaster (or whatever brand) which is already set up for the 

3300? Seems to me the plane and pilot win in better fuel economy, 

longer range and improved performance numbers from takeoff to landing. 

Yeah, it is more money, I know, but I think it is the missing link to 

make this a very happy rocket.



Paul dukor

Sarasota, Florida

pete(at)flylightning.net
Guest

Posted: Mon Jan 22, 2007 6:47 am Post subject: Thoughts on Upgrades

We've tried the Airmaster.  To our surprise it resulted in a substantial

decrease in cruise performance.  The explanation was that the Warp Drive

blades are great for speeds up to 140 knots but hit the wall above that.  



We are hoping that Sensenich will get their in flight adjustable up and

running soon with the ZK blade profile that works so well with the 3300

Jabiru.



Pete



--

pdukor1(at)tampabay.rr.co
Guest

Posted: Mon Jan 22, 2007 2:42 pm Post subject: Thoughts on Upgrades

Whoda thunk that!

Thanks for the quick reply since I was still agonizing over it and 

planning a spot on the panel for the controller!

Paul



---

Kayberg(at)AOL.COM
Guest

Posted: Mon Jan 22, 2007 4:30 pm Post subject: Thoughts on Upgrades

My understanding is that constant speed props dont make for faster  airspeeds; only 

  

 1) better takeoff thrust

 2) more weight

 3) more money

 4) possible better economy since it allows for  higher "lugging power"  at lower prop speeds that a prop optimosed for top speed.

  

 If there is a radical difference between stall speeds and top speed,  changing prop speeds can make a difference in fuel burn and keep the prop from  cavitating at static/early takeoff.

  

 But generally you need in excess of 150 hp for it to be worth it....which  is why Piper and Cessna havent messed with putting one on the Cessna 150 or the  Piper 140 Cherokee.

  

 I suspect the best prop deal for the Lightning is simply the lightest  wooden fixed pitch one that will allow

 3300 rpm at WOT.

  

 But I could be wrong.......

  

 Doug Koenigsberg

  

 In a message dated 1/22/2007 5:44:41 PM Eastern Standard Time,  pdukor1(at)tampabay.rr.com writes:

  	  Quote: 	
		  

 	  Quote: 	
		      I am new to the list, but was impressed by the plane at the 

 Sebring    

 Show last weekend. in any case how about a constant speed prop    

 like 

 the Airmaster (or whatever brand) which is already set    up for the 

 3300? Seems to me the plane and pilot win in better fuel    economy, 

 longer range and improved performance numbers from takeoff    to 

 landing. 

 Yeah, it is more money, I know, but I think it    is the missing link 

 to 

 make this a very happy    rocket.

 

	

	


 

  

  [quote][b]

N1BZRich(at)aol.com
Guest

Posted: Mon Jan 22, 2007 4:44 pm Post subject: Thoughts on Upgrades

In a message dated 1/22/2007 7:39:41 P.M. Eastern Standard Time,  Kayberg(at)aol.com writes:

  	  Quote: 	
		     I suspect the best prop deal for the Lightning is simply the lightest    wooden fixed pitch one that will allow

   3300 rpm at WOT.

	


 

  

  [quote][b]

lozhoffman(at)yahoo.com
Guest

Posted: Mon Jan 22, 2007 4:57 pm Post subject: Thoughts on Upgrades

Doug,

Re pitch change allowing faster cruise speeds....



We have a Hoffmann 3 position variable pitch prop on

our 80hp Dimona motorglider. Fine for takeoff, course

for cruise and feather for gliding engine off. The

prop is ground adjustable for pitch variations in any

of these settings.



In fine, the Limbach engine provides a rate of climb

of around 400'-450'fpm (at) 55kts. It would rapidly

approach and exceed red line of 3200rpm (3000-3200rpm

continuous for <5mins permitted on takeoff) beyond

60kts IAS even in climb. 



Resetting the pitch to cruise provides an IAS of

85-90kts (at) 2700rpm. In our case at least the pitch

variation does make a big difference to cruise speed

achieved. 



As an aside, I am amazed at just how small a variation

in pitch there is between our fine and course

settings. Observing the pitch change from outside the

cockpit while someone in it alters the settings, the

change is barely discernable.



Laurie

Sydney  

--- Kayberg(at)aol.com wrote:



 	  Quote: 	
		    

 My understanding is that constant speed props dont

 make for faster  

 airspeeds; only 

  

 1) better takeoff thrust

 2) more weight

 3) more money

 4) possible better economy since it allows for 

 higher "lugging power"  at 

 lower prop speeds that a prop optimosed for top

 speed.

  

 If there is a radical difference between stall

 speeds and top speed,  

 changing prop speeds can make a difference in fuel

 burn and keep the prop from  

 cavitating at static/early takeoff.

  

 But generally you need in excess of 150 hp for it to

 be worth it....which  is 

 why Piper and Cessna havent messed with putting one

 on the Cessna 150 or the  

 Piper 140 Cherokee.

  

 I suspect the best prop deal for the Lightning is

 simply the lightest  wooden 

 fixed pitch one that will allow

 3300 rpm at WOT.

  

 But I could be wrong.......

  

 Doug Koenigsberg

  

 In a message dated 1/22/2007 5:44:41 PM Eastern

 Standard Time,  

 pdukor1(at)tampabay.rr.com writes:

 

 

 >  I am new to the list, but was impressed by the

 plane at the 

 > Sebring  

 > Show last weekend. in any case how about a

 constant speed prop  

 > like 

 > the Airmaster (or whatever brand) which is already

 set  up for the 

 > 3300? Seems to me the plane and pilot win in

 better fuel  economy, 

 > longer range and improved performance numbers from

 takeoff  to 

 > landing. 

 > Yeah, it is more money, I know, but I think it  is

 the missing link 

 > to 

 > make this a very happy  rocket.

 > 

 

 

 

 

 


	


 

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N1BZRich(at)AOL.COM
Guest

Posted: Mon Jan 22, 2007 5:04 pm Post subject: Thoughts on Upgrades

In a message dated 1/22/2007 7:39:41 P.M. Eastern Standard Time,  Kayberg(at)aol.com writes:

  	  Quote: 	
		     I suspect the best prop deal for the Lightning is simply the lightest    wooden fixed pitch one that will allow

   3300 rpm at WOT.

	


 

     I agree with Doug on this.  With the  Lightning's low stall speed, short takeoff roll, and good rate of climb, why not  just put on a prop that will do as Doug says - the lightest wooden fixed  pitch one that will allow 3300 rpm at WOT.  Even with this so  called "cruise / speed prop" on the Lightning the take off roll is still  very short, the climb rate is still very good, and the low stall speed allows  for relatively slow approaches.  Therefore, with the right cruise prop  installed the Lightning can operate out of short runways and still "go like  stink".  In my book, the simplest answer is normally the best plan.   Cheaper, lighter, foolproof.

     And besides, are we really talking about a constant  speed prop (one that uses engine oil as the hydraulic media to keep the prop at  a constant set rpm), or one that has a variable pitch control from the  cockpit and is electrically operated by the pilot to change pitch and might  need lots of attention to keep a constant rpm.  Kind of like the old  electric props on the older Bonanzas.  Sensenich showed me a  pre-production model of this type of hub at Oshkosh two years ago.  It  looked good, but is going to be costly.  I think you will probably be able  to buy four or five Sensenich fixed pitch props for the price of one of  these.  Just my $.02 worth.  Your mileage may vary.

 Blue Skies,

 Buz

  [quote][b]

lozhoffman(at)yahoo.com
Guest

Posted: Mon Jan 22, 2007 5:28 pm Post subject: Thoughts on Upgrades

On re-reading my post it could seem that I'm

advocating a variable pitch prop for the Lightning. On

the contrary, as Buz has well described, I don't

believe the benefits would outway the losses in terms

of cost, weight and complexity. 



I'll be going for a ground adjustable fixed pitch prop

for my Lightning when the time comes for me to order

my kit.

Laurie



 

--- N1BZRich(at)aol.com wrote:



 	  Quote: 	
		    

 In a message dated 1/22/2007 7:39:41 P.M. Eastern

 Standard Time,  

 Kayberg(at)aol.com writes:

 

 I suspect the best prop deal for the Lightning is

 simply the lightest  wooden 

 fixed pitch one that will allow

 3300 rpm at WOT.

 

 

 

     I agree with Doug on this.  With the 

 Lightning's low stall speed, short 

 takeoff roll, and good rate of climb, why not  just

 put on a prop that will do 

 as Doug says - the lightest wooden fixed  pitch one

 that will allow 3300 rpm 

 at WOT.  Even with this so  called "cruise / speed

 prop" on the Lightning the 

 take off roll is still  very short, the climb rate

 is still very good, and the 

 low stall speed allows  for relatively slow

 approaches.  Therefore, with the 

 right cruise prop  installed the Lightning can

 operate out of short runways 

 and still "go like  stink".  In my book, the

 simplest answer is normally the 

 best plan.   Cheaper, lighter, foolproof.

     And besides, are we really talking about a

 constant  speed prop (one that 

 uses engine oil as the hydraulic media to keep the

 prop at  a constant set 

 rpm), or one that has a variable pitch control from

 the  cockpit and is 

 electrically operated by the pilot to change pitch

 and might  need lots of attention 

 to keep a constant rpm.  Kind of like the old 

 electric props on the older 

 Bonanzas.  Sensenich showed me a  pre-production

 model of this type of hub at 

 Oshkosh two years ago.  It  looked good, but is

 going to be costly.  I think you 

 will probably be able  to buy four or five Sensenich

 fixed pitch props for the 

 price of one of  these.  Just my $.02 worth.  Your

 mileage may vary.

 Blue Skies,

 Buz

 


	




 

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Kayberg(at)AOL.COM
Guest

Posted: Mon Jan 22, 2007 6:05 pm Post subject: Thoughts on Upgrades

Laurie,

  

 I know you have already responded to Buz and agree at least in principle  with both of us, but I want to just note that the Limbach is a fine motor, but  different in design....as well as only 2/3 the horsepower of the 3300  Jabiru.   Not to mention it is bolted to a motorglider.  I  suspect the weights of both aircraft are similar, as well as the engines.   In fact, the Limbach may be slightly heavier.

  

 Without that prop, you really cannot motorglide, of course.  Or at  least not nearly as well.

  

 Ryan has been amusing himself lately by shutting the Jabiru engine down and  gliding from significant distances away from the field to see how well he can  glide/practice engine-outs.  It really is quite substantial.    The suggested 17:1 glide ratio is not far off.  I suspect you are closer to  25:1   Our skills dont include soaring just yet, even tho we are near  a good ridge to practice on. 

  

 But It really is about the horsepower.

  

 Doug Koenigberg

  

  

 In a message dated 1/22/2007 8:01:05 PM Eastern Standard Time,  lozhoffman(at)yahoo.com writes:

  	  Quote: 	
		  

Doug,

Re pitch change allowing faster cruise    speeds....



We have a Hoffmann 3 position variable pitch prop on

our    80hp Dimona motorglider. Fine for takeoff, course

for cruise and feather    for gliding engine off. The

prop is ground adjustable for pitch variations    in any

of these settings.



In fine, the Limbach engine provides a    rate of climb

of around 400'-450'fpm (at) 55kts. It would rapidly

approach    and exceed red line of 3200rpm (3000-3200rpm

continuous for <5mins    permitted on takeoff) beyond

60kts IAS even in climb. 



Resetting the    pitch to cruise provides an IAS of

85-90kts (at) 2700rpm. In our case at least    the pitch

variation does make a big difference to cruise speed

achieved.    



As an aside, I am amazed at just how small a variation

in pitch    there is between our fine and course

settings. Observing the pitch change    from outside the

cockpit while someone in it alters the settings,    the

change is barely discernable.



Laurie

Sydney  

---    Kayberg(at)aol.com wrote:

	


 

  

  [quote][b]

lozhoffman(at)yahoo.com
Guest

Posted: Mon Jan 22, 2007 7:29 pm Post subject: Thoughts on Upgrades

Thnx Doug,

The 17:1 glide ratio was one thing that had caught my

eye. Not so much from the perspective of shutting down

and attempting to soar the Lightning but more as

indicative of how aerodynamically clean the airframe

must be. The polar curve for the aircraft would be

interesting though. Anyone have any idea of the

Lightning's best glide speed ie at which speed it

achieves 17:1 and the subsequent sink rate?

Laurie

--- Kayberg(at)aol.com wrote:



 	  Quote: 	
		    

 Laurie,

  

 I know you have already responded to Buz and agree

 at least in principle  

 with both of us, but I want to just note that the

 Limbach is a fine motor, but  

 different in design....as well as only 2/3 the

 horsepower of the 3300  Jabiru.  

  Not to mention it is bolted to a motorglider.  I 

 suspect the weights of 

 both aircraft are similar, as well as the engines.  

 In fact, the Limbach may be 

 slightly heavier.

  

 Without that prop, you really cannot motorglide, of

 course.  Or at  least not 

 nearly as well.

  

 Ryan has been amusing himself lately by shutting the

 Jabiru engine down and  

 gliding from significant distances away from the

 field to see how well he can  

 glide/practice engine-outs.  It really is quite

 substantial.    The suggested 

 17:1 glide ratio is not far off.  I suspect you are

 closer to  25:1   Our 

 skills dont include soaring just yet, even tho we

 are near  a good ridge to 

 practice on. 

  

 But It really is about the horsepower.

  

 Doug Koenigberg

  

  

 In a message dated 1/22/2007 8:01:05 PM Eastern

 Standard Time,  

 lozhoffman(at)yahoo.com writes:

 

 

 Doug,

 Re pitch change allowing faster cruise  speeds....

 

 We have a Hoffmann 3 position variable pitch prop on

 our  80hp Dimona motorglider. Fine for takeoff,

 course

 for cruise and feather  for gliding engine off. The

 prop is ground adjustable for pitch variations  in

 any

 of these settings.

 

 In fine, the Limbach engine provides a  rate of

 climb

 of around 400'-450'fpm (at) 55kts. It would rapidly

 approach  and exceed red line of 3200rpm

 (3000-3200rpm

 continuous for <5mins  permitted on takeoff) beyond

 60kts IAS even in climb. 

 

 Resetting the  pitch to cruise provides an IAS of

 85-90kts (at) 2700rpm. In our case at least  the pitch

 variation does make a big difference to cruise speed

 achieved.  

 

 As an aside, I am amazed at just how small a

 variation

 in pitch  there is between our fine and course

 settings. Observing the pitch change  from outside

 the

 cockpit while someone in it alters the settings, 

 the

 change is barely discernable.

 

 Laurie

 Sydney  

 ---  Kayberg(at)aol.com wrote:

 

 

 

 

 


	


 

Never Miss an Email

Stay connected with Yahoo! Mail on your mobile.  Get started!

http://mobile.yahoo.com/services?promote=mail

lozhoffman(at)yahoo.com
Guest

Posted: Mon Jan 22, 2007 7:44 pm Post subject: Thoughts on Upgrades

Doug,

just in case you aren't already aware of it, shock

cooling is a major source of premature cylinder head

failure. Its something to be very mindful of if

shutting down midflight.



We fitted a LCD shock cooling alert to the Super cub

that I flew towing gliders for many years and it was

invaluable. We also had one fitted to another

motorglider which had cowl flaps just in case adequate

checks weren't carried out.



Its not so much the absolute temp changes but the rate

of cooling which is critical. Initial power reductions

should be very minor and incremental. We gradually

pull power back over several minutes until the CHT is

quite low before shutting down. Something to keep in

mind with the Lightning.



Sure is nice to be able to shutdown and glide those

last 50 miles from a good cruising level even when no

lift is available!

Laurie



--- Kayberg(at)aol.com wrote:



 	  Quote: 	
		    

 Laurie,

  

 I know you have already responded to Buz and agree

 at least in principle  

 with both of us, but I want to just note that the

 Limbach is a fine motor, but  

 different in design....as well as only 2/3 the

 horsepower of the 3300  Jabiru.  

  Not to mention it is bolted to a motorglider.  I 

 suspect the weights of 

 both aircraft are similar, as well as the engines.  

 In fact, the Limbach may be 

 slightly heavier.

  

 Without that prop, you really cannot motorglide, of

 course.  Or at  least not 

 nearly as well.

  

 Ryan has been amusing himself lately by shutting the

 Jabiru engine down and  

 gliding from significant distances away from the

 field to see how well he can  

 glide/practice engine-outs.  It really is quite

 substantial.    The suggested 

 17:1 glide ratio is not far off.  I suspect you are

 closer to  25:1   Our 

 skills dont include soaring just yet, even tho we

 are near  a good ridge to 

 practice on. 

  

 But It really is about the horsepower.

  

 Doug Koenigberg

  

  

 In a message dated 1/22/2007 8:01:05 PM Eastern

 Standard Time,  

 lozhoffman(at)yahoo.com writes:

 

 

 Doug,

 Re pitch change allowing faster cruise  speeds....

 

 We have a Hoffmann 3 position variable pitch prop on

 our  80hp Dimona motorglider. Fine for takeoff,

 course

 for cruise and feather  for gliding engine off. The

 prop is ground adjustable for pitch variations  in

 any

 of these settings.

 

 In fine, the Limbach engine provides a  rate of

 climb

 of around 400'-450'fpm (at) 55kts. It would rapidly

 approach  and exceed red line of 3200rpm

 (3000-3200rpm

 continuous for <5mins  permitted on takeoff) beyond

 60kts IAS even in climb. 

 

 Resetting the  pitch to cruise provides an IAS of

 85-90kts (at) 2700rpm. In our case at least  the pitch

 variation does make a big difference to cruise speed

 achieved.  

 

 As an aside, I am amazed at just how small a

 variation

 in pitch  there is between our fine and course

 settings. Observing the pitch change  from outside

 the

 cockpit while someone in it alters the settings, 

 the

 change is barely discernable.

 

 Laurie

 Sydney  

 ---  Kayberg(at)aol.com wrote:

 

 

 

 

 


	


 

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dashvii(at)hotmail.com
Guest

Posted: Mon Jan 22, 2007 8:24 pm Post subject: Thoughts on Upgrades

One of the things that I am going to try to do is to determine the 

coefficient of drag on the Lightning before and after my modifications.  

 	  Quote: 	
		  From that I can give you a better guess at how much performance gains I can 

get out of the speed mods.  I'll also do the glide testing to verify data.  
	


I'll have use of an instrumentation package to record the inflight data and 

can download that into the laptop when I get down.  Should be interesting.  

Brian W.



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Scotty

Joined: 08 Oct 2006
Posts: 44
Location: Peachtree City, GA

Posted: Tue Jan 23, 2007 6:09 am Post subject: Re: Thoughts on Upgrades

Wouldn't an Angle of Attack indicator tell you the best glide speed, or do I understand the things all wrong?

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