Matronics Email Lists :: View topic - Initial biuld decisions

Matronics Email Lists
Web Forum Interface to the Matronics Email Lists

Get Email Distribution Too! FAQ Search Memberlist Usergroups Register

Profile Log in to check your private messages Log in

Initial biuld decisions

Matronics Email Lists Forum Index -> RV7-List

View previous topic :: View next topic

Author Message

rafael(at)gforcecable.com
Guest

Posted: Sat May 12, 2007 12:11 pm Post subject: Initial biuld decisions

First of all, I thank all who provided me with input in making the decision between a 9A and 7A.  I have decided to build the 7A.  It has not been an easy decision.  Basically the balance tilted towards the 7 after considering the Vne and the added performance with the 360 engine.  

   

Now I would like help with a couple of other decisions.  First, IO-360 vs O-360.  I was leaning heavily towards the injected engine, carburetor heat being the issue.  However, after attending an EAA meeting this morning and talking to an RV-8 builder with a beautiful 8A with an O-360, I’m no longer sure.  What advantages does the fuel injection have?  Performance?  Reliability?  Ease of installation?  Maintenance?  Any other? I believe cost and weight penalty are close for either engine.   

   

The other decision is between Constant Speed and Fixed Pitch prop.  It is my understanding that the CS will provided better takeoff and climb figures and marginally better cruise performance.  I’m wondering if this performance is worth the extra $6500 or so for the CS.  I’m leaning towards the FP implementation, but I would like to hear comments.  

   

Thanks and best regards to all,  

   

Rafael  

       [quote][b]

frank.hinde(at)hp.com
Guest

Posted: Sat May 12, 2007 12:32 pm Post subject: Initial biuld decisions

FI is more efficient and shows up most when running lean of  peak (LOP). this can be a saving in the order of 1.5GPH at cruise.  Carb  heat is the big one, not really required on the FI but Vans does have a  rudimentry warm air system...Just in case.

  

 FP vs CS...depends on if the extra 300FPM its worth it to  ya....Resale value is higher of course with a CS...and there is the "cool"  factor..... I belive stopping distances are improved with the CS as  well.

  

 Frank



   From: owner-rv7-list-server(at)matronics.com  [mailto:owner-rv7-list-server(at)matronics.com] On Behalf Of  Rafael

Sent: Saturday, May 12, 2007 1:11 PM

To:  rv9-list(at)matronics.com; rv7-list(at)matronics.com

Subject: RV7-List:  Initial biuld decisions

 

  

First of all, I thank all who  provided me with input in making the decision between a 9A and 7A.  I have  decided to build the 7A.  It has not been an easy decision.  Basically  the balance tilted towards the 7 after considering the Vne and the added  performance with the 360 engine. 

  

Now I would like help with a couple  of other decisions.  First, IO-360 vs O-360.  I was leaning heavily  towards the injected engine, carburetor heat being the issue.  However,  after attending an EAA meeting this morning and talking to an RV-8 builder with  a beautiful 8A with an O-360, I’m no longer sure.  What advantages does the  fuel injection have?  Performance?  Reliability?  Ease of  installation?  Maintenance?  Any other? I believe cost and weight  penalty are close for either engine.  

  

The other decision is between  Constant Speed and Fixed Pitch prop.  It is my understanding that the CS  will provided better takeoff and climb figures and marginally better cruise  performance.  I’m wondering if this performance is worth the extra $6500 or  so for the CS.  I’m leaning towards the FP implementation, but I would like  to hear comments. 

  

Thanks and best regards to  all, 

  

Rafael

[quote]



href="http://www.matronics.com/Navigator?RV7-List">http://www.matronics.com/Navigator?RV7-List

href="http://forums.matronics.com">http://forums.matronics.com



[b]

mtaylo17(at)msn.com
Guest

Posted: Sat May 12, 2007 2:13 pm Post subject: Initial biuld decisions

I went with a constant speed prop for my IOF-360. It's great for descents too as you don't have to worry about overspeeding your engine. Just push the nose forward and go for it! When you throttle back with a constant speed prop, it's like putting the brakes on which is also nice coming into the pattern at warp factor 7. Just before you enter, throttle back and you'll be at pattern speed before you know it. Mine's a three blade MT BTW. It's not as fast in cruise.

  

 Mark

 www.4sierratango.com

 



 

 [quote]  From: rafael(at)gforcecable.com

To: rv9-list(at)matronics.com; rv7-list(at)matronics.com

Subject: Initial biuld decisions

Date: Sat, 12 May 2007 16:10:32 -0400



   .ExternalClass EC_p.MsoNormal, .ExternalClass EC_li.MsoNormal, .ExternalClass EC_div.MsoNormal {margin-bottom:.0001pt;font-size:12.0pt;font-family:'Times New Roman';} .ExternalClass EC_a:link, .ExternalClass EC_span.MsoHyperlink {color:blue;text-decoration:underline;} .ExternalClass EC_a:visited, .ExternalClass EC_span.MsoHyperlinkFollowed {color:purple;text-decoration:underline;} .ExternalClass EC_span.EmailStyle17 {font-family:Arial;color:windowtext;} (at)page Section1 {size:8.5in 11.0in;} .ExternalClass EC_div.Section1 {page:Section1;}     

First of all, I thank all who provided me with input in making the decision between a 9A and 7A.  I have decided to build the 7A.  It has not been an easy decision.  Basically the balance tilted towards the 7 after considering the Vne and the added performance with the 360 engine. 

  

Now I would like help with a couple of other decisions.  First, IO-360 vs O-360.  I was leaning heavily towards the injected engine, carburetor heat being the issue.  However, after attending an EAA meeting this morning and talking to an RV-8 builder with a beautiful 8A with an O-360, I’m no longer sure.  What advantages does the fuel injection have?  Performance?  Reliability?  Ease of installation?  Maintenance?  Any other? I believe cost and weight penalty are close for either engine.  

  

The other decision is between Constant Speed and Fixed Pitch prop.  It is my understanding that the CS will provided better takeoff and climb figures and marginally better cruise performance.  I’m wondering if this performance is worth the extra $6500 or so for the CS.  I’m leaning towards the FP implementation, but I would like to hear comments. 

  

Thanks and best regards to all, 

  

Rafael

 	  Quote: 	
		  



et=_blank>http://www.matronics.com/Navigator?RV7-List

p://forums.matronics.com



	
[b]

fstringham

Joined: 10 Jan 2006
Posts: 87

Posted: Sat May 12, 2007 3:00 pm Post subject: Initial biuld decisions

Rafeal



When I started my project (Sept 2004) I wasn't sure what I wanted. But as 

the project unfolded I decided (very slowly) to turn a Van's 

quick/light/simple flyer into a mega buck high speed/leading edge 

technically/very costly RV7A......ECI Titan IO360/cold air 

induction/FI/EI/ALL GLASS-Electric Panel/WhirlWind 200RV CS prop/custom 

interior.................$$$$$$$$$$$$$$$$. I just coundn't 

resist...........Now if I build another RV It is going to be built 

simple/light weight/night VFR/less costly......

I know those that are flying can give better stats on the difference in the 

all important velocity factor between a simple and complex 

craft.....but....I believe one would get as much utiliy out of a less costly 

simple plane as compared to the 777 that some of us are trying to build.



Good Luck in your build/decided on your mission/and have fun!!!!



Frank (at) SGU  RV7A   'NDY"





 	  Quote: 	
		  From: "Rafael" <rafael(at)gforcecable.com>

Reply-To: rv7-list(at)matronics.com

To: <rv9-list(at)matronics.com>, <rv7-list(at)matronics.com>

Subject: Initial biuld decisions

Date: Sat, 12 May 2007 16:10:32 -0400



First of all, I thank all who provided me with input in making the decision

between a 9A and 7A.  I have decided to build the 7A.  It has not been an

easy decision.  Basically the balance tilted towards the 7 after 

considering

the Vne and the added performance with the 360 engine.



Now I would like help with a couple of other decisions.  First, IO-360 vs

O-360.  I was leaning heavily towards the injected engine, carburetor heat

being the issue.  However, after attending an EAA meeting this morning and

talking to an RV-8 builder with a beautiful 8A with an O-360, I'm no longer

sure.  What advantages does the fuel injection have?  Performance?

Reliability?  Ease of installation?  Maintenance?  Any other? I believe 

cost

and weight penalty are close for either engine.



The other decision is between Constant Speed and Fixed Pitch prop.  It is 

my

understanding that the CS will provided better takeoff and climb figures 

and

marginally better cruise performance.  I'm wondering if this performance is

worth the extra $6500 or so for the CS.  I'm leaning towards the FP

implementation, but I would like to hear comments.



Thanks and best regards to all,



Rafael




	


_________________________________________________________________

Catch suspicious messages before you open them—with Windows Live Hotmail.

matronics(at)cencula.com
Guest

Posted: Sun May 13, 2007 6:52 am Post subject: Initial biuld decisions

I've been wondering some of the same  things as Rafael, but would like to add 

one more question:



When selecting an engine, does the choice of fixed pitch vs CS have any 

bearing on choosing Dynafocal I vs. Dynafocal II?



I read a posting on this list that indicated Dynafocal II was intended for CS 

props.  The argument was that the center of mass is further forward on a CS 

installation, so the focus of the mounts is further forward to match that and 

reduce vibration.



Is this actually true?  I've been able to find no other info to back this up, 

although I have found quite a few people flying Dynafocal I motors with CS 

props (which would seem to contradict the posting).



The posting is here in case anyone wants to read it:



http://www.matronics.com/searching/getmsg_script.cgi?INDEX=5148244?KEYS=dynafocal_&_engine_&_code?LISTNAME=RV?HITNUMBER=8?SERIAL=07422721769?SHOWBUTTONS=YES



Thanks,



Mike Cencula

On Saturday May 12 2007 04:10 pm, Rafael wrote:

 	  Quote: 	
		   First of all, I thank all who provided me with input in making the decision

 between a 9A and 7A.  I have decided to build the 7A.  It has not been an

 easy decision.  Basically the balance tilted towards the 7 after

 considering the Vne and the added performance with the 360 engine.



 Now I would like help with a couple of other decisions.  First, IO-360 vs

 O-360.  I was leaning heavily towards the injected engine, carburetor heat

 being the issue.  However, after attending an EAA meeting this morning and

 talking to an RV-8 builder with a beautiful 8A with an O-360, I'm no longer

 sure.  What advantages does the fuel injection have?  Performance?

 Reliability?  Ease of installation?  Maintenance?  Any other? I believe

 cost and weight penalty are close for either engine.



 The other decision is between Constant Speed and Fixed Pitch prop.  It is

 my understanding that the CS will provided better takeoff and climb figures

 and marginally better cruise performance.  I'm wondering if this

 performance is worth the extra $6500 or so for the CS.  I'm leaning towards

 the FP implementation, but I would like to hear comments.



 Thanks and best regards to all,



 Rafael

sportypilot(at)stx.rr.com
Guest

Posted: Sun May 13, 2007 8:14 am Post subject: Initial biuld decisions

Dynafocal I is the standard engine case type where the engine connects

      To the engine mount, conical is the older style engine cases and they 

      Can be converted to dynafocal I  for about 400.00 at places like ECI,



      Dynafocal II was an oddball engine type done on a few factory type 

      Aircraft, these choices have nothing to do with CS or fixed pitch 

      Crankshafts, those differences are only if the crankshaft has a 

      Hollow end on the crankshaft.. Vans sells all three mounts,but they

      Will Make you sign a not return form for the conical or Dynafocal II 

      Engine mounts.. I would stick with the dynafocal I mount and you still



      Can buy an engine that has the hollow crankshaft and use a fixed pitch



      Prop (it takes plugs in the end of the crank) and later you can move

      Up to constant speed prop when you can afford it.. having options is

      A good thing.. these items are in the preview plans.. if you have them

          Danny.. 




I've been wondering some of the same  things as Rafael, but would like to

add 

one more question:



When selecting an engine, does the choice of fixed pitch vs CS have any 

bearing on choosing Dynafocal I vs. Dynafocal II?



I read a posting on this list that indicated Dynafocal II was intended for

CS 

props.  The argument was that the center of mass is further forward on a CS 

installation, so the focus of the mounts is further forward to match that

and 

reduce vibration.



Is this actually true?  I've been able to find no other info to back this

up, 

although I have found quite a few people flying Dynafocal I motors with CS 

props (which would seem to contradict the posting).



The posting is here in case anyone wants to read it:



http://www.matronics.com/searching/getmsg_script.cgi?INDEX=5148244?KEYS=dyna

focal_&_engine_&_code?LISTNAME=RV?HITNUMBER=8?SERIAL=07422721769?SHOWBUTTONS

=YES



Thanks,



Mike Cencula

On Saturday May 12 2007 04:10 pm, Rafael wrote:

 	  Quote: 	
		   First of all, I thank all who provided me with input in making the

decision
	


 	  Quote: 	
		   between a 9A and 7A.  I have decided to build the 7A.  It has not been an

 easy decision.  Basically the balance tilted towards the 7 after

 considering the Vne and the added performance with the 360 engine.



 Now I would like help with a couple of other decisions.  First, IO-360 vs

 O-360.  I was leaning heavily towards the injected engine, carburetor heat

 being the issue.  However, after attending an EAA meeting this morning and

 talking to an RV-8 builder with a beautiful 8A with an O-360, I'm no

longer
	


 	  Quote: 	
		   sure.  What advantages does the fuel injection have?  Performance?

 Reliability?  Ease of installation?  Maintenance?  Any other? I believe

 cost and weight penalty are close for either engine.



 The other decision is between Constant Speed and Fixed Pitch prop.  It is

 my understanding that the CS will provided better takeoff and climb

figures
	


 	  Quote: 	
		   and marginally better cruise performance.  I'm wondering if this

 performance is worth the extra $6500 or so for the CS.  I'm leaning

towards
	


 	  Quote: 	
		   the FP implementation, but I would like to hear comments.



 Thanks and best regards to all,



 Rafael

cnpeters

Joined: 24 Aug 2006
Posts: 23
Location: Bloomington/Normal, IL

Posted: Sun May 13, 2007 8:04 pm Post subject: Initial biuld decisions

I posted this on the RV-9 list as you posted your query there, too.

Rafael,

A couple things:

1) Regarding Vne and the O-360, it shouldn't be a big deal with the 

RV-9. There are quite a few O-360 powered -9's out there, and you won't 

flirt with Vne in cruise. The only time it would be an issue is in a 

dive/descent, a small part of your time flying. One will need to watch 

for Vne with both the O-360 or O-320 in a descent - the former will make 

it a bit easier to get close in a more shallow descent. Just throttle 

back, that's it. The attention to this is no different than other 

critical areas of flight, such as the landing.

2) Between the O- and IO-360, there are many threads on this in the 

archives for the various forums. Weight will be a non issue. The 

injected models main advantage IMHO is to run lean of peak and achieve 1 

gph improvement in fuel burn. A more balanced fuel mixture to each 

cylinder is possible. You don't have to worry about carb icing. But, 

there is some complexity, higher fuel line pressures, need for a return 

fuel line to a tank and more expensive fuel selector, more difficult hot 

starts. There are others on these forums that have much more real world 

info since I'm still a builder.

3) FP vs CS prop - this is one of the the top three debates that rage 

amongst the OBAM market (along with to prime or not, slider vs tip-up, 

etc). I'm still deciding on that one, and have a year still to worry. 

Frankly, I'm leaning toward an FP - lighter weight, MUCH cheaper, less 

maintenance/overhaul issues. Craig Catto builds a beautiful 3 blade prop 

that I have flown behind in a -9 - smooth, excellent craftmanship, and 

costs $1800. He (and other manufacturers) can set you up with a prop 

that is coarse pitched that will give you Van's cruise numbers. 

Comparing performance numbers from various builders shows cruise numbers 

about equal between a properly configured cruise FP vs a CS. You will 

sacrifice climb rate/takeoff distance a bit, so if you fly into hot and 

high or short fields all the time, then you need to re-think this. But 

honestly, I do all my flying in Illinois and elsewhere into airports 

with at least 3500' strips - really look at Van's T/O and landing 

numbers with a FP prop in the -9. There are few places where you can't 

go that a CS will make a difference. On the flip side a CS resell may be 

better, especially with the -7. Acro and formation flying have some 

benefit with a CS. One thing against the FP is slowing down and descent 

rate. Coming into the pattern and trying to slow down takes a little 

more forethought and earlier energy management with the FP, since the CS 

can give a little drag when in fine pitch and help out. This is 

particularly so with the -9. Basically, I think the argument is a little 

silly, as some practice will make you competent. I fly a Dakota with a 

CS, but have no trouble when I grab the glider-like Diamond DA-20 with 

FP after practicing with it a little once or twice.  So, for me, I'll 

likely go with the FP and use the $5000 saved over the CS for about 1500 

gal of avgas. That's quite a few cross-country trips!

Carl

_________________
Carl Peters
RV-9A wings

John Brunke

Joined: 10 Jan 2006
Posts: 43

Posted: Mon May 14, 2007 5:56 am Post subject: Initial biuld decisions

Dear Carl,



In your well written response you wrote:

 	  Quote: 	
		   there is some complexity, higher fuel line pressures, need for a return 

 fuel line to a tank and more expensive fuel selector, more difficult hot 

 starts.


	


In my search for engines that started at Sun and Fun, I specifically asked 

the fuel

return question to most of the engine sales people.   Aerosport and 

Mattituck both

said a return line is not needed in their fuel injection systems.   I can't 

remember

the response of the other engine groups, but reducing complexity is probably

better for sales.



I always assumed one would be required also.   That eliminates some of the 

complexity issue and relief for

me since I had already sealed up my tanks.



That also means a less expensive fuel selector, so that might bring the 

injection

system somewhat closer in price to the carb system.



As for the hot start issue that could be a problem.   Lycoming is now 

selling non certified engines and

Jon ( the project manager, sorry I can't remember his last name),  showed me 

a return loop that ties into

the fuel line between the tank and the electric fuel pump.   You run that 

for a few seconds and it cycles

colder fuel foward of the firewall.   That should solve the hot start issue. 

That adds complexity and

on the fuel injected airplane I owned at one time, I would just open the oil 

filler door after landing and

that seemed to work well to cool things down.



During one quick fuel stop we landed, pulled up to the pumps, the FBO filled

her up, we paid, and got right out of there.  It started right up and it had 

been shut down for no more

than 15 minutes.    And that was in the middle of summer.  OAT around 85 F.



Sincerely,

John Brunke

frank.hinde(at)hp.com
Guest

Posted: Mon May 14, 2007 8:01 am Post subject: Initial biuld decisions

You could easily add an Airflow Performance "dump valve" to just about

any FI system. This simply needs a return to either tank.



It is only used to purge the hot fuel from firewall forward doing a hot

start. It works, adds very little complexity and does not require any

change to the standard selector valve.



Frank 



--

cnpeters

Joined: 24 Aug 2006
Posts: 23
Location: Bloomington/Normal, IL

Posted: Tue May 15, 2007 7:03 pm Post subject: Initial biuld decisions

Good to know on the fuel return issue not being mandatory with some 

makers - thanks for the correction. And no expensive Andair valve. There 

was a thread in VAF about FI hot starts and all the tips from flyers did 

point to being not too great an issue even without a dump or return 

line. To blur things further, there are those with carb engines that do 

run LOP - Pete Howell just posted on the RV-9-list about doing this with 

an engine monitor.

_________________
Carl Peters
RV-9A wings

ceengland(at)bellsouth.ne
Guest

Posted: Thu May 17, 2007 5:45 pm Post subject: Initial biuld decisions

Michael D. Cencula wrote:

 	  Quote: 	
		   

 

 I've been wondering some of the same  things as Rafael, but would like to add 

 one more question:

 

 When selecting an engine, does the choice of fixed pitch vs CS have any 

 bearing on choosing Dynafocal I vs. Dynafocal II?

 

 I read a posting on this list that indicated Dynafocal II was intended for CS 

 props.  The argument was that the center of mass is further forward on a CS 

 installation, so the focus of the mounts is further forward to match that and 

 reduce vibration.

 

 Is this actually true?  I've been able to find no other info to back this up, 

 although I have found quite a few people flying Dynafocal I motors with CS 

 props (which would seem to contradict the posting).

 

 The posting is here in case anyone wants to read it:

 

 http://www.matronics.com/searching/getmsg_script.cgi?INDEX=5148244?KEYS=dynafocal_&_engine_&_code?LISTNAME=RV?HITNUMBER=8?SERIAL=07422721769?SHOWBUTTONS=YES

 

 Thanks,

 

 Mike Cencula

 

snipped
	




Dyna II was created for certain twins using extended hub props. I called 

Van's tech help a couple of months ago, trying to determine if I could 

order my finish kit without a specific engine selected. One thing they 

told me was that the type II mount is no longer available due to 

non-existent demand. You might want to verify that directly with Van's.



Charlie

(anybody with a mid-time x-360x they want to part with?)

Display posts from previous:

	Matronics Email Lists Forum Index -> RV7-List	All times are GMT - 8 Hours
Page 1 of 1

Jump to:

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You cannot attach files in this forum
You can download files in this forum