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Setting prop to revs

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Graeme Toft

Joined: 09 Jan 2006
Posts: 123

Posted: Sun Jul 23, 2006 7:02 pm Post subject: Setting prop to revs

Hi guys, I have my prop bolted on and will  be experimenting with pitch soon but as I am unsure what my max  static revs should be I am a bit concerned. Can some body with an NSI non turbo  and ground adjustable prop tell me what revs I should expect to see for  best results. I was getting 4700 rpm flat out but feel I should be seeing over  5500 rpm. The prop I have put on is a 72 inch 3 blade composite which when  installed into the hub comes down to 70inch.  

  

 Regards

Graeme  Toft

janderson412(at)hotmail.c
Guest

Posted: Sun Jul 23, 2006 8:13 pm Post subject: Setting prop to revs

Fo a start Graeme, if you get 5000 static, that will certinly get you flying safely. At 4700 your'e very near top of the  tq curve. John A.



  	  Quote: 	
		        Hi guys, I have my prop bolted on and will be experimenting with pitch soon but as I am unsure what my max static revs should be I am a bit concerned. Can some body with an NSI non turbo and ground adjustable prop tell me what revs I should expect to see for best results. I was getting 4700 rpm flat out but feel I should be seeing over 5500 rpm. The prop I have put on is a 72 inch 3 blade composite which when installed into the hub comes down to 70inch.  

  

 Regards

Graeme Toft

	


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Graeme Toft

Joined: 09 Jan 2006
Posts: 123

Posted: Sun Jul 23, 2006 10:09 pm Post subject: Setting prop to revs

Hi John, thanks for the advice. I've been following  the threads going back and forth between yourself and others with your own plane  and being at the same point myself with engine info requirements Im really close  to flying. The problem I have is that I was sent an NSI data sheet on engine  performance and in it the advice was that take off engine revs should  be around 6200. I shook my head in disbelieve at these figures and asked a mate  who overhauled my engine what he thought and he agreed that the figures were  high. I was wondering if the figures quoted are for the NSI engine with the CAP  system. I dont know if that would make any difference or not but 6200 seem very  high and more a kin to the 2 stroke rev range than a four stroke.  Figures quoted in the NSI EA 81 OPERATING LIMITS are as  follows.

     

 Idle  RPM  1350-1400

 Cruise  RPM  3200-4500

 Take off RPM    6200

 Max Continuous RPM     5800

 Never exceed RPM     6500 

  

 Regards

Graeme 

 [quote]   ---

janderson412(at)hotmail.c
Guest

Posted: Mon Jul 24, 2006 1:19 am Post subject: Setting prop to revs

Yes, they certainly seem high to me me Graeme....I have a friend with a normally asperated EA81 and limits 5500 max for t/o. Goes very well, he has upped the comp ratio a little and bigger carb. You can always set the prop to give you more RPM for that one-of if your underpowered a bit but will cost on cruise. But that little engine sure is going to last longer at lower RPM. Is it a std EA81 or have you tweeked it a little? I limit to 5000 for t/o but rearly need it and 4000 for cruise but then I'm turbo'd. John



 [quote]   Hi John, thanks for the advice. I've been following the threads going back and forth between yourself and others with your own plane and being at the same point myself with engine info requirements Im really close to flying. The problem I have is that I was sent an NSI data sheet on engine performance and in it the advice was that take off engine revs should be around 6200. I shook my head in disbelieve at these figures and asked a mate who overhauled my engine what he thought and he agreed that the figures were high. I was wondering if the figures quoted are for the NSI engine with the CAP system. I dont know if that would make any difference or not but 6200 seem very high and more a kin to the 2 stroke rev range than a four stroke. Figures quoted in the NSI EA 81 OPERATING LIMITS are as follows.

     

 Idle  RPM  1350-1400

 Cruise  RPM  3200-4500

 Take off RPM    6200

 Max Continuous RPM    5800

 Never exceed RPM    6500 

  

 Regards

Graeme 

 [quote] ---

Graeme Toft

Joined: 09 Jan 2006
Posts: 123

Posted: Mon Jul 24, 2006 2:02 am Post subject: Setting prop to revs

John, its the NSI 108 HP model. I think they are  tweeked up a bit because the standard EA 81 is much lower in HP than that. Im  going to go with your figures when Im back in Yeppoon and see how it goes.  I'll let you know the results.

  

 Cheers

Graeme ----- Original Message  ----- 

 [quote]   From:    John    Anderson (janderson412(at)hotmail.com) 

   To: kitfox-list(at)matronics.com (kitfox-list(at)matronics.com) 

   Sent: Monday, July 24, 2006 7:15 PM

   Subject: Re: Setting prop to    revs

   



--> Kitfox-List message posted by: "John Anderson"          

Yes, they certainly seem high to me me Graeme....I have a friend with a    normally asperated EA81 and limits 5500 max for t/o. Goes very well, he has    upped the comp ratio a little and bigger carb. You can always set the prop to    give you more RPM for that one-of if your underpowered a bit but will    cost on cruise. But that little engine sure is going to last longer at lower    RPM. Is it a std EA81 or have you tweeked it a little? I limit to 5000    for t/o but rearly need it and 4000 for cruise but then I'm turbo'd.    John



   [quote]                Hi John, thanks for the advice. I've been      following the threads going back and forth between yourself and others with      your own plane and being at the same point myself with engine info      requirements Im really close to flying. The problem I have is that I was      sent an NSI data sheet on engine performance and in it the advice was      that take off engine revs should be around 6200. I shook my head      in disbelieve at these figures and asked a mate who overhauled my engine      what he thought and he agreed that the figures were high. I was wondering if      the figures quoted are for the NSI engine with the CAP system. I dont know      if that would make any difference or not but 6200 seem very high      and more a kin to the 2 stroke rev range than a four stroke.      Figures quoted in the NSI EA 81 OPERATING LIMITS are as      follows.

         

     Idle  RPM   1350-1400

     Cruise  RPM       3200-4500

     Take off RPM     6200

     Max Continuous RPM         5800

     Never exceed RPM         6500 

      

     Regards

Graeme 

     [quote]       ---

Float Flyr

Joined: 19 Jul 2006
Posts: 2704
Location: Campbellton, Newfoundland

Posted: Mon Jul 24, 2006 4:37 am Post subject: Setting prop to revs

they are high....  for a  car.  My subie red lines around 6200.  I haven't had it much over  5000.  I guess that's why airplane engines age in hours instead of hundreds  of thousands of miles.

  

 It sounds like they are saying  up to 6200 maximum for lift off, 5800 max for climb out and cruise around  4000.

  

 I would probably use 6000,  5500 and 4200 respectively.

  

 Just a  guess.

  

  

 

Noel [quote]   

   --

_________________
Noel Loveys
Kitfox III-A
Aerocet 1100 Floats

AMuller589(at)aol.com
Guest

Posted: Mon Jul 24, 2006 9:49 am Post subject: Setting prop to revs

These are the 2.2 liter 1999 engine limits  recommended by  EGGENFELLNER AIRCRAFT. As I recall the engine controller limits it to 6200  rpm      

 Engine  speed (EIS)  

 Maximum 5600  rpm

Climb  5200 rpm

Cruise  4500 â€“ 4800  rpm

Descent  (sufficient to avoid gearbox rattle)



 We were unable to get a good climb/cruise with the ground adjustable pitch  set for 5200 rpm at takeoff and settled on 4700rpm. That gives about 145mph IAS  but only 400 fpm rate of climb. Takeoff is about 380 ft however so it a;pears we  are getting good enough takeoff horsepower. Eggenfellner said for the type prop  we used 4700 was good for the takeoff rpm. He only recommends inflight  adjustable props and his turbocharged engines are run at full throttle 4700rpm  in the Rans aircraft.

Graeme Toft

Joined: 09 Jan 2006
Posts: 123

Posted: Mon Jul 24, 2006 1:22 pm Post subject: Setting prop to revs

Thanks Noel and AMuller. 

  

 Regards

Graeme 

  

 Do not archive

 --

wingsdown(at)comcast.net
Guest

Posted: Mon Jul 24, 2006 2:19 pm Post subject: Setting prop to revs

I would like to mention just incase you will  be doing the initial test flights, some do, that as you lift off and the  airspeed picks up the prop will unload and will RPMS increase. Not a big deal  but should you go pass the 6200 rev limiter, if that is where you have it set,  the engine will begin to cut out. Just pull back a bit on the go stick, but if  you are not ready one might get spooked. Just thought I would mention  it.

  

 Rick

 [quote]   

   --

Graeme Toft

Joined: 09 Jan 2006
Posts: 123

Posted: Mon Jul 24, 2006 2:52 pm Post subject: Setting prop to revs

Thanks Rick, do you feel that if I set the static revs at 5500 it  would avoid passing the 6200 limit when the engine unloads.

  

 Regards

Graeme 

 ---

wingsdown(at)comcast.net
Guest

Posted: Mon Jul 24, 2006 3:09 pm Post subject: Setting prop to revs

Think I would try 5200 first. Allot will  depend on how you prefer to climb, steep or shallow.

  

 Rick

 [quote]   

   --

janderson412(at)hotmail.c
Guest

Posted: Mon Jul 24, 2006 3:29 pm Post subject: Setting prop to revs

The 2.2 is designed to handle the higher RPM due to o/h cam. EA81 at high rpm those push rods are getting a real hammering. ~j~



  	  Quote: 	
		     These are the 2.2 liter 1999 engine limits  recommended by EGGENFELLNER AIRCRAFT. As I recall the engine controller limits it to 6200 rpm      

 Engine  speed (EIS)  

 Maximum 5600 rpm

Climb  5200 rpm

Cruise  4500 â€“ 4800 rpm

Descent  (sufficient to avoid gearbox rattle)



 We were unable to get a good climb/cruise with the ground adjustable pitch set for 5200 rpm at takeoff and settled on 4700rpm. That gives about 145mph IAS but only 400 fpm rate of climb. Takeoff is about 380 ft however so it a;pears we are getting good enough takeoff horsepower. Eggenfellner said for the type prop we used 4700 was good for the takeoff rpm. He only recommends inflight adjustable props and his turbocharged engines are run at full throttle 4700rpm in the Rans aircraft.



	


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janderson412(at)hotmail.c
Guest

Posted: Mon Jul 24, 2006 3:32 pm Post subject: Setting prop to revs

Any advice like this is really good as on the first flight the heart is really pounding for the first few minutes and the brain can have trouble keeping up...if it's like mine...~j~



 [quote]   I would like to mention just incase you will be doing the initial test flights, some do, that as you lift off and the airspeed picks up the prop will unload and will RPMS increase. Not a big deal but should you go pass the 6200 rev limiter, if that is where you have it set, the engine will begin to cut out. Just pull back a bit on the go stick, but if you are not ready one might get spooked. Just thought I would mention it.

  

 Rick

 [quote] 

 --

janderson412(at)hotmail.c
Guest

Posted: Mon Jul 24, 2006 3:45 pm Post subject: Setting prop to revs

What do you think Rick, it is better to have the prop set slightly on the fine side, don't need to use full throttle for the first t/o if it gets off ok, but there if you need it. I was truely amazed on first flight how quickly it flew. ~j~



 [quote]      Think I would try 5200 first. Allot will depend on how you prefer to climb, steep or shallow.

  

 Rick

 [quote] 

 --

wingsdown(at)comcast.net
Guest

Posted: Mon Jul 24, 2006 4:00 pm Post subject: Setting prop to revs

I  think that is a personal decision based on ones own experience and experience  level. OK I will throw this out there. I would set it so you can reach pattern  altitude before the prop unloads enough to hit the rev limiter. However with the  fixed prop you also have to consider what the max cruise speed is you want to be  able to attain.  That seems to be the eternal compromise with a fixed  prop.  Your setting will fall in there some where. But for now altitude is  definitely your friend. 

  

 Rick

 [quote]   

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