X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-qy0-f200.google.com ([209.85.221.200] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with ESMTP id 4119883 for flyrotary@lancaironline.net; Wed, 10 Feb 2010 15:51:47 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.221.200; envelope-from=rwstracy@gmail.com Received: by qyk38 with SMTP id 38so375772qyk.1 for ; Wed, 10 Feb 2010 12:51:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:message-id:subject:from:to :content-type; bh=MWa3Le35GIdAX3ED8VSv4uXpmGIiJyR9MkX0Pelz1VY=; b=XTYV/EOZKQanEAGk+tqre8TCCkYeGlqY4mQhoop3/4WbslpNc9obL9Oj4FRuivTsNS xinkedudjml4n63xfl9Xocg3gkRgLDJ9nGWX/Uf8+Z09s2F9j0P7MUJRs5QEEuKfSyQA 28ytd3VxRwjW7gFj5Rr+j3dAxCPCsffIoVclc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; b=eR1l7pXeChtTBRY2ndxTmWT1JkupxjMbtMambE1Ow41PqSpUKvQH4jwqUqnvZ4wqT2 Weqqv/0xCCRvYZREzKYgW3Uvy+t7KllijPdcp+0EP6qpZUjI/kEaRrIVeei0X4XvL5Q1 uiCQYzfaRCWUKDumSZCLeujENhJzGba9FupDQ= MIME-Version: 1.0 Sender: rwstracy@gmail.com Received: by 10.224.63.133 with SMTP id b5mr449747qai.350.1265835072288; Wed, 10 Feb 2010 12:51:12 -0800 (PST) In-Reply-To: References: Date: Wed, 10 Feb 2010 15:51:12 -0500 X-Google-Sender-Auth: 5184197f22acf69c Message-ID: <1b4b137c1002101251w21b1ec99tff498ee88f9d1902@mail.gmail.com> Subject: Re: [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: N.A. Renesis to turbo From: Tracy Crook To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=00c09f99e122d3f8df047f453151 --00c09f99e122d3f8df047f453151 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable I won a pretty good bet on that logic once. The flaw is that an airfoil (= a prop is an airfoil) generates lift (or thrust in this case) at zero angle o= f attack due to mr Bernoulli's stuff. Trying to calculate airspeed based on those pitch numbers is a waste of time if all you have is that numerical pitch number which is usually based on the angle at the flat side of the airfoil. But then again, no 2 prop makers define it the same way. Tracy On Wed, Feb 10, 2010 at 3:27 PM, Jeff Whaley wrote: > Hey Tracy, you=92re doing better than theoretical =85 > > 6300 engine rpm / 2.17 =3D 2903.225 prop rpm > > 2903.225 prop rpm x 60 =3D 174193.548 prop rph (revs per hour) > > 174193.548 rph x 71 inch pitch =3D 12367741.935 inches of forward travel = per > hour > > 12367741.935=94 / 12 =3D 1030645.131 feet per hour > > 1030645.161 fph / 5280 =3D 195.2 mph > > Your 209 mph appears to be better than best theoretical =85 > > 209 / 195.2 =3D 1.07; > > 1.07 x 2903.225 =3D 3108 prop rpm / or 1.07 x 71 =3D 75.97 inch pitch = =85 the > following table from Warp Drive gives same numbers. > > 210 mph at 2900 rpm requires 76=94 pitch; or conversely 210 mph at 71=94 = pitch > requires 3100 rpm. > > Jeff > > > > > > *Prop RPM* > > *Cruise Air Speed* > > *2600* > > *2700* > > *2800* > > *2900* > > *3000* > > *3100* > > *3200* > > *3300* > > *3400* > > *3500* > > *3600* > > *3700* > > *3800* > > *3900* > > *4000* > > *4100* > > *4200* > > *220* > > 89 > > 86 > > 83 > > 80 > > 77 > > 75 > > 73 > > 70 > > 68 > > 66 > > 65 > > 63 > > 61 > > 60 > > 58 > > 56 > > 55 > > *210* > > 85 > > 82 > > 79 > > 76 > > 74 > > 71 > > 69 > > 67 > > 65 > > 63 > > 62 > > 60 > > 58 > > 57 > > 55 > > 54 > > 53 > > *200* > > 81 > > 78 > > 75 > > 72 > > 70 > > 68 > > 66 > > 65 > > 62 > > 61 > > 59 > > 57 > > 56 > > 54 > > 53 > > 51 > > 50 > > *190* > > 77 > > 74 > > 72 > > 69 > > 67 > > 65 > > 63 > > 61 > > 59 > > 57 > > 56 > > 54 > > 53 > > 51 > > 50 > > 49 > > 48 > > *180* > > 73 > > 70 > > 68 > > 66 > > 63 > > 61 > > 59 > > 58 > > 56 > > 54 > > 53 > > 52 > > 50 > > 49 > > 48 > > 46 > > 45 > > > > > > *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] *O= n > Behalf Of *Tracy Crook > *Sent:* Wednesday, February 10, 2010 8:35 AM > *To:* Rotary motors in aircraft > *Subject:* [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: N.A= . > Renesis to turbo > > > > Sun 100 flown at 500 ft. > Top speed on a normally aspirated aircraft is always best at sealevel. > Best fuel economy is reached up high. > > Tracy > > On Tue, Feb 9, 2010 at 10:45 PM, Mike Wills wrote: > > When you guys put out these numbers (RPM, speed, etc...) would also be > helpful to know at what altitude. I assume at or close to sea level? I > havent yet made any speed runs at low altitude. > > > > Mike > > > > *From:* Tracy Crook > > *Sent:* Tuesday, February 09, 2010 5:27 PM > > *To:* Rotary motors in aircraft > > *Subject:* [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: N.A= . > Renesis to turbo > > > > Tracy, if you have the data could you give us the RPMs you saw at the 20= 5 > and 217.5 air speeds? > > Dennis H. > Renesis RV-7A > Austin, Tx. > > That was 209 and 217.5 > > the 209 mph speed was with the 2.176 drive turning a 68 - 71 prop with > engine turning 6300 , mixture leaned to 17 gph. On other occasions I cou= ld > push it to 6400 at best power mixture burning 20 gph. > > The 217.5 mph was with a 2.85 drive turning a 74 - 88 prop with engine > turning 7250. I didn't get a good read on the fuel flow but obviously it > would have been higher. I remember requesting priority landing after the > race due to low fuel. > > Neither run was done at best power mixture but leaned a few gph less than > max. > > Tracy > > > > This message, and the documents attached hereto, is intended only for the > addressee and may contain privileged or confidential information. Any > unauthorized disclosure is strictly prohibited. If you have received this > message in error, please notify us immediately so that we may correct our > internal records. Please then delete the original message. Thank you. > --00c09f99e122d3f8df047f453151 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable I won a pretty good bet on that logic once.=A0=A0 The flaw is that an airfo= il (a prop is an airfoil) generates lift (or thrust in this case) at zero a= ngle of attack due to mr Bernoulli's stuff.=A0 Trying to calculate airs= peed based on those pitch numbers is a waste of time if all you have is tha= t numerical pitch number which is usually based on the angle at the flat si= de of the airfoil.=A0=A0 But then again, no 2 prop makers define it the sam= e way.

Tracy

On Wed, Feb 10, 2010 at 3:27 PM= , Jeff Whaley <jwhaley@datacast.com> wrote:

Hey Tracy, you=92re doing better than theoretical =85

6300 engine rpm / 2.17 =3D 2903.225 prop rpm

2903.225 prop rpm x 60 =3D 174193.548 prop rph (revs per hour)=

174193.548 rph x 71 inch pitch =3D 12367741.935 inches of forward tra= vel per hour

12367741.935=94 / 12 =3D 1030645.131 feet per hour

1030645.161 fph / 5280 =3D 195.2 mph

Your 209 mph appears to be better than best theoretical =A0=85

209 / 195.2 =3D 1.07;

1.07 x 2903.225 =3D 3108 prop rpm =A0/ or 1.07 x 71 =3D 75.97 inch pi= tch =85 the following table from Warp Drive gives same numbers.

210 mph at 2900 rpm requires 76=94 pitch; or conversely 210 mph at 71= =94 pitch requires 3100 rpm.

Jeff

=A0

=A0

Prop RPM

Cr= uise Air Speed

26= 00

27= 00

28= 00

29= 00

30= 00

31= 00

32= 00

33= 00

34= 00

35= 00

36= 00

37= 00

38= 00

39= 00

40= 00

41= 00

42= 00

22= 0

89

86

83

80

77

75

73

70

68

66

65

63

61

60

58

56

55

21= 0

85

82

79

76

74

71

69

67

65

63

62

60

58

57

55

54

53

20= 0

81

78

75

72

70

68

66

65

62

61

59

57

56

54

53

51

50

19= 0

77

74

72

69

67

65

63

61

59

57

56

54

53

51

50

49

48

18= 0

73

70

68

66

63

61

59

58

56

54

53

52

50

49

48

46

45

=A0

=A0

From:= Rotary motors in aircraft [mailto:flyrotary@lancair= online.net] On Behalf Of Tracy Crook
Sent: Wednesday, February 10, 2010 8:35 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: = N.A. Renesis to turbo

=A0

Sun 100 flown at 500 = ft.
Top speed on a normally aspirated aircraft is always best at sealevel.=A0= =A0 Best fuel economy is reached up high.

Tracy

On Tue, Feb 9, 2010 at 10:45 PM, Mike Wills <rv-4mike@cox.net> = wrote:

When you guys put out these numbers (RPM, spee= d, etc...) would also be helpful to know at what altitude. I assume at or c= lose to sea level? I havent yet made any speed runs at low altitude.=

=A0

Mike

=A0

F= rom: Tracy Crook

S= ent: Tuesday, February 09, 2010= 5:27 PM

S= ubject: [FlyRotary] Re: rpm vs = Power was : Throttle limits was Re: N.A. Renesis to turbo

=A0

Tracy, if you have the= data could you give us the=A0 RPMs you saw at the 205 and 217.5 air speeds= ?

Dennis H.
Renesis RV-7A
Austin, Tx.

That was 209 and 217.5=A0=A0=A0

the 209 mph speed was with the 2.176 drive turning a 68 - 71 prop with engi= ne turning 6300 , mixture leaned to 17 gph.=A0 On other occasions I could p= ush it to 6400 at best power mixture burning 20 gph.

The 217.5 mph was with a 2.85 drive turning a 74 - 88 prop with engine turn= ing 7250.=A0 I didn't get a good read on the fuel flow but obviously it= would have been higher.=A0 I remember requesting priority landing after th= e race due to low fuel.=A0=A0

Neither run was done at best power mixture but leaned a few gph less than m= ax.

Tracy

=A0


This message, and the docum= ents attached hereto, is intended only for the addressee and may contain pr= ivileged or confidential information. Any unauthorized disclosure is strict= ly prohibited. If you have received this message in error, please notify us immediately so that we may correct our = internal records. Please then delete the original message. Thank you.

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