Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.2.8) with ESMTP id 616913 for flyrotary@lancaironline.net; Fri, 21 Jan 2005 18:35:31 -0500 Received-SPF: none receiver=logan.com; client-ip=24.25.9.101; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-185-127.carolina.rr.com [24.74.185.127]) by ms-smtp-02-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j0LNYw4S012071 for ; Fri, 21 Jan 2005 18:34:59 -0500 (EST) Message-ID: <006501c50012$1ec5d4a0$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Fuel Injector Sizing Date: Fri, 21 Jan 2005 18:37:07 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0062_01C4FFE8.35BB4F20" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_0062_01C4FFE8.35BB4F20 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable George, my fuel pressure gauge reads between 40 and 43 psi depending on = whether I have one or both pumps on. I fly with 40 psi (one pump). My = pump (with no flow) will give a pressure of 80 psi, but a regulator = keeps it at 40-43 psi. I generally check my pumps for their no-flow = pressure and have noticed over the 6 years that the pressure of the main = pump has decreased from 80 psi to 60 psi - so getting near replacement = time. The spare pump still produces 80 psi - less wear as it is = normally only on for take off and landing. Ed A ----- Original Message -----=20 From: George Lendich=20 To: Rotary motors in aircraft=20 Sent: Friday, January 21, 2005 5:52 PM Subject: [FlyRotary] Re: Fuel Injector Sizing Ken and Ed Anderson. Your info and advice is well recieved and timely for me - I didn't = know what to use, now at least I can talk with some knowledge to = suppliers. One small question if I may - what is the fuel rail pressure = usually? Thanks again! George ( down under) Hi Jerry and George, The debate over the optimal injector size has been going on for = years. I personally plan to use 400cc/38 lb or 440cc/42 lb Ford = injectors. According to = http://www.maxcooper.com/rx7/how-to/fuel_system/calcs.html 38 lb = injectors at 80% duty cycle / 43 lb / .5 BSFC pressure are good for 242 = HP. The 440cc/42 lb injecors are good for 267 HP. =20 Also check out RC Engineering which is the most accepted expert that = I know of (http://www.rceng.com/technical.htm#WORKSHEET). Using the = same assumptions the 38 lb injectors are good for 242 HP and the 42 lb = injectors are also good for 267 HP. Looks like these guys are using the = same formulas - good to see consistency from 2 different sources. Lastly, note that injectors should not be run continuously over 80% = duty cycle or they will overheat and fail. A smaller is better when it = comes to idle control. DO NOT forget this part of the equation. = Lastly, at cruise altitudes the injector cycle rate decreases as the HP = requirement decreases so at 8000 ft the duty cycle of the injectors will = only be 60 % which is very safe for sustained operation. Call me if you = want to discuss this. Go play with the calculators posted above (which = George has already done). =20 Ken Powell=20 Bryant, Arkansas=20 501-847-4721 ------=_NextPart_000_0062_01C4FFE8.35BB4F20 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

George, my fuel pressure gauge reads = between 40 and=20 43 psi depending on whether I have one or both pumps on. I fly = with 40 psi=20 (one pump). My pump (with no flow) will give a pressure of = 80 psi,=20 but a regulator keeps it at 40-43 psi. I generally check my pumps = for=20 their no-flow pressure and have noticed over the 6 years that the = pressure of=20 the main pump has decreased from 80 psi to 60 psi - so getting near = replacement=20 time. The spare pump still produces 80 psi - less wear as it is = normally=20 only on for take off and landing.

Ed A

----- Original Message -----
From:=20 George=20 Lendich
To: Rotary motors in = aircraft

Sent: Friday, January 21, 2005 = 5:52=20 PM

Subject: [FlyRotary] Re: Fuel = Injector=20 Sizing

Ken and Ed Anderson.

Your info and advice is well = recieved and=20 timely for me - I didn't know what to use, now at least I = can talk=20 with some knowledge to suppliers.

One small question if I may - what = is the fuel=20 rail pressure usually?

Thanks again!

George ( down under)

Hi Jerry and George,

The debate over the optimal injector size has been going on for = years. I personally plan to use 400cc/38 lb or 440cc/42 lb = Ford=20 injectors. According to http:= //www.maxcooper.com/rx7/how-to/fuel_system/calcs.html 38=20 lb injectors at 80% duty cycle / 43 lb / .5 BSFC pressure are = good for=20 242 HP. The 440cc/42 lb injecors are good for 267 HP. =

Also check out RC Engineering which is the most accepted expert = that I=20 know of (http://www.rceng.co= m/technical.htm#WORKSHEET). =20 Using the same assumptions the 38 lb injectors are good for 242 HP = and the=20 42 lb injectors are also good for 267 HP. Looks like these = guys are=20 using the same formulas - good to see consistency from 2 different=20 sources.

Lastly, note that injectors should not be run continuously over = 80%=20 duty cycle or they will overheat and fail. A smaller is better = when it=20 comes to idle control. DO NOT forget this part of the = equation. =20 Lastly, at cruise altitudes the injector cycle rate decreases as the = HP=20 requirement decreases so at 8000 ft the duty cycle of the injectors = will=20 only be 60 % which is very safe for sustained operation. Call = me if=20 you want to discuss this. Go play with the calculators posted = above=20 (which George has already done).

Ken Powell
Bryant, Arkansas
501-847-4721

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