Return-Path: Received: from [199.185.220.240] (HELO priv-edtnes51.telusplanet.net) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2908458 for flyrotary@lancaironline.net; Sun, 28 Dec 2003 15:48:59 -0500 Received: from Endurance ([207.194.22.106]) by priv-edtnes51.telusplanet.net (InterMail vM.6.00.05.02 201-2115-109-103-20031105) with SMTP id <20031228204855.MDSP19121.priv-edtnes51.telusplanet.net@Endurance> for ; Sun, 28 Dec 2003 13:48:55 -0700 From: "Haywire" To: "Rotary motors in aircraft" Subject: RE: [FlyRotary] Re: Fuel Coolers Date: Sun, 28 Dec 2003 12:48:49 -0800 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_002B_01C3CD40.F09C6C10" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook IMO, Build 9.0.2416 (9.0.2910.0) In-reply-to: X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 Importance: Normal This is a multi-part message in MIME format. ------=_NextPart_000_002B_01C3CD40.F09C6C10 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Glad to hear your incident did nothing more than re-arrange your seat cushion. I have never had a situation of impending vapor lock (such as caviation of the EFI pumps) that turning on the boost pump did not resolve. I do however, have my fuel pumps and header tank shielded with a fiberglass box covered with aluminum foil. I also have an NACA duct funneling outside air to the box. So I think your plans would certainly help the situation. Plus, you may have a bit more heat under you cowl what with the turbocharger. Other than my header pipe which do a 90 deg bend and out from the cowl - nothing much of a heat producer, also I do have louvers on both sides as well as a rather large opening on the bottom. Hi Ed; Fortunately our airport is very ideal for flight testing, with 3 separate, long runways and a relatively low amount of traffic. I try to do my flights when there is little traffic and I always maintain gliding distance to a runway. One of the benefits of the turbocharger and the constant speed IVO prop is that I can reach circuit height before I reach the end of the runway, allowing me to maintain gliding distance to at least one of the 6 runways at all times and I've practiced this as well. I'm aware of the "oh shit, this can't really be happening to me" time lag that happens before pilots take action, but I feel I was ready as I run these scenarios through my mind, before every flight, so it was an automatic reaction to quickly assess my options and take the best one. While I'm pleased with the way I handled it, I'm very angry with myself for not recognizing the vapour press situation developing sooner. As you may recall, we discussed your fuel system off-line way back when I was still developing mine and I felt that a larger header tank located aft of the firewall would reduce or eliminate the vapour issues while adding the benefit of a useable reserve. As I've just demonstrated, this is not the case. I wasn't aware that your system is shielded, so this reaffirms my decision to do this as well. The turbo certainly adds to the heat creating problems, which is ironic in that it also allows me to quickly climb to a safe altitude in case of problems, which it is adding to... hmmmnn... it's a vicious circle. I had earlier considered adding louvers to the side as you have, but a post from someone indicating that louvers are considered to be very high in drag, held off my decision to proceed, but I'm again considering this. Does anybody know of a source for an off-the-shelf louver? I had considered a fuel line cooler (which they do make), but unless you are funneling cool outside air to it (and no inside hot air) then it could make the problem worst by picking up more heat from the hotter under the cowl air. In any case, I have not tried a fuel line cooler, but would think that provided with cooling air, its couldn't hurt. I think that by ducting cool air through a fuel cooler at the inlet to the shroud around the fuel components, it should adequately cool the fuel without significantly heating the cooling air allowing plenty of cooling for the pumps and filters. I just have to find a small enough cooler to do the job. I also use a gascolator on one of my fuel lines, which I'm considering removing. I have water drains on each tank and a sump with a drain on my header tank, so I've never seen a single drop of water when draining my gascolator. How large is your cooling duct to your shroud over the fuel pumps? Where do you have your inlet for this cooling air? I originally considered ducting from the rad inlets, but I don't want to be stealing any of this cooling air, so am considering a small NACA duct on the side. Leon has sent me an off-line reply with a few additional suggestions as well. I'm considering replumbing the header tank vent line (which is normally closed), back to one of the wing tanks, instead of to the vent line header. This would allow the boost pump to continually recirc cool fuel to the header tank rather than just pressurizing it. This would also allow me to close this vent/recirc line when I do want to pressurize the header tank. The reason that I originally opted to use a header tank was it seemed at first to be the simplest way to manage 6 fuel tanks without the hassle of returning to a single tank and transferring fuel as others have done. I've now found that it requires much more management than anticipated and is becoming much more complicated. If I was starting over again, I would certainly reconsider this idea. Thanks for any & all input. S. Todd Bartrim Turbo 13B RV-9Endurance C-FSTB http://www3.telus.net/haywire/RV-9/C-FSTB.htm "Whatever you vividly imagine, Ardently desire, Sincerely believe in, Enthusiastically act upon, Must inevitably come to pass". ------=_NextPart_000_002B_01C3CD40.F09C6C10 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Glad = to hear your=20 incident did nothing more than re-arrange your seat cushion.  I = have never=20 had a situation of impending vapor lock (such as caviation of the EFI = pumps)=20 that turning on the boost pump did not resolve.  I do however, have = my fuel=20 pumps and header tank shielded with a fiberglass box covered with = aluminum=20 foil.  I also have an NACA duct funneling outside air to the = box.  So=20 I think your plans would certainly help the situation.  Plus, you = may have=20 a bit more heat under you cowl what with the turbocharger.  Other = than my=20 header pipe which do a 90 deg bend and out from the cowl - nothing = much of=20 a heat producer, also I do have louvers on both sides as well as a = rather large=20 opening on the bottom.
 
Hi=20 Ed;
    Fortunately our airport is = very=20 ideal for flight testing, with 3 separate, long runways and a relatively = low=20 amount of traffic. I try to do my flights when there is little traffic = and I=20 always maintain gliding distance to a runway. One of the benefits = of the=20 turbocharger and the constant speed IVO prop is that I can reach circuit = height=20 before I reach the end of the runway, allowing me to maintain gliding = distance=20 to at least one of the 6 runways at all times and I've practiced this as = well.=20 I'm aware of the "oh shit, this can't really be happening to me" time = lag that=20 happens before pilots take action, but I feel I was ready as I run these = scenarios through my mind, before every flight, so it was an = automatic=20 reaction to quickly assess my options and take the best one. While I'm = pleased=20 with the way I handled it, I'm very angry with myself for not = recognizing the=20 vapour press situation developing sooner.
    As you may recall, we = discussed your=20 fuel system off-line way back when I was still developing mine and I = felt that a=20 larger header tank located aft of the firewall would reduce or eliminate = the=20 vapour issues while adding the benefit of a useable reserve. As I've = just=20 demonstrated, this is not the case. I wasn't aware that your system is = shielded,=20 so this reaffirms my decision to do this as well. The turbo certainly = adds to=20 the heat creating problems, which is ironic in that it also allows me to = quickly=20 climb to a safe altitude in case of problems, which it is adding to... = hmmmnn...=20 it's a vicious circle.
    I had earlier considered = adding=20 louvers to the side as you have, but a post from someone indicating that = louvers=20 are considered to be very high in drag, held off my decision to proceed, = but I'm=20 again considering this. Does anybody know of a source for an = off-the-shelf=20 louver?
 
  = I had=20 considered a fuel line cooler (which they do make), but unless you are = funneling=20 cool outside air to it (and no inside hot air) then it could make the = problem=20 worst by picking up more heat from the hotter under the cowl air.  = In any=20 case, I have not tried a fuel line cooler, but would think that provided = with=20 cooling air, its couldn't hurt.
 
    I think that by ducting cool air through a = fuel cooler=20 at the inlet to the shroud around the fuel components, it should = adequately cool=20 the fuel without significantly heating the cooling air allowing plenty = of=20 cooling for the pumps and filters. I just have to find a small enough = cooler to=20 do the job. I also use a gascolator on one of my fuel lines, which I'm=20 considering removing. I have water drains on each tank and a sump with a = drain=20 on my header tank, so I've never seen a single drop of water when = draining my=20 gascolator.
    How large is your cooling duct to your shroud = over the fuel=20 pumps? Where do you have your inlet for this cooling air? I = originally=20 considered ducting from the rad inlets, but I don't want to be stealing = any of=20 this cooling air, so am considering a small NACA duct on the=20 side.
    Leon has sent me an off-line reply with a few = additional=20 suggestions as well. I'm considering replumbing the header tank vent = line (which=20 is normally closed), back to one of the wing tanks, instead of to the = vent line=20 header. This would allow the boost pump to continually recirc cool fuel = to the=20 header tank rather than just pressurizing it. This would also allow me = to close=20 this vent/recirc line when I do want to pressurize the header=20 tank.
    The reason that I originally opted to use a = header tank was=20 it seemed at first to be the simplest way to manage 6 fuel tanks without = the=20 hassle of returning to a single tank and transferring fuel as others = have done.=20 I've now found that it requires much more management than anticipated = and is=20 becoming much more complicated. If I was starting over again, I = would=20 certainly reconsider this idea.
 
Thanks=20 for any & all input.

S. Todd Bartrim
Turbo 13B = RV-9Endurance
C-FSTB
http://www3.telus.net/haywire/RV-9/C-FSTB.htm

=   =20 "Whatever you vividly imagine, Ardently desire, Sincerely believe in,=20 Enthusiastically act upon, Must inevitably come to pass".=20

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