X-Virus-Scanned: clean according to Sophos on Logan.com From: "Thomas Giddings" Received: from elasmtp-junco.atl.sa.earthlink.net ([209.86.89.63] verified) by logan.com (CommuniGate Pro SMTP 6.1.6) with ESMTP id 8115273 for flyrotary@lancaironline.net; Fri, 30 Oct 2015 12:36:29 -0400 Received-SPF: none receiver=logan.com; client-ip=209.86.89.63; envelope-from=n360tg@earthlink.net DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=dk20050327; d=earthlink.net; b=BPfkd8vlLGJu/+g+PUKzSt3uTsxyuD1N7rRMo7LNepDf12ymYPeBeKknWKqEKeh9; h=Received:From:Mime-Version:Content-Type:Subject:Date:In-Reply-To:To:References:Message-Id:X-Mailer:X-ELNK-Trace:X-Originating-IP; Received: from [166.172.185.20] (helo=[172.20.10.2]) by elasmtp-junco.atl.sa.earthlink.net with esmtpsa (TLSv1:AES128-SHA:128) (Exim 4.67) (envelope-from ) id 1ZsCex-0002W1-9t for flyrotary@lancaironline.net; Fri, 30 Oct 2015 11:36:11 -0500 Mime-Version: 1.0 (Apple Message framework v1085) Content-Type: multipart/alternative; boundary=Apple-Mail-9--235665509 Subject: Re: [FlyRotary] Re: 20B with RD-1C Prop Options Date: Fri, 30 Oct 2015 12:36:09 -0400 In-Reply-To: To: "Rotary motors in aircraft" References: Message-Id: X-Mailer: Apple Mail (2.1085) X-ELNK-Trace: 77b0437ff618fec294f5150ab1c16ac07fe20a7848b236adb617e217553e73c63fe4f17c7753124b350badd9bab72f9c350badd9bab72f9c350badd9bab72f9c X-Originating-IP: 166.172.185.20 --Apple-Mail-9--235665509 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset=windows-1252 James: If you need a proven intake and throttle body set up for your = 20B. I have one ready to go.Let me know KIND REGARDS Thomas Giddings n360tg@earthlink.net 727 858 1772 On Oct 29, 2015, at 10:19 PM, James R. Osborn wrote: > Thanks for the input Tracy! So is the difference between top speed = rpm and static rpm the =93slip=94? >=20 >> On Oct 29, 2015, at 6:32 PM, Tracy = wrote: >>=20 >> Hi James, >> HP targets sound doable, but those rpm numbers are probably off. = Remember that with a fixed pitch prop, hp varies as the CUBE of rpm. = Would recommend propping for a max power at top speed rpm of about 7000. = That will give you a static rpm of around 6000. >>=20 >> Will get those instruction manuals you asked about to you next time = I'm in the office. >>=20 >> Tracy >>=20 >> Sent from my iPad >>=20 >>> On Oct 29, 2015, at 16:22, James R. Osborn = wrote: >>>=20 >>> Hi guys, >>>=20 >>> So I am going to be building an RV-10. I sourced Bobby=92s spare = 20B / RD-1C combo and my plan is to work on the motor first, kind of = bass-ackward but that is what I am doing. My plan is to build a = motor/mount test stand and work everything out on the ground before I = ever put it in an airframe. I plan to set it up NA using the existing = side port configuration. I don=92t know if it is ported - I am going to = attempt to determine this by inspection without cracking it open and = doing a dynamic compression test to evaluate the health of the motor. = If it is necessary to entirely rebuild the motor, I would probably go = PP. So I am thinking the target HP as it is would be in the 275 HP = range and probably 325 HP if it ends up being a PP. How do these = numbers sound to you all? >>>=20 >>> I will be looking for a way to dyno it, hopefully borrow one to get = some data. But I was also thinking about just getting an appropriate = fixed pitch prop and working through the bugs based on static run ups. = I like the idea of a three blade prop. I like the idea of optimizing = for cruise at 75%, say 5800 rpm which would put full throttle at 7733 = rpm on the 20B. At 5800 rpm, the prop would be spinning 2035 rpm and at = full throttle 2713 rpm (using the 2.85 ratio RD-1C PSRU). Do all these = numbers sound about right? >>>=20 >>> If so, then how do I choose a prop that will result in 2713 rpm = static run up at full throttle, but be tuned for efficiency at 2035 rpm = cruise? I am assuming at these reasonable RPMs that it will be a larger = swing and the three blade makes sense - what do you think? Is there a = convenient way to find props out there that will work at the target full = throttle HP of 275 or 325? Also if you guys have any good resources to = learn about how to figure these things out (books, web pages, online = calculators, etc.) that would be great! >>>=20 >>> Another option might be to go with something like the IVOPROP = Magnum, either ground adjustable or electric inflight adjustable. What = do you guys think of these? Would the adjustability really help me = adapt to however my power plant turns out? Would the extra complexity = be worth it? For the ground adjustable one, I am thinking the process = would be: 1. select the =93correct=94 swing (how?) and go for three = blades, 2) use ground adjustability and work up to THE pitch while I = tune the motor until I achieve full throttle static run up around 7700 = RPM. Will this result in a reasonably efficient setting for 75% cruise? = Am I thinking about this clearly? All opinions are welcome. >>>=20 >>> There=92s a lot for you to chew on! >>>=20 >>> =97 James >>>=20 >>>=20 >>> -- >>> Homepage: http://www.flyrotary.com/ >>> Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html >>=20 >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html >=20 >=20 > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html --Apple-Mail-9--235665509 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=windows-1252
KIND = REGARDS
Thomas Giddings
72= 7 858 1772



On Oct 29, 2015, at 10:19 PM, James R. = Osborn wrote:

Thanks for the input Tracy!  So is the = difference between top speed rpm and static rpm the = =93slip=94?

On Oct 29, 2015, at 6:32 = PM, Tracy <flyrotary@lancaironline.net> wrote:

Hi = James,
 HP targets sound = doable, but those rpm numbers are probably off.  Remember that with = a fixed pitch prop, hp varies as the CUBE of rpm.  Would recommend = propping for a max power at top speed rpm of about 7000.  That will = give you a static rpm of around 6000.

Will get those = instruction manuals you asked about to you next time I'm in the = office.

Tracy

Sent from my = iPad

On Oct 29, 2015, at 16:22, James R. Osborn <flyrotary@lancaironline.net> wrote:

Hi = guys,

So I am going to be building an = RV-10.  I sourced Bobby=92s spare 20B / RD-1C combo and my plan is = to work on the motor first, kind of bass-ackward but that is what I am = doing.  My plan is to build a motor/mount test stand and work = everything out on the ground before I ever put it in an airframe. =  I plan to set it up NA using the existing side port configuration. =  I don=92t know if it is ported - I am going to attempt to = determine this by inspection without cracking it open and doing a = dynamic compression test to evaluate the health of the motor.  If = it is necessary to entirely rebuild the motor, I would probably go PP. =  So I am thinking the target HP as it is would be in the 275 HP = range and probably 325 HP if it ends up being a PP.  How do these = numbers sound to you all?

I will be looking for a way to = dyno it, hopefully borrow one to get some data.  But I was also = thinking about just getting an appropriate fixed pitch prop and working = through the bugs based on static run ups.  I like the idea of a = three blade prop.  I like the idea of optimizing for cruise at 75%, = say 5800 rpm which would put full throttle at 7733 rpm on the 20B. =  At 5800 rpm, the prop would be spinning 2035 rpm and at full = throttle 2713 rpm (using the 2.85 ratio RD-1C PSRU).  Do all these = numbers sound about right?

If so, then how do I choose a = prop that will result in 2713 rpm static run up at full throttle, but be = tuned for efficiency at 2035 rpm cruise?  I am assuming at these = reasonable RPMs that it will be a larger swing and the three blade makes = sense - what do you think?  Is there a convenient way to find props = out there that will work at the target full throttle HP of 275 or 325? =  Also if you guys have any good resources to learn about how to = figure these things out (books, web pages, online calculators, etc.) = that would be great!

Another option might be to go = with something like the IVOPROP Magnum, either ground adjustable or = electric inflight adjustable.  What do you guys think of these? =  Would the adjustability really help me adapt to however my power = plant turns out?  Would the extra complexity be worth it?  For = the ground adjustable one, I am thinking the process would be:  1. = select the =93correct=94 swing (how?) and go for three blades, 2) use = ground adjustability and work up to THE pitch while I tune the motor = until I achieve full throttle static run up around 7700 RPM.  Will = this result in a reasonably efficient setting for 75% cruise?  Am I = thinking about this clearly?  All opinions are = welcome.

There=92s a lot for you to chew = on!

=97 = James


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