X-Virus-Scanned: clean according to Sophos on Logan.com From: "William Jepson" Received: from mail-wm0-f44.google.com ([74.125.82.44] verified) by logan.com (CommuniGate Pro SMTP 6.1.6) with ESMTPS id 8116078 for flyrotary@lancaironline.net; Fri, 30 Oct 2015 17:21:02 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.82.44; envelope-from=wrjjrs@gmail.com Received: by wmff134 with SMTP id f134so20737333wmf.1 for ; Fri, 30 Oct 2015 14:20:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; bh=XKDNXgQweoYVK6PP6jwUACzoOFcTjhQkmLGKelPlMuY=; b=DmAjOFOUws6mA1GXJiwO35Oq166ObFo6w8rfY1YxAZsfQOYXFBz6KhHvNmB+/SY74q MFbkHk0IqWCTmdyvUd2XpXFgon9dLgfoDKoRIB5CbInbxT9Xhnuq+0QyzU9TY0HFjQNJ iP1Bb05l8fHOYiuR7Jprm0DoRcTT62E0kqF2Ta7h2elw5Ed+MyAxv+ee05TwdmAnLwYo ifCJ9UAZEPdJ0IXCR+PzSwyciTWop5W760V3IsFQ/oBURaNzXMz3m+GI7w8gSr1Q+51F aAwnMzsC7sbri8B2xafVNn4wjXV7cuIomBL3ChKCgAtFFrcAC54ncJ0O5SFPO51wNdNG 1C/w== MIME-Version: 1.0 X-Received: by 10.28.137.211 with SMTP id l202mr334713wmd.90.1446240045358; Fri, 30 Oct 2015 14:20:45 -0700 (PDT) Received: by 10.27.145.16 with HTTP; Fri, 30 Oct 2015 14:20:45 -0700 (PDT) Received: by 10.27.145.16 with HTTP; Fri, 30 Oct 2015 14:20:45 -0700 (PDT) In-Reply-To: References: Date: Fri, 30 Oct 2015 14:20:45 -0700 Message-ID: Subject: Re: [FlyRotary] Re: 20B with RD-1C Prop Options To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=001a1144449629e66405235900a7 --001a1144449629e66405235900a7 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable James, a side port 20B with a good intake and exhaust can reasonably expect to see about 300 HP at 7000. Mistral's 3 rotor was right there. A peripheral port version quite a bit more. For an aircraft I suggest the p-port. There is almost no down side. My biggest reason is the intake is sooo much easier. They are more efficient in the range we use in aircraft anyway. Bill Jepson On Oct 30, 2015 8:13 AM, "James R. Osborn" wrote: > Hi Bill, > > Yeah after I sent that I realized slip was a much smaller difference. Th= e > difference between top speed and standing still is 100% slip! > > I don=E2=80=99t really know what to expect for HP. I threw those numbers= out > there for feedback. So what numbers say for unported site port, medium > street port side port, and peripheral port on a 20B can we reasonably > achieve? > > Thanks for more input and numbers. It will be interesting to try to work > it out on the ground and the more I think about it, adjustability will be= a > real big help. I did recall correctly that a friend has an old dyno I ca= n > borrow. So I guess I will move in that direction first and set the prop > selection aside for now. > > My plan is to buy an in progress RV-10, hopefully way past 50%. I really > don=E2=80=99t want to start from scratch; we have only one lifetime - 220= 00 days as > the song goes (maybe more like 28000 days now days :). > > =E2=80=94 James > > P.S. Thanks to you Charlie too and for the invite. Alas I am pretty far > West in the SF Bay area. Someday I hope to make it to some of the rotary > gatherings back East and South. > > > On Oct 29, 2015, at 9:33 PM, Bill Bradburry > wrote: > > > > James, > > There could be some slip involved, but it is mostly the change in angle > of > > attack as the prop disc is moved forward thru the air. > > > > If you can stand the expense, I recommend you get some kind of in fligh= t > > adjustable prop. The rotary power output is really affected by rpm and > > being able to adjust it in flight is very helpful. > > I also recommend you set a max take off rpm target of 2500 prop and 712= 5 > > engine. There are several good reasons for this not the least of which > is > > that the EC-2/3 has a cutoff at 7500 rpm. (Tracy can straighten me out > here > > if needed) > > If you dyno the engine be sure and let us know what you get. I don't > think > > you will be anywhere near those HP numbers you quote. Also when you ge= t > up > > to altitude and cut the rpm back to 48-5200, you will really be reducin= g > the > > output. If you leave the engine at 7125 rpm and climb to 8000 ft, you > will > > be producing 75%, if you then reduce the rpm to 4800, I don't know what > your > > percent power might be...but a heck of a lot lower than 75%. > > > > Do you plan to try and buy a completed airframe? It sometimes takes a > > surprising length of time to build one. Ask me how I know. :>) > > > > Bill > > > > -----Original Message----- > > From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] > > Sent: Thursday, October 29, 2015 9:20 PM > > To: Rotary motors in aircraft > > Subject: [FlyRotary] Re: 20B with RD-1C Prop Options > > > > Thanks for the input Tracy! So is the difference between top speed rpm > and > > static rpm the "slip"? > > > >> On Oct 29, 2015, at 6:32 PM, Tracy 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. Tha= t > > 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's 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't > > 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 evalua= te > > 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 (usin= g > 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 stati= c > > 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 woul= d > 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 howeve= r > my > > power plant turns out? Would the extra complexity be worth it? For th= e > > ground adjustable one, I am thinking the process would be: 1. select t= he > > "correct" 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 reasonab= ly > > efficient setting for 75% cruise? Am I thinking about this clearly? A= ll > > opinions are welcome. > >>> > >>> There's a lot for you to chew on! > >>> > >>> - James > >>> > >>> > >>> -- > >>> Homepage: http://www.flyrotary.com/ > >>> Archive and UnSub: > > http://mail.lancaironline.net:81/lists/flyrotary/List.html > >> > >> -- > >> Homepage: http://www.flyrotary.com/ > >> Archive and UnSub: > > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > > > > -- > > Homepage: http://www.flyrotary.com/ > > Archive and UnSub: > > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > > > > -- > > Homepage: http://www.flyrotary.com/ > > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > --001a1144449629e66405235900a7 Content-Type: text/html; charset=UTF-8 Content-Transfer-Encoding: quoted-printable

James, a side port 20B with a good intake and exhaust can re= asonably expect to see about 300 HP at 7000. Mistral's 3 rotor was righ= t there. A peripheral port version quite a bit more. For an aircraft I sugg= est the p-port. There is almost no down side. My biggest reason is the inta= ke is sooo much easier. They are more efficient in the range we use in airc= raft anyway.

Bill Jepson

On Oct 30, 2015 8:13 AM, "James R. Osborn&q= uot; <flyrotary@lancairon= line.net> wrote:
Hi Bill,

Yeah after I sent that I realized slip was a much smaller difference.=C2=A0= The difference between top speed and standing still is 100% slip!

I don=E2=80=99t really know what to expect for HP.=C2=A0 I threw those numb= ers out there for feedback.=C2=A0 So what numbers say for unported site por= t, medium street port side port, and peripheral port on a 20B can we reason= ably achieve?

Thanks for more input and numbers.=C2=A0 It will be interesting to try to w= ork it out on the ground and the more I think about it, adjustability will = be a real big help.=C2=A0 I did recall correctly that a friend has an old d= yno I can borrow.=C2=A0 So I guess I will move in that direction first and = set the prop selection aside for now.

My plan is to buy an in progress RV-10, hopefully way past 50%.=C2=A0 I rea= lly don=E2=80=99t want to start from scratch; we have only one lifetime - 2= 2000 days as the song goes (maybe more like 28000 days now days :).

=E2=80=94 James

P.S.=C2=A0 Thanks to you Charlie too and for the invite.=C2=A0 Alas I am pr= etty far West in the SF Bay area.=C2=A0 Someday I hope to make it to some o= f the rotary gatherings back East and South.

> On Oct 29, 2015, at 9:33 PM, Bill Bradburry <flyrotary@lancaironline.net> wrote:
>
> James,
> There could be some slip involved, but it is mostly the change in angl= e of
> attack as the prop disc is moved forward thru the air.
>
> If you can stand the expense, I recommend you get some kind of in flig= ht
> adjustable prop.=C2=A0 The rotary power output is really affected by r= pm and
> being able to adjust it in flight is very helpful.
> I also recommend you set a max take off rpm target of 2500 prop and 71= 25
> engine.=C2=A0 There are several good reasons for this not the least of= which is
> that the EC-2/3 has a cutoff at 7500 rpm. (Tracy can straighten me out= here
> if needed)
> If you dyno the engine be sure and let us know what you get.=C2=A0 I d= on't think
> you will be anywhere near those HP numbers you quote.=C2=A0 Also when = you get up
> to altitude and cut the rpm back to 48-5200, you will really be reduci= ng the
> output.=C2=A0 If you leave the engine at 7125 rpm and climb to 8000 ft= , you will
> be producing 75%, if you then reduce the rpm to 4800, I don't know= what your
> percent power might be...but a heck of a lot lower than 75%.
>
> Do you plan to try and buy a completed airframe?=C2=A0 It sometimes ta= kes a
> surprising length of time to build one.=C2=A0 Ask me how I know.=C2=A0= :>)
>
> Bill
>
> -----Original Message-----
> From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
> Sent: Thursday, October 29, 2015 9:20 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] Re: 20B with RD-1C Prop Options
>
> Thanks for the input Tracy!=C2=A0 So is the difference between top spe= ed rpm and
> static rpm the "slip"?
>
>> On Oct 29, 2015, at 6:32 PM, Tracy <flyrotary@lancaironline.net> wrote:
>>
>> Hi James,
>>=C2=A0 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.= =C2=A0 Would
> recommend propping for a max power at top speed rpm of about 7000.=C2= =A0 That
> will give you a static rpm of around 6000.
>>
>> Will get those instruction manuals you asked about to you next tim= e 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.=C2=A0 I sourced Bobby&#= 39;s spare 20B /
> RD-1C combo and my plan is to work on the motor first, kind of bass-ac= kward
> but that is what I am doing.=C2=A0 My plan is to build a motor/mount t= est stand
> and work everything out on the ground before I ever put it in an airfr= ame.
> I plan to set it up NA using the existing side port configuration.=C2= =A0 I don't
> know if it is ported - I am going to attempt to determine this by insp= ection
> without cracking it open and doing a dynamic compression test to evalu= ate
> the health of the motor.=C2=A0 If it is necessary to entirely rebuild = the motor,
> I would probably go PP.=C2=A0 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.=C2=A0 H= ow do these
> numbers sound to you all?
>>>
>>> I will be looking for a way to dyno it, hopefully borrow one t= o get some
> data.=C2=A0 But I was also thinking about just getting an appropriate = fixed pitch
> prop and working through the bugs based on static run ups.=C2=A0 I lik= e the idea
> of a three blade prop.=C2=A0 I like the idea of optimizing for cruise = at 75%, say
> 5800 rpm which would put full throttle at 7733 rpm on the 20B.=C2=A0 A= t 5800 rpm,
> the prop would be spinning 2035 rpm and at full throttle 2713 rpm (usi= ng the
> 2.85 ratio RD-1C PSRU).=C2=A0 Do all these numbers sound about right?<= br> >>>
>>> If so, then how do I choose a prop that will result in 2713 rp= m static
> run up at full throttle, but be tuned for efficiency at 2035 rpm cruis= e?=C2=A0 I
> am assuming at these reasonable RPMs that it will be a larger swing an= d the
> three blade makes sense - what do you think?=C2=A0 Is there a convenie= nt way to
> find props out there that will work at the target full throttle HP of = 275 or
> 325?=C2=A0 Also if you guys have any good resources to learn about how= to figure
> these things out (books, web pages, online calculators, etc.) that wou= ld be
> great!
>>>
>>> Another option might be to go with something like the IVOPROP = Magnum,
> either ground adjustable or electric inflight adjustable.=C2=A0 What d= o you guys
> think of these?=C2=A0 Would the adjustability really help me adapt to = however my
> power plant turns out?=C2=A0 Would the extra complexity be worth it?= =C2=A0 For the
> ground adjustable one, I am thinking the process would be:=C2=A0 1. se= lect the
> "correct" swing (how?) and go for three blades, 2) use groun= d adjustability
> and work up to THE pitch while I tune the motor until I achieve full > throttle static run up around 7700 RPM.=C2=A0 Will this result in a re= asonably
> efficient setting for 75% cruise?=C2=A0 Am I thinking about this clear= ly?=C2=A0 All
> opinions are welcome.
>>>
>>> There's a lot for you to chew on!
>>>
>>> - James
>>>
>>>
>>> --
>>> Homepage:=C2=A0 http://www.flyrotary.com/
>>> Archive and UnSub:
> http://mail.lancaironline.net:81/list= s/flyrotary/List.html
>>
>> --
>> Homepage:=C2=A0 http://www.flyrotary.com/
>> Archive and UnSub:
> http://mail.lancaironline.net:81/list= s/flyrotary/List.html
>
>
> --
> Homepage:=C2=A0 http://www.flyrotary.com/
> Archive and UnSub:
> http://mail.lancaironline.net:81/list= s/flyrotary/List.html
>
>
> --
> Homepage:=C2=A0 http://www.flyrotary.com/
> Archive and UnSub:=C2=A0 =C2=A0http:/= /mail.lancaironline.net:81/lists/flyrotary/List.html


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