X-CGP-ClamAV-Result: CLEAN X-VirusScanner: Niversoft's CGPClamav Helper v1.23.0 (ClamAV engine v0.103.0) X-Junk-Score: 0 [] X-KAS-Score: 0 [] From: "Charlie England ceengland7@gmail.com" Received: from mail-io1-f52.google.com ([209.85.166.52] verified) by logan.com (CommuniGate Pro SMTP 6.3.5) with ESMTPS id 376441 for flyrotary@lancaironline.net; Wed, 20 Oct 2021 12:02:06 -0400 Received-SPF: pass receiver=logan.com; client-ip=209.85.166.52; envelope-from=ceengland7@gmail.com Received: by mail-io1-f52.google.com with SMTP id s17so25198139ioa.13 for ; Wed, 20 Oct 2021 09:02:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to; bh=j9CKkJ30F6XX4hJw9OtQOy/GOZUYrnOa1UxUs1nwjuU=; b=HJBSs2ojsEziyDF/FyFNXzhq+K5f5saa28FOS6XXjsNb6PYCymOU1bXUF2yEp9yhrP 3ph1SLnENIJQVmPguIzwndW7dEwnPLkFLZWCtKleIlW8m+6XV5YauAGsKROkEcCWuqTk kiGf4jsolYacMSWN+orV8noafLRqcd4jn3Ek9wCjUYgAJUJ0C+fc7VQ7FFbeKAxvWw0h AXmebbXP3j/Cqg2bBojsn+luOs9WTkgJKP0ete7tVONalQYoWV6DiDayjH30jz1aGvz0 eNRcaNC1WQlrBYmyJw/Uiftu3gRFuQwZNR9zgZdtQUNY0A/haQXBxkB3btn7fyYS8COa HDyg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to; bh=j9CKkJ30F6XX4hJw9OtQOy/GOZUYrnOa1UxUs1nwjuU=; b=KX+Tf9WYq9aVnD6oHAUJo9FKMlCTsk1uVf1egyTVTKBR6GJ7tVQGbCHyEolrSrjEJI YgPGoE6Kz7EsIxGv6gR/zeUEsKrrmafvq/Df9WF8LMg+AiZsPuimjyQVl+DLcNlJgTMY JzPk5EJBQzS1cMHmCG3b2/+oYT+Wm1IXkQ3bgumWTj8FysG+OBS3oYamfIVBou8apYcj J0aiKgwu+Mwgv3LRWcJBoAY3zdmNj8f/rl4BOIijVqmeTjViVlu4nNfsFGbFRjp/m7F6 KOTKczfw8Gh462zzgdQkjxTOiokR5u5PPL9e8FXaqwfRp7MX7jL+52mI7GC4n+EBgU/i Dw/Q== X-Gm-Message-State: AOAM533ra9xtPqaDWvGWdrN2T+1jc8MJmMKCjeIz/3DAOkvk4tjz/bD0 ovmrgjpidnUGGCtlTcMOCk0yvG7LFP4fJ1XKM6lsVYa/ X-Google-Smtp-Source: ABdhPJxY9O4tGAJLD7f3KJAzSrpSoXgf6ZmAeuu+xe6fPk8PWJox0HwZQjT++MF1Kr+ORYWzE08RQKa0/ZIOuzL6dMs= X-Received: by 2002:a02:a38e:: with SMTP id y14mr152650jak.8.1634745708606; Wed, 20 Oct 2021 09:01:48 -0700 (PDT) MIME-Version: 1.0 References: In-Reply-To: Date: Wed, 20 Oct 2021 11:01:32 -0500 Message-ID: Subject: Re: [FlyRotary] Re: Ag Ops To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary="00000000000042782305cecae504" --00000000000042782305cecae504 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Hi Steve, I can't claim any expertise, but I do have some experience with various prop diameters on RVs. Van started out recommending 68" dia props on the 2 seat RVs. My 1st RV4 had a Warnke 72x72. With 160 HP, it had 1200-1500fpm climb and would cruise at 170 kts @ ~9.3 gph rich of peak, ~75% power for a Lyc 160. The cruise matched Van's numbers, and climb was at least as good, if not better than Van's numbers. After my partner in the RV damaged the Warnke, I replaced it with a 68" from another mfgr and the plane never performed as well in either cruise or climb. At one point, I tried a 76" dia IVO. Climb was incredible, but the plane would hit a wall at about 145-150 kts (known problem with IVO's blades; they don't have enough twist for high speed operation). Another data point: Van's current catalog lists a Hartzel 74" dia c/s prop for the 2 seat a/c and the f/p props are in the 72" dia range. My calculations on optimum dia & ratio for the Renesis are similar to yours. If you start with the Lyc-standard 2700 prop rpm, with the realization that 74" is not too large a diameter (for tip speed issues) at 2700, then the optimum ratio would be determined by your desired max engine rpm. With a controllable prop, you can give up a little bit in diameter & get back low speed thrust by going to flatter pitch & more HP. But if fixed pitch, I try for the largest dia I can safely fit on the plane. With a typical fast 2 seat homebuilt, gear leg length, not tip speed, will almost always be the limiting factor even at 2700+ rpm. The bigger the diameter, the better the low speed mass flow (thrust), and there will be little to no penalty at any cruise speed under the 180-190 kt range (well above 200 mph). The above assumes a properly designed prop, of course. One reason to desire that 2.4-2.5:1 ratio is that it gets prop rpm where the prop carver is used to working, and we're much more likely to get a usable prop on 1st try if he's in familiar territory. If you tell him, say, 200 HP @ 2700 prop rpm & cruise at 75% will be 170 kts, he'll likely be able to get it right, 1st try. If, on the other hand, you're telling him the same HP & speed, but you want, for instance, 76" dia & 2300 prop rpm, he's going to be guessing on how to carve the prop. Bottom line: I fit the largest dia I can safely swing, regardless of f/p or c/s (because low speed thrust will always improve with diameter increases), knowing that ground clearance will be a problem long before tip speed becomes an issue. If you haven't already bought the 72", I'd be asking them for a 76" if they'll sell you one and you can safely swing it on your plane. And be sure to tell them the actual rpm range where it will operate. Their 'stock' 72" for a Lyc will be sub-optimal turning in the ~2000 rpm range with a 2.85 drive, unless you intend to really flog the engine hard all the time & pour a lot of fuel through it. FWIW, Charlie On Tue, Oct 19, 2021 at 7:38 PM Stephen Izett stephen.izett@gmail.com < flyrotary@lancaironline.net> wrote: > Hi Andrew > > Continuing to fine tune the Renesis cooling system and aircraft. > Completing a new exhaust system after a leaking gasket warped a flange. > Last flight temps max=E2=80=99d at 91C (196F) on takeoff with 20C (68F)OA= T and we > got her up to 189knots but only 2600 feet due to cloud. > Learning that increasing the IAS by ~10knots in climb has a significant > effect on cooling. > > Also in the process of changing the current 66.5=E2=80=9D Airmasterto for= a 72=E2=80=9D MT > prop. > I only read after going with our gearbox/prop combination that Tracy > recommended only using the 2.85:1 with props of >=3D74=E2=80=9D > For those with expertise in this area, is it true that we should choose: > 1. Largest prop dimeter with acceptable clearance > 2. Target cruise tip speed of ~0.8-0.85 speed of sound for best efficienc= y > If this is correct then with a 72=E2=80=9D prop and a chosen engine redli= ne of > 7500 RPM (4 port Renesis) a better gearbox ratio would be ~2.5:1 > The 2.85:1 would be better suited to a 74-76=E2=80=9D prop at that redlin= e. > > Hope you have a great harvest and get back in the air soon Andrew. > > Steve > > > On 20 Oct 2021, at 7:52 am, Andrew Martin andrew@martinag.com.au < > flyrotary@lancaironline.net> wrote: > > Hi Steve, hows the Glasair going? I been away from flying for awhile, > hopefully back into it in new year. Did start mine recently after it been > sitting idle since feb 2020, So happy I persevered with the mazda, it > started & ran so sweet I contemplated doing a couple of circuits but for > the legalities. No MR and I need AFR first. > > Neil, not sure I agree with your rotor setup proposal, ( not that mine is > better) can get some weird aerodynamics with intermeshing rotors. > Whole thing of nurse cart & drone need to be a package, rotors will never > be stopped during refill so drone needs to land on roof of truck or trail= er > for refill from underneath to keep blades clear of dumbasses like me. > Truth be told, I dont think we can get anywhere near the efficiency of a > ground rig or Ag plane, we easily average 80 ha/hr each machine + nurse > cart, going to need a swarm of drones to get near this. But could be a fu= n > project. > Andrew > > On Tue, 19 Oct. 2021, 9:07 am Stephen Izett stephen.izett@gmail.com, < > flyrotary@lancaironline.net> wrote: > >> Good to hear your voice Andrew. >> My son-in-law in Kojonup would be very interested in what you guys are >> talking about. >> >> Cheers >> >> Steve Izett >> >> >> >>> >>> >> -- > Regards Andrew Martin Martin Ag > > > --00000000000042782305cecae504 Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable
Hi Steve,

I= can't claim any expertise, but I do have some experience with various = prop diameters on RVs. Van started out recommending 68" dia props on t= he 2 seat RVs. My 1st RV4 had a Warnke 72x72. With 160 HP, it had 1200-1500= fpm climb and would cruise at 170 kts=C2=A0@ ~9.3 gph rich of peak, ~75% po= wer for a Lyc 160. The cruise matched Van's numbers, and climb was at l= east as good, if not better than Van's numbers. After my partner in the= RV damaged the Warnke, I replaced it with a 68" from another mfgr and= the plane never performed as well in either cruise or climb. At one point,= I tried a 76" dia IVO. Climb was incredible, but the plane would=C2= =A0hit a=C2=A0wall at=C2=A0about 145-150 kts (known problem with IVO's = blades; they don't have enough=C2=A0twist for high speed operation). An= other data point: Van's current catalog lists a Hartzel 74" dia c/= s prop for the 2 seat a/c and the f/p props are in the 72" dia range.<= /div>

My calculations on optimu= m dia & ratio for the Renesis are similar to yours. If you start with t= he Lyc-standard 2700 prop rpm, with the realization that 74" is not to= o large a diameter (for tip speed issues) at 2700, then the optimum ratio w= ould be determined by your desired max engine rpm. With a controllable prop= , you can give up a little bit in diameter & get back low speed thrust = by going to flatter pitch & more HP. But if fixed pitch, I try for the = largest dia I can safely fit on the plane. With a typical fast 2 seat homeb= uilt, gear leg length, not tip speed, will almost always be the limiting fa= ctor even at 2700+ rpm. The bigger the diameter, the better the low speed m= ass flow (thrust), and there will be little to no penalty at any cruise spe= ed under the 180-190 kt range (well above 200 mph).=C2=A0

The above assumes a properly designed pr= op, of course. One reason to desire that 2.4-2.5:1 ratio is that it gets pr= op rpm where the prop carver is used to working, and we're much more li= kely to get a usable prop on 1st try if he's in familiar territory. If = you tell him, say, 200 HP=C2=A0@ 2700 prop rpm & cruise at 75% will be = 170 kts, he'll likely be able to get it right, 1st try. If, on the othe= r hand, you're telling him the same HP & speed, but you want, for i= nstance, 76" dia & 2300 prop rpm, he's going to be guessing on= how to carve the prop.

B= ottom line: I fit the largest dia I can safely swing, regardless of f/p or = c/s (because low speed thrust will always improve with diameter increases),= knowing that ground clearance will be a problem long before tip speed beco= mes an issue. If you haven't already bought the 72", I'd be as= king them for a 76" if they'll sell you one and you can safely swi= ng it on your plane. And be sure to tell them the actual rpm range where it= will operate. Their 'stock' 72" for a Lyc will be sub-optimal= turning in the ~2000 rpm range with a 2.85 drive, unless you intend to rea= lly flog the engine hard all the time & pour a lot of fuel through it.<= /div>

FWIW,

Charlie

On Tue, Oct 19, 2021 at 7:38 PM= Stephen Izett stephen.izett@gma= il.com <flyrotary@lan= caironline.net> wrote:
Hi Andrew

<= /div>
Continuing to fine tune the Renesis cooling system and aircraft.<= /div>
Completing a new exhaust system after a leaking gasket warped a f= lange.
Last flight temps max=E2=80=99d at 91C (196F) on takeoff w= ith 20C (68F)OAT and we got her up to 189knots but only 2600 feet due to cl= oud.
Learning that increasing the IAS by ~10knots in climb has a = significant effect on cooling.

Also in the process= of changing the current 66.5=E2=80=9D Airmasterto for a 72=E2=80=9D MT pro= p.
I only read after going with our gearbox/prop combination that= Tracy recommended only using the 2.85:1 with props of >=3D74=E2=80=9D
For those with expertise in this area, is it true that we should c= hoose:
1. Largest prop dimeter with acceptable clearance
2. Target cruise tip speed of ~0.8-0.85 speed of sound for best efficienc= y
If this is correct then with a 72=E2=80=9D prop and a chosen en= gine redline of 7500 RPM (4 port Renesis) a better gearbox ratio would be ~= 2.5:1
The 2.85:1 would be better suited to a 74-76=E2=80=9D prop = at that redline.

Hope you have a great harvest and= get back in the air soon Andrew.

Steve
=

On 20 Oct 2021, at 7= :52 am, Andrew Martin andrew@martinag.com.au <flyrotary@lancaironline.net> wrote:
Hi Steve, hows the Glasair going? I = been away from flying for awhile, hopefully back into it in new year. Did s= tart mine recently after it been sitting idle since feb 2020, So happy I pe= rsevered with the mazda, it started & ran so sweet I contemplated doing= a couple of circuits but for the legalities. No MR and I need AFR first.
Neil, not sure I agree with you= r rotor setup proposal, ( not that mine is better) can get some weird aerod= ynamics with intermeshing rotors.
Whole thing = of nurse cart & drone need to be a package, rotors will never be stoppe= d during refill so drone needs to land on roof of truck or trailer for refi= ll from underneath to keep blades clear of dumbasses like me.
Truth be told, I dont think we can get anywhere near the efficien= cy of a ground rig or Ag plane, we easily average 80 ha/hr each machine + n= urse cart, going to need a swarm of drones to get near this. But could be a= fun project.
Andrew
On Tue, 19 Oct. 2021, 9:07 am Stephen Izett stephen.ize= tt@gmail.com, <flyrotary@lancaironline.net&g= t; wrote:
Good to hear your voice Andrew.
My = son-in-law in Kojonup would be very interested in what you guys are talking= about.

Cheers

Steve Izet= t

=C2=A0


=

--
Regards Andrew Martin Martin Ag

--00000000000042782305cecae504--