X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao104.cox.net ([68.230.241.42] verified) by logan.com (CommuniGate Pro SMTP 5.3.2) with ESMTP id 4118783 for flyrotary@lancaironline.net; Tue, 09 Feb 2010 23:05:24 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.42; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao104.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20100210040448.FDNH16123.fed1rmmtao104.cox.net@fed1rmimpo01.cox.net> for ; Tue, 9 Feb 2010 23:04:48 -0500 Received: from willsPC ([68.105.86.80]) by fed1rmimpo01.cox.net with bizsmtp id g44m1d00T1k005Q0344nqq; Tue, 09 Feb 2010 23:04:48 -0500 X-VR-Score: -200.00 X-Authority-Analysis: v=1.1 cv=qY0/QvRffkjURHWZjC3q+nTs9PdPIIJxYa32KydkvE8= c=1 sm=1 a=TWlVO4UZOuUA:10 a=XruvlouZCDbGUgEaRUiNZQ==:17 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=ekHE3smAAAAA:20 a=UretUmmEAAAA:8 a=Ia-xEzejAAAA:8 a=8fvOh1mKAAAA:8 a=nUuTZ29dAAAA:8 a=zABoSsLVHRZJU1DE-7MA:9 a=SpYThmpbHKNLWR1O9e4A:7 a=Huxe06B-7LalwCD7PzGohS6tizMA:4 a=5zrLeAV0Z70A:10 a=1vhyWl4Y8LcA:10 a=EzXvWhQp4_cA:10 a=SVqzirnCOXUA:10 a=LGAdiCrTRWjgKaNH:21 a=a8uV_4ZEMbag0CaR:21 a=iH1zQb-0m45kbEDgZp0A:9 a=ErvOrtZc45TTiIwjUYoA:7 a=dPypr5OJjRALqW1j_AUcBrilDM0A:4 a=iVkDmfvjeKcA:10 a=XruvlouZCDbGUgEaRUiNZQ==:117 X-CM-Score: 0.00 Message-ID: <0BD4C84202F4457EA68672DFE2D40CB1@willsPC> From: "Mike Wills" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: N.A. Renesis to turbo Date: Tue, 9 Feb 2010 20:04:46 -0800 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00DE_01CAA9C3.20A8A300" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8089.726 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8089.726 This is a multi-part message in MIME format. ------=_NextPart_000_00DE_01CAA9C3.20A8A300 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Tracy, I've noted the RPM difference repeatedly so that I'm sure about. On the MP I have to admit I'm not all that certain. Pretty sure that = once it hits the max power point that there are no further changes in = MP. But I'll have to take a look and make some notes next flight. Two things make it problematic. I never really referred to my MP gauge = in my previous RV so when I designed my panel and ran out of space the = MP gauge ended up relegated to the center console and is a little = difficult to see in flight. The other problem is that I actually don't = have a real MP gauge - I cheaped out and used a good vacuum gauge that I = had laying around. I really need to change both these things. Mike From: Tracy Crook=20 Sent: Tuesday, February 09, 2010 5:20 AM To: Rotary motors in aircraft=20 Subject: [FlyRotary] Re: rpm vs Power was : Throttle limits was Re: N.A. = Renesis to turbo Ed's experience pretty much matches my own when changing gear drive = ratios. A little more top end. (Sun 100 results were 209 mph w/ 2.176 = drive vs 217.5 mph the next year with 2.85 drive.) Takeoff & climb = performance improved dramatically though. It's not an inexpensive = change though. What does mystify me is the small difference between Mike's static & top = end rpm. I got an 1100 rpm difference. 5200 vs 6300 with a 68 - 81 = Performance prop. Another detail I'm not certain about is whether Mike's manifold pressure = is or is not increasing during that last 1/3 - 1/2 throttle travel with = no power increase. Seems like he said it did go up but I'm not sure. = If it is going up, there is still something unexplained going on. What = was the MP doing Mike? Was it at full ambient at the point where the = rpm stopped increasing? Tracy On Tue, Feb 9, 2010 at 12:12 AM, Ed Anderson = wrote: Well, Mike, just for comparison, when I had a 2.17:1 and a 68 x72 Performance prop, 5200 -5400 rpm on a nominal 70deg day was what I got = for static. While I don't claim my set up was the best in the land, I think it was = a pretty fair set up. So I would say you are doing just fine. It does not matter how large a throttle body you have when the = manifold air density hits ambient or as close as it can given any losses in the = induction system - that's it. You can continue to open the throttle body, but = you will not get any more power. However, there is a way! Looking at some of the variables in the power equation we have: Power(HP) =3D Torque * rpm/ 5250, swapping some variables around we = get: RPM =3D Power/torque. So this indicates the rpm can increase if = either the power is increased or the torque is decreased. Well, it's difficult to increase the power by itself(unless you go to forced induction or = nitrous oxide) But one way to get more rpm (and ultimately more power) is to lower = the Torque load on the engine. Decreasing the Torque permits more engine = rpm even if power did not increase. However we know that more rpm =3D = more air =3D more power. The torque load on the engine caused by the prop decreases = as your gear ratio increases. By going to a 2.85:1 gear ratio that would reduce the load on the = engine by approx 25% (assuming the same prop at the same static rpm). Now the = rpm power relationship were linear (which it is not with a prop as the = load) then I should have gotten around 6650 rpm with the new gear box - well = not really - due to the cube root relationship between prop rpm and power, = it will be much less of an increase and due to the fact I put on a larger diameter prop. But in any case, all this theory aside, with the 2.85 and 74 x88 prop = I now get engine 6000 - 6200 rpm static or about an 13% increase in rpm. = So that's using use the same intake, throttle body and engine for both. = But now because the engine can turn faster (lesser prop load at any = specific rpm). Now the fact the engine is turning faster means it takes more airflow = to maintain the same (ambient) air density in the manifold. This is = because the higher engine rpm can "suck" that manifold volume (which didn't = change) down faster than it did before. This in turn means that the throttle = position has to be more open to let a sufficient increase in air flow need to = achieve and maintain that (hopefully) ambient air density in the manifold. So from what you are reporting, I really don't see anything poor about = your performance with your set up. In fact, it's pretty good. The new set up gave a noticeable benefit in take off performance (and = I do mean noticeable). However, the top end was relatively unaffected - = although I did measure an approx 4 mph increase in top aircraft speed. In any case, that is my experience. FWIW Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Mike Wills Sent: Monday, February 08, 2010 10:36 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Throttle limits was Re: N.A. Renesis to turbo Thanks Ed. Mentioned this a few months ago and was convinced at least = for the moment, to just fly the plane as is. So that's what I have been = doing. To recap, my engine is an NA 13B built by Bruce Turrentine. It is a = second gen engine with Turbo rotor housings (no exhaust splitter) and high compression NA rotors. The exhaust uses 1 3/4" x 32" primaries into a = Burns merge collector, 2 1/2" outlet directly into my "muffler". My = "muffler" is essentially a 4 1/2" x 30" tube with some spiral baffles and 2 1/2" inlet/outlet. The intake uses a modified 87 lower manifold casting = port matched to the engine. The upper manifold uses 4 tubes (1 1/2" and 1 = 1/4" dia) over the top of the engine to a small dynamic chamber/plenum = directly over the oil filler port in the center iron housing. The throttle body copies Tracy's original - a stock second gen 3 throat TB cut down to = just 2 ports. The gearbox is Tracy's first RD-1 with 2.17 gears. Prop is a Warnke 68 = x 80 (not sure the pitch number is meaningful - everyone seems to measure = it differently). On the ground static RPM is about 5350 and is reached at = about 2/3 throttle opening. In flight max RPM I've seen is about 5750. The Warnke prop is unique due to the shape. The appearance gets a lot = of comments. I'm really hesitant to mess with it and screw it up = unless/until I can say with certainty that there isnt something else I can do with = tweaking (I'm thinking on the intake side) to improve airflow through the = engine. Hard to believe that there isnt more HP to be had when a hacked 2 = barrel TB is only 2/3 open and I've hit the limit. But like you say there are a = lot of variables. Mike -------------------------------------------------- From: "Ed Anderson" Sent: Monday, February 08, 2010 5:06 AM To: "Rotary motors in aircraft" Subject: [FlyRotary] Throttle limits was Re: N.A. Renesis to turbo > Hi Mike, > > Several things could be causing the situation you see in advancing = your > throttle but getting no increased engine rpm. This is not an = uncommon > situation. Ok assuming we are talking naturally aspired engine (no = forced > induction), fixed pitch prop and assuming your engine is basically = OK (not > weak on compression, etc), > > then the most likely cause is you have simply reach the point at = which > where the engine is producing all the power it can - given the prop = load > it > sees at that moment. Once that point is reached, then advancing the > throttle more does not result in more air flow through the engine = and > therefore no increase in power nor rpm. In fact, it can cause the = engine > to > run leaner and actually produce less power than a partial closed = throttle. > > It's sort of the chicken and the egg in that you need more power to > produce > more rpm, but power is dependent on air flow - which is dependent on = rpm > which dependent on power produced, etc. {:>). But to try to be a = bit more > helpful, look at it this way. > > > Basically for every throttle position (at a constant altitude, temp, = air > density, etc) there is one associated manifold pressure(air = density). > This > manifold pressure is a product of a number of variables, but the = most > dominating ones involving the engine are volumetric efficiency, = throttle > position and engine rpm. Now your volumetric efficiency is more or = less > fixed by the intake/exhaust design so we'll eliminate that for the = moment. > That leaves throttle position and rpm as controllable variables and = your > ambient air density as a fixed (for this discussion). > > > We know the engine is a positive displacement pump which displaces = the > same > volume once each engine cycle. The power the engine produces in that = cycle > is limited by the density of the air in the combustion chamber as = the > volume > is always a constant (fixed by size of your combustion chamber). = The air > density into the combustion chamber is dependent on the air density = in the > intake manifold. > > So that leaves us with: More throttle =3D higher manifold air = density =3D > =3D more oxygen + More fuel(permits more fuel to be burnt) =3D more = power =3D > more rpm. That is until you hit the limit - what limit you say? > > The limit is that once you have opened the throttle plate = sufficiently > that > the air density in the intake manifold is equal to ambient air = density (or > as close as its going to get- given intake losses) - then it will = not make > any difference (in power) to advance the throttle further. Once you = have > reached that limit, then advancing the throttle further does not = further > increase the air density in the manifold and therefore limits the = amount > of > fuel you can burn/power you can make. > > Clearly if you have a large throttle body you can reach that point = with a > smaller opening of the throttle plate than if you have a small = throttle > body. > > As I said - there can be other causes, but this is the one I think = most > folks run into. You can find the same situation even on the ground, = where > again once the manifold air density =3D ambient air density (or as = close as > your engine Ve will permit) you stop producing power increase even = if you > have throttle travel left. > > Therefore if your throttle body is sized so you get max power at = 100% > throttle opening a sea level, then with every increase in altitude, = you > will > find you have additional throttle travel that produces no increase = in > power. > The higher you go in altitude the more throttle travel will be = available > that results in no power increase. This is because the ultimate = limit is > based on the ambient air density. > > Hope this helped. > > Ed > > > > > Ed Anderson > > Rv-6A N494BW Rotary Powered > > Matthews, NC > > eanderson@carolina.rr.com > > http://www.andersonee.com > > http://www.dmack.net/mazda/index.html > > http://www.flyrotary.com/ > > http://members.cox.net/rogersda/rotary/configs.htm#N494BW > > http://www.rotaryaviation.com/Rotorhead%20Truth.htm > > -----Original Message----- > From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On > Behalf Of Mike Wills > Sent: Sunday, February 07, 2010 12:51 PM > To: Rotary motors in aircraft > Subject: [FlyRotary] Re: N.A. Renesis to turbo > > Don, > > I'm at about 23 hours and am seeing roughly the same performance on = my > RV-4 > with a Bruce T built gen 2 13B. My temps are a little cooler. I'm = pretty > happy with the performance, but like you say, its not possible to = have too > much power. But I don't have room for a turbo and intercooler. > > I think there's more power in my NA engine. I'm still a little = mystified > by > the fact that at about 1/2 - 2/3 throttle the engine stops making = any more > power. But I decided to take several people's advice and just fly it = for a > while. I also think there's more speed in it via some drag = reduction. A > turbo would be nice to tame the noise though. > > I'll be interested in seeing how the Burns muffler works out for = you. I'm > not willing to dive into any more muffler experiments for the moment = since > my failed trial with the DNA muffler. But sooner or later, and one = way or > another I have to quiet this thing down. > > Mike Wills > RV-4 N144MW > > -------------------------------------------------- > From: "Don Wallker" > Sent: Saturday, February 06, 2010 6:21 PM > To: "Rotary motors in aircraft" > Subject: [FlyRotary] N.A. Renesis to turbo > >> Dear list, Turbo flyers and especially David Leonard, >> I've 16 flying hours on my RV-8 with a Renesis and all of = Tracy's >> stuff > >> and a Catto 76/88. The airplane flys great, just like an RV, no = gliding >> time, and about 36 hours on the ground. SPECS >> Full throttle 8,000' 174 mph indicated, 2450 on the prop, water = 185, >> oil > >> 205, >> Climb out 110 mph, rate of climb, 1250'/min. Field elevation 5046. >> >> These are not bad numbers, but I would like better. I've been = influenced >> by some of the the local jet jocks who say that there is no such = thing as >> too much horsepower and they are right! N113BR seems to be = performing >> about like a 160-170 HP RV. So I am investigating turboing it! = The idea >> is to have a little better than sea level performance on take off >> (designed for 210HP N.A.) and turbo normalizing at cruise. Up to = 12000' >> would be nice. >> During the air races this year, Dave Leonard showed up and I was = very >> impressed by his airplane. He was able to turbo and inter cool it = and >> have it all inside an RV cowl, so I'll likely base my installation = on >> his. Plus, he has been through the learning curve of 3 or so = turbos so >> he > >> knows what to do, what not to do and what would be better if he = were to >> do > >> it all over again. >> >> I've spent the afternoon looking through the archives, reading as = much as >> I can find about turbos, and downloading all the photos I can. = Here is >> what I am tentatively planning on doing. >> Get one of Techwelding's Renesis exhaust flanges made from 304 SS = and >> have > >> my local waterjet guy copy it and make one out of 321SS. I'll weld = 321 >> SS > >> and manifold it together and run it into the bottom of the turbo = that >> will sit right in front of the exhaust. The turbo will have = additional >> support. Run the turbo outlet air from it through a stock RX-7 = inter >> cooler sitting in front of the left cheek opening and then out to = the >> right side of the engine, probably routing it under the PSRU and = then up >> to a throttle body and manifold. Then four al tubes over the top = of the >> engine into a cut down and welded up stock RX-8 intake manifold. = The >> exhaust out of the turbo will run down and out in the usual center = of the >> back of the cowl opening. I am thinking of trying one of Burns = Stainless >> all SS mufflers. It is basically a glass pack, but instead of = glass, >> they > >> are using stainless steel wool and they say it is holding up for = the >> rotary racers. They make it any length you want and is about 4 lbs = with >> their SS vs 9 lbs with the hushpower 2 I'm using now. The = combustion air >> intake to the turbo will be on the aft left side of the cowl via an = NACA >> duct opening as Dave's is. >> The oil cooler will have to be moved to under the engine. I will = build >> up > >> a fiberglass scoop, probably based on Van's scoop and modify it to = have a >> bigger opening and be farther forward, closer to the prop. I will >> probably have the oil cooler made a little larger (Techwelding) = than the >> one I have now. >> >> That's the basic idea at this point. I'll finalize my plan, = prebuild as >> much as possible before tearing the airplane apart and try for as = little >> down time as possible. I'm looking for the list's critique here, = plus >> questions that I will have missed. The following are a list of = questions >> that I have. >> 1. Which turbo should I use, which orientation and who should I use = to do >> the work, plus what is the approximate price? TO4 hybrid? Dave = and >> Steve Brooks mention BNR turbo as a modifier. Who manufactures the >> turbo? >> 2. What is the ideal situation with a waste gate? Full open or = not, or, >> or? >> 3. I read about a N.O.oil line solenoid to the turbo bearings. I = assume >> that if the Turbo fails, you turn it on to the N.C. position to = prevent >> oil from being pumped down your exhaust? I assume the oil that is = used >> is > >> routed back to the sump. >> 4. What size exhaust is optimum? It seems Dave is running 2.5 = inch. >> 5. What size throttle body should I use and what would be a good = one? >> One > >> throttle body or two? 4. What size injectors should I use, and = where >> should the secondaries be placed? Dave is using 480cc and staging = is at >> 32 inches. Are you using the same for the primaries and is there = an idle >> problem with the larger injectors? >> 5. Anyone out there turboing a Renesis? Anyone flying one? >> 6. My compression is 9.7 to 1. Any problems with this higher >> compression ratio as long as I use an inter cooler and keep the = boost no >> higher than 35"? >> And lot more questions, but that's all I can think of now. >> So If any of you can add any thought, let me know. >> >> Don Walker >> >> -- >> 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 > > __________ Information from ESET NOD32 Antivirus, version of virus > signature > database 3267 (20080714) __________ > > The message was checked by ESET NOD32 Antivirus. > > http://www.eset.com > > > > -- > 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 __________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_00DE_01CAA9C3.20A8A300 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Tracy,
 
I've noted the RPM difference repeatedly so = that I'm=20 sure about.
 
On the MP I have to admit I'm not all that = certain.=20 Pretty sure that once it hits the max power point that there are no = further=20 changes in MP. But I'll have to take a look and make some notes = next=20 flight.
 
Two things make it problematic. I never really = referred=20 to my MP gauge in my previous RV so when I designed my panel and ran out = of=20 space the MP gauge ended up relegated to the center console and is a = little=20 difficult to see in flight. The other problem is that I actually don=92t = have a=20 real MP gauge - I cheaped out and used a good vacuum gauge that I had = laying=20 around. I really need to change both these things.
 
Mike

Sent: Tuesday, February 09, 2010 5:20 AM
Subject: [FlyRotary] Re: rpm vs Power was : Throttle limits = was Re:=20 N.A. Renesis to turbo

Ed's experience pretty much matches my own when changing = gear=20 drive ratios.  A little more top end.  (Sun 100 results were = 209 mph=20 w/ 2.176 drive vs 217.5 mph the next year with 2.85 drive.)   = Takeoff &=20 climb performance improved dramatically though.  It's not an = inexpensive=20 change though.

What does mystify me is the small difference = between=20 Mike's static & top end rpm.  I got an 1100 rpm = difference.  5200=20 vs 6300 with a 68 - 81 Performance prop.

Another detail I'm not = certain=20 about is whether Mike's manifold pressure is or is not increasing during = that=20 last 1/3 - 1/2 throttle travel with no power increase.  Seems like = he said=20 it did go up but I'm not sure.  If it is going up, there is still = something=20 unexplained going on.  What was the MP doing Mike?  Was it at = full=20 ambient at the point where the rpm stopped=20 increasing?

Tracy



On Tue, Feb 9, 2010 at 12:12 AM, Ed Anderson = <eanderson@carolina.rr.com&g= t;=20 wrote:
Well, Mike, just for comparison, when I had a 2.17:1 = and a=20 68 x72
Performance prop, 5200 -5400 rpm on a nominal 70deg day was = what I=20 got for
static.

While I don't claim my set up was the best = in the=20 land, I think it was a
pretty fair set up.  So I would say you = are=20 doing just fine.

It does not matter how large a throttle body = you have=20 when the manifold air
density hits ambient or as close as it can = given any=20 losses in the induction
system - that's it.  You can continue = to open=20 the throttle body, but you
will not get any more power. However, = there is a=20 way!

Looking at some of the variables in the power equation we=20 have:

Power(HP) =3D Torque * rpm/ 5250, swapping some variables = around we=20 get:

RPM =3D Power/torque.  So this indicates the rpm can = increase=20 if either the
power is increased or the torque is decreased. Well, = it's=20 difficult to
increase the power by itself(unless you go to forced = induction=20 or nitrous
oxide)

But one way to get more rpm (and = ultimately more=20 power)  is to lower the
Torque load on the engine. =  Decreasing=20 the Torque permits more engine rpm
even if power did not increase.=20  However we know that more rpm =3D more air =3D
more power. = The torque=20 load on the engine caused by the prop decreases as
your gear ratio=20 increases.


By going to a 2.85:1 gear ratio that would = reduce the=20 load on the engine by
approx 25% (assuming the same prop at the = same static=20 rpm).  Now the rpm
power relationship were linear (which it is = not=20 with a prop as the load)
then I should have gotten around 6650 rpm = with the=20 new gear box - well not
really - due to the cube root relationship = between=20 prop rpm and power, it
will be much less of an increase and due to = the fact=20 I put on a larger
diameter prop.

But in any case, all this = theory=20 aside,  with the 2.85 and 74 x88 prop I now
get engine 6000 - = 6200 rpm=20 static or about an 13% increase in rpm.   So
that's using use = the same=20 intake, throttle body and engine for both.  But
now because = the engine=20 can turn faster (lesser prop load at any specific
rpm).

Now = the fact=20 the engine is turning faster means it takes more airflow = to
maintain the=20 same (ambient) air density in the manifold. This is because = the
higher=20 engine rpm can "suck" that manifold volume (which didn't change)=20 down
faster than it did before.  This in turn means that the = throttle=20 position
has to be more open to let a sufficient increase in air = flow need=20 to achieve
and maintain that (hopefully) ambient air density in the = manifold.

So from what you are reporting, I really don't see = anything=20 poor about your
performance with your set up. In fact, it's pretty=20 good.

The new set up gave a noticeable benefit in take off = performance=20 (and I do
mean noticeable).  However, the top end was = relatively=20 unaffected - although
I did measure an approx 4 mph increase in top = aircraft speed.

In any case, that is my=20 experience.

FWIW

Ed Anderson

Rv-6A N494BW Rotary=20 Powered

Matthews, NC

eanderson@carolina.rr.com
http://www.andersonee.com

http://www.dmack.net/mazda/index.html

http://www.flyrotary.com/

http://members.cox.net/rogersda/rotary/configs.htm#N494BW=

http://www.rotaryaviation.com/Rotorhead%20Truth.htm
-----Original=20 Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]=20 On
Behalf Of Mike Wills
Sent: Monday, February 08, 2010 10:36 = PM
To:=20 Rotary motors in aircraft
Subject: [FlyRotary] Re: Throttle limits = was Re:=20 N.A. Renesis to turbo

Thanks Ed. Mentioned this a few months = ago and=20 was convinced at least for
the moment, to just fly the plane as is. = So=20 that's what I have been doing.

To recap, my engine is an NA 13B = built=20 by Bruce Turrentine. It is a second
gen engine with Turbo rotor = housings=20 (no exhaust splitter) and high
compression NA rotors. The exhaust = uses 1=20 3/4" x 32" primaries into a Burns
merge collector, 2 1/2" outlet = directly=20 into my "muffler". My "muffler" is
essentially a 4 1/2" x 30" tube = with=20 some spiral baffles and 2 1/2"
inlet/outlet. The intake uses a = modified 87=20 lower manifold casting port
matched to the engine. The upper = manifold uses=20 4 tubes (1 1/2" and 1 1/4"
dia) over the top of the engine to a = small=20 dynamic chamber/plenum directly
over the oil filler port in the = center iron=20 housing. The throttle body
copies Tracy's original - a stock second = gen 3=20 throat TB cut down to just 2
ports.

The gearbox is Tracy's = first=20 RD-1 with 2.17 gears. Prop is a Warnke 68 x 80
(not sure the pitch = number=20 is meaningful - everyone seems to measure it
differently). On the = ground=20 static RPM is about 5350 and is reached at about

2/3 throttle = opening.=20 In flight max RPM I've seen is about 5750.

The Warnke prop is = unique=20 due to the shape. The appearance gets a lot of
comments. I'm really = hesitant to mess with it and screw it up unless/until I

can say = with=20 certainty that there isnt something else I can do with = tweaking

(I'm=20 thinking on the intake side) to improve airflow through the=20 engine.

Hard to believe that there isnt more HP to be had when = a hacked=20 2 barrel TB
is only 2/3 open and I've hit the limit. But like you = say there=20 are a lot=20 = of

variables.

Mike

---------------------------------= -----------------
From:=20 "Ed Anderson" <eanderson@carolina.rr.com&g= t;
Sent:=20 Monday, February 08, 2010 5:06 AM
To: "Rotary motors in aircraft" = <flyrotary@lancaironline.net>
Subject:=20 [FlyRotary] Throttle limits was  Re: N.A. Renesis to = turbo

> Hi=20 Mike,
>
> Several things could be causing the situation = you see in=20 advancing your
> throttle but getting no increased engine rpm.=20  This is not an uncommon
> situation. Ok assuming we are = talking=20 naturally aspired engine (no forced
> induction), fixed pitch = prop and=20 assuming your engine is basically OK (not
> weak on compression, = etc),
>
> then the most  likely cause is you have = simply=20 reach the point at which
> where the engine is producing all the = power=20 it can - given the prop load
> it
> sees at that moment.=20  Once that point is reached, then advancing the
> throttle = more=20 does not result in more air flow through the engine and
> = therefore no=20 increase in power nor rpm.  In fact, it can cause the = engine
>=20 to
> run leaner and actually produce less power than a partial = closed=20 throttle.
>
> It's sort of the chicken and the egg in that = you=20 need more power to
> produce
> more rpm, but power is = dependent on=20 air flow - which is dependent on rpm
> which dependent on power=20 produced, etc. {:>).  But to try to be a bit more
> = helpful,=20 look at it this way.
>
>
> Basically for every = throttle=20 position (at a constant altitude, temp, air
> density, etc) = there is one=20 associated manifold pressure(air density).
> This
> = manifold=20 pressure is a product of a number of variables, but the most
>=20 dominating ones involving the engine are volumetric efficiency,=20  throttle
> position and engine rpm.  Now your = volumetric=20 efficiency is more or less
> fixed by the intake/exhaust design = so we'll=20 eliminate that for the moment.
> That leaves throttle position = and rpm=20 as controllable variables and your
> ambient air density as a = fixed (for=20 this discussion).
>
>
> We know the engine is a = positive=20 displacement pump which displaces the
> same
> volume once = each=20 engine cycle. The power the engine produces in that cycle
> is = limited=20 by the density of the air in the combustion chamber as the
>=20 volume
> is always a constant (fixed by size of your combustion=20 chamber).  The air
> density into the combustion chamber is = dependent on the air density in the
> intake = manifold.
>
>=20 So that leaves us with:  More throttle =3D higher manifold air = density=20 =3D
>  =3D more oxygen + More fuel(permits more fuel to be = burnt) =3D=20 more power =3D
> more rpm.  That is until you hit the limit = - what=20 limit you say?
>
> The limit is that once you have opened = the=20 throttle plate sufficiently
> that
> the air density in = the intake=20 manifold is equal to ambient air density (or
> as close as its = going to=20 get- given intake losses) - then it will not make
> any = difference (in=20 power) to advance the throttle further.  Once you have
> = reached=20 that limit, then advancing the throttle further does not = further
>=20 increase the air density in the manifold and therefore limits the=20 amount
> of
> fuel you can burn/power you can=20 make.
>
> Clearly if you have a large throttle body you = can reach=20 that point with a
> smaller opening of the throttle plate than = if you=20 have a small throttle
> body.
>
> As I said - there = can be=20 other causes, but this is the one I think most
> folks run into. = You can=20 find the same situation even on the ground, where
> again once = the=20 manifold air density =3D ambient air density (or as close as
> = your engine=20 Ve will permit) you stop producing power increase even if you
> = have=20 throttle travel left.
>
> Therefore if your throttle body = is sized=20 so you get max power at 100%
> throttle opening a sea level, = then with=20 every increase in altitude, you
> will
> find you have = additional=20 throttle travel that produces no increase in
> power.
> = The higher=20 you go in altitude the more throttle travel will be available
> = that=20 results in no power increase.  This is because the ultimate limit = is
> based on the ambient air density.
>
> Hope this = helped.
>
> Ed
>
>
>
>
> Ed=20 Anderson
>
> Rv-6A N494BW Rotary Powered
>
> = Matthews,=20 NC
>
> eanderson@carolina.rr.com>
>=20 http://www.andersonee.com
>
> http://www.dmack.net/mazda/index.html
>
>= http://www.flyrotary.com/
>
> http://members.cox.net/rogersda/rotary/configs.htm#N494BW=
>
>=20 http://www.rotaryaviation.com/Rotorhead%20Truth.htm>
>=20 -----Original Message-----
> From: Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net]=20 On
> Behalf Of Mike Wills
> Sent: Sunday, February 07, = 2010 12:51=20 PM
> To: Rotary motors in aircraft
> Subject: [FlyRotary] = Re: N.A.=20 Renesis to turbo
>
> Don,
>
> I'm at about 23 = hours=20 and am seeing roughly the same performance on my
> RV-4
> = with a=20 Bruce T built gen 2 13B. My temps are a little cooler. I'm = pretty
>=20 happy with the performance, but like you say, its not possible to have = too
> much power. But I don't have room for a turbo and=20 intercooler.
>
> I think there's more power in my NA = engine. I'm=20 still a little mystified
> by
> the fact that at about 1/2 = - 2/3=20 throttle the engine stops making any more
> power. But I decided = to take=20 several people's advice and just fly it for a
> while. I also = think=20 there's more speed in it via some drag reduction. A
> turbo = would be=20 nice to tame the noise though.
>
> I'll be interested in = seeing=20 how the Burns muffler works out for you. I'm
> not willing to = dive into=20 any more muffler experiments for the moment since
> my failed = trial with=20 the DNA muffler. But sooner or later, and one way or
> another I = have to=20 quiet this thing down.
>
> Mike Wills
> RV-4=20 N144MW
>
>=20 --------------------------------------------------
> From: "Don = Wallker"=20 <drwalker@gbis.com>
> = Sent:=20 Saturday, February 06, 2010 6:21 PM
> To: "Rotary motors in = aircraft"=20 <flyrotary@lancaironline.net>
>=20 Subject: [FlyRotary] N.A. Renesis to turbo
>
>> Dear = list,=20 Turbo flyers and especially David Leonard,
>>   =  I've 16=20 flying hours on my RV-8 with a Renesis and all of Tracy's
>>=20 stuff
>
>> and a Catto 76/88.  The airplane flys = great,=20 just like an RV, no gliding
>> time, and about 36 hours on = the=20 ground. SPECS
>> Full throttle 8,000'   174 mph = indicated, 2450=20 on the prop, water 185,
>> oil
>
>> = 205,
>>=20 Climb out 110 mph, rate of climb, 1250'/min.  Field elevation=20 5046.
>>
>> These are not bad numbers, but I would = like=20 better.  I've been influenced
>> by some of the the = local jet=20 jocks who say that there is no such thing as
>> too much = horsepower=20 and they are right!   N113BR seems to be performing
>> = about=20 like a 160-170 HP RV.  So I am investigating turboing it! =  The=20 idea
>> is to have a little better than sea level performance = on take=20 off
>> (designed for 210HP N.A.) and turbo normalizing at = cruise.=20  Up to 12000'
>> would be nice.
>> During the = air races=20 this year, Dave Leonard showed up and I was very
>> impressed = by his=20 airplane.  He was able to turbo and inter cool it and
>> = have it=20 all inside an RV cowl, so I'll  likely base my installation=20 on
>> his.  Plus, he has been through the learning curve = of 3 or=20 so turbos so
>> he
>
>> knows what to do, what = not to=20 do and what would be better if he were to
>> = do
>
>>=20 it all over again.
>>
>> I've spent the afternoon = looking=20 through the archives, reading as much as
>> I can find about = turbos,=20 and downloading all the photos I can.  Here is
>> what I = am=20 tentatively planning  on doing.
>> Get one of = Techwelding's=20 Renesis exhaust flanges made from 304 SS and
>>=20 have
>
>> my local waterjet guy copy it and make one = out of=20 321SS.  I'll weld 321
>> SS
>
>> and=20  manifold it together and run it into the bottom of the turbo=20 that
>> will sit right in front of the exhaust.  The = turbo will=20 have additional
>> support.  Run the turbo outlet air = from it=20 through a stock RX-7 inter
>> cooler sitting in front of the = left=20 cheek opening and then out to the
>> right side of the = engine,=20 probably routing it under the PSRU and then up
>> to a = throttle body=20 and manifold.  Then four al tubes over the top of the
>> = engine=20 into a cut down and welded up stock RX-8  intake manifold.=20  The
>> exhaust out of the turbo will run down and out = in the=20 usual center of the
>> back of the cowl opening.  I am = thinking=20 of trying one of Burns Stainless
>> all SS mufflers.  It = is=20 basically a glass pack, but instead of glass,
>>=20 they
>
>> are using stainless steel wool and they say = it is=20 holding up for the
>> rotary racers.  They make it any = length=20 you want and is about 4 lbs with
>> their SS vs 9 lbs with = the=20 hushpower 2 I'm using now.  The combustion air
>> intake = to the=20 turbo will be on the aft left side of the cowl via an NACA
>> = duct=20 opening as Dave's is.
>> The oil cooler will have to be moved = to=20 under the engine.  I will build
>> = up
>
>> a=20 fiberglass scoop, probably based on Van's scoop and modify it to have=20 a
>> bigger opening and be farther forward, closer to the = prop.=20  I will
>> probably  have the oil cooler made a = little=20 larger (Techwelding) than the
>> one I have=20 now.
>>
>> That's the basic idea at this point. =  I'll=20 finalize my plan, prebuild as
>> much as possible before = tearing the=20 airplane apart and try for as little
>> down time as = possible.=20  I'm looking for the list's critique here, plus
>> = questions=20 that I will have missed.  The following are a list of=20 questions
>> that I have.
>> 1. Which turbo should I = use,=20 which orientation and who should I use to do
>> the work, = plus what=20 is the approximate price?   TO4 hybrid?  Dave = and
>> Steve=20 Brooks mention BNR turbo as a modifier.  Who manufactures = the
>>=20 turbo?
>> 2. What is the ideal situation with a waste gate?=20  Full open or not, or,
>> or?
>> 3. I read = about a=20 N.O.oil line solenoid to the turbo bearings.  I = assume
>> that=20 if the Turbo fails, you turn it on to the N.C. position to = prevent
>>=20 oil from being pumped down your exhaust?  I assume the oil that = is=20 used
>> is
>
>> routed back to the = sump.
>>=20 4. What size exhaust is optimum?  It seems Dave is running 2.5=20 inch.
>> 5.  What size throttle body should I use and = what would=20 be a good one?
>> One
>
>> throttle body or = two? 4.=20  What size injectors should I use, and where
>> should = the=20 secondaries be placed?   Dave is using 480cc and staging is=20 at
>> 32 inches.  Are you using the same for the = primaries and=20 is there an idle
>> problem with the larger = injectors?
>> 5.=20  Anyone out there turboing a Renesis?  Anyone flying=20 one?
>> 6.  My compression is 9.7 to 1.   Any = problems with=20 this higher
>> compression ratio as long as I use an inter = cooler and=20 keep the boost no
>> higher than 35"?
>> And lot = more=20 questions, but that's all I can think of now.
>> So If any of = you can=20 add any thought, let me know.
>>
>> Don=20 Walker
>>
>> --
>> Homepage:  http://www.flyrotary.com/
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>>
>
>
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