X-Virus-Scanned: clean according to Sophos on Logan.com From: Received: from omr-a013e.mx.aol.com ([204.29.186.60] verified) by logan.com (CommuniGate Pro SMTP 6.1.6) with ESMTPS id 8057732 for flyrotary@lancaironline.net; Thu, 08 Oct 2015 18:54:49 -0400 Received-SPF: pass receiver=logan.com; client-ip=204.29.186.60; envelope-from=ARGOLDMAN@aol.com Received: from mtaomg-aae02.mx.aol.com (mtaomg-aae02.mx.aol.com [172.27.1.100]) by omr-a013e.mx.aol.com (Outbound Mail Relay) with ESMTP id 43BD23800047 for ; Thu, 8 Oct 2015 18:54:14 -0400 (EDT) Received: from core-mxd002c.mail.aol.com (core-mxd002.mail.aol.com [172.29.195.197]) by mtaomg-aae02.mx.aol.com (OMAG/Core Interface) with ESMTP id 1D66638000081 for ; Thu, 8 Oct 2015 18:54:14 -0400 (EDT) Full-name: ARGOLDMAN Message-ID: <36a764.c1b36a2.43484e15@aol.com> Date: Thu, 8 Oct 2015 18:54:14 -0400 Subject: Re: [FlyRotary] Re: To P or not... To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_36a764.c1b36a2.43484e15_boundary" X-Mailer: Unknown sub 13 X-Originating-IP: [50.151.84.32] x-aol-global-disposition: G DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com; s=20150623; t=1444344854; bh=WR6VvvIU9pxoNa3C5rZ+h9DGfedZ1DgrYoSZQ/B8pk8=; h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type; b=578cEN/m86+YVt3DlssikmeguZrW/fuYrz4+3LmkYEO53KyCuU6+50mEkfiSRb35t zPucF5weSk/hozPneiJsXYzOCgEwpsGygvxGRjfaaGy1Xhxbu7EYOiWrvc7RHcoLFk /GbQFdMnsu7ZigcEpfBHsudPwEHC8xJSK/zdkphE= x-aol-sid: 3039ac1b01645616f4166744 --part1_36a764.c1b36a2.43484e15_boundary Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en Turbo controllers can be quite simple or very complex. I had them both. = =20 Ultimately the only thing that controls the amount of turbo is the amount= of =20 exhaust gasses that are shunted through the turbocharger rather than going= =20 out of the exhaust pipe. the more sent to the turbocharger, the more boos= t.=20 The controls of this device (called a waste gate) is where the complexity= =20 and possible danger comes in =20 The simple one is a system that I used in my twin comanche (turbo) where= =20 the turbos were used to make up lost MP as the aircraft ascended. The=20 technique was to use full throttle until the MP started to decrease and= then use=20 two additional throttles (vernier as opposed to the quadrant normal=20 throttles) to increase the MP. =20 The next in degrees ov coplexity is the fixed waste gate which was used= =20 on the early piper senecas. (don't know if it is still being used for them= . =20 In this the waste-gate which normally is variable, is fixed and a specific= =20 amount of exhaust gas is fed through the turbo all the time. The MP is =20 controlled by one throttle. =20 The final system is one that I had on a turbo Viking and it was totally = =20 automatic. The device (electrohydraulic) looked at the MP and other things= and=20 automatically adjusted the wastegate to give the selected pressure. That= =20 was the only thing that had to be reconfigured (in a new aircraft) from= the=20 start. =20 Which ever you choose, there are popoff valves available which limit t he= =20 amount of pressure so not as to overboost the engine. =20 One thing of which to be aware is that when compressing air it heats up = =20 significantly so although you are pumping more air into the cylinders =20 (trochoids) the air is less dense and much hotter. this decreases the =20 effectiveness of a straight turbocharger. =20 Many or most of the modern turbo charged aircraft use intercoolers which= =20 reduce the temp of the inlet charge at the cost of complexity and weight.= =20 =20 Over the past almost 50 years of flying-- if I flew in the mountains a lot= ,=20 I would have a turbo charger. since I am in the midwest, I chose the=20 simpler and more reliable route and am using a NA renesis. =20 Your indutional persuasion may vary. =20 Rich =20 =20 In a message dated 10/8/2015 5:21:02 P.M. Central Daylight Time, =20 flyrotary@lancaironline.net writes: Tom is that a PP 3 rotor? If side port, is it ported in any way? =20 I am not denying all that you say. But 2 rotors are way more readily=20 available and my friend has one already, allegedly basically brand new.= We do=20 need to do some tests on it, but if it is a good motor, I think he will= =20 want to avoid trying to source a 3 rotor or build a PP out of his 2 rotor= . =20 But he thinks he needs more power, hence the turbo option. Question about turbo control for you all. If your goal is very modest=20 boost at sea level, but normalizing at altitude, can you not just use a = boost=20 controller and set a MAP as in manifold absolute pressure and stick to =20 that? Say you set it for 3 psi (roughly 18 psi absolute), that would be= very=20 modest boost at sea level, but at altitude, the turbo would try to stick= to=20 that - maybe it is 6 psi or whatever over atmospheric, but the same =20 absolute pressure. Is there any reason to feel you are stressing the mot= or if you=20 are sticking to reasonable boost like that? =E2=80=94 James On Oct 7, 2015, at 12:33 PM, Tom Mann <_flyrotary@lancaironline.net_=20 (mailto:flyrotary@lancaironline.net) > wrote: =20 =20 =20 Whenever the topic comes up about adding a turbo to a Rotary I go back to= =20 what was the reasoning I used when making the decision to go Rotary in th= e=20 first place. My reasoning was to eliminate as much mechanical complexity as I possibly= =20 could. If I added a turbo then the level of complexity (and weight) went= up. I reasoned that if I needed (or just plain wanted) additional power, I=20 would just add another rotor. That actually gives me more power that the= turbo=20 for where I need it most and the weight comparison is negligible for the= =20 trade-off in power/complexity. =20 I believe that a 2 rotor (using Mistral Engines as a benchmark) produces= =20 190hp N/A (291 lbs) vs. 230hp Turbo (328 lb). The three rotor generates= 300=20 hp @ 375 lb so yes, it=E2=80=99s it=E2=80=99s roughly +50 lbs but +70 hp= as well without a=20 significant increase in complexity. =20 I opted for the 3-rotor solution. Less things to go wrong (which is=20 important to me.) =20 T Mann =20 =3D --part1_36a764.c1b36a2.43484e15_boundary Content-Type: text/html; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Content-Language: en
Turbo controllers can be quite simple or very complex. I had them bot= h.=20 Ultimately the only thing that controls the amount of turbo is the amount= of=20 exhaust gasses that are shunted through the turbocharger rather than going= out=20 of the exhaust pipe. the more sent to the turbocharger, the more boost. Th= e=20 controls of this device (called a waste gate) is where the complexity and= =20 possible danger comes in
 
The simple one is a system that I used in my twin comanche (turbo) wh= ere=20 the turbos were used to make up lost MP as the aircraft ascended. The tech= nique=20 was to use full throttle until the MP started to decrease and then use two= =20 additional throttles (vernier as opposed to the quadrant normal throttles)= to=20 increase the MP.
 
The next in degrees ov coplexity  is the fixed waste gate which= was=20 used on the early piper senecas. (don't know if it is still being used for= them.=20 In this the waste-gate which normally is variable, is fixed and a specific= =20 amount of exhaust gas is fed through the turbo all the time. The MP is=20 controlled by one throttle.
 
The final system is one that I had on a turbo Viking and it was total= ly=20 automatic. The device (electrohydraulic) looked at the MP and other things= and=20 automatically adjusted the wastegate to give the selected pressure. That= was the=20 only thing that had to be reconfigured (in a new aircraft) from the start.=
 
Which ever you choose, there are popoff valves available which limit= t he=20 amount of pressure so not as to overboost the engine.
 
One thing of which to be aware is that when compressing air it heats= up=20 significantly so although you are pumping more air into the cylinders=20 (trochoids) the air is less dense and much hotter. this decreases the=20 effectiveness of a straight turbocharger.
 
 Many or most of the modern turbo charged aircraft use intercool= ers=20 which reduce the temp of the inlet charge at the cost of complexity and=20 weight. 
 
Over the past almost 50 years of flying-- if I flew in the mountains= a lot,=20 I would have a turbo charger. since I am in the midwest, I chose the simpl= er and=20 more reliable route and am using a NA renesis.
 
Your indutional persuasion may vary.
 
Rich
 
In a message dated 10/8/2015 5:21:02 P.M. Central Daylight Time,=20 flyrotary@lancaironline.net writes:
Tom is=20 that a PP 3 rotor?  If side port, is it ported in any way?=20

I am not denying all that you say.  But 2 rotors are way more= =20 readily available and my friend has one already, allegedly basically bra= nd=20 new.  We do need to do some tests on it, but if it is a good motor,= I=20 think he will want to avoid trying to source a 3 rotor or build a PP out= of=20 his 2 rotor.  But he thinks he needs more power, hence the turbo=20 option.

Question about turbo control for you all.  If your goal is ver= y=20 modest boost at sea level, but normalizing at altitude, can you not just= use a=20 boost controller and set a MAP as in manifold absolute pressure and stic= k to=20 that?  Say you set it for 3 psi (roughly 18 psi absolute), that wou= ld be=20 very modest boost at sea level, but at altitude, the turbo would try to= stick=20 to that - maybe it is 6 psi or whatever over atmospheric, but the same= =20 absolute pressure.  Is there any reason to feel you are stressing= the=20 motor if you are sticking to reasonable boost like that?

=E2=80=94 James

On Oct 7, 2015, at 12:33 PM, Tom Mann <flyrotary@lancaironline.ne= t>=20 wrote:

Whenever the topic comes up about ad= ding a=20 turbo to a Rotary I go back to what was the reasoning I used when maki= ng the=20 decision to go Rotary in the first place.
My reasoning was to eliminate as muc= h=20 mechanical complexity as I possibly could. If I added a turbo then the= level=20 of complexity (and weight) went up.
I reasoned that if I needed (or just= plain=20 wanted) additional power, I would just add another rotor. That actuall= y=20 gives me more power that the turbo for where I need it most and the we= ight=20 comparison is negligible for the trade-off in power/complexity.=
 
I believe that a 2 rotor (using Mist= ral=20 Engines as a benchmark) produces 190hp N/A (291 lbs) vs. 230hp Turbo= (328=20 lb). The three rotor generates 300 hp @ 375 lb so yes, it=E2=80=99s it= =E2=80=99s roughly +50=20 lbs but +70 hp as well without a significant increase in complexity.= =20
 
I opted for the 3-rotor solution. Le= ss things=20 to go wrong (which is important to me.)
 
T Mann
 

=3D
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