X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from rv-out-0506.google.com ([209.85.198.239] verified) by logan.com (CommuniGate Pro SMTP 5.2.10) with ESMTP id 3287712 for flyrotary@lancaironline.net; Wed, 12 Nov 2008 14:34:19 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.198.239; envelope-from=rwstracy@gmail.com Received: by rv-out-0506.google.com with SMTP id f6so589483rvb.7 for ; Wed, 12 Nov 2008 11:33:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:sender :to:subject:in-reply-to:mime-version:content-type:references :x-google-sender-auth; bh=yUfPUeVKNVRnoRd2XH1H5XUMtxTk3v5FqWVPOL94jbY=; b=AWIBbQ4EIlk0rFE6ilQF0XfpyTmLrlKWjtoO8TiAVYQMZ9suvDbbIJBHrhhoj2ZuZX wWmnNj9UCATpSfoh9Ej2Dwza8XEdjd02V7WMpFGgpzDFX1+IZDV5TyAUcqGuenGL8zOS 70u+SspGK7snj1pgnbYAzXcaNiJLQwmVyK+yo= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:in-reply-to:mime-version :content-type:references:x-google-sender-auth; b=gf+YdgtohzsJMN/mpcCWU9O4VqTyJ1ufS+IumDQglSgrp+6zyPkBigszk2QNUiHF/u ISNctSaKSQwSi/MsA3tdSbHP5JMRe+jPYEQGx6wlVXlQG/5p0QsHJEg2B0YrdcHJOXMo ZIp8ksfYXJxVDYimpXepr35Zl2oPu02ycYTg8= Received: by 10.141.88.3 with SMTP id q3mr5048143rvl.226.1226518421494; Wed, 12 Nov 2008 11:33:41 -0800 (PST) Received: by 10.141.133.12 with HTTP; Wed, 12 Nov 2008 11:33:41 -0800 (PST) Message-ID: <1b4b137c0811121133h554a5011sc5ff84186f4c5b2d@mail.gmail.com> Date: Wed, 12 Nov 2008 14:33:41 -0500 From: "Tracy Crook" Sender: rwstracy@gmail.com To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] IVO Props, etc. In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_11530_25403949.1226518421479" References: X-Google-Sender-Auth: 844205825a28d363 ------=_Part_11530_25403949.1226518421479 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Just reading the TAS number (181 Kts) it doesn't look bad. The trouble is in the other numbers. Let's take a closer look. 17,000 ft . You always get more airspeed per pound of thrust at higher altitude. Only reason most people don't quote TAS at this altitude is that the engine looses power (lower thrust) at altitude. This was not the case in this test since the engine was turbocharged and boosted to ABOVE ambient at sea lever (34"). The airplane SHOULD have been hauling ass under this condition. No fuel burn number was given but that would have been interesting. This isn't a perfect example but for rough comparison purposes, my RV-4 averaged (from a dead stop) 189 Kts at sea level with just a bit over 30" manifold pressure. If you corrected that for altitude at 17,000 feet, that would be well over 220 Kts. (don't have my E6B handy to do the actual calculation). The only way to do a real comparison is to put a different prop on the same plane and fly it under the same conditions. Tracy Crook On Wed, Nov 12, 2008 at 1:48 PM, Kelly Troyer wrote: > Doug, > Did Ross state his "IVO" diameter and if 2 or 3 blades > !!............... > -- > Kelly Troyer > "Dyke Delta"_13B ROTARY Engine > "RWS"_RD1C/EC2/EM2 > "Mistral"_Backplate/Oil Manifold > > > > > > -------------- Original message from DLOMHEIM@aol.com: -------------- > > Ross Farnham, who posts in the Van's Airforce "alternative engine" forum > (and who if he wasn't a Subie guy would most likely be a regular on this > list); has done quite a bit of testing with the IVO Magnum "high pitch" > version on his RV-6A, turbo Subie. The best "top speed" (for what that's > worth in this day and age) I could find in his data was at a DA of 17,000 > ft. and " 34 inches 5000 rpm, mixture -10%, 181 knots TAS". That really > isn't too bad for the price you pay for an IVO in my opinion. See this link > for his IVO testing information: http://www.sdsefi.com/rv13.htm > > His web pages also fully document the many cooling modifications he > went through with his installation until it finally was "right", much like > those who have gone before on this list have had to do. This also is well > documented and makes for interesting reading if you haven't checked out his > site before. http://www.sdsefi.com/rv12.htm > > I plan on using an IVO on my RV-9A installation since it appears from > Ross's data that it should provide more than adequate climb performance and > will also cruise well in the 150-160 mph range (where I plan on spending > most of my time). An MT would be nice, but the cost is prohibitive on my > budget. Here is a summary of Ross's IVO conclusions from his web page: > > 07/21/04 > > At the 90 hour engine/prop time mark we have some more observations on the > IVO Magnum: > > 1. We have had no issues with bolts or blades coming loose. > > 2. The in-flight adjustment works well. We use a 0-20 amp ammeter to judge > blade position. > > 3. After the first set of brushes laid down carbon on the slip rings, brush > life now exceeds 30 hours between changes > > 4. Despite having *too low a reduction ratio for our airframe*, the Magnum > offers good takeoff and climb performance. *Medium speed cruise > performance is comparable to other certified aircraft propellers*. High > speed performance also seems comparable although we'd like to have a lower > reduction ratio to turn the prop faster and absorb more hp. > > 5. Given the speed vs. fuel flow considerations on our turbocharged RV6A, > this prop is matched well and is a viable alternative to expensive constant > speed, certified propellers. A fixed pitch prop on the turbocharged engine > would degrade performance considerably, especially in the takeoff, climb and > high altitude cruise regimes. > > 6. A slight vibration is set up if the propeller is coarsed out too much > for the flight speed, likely due to the blade being partially stalled. > > 7. Ambient temperature and altitude (density altitude) affect pitch angles > required for a given hp and rpm. > > For takeoff using 38 inches MAP, 4800 engine rpm/ 2182 prop rpm we set > pitch at 3 amps fine of neutral pitch. This is at a hp of around 170, prop > torque is 409 ft./lbs. Density altitude 3500-4500 MSL. > > For climb at 35 inches MAP, 4500-4800 engine rpm/ 2045-2182 prop rpm we set > pitch at 2 amps fine to neutral. This is at an IAS of 80-95 knots. Hp is > 150-155, torque at prop is about 374 ft./lbs. Density altitude around 6000 > MSL. > > For cruise at 30 inches MAP, 4200 engine rpm/ 1909 prop rpm we set pitch at > 13 amps coarse. This is at an IAS of 130 knots. HP is around 114, torque at > prop about 314 ft./lbs. Density altitude 11,000 MSL. > > We don't run the pitch past 15 amps coarse and figure that this results in > a pitch of 95 to 100 inches. > > (note: italics are mine...) > > > > Doug Lomheim > > RV-9A; 13B/ FWF > > > > > > ------------------------------ > Get the Moviefone Toolbar. > Showtimes, theaters, movie news & more! > > ------=_Part_11530_25403949.1226518421479 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline  Just reading the TAS number (181 Kts) it doesn't look bad.   The trouble is in the other numbers.  Let's take a closer look.   17,000 ft .  You always get more airspeed per pound of thrust at higher altitude.   Only reason most people don't quote TAS at this altitude is that the engine looses power (lower thrust) at  altitude.  This was not the case in this test since the engine was turbocharged and boosted to ABOVE ambient at sea lever (34").  The airplane SHOULD have been hauling ass under this condition.  No fuel burn number was given but that would have been interesting.

This isn't a perfect example but for rough comparison purposes, my RV-4 averaged (from a dead stop)  189 Kts at sea level with just a bit over 30" manifold pressure.  If you corrected that for altitude at 17,000 feet, that would be well over 220 Kts. (don't have my E6B handy to do the actual calculation).

The only way to do a real comparison is to put a different prop on the same plane and fly it under the same conditions.

Tracy Crook



     

On Wed, Nov 12, 2008 at 1:48 PM, Kelly Troyer <keltro@att.net> wrote:
Doug,
   Did Ross state his "IVO" diameter and if 2 or 3 blades !!............... 
--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold



 
-------------- Original message from DLOMHEIM@aol.com: --------------

Ross Farnham, who posts in the Van's Airforce "alternative engine" forum (and who if he wasn't a Subie guy would most likely be a regular on this list); has done quite a bit of testing with the IVO Magnum "high pitch" version on his RV-6A, turbo Subie.  The best "top speed" (for what that's worth in this day and age) I could find in his data was at a DA of 17,000 ft. and " 34 inches 5000 rpm, mixture -10%, 181 knots TAS".  That really isn't too bad for the price you pay for an IVO in my opinion.  See this link for his IVO testing information:  http://www.sdsefi.com/rv13.htm
 
His web pages also fully document the many cooling modifications he went through with his installation until it finally was "right", much like those who have gone before on this list have had to do.  This also is well documented and makes for interesting reading if you haven't checked out his site before.   http://www.sdsefi.com/rv12.htm
 
I plan on using an IVO on my RV-9A installation since it appears from Ross's data that it should provide more than adequate climb performance and will also cruise well in the 150-160 mph range (where I plan on spending most of my time).  An MT would be nice, but the cost is prohibitive on my budget.  Here is a summary of Ross's IVO conclusions from his web page:
 
07/21/04

At the 90 hour engine/prop time mark we have some more observations on the IVO Magnum:

1. We have had no issues with bolts or blades coming loose.

2. The in-flight adjustment works well. We use a 0-20 amp ammeter to judge blade position.

3. After the first set of brushes laid down carbon on the slip rings, brush life now exceeds 30 hours between changes

4. Despite having too low a reduction ratio for our airframe, the Magnum offers good takeoff and climb performance. Medium speed cruise performance is comparable to other certified aircraft propellers. High speed performance also seems comparable although we'd like to have a lower reduction ratio to turn the prop faster and absorb more hp.

5. Given the speed vs. fuel flow considerations on our turbocharged RV6A, this prop is matched well and is a viable alternative to expensive constant speed, certified propellers. A fixed pitch prop on the turbocharged engine would degrade performance considerably, especially in the takeoff, climb and high altitude cruise regimes.

6. A slight vibration is set up if the propeller is coarsed out too much for the flight speed, likely due to the blade being partially stalled.

7. Ambient temperature and altitude (density altitude) affect pitch angles required for a given hp and rpm.

For takeoff using 38 inches MAP, 4800 engine rpm/ 2182 prop rpm we set pitch at 3 amps fine of neutral pitch. This is at a hp of around 170, prop torque is 409 ft./lbs. Density altitude 3500-4500 MSL.

For climb at 35 inches MAP, 4500-4800 engine rpm/ 2045-2182 prop rpm we set pitch at 2 amps fine to neutral. This is at an IAS of 80-95 knots. Hp is 150-155, torque at prop is about 374 ft./lbs. Density altitude around 6000 MSL.

For cruise at 30 inches MAP, 4200 engine rpm/ 1909 prop rpm we set pitch at 13 amps coarse. This is at an IAS of 130 knots. HP is around 114, torque at prop about 314 ft./lbs. Density altitude 11,000 MSL.

We don't run the pitch past 15 amps coarse and figure that this results in a pitch of 95 to 100 inches.

(note:  italics are mine...)

 

Doug Lomheim

RV-9A; 13B/ FWF

 




Get the Moviefone Toolbar. Showtimes, theaters, movie news & more!

------=_Part_11530_25403949.1226518421479--