X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [201.225.225.167] (HELO cwpanama.net) by logan.com (CommuniGate Pro SMTP 5.1c.4) with ESMTP id 1407524 for flyrotary@lancaironline.net; Sun, 17 Sep 2006 21:55:08 -0400 Received-SPF: none receiver=logan.com; client-ip=201.225.225.167; envelope-from=rijakits@cwpanama.net Received: from [201.224.93.110] (HELO usuario5ebe209) by frontend1.cwpanama.net (CommuniGate Pro SMTP 4.2.10) with SMTP id 79076082 for flyrotary@lancaironline.net; Sun, 17 Sep 2006 21:32:32 -0500 Message-ID: <003301c6dac5$5897e580$6e5de0c9@usuario5ebe209> From: "Thomas y Reina Jakits" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: ducted fan questions Date: Sun, 17 Sep 2006 20:54:15 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0030_01C6DA9B.6F8D6000" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2869 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.2962 This is a multi-part message in MIME format. ------=_NextPart_000_0030_01C6DA9B.6F8D6000 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable MessageRusty, the shortest way to all the know-how is via Perry Mick's webpage! http://www.bridgingworlds.com/DUCKT.HTM A motherload of info! Lots of links too, e.g.: http://massflow.archivale.com/ductbook.htm Best is to contact him - this will put you a lightyear or two ahead of = the game, so you can continue where everyone else gets tired of ducts! = :)) A gyro would be a good application, as there are only two speed-regimes: acceleration to flight speed, flightspeed, decceleration to land. The gyros generally available for the ultralight/experimental market do = not have a collective control. So there is only one trimmed speed/rpm. You want to go faster - you climb; Go slower - you sink. To my knowledge there are only 2 gyros with a full collective control - = Air&Space 2 seater and the Groen (brothers) Hawk. Both are certified expensive machines.... I am thinking of some way to incorporate a collective control with the = rather simple head design of the experimental gyros - something like a = Robinson helicopters tailrotor pitch change mechanism.... It would allow to change your speed/rpm trim and it would allow = jump-take offs - pre-rotate the rotor to about 150% nominal cruise rpm - = disengage pre-rotator - raise collective to cruise position (or even = higher) - vertical take-off - inertia keeps the rotor running, but = slowing down - at about 50ft apply throttle and go flying (adjust = collective for cruise rpm). The other way around for landing! The only thing you could not do is = hovering, like a helo! Thomas J. ----- Original Message -----=20 From: Russell Duffy=20 To: Rotary motors in aircraft=20 Sent: Sunday, September 17, 2006 8:12 PM Subject: [FlyRotary] Re: ducted fan questions All the GenAv duct attempts I could dig up wound up ditching the duct and going back to a prop, some after significant time and expense. Hi Donald, Thanks for the comments. I've also noticed an huge lack of examples = of GA ducted fans, and that usually tells you something important :-) =20 I've been led to believe that ducted fans had some thrust advantages = at low airspeeds, but that they generally wouldn't work well at normal = GA type cruise speeds. Since a gyrocopter is a slow aircraft, that = lives for thrust, it just seems like it would possible work. On the = other hand, it's probably worth noting that there aren't any fan units = out there for Rotax engines on gyros, or pusher ultralights for that = matter. =20 Cheers, Rusty =20 ------=_NextPart_000_0030_01C6DA9B.6F8D6000 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Message
Rusty,
 
the shortest way to all the know-how is = via Perry=20 Mick's webpage!
http://www.bridgingworld= s.com/DUCKT.HTM
A motherload of info!
Lots of links too, e.g.: http://massflow.archi= vale.com/ductbook.htm
 
Best is to contact him - this will = put you a=20 lightyear or two ahead of the game, so you can continue where everyone = else gets=20 tired of ducts! :))
 
A gyro would be a good application, as = there are=20 only two speed-regimes:
acceleration to flight speed, = flightspeed,=20 decceleration to land.
The gyros generally available for the=20 ultralight/experimental market do not have a collective control. So = there is=20 only one trimmed speed/rpm.
You want to go faster - you climb; Go = slower =20 - you sink.
To my knowledge there are only 2 gyros = with a full=20 collective control - Air&Space 2 seater and the Groen (brothers)=20 Hawk.
Both are certified expensive=20 machines....
 
I am thinking of some way to = incorporate a=20 collective control with the rather simple head design of the = experimental gyros=20 - something like a Robinson helicopters tailrotor pitch change=20 mechanism....
It would allow to change your speed/rpm = trim and it=20 would allow jump-take offs - pre-rotate the rotor to about 150% = nominal=20 cruise rpm - disengage pre-rotator - raise collective to cruise position = (or=20 even higher) - vertical take-off - inertia keeps the rotor running, but = slowing=20 down - at about 50ft apply throttle and go flying (adjust collective for = cruise=20 rpm).
The other way around for landing! The = only thing=20 you could not do is hovering, like a helo!
 
Thomas J.
----- Original Message -----
From:=20 Russell=20 Duffy
Sent: Sunday, September 17, = 2006 8:12=20 PM
Subject: [FlyRotary] Re: ducted = fan=20 questions

All the GenAv duct attempts I could dig
up wound = up=20 ditching the duct and going back to a prop, some after
significant = time and=20 expense.

 
Hi=20 Donald,
 
Thanks = for the=20 comments.  I've also noticed an huge lack of examples of GA = ducted fans,=20 and that usually tells you something important :-)  =
 
I've = been led to=20 believe that ducted fans had some thrust advantages at=20 low airspeeds, but that they generally wouldn't work well at = normal GA=20 type cruise speeds.  Since a gyrocopter is a slow aircraft, that = lives=20 for thrust, it just seems like it would possible work.  On the = other=20 hand, it's probably worth noting that there aren't any fan units out = there for=20 Rotax engines on gyros, or pusher ultralights for that=20 matter.  
 
Cheers,
Rusty
  =



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