X-Virus-Scanned: clean according to Sophos on Logan.com From: "Bill Bradburry" Received: from vms173023pub.verizon.net ([206.46.173.23] verified) by logan.com (CommuniGate Pro SMTP 6.1.2) with ESMTPS id 7694154 for flyrotary@lancaironline.net; Fri, 15 May 2015 15:04:36 -0400 Received-SPF: pass receiver=logan.com; client-ip=206.46.173.23; envelope-from=bbradburry@verizon.net Received: from Desktop ([71.164.185.6]) by vms173023.mailsrvcs.net (Oracle Communications Messaging Server 7.0.5.32.0 64bit (built Jul 16 2014)) with ESMTPA id <0NOE001GSNMJJ9X0@vms173023.mailsrvcs.net> for flyrotary@lancaironline.net; Fri, 15 May 2015 14:04:01 -0500 (CDT) X-CMAE-Score: 0 X-CMAE-Analysis: v=2.1 cv=B/MOC1ok c=1 sm=1 tr=0 a=20weQFHSdBTlwctzPCQ/Gw==:117 a=kUPQlYmSbg0A:10 a=o1OHuDzbAAAA:8 a=oR5dmqMzAAAA:8 a=-9mUelKeXuEA:10 a=h1PgugrvaO0A:10 a=r77TgQKjGQsHNAKrUKIA:9 a=9iDbn-4jx3cA:10 a=cKsnjEOsciEA:10 a=gZbpxnkM3yUA:10 a=Ia-xEzejAAAA:8 a=JrymXXJqk3-d01SEVTsA:9 a=kHLUWuSAmO0kiBle:21 a=I-_-h-eitt6RjoBR:21 a=CjuIK1q_8ugA:10 a=SSmOFEACAAAA:8 a=QvR66TabWR9rLXrrGbYA:9 a=gKITeKqfq2iKQLOk:21 a=DPIlRJ6Yp4uzFqto:21 a=zBbAPdDI91cfesC3:21 a=gKO2Hq4RSVkA:10 a=UiCQ7L4-1S4A:10 a=hTZeC7Yk6K0A:10 a=frz4AuCg-hUA:10 To: "'Rotary motors in aircraft'" References: In-reply-to: Subject: RE: [FlyRotary] Re: Return to Flight - 2 Date: Fri, 15 May 2015 14:03:57 -0500 Message-id: MIME-version: 1.0 Content-type: multipart/alternative; boundary="----=_NextPart_000_001F_01D08F17.FF9355D0" X-Mailer: Microsoft Office Outlook 11 Thread-index: AdCPPETeWCVjVQx/QHugKhE9WticJQABRiIA X-MIMEOLE: Produced By Microsoft MimeOLE V6.0.6002.18463 This is a multi-part message in MIME format. ------=_NextPart_000_001F_01D08F17.FF9355D0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit I am doing the same with my Renesis, except I have not found the energy to install an adjustable cowl flap. I just install an open cowl flap for summer flying and block it off for winter flying. :>) I somehow seem to gain about 3 knots in the winter... Bill _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] Sent: Friday, May 15, 2015 1:23 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Return to Flight - 2 Jeff, Number 2 did the trick on my 3-rotor installation. I open it on taxi and climb, and then close it for minimal drag in cruise. Btw, I'm using an adjustable cowl flap. Mark Sent from my iPad On May 15, 2015, at 10:19 AM, Jeff Whaley wrote: Well, the second flight occurred last night with same results as before; one short low-level circuit due to insufficient cooling . looks like Al Wick made the correct prediction. There are 3 things I can try with the current configuration: 1) Increase inlet area 2) Increase outlet area (adjustable cowl flap) 3) Re-profile the pinched diffuser. I will do all 3 and see what happens. If all of the above show remarkable improvement then repositioning the radiator is the only alternative. Jeff From: Bobby J. Hughes [mailto:flyrotary@lancaironline.net] Sent: Wednesday, May 06, 2015 12:36 PM Subject: RE: [FlyRotary] Re: Return to Flight Al, "Sorry to say, the pressure you see has no significant effect on cooling efficiency (heat transfer). The next time you fly, since you've removed most of that air, you will still see 210F. Just like before". If the air was trapped at the top of the heat exchanger I would expect improved temperatures. Could be wrong. Bobby Hughes From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] Sent: Wednesday, May 06, 2015 11:15 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Return to Flight Hi Jeff. I've done lot's of experimenting with cooling sys. Tough to explain all this, but I'll give it a try: Pretty clear you saw 6 psi only because you took off with 3+ cups of air in the system. If you'd taken off with 2 cups of air, then pressure would have been 9 psi. 1 cup, 14 psi. No air in system, then you would have seen rated cap pressure (16 psi in your case). Sorry to say, the pressure you see has no significant effect on cooling efficiency (heat transfer). The next time you fly, since you've removed most of that air, you will still see 210F. Just like before. There's one huge exception to that statement, that's if you have air in sys that can't move to a high point out of the flow. In that case air in sys has huge negative effect. Causes local boiling when it passes hot areas and inflates cooling temp. You don't have to fly to prove these concepts. Ground running at idle is all that's needed. Let's assume all air is removed. Then letting engine warm up to 180 F will result in rapid pressure rise to 16 psi (rated cap pressure). Fluid will exit system. With 2 cups of air in sys, that same 180F will yield slow rise in pressure to only 9 psi. No fluid will leave sys. A good cooling design pretends air is stuck in block, so you add a path for that air to rise out of the block coolant flow. This is called a dynamic bleed. Air is automatically removed from engine coolant flow. Super low risk way to fly as you no longer care if air is in system. It's can't affect cooling. It's a bit higher risk to fly without dynamic air bleed, you just make darn sure you purge all air from block sys prior to flight. Applying vacuum to rad cap is great way to remove air. One of the ironies about cooling design is that air that resides above engine flow is a safety asset. For example, your cap is highest point in sys and you have 2 cups of air under cap. Big safety advantage simply because your pressure gage is then a great predictor of how well your sys is doing. A leak will be detected long before overheating. A bunch of other assets to this design. Conversely, air in engine flow has overwhelming negative affect. Temps soar and risks boil over. Clear as mud eh? Fwiw -al wick This message, and the documents attached hereto, is intended only for the addressee and may contain privileged or confidential information. Any unauthorized disclosure is strictly prohibited. If you have received this message in error, please notify us immediately so that we may correct our internal records. Please then delete the original message. Thank you. ------=_NextPart_000_001F_01D08F17.FF9355D0 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

I am doing the same with my = Renesis, except I have not found the energy to install an adjustable cowl = flap.  I just install an open cowl flap for summer flying and block it off for winter flying.  :>)

 

I somehow seem to gain about 3 = knots in the winter…..

 

Bill

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net]
Sent: Friday, May 15, = 2015 1:23 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Return to Flight - 2

 

Jeff,

 

Number 2 did the trick on my 3-rotor installation. I open it on = taxi and climb, and then close it for minimal drag in cruise. Btw, I'm using = an adjustable cowl flap. 

 

Mark



Sent from my iPad


On May 15, 2015, at 10:19 AM, Jeff Whaley <flyrotary@lancaironline.net> wrote:

Well, the = second flight occurred last night with same results as before; one short = low-level circuit due to insufficient cooling … looks like Al Wick made the = correct prediction.

There are 3 = things I can try with the current configuration: 1) Increase inlet area 2) = Increase outlet area (adjustable cowl flap) 3) Re-profile the pinched = diffuser.  I will do all 3 and see what = happens.

If all of = the above show remarkable improvement then repositioning the radiator is the only alternative.

Jeff

 =

From: Bobby = J. Hughes [mailto:flyrotary@lancaironlin= e.net]
Sent: Wednesday, May 06, = 2015 12:36 PM
Subject: RE: [FlyRotary] = Re: Return to Flight

 

Al,

 =

“Sorry = to say, the pressure you see has no significant effect on cooling efficiency (heat transfer). The next time you fly, since you’ve removed most of = that air, you will still see 210F. Just like = before”.

 

If the air = was trapped at the top of the heat exchanger I would expect improved temperatures. = Could be wrong.

 

Bobby = Hughes

 =

 =

 =

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironlin= e.net]
Sent: Wednesday, May 06, = 2015 11:15 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Return to Flight

 

Hi Jeff. = I’ve done lot’s of experimenting with cooling sys. Tough to explain all = this, but I’ll give it a try:

Pretty clear = you saw 6 psi only because you took off with 3+ cups of air in the system. If = you’d taken off with 2 cups of air, then pressure would have been 9 psi. 1 cup, 14 = psi. No air in system, then you would have seen rated cap pressure (16 psi in = your case).

 

Sorry to say, = the pressure you see has no significant effect on cooling efficiency (heat transfer). The next time you fly, since you’ve removed most of = that air, you will still see 210F. Just like before. There’s one huge exception = to that statement, that’s if you have air in sys that can’t move to = a high point out of the flow. In that = case air in sys has huge negative effect. Causes local boiling when it passes hot = areas and inflates cooling temp.

 

You = don’t have to fly to prove these concepts. Ground running at idle is all that’s = needed. Let’s assume all air is removed. Then letting engine warm up to 180 F will = result in rapid pressure rise to 16 psi (rated cap pressure). Fluid will exit = system. With 2 cups of air in sys, that same 180F will yield slow rise in pressure to = only 9 psi. No fluid will leave sys.

 

A good = cooling design pretends air is stuck in block, so you add a path for that air to rise = out of the block coolant flow. This is called a dynamic bleed. Air is = automatically removed from engine coolant flow. Super low risk way to fly as you no = longer care if air is in system. It’s can’t affect cooling. =

 

It’s a = bit higher risk to fly without dynamic air bleed, you just make darn sure you purge all = air from block sys prior to flight. Applying vacuum to rad cap is great way = to remove air.

 

One of the = ironies about cooling design is that air that resides above engine flow is a = safety asset. For example, your cap is highest point in sys and you have 2 cups = of air under cap. Big safety advantage simply because your pressure gage is = then a great predictor of how well your sys is doing. A leak will be detected = long before overheating. A bunch of other assets to this design. =

 

Conversely, = air in engine flow has overwhelming negative affect. Temps soar and risks boil over. =

 

Clear as mud = eh?

 

Fwiw

 

-al = wick

 

This message, and the documents attached hereto, is intended = only for the addressee and may contain privileged or confidential information. = Any unauthorized disclosure is strictly prohibited. If you have received = this message in error, please notify us immediately so that we may correct = our internal records. Please then delete the original message. Thank you. =

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