---------------------------------------------------------- TeamGrumman-List Digest Archive --- Total Messages Posted Tue 09/19/06: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 07:03 AM - Re: lower cowling (flyv35b) 2. 08:15 AM - PowerFLow (923te) 3. 11:28 AM - Re: lower cowling (teamgrumman@AOL.COM) 4. 03:40 PM - Re: PowerFLow (FLYaDIVE@AOL.COM) ________________________________ Message 1 _____________________________________ Time: 07:03:25 AM PST US From: "flyv35b" Subject: Re: TeamGrumman-List: lower cowling Gary's right about the 78/79 models cracking. But maybe it is due to the cowling flexing more due to the hole being cutout for the exhaust tailpipe rather than the exhaust pulses. Whatever it is the stresses are more concentrated at the front corner of the air outlet "box" than they are with the fiberglass outlets used on the earlier models. And maybe just patching the hole with an aluminum or composite filler patch (with the PF internal design) will stiffen the cowl and make it better. The PF might be better (who knows) but it does require cutting out quite a bit of material from the outlet duct for the tailpipe and this could change things as well. You could always install Gary's outlet ducts. It's not that big a deal to make a nice looking patch with flush rivets. Most repairs I have seen have be lazy with AN470 rivets in a haphazard pattern, or worse, pop or avex rivets. Cliff ----- Original Message ----- From: Gil Alexander To: teamgrumman-list@matronics.com Sent: Monday, September 18, 2006 10:18 PM Subject: Re: TeamGrumman-List: lower cowling At 12:19 PM 9/18/2006, you wrote: --> TeamGrumman-List message posted by: teamgrumman@aol.com Unfortunately, no. You're stuck with a patch. All 78 and 79 Tiger cowlings will crack on the lower right side in the cooling exit ramp area. The metal cooling exit ramps do not absorb enough of the vibrations from the prop-exhaust pulses. The only way I know of to recuce or eliminate future cracks is to replace the metal ramp with a fiberglass ramp. Gary... is the damage less with a PowerFlow exhaust?? The pulses should not be hitting the cowling... gil A -----Original Message----- From: tiger862@ligtel.com To: teamgrumman-list@matronics.com Sent: Mon, 18 Sep 2006 9:37 AM Subject: TeamGrumman-List: lower cowling Is there anyway to repair cracks in a lower cowling on a 1978 Tiger, besides putting patches on the outside? ________________________________ Message 2 _____________________________________ Time: 08:15:54 AM PST US From: "923te" <923te@cox.net> Subject: TeamGrumman-List: PowerFLow Since Powerflow has been brought up again I thought I would comment. I am quite curious how PowerFlow got thru the STC process seeemingly so easily.... Compared to what trouble the FAA is giving Gary with a far better cowl than available anywhere for our grummans. I guess once you have worked with the FAA for several years and acheived several STC's they cut you some slack I am suspicious that the short stack approval process did not check out a lot of things....like the effects to air flow and cooling by interrupting the exit ramp flow or the additional heat gain inside the cowl which I think has shortened a few owners battery life. Things I wish were addressed now that I bought into the short stack. Just venting and hoping Gary's cowl gets approved soon...hang in there Gary and don't let those FAA weenies stop you. Regards, Ned ________________________________ Message 3 _____________________________________ Time: 11:28:38 AM PST US Subject: Re: TeamGrumman-List: lower cowling From: teamgrumman@AOL.COM --> TeamGrumman-List message posted by: teamgrumman@aol.com Well, now, that is a great question. I guess once the planes have been is service with repairs AND a short stack powerflow for a long enough time to see if the repairs crack. Gary -----Original Message----- From: gilalex@earthlink.net Sent: Mon, 18 Sep 2006 10:18 PM Subject: Re: TeamGrumman-List: lower cowling Gary... is the damage less with a PowerFlow exhaust?? The pulses should not be hitting the cowling... gil A -----Original Message----- From: tiger862@ligtel.com To: teamgrumman-list@matronics.com Sent: Mon, 18 Sep 2006 9:37 AM Subject: TeamGrumman-List: lower cowling Is there anyway to repair cracks in a lower cowling on a 1978 Tiger, besides putting patches on the outside? ________________________________________________________________________ Check out the new AOL. Most comprehensive set of free safety and security tools, free access to millions of high-quality videos from across the web, free AOL Mail and more. ________________________________ Message 4 _____________________________________ Time: 03:40:41 PM PST US From: FLYaDIVE@AOL.COM Subject: Re: TeamGrumman-List: PowerFLow --> TeamGrumman-List message posted by: FLYaDIVE@aol.com In a message dated 9/19/06 11:17:25 AM Eastern Daylight Time, 923te@cox.net writes: > Since Powerflow has been brought up again I thought I would comment. > > I am quite curious how PowerFlow got thru the STC process seeemingly so > easily.... > > Compared to what trouble the FAA is giving Gary with a far better cowl than > available anywhere for our grummans. > > I guess once you have worked with the FAA for several years and acheived > several STC's they cut you some slack > > I am suspicious that the short stack approval process did not check out a > lot of things....like the effects to air flow and cooling by interrupting the > exit ramp flow or the additional heat gain inside the cowl which I think has > shortened a few owners battery life. > > Things I wish were addressed now that I bought into the short stack. > > Just venting and hoping Gary's cowl gets approved soon...hang in there Gary > and don't let those FAA weenies stop you. > > Regards, > Ned ============================== "Green Paper makes for a Slippery Runway" Barry "Chop'd Liver"