Return-Path: <13brv3@bellsouth.net> Received: from imf20aec.mail.bellsouth.net ([205.152.59.68] verified) by logan.com (CommuniGate Pro SMTP 4.1.8) with ESMTP id 2910047 for flyrotary@lancaironline.net; Mon, 29 Dec 2003 20:12:02 -0500 Received: from rad ([68.155.98.142]) by imf20aec.mail.bellsouth.net (InterMail vM.5.01.06.05 201-253-122-130-105-20030824) with ESMTP id <20031230011201.HEVL1881.imf20aec.mail.bellsouth.net@rad> for ; Mon, 29 Dec 2003 20:12:01 -0500 From: "Russell Duffy" <13brv3@bellsouth.net> To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Re: aluminum hose bungs/fittings Date: Mon, 29 Dec 2003 19:12:03 -0600 Message-ID: <001f01c3ce71$ef335190$6001a8c0@rad> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0020_01C3CE3F.A498E190" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.4510 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1165 Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0020_01C3CE3F.A498E190 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Thanks for all the comments and suggestions. Hey Jim, that's one funny looking firewall :-) BTW- the tubes on the cores that I got are about = 9/16" diameter for the largest one, so I won't be using either of the factory tubes. =20 =20 Wrap the end of the core with a few layers of soaking wet towel while welding on the fittings. =20 Thanks for all the construction tips Lynn, particularly this bit about = the wet towels. As I've thought of welding these things, I couldn't help = but wonder how much of the factory core I would be un-welding in the = process. How exactly are these constructed? I assume they're brazed, and = something of a lower temp than welding?? =20 =20 The cores will have oil in them that circulates in the system to = lubricate the compressor. Let them drain for a few days and the rinse them out = with ketone or similar and then soap and water. Blow it out to get it as dry as = possible before welding. If you short cut this step, be aware that the jet of = orange oil vapor flame that shoots out of the proposed fitting holes is about a foot long and will blow your welding helmet clean off of your head. =20 Another wise piece of advice. I haven't looked for junk cores, but the problem I've found with the new ones is that none of them are made the = same. I had planned to do plenty of practice on similar thicknesses of = aluminum, and then try the new core. If I screw up enough of them, I'll surely be looking for some of those junk cores for more practice. =20 These things work well for water or oil cooling. They are tough as = nails. (the GM stuff). If you have room, you can cut one side off of a bulkhead fitting and use the hex as a welding flange. Better for oil cooling where the fittings hose ends are going to be heavy anyway. For water service, the AN = fittings and hose ends will be too big (dash 16 or 20) and too heavy. =20 I thought about the cut off fitting, but aluminum AN bungs are pretty reasonably priced, so I'll probably just use those. With everything in place this afternoon, it looks like I have room to use an AN-12 bung (remember, parallel cores) and 90 degree hose fitting, so I'm leaning strongly toward going that route. As much as it pains me to buy all = that AN hose, it's really the "right" thing to do. I'm sure the silicone hose = is perfectly fine, but the more I can conform to "aircraft quality", the = less grief I'll get from all the people who look at it. I think Tracy = actually mentioned this as a significant downside to using auto hose. =20 Mount the core in foam lined brackets. Don't let anything rub against = them (but a foam seal strip). I have the cores attached to the redrive plate with aluminum angle on = top, and bottom. The idea was to weld the angle to the cores, then bolt it = to the redrive plate. I hadn't planned to put any sort of rubber = dampening, since the cores are very solidly mounted (can't twist, or bend). Should = I put a 1/8" or so piece of rubber between the angle and mounts? That = just doesn't strike me as a good idea, but I'm open to suggestion. =20 =20 Also, when mounting the cores to the angle. I planned to weld the angle = to the cores on top and bottom, but for test fitting, I drilled and clecoed = the angle to the end plates on the core. With only 6 clecoes, this thing is VERY solid. I'm now wondering if I couldn't just put about a dozen 1/8" = pop rivets, rather than welding the angle. I have to admit, that I'm = thinking about easy of replacement if one ever gets damaged away from home. = Assuming I keep a spare core with two AN12 fittings welded to it, all I'd have to = do to replace a core is drill out the rivets, then drill and pop rivet the = new core. This may sound paranoid, but I know that Ed and Finn have both replaced leaking cores. I'm also thinking about lessoning the chance of damaging a core by overheating it with the torch. =20 =20 Thanks, Rusty (sure would be easier if it was at home) =20 ------=_NextPart_000_0020_01C3CE3F.A498E190 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable Message
Thanks for all the comments and suggestions.  Hey = Jim, that's=20 one funny looking firewall :-)  BTW- the tubes on the cores that I = got are=20 about 9/16" diameter for the largest one, so I won't be using either of = the=20 factory tubes. 
 

Wrap the end of the core with a few layers of soaking = wet towel=20 while welding
on the fittings.

 
Thanks = for all the=20 construction tips Lynn, particularly this bit about the wet = towels.  As=20 I've thought of welding these things, I couldn't help but wonder how = much of the=20 factory core I would be un-welding in the process.  How exactly are = these=20 constructed?  I assume they're brazed, and something of a lower = temp than=20 welding?? 
 
The cores will have oil in them that circulates in = the system=20 to lubricate
the compressor. Let them drain for a few days and the = rinse them=20 out with ketone
or similar and then soap and water. Blow it out to = get it as=20 dry as possible
before welding. If you short cut this step, be aware = that the=20 jet of orange
oil vapor flame that shoots out of the proposed fitting = holes=20 is about a foot
long and will blow your welding helmet clean off of = your=20 head.
 
Another = wise piece of=20 advice.  I haven't looked for junk cores, but the problem I've = found with=20 the new ones is that none of them are made the same.  I had planned = to do=20 plenty of practice on similar thicknesses of aluminum, and then try the = new=20 core.  If I screw up enough of them, I'll surely be looking for = some of=20 those junk cores for more practice. 


These things work well for water or oil cooling. They are = tough as=20 nails.
(the GM stuff). If you have room, you can cut one side off of = a=20 bulkhead fitting
and use the hex as a welding flange. Better for oil = cooling=20 where the fittings
hose ends are going to be heavy anyway. For water = service,=20 the AN fittings
and hose ends will be too big (dash 16 or 20) and too = heavy.
 
I thought about the cut = off fitting,=20 but aluminum AN bungs are pretty reasonably priced, so I'll probably = just use=20 those.  With everything in place this afternoon, it looks like I = have room=20 to use an AN-12 bung (remember, parallel cores) and 90 degree hose = fitting,=20 so I'm leaning strongly toward going that route.  As much as it = pains me to=20 buy all that AN hose, it's really the "right" thing to do.  I'm = sure the=20 silicone hose is perfectly fine, but the more I can conform to = "aircraft=20 quality", the less grief I'll get from all the people who look at=20 it.  I think Tracy actually mentioned this as a significant = downside=20 to using auto hose.   

Mount the core in foam = lined=20 brackets. Don't let anything rub against them
(but a foam seal=20 strip).

I have the = cores attached=20 to the redrive plate with aluminum angle on top, and bottom.  The = idea was=20 to weld the angle to the cores, then bolt it to the redrive plate.  = I=20 hadn't planned to put any sort of rubber dampening, since the cores are = very=20 solidly mounted (can't twist, or bend).  Should I put a 1/8" = or so=20 piece of rubber between the angle and mounts?  That just doesn't = strike me=20 as a good idea, but I'm open to suggestion. 
 
Also, when mounting the = cores to the=20 angle.  I planned to weld the angle to the cores on top and bottom, = but for=20 test fitting, I drilled and clecoed the angle to the end plates on the=20 core.  With only 6 clecoes, this thing is VERY solid.  I'm now = wondering if I couldn't just put about a dozen 1/8" pop rivets, rather = than=20 welding the angle.  I have to admit, that I'm thinking about easy = of=20 replacement if one ever gets damaged away from = home.  Assuming I=20 keep a spare core with two AN12 fittings welded to it, all I'd have to=20 do to replace a core is drill out the rivets, then drill = and pop=20 rivet the new core.  This may sound paranoid, but I know that Ed = and Finn=20 have both replaced leaking cores.  I'm also thinking about = lessoning=20 the chance of damaging a core by overheating it with the=20 torch.  
 
Thanks,
Rusty (sure would = be easier if=20 it was at home)   
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