Weight Gain - Composite Pipes

Wed Sep 24 07:00:24 AKDT 2003

I was asked to forward this to the NSRCA list by Wayne Powell (Bolly North America)...thanks...

<<"The carbon pipes absorb a lot of the oil" 

"Of course weight gain due to exhaust soak can be an issue with some of the more porous composite pipes (like the Bolly) but IMHO it is nonexistent with the ES pipes."

Hmm, this is the second time I've seen statements like this made, yet I've not come across this in almost 10 years of selling our composite pipes. The other gent who mentioned it (--Lance) sent me a really well used pipe from a friend of his to test. Problem was it had a glassed on "stinger" so comparisons of the pipe weights to a new one were impossible. That said, the other pipes that I and our sponsored guys run (I know, a potential bias here) haven't gained measurable weight. Granted, my scale is +/- 5 grams so there's some tolerance there, however, I'm not bought in to the idea of a pipe gaining 3 ounces, or anywhere near that, over it's useful life. The only way to have the pipe gain weight by absorbing oil would be if the resin was cooked completely out of the composite weave, and the remaining oil offset the lost resin. This will happen if the pipe has insufficient airflow around the outside and neck of the pipe, however you'll notice the neck going black (WARNING SIGN) if this is happening. 

I can't speak to the ES pipes, as frankly I don't know what composites they're using and/or if they suffer these problems. I've heard of the crushed/melted neck thing, however, anything can be broken if we try hard enough! Our older pipes have the composite necks, but the 140Rs have an aluminum neck portion to take the heat punishment our 4Cs dish out. Of course, the snag here is that the expansion rates are different between the alloy and the composite, and if one yanks on the neck while the pipe is hot, we get a "plug in pipe". Agree there is no perfect answer - at least that I'm aware of.

As for saving 4 ounces, it takes a LOT of balsa dust to make that up! On a dollars per ounce basis, savings in the exhaust system are much less expensive than many other components of our planes - that's what got me turned on to them in the first place.

Just my opinion of course...flame away!

Wayne Powell

Bolly Props North America

http://www.BollyProps.com >>

Bob Pastorello 

> 
> From: Jerry Budd <jbudd at QNET.COM>
> Date: 2003/09/24 Wed AM 09:53:10 EDT
> To: discussion at nsrca.org
> Subject: Extreme Weight Savings [was: ES Composite Pipe Repair]
> 
> Sure Del, like most things I just have to find (make) time to do it.
> 
> Don Ramsey also has me on the hook for an article on some judging 
> issues I noticed at the Nats.
> 
> Anybody want to build an Excellence for me while I'm busy writing 
> these articles?   :-)
> 
> Thx, Jerry
> 
> 
> >Jerry.
> >      In all seriousness would you consider submitting for 
> >publication your efforts? I for one would be very interested as many 
> >others I suspect. Mark Sheda did such many years ago and think it 
> >may be time to revisit that issue to the extreme you mention.
> >
> >      Del K. Rykert
> >      AMA - 8928
> >      NSRCA - 473
> >      Kb2joi - General
> >
> >
> >
> >----- Original Message -----
> >From: <mailto:jbudd at QNET.COM>Jerry Budd
> >To: <mailto:discussion at nsrca.org>discussion at nsrca.org
> >Sent: Wednesday, September 24, 2003 1:27 AM
> >Subject: Re: ES Composite Pipe Repair
> >
> >Hey Ed,
> >
> >Nobody is better qualified to speak to this than I.  I absolutely
> >killed myself to get my E=MC3 down to make weight at this years Nats.
> >A month prior my E=MC3 weighed 11 lbs, 12 oz.  I had Dick Hanson
> >build me a new set of wings to get within a couple of ounces and then
> >I started looking at weight on a gram by gram basis at the component
> >level.  At the courtesy weighing on Sunday at the Nats I was 18 grams
> >over weight.  I then took 2.3 ounces of weight out of the airplane
> >and I exactly made weight at the weight checks late Wed and also
> >after the finals on Thurs.  I'll leave the math to those who feel
> >compelled to check my numbers (Hint: no, it doesn't add up!  BTW -
> >Did you know that a standard JR switch harness/charge jack assembly
> >w/screws weighs 1 ounce?).  Last year I pulled 11 ounces out of a
> >Gator G202 to get under weight for the Nats but it didn't matter
> >since I had engine problems on Monday.  Maybe I should write an
> >article sometime on how to REALLY get serious about getting the
> >weight out of an obese airplane?
> >
> >Anyway, my experience with the carbon fiber pipes is that they are
> >the second easiest/quickest way to save weight at the component level
> >via substitution (changing from an aluminum wing tube to a carbon
> >fiber tube is the first, wheels are third, and the fuel tank comes
> >fourth).  Of course weight gain due to exhaust soak can be an issue
> >with some of the more porous composite pipes (like the Bolly) but
> >IMHO it is nonexistent with the ES pipes.
> >
> >As far as the problems with inlet temperature I haven't seen this
> >when running a 2-stroke motor so I'd have to say that it's one of
> >those costs associated with running a 4-stroke.  My ES pipes are now
> >3 years old and in nearly perfect operating condition (I've been
> >4-stroke free since 2000).
> >
> >Jerry
> >
> >
> >>You wouldn't believe the lengths ( read $$ and time ) I went to to
> >>shave mere grams from my EMC. The ES pipe I have weighs exactly 3
> >>oz. I'm all for the durability and cost reduction of an aluminum
> >>pipe over unobtainium, but that ounce plus is sure hard to find
> >>elsewhere.
> >>Ed M.
> >>
> >>----- Original Message -----
> >>From: 
> >><<mailto:Rcmaster199 at aol.com>Rcmaster199 at aol.com>mailto:Rcmaster199 at aol.com>Rcmaster199 at aol.com
> >>To: 
> >><<mailto:discussion at nsrca.org>discussion at nsrca.org>mailto:discussion at nsrca.org>discussion at nsrca.org
> >>Sent: Tuesday, September 23, 2003 7:35 PM
> >>Subject: Re: ES Composite Pipe Repair
> >>
> >>Maybe it's me but I just don't get this apparent love affair
> >>with the carbon pipes. Epoxy as the binder, as Gray states, is
> >>marginal in almost all 4 stroke cases I have heard about. And to
> >>make these things super light, you have got to make then thin, so
> >>strength is doubly compromised, especially on four strokes with
> >>their 500+ degree stack temp.
> >>
> >>A hi temp plastic binder such as a PTFE emulsion, or maybe polyimide
> >>emulsion is a better alternative but then the cost would be 2x and
> >>impractical.  And ceramics, aka Space Shuttle heat shield tiles, are
> >>out of this world (sorry Gray, I couldn't resist)
> >>
> >>How much weight is actually saved over a "lightweight"ally pipe
> >>anyway? The Greves is a little over 4 ounces, the Macs 20 cc is a
> >  >little over 5 ounces and the Hatori is a little over 6. Are we
> >>talking, what, 4 ounces tops?? Isn't there someplace else one could
> >>remove 2 to 4 ounces?
> >>
> >>Hey, I am a big proponent of progress and composites offer great
> >>advantages in the correct places, but I have to question if this is
> >>one of these places
> >>
> >>Firesuit..... hell forget the firesuit> I'm thick skinned enough,
> >>literaly, so fire away
> >>
> >>matt K
> >>
> >>>Subj:Re: ES Composite Pipe Repair
> >>>Date:9/23/2003 6:38:01 PM Eastern Daylight Time
> >>>From:<<mailto:edbon85 at optonline.net>edbon85 at optonline.net>mailto:edbon85 at optonline.net>edbon85 at optonline.net
> >>>Reply-to:<<mailto:discussion at nsrca.org>discussion at nsrca.org>mailto:discussion at nsrca.org>discussion at nsrca.org
> >>>To:<<mailto:discussion at nsrca.org>discussion at nsrca.org>mailto:discussion at nsrca.org>discussion at nsrca.org
> >>>Sent from the Internet
> >>>
> >>>
> >>>
> >>>Gray, I'm listening. A short lived $200 plus pipe is not affordable
> >>>either. Short of going back to aluminum and the weight penalty, do
> >>>we have another alternative ??
> >>>Ed M.
> >>>
> >>>>----- Original Message -----
> >>>>From: 
> >>>><<mailto:gfowler at raytheon.com>Gray>mailto:gfowler at raytheon.com>Gray 
> >>>>E Fowler
> >>>>To: 
> >>>><<mailto:discussion at nsrca.org>discussion at nsrca.org>mailto:discussion at nsrca.org>discussion at nsrca.org
> >>>>Sent: Tuesday, September 23, 2003 5:40 PM
> >>>>Subject: Re: ES Composite Pipe Repair
> >>>>
> >>>>
> >>>>
> >>>>Concerning this repair, there is not a commercially available
> >>>>adhesive that is going to do the job long term. The adhesive I
> >>>>used on Wayne's pipe is an aerospace grade epoxy called Hysol
> >>>>9394, rated at 350F. AT 350F this epoxy exhibits about 25% of its
> >>>>room temperature strength-and this is about the best room
> >>>>temperature curing high temp epoxy available-in short  all the
> >>>>stuff such as JB weld is crap at the temperatures we are talking
> >>>>about. The inlet temp of our mufflers makes for a brutal
> >>>>environment and unfortunately anything that cures at room
> >>>>temperature just is not going to do the job very well. In reality
> >>>>Hysol 9394 is borderline. No easy answer here, and is evident by
> >>>>the constant postings about burned out inlets....there is a
> >>>>problem with the composite mufflers.  Actually there is an answer,
> >>>>but I do not think our pattern market can afford it.
> >
> >
> >--
> >___________
> >Jerry Budd
> ><mailto:jbudd at qnet.com>mailto:jbudd at qnet.com
> >=====================================
> ># To be removed from this list, send a message to
> ># <mailto:discussion-request at nsrca.org>discussion-request at nsrca.org
> ># and put leave discussion on the first line of the body.
> >#
> 
> 
> -- 
> ___________
> Jerry Budd
> mailto:jbudd at qnet.com
> =====================================
> # To be removed from this list, send a message to 
> # discussion-request at nsrca.org
> # and put leave discussion on the first line of the body.
> #
> 
> 

Bob Pastorello, El Reno, OK, USA
rcaerobob at cox.net
www.rcaerobats.net

=====================================
# To be removed from this list, send a message to 
# discussion-request at nsrca.org
# and put leave discussion on the first line of the body.
#