Exhaust system

[jstall]

Fellow members, took a look at my Taylorcraft today and noticed the tail pipe had fell off
yep gone, came thru the heat shroud, is the original style B type. just eroded away and
fell off on last flight.

Wag Aero has one that says original. what are you thoughts on this, and they also mentioin
that the engine must be removed to replace this? Wondering if I could slide a pipe over the
old stub and weld it up. as a fix Your thoughts on that also

J Stallings
Member/Alva, OK
N95093

[Hank Jarrett]

Re: Exhaust system

I have an exhaust in the hangar with a pipe over the rusted off one and welded. Never used it but I would think the best thing to do is ask your IA if he would sign it off as a repair. After all he is really the one who is putting his signature on the line. I see no safety, engineering or operational reason you couldn't repair one that way, but I wouldn't be the one signing off the paperwork.

Hank

[M Jones]

Re: Exhaust system

I've purchased a few Taylorcraft exhausts over the years from Wag Aero, never had any issues with their stacks. I've also had some repaired as you describe. Like Hank said, it's up to the IA to sign off, but I've had no problem getting it done if everythig else is still solid. Last year, the last mild steel exhaust I had started to develop a hole in the down pipe while flying in eastern Colorado. I put a temporary patch on it and had a stainless steel one made when I got home. Hopefully I won't have to go through all that again anytime soon. The tricky part of buying a new stack off the shelf is making sure that it fits what you currently have. Univare also makes exhaust stacks, but they won't work with a shroud that fits the Wag unit, and the Wag stack won't work with the Univare shroud. Univare mentions that in the part description. Wag will tell you that if you give them a call. Wag is also a certified repair station if you want to remove your present stack and send it to them for repair. If you decide to buy new from Wag Aero, I would call them and send your shroud to them so they can verify the correct fit first.

[Guest]

Re: Exhaust system

Check out AC43.13-1B, the chapter on exhausts.

It says there that exhaust system tubing can be repaired using the methods for tubing repair in chapter 4.

Chapter 4 is where all the tube repairs A&P's are familiar with are listed.

So any A&P can do a "larger diameter splice" (I forgot the figure number) and weld on the next size bigger tube.

He will have to do a 337 form for it.

Pretty simply repair, perhaps can be done with exhaust in place.

Dave R

[3Dreaming]

Re: Exhaust system

Check out AC43.13-1B, the chapter on exhausts.

It says there that exhaust system tubing can be repaired using the methods for tubing repair in chapter 4.

Chapter 4 is where all the tube repairs A&P's are familiar with are listed.

So any A&P can do a "larger diameter splice" (I forgot the figure number) and weld on the next size bigger tube.

He will have to do a 337 form for it.

Pretty simply repair, perhaps can be done with exhaust in place.

Dave R

I have never seen a 337 for a repaired exhaust before.

I also don't see repairs of exhaust listed in CFR 43 appendix A either.

What is your justification for saying it needs a 337?

[jstall]

Re: Exhaust system

I have an exhaust in the hangar with a pipe over the rusted off one and welded. Never used it but I would think the best thing to do is ask your IA if he would sign it off as a repair. After all he is really the one who is putting his signature on the line. I see no safety, engineering or operational reason you couldn't repair one that way, but I wouldn't be the one signing off the paperwork.

Hank

Hank, that was my 1st idea also, there is plenty of pipe above where it came off, and would
be pretty easy fix actually on the a/c. pull cowl heat muff and slide a oversize pipe up over
and tack er in place. What is the OD of the tail pipe??

JS

[3Dreaming]

Re: Exhaust system

Hank, that was my 1st idea also, there is plenty of pipe above where it came off, and would
be pretty easy fix actually on the a/c. pull cowl heat muff and slide a oversize pipe up over
and tack er in place. What is the OD of the tail pipe??

JS

I would measure what you have, instead of relying on someone else's measure. Thiers might be different.

[jstall]

Re: Exhaust system

I would measure what you have, instead of relying on someone else's measure. Thiers might be different.

Do you have to remove engine and mount from firewall to get the exhaust system off
the engine??

JS

[3Dreaming]

Re: Exhaust system

Yes

[Scott]

Re: Exhaust system

I can't help but think that if the tailpipe was corroded so much that it departed the aircraft, the rest of the exhaust is probably not that great either. Localized corrosion is possible I guess but I think you will want to do a thorough inspection of the remainder of the exhaust before making any repairs.

Also, just because there is some tailpipe remaining, doesn't guarantee you can weld to it. Steel of exhaust systems gradually gets to the point where there is too much carbon and can't be welded successfully. If I was going to attempt a repair, i'd be inclines to remove the entire tailpipe at the cross-tube and fabricate a whole new tailpipe. If you're looking a paying someone to do it, i suspect it will be the same or less money to install a new Wag Aero unit.

I purchased the Wag exhaust and I'm satisfied that it is a decent replacement. It is not stainless (but a third the cost) and the fit seems to be good.

Exhaust failures on smaller normally aspirated engines are not as critical as on larger boosted engines (eg wing failures due to burnt through spars), but it's still an area that should command attention. Exhaust leaks cause fires and carbon monoxide poisoning, two things we all should be very afraid of, and consider when making exhaust related decisions.

[jstall]

Re: Exhaust system

I can't help but think that if the tailpipe was corroded so much that it departed the aircraft, the rest of the exhaust is probably not that great either. Localized corrosion is possible I guess but I think you will want to do a thorough inspection of the remainder of the exhaust before making any repairs.

Also, just because there is some tailpipe remaining, doesn't guarantee you can weld to it. Steel of exhaust systems gradually gets to the point where there is too much carbon and can't be welded successfully. If I was going to attempt a repair, i'd be inclines to remove the entire tailpipe at the cross-tube and fabricate a whole new tailpipe. If you're looking a paying someone to do it, i suspect it will be the same or less money to install a new Wag Aero unit.

I purchased the Wag exhaust and I'm satisfied that it is a decent replacement. It is not stainless (but a third the cost) and the fit seems to be good.

Exhaust failures on smaller normally aspirated engines are not as critical as on larger boosted engines (eg wing failures due to burnt through spars), but it's still an area that should command attention. Exhaust leaks cause fires and carbon monoxide poisoning, two things we all should be very afraid of, and consider when making exhaust related decisions.

Yes Scott, I agree, we won't know what we have there till we get it apart, I'm going to wait for the A&P I.A. to get back from California to tear into it. If the system looks fair I might even ask about brazing it with brass rod over the top of the tube, I.E. SLIDE A TUBE OVER THE EXISTING TUBE AND BRAZE IT, this would seal it as well as produce a strong bond, like you say its not boosted and only serves to get the exhaust gas into the
slip steam. Thanks for the response

JS

[jstall]

Re: Exhaust system

Also, anyone, to get the exhaust off you have to pull the engine? if I'm understanding correctly. Do you separate
via the engine mounts i.e. rubber eng mounts or at the firewall. And if it is the firewall, are those bolts accessable
on the back side to be held while unbolting and then re bolting, I know the fuel tank is there and was wondering what
kind of issue that might present. Please help me understand this

JS

[NC36061]

Re: Exhaust system

JS,

If you use the search function, you will find tons of info. Here is just one thread, there may be better ones too. Yes, from the firewall, yes, the bolt heads are inside, yes its a pain. A much simpler solution is to cut the old system off and install a Luscombe, Aeronca or C-150 system, but that requires modifying cowling and buying an STC, which you are probably not inclined to do since you are contemplating a repair vs. new system.

http://vb.taylorcraft.org/showthread.php?11718-Proper-way-to-remove-and-install-exhaust-n-BC12-&highlight=exhaust+engine+mount

Edit: I just looked at a couple of bare fuselages. There are small flanges welded to fuselage tubing adjacent to the engine mount bolt fittings that should hold the bolt heads in place as you remove the nuts from the firewall-forward side, so you shouldn't need a wrench or socket on the bolt head inside to remove the mount.

[Guest]

Re: Exhaust system

I have never seen a 337 for a repaired exhaust before.

I also don't see repairs of exhaust listed in CFR 43 appendix A either.

What is your justification for saying it needs a 337?

Hi Tom,

Bad memory is the only justification. Sorry for the mess up.

You are correct no 337 required I must have gotten confused by the alteration portion on Appendix A...

"(xii) Changes to the basic design of the fuel, oil, cooling, heating, cabin pressurization, electrical, hydraulic, de-icing, or exhaust systems. "

But this is not an alteration. My bad thanks for catching that and clearing it up.

Dave R

[N96337]

Re: Exhaust system

I was taught that when we had to weld more than a fraction of an inch, it was a major repair. I have seen 337's for exhaust repairs, but mostly you see repair station tags instead, as it's not that common to have them repaired in the field anymore.
John