My first Piper...

[Kodiakmack]

I’m closing in a few days on a PA-12! She’s N3969B that MT12 rebuilt. She got a clean bill of health from Mike Butterfield of Yakima Aerosport today, and I hope to fly her home next week. I’m looking forward to lots of fun and plenty of learning along side all of you. Pictures and details to come. Yahoo!

[MT12]

I hope you enjoy her as much as I did, glad she got a clean bill of health.

Doug

[Kodiakmack]

I hope you enjoy her as much as I did, glad she got a clean bill of health.

Doug

Doug, Mike was very complimentary of your work. He said she'll outlive us all if I hangar her. I'll be in touch soon, and will fly up there at some point for a visit!

[Kodiakmack]

Finally I have some time to make a quick post-purchase report

Financing came through with Red River State Bank in Minnesota. Big shout out to Larry at that bank. He bent over backwards and worked really hard to make everything happen really fast. There was a snag before closing as there was an old lien on the airplane from the 90's. The seller ended up having to pay a title company to square it away, but it got sorted. The lien had been released, but the bank either never filed the paperwork with the FAA, or the FAA lost it.

My dad and I flew his Lake LA-4 from Ogden UT up to Moses Lake with a fuel stop at La Grande Oregon. After picking up the bird, I enjoyed one of the highlights of my flying career, flying in formation with my Dad back to McCall, over Hells Canyon. Other than pretty heavy smoke, it was a beautiful flight, and an amazing bonding experience. The next morning Dad and I did about 12 landings in the LA-4 on Payette Lake to seal the deal on a grand couple of days.

So here she sits, cozily hangared in McCall while I finish up fire season before flying her home to Ogden. My Dad and I are working on making a comprehensive spreadsheet to organize the history of the bird and make a maintenance plan and keep things in order.

There's not much I NEED to do to the airplane, but there are a few items that I'll be trying to tick off as money allows (the purchase and everything involved in getting it home have me pretty cash poor). First on the list is going to be a 4 cylinder engine monitoring system. I'd really like to go STC and replace all of the engine cluster, but may end up going non-STC'd to save $. The prop on the plane is old and undocumented, and is a cruise prop at 74/56. I'd love to find a decent used borer, but haven't seen much, so may have to go new. Other than those things and a few little things, I think I'll be set to fly her through the winter and into next fire season when the overtime hose will turn back on, and I'll be able to afford some more upgrades.

Thanks to everyone for all their help here getting me here. I'm looking forward to sharing the joy of this airplane with many!

[cubdriver2]

Just enjoy your new baby for a couple hundred hours just the way it is. Simple is better, I've never had anything but temp and oil pressure. All my friend with all the fancy info monitors are always a nervous wreck.

Glenn

[hotrod180]

..... First on the list is going to be a 4 cylinder engine monitoring system. I'd really like to go STC and replace all of the engine cluster, but may end up going non-STC'd to save $. .....

Congrats on your purchase!
I was wondering if you'd elaborate on this comment.

[Kodiakmack]

Congrats on your purchase!
I was wondering if you'd elaborate on this comment.

as it sits, the airplane has oil press/temp, rpm. It’s my belief that an engine monitor that includes CHT/EGT on each cylinder (not to be fawned over and worried by) as well as fuel flow, pays for itself in no time by Allowing one to accurately lean, and by allowing easy troubleshooting of any engine malady. As it sits if I get a rough running engine, high/ low oil temp/press, I’m going to need to look into every cylinder for an answer. If I ca tell my mechanic that the number 2 cylinder is running hot/cold then they can save a lot of shop time and start with the offending cylinder right away. So between shop costs and burning the correct and hopefully lesser amount of fuel, the savings add up pretty quick. Plus I like that kind of data.

as for the STC vs not, as far as I understand means the difference between the digital monitor being installed ALONG WITH the original engine gauges that are there now. If you go STC, you can REPLACE the current instruments, cleaning up the aesthetics of the panel. Eventually I’d like just two instruments, one for the engine cluster, and the other for altitude, airspeed, etc.

[skywagon8a]

In the meantime turn off one mag, pull the mixture until it just starts to run rough, richen it until just smooth, turn on both mags. Then when you get your fancy instrument compare it to this procedure. You will not find any difference.

[Kodiakmack]

This potentially takes care of one thing out of several that I would find an instrument useful for. Not asking you to put one in your plane : )

[skywagon8a]

In the meantime turn off one mag, pull the mixture until it just starts to run rough, richen it until just smooth, turn on both mags. Then when you get your fancy instrument compare it to this procedure. You will not find any difference.

This potentially takes care of one thing out of several that I would find an instrument useful for. Not asking you to put one in your plane : )

I've been using these muti cylinder temperature indicators for decades, for all the reasons you have mentioned. My only purpose was to give you a leaning method while you build your cash reserves.

A side note: The method I've described does not work on my Cub which has balanced fuel injectors and dual electronic ignition. The engine never runs at all rough while leaning, whether on single or dual ignition. It just slowly looses power as the mixture is moved towards lean, until the engine stops. The multi-cyl EGT instrument is a must in this case, in order to have any idea of the proper fuel/air ratio.

[Kodiakmack]

Roger that. Sorry if I came off snippy. I read that as a “hey dumb kid you don’t need that shtuff” and I’ve been getting “hey dumb kid” type comments for 15 years and 7,000 hours lol. I should probably relax.

Anyways....I ordered an EdM 900 and will install that this winter : )

[skywagon8a]

You are forgiven. I see that you are a new member here. We are not the ordinary internet wisea$$e$. We are one big happy family who try to keep everyone happy and safe. There is often a bit of sarcasm thrown in, all in jest. Your new -12 will appreciate your becoming a member of the SC.org family. I already knew your own family knew how to enjoy aviation when you mentioned your Dad's LA-4. That is a good learning tool and a lot of fun to fly. I cut my teeth in seaplane flying with a Colonial C-1.

[Kodiakmack]

So I’m deep into doing an annual with my dad on the cruiser. I’m not going to list all the problems we are running into as there’s nothing crazy, but one thing we did find today is a crack on a nearly new muffler. Wondering if anyone knows a. If this can be welded for repair. b. Who a reputable shop is to have that repair done and c. What I could expect to pay for said repair.

The other option is my friend’s old muffler assembly off his O320 -18. Will this work on a -12 or is the exhaust airframe specific or stc specific for the kenmore install of the o320?

[Kodiakmack]

my cracked exhaust, and my friend’s -18 o-320 exhaust

[mvivion]

Cracks can be and are welded all the time. Most recently I’ve used Acorn.

MTV

[mike mcs repair]

my cracked exhaust, and my friend’s -18 o-320 exhaust

Edit. Never mind that muffler is junk. Cracked.

Need to see pictures of the muffler that was under that schroud ?? Looks like you also have a broken muffler by the exhaust stains near cracks,...


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[PerryB]

In the meantime turn off one mag, pull the mixture until it just starts to run rough, richen it until just smooth, turn on both mags. Then when you get your fancy instrument compare it to this procedure. You will not find any difference.

Why one mag? Shutting one off effectively retards the timing slightly but has no other effect on fuel demand. The optimal mixture will still be the same for a given load condition.

[skywagon8a]

Because with one mag you can feel the roughness sooner than with two mags. It is telling you a more precise mixture setting. Try one mag to the point of just getting rough and then turn on both mags. The roughness will disappear.

Why do you say the timing will be retarded on one mag when they are both timed the same?

[PerryB]

EFFECTIVELY retards the timing because now the flame front has to cross the entire cylinder instead of two fronts that meet in the middle. The doubling of the time required for full combustion to occur causes peak cylinder pressure to come several degrees later in crank rotation. That's why the drop in RPM. I'll try the one mag leaning next time.

[Kodiakmack]

Would really like to see some pictures of people’s setup for the tailpipe to riser support rod system. I’m keeping the 0235 spring/rod muffler support because why not. But I’m still confused about how linking the tailpipe to the riser with a solid connection helps reduce wear on the muffler/tailpipe?

[Gordon Misch]

Piper's setup worked well on my -12 both with O235 and O320. Never any issues with exhaust system cracking. FWIW - -

I have the Sutton system now and it's been trouble free for the 10 years since I installed it.

[Kodiakmack]

Thanks for that. I plan to install the Sutton first chance I can afford, but for the time being hope to make repairs and get the support system right. This muffler cracked due to there effectively being no support whatsoever.

[Gordon Misch]

When rebuilding I had purchased a used -18 exhaust system because I liked the crossover arrangement. I thought it might be more efficient than the stock -12 system. But it was so crowded between engine and firewall, that I threw up my hands, sold that, and bought the Sutton.

This is is purely speculation, but I think an exhaust system that has exhaust pulses pushing against each other, plus the right angle turns the exhaust gas has to make in the normal muffler arrangements we see doesn't make much sense. But then, for certified planes we don't have a lot of choice. If exp, a "tuned" system makes all kinds of sense.

A likely irrelevant aside.... when in school, one of the profs offered me the opportunity to substitute designing and making a tuned exhaust for a 65 Continental, in lieu of the prescribed fluid mechanics lab. When done, he said it did give increased RPM/power over whatever he had previously installed.

If experimental, I'd certainly be more than interested in the Vetterman system. If certified, ..... oh well!

[skywagon8a]

But I’m still confused about how linking the tailpipe to the riser with a solid connection helps reduce wear on the muffler/tailpipe?

The vibration in the tail pipe shaking has to be supported where the weld is located on the muffler can. Exactly where the crack in your muffler is located. That joint gets constant vibration forces which it needs to resist. It can't, so over time it cracks. The brace from the lower tail pipe up to the main exhaust near the first joint provides stability to resist that vibration.

That looks like a well done patch from a previous crack. Had the brace been installed at the time of that cracking, the repair would not have cracked.

[Scooter7779h]

Here is my PA-12 (was stewartb's -12 rebuild done with Mike MCS ). It is a short mount Crosswinds STOL STC install, with and Atlee Dodge Hot Rod PA-18 muffler. The Crosswinds STC includes the conviersion to the PA-18 exhaust, uses stock PA-18 exhaust parts, with no modification.

[stewartb]

my cracked exhaust, and my friend’s -18 o-320 exhaust

The crack isn’t unusual. Add a brace but you’l still need to inspect it. Skywagon guys have fought tailpipe cracks for decades. There’s no place to brace it. Gussets have been added, bridge plates, and even damming around it the area and cutting back the shroud has been done. The issue isn’t so much the crack but where the crack is. Carbon monoxide is a threat. Do what you can to prevent exposure to it.

[dgapilot]

Do yourself a favor and bite the bullet on the Sutton exhaust now. Yes, you can try to repair it, but more than likely it will crack again in short order. The Sutton is lighter, and gets the heat away from the accessory section, moving it forward.


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[MT12]

Do yourself a favor and bite the bullet on the Sutton exhaust now. Yes, you can try to repair it, but more than likely it will crack again in short order. The Sutton is lighter, and gets the heat away from the accessory section, moving it forward.


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But time it with the replacement of your bottom cowl as I think the hole is in a different spot

[Charlie Longley]

But time it with the replacement of your bottom cowl as I think the hole is in a different spot

Cut a new hole and patch the old one. Yep bite the bullet and buy the Sutton exhaust.

[Kodiakmack]

Moving right along into tail spring woes. I rebuilt my 3200 and ordered a brand new tail spring set as well as a new u shaped spring clamp and pad from univair. I’ve read much about others finding that their springs come incorrectly shaped from there. When We try to install the new spring there is a large gap between the spring and the clamp mounting pad that would require an insane amount of tightening on the bolts that mount the clamp/spring to the pad. Will this be sufficiently relieved once the weight is back on the wheel? We don’t have much tailwheel experience here and this seems incorrect. I’ve attached a picture of the spring in position as well as the top and bottom springs in comparison to the old spring.

[Crash, Jr.]

Looks like your rear spring mount was replaced and re-welded with a Maule spring pack instead of a Piper one. The stock piper rear tailspring mount face is about 3/4" below the lower edge of the longeron or about 1" from the longeron centerline.

[Kodiakmack]

That’s odd. The spring I removed is a 1 1/4 spring of the same length as the stock spring from univair. Do I need a maule spring, and if so is it approved or more of a backcountry norm that gets by?

[Crash, Jr.]

YYeah, it does look like you would need a Maule tailspring. They are 1-3/4" in width but are designed to mount on a completely flat mounting point instead of the curved arrangement that Piper/Husky/literally everyone else uses. The Maules have a straight side on both ends with a 45 degree bend in the middle like the one you show. Legality is murky but point blank there isn't an STC or anything clear cut to put a Maule spring on a Piper. You will probably have to field approve it or use CAR3 regulation ambiguity to legally install it.

Others that are A&P/IA's on here maybe can chime in on how to do the paperwork to get it legal.

[mike mcs repair]

Did you try turning the spring parts around? Maybe they are stacked wrong?


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[mike mcs repair]

Individually ......


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[Kodiakmack]

They are from top to bottom short, middle, longest, with the middle spring having the elongated hole. It doesn't matter what order they go on since they all follow roughly the same shape.

[Kodiakmack]

I think I found the issue here.

The kit I bought off of Univair (Without really digging out part numbers because their site says "tail spring kit for PA-12") does not contain the part numbers called out for for the PA-12 in their catalog.... Found here https://www.univair.com/piper/piper-...el-spring-kit/

If I search the part numbers, I find a kit that implies by the name it's for a J3, but then also says it applies to multiple other piper models. The part numbers listed individually match those in the parts book, and appear to be the shape that the airplane wants. found here....
https://www.univair.com/piper/piper-...el-spring-set/

So, before going to the Maule spring I'll be returning the kit (thanks Univair for taking it back even though I already separated the springs), and getting the hopefully stock spring parts.

I would go to the Maule except for two things:
1. It's much more spendy.
2. With this old an airframe and the mission of the airplane, I'd rather have the weak point be the spring rather than transferring more into the bones of the old girl.

I'll post an update when I get the new springs.

[Crash, Jr.]

Interesting, I haven't seen that Univair spring set before. Definitely looks to have a curve similar to the Maule spring set.

Let us know how that works out; hopefully that's the fix

[Kodiakmack]

Digging deeper I’ve found that the springs that appear will work are for a hard rubber tailwheel and the springs I ordered that don’t fit are for a pneumatic tailwheel. Does anyone see a problem with mounting a 3200 to a set designed for a hard rubber tailwheel?

[Crash, Jr.]

Hard to say for sure but it should be fine as long as you use the correct adapter for your Scott tailwheel. I’m thinking the difference may be the angle of the bend. I think older Scott 2000s and Maule tailwhweels may have a different attach angle but that’s just a guess. Suppose you get to try it and share that info with the rest of us