Franklin Engine 6A-350-C1

[MauleMedic]

Hello All,
I'm getting ready to pull the vibration dampener / accessory drive pulley off of a Franklin 6A-350-C1 engine from a 1974 Maule M5-220C that I'm rebuilding after its fourth wreck...(and four aircraft registration number's too mind you). First "N" one in U.S. - then a "C" after it moved to Canada after a ground loop wreck in AK then back to an "N" after being rebuilt from a freshwater drowning as a floatplane in Canada...then the previous owners switched it to its fourth - another "N"!

So far I've done:
Spar rework on the wings / reskinning some panels / a few new ribs, etc.
Reskinned flaps
Ailerons
Replaced some fuselage tubes
Installed the super skylight kit
Got new sealed wing lift struts
Right landing gear assy / oleo
Recovered with PolyFiber / Aerothane paint

It has tip tanks, Scott TW, rear sling seat, etc.

But now it's the engine...
when I acquired the project the previous owner bought new mags / had the carb rebuilt / new engine mount...etc after the accident. So I'd really like to overhaul the Franklin because that would be more cost effective for me than to try a field approval for putting in a 540, 360, etc and all the associated changes.

So I'm looking at pulling this dampener / drive gear off in the next couple of weeks (after final exams when I have some time) so I can split the engine case and start the overhaul. It's a press / shrink fit and I'm expecting that I'll have to make up special tooling for the removal. But just wondering if anyone has experience or any general advise that will make me the wiser.

PS I'm also looking at getting a serviceable McCauley prop. (it's the "dreaded threaded" style). The one I have is too far gone due to the landing gear folding in, catching the wing (bent spar) and bending the prop. - blades are beyond repairable limits.

There is a possibility of getting a new prop. cutting it to fit an STC for a Franklin 6A-350 on a Swift (if memory serves me right) and then hoping a field approval would work. But I'd prefer to find a used one that's certified for the Maule.

I'm open to all suggestions - and anything else I should consider modifying / upgrading at this point.

Things I've considered:
Tire size increase
Patroller doors
VG's (do these really make a difference) I'd like to add them before I shoot my leading edge paint
Gap seals
...any other suggestions

[a64pilot]

Can't help you with the Franklin, Sorry. Absolutely do the patroller doors though.

[Karl Hartlen]

VG's,,,, definitely. You will not regret it!!

Karl

[MauleWacko]

[xwildcat]

The biggest improvement I've seen in the very short while I've owned my M4-220C is the elevator gap seals. I've installed VGs and like them. I'm getting new HD gear (my left main is bent) and bushwheels. However, the gap seals really changed the plane. I love them. I also like my patroller doors more than I thought I would, but I wouldn't take for my new gap seals... FWIW.

[MauleMedic]

Hello Everyone,
Thanks so much for the wonderful response. It is really encouraging.

I just looked up the TCDS (Type Certificate Data Sheet) for the Maule M5-220C #3A23 (covers most Maule models).

According to the sheet I can only use the McCauley 2A34C22-N S84SF-6 or -8 with 78 in. max and 74.5 in. min. on the diameter.

The M4-220, C, T, etc. is not as strict and actually can use some other props as well.

So, in short, I would really prefer one of the above two props - otherwise I am looking at needing an STC (for which there is not one that I am aware of)...or trying to get a field approval.

Thanks again for all the above suggestions - I really do appreciate it!

[a64pilot]

David Wright got a prop STC either for the 210 or 220, not sure which. You should contact him.

[MauleWacko]

[Karl Hartlen]

The McCauley C201 prop is certified up 88" for the 220 franklin engine. There is data to use it on your M5. I have all the load test and clearence data to use an 82" running 850x6 tires on the Maule. It is well worth the effort to get it done for the performance you will gain and ease for finding parts for the C22 down the road. I did not need an stc to use it. A field approval is simple if you provide the feds with all the paper work so it is spelled out in black and white in front of them. Asking to change something or do something that has no documents is where it gets complicated.

I would be very interested in knowing if this 82" prop would legally fit on my M4-210C? Would anybody know if it is possible?

Karl

[MauleWacko]

[Karl Hartlen]

No. It is cert. for the 220 franklin engine and some 0-470 engines in the Cessna's. The IO-360 has had to find and big $$ props.

Do you mean that props for th IO360 are expensive and hard to find?

The reason I was asking is; last spring I was discussing with another M4-210C owner, who said he put the prop off a 172XP on his M4. Apparently the M4 now performs surprizingly well

I am just looking for ways (legal) of improving my M4's performances. The 172XP trick I mentionned above, was not too legal according to this guy. He figured both machines use the Cont. IO360,,,,,why not the prop

Karl

[MauleWacko]

[MauleMedic]

Thanks all for the information and help...I'm certainly going engine first and then will be looking for a prop. once everything is up and up.

As for the engine I ended up machining / fabricating a lot of the specialty tools listed in the maint. manual because they couldn't be located elsewhere. I had been warned that certain rear-end gears would be hard to remove and that I would hate the minute I started the job...but was pleasantly surprised that everything cooperated just fine and it has been one of the simplest engine teardowns to date.

If other's are getting ready to overhaul your Franklin send me a message so I can send you info / drawings for the tools - I'm sure they'll save you tons of time or broken parts.

Once again,
Thanks

[xwildcat]

If other's are getting ready to overhaul your Franklin send me a message so I can send you info / drawings for the tools - I'm sure they'll save you tons of time or broken parts.

I sent you a PM.