C-85 Upgrade - What else while the plane is down?

[PA1195]

Well, hog or other beastwash aside it remains undetermined to me what the current STC holder's opinion and requirements are regarding SA1-210 with options "A" and "B" (https://dc65stc.blogspot.com/2018/12...explained.html). I have documentation and posted same in #29 that says changes are required to the fuel system. However the STC's lists and prints in my possession from Mr. Harer at the very least show otherwise.

The timing of the two pre-CAP STC sources is unclear. In my Post #29 Mr. Gilberti notes two sets of prints are available and the mod incorporating the C85-8 uses prints G-172, while using a C85-12 converts it to either a BC12D-4-85 (1280#GW) or a Model 19 (1500#GW) with prints G-171. The BC12D-85 and BC12D-4-85 are CAR4 airplanes and for Continentals are covered by TCDS A-696. The Model 19 is a CAR3 under TCDS 1A9. I suspect but cannot prove that the fuel cap and gauge issue arose when the Model 19 was added to the STC.

In the mix were the Factory, Jack Gilberti their engineer at one point, and the subsequent STC holders Gilberti and Harer that precedeTerry at CAP. An official determination remains the question, not opinions. I hope that's forthcoming for all concerned.

Gary

[astjp2]

The required modified fuel system for the C85 upgrade is technically a load of hogwash.

I installed the 85 upgrade (with the stroker mods) into my aircraft here in the UK (long before Mr Bowden became involved) over 10 years ago, and from a technical and fuel-flow perspective, there is no reason for all the silly fuel gauges and balance pipes and so on.

It was probably done to satisfy some 1950's CAA (or FAA) requirement back in Jack Gilberti's day.

I still use the normal 1946 fuel tanks and cork float on the front, but I did "nod a wink" to the 3/8 pipes from the wings to the fuselage tank (quite why, I don't recall...probably I got some cheaper while I was rebuilding)

My fuel flow to the carb was all that interested me, and in the hangar, with the tailwheel on the ground, and the main gear hoisted 12" off the floor, the gravity fuel flow was still more than 150% of the carb requirement.

I have a spare fuselage, motor mount, fuel tank and gascolator, I may try to run a test to see what attitude you lose the 4-6 inches of head pressure required by CAR4A. I used to have the number memorized, but that was 10 years ago. If someone has a forward fuselage they are willing to sell, I my try to do a good mockup with pictures. I have become pretty good at routing fuel lines. Tim

[PA1195]

Also recall the 3 gallon minimum fuel in the main tank per 1A9 NOTE 2. (h) for the Model 19 C85-12 and F-19 O-200: “Main tank usable fuel 9 gal.” (Must be displayed above the fuel selector valve). Perhaps the non-vented main cap and internal gauge plus forward pointing wing fuel vent(s) is in aid of that?

Gary

[astjp2]

The o-200 can out climb the fuel system, too high of an angle of attack, all the venting in the world cant help an uncovered fuel outlet.

[PA1195]

Head pressure can be improved by a combination of adequate fuel level and in-tank pressure above. That's how PA-18-180's were certified plus the extended vent opening stayed in the airflow above the wing at high AOA. Or so I was told years ago when I had them on my PA-12-180.

Gilberti supplied a required print that details modifying the existing Taylorcraft wing caps into a taller upward and forward pointing unit. Instead I have Atlee's for the same reason.

Gary

[N96337]

The thing I'm not seeing on any of your stuff, Gary is a date or any other official markings. Maybe this was Gilbertti on a bad day? Conversion of an aircraft via an STC doesn't matter a tinkers damn what reg it's look alike counterpart is certified under or what it's requirements are. We're not making a model 19, nor a BC12-85.... we're making a rough equivelant based on that airplane, the STC is the approval to deviate from that TC. It's not going to be a carbon copy, chances are. There is no data plate change, so it's forever a BC12 or whatever it started as, but can do the work of a later aircraft.
I'm still trying to wrap my head around what difference the vented cap would make on the main tank. Head pressure is head pressure, and vent pressure is vent pressure....I don't care how many vents you have, or where they're located. If anything, I'd say it'd have more chance of flowing with a vented cap as well down below. The only drawback is when you get to gawking out the window and overfill the main tank, and 100LL covers the windshield.
I sure do wish Terry would chime in!
John

[N96337]

Also recall the 3 gallon minimum fuel in the main tank per 1A9 NOTE 2. (h) for the Model 19 C85-12 and F-19 O-200: “Main tank usable fuel 9 gal.” (Must be displayed above the fuel selector valve). Perhaps the non-vented main cap and internal gauge plus forward pointing wing fuel vent(s) is in aid of that?

Gary

That has nothing at all to do with the converted aircraft. They don't have to conform to that, just to whatever the STC says.
John

[PA1195]

Yup John I agree on the lack of official documentation of Gilberti's response above in Post #29. However it was included in the Foundation link I mentioned. He signs the first page as "Gilberti Aviation" and the second as "Taylorcraft, Inc. Jack Gilberti Engineer" so the reply may be a composite written over time. Don't know that and who supplied it. It is a signed document but without a date and Notary, but with some validity unless proven otherwise.

I choose to run an Atlee vented main tank cap and two of their tall vented wing caps. The fuel gauge and vent is as described in my earlier post and pictures. Atlee Dodge modified the tank for the previous owner I assume per the prints I posted and have on file.

The TCDS 1A9 fuel minimum is real for the Model 19 C85 and F-19 O-200 per CAR3. How equivalent owners choose to deal with it is their business. A local had an engine burp/stoppage on the ground taxiing with 29" tires then later in a climb with minimum fuel so take that as an actual event. Converting a BC12D to the equivalent of a Model 19 at 1500# GW does require a CAR3 Flight Manual and associated placards according to Terry.

But again, all this is speculation. Do I (who has the Model 19 and F-19 tank and vent configuration and is not concerned) have to call Terry Bowden and engage him for others who may be in denial? He has been very supportive in the past and gave me clear instructions on how to convert mine via paperwork to 1500# Model 19 if later desired. I respectfully suggest if someone truly gives a shit about their work and fuel systems that they call and request clarification. Given that Terry is a DER he can probably resolve any existing or future concerns.

Gary

[PA1195]

I guess another question for Terry Bowden CAP might be:

How many versions of the STC SA1-210 paperwork were made available?
Do they vary in content...prints and lists of required parts for example?
What records does he have regarding Gilberti's paperwork and items like the letter's contents in #29?
What's the basis for Gilberti's letter in Post #29 and list of equipment that appears to vary from prints and lists owners may have used? Is it approved data?
What did Harer do besides sell the STC?
Today what prints and lists apply and are available from CAP?
Can deviations to the STC be approved, and of so at what cost and in what form?

There may be more. I'm more curious than some but still hope there's a reasonable explanation for any changes or discrepancies. Any C85 upgrade should clearly follow CAP's data if that's the version used.

EDIT: Stu I apologize for all the discussion regarding the C85 STC. It tends to happen as in a friendly conversation among pilots. Do you have the STC for your S/N yet and if so who supplied it? That may clear up all this speculation.

Gary

[N96337]

Yeah, it'd be interesting to see just what is out there! I went through this with another old STC that had been updated, and even if you don't have the most current update, as long as your aircraft is in compliance with the STC as it read when it was intstalled, it's ok.....at least that's what our FSDO said.
I'm sure any STC can be deviated from....IF you can find a fed that will sign off on the deviation. I know I've had quite a few deviate on my aux fuel tank STC for Stinsons, installing different fuel fillers, etc. I think as long as it's not a major deviation, they usually don't mind.
I'm sure the minimum fuel data is real for the 19, but technically this never can be a 19, even when modified exactly like one, so maybe that's how they got away without that requirement? When I did my fuel tank STC, I figured we'd have to pull baggage as we added fuel, but the DER said no, so you can still have the 100# of baggage and fill the 13 gallon tanks, as long as you don't exceed gross weight or out of the CG envelope. HIs reasoning was that he felt the baggage structure was strong enough to support both at the same time.
Bill Berle (Victor Bravo) was having problems with his fuel tank unporting too, if I remember. I've got a dual port fuel feed drawn up for mine, and it will be installed when the aircraft goes back together. Just makes sense to me. Like Tim said, the O-200 can outclimb the fuel system and that's not a good situation, even for a minute!
I'm friends with Terry on Faceplant, so I'll see if he will come on over and enlighten us!
John

[PA1195]

John thanks for the obs especially re your own STC experience. Terry has been very helpful and as a DER can broad jump the FAA and support major alterations via deviations to STC's for instance. Examples: https://app.box.com/s/ikk8yaw0astcr03j8fafl25t4fnywu23

Another good read on STC SA1-210 explained: https://dc65stc.blogspot.com/2018/12...explained.html

Here he addresses prior applications of the STC: https://app.box.com/s/kqrjevbzv6

Note especially under #2 above: "...C.A.P. will provide duplicate copies of the STC and drawings that were in effect at the time your airplane was modified." Which leads me to believe the STC evolved over time due to changes in approved data.

So good maybe a friendly enlightenment is due and Stu can resume his project in peace.

A local that now owns one of Victor Bravo's Taylorcrafts is the one that had the unporting issue. May be the same plane.

Gary

[PA1195]

As far as engine stoppage due apparent unporting of the main tank's outlet or lack of flow to the carb....in addition to minimum fuel limits consider cleaning all filters between the tanks and carb plus air vent inlet(s) to the tanks. Any restriction to fuel flow is a problem waiting to happen.

I cleaned my inlet air vents of spider webs and captured bugs. I flushed the wing tanks and their finger screens via throughput of fuel out the open drains...lots of bugs and debris recovered, I drained the main tank then washed and later siphoned off any debris observed through the filler neck. Removing the outlet valve and cleaning the screen would do the same. The gascolator gets serviced by mechanics as well as the inlet screen to carb.

After 78 years and thousands of hours the fuel system collects lots of stuff that can restrict flow.

Gary

[astjp2]

As far as engine stoppage due apparent unporting of the main tank's outlet or lack of flow to the carb....in addition to minimum fuel limits consider cleaning all filters between the tanks and carb plus air vent inlet(s) to the tanks. Any restriction to fuel flow is a problem waiting to happen.

I cleaned my inlet air vents of spider webs and captured bugs. I flushed the wing tanks and their finger screens via throughput of fuel out the open drains...lots of bugs and debris recovered, I drained the main tank then washed and later siphoned off any debris observed through the filler neck. Removing the outlet valve and cleaning the screen would do the same. The gascolator gets serviced by mechanics as well as the inlet screen to carb.

After 78 years and thousands of hours the fuel system collects lots of stuff that can restrict flow.

Gary

Gary, most of that should have been cleaned out during the last recover...and a lot of us hangar our airplanes. Tim

[PA1195]

Finding a good mechanic Tim is a challenge. I hope Stu has help and advice for his engine.

Gary

[PA1195]

I expect Terry of CAP will be here soon with information regarding our internal discussion. Facebook tells me this I know.....

Gary