BC 12 D with short mount C-85

[flyguy]

Re: BC 12 D with short mount C-85

Gary,
My 337 for an 85 conversion is so weird that I am hesitant to supply it to anyone for use. I have confirmed that it is good with the FAA, but I don't want to push it. (rule #1, keep a low profile.) It is for a 85 on a short mount, no electical, no starter. Here is the weird part: the airplane is not a real -85 though. There were no changes to the fittings of any kind, so the plane is really a BC12D-65 with an 85 engine. It is registered as a -85, but the allowable gross is 1200, not 1280, even though it has the extra vent lines, and 2 tanks, ect. If you cannot not find anyone with a "normal" 337 to use I may reconsider my position at a later date. Since the previous owner tried to make it into an airliner with a nice installed radio, -25 battery, lights, strobe, copper fuel lines, big tires, heavy pneumatic tailwheel, ect., I can only have a passenger of less than 120 lbs. and only with 12 gal. in the center tank.
Darryl

[Gary Snell]

Re: BC 12 D with short mount C-85

Thanks Darryl. I would agree that your 337 would not be ideal for me since I would prefer the full conversion with the GW increase. Hopefully, someone else has what I need.

Gary

[Don Eide]

Re: BC 12 D with short mount C-85

Gary,

I would definitely use the Harer STC. It's the only way to go.
I don't see any problems with it and only a few minor discrepancies, which if you study the Drawings, are no problem at all. With an STC your IA can sign it all off. Getting a 337 approved, your working with the Feds, not fun here.
Maybe if your Feds are married to your sister they are a little easier to work with.

The Model BC12D-85 is (same as a BC12-D except for increase power and gross weight, fuel system changes, auxiliary wing fuel tank, revised wing fittings and minor structural changes)

Power: Continental C85-8F
Gross Wt: 1280 (how do you get that on a 337?)
Fuel system: 12 Gal main and at least one wing tank is required,
Second wing tank optional.
Revised wing fittings: heavier and reinforced, and larger bushings.
Minor structural changes: Front spar reinforcing plate as plainly
shown on the STC.

Now with a LOT of work you can have either a BC12D-4-85 with a gross wt.
of 1280 or a Model 19 with a gross wt of 1500.

Your choice,

Don

[VictorBravo]

Re: BC 12 D with short mount C-85

<< snip>>
Minor structural changes: Front spar reinforcing plate as plainly
shown on the STC.

Hee hee hee.... Naahhhh, I couldn't

Merry Christmas, Don

[Gary Snell]

Re: BC 12 D with short mount C-85

Thanks Don for another perspective. So it sounds like the STC gives you the option to pick whichever model you're converting to......BC12D-85, BC12D-4-85 or F19. Is this a correct statement? I think I now have a pretty good understanding of the changes involved with the wing fittiings, but was not clear if there are any changes at the attachment points on the fuselage. Any mods/welding at the front/rear fittings?

[Don Eide]

Re: BC 12 D with short mount C-85

Gary,

You are correct. The STC covers all three models. Pick the one you want.
There is NO welding done on the fuselage at the attach points. All the beef-up is done on the spar straps. The front strap is made out of 4130 x .095 with a "U" part of 4130 x .049 welding the two straps together and the rear strap is made out of 4130 x .065 also welded with a "U".
My T-craft already had these. NO I don't know why, but probably because my T-craft was destroyed and rebuilt many years ago. I'm amazed they rebuilt it.

Don

[Gary Snell]

Re: BC 12 D with short mount C-85

Thanks Don...all is clear to me now. Maybe I'll get lucky with my wings having the changes already done. The wings are naked now so I'm heading out to the shop to see what I have.

[Don Eide]

Re: BC 12 D with short mount C-85

Bill,

For some unknown reason you got hung-up, lost, waaaaaay out in left field, or whatever words you want to use, on two little words in the entire STC.
"No Changes", and they were correct when Gilberti did the STC. NO, I don't know why his T-craft already had the front spar reinforcing plates on, but they had to be there because they are plainly shown on the STC.

Question for you Bill. Did you follow the STC on Drawing G-110 (Strut fitting Front Spar) where the dimension is 1 1/16 between the fittings?
If so, how do you do it without the front spar reinforcing plate?
My spar is 3/4" thick, two 1/8" plywood doublers and two 1/32" reinforcing plates makes 1 1/16" thick spar.

Don

PS. I can't print what my IA said about you when you called the front spar reinforcing plate "Mystery Lines" when they are plainly shown on the front and top view.

[Jim Herpst]

Re: BC 12 D with short mount C-85

Think that one has been discussed enough. Lets not attemp to re-open old wounds and instead end the year agreeing that we have the best Damn planes in existance. Thank you CG Taylor and the folks form Alliance for getting behind the company to begin with.

Now I discoved a weird situation with relation to spars. I have a set of wings that have NO plates at the root end of the wing. They just installed the bushings. Period. !! I have no idea if or when these spars were replaced . They are out of a 1940 BL. Go figure. Of course the spars are cracked... all of em .... all cracks run fom the first compression tube to the root end.

[Don Eide]

Re: BC 12 D with short mount C-85

Okay. I'm done.
Goodby.





Don

[VictorBravo]

Re: BC 12 D with short mount C-85

For some unknown reason you got hung-up, lost, waaaaaay out in left field, or whatever words you want to use, on two little words in the entire STC.
"No Changes",
PS. I can't print what my IA said about you when you called the front spar reinforcing plate "Mystery Lines" when they are plainly shown on the front and top view.

That is the mystery exactly, Don. The STC says two different conflicting things, depending on which part of it you're looking at. I got hung up on two words, and you got hung up on two ink lines...which one of us is any crazier than the other? Worse yet, the STC does not give you any information to help answer the questions it created. So it's open for interpretation, and you did it one way and I did it another way. Neither one of our airplanes will crash because of this part either.

You have a drawing that you sent me (thanks sincerely), showing this part clearly. The STC drawing also shows the outline of the part, with no argument from me. But Taylorcraft built thousands of airplanes without that part, some of which are FAA certified to 1500 pounds.

You make these huge, un-founded assumptions that Jack Gilberti was thinking this or that on the day he wrote the STC, or un-founded assumptions about which specific airplane he used as the basis for the STC and if it already had this part installed, but there is no documentation on ANY of it, which makes the confusion even worse.

WHERE is the documentation of what Jack Gilberti was thinking, which airplane he had in mind as the basis for the STC, and which airplanes use part 2569 and which do not?

WHY ARE YOU THE ONLY ONE WHO SEEMS TO HAVE THIS DRAWING?????????

The Gilberti/Harer STC does NOT include this drawing or any call-out of this part, but it DOES mention every other little tiny part you could imagine and has a drawing for it. It is unlikely that they would have mistakenly omitted the drawing, especially since the drawing existed as early as 1947. So if drawing 2569 is not included in the STC, and your airplane does not already have it installed, and there is no instruction ANYWHERE in the STC that tells you to put it in when doing the upgrade, then it is illegal to put it in without an engineering basis to do so. That makes as much sense as anything else, but it sure raises some questions.

I asked you, and your IA a question and still have not gotten a reply from either one of you (or the Foundation, or Harer, or the ghost of Jack Gilberti, or Gengis Khan)... The 1951 Model 19 owned by Grant Bailey is factory certified to 1500 pounds gross weight, left the factory without these extra plywood doublers, and was issued a type certificate... is this a safe and certified airplane or not...yes or no?

I would like an answer from your IA, was and is the 1951 Model 19 a safe airplane when flown at 1500 pounds, yes or no? Why has nobody in a position of authority addressed this, and offered an explanation that might affect all other T-craft owners doing these modifications?

If this is not a mystery, then neither is Amelia Earhart.

Please post your IA's answer to my question here in public... I can take whatever he says about me

Anyone else in a position to know is free to answer this question as well... is the 1951 Model 19 (factory built without part number 2569 installed) a safe and certified airplane when flown at 1500 pounds or not?

Sorry Jim, I apologize for taking the bait once again, but maybe we should end the year by setting a precedent to actually fulfill the charter and main puspose of the Foundation, and to ferret out the truth for the benefit of air safety and the education of Taylorcraft owners. If this were a 60 year old fabric covered Piper product, someone could have called Clyde Smith 6 months ago and he would have solved the mystery within a week, whether it was a factory goof or an STC goof or whether it was one guy mis-interpreting the STC.

Happy New Year everyone, sorry for ranting...

Bill

[crispy critter]

Re: BC 12 D with short mount C-85

Here it is fellas, sorry I didn't catch on to what you guys were talking about sooner.
The BC12D-85,19,and model 19(long mount C85-12-1500lbs gross) did not have the extra(thin) doubler. The F-19(long mount 0200-also with 1500lbs gross) starting in the early 1970's did have it, making a total spar width at the front strut fitting 1 1/16" think.

[tcraft]

Re: BC 12 D with short mount C-85

Don has asked that his registration and membership with the Forum be deleted which I have just completed. Perhaps some of you will think about what caused him to leave our community.
Bob.

[VictorBravo]

Re: BC 12 D with short mount C-85

Don has asked that his registration and membership with the Forum be deleted which I have just completed. Perhaps some of you will think about what caused him to leave our community.
Bob.

If he is willing to come back, please send him my apology and my offer to "take his place" as the one being deleted.

I had and have no intent of driving anyone off of a group like this. I consider all of you friends and fellow enthusiasts.

I didn't know that this debate had become a personal affront to Don, and that anyone was feeling that strongly that they were under attack personally. It was SINCERELY just a spirited debate to me, for what I see as a really good cause. In any good legal battle, the attorneys attack each other's viewpoints, politics, or interpretations, but they are not attacking each other.

It appears that I am more concerned with solving an interesting mystery than most of the people here are. I'm sorry if any of you wanted this to be a genteel social organization and I turned it into an unwanted investigation into something unimportant to most of you.

Kevin, thank you for doing what nobody else has done... coming up with at least a partial answer. Thanks to you, anyone who is actually interested in this issue can make a more informed decision, with fewer questions raised.

Bob, contact Don and tell him I sincerely offer to go instead of him. I feel awful that anyone was made to feel that way (rightly OR wrongly) because I was trying to make a point too forcefully.

Bill Berle

[Acroeric]

Re: BC 12 D with short mount C-85

Kevin- You are correct about the extra plywood plate on the F series- I just aquired a set of NOS spars and that was the first thing I noticed. I will be glad to take a few photos and post them if anyone is interested. Also- I am pretty sure the drawings Don mentions are present in my STC paperwork- I have an entire package of engineering studies for the 0-200 installation as well. This stuff came with the project- who kows how it got there.

With regard to the 337 for the C85.. .. .with the new 8300.10 Volume 2 chapter 1 (our guidance on what we can field approve) we are limited to a 10% HP increase. To go higher we have to get engineering approval from the ACO or you have to apply for a one time STC. Bottom line- spend the $250 and save yourself some time.

Maybe someone could talk Harry into making a retrofit kit and supplying instructions for the conversion- Manufacturer supplied data is approved- therefore it could be done w/out FAA approval every time.