Pre-war wing on model 19!!

[crispy critter]

I have a friend that just purchased a BC12D that has recently been converted to a model 19 with 85hp,long mount,complete electrical system,extended baggage,etc,etc. using the Gilbert/Harer STC.All the paper work and data tag say it started life as a 1946 BC12D and all the fuslage fixtures support all the paper work but it has pre-war,truss built,13 rib,steel tubing aileron hinged wings.I know by text book regulations that it is not really legal to use an old design on a newer aircraft.I.E. It is perfectly legal to put post war wings on a pre-war airplane because no changes or mods have to be done,it is simply an upgraded bolt on improvement that changes nothing except the quality of the aircraft.I guess on this one you could say that the fuslage and tail was changed along with the paper work but I don't know if that could be accepted as a legal loop hole.Here is my question,is it legal to use these pre-war wings with the model 19 conversion???Also,what is the gross weight on the pre-war t-crafts,I think it is 1150 or 1180 ain't it?

[Robert Lees]

Re: Pre-war wing on model 19!!

If the plane is legally a B model (dataplate, cert of airwortiness, etc), then yes, legally you can do the mods.

[Jim Herpst]

Re: Pre-war wing on model 19!!

The wings are for 1150 Gross. I doubt with an electrical system on a BC12D "upgraded" to a model 19 he is at an empty weight that makes these wings safe(margin of error ...SAFE ) on this plane . He has some REAL issues in my opinion. I will purchase his wings if he decides to deal with this issue. I can use them on another 1940 project that I have. I am not saying he has problems just cause I can use em eithor. Now I will sit back and see the comments on THIS one !
Be good yaall
JIM

[Robert Lees]

Re: Pre-war wing on model 19!!

I believe the question was one of legallity, not of engineering

[VictorBravo]

Re: Pre-war wing on model 19!!

From my recent and ongoing research, it APPEARS that the wing spars on a pre-war B model and a post war B model are the same. Even as far as the "model 19".

As such, if you put the big bushings in the spar root, weld the strut fittings, and the other Harer mods, according to the STC you should have the same 1500 pound safe weight as any other B model.

Bill

[Jim Herpst]

Re: Pre-war wing on model 19!!

Ok Round two. The pre war uses a 13 rib wing. SOO it would appear that with the other Harer mods made to the wing as Bill outlined it does not matter a rats rear end about it being a 13 rib wing vs a 15 rear wing as in the later models. After all the Harer STC is approved for the BC-65 planes (Not the BL-65 mind you...... same plane but I throw that out to remind the unknowing....) ANYWAY not to get off track it would appear that LEGALLY (according to our resident Brit) and engineering wise (according to Bill )that we are ok to go up to 1500lbs with this completed STC... on a pre war OR on a BC12D WITH PREWAR Wings. And no the Truss type ribs matter not either I suppose.. I bet they are almost as strong any way .. just lighter.

I only remember being in rough air FULLY loaded with ol 94984 . It was a standard BC12D . Personally It would make me nervous in this situation with a pre war wing with even yet MORE Load. Guess I could over come this too with time........

Flame on
By Yall

[Robert Lees]

Re: Pre-war wing on model 19!!

I agree with Jim.

To quote the STC, it says:
"Conversion of Taylorcraft Model BC or model BC12D to the equivalent of the following aircraft models:
Model BC12D85 .....Model BC12D-4-85 or Model 19....."

The BC model was created in 1938 (with 13 ribs). The STC allows conversion of this model, so if the documentation, dataplate & logs shows it as one of the above models, and shows compliance with the STC, it is legal. An AI would have verified the documentation during the pre-purchase.

From an engineering perspective, Gilberti (the STC designer) intended the STC to be applicable to the 1938 BC 13-rib model. He was no fool.

[flyguy]

Re: Pre-war wing on model 19!!

I had a BC12D that was built in December of 45 that had truss type ribs. There was no record of the wings being damaged or changed. (yeah, I know) I always assumed they just used the leftover wings and parts when the line started back up in late 45. I didn't know that there was anything unusual about the wings because it was my first Tcart, so I never counted the ribs. It was really light and would climb like a monkey.
Darryl

[Jim Herpst]

Re: Pre-war wing on model 19!!

It probably had 15 ribs of the built up type. I believe all or most of the 45s did. They were lighter for many reasons like the wings and fabric doors

[Acroeric]

Re: Pre-war wing on model 19!!

Folks- I thought all the BC series and up aircraft had 15 rib wings. I know the 38 BL had only 13.

In the manual it lists the ribs as being interchangable- I plan to use all old style built up ribs in my '46 restoration because I have a good set.. . .I also will be using the old steel aileron hinges as they resist corrosion better than magnesium over the years. There are many interchangeable parts between a pre and post war- (like vert stab and rudder).

[crispy critter]

Re: Pre-war wing on model 19!!

Eric,
The vertical stab and rudder are only interchangable from pre-war to post-war if you change them both.

[Jim Herpst]

Re: Pre-war wing on model 19!!

Crispy, No flame to you intended. I believe Eric understands this. His point was that you canput the later on the former and visa versa... of course as a matched set. (He has had several clipped wings the last of which was a Swick ) and if one looks at the plans you will see the suggested rudder is the height of the late model but has the "bottom outer gut" of an early model with the early model threee hinge set up.

[Acroeric]

Re: Pre-war wing on model 19!!

Yep- I guess it would be a little difficult to attach a 2 hinge post war rudder to a 3 hinge pre war vert. stab;-) Also- In my earlier post I meant to say that I thought all BC-12 series airplanes were 15 rib designs. . . . . . If I were to have a model 19 conversion I sure would want the extra ribs. . . . . 13 just doesn't pass the eyeball test.