Another pre-war wing question

[ajfriz]

I've been searching on the forum quite a bit, but I haven't found the answers to my questions.

I have a 1940 BC-65 that I recently purchased and it's completely disassembled, so now is the time to do all of the mods to the airframe and wings. I'm planning on installing a c-85 stroker which got me thinking about the wings. My wings are the pre-war 13 rib units and I'm trying to find out if they are significantly weaker than the 15 rib wings.

I've heard that you can pretty much bolt on the post-war wings to a pre-war fuselage and still keep it legal, which makes me think that if they are indeed stronger then I might want to do it since I'm planning on upping the gross weight. Is this worth doing? Is it ok to "convert" my wings to the 15 rib style by adding a couple more built up ribs?

I'm not too worried about keeping it original (which I'm sure will not sit well with a lot of the pre-war purists). I just want to make this into a safe airplane with enough power to operate safely at gross out of an airfield that is 5,000' ASL.

AJ

[Ragwing nut]

Re: Another pre-war wing question

41 deluxe and 45 have 15 built up ribs and higher gross weight of 1200 lbs. I have converted several. PIA but it is better than heavier postwar wings

[crispy critter]

Re: Another pre-war wing question

I think you can legally go to 1200 with the 13 rib wing but if your wanting to convert to BC12D-85(1280 gross),Model 19 or F19(1400+ gross) then you can not do it with the 13 rib wing. If fact you might want to read the STC very carefully because I believe a lot or all of the pre-war birds might not be included in the STC for the 1400 gross increase. I might be wrong but just make sure you read it close. I know there have been several pre-war models converted using the STC but just look at it closely.

[ajfriz]

Re: Another pre-war wing question

I thought that I was reading somewhere on here about a guy that had a pre-war that was 1500 lb gross. I could be wrong though.

I'm wanting to increase to at least 1280 because it is going to have an electrical system along with larger tires. My plan is to push the gross, power, and fuel as close as I can to the LSA requirements so that I will have the ultimate LSA. For me it doesn't need to stay LSA compliant, but I feel that the value will take a big hit if it isn't.

[crispy critter]

Re: Another pre-war wing question

When I finally got my ONE time STC approval to install the 0200 on Crispy with a wt increase to 1280(same as the BC12D-85) I also wanted to increase the gross wt to 1320 or somewhere close without going over and they said it would not be so easy,man they wasn't kindin either. I did follow up on the requirments and they were going to cost a fortune, and there was going to be so much red tape and testing that it simply wasn't worth it at the time. I was going to have to submit everything to the FSDO's engineering dept of choice,then pay them lots of money to research it,then I would have to do a series of documented test flights(which I didn't mind). There would be several inspections by an FAA engineer at my expense and before I could take it any further then a "ONE TIME STC" I would have to submit load tests done in the presents of an FAA engineer or offical guy of some kind....meaning I would have to load down a t-craft airframe until it broke with the same mods I done to mine and it would have to hold an X amount of wt at certin points to pass. I don't remember what the exact details were but it was going to be a nightmare to get it done. I would still like to do it someday but right now I would just like to get back into a postion to get Crispy back in the air again.

[Jim Herpst]

Re: Another pre-war wing question

Two words. Go Experimental. Oh boy all about Liability I suppose on the Airworthness orginally "granted" by the CAA/FAA. Seems though that common sence would play when one looks at BC12 D Sea planes, The F-19 and all the Data ALREADY THERE. Thats the FAA. Thats where we are . Perhaps they have always been the same even back in the CAA days. Thats a big bone to me too Kevin.

[freightpilot27]

Re: Another pre-war wing question

We also have a goal of a certified Tcraft with 1320 lb gross wt.
In my eyes, it shouldn't be difficult, with the C-85 STC option of 1500lb gross weight, just do the mods and limit the gross to 1320. All the structural load stuff is done and approved to 1500 lb. Stupid simple to me, but we ARE dealing with the FAA here and I know how simple it won't be.
Mine will be 1280 with the 1500 lb mods and i'll fly it at weights of up to 1500 lbs. i know it will handle it.

Yes, I know legality issues. But this is my plane, my name in the logs, I rebuilt it. i know it inside and out, no one else will be flying it or maintaining it, yadda, yadda, yadda.

I'm NOT recommending or suggesting this for anyone else!

Besides, it will be a while before its flying and maybe the 1320 lb gross will be available by then- Terry Bowden?????

[crispy critter]

Re: Another pre-war wing question

We also have a goal of a certified Tcraft with 1320 lb gross wt.
In my eyes, it shouldn't be difficult, with the C-85 STC option of 1500lb gross weight, just do the mods and limit the gross to 1320. All the structural load stuff is done and approved to 1500 lb. Stupid simple to me, but we ARE dealing with the FAA here and I know how simple it won't be.
Mine will be 1280 with the 1500 lb mods and i'll fly it at weights of up to 1500 lbs. i know it will handle it.

Yes, I know legality issues. But this is my plane, my name in the logs, I rebuilt it. i know it inside and out, no one else will be flying it or maintaining it, yadda, yadda, yadda.

I'm NOT recommending or suggesting this for anyone else!

Besides, it will be a while before its flying and maybe the 1320 lb gross will be available by then- Terry Bowden?????

Something else you need to consider,the 1400-1500 gross wt also includes the addition of the large baggage compartment,longer engine mount & cowling,big battery located int eh aft section or behind the big baggage compartment,and original style starter & generator up front,more & heavier insturments,radios,etc. which makes up for that 1500lbs. increase. By the time you figure all this stuff in you really don't gain any extra useful load at all,in fact you might loose some,lol. You also need to consider that doing this on the short mount like I have done,you really don't want to add the large baggage compartment or put the battery too far back. I have not changed the CG at all or added any notciable weight to the airplane with the mods I have done. You don't want to make a BC12D into a F19 with the short mount and try to load down a large baggage compartment. So there is some reasons why the FAA is tough on these things but we could work it out if they would make it possible for us at a reasonable cost.

[freightpilot27]

Re: Another pre-war wing question

We understand the weight penaltys involved with the modifications and extra equipment of the CAP C-85 STC. We are following the STC for the conversion to the Model 19, but keeping the lower gross weight on the paperwork.
I have done extensive and detailed CG and empty weight calculations with every modification, change and equipment installation. Albeit all based on the original empty weight calculations of the plane from the factory (it was never an updated weight and balance performed). I understand these will change as the build progresses. Estimation of new empty weight will be between 815lb - 825lb.
Long mount
C-85 w/O-200 mods
Stainless Luscombe exhaust
McCauley metal propeller
light weight alternator
Light weight Starter
Odysee battery (final location to be used to adjust empty CG)
Nomex Honeycomb large baggage panels
24gal fuel
Skylight
single landing light
3 point strobe system
Becker Comm & transponder, etc
ELT
minimal interior
polyfiber fabric
required structural repairs & modifications

[N96337]

Re: Another pre-war wing question

Two words. Go Experimental.

Jim, that would be awesome...but it aint gonna happen now a days with the FAA.....
John

[crispy critter]

Re: Another pre-war wing question

We understand the weight penaltys involved with the modifications and extra equipment of the CAP C-85 STC. We are following the STC for the conversion to the Model 19, but keeping the lower gross weight on the paperwork.
I have done extensive and detailed CG and empty weight calculations with every modification, change and equipment installation. Albeit all based on the original empty weight calculations of the plane from the factory (it was never an updated weight and balance performed). I understand these will change as the build progresses. Estimation of new empty weight will be between 815lb - 825lb.
Long mount
C-85 w/O-200 mods
Stainless Luscombe exhaust
McCauley metal propeller
light weight alternator
Light weight Starter
Odysee battery (final location to be used to adjust empty CG)
Nomex Honeycomb large baggage panels
24gal fuel
Skylight
single landing light
3 point strobe system
Becker Comm & transponder, etc
ELT
minimal interior
polyfiber fabric
required structural repairs & modifications

Unless you redesign the wheel the feds won't let ya do all that and stay at 1280.....I tried for almost a year to do all the mods while keeping the gross at 1280 and with the starter,alt,& long mount,with or without the extended baggage they would not let me do it. That's when I finally gave up and asked if I could do the 85 conversion(BC12D-85) and they had no problem with that as long as I follow the factory drawings for the mods and notifiy them with any changes. Then I ask if I could bump that up to the 0200. At first they said no,then out of the blue one of the FSDO inspectors called me back and asked for more info about that before they reviewed it. He said he would not personally approve it because his boss wouldn't let him, but if I could find a DAR or an FAA employeed engineer who would back me on it then they would be more incline to let it go through without so much grief. So my dad told me to track down an old friend of his who used to be a local IA and DAR with an engineering degree. When I finally tracked him down it turns out that he was then employeed as an FAA field inspector out of Cincy,lol....that made the approval much easier. I still had to do things by the book but he helped me read/re-write the book as we went along,lol. We did every airframe modification straight off the factory F19 drawings leaving the short mount and baggage compartment stock. The plan was to get all this done and get the airplane flying, then do the approval and install the light wt starter & alt systems from B&C, but before I could get Crispy flying my inspector had a heart attack. After a couple surgerys and a year off he decided to retire so that's as far as I got. Because of a goof up in the orginal paper work we had to draft the help of another DAR to get our prop and exhaust approved(thanks Terry). I'm still hoping to get the starter & alt approval but that's not important until the airplane is flying again. I would eventually like to try to either get or use my airplane to help someone get an STC approved for these mods so everyone can use them. I would also like to see it with a 1320 gross wt.....maybe someday

[freightpilot27]

Re: Another pre-war wing question

Redesign the wheel? I don't follow.
I'm just following one option of the current C-85 STC. Without upping the weight. (my mistake in an earlier post- The gross will stay at 1200lb not 1280lb)

[ajfriz]

Re: Another pre-war wing question

I have been tempted to just go experimental and use an 0-320 and a highly modified slotted piper pacer wing, but I feel like if I did that it would be years before I got this flying again.

I'm still trying to find out the strength differences between a stamped rib wing and a pre-war wing with 15 built up ribs. I am planning on doing the mods for increased weight other than going over 20 gal. fuel so that it will stay light sport eligible. I was also wanting to use a short mount with a sky-tec starter and mini alt to cut weight as well as being able to fit and not have interference with the firewall. I was looking at a 46 bc-12d that had a short mount with a generator and starter that fit. I don't know how they did it, but it was all there.

[Jim Herpst]

Re: Another pre-war wing question

Jim, that would be awesome...but it aint gonna happen now a days with the FAA.....
John

Opps You are correct. One needs to build a documented repilca or Swick / Clipwing. Thats what I am doing. Understand not everyone wants to clip the wings !!