I get many calls about the options available when doing engine upgrades on the Taylorcraft BC-Series airplanes under STC # SA1-210 (formerly known as the Gilberti STC). It usually takes a pretty long phone call to go through all of it. So I thought maybe it would be helpful to share some of the main points here. If you are seriously considering the purchase of upgrade paperwork, I recommend that you read through this post, and then study our latest catalog. This should help you get a bit up to speed on the configuration choices you have. Write down your questions and then give me a call and we'll figure out the best package for your Taylorcraft.
I'll start off with some background history and this should help you understand how this STC has evolved and maybe it will explain a bit about how the FAA approvals are structured.
|2016 Keith & Joann Walker from Charleston IL|
BC12-D with STC SA1-210 Configuration A
ORIGINAL STC 1958 - Jack Gilberti
Configuration A incorporates a C85-8 engine with the original (short) engine mount and the resulting configuration is equivalent to the factory TC A-696 model BC12D-85. This retains original cowl/baffle/engine control cables/exhaust/ etc. The fuel system has to be updated to have at least one wing tank and the fuel lines have to be verified at least 3/8 inch size. This configuration has no electrical system. It has the option to install some simple wing fitting modifications that allow maximum weight to upgrade from 1200 to 1280 pounds. Eligible propellers are the same as the TC A-696 model BC12D-85.
Configuration B incorporates a C85-12 engine with a replacement (long) engine mount and the resulting configuration is equivalent to the factory TC A-696 model BC12D-4-85. The "4" means that the engine mount and cowling are extended longer by about 4 inches. Originally it was expected that the starter and generator would be the old style (heavy) Delco brand. So that's the reason for the mount extension. This configuration requires conversion to a larger baggage compartment and added electrical system with battery mounted about 24 inches aft of the seat back. This offset's the CG change due to the extended engione mount. The fuel mods are required same as config A. Cowling requires modification, a different exhaust is required, longer control cables are required. The same max. weight of 1280 pounds applies if optional wing mods are done.Eligible propellers are the same as the TC A-696 model BC12D-4-85.
If you are considering this option (or any long mount option), I always recommend that you try to find an airplane already modified or a model 19 or F19 and go for a flight. You will discover that the handling characteristics are different from what you may already know as the nimble B-series Taylorcraft. To some this may be desirable. To some, it can be a surprising disappointment after going through all the work to do this mod. It's hard to describe this difference, but just imagine that your rudder authority is just a bit slower in reaction time. Not in a bad way, just different.
STC UPDATE IN 1971
Configuration B was revised to declare the resulting configuration the same as TC 1A9 model 19. This configuration is physically exactly the same as the prior described Configuration B (BC12D-4-85) in every way, except it was approved to operate at a maximum weight of 1500 pounds (if optional wing mods are done) - equivalent to the factory model 19 per TC 1A9 (under CAR 3 regulations). As such it also became a "Flight Manual Required" airplane and no longer a "placard only" airplane. All of the same fuel/cowl/exhaust/baggage/etc mods apply as aforementioned Configuration B. Eligible propellers are the same as the TC 1A9 model 19.
By the STC wording, you essentially have the option under Configuration B to go with 1280 or 1500 pounds maximum weight. The former keeps the airplane within the LSA weight limit. The latter takes the airplane over the LSA limit.
STC TRANSFER TO CAP in 2010
Certified Aeronautical Products took over the management of the STC in 2010. We have expanded the options beyond those approved in the STC, made possible through major alterations approved by a DER. We call these STC deviations. These major alterations do not require additional STC but are incorporated under FAA form 337. Rather than mention of them all here, please look at the catalog. For example, a DER can approve certain non-standard propellers. Another example.... we offer DER approved deviation paperwork to substitute a C85-12 engine on Configuration A. This makes it possible to have an electrical system (with the short engine mount) when modern lightweight starter and alternators are used... because we've determined that they fit. It's a tight fit, though. You'll find you might have to de-mount the engine to get your starter on and off. But its not that hard to do. So the DER approved deviations have opened the door to many additional configuration options for these modified Taylorcrafts. Again, most are listed in our catalog.
Previously, I mentioned different exhaust. Well, when you mount an alternator to the back of a C85-12 it will interfere with the cross-over tube on the original B-series exhaust. Something has to be done. If you want to fabricate your own, we can provide the Gilberti drawing for the model 19 style that extends the cross-over pipe farther aft. The same exhanst configuration was done at the factory for the BC12D-4-85, 19, and F19 models. Another more popular option nowadays is to convert to the Luscombe style split headers or Cessna 150 Hanlon Wilson style exhaust. We can provide DER approved paperwork for either of these or others, like Aeronca and more.
OTHER STC SA1-210 Deviation work
Our DER has approved some de-rated installations of C90 or O-200A engine (de-rated by limiting RPM to that for 85 hp).
Through DER and FAA FSDO/ACO coordination, we have also supported a few deviations to substitute an O-200A engine rated at 100 hp. This is equivalent to TC 1A9 model F19. We had to do an analysis of a specific engine mount design, so a new mount is required (or you can order an F19 mount from Univair).
There are a lot of options. Study our catalog and then give us a call with your questions. We will gladly help you tailor your Taylorcraft with approved paperwork.