Looking for Cessna disc brake STC

[flyboyinpa]

I wrote to E.A. Bigby for the STC for installation of Cessna rudder pedals, master cylinders, and axles, Aircraft Spruce and Speciality wheel fairings, and Cleveland brakes and wheels. STC No. SA4797NM but got the letter back marked undeliverable. Anyone have any idea where I can get this STC??
Thanks, Dave

[Dick Smith]

Re: Looking for Cessna disc brake STC

Dave, Bigby's STC was a "one-time only" deal, for his plane alone. Dick

[flyboyinpa]

Re: Looking for Cessna disc brake STC

Thanks Dick

[fearofpavement]

Re: Looking for Cessna disc brake STC

We have the cessna wheels and brakes (no wheel pants) on a BC-12D that was done on a 337 in 1997. I don't know where the "acceptable data" came from as there are a number of drawings included. Anyway, I don't know if the FAA would do another field approval or not. It says something like "this aircraft only, completion inspection required" At any rate, it has a bunch of drawings of how to modify the axle and install the Cessna rudder pedals and has some reference to instructions for continued airworthiness by using certain parts of the Cessna 150 manual and so forth. The IA is deceased but the mechanic is still around and lives in SC I believe. As I said, I don't know what the original source of this data is but it worked in this case and if someone wants it I could copy it all and send it.

[Pearson]

Re: Looking for Cessna disc brake STC

What would it cost to hire a designated engineering representative to do a disc brake STC. It seems like every month or two someone is asking about this. If I had the time, I would do it myself.

[jdoran]

Re: Looking for Cessna disc brake STC

I haven't been able to contribute much, but I'd offer to do some legwork if the group thought it was a worthwhile project:

I am in the trailer manufacturing business, and we make our own axles, so I am working with disc and drum brakes everyday. We merely rotary-weld spindles to axle tubes, then everything else (bearings, hubs, seals, etc) is easily installed on the spindles.

The master cyllinders and reservoirs are readily available from any of the aviation supply houses. The problem seems to be getting the brake system converted on the running gear.

I'll bet the components needed to put disc or hydraulic drum brakes on the Tcraft are available to buy commercially. It would only require replacing the spindle on the landing gear, then possibly a wheel change.

Here's two links to give you an idea of what's available:

https://www.trpintl.com/page11.shtml

https://www.dexteraxle.com/inc/sdetail/6839

Here's two questions (I'm on floats, so wouldn't know):

1) What are the bearing bores for the inner and outer bearings on the factory spindles?

2) What is the wheel (rim) diameter and width (between beads) on the t-craft?

If I can, I'll see if a spindle, rotor (or drum) with brakes, and a suitable wheel is available, and what the costs would be per side.

John

[Dick Smith]

Re: Looking for Cessna disc brake STC

John, I put the calipers to a standard, tapered axle that was cut off of a BC12D gear...Got .745 inch at small end and 1. 245 inches on the big end. The item above the axle is an adapter that fits over the axle and inside the bore of a ski pedestal. Dick

[VictorBravo]

Re: Looking for Cessna disc brake STC

What does the new Taylorcraft factory use for wheels and brakes? What modifications or changes did they make to the older T-craft landing gear to make this work?

Based on my recent experiences with the FAA, it would be very likely that they would green-light an upgrade to a later factory version.

However, I have it on reasonable authority that you want to keep the heel brake setup, because Cessna style toe brakes cause interference between your shoe and the big moving control yoke arch.

[fearofpavement]

Re: Looking for Cessna disc brake STC

The C-150 pedals we have in our BC-12D don't really fit in there very well but the disc brakes sure do work great. So I wouldn't want to go back to the heel brakes.

[jawinn]

Re: Looking for Cessna disc brake STC

I'm just going off the top of my head, but would it be unreasonable to use heel brakes ( I thinkthey're hydraulic) off a Citabria? I don't have any experience dealing with the FAA on mix and match parts...337s...etc. I'm new to the aircraft ownership thingy.

[VictorBravo]

Re: Looking for Cessna disc brake STC

That's sort of what I meant... keep the heel brake location but have those heel brakes operating hydraulic disc brakes instead of pulling on a cable. Egads... even Cub brake pedals and master cylinders???

The story I heard was that Cessna rudder/brake pedals will make your feet, the pedals, and the control yoke arch all get tangled up, causing a groundloop.

My Shinn brakes work well enough to hold the airplane on almost a 100% runup... but if I were landing in hard crosswinds or doing more demanding types of landings I think I'd appreciate having the hydraulic discs. It's one thing to keep a 65 or 95 horse engine from moving the plane from a standstill, but I strongly suspect it's another thing altogether to bring a 1200 pound airplane flying at 40+ mph to a stop in gusty winds.

[Ragwing nut]

Re: Looking for Cessna disc brake STC

Should not be complicated to get the F-21 brake system approved on a field apporval. I have done it before when we rebuilt a F-21 and had to use a perfect F-19 fuselage because we could not come up with a F-21 fuselage and modified it up to F-21 specification. The REAL problem is the costs involved. $700 for wheels and brakes, $600 for master cylinders, removal of engine and boot cowl to weld master cylinder supports, modification of landing gear or purchase of F-21 gear. Minimum $3000 not including the paperwork hassle. In my opinion, cost prohibitive. I have quite a few hours in a F-21 and the brakes as a by product definitely increase the crosswind component but I don't recommend trying it.

Second option WAS Mike Swick. He has an STC for installing 5.00x5 Cleavelands with the master cylinder mount inside the gear leg. Problem with that is he won't sell any STC's.

Mike

[N96337]

Re: Looking for Cessna disc brake STC

There are copies of field approvals in the Taylorcraft Club library..or maybe it's the foundation... whatever... at any rate, there are 3 that I have on file here... #10, #16, and #25 are the reference numbers.
The #10 field approval is quite detailed and well drawn out! I found #25 very interesting in that he used a weld on axel from WagAero, and included is the test results for the materials. I'd get copies of these and get with your IA and make a nice presentation to the FAA... who knows, you may just get the whole mess field approved!
JH

[Pearson]

Re: Looking for Cessna disc brake STC

I looked into getting a field approval for disc brakes awhile back through the Portland FSDO. They told me, in no uncertain terms, that they don't issue field approvals anymore without engineering data. So if someone out there gets disc brakes approved on a field approval, I would sure like to know about it.

[Pearson]

Re: Looking for Cessna disc brake STC

I have been pursuing the idea of coming up with a way to put disc brakes on a Taylorcraft. Since I own two BC12Ds, this is the model that I have been focusing on. I have spent a great deal of time, and money just so far, discussing this with a retired aircraft engineer and a DER. From what both of them are telling me, this can be done but the cost would be outragous. The question came up as to how many of these modifications could the costs be spread over. That begs the question of just exactly which models would this be applicable to? So can someone tell me specifically which Taylorcraft have the tapered axle and the rudder pedal setup identical to the BC12D? Is it all aircraft on the A-696 Type Certificate? Prewar Bs, BCs, etc???? Apparantly the F-21 has disc brakes. But did the F-19?

Where are these copies of past disc brake approvals #10, #16, & #25. The DER is telling me that any kind of approved paperwork will help make it easier. I have looked on the FAA website and the only thing I see is the one by E.A. Bigby, and I don't like his design. Where are these others? The DER is saying there is no way the FAA is going to approve anything to do with brakes on just a 337. Those days are long gone.


If there is a large enough market for this, I would be willing to do it as a business venture. I just want to know how large the possible market is and specifically which airplanes to list it as applicable to.