gahorn wrote:
I am curious as to what your thoughts are regarding why you believe you can produce a gear better and cheaper than Cessna, considering that you've expressed your opinion they've already been producing thousands of them in the same material you presumeably expect to use to produce only a few.
What are you thinking about? and how does your imagined product excel beyond that already available?
But I'm puzzled as to your inquiries, and the reluctance to obtain genuinely-valid engineering data from the mfr'r by someone planning to undertake such a serious project which clearly will have limited appeal, market, yet great risk.)
By the way.... without engineering drawings it is difficult to imagine which measurements might prove helpful to you. Simple thickness, length, hole sizes are unlikely to prove useful. What you likely need is detailed profile measurements
No confrontation George, I'm glad to discuss this. Helps me greatly and keeps me honest with myself.
Forgive the length of this response, I want to provide detailed answers.
What I'm thinking is this - Cessna makes a gear leg, and prices it according to their corporate pricing structure,which is designed to support a huge bloated bureaucracy, a thousand secretaries, worker's compensation, handicapped person fire exits every eleven feet in the factory, vice presidents of meeting scheduling, etc. They also price their gear leg based on liability insurance for a large company, and Cessna's insurance carries with it the hundreds of times Cessna has (unfortunately) been the target of a lawsuit. I have none of those issues.
Any lawsuit of any size will bankrupt my little one-man company within the first 30 seconds probably. Any insurance I carry will be a lot less expensive than theirs. I have no advertising costs. I have no significant business overhead. I have no debt to service. I am not contract bound to a large dealer network, who will be adding their markup on to any parts. In short, I don't need to make anywhere the amount of profit that they do.
Therefore, it appears to me that I can make a reasonable profit and still sell a quality gear leg for less than Cessna can.
As far as quality or design, Cessna has made almost no changes to their gear boxes ever. Cessna used extrusions because they were cheaper not better. They were originally designed for minimum time and effort and manpower, for efficient mass production. I do not believe maximum service life, or maximum damage resistance was in the top 3 on their list. I have the ability to make these gear boxes out of CNC cut billet, which means I am not restrained by the two dimensional "linear" nature of extrusions. That means I can put more meat where there needs to be more meat.
Cessna switched to tube spring gear years ago, so they logically don't have any strong impulse to improve the flat spring gear boxes for older airplanes.
My parts will indeed have limited appeal. I have no delusions about selling hundreds and hundreds of them. But my market would be partly the tailwheel conversion kits that need parts, and (since they will work as replacement parts) partly the needs of people rebuilding or repairing damaged aircraft.
I am not reluctant to spend a little money where it is needed, I am reluctant to over-spend or spend money where it is not necessary. Spending $500 on a copy of a drawing, when I can measure an existing (good) part for a six-pack and lunch conserves my pitiful cash reserve for other uses.
The profile (cross section) of the Cessna gear leg is, I believe, rectangular. It is .6875 inches (nominal) thick until 1961 or 62 if I am correct. I do not think they tapered the thickness of the gear legs... from an engineering perspective they accomplished the same result by tapering it in planform, which saved them a lot of money and time when they built the part. This is completely consistent with Cessna's cost philosophy of the 1950's.
Basically I do not think I'm any smarter than Cessna. Not by a longshot. I'm just in a unique position where I can make a buck in a small niche, providing an aftermarket improved part, the same way people make aftermarket versions of certain stock parts for Honda's, Chevy's, etc. Chevy can make 1956 Corvette exhaust manifolds by the millions, but there are still headers and tuned exhausts that have a market.
