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/Recently, QBA has received several letters from builders who have mentioned that they are making substitutions in their selection of materials, particularly foam. It seems that several individuals have tried using billets of buoyancy blocks (the foam used around barges and piers). We were somewhat concerned about this, so we asked Gene Sheehan and Burt Rutan to comment on the safety aspects. Below is a copy of the reply received from QAC. Our letter to Mr. Rutan went unanswered. -Ed./

"We at Quickie do not recommend substitution of materials as a general rule. There are a number of reasons for this:

1. Obviously, we cannot recommend composite materials that we have not tested. There are many properties in the foams, resins and cloth that can only be determined by testing. This is particularly crucial in the case of the foams and resins. Foam manufacturer's specifications are notoriously inaccurate. Resin properties mean absolutely nothing by themselves. Workability of a resin system is a term that is virtually impossible to put a hard number on. In the case of cloth, once again, the finish or sizing on the cloth is impossible to measure unless laminations are performed.

2. The relative ease of FAA inspections our builders are experiencing is partly due to the fact that the FAA knows what the builder is building his aircraft out of. That is, a kit approved by QAC.

3. Most first-time builders are simply not capable of distinguishing the difference between suitable materials and unsuitable materials. We at QAC have no way of determining which builders have the necessary knowledge and experience, but based on our experience, it would be a small percentage.

In the particular instance you cite, I note that you are concerned. We are concerned also, as we do not have the specifications from either (deleted) or (deleted) for these particular blocks of foam. If we did have this information, we could possibly comment on the suitability of this substitution.

In the past, we have allowed some substitution of materials by our builders. This has been handled on a case-by-case basis. One example: Several Varieze builders have been allowed to substitute materials from their kits for Quickie and Q2 materials. Another example has been when builders have made mistakes and need replacement materials.

QAC tests new materials and ideas all the time and those that we approve can be used by our builders. Those that we do not approve, we usually do not even mention. QAC does not encourage anyone to attempt to build a Quickie or Q2 without purchasing a kit. Part of the money in the purchase price of each kit is for builder support. In some cases, builder support has required substantial expenditures in time and money for some individual builders including: testing of engines, propellers, material samples, etc. QAC only supports builders who purchase kits.

QAC will not publish specifications for the various materials used in the aircraft because we feel that "a little knowledge is a dangerous thing". Some of these specifications are somewhat subjective in nature and require knowledge and training that very few potential builders possess.

We will continue to work with individual builders on a case-by-case basis. Even in these cases, we do not make a blanket endorsement, we only allow a specific substitution for a specific component.

The liability for QAC in allowing substitutions is very high. Therefore, our policy must be that anyone who substitutes materials without our approval has just become his own aircraft designer."


/Admittedly, we had expected such a protectionist type of response from QAC. There is a potential problem in letting builders select their own materials and sources. QAC is correct that quality control would no longer be an item that they could easily regulate. A less esoteric point is the fact that QAC is in the business of selling aircraft kits. Builders who circumvent established dealers cut into the profit line. We are not suggesting that QAC is deliberately scaring builders with false information, but it would hardly be in their corporate interest to help someone find a cheaper material somewhere else.

Although QBA does not have loyalties to any particular supplier (we WANT cheaper materials), our own liabilities restrict us from printing individual recommendations until the material can be established as safe for the average project. In order to meet that requirement, we need DOCUMENTED proof that a substitute meets or exceeds the engineering properties it is to replace. For most cases, this will also include side-by-side testing in a role similar to that expected on the actual airplane. We realize that this may prevent some otherwise very good materials from being recommended, but a conservative stance in these areas is only prudent. Like QAC, QBA does not wish to find itself in a position of disseminating information, which most builders would be unable to adequately evaluate, and whose use might have serious results. -Ed./

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