SonexBuilders.net

Long time lurker here. This forum is a great resources. During my readings I commonly come across comments alluding to the gratuitously high cost of aviation parts. After retiring from my career as a quant, I started building my Sonex. At the same time, a buddy who owns a tool & die shop, asked me to become his QC manager. Part of the deal was that I am able to use their shop to produce parts. We only produce a few parts for aviation. This is the story of one of the parts.

The part is a shim, .010 " thick, .307" in diameter with a .100 hole in the center out. The material specs call for 304 stainless, which must be DFARS compliant.

DFARS compliance requires the following: The material must come from specified countries, (Essentially NATO countries as well as Egypt, Isreal, Japan & Australia.) The material must also provide evidence of a continuous chain of control from the melt source. All this documentation has to be provided to the customer.

A minimum purchase is typically 50 pounds. 50 # of material will produce 15 to 20 YEARS worth of parts.

The material gauge is non-standard and difficult to find. The cost per pound of non-DFARS compliant material is $20.00. The cost per pound of DFARS compliant material ranges from $30.00 to $40.00 per pound. Post pressing, we send the parts out for passivation (like alodyne for SS for more about passivation https://www.besttechnologyinc.com/faq/w ... ssivation/) and florescent penetrant die testing. We also have to provide copies of the Bills of Lading to and from the Inspection lab, certs from the Inspection lab and copies of the testing results from the inspection lab. This is extremely expensive and quadruples our costs.

You seem to be focused on certified components - Sonex are not certified aircraft and do not require this level of QA.

My last recreational aircraft, a kit build from Europe, was metric from nose to tail - not certified component to be found. The result is a relativly cheap aircraft to purchase & maintain. It helped that this was a composite airframe in the extremely low parts count. It did not have the high speed cruise of a Sonex but handled wonderfully and had a very safe stall speed of 30 Knots - high speed cruise 120 knots. Rotax 912 ULS engine.

I don't think it can be argued that Certified components have a level of assurance, well above most non certified, however for aircraft of the Sonex level of aviation this is, in my view, gross "overkill".

Skippydiesel wrote:You seem to be focused on certified components - Sonex are not certified aircraft and do not require this level of QA.

I think he was just posting a general interest story, not Sonex related.

Bryan Cotton wrote:

Skippydiesel wrote:You seem to be focused on certified components - Sonex are not certified aircraft and do not require this level of QA.

I think he was just posting a general interest story, not Sonex related.

As was I . This however a Sonex Forum and thats how I happen to read his comment.

Aviation parts: You can get better stuff, but you can't pay more for them!

Sonerai13 wrote:Aviation parts: You can get better stuff, but you can't pay more for them!

That would make a great bumper sticker!

Skippydiesel wrote:My last recreational aircraft, a kit build from Europe, was metric from nose to tail - not certified component to be found. The result is a relativly cheap aircraft to purchase & maintain. It helped that this was a compost airframe in the extremely low parts count.

Hi Skippy, I'm a bit worried about you flying a compost airframe, though I guess we should all be concerned about eventual recycling ;-)

Peter

Thanks Peter - all for compost, bit pongy but the only way to grow an aircraft:)