RE: RP in aerospace

From: Monica & Glenn Whiteside (
Date: Fri May 15 1998 - 08:19:45 EEST

Hello Jungtae:

Based on my experience in commercial aerospace (business jets), we have a long way to go, especially compared to the automakers. Some of the reasons are that this business and a lot of the people involved in it are very conservative, especially here in the Midwest. It's extremely hard to convince people to "think out of the box." Funding of RP projects has always been hard to get but I think as management sees more of the applications and hears of more success stories because of RP use, it will improve. We're starting to work on many different applications and gaining momentum daily but educating the mainstream engineers and management can be a full-time job. Also there are a lot of FAA rules and regualtions to contend with and a lot of engineers don't want to use anything that might have the remotest chance of violating these. One of these is casting factor (currently 1.25). We'd like to push more cast parts but engineering contends we'll have to add a lot more weight using castings and the word "weight" always leaves a bad taste in their mouths. Until these old FAA regulations are reviewed and revised it will be a hard sell (as I understand it Boeing/McDonnell Douglas is working on this).

CNC is hard to beat in cycle times for machined parts and there is a lot of managers out there that still think that you have to "make chips" to make any parts. Until RP material costs and cycle times dramatically drop, it will be hard to beat CNC machining of aluminum.

We've looked at SLS (composite nylon) for composite tooling molds but we haven't seen the accuracy level that we can easily get from an aluminum mold and it's hard to seal the porous material. Durability and thermal cycling breakdown are other issues. Tooling size is a consideration also - a lot of our tools are 5-10 feet in length or longer. As far as using SLS for actual parts on the plane, we've looked at some but (especially for interiors) the material has to pass a horizontal or vertical material burn test and I haven't seen any SLS material hold up yet - especially for the vertical burn test!

Most of our current applications of RP are for concept and test models and also for mold patterns (lots of odd-shaped tubing and ducting).

Research assumptions are just that, assumptions. You have to start somewhere and I hope your academic advisors realize that assumptions are made to be modified, based on your research. That's what it's all about, learning to modify and adapt assumptions based on observation.

Good luck,

Glenn Whiteside
Cessna Aircraft

For more information about the rp-ml, see

This archive was generated by hypermail 2.1.2 : Tue Jun 05 2001 - 22:45:37 EEST