BTW Vance, According to McMaster Carr steel springs are good to 250 F and
302 SS are good to only 550 F.

Paul Lamar

********************************************************************************

That is correct Paul, but keep in mind that those temperatures were set based
on the ALMOST material historysis ability......with that mouthful
said,........ie: let's say a 2" long ss tension spring operating in a 550 deg F
ambient, has a maximum stroke (stretch) of 1" is selected, what the
manufacturer is guaranteeing is that the spring will operate from 2" to 3"
satisfactorily............HOWEVER if you only stroke it to a fraction of its
stroke, let's say 25% (1/4") it will operate in a much higher temperature
environment satisfactorily.

Also.....The manufacturer's temperature limits are very conservative, their
LAWYERS cover their asses good.........ie: I've submitted product designs with
2.5 safety factors built in and by the time they went into production they had
been TRIPLED by the "Legal/Paper Staff", as a matter of fact one of these
companies was sold years later, and they tried to sue me for "Over Designing
their Main Product" and "Causing the Company Manufacturing Losses">>>>>>>>Yes,
I countered sued and after 15 Months they had no choice but to pay me instead
as I threatened to go public :) I only had to sign a perpetual "Keep your Mouth
Shut Agreement" :)
 Shame, what a waste of time and money, but that's "Corporate America" for you.

                                                     Butch

"historysis" are you being funny or do you mean hysteresis :)
Even my NetScape spelling checker had problems with that :)

Well this is a case if the springs fail holding the exhaust flex joint
together right next to the engine one is in real deep dog pooh.

BTW Mark this jpg did not completely load on the Best Practices web site.
Also you might mention it is a good idea to put the fuel system
on the cold side of the engine. IMHO this test pilot narrowly
missed an in flight fuel fire. Now that can ruin your whole day.
Also did you mention the 1700 F EGT cruise mixture setting?

Paul Lamar


The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.