|
-
POSTING RULES

-
Donate yearly (please).
-
Advertise in here!
-
Today's Posts
|
Insert Pics
|

01-05-2010, 10:32 AM
|
 |
|
|
Join Date: Mar 2005
Location: Dallas area
Posts: 10,768
|
|
Just as a reference point, my airplane is 17 years with well over 1000 hrs. and I have seen no cracking anywhere in the FAB set-up (built per plans). The last 750 hrs. have been with a compression ratio of 9.5:1 which I would assume would exasperate the problem.
__________________
Mel Asberry, DAR since the last century.
EAA Flight Advisor/Tech Counselor, Friend of the RV-1
Recipient of Tony Bingelis Award and Wright Brothers Master Pilot Award
USAF Vet, High School E-LSA Project Mentor.
RV-6 Flying since 1993 (sold)
<rvmel(at)icloud.com>
|

01-05-2010, 10:49 AM
|
 |
|
|
Join Date: Oct 2005
Location: 08A
Posts: 9,500
|
|
Quote:
Originally Posted by JordanGrant
Dan, does increasing the thickness of the plate effectively reduce the stress? (i.e., beefing up to a .090 plate instead of .063) If so, does that add 'cycles' nonlinearly as well?
|
I visualize the plate to be loaded like a diaphragm, so yes, increasing plate thickness increases distance from the neutral axis to the outermost fiber and thus lowers stress at the outermost fiber. Thickness has nothing to do with cycles. Cycles is simply the number of times the part is loaded and unloaded.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
|

01-05-2010, 11:12 AM
|
|
|
|
Join Date: Nov 2005
Location: Davis, CA
Posts: 1,156
|
|
Quote:
Originally Posted by JordanGrant
Dan, does increasing the thickness of the plate effectively reduce the stress? (i.e., beefing up to a .090 plate instead of .063) If so, does that add 'cycles' nonlinearly as well?
|
From the looks of the photo in the original post, that appears to be a bending or diaphragm failure. Bending stress goes as 1/(thickness squared) so increasing the thickness from .063 to .090 will decrease stress by about a factor of 2 (.09^2/.063^2). That'll make an aluminum part last longer. I don't have a fatigue curve handy for aluminum, but it probably isn't quite linear, so no guess on life increase. As Dan wrote though, steel (including stainless alloys) has the handy property that, if you decrease the stress below the so-called endurance or fatigue limit, it will never fail. The question is what that stress level is, and how to determine what the stress is on the part, in practice.
__________________
Lars Pedersen
Davis, CA
RV-7 Flying as of June 24, 2012
960+ hours as of June 30, 2020. Where did the time go?
|

01-05-2010, 11:22 AM
|
|
|
|
Join Date: Dec 2007
Location: Oakland, California
Posts: 7
|
|
Charles Wilhite
I am amazed to see that people are buying stuff from Charles Wilhite again.
It was just 3 years ago that he stiffed a bunch of us with his composite
canopy ripoff. He still has $1200 of my money. Beware.
|

01-05-2010, 05:27 PM
|
|
|
|
Join Date: Jan 2005
Posts: 98
|
|
After reading about an off-airport landing due to the carb partially falling off the bottom of the engine (nuts backing off) I've added a pre-flight check where I stick my hand in the inlet and make sure the airbox is not loose.
Doug
RV6 350hrs
|

01-05-2010, 06:26 PM
|
 |
|
|
Join Date: Feb 2006
Location: Virginia
Posts: 324
|
|
Quote:
Originally Posted by dmeloche
After reading about an off-airport landing due to the carb partially falling off the bottom of the engine (nuts backing off) I've added a pre-flight check where I stick my hand in the inlet and make sure the airbox is not loose.
Doug
RV6 350hrs
|
Yup, I actually do the same. My wife (and test pilot for first 40 hours) had the compression ring slip off during one of the test flights. The FAB got lodged in the bottom of the cowling, partially blocking airflow. This led to a partial loss of power. She declared an emergency and flew back to the airport and landed without incident. Now I tighten that thing WAY down and we also check it like you do prior to flight.
__________________
Jordan Grant
RV-6 N198G
Monthly donation started Mar '20
|

01-05-2010, 07:41 PM
|
 |
|
|
Join Date: Jan 2007
Location: Battleground
Posts: 4,348
|
|
Safety those intake bolts.
Not sure if you where referring to the bolts to the carb/servo or the bolts to the airbox? I was not happy with the fold over tab method of safety from Vans so I used Phillister Head Bolts and safety wired.
If you where talking about the AN3's that hold the airbox on, I apologize. [IMG]  [/IMG]
__________________
Smart People do Stupid things all the time. I know, I've seen me do'em.
RV6 - Builder/Flying
Bucker Jungmann
Fiat G.46 -(restoration in progress, if I have enough life left in me)
RV1 - Proud Pilot.
|

01-05-2010, 09:17 PM
|
 |
|
|
Join Date: Feb 2006
Location: Virginia
Posts: 324
|
|
Quote:
Originally Posted by JonJay
If you where talking about the AN3's that hold the airbox on, I apologize.
|
The Airflow Performance setup is different. You bolt the FAB into a ring that goes around the intake of the throttle body. That ring is held on by "squeezing" force supplied by a hex-head bolt. Kind of hard to explain, but easy to understand if you saw a picture.
__________________
Jordan Grant
RV-6 N198G
Monthly donation started Mar '20
|

01-06-2010, 06:55 AM
|
|
|
|
Join Date: Jun 2006
Posts: 316
|
|
Airbox plate
We've been making the air box plate for the FM-200 and FM-100 for Van's filtered air box out of .090 aluminum for a couple of years now. Seems the clearance of the box to the front of the cowl is important.
Don
|

01-06-2010, 07:49 AM
|
 |
|
|
Join Date: Jan 2005
Location: Venice, Fl
Posts: 1,020
|
|
Quote:
Originally Posted by JordanGrant
The Airflow Performance setup is different. You bolt the FAB into a ring that goes around the intake of the throttle body. That ring is held on by "squeezing" force supplied by a hex-head bolt. Kind of hard to explain, but easy to understand if you saw a picture.
|
OK how about a picture. I will be assembling my FAB soon and don't want to re-invent the wheel if it works.
__________________
Gary Palinkas - Gman.... VAF #161
Venice, Fl
RV-6 "Sassy" Flying 400 hrs since Oct 2011
Lycoming 0-360 A1A, FP Sensenich Prop
SARL #19 .... Van's Calendar March 2015
Although exempt several ways, =VAF= Dues paid to support this awesome site/family
|
| Thread Tools |
Search this Thread |
|
|
|
| Display Modes |
Linear Mode
|
Posting Rules
|
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts
HTML code is Off
|
|
|
All times are GMT -6. The time now is 04:00 AM.
|