VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #11  
Old 03-20-2013, 01:23 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,972
Default

Quote:
Originally Posted by Hal-san View Post
Getting it off is pretty quick and easy. Getting it back on is where the difficulty comes into play.
This could be affected by a number of different factors...

- The adjustment of the oil hose clocking on the oil cooler (mentioned in the construction manual).

All the RV-12's I work on, will allow me to lift the cowl straight up into place and have the oil cooler drop on to the mounting lugs without me doing anything other having the cowl properly aligned while I raise it.


- Trimmed length of the exhaust pipe.

If I remember correctly, trimming so it extends about 7 inches beyond the bottom of the muffler is about right.


- Lastly, proper installation of the cowl.

If the cowl was pushed/forced into position when it was being drilled to the hinges to alleviate unwanted gaps, etc., you will have to apply the exact same force every time you install it. It also will contribute to puckers and distortion in the cowl shape, and reduced longevity of hinges and attachment rivets.
Another factor is whether the duct frame was installed with exactly the prescribed 1/4" gap around the entire perimeter of the radiator.

Any one of these will cause difficulty to varying degrees. A combination of all three could definetely cause it to be difficult.

Last edited by rv6rick : 03-21-2013 at 11:38 PM. Reason: Removed expletive
Reply With Quote
  #12  
Old 03-20-2013, 04:25 PM
NASA515 NASA515 is offline
 
Join Date: Nov 2011
Location: Hansville, Washington
Posts: 536
Default

Quote:
Originally Posted by rvbuilder2002 View Post
In all fairness to the 1000's of people reading your opinion Bob... what aircraft are you comparing the RV-12 too?

Have you ever removed the cowling from a Piper or Cessna or Beachcraft?
I have. Many times.
Some are easier than others. Some are more involved than the RV-12.

And then some... I think were designed just to give certain people something to complain about...
C'mon Scott. Lots of airplanes have had easily openable cowls, not much different than the hood of a car (sorry - bonnet for the U.K. guys), that allow you to see the engine. Like the Cherokee - a quarter turn of two Dzus fasteners on each side and pretty much the whole firewall forward is open to see.

To me, this is not just a Maintainability issue, but also a Safety issue, in that you get to look at the engine during every pre-flight, instead of just an oil dipstick. If there are any leakage, rubbing, or other issues, they are front and center. Sort of like John Peck's leaking exhaust.

As I get ready to make the first flight on my airplane, I note in the Flight Test Guide that it calls for pulling the cowling after the first flight. Ugh! That means I need another guy (I definitely cannot do it by myself!) And they're not just walking by my hangar door. When I installed the lower cowl a few weeks ago, I didn't have another guy - so I (tried) to do it with my wife. We almost made it, but in the end, we couldn't get the oil cooler holes and everything else to line up all at the same time, plus I scratched my paint pretty good. So I had to take it off again and wait until Tony T. came over a few days later on the ferry and we got it installed (with a lot of pushing and shoving and a few bad words.) Maybe, as you suggest, it wasn't made right and I'll have that problem for the rest of my RV-12 life.

Try not to be too defensive, Scott. Continuous Improvement is a mantra I preached for the last ten years of my working career. I believe in it. Meanwhile, many airplanes with problematic cowls have after-market mods to improve or rectify this very shortcoming - even Vans - as you can see by doing a search of VAF for things like camlocks etc. Some businesses - like Skybolt - even thrive on rectifying the situation.

Since you asked, here are an assortment of easy-opening cowls. Why even in my old favorite - the 737-200 - I could pop open the side cowls by myself in about two minutes, expose the whole engine, and latch them back up by myself in not much more time. And I've done it many, many times!

Bob Bogash
N737G

Super Cub, Cessna 140, Cessna Caravan, Beech Bonanza, Cherokee, Piper Arrow













Reply With Quote
  #13  
Old 03-20-2013, 05:21 PM
N223JH N223JH is offline
 
Join Date: Apr 2008
Location: Boerne, TX
Posts: 228
Default

Bob, Check your PMs.
Reply With Quote
  #14  
Old 03-20-2013, 05:36 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,972
Default

Quote:
Originally Posted by NASA515 View Post
Just wondering of the difficult part of the cowl installation process resulted in less surveillance than would be the case if more easily removable.

Bob Bogash
N737G

Finished my airplane today - 1 year and 2 days.
Quote:
Originally Posted by NASA515 View Post
C'mon Scott. Lots of airplanes have had easily openable cowls, not much different than the hood of a car (sorry - bonnet for the U.K. guys), that allow you to see the engine. Like the Cherokee - a quarter turn of two Dzus fasteners on each side and pretty much the whole firewall forward is open to see.
Bob,
I am not being at all defensive. I was just asking you to qualify your statement.

Your first post was talking about removal of the cowl. Now you are talking about looking inside. Two totally different things.

I guess all I can really say is that the RV-12 has the same cowl it has had since day one. So that is the cowl it had when you decided to build one.

BTW, other than the super cub cowl (which I think very few people would consider attractive for an RV), I think you are putting far to much value in how much (limited) inspectablility any of those engine comparments actually have when the cowl is opened.

Last edited by rv6rick : 03-21-2013 at 11:42 PM. Reason: Removed expletive in quote
Reply With Quote
  #15  
Old 03-20-2013, 05:52 PM
NASA515 NASA515 is offline
 
Join Date: Nov 2011
Location: Hansville, Washington
Posts: 536
Default

I voted with my wallet, Scott. You don't have to convince me on the merits of the RV-12. But, just like a car, a house, or even a spouse, nothing is perfect. I thought our mutual goal was to make a fine product even better. I don't need, or plan to get defensive about making comments on this Forum.

As to "removing" the cowl vs "opening" the cowl and looking inside, there is either no difference or a big difference when it comes to the RV-12, depending upon your perspective. The airplanes I pictured (what's so bad looking about a Bonanza cowl?), allow you to LOOK inside without removing the cowl. The RV-12 does not. If you want to look, you have to remove the cowl.

I find it comforting to look, and doing that during every single pre-flight is all the better.

As to there being "limited inspectability", I guess it depends on the individual airplane - but in general, I do not agree with that statement at all. It's very much like popping the hood of your car. You might not be able to see everything, but there's a lot to see. Have you popped a Cherokee cowl lately?

Bob Bogash
N737G
Reply With Quote
  #16  
Old 03-20-2013, 05:52 PM
aerofurb aerofurb is offline
 
Join Date: Jul 2009
Location: High Wycombe, UK
Posts: 278
Default

At work I'm responsible for the maintenance on over 40 GA aircraft of various types.

As Scott said, whilst you can open the cowlings on some of the PA28 variants (140, 151, 161) and other types, how much can you usefully see? Many of the PA28s (like the PA28-235 in the photos, Arrow, 180, 181, 236) have a one piece removeable top cowl and are rarely removed as part of a pre flight inspection.

The RV-12 top cowl is pretty easy to remove with practice and you can see enough with experience to satisfy yourself that all is well.

The easiest cowlings to remove completely are probably the C152 - pure joy!
__________________
Jerry Parr
England
RV-12, G-TWLV


Loving Rotax....
Reply With Quote
  #17  
Old 03-20-2013, 06:40 PM
rvbuilder2002 rvbuilder2002 is offline
 
Join Date: Jul 2005
Location: Hubbard Oregon
Posts: 6,972
Default

Quote:
Originally Posted by NASA515 View Post
I voted with my wallet, Scott. You don't have to convince me on the merits of the RV-12. But, just like a car, a house, or even a spouse, nothing is perfect. I thought our mutual goal was to make a fine product even better.
I understand your point Bob.

I will end with pointing out what gets discussed on this forum a on a regular basis, by the more design savvy members....

Every design is a compromise.

Designing the cowl on the RV-12 with hinge open panels that would have allow for pre-flight inspection of the entire engine compartment, would have directly gone against the goal of maximizing useful load and minimizing cost (possibly far more weight and $$$ than you might imagine).
I believe in the past you have said you felt both these were positive aspects of the RV-12.
Reply With Quote
  #18  
Old 03-20-2013, 07:32 PM
Bruce Russell Bruce Russell is offline
 
Join Date: Jul 2008
Location: Clayton, GA
Posts: 175
Default

This is one of the greatest examples of thread drift I have ever seen. The first three posts actually address the issue of exhaust system question. The next 15 posts are entertaining, but not very helpful to BigJohn. Check the thread before you post.
__________________
Bruce Russell
Clayton, GA

Simultaneous Repeat Offender

Last edited by Bruce Russell : 03-21-2013 at 08:12 AM.
Reply With Quote
  #19  
Old 03-21-2013, 12:23 PM
RFSchaller RFSchaller is offline
 
Join Date: Oct 2010
Location: Phoenix, AZ
Posts: 2,114
Default

Nothing wrong with thread drift. It provides insight on what other owners are thinking about. I agree that Vans has a great product and sometimes seem to miss the opportunity to use forum input to improve it. I know it's not "official" feedback to Vans, but the forum is a market research gift to them.
Reply With Quote
  #20  
Old 03-21-2013, 11:20 PM
jetmech's Avatar
jetmech jetmech is offline
 
Join Date: May 2007
Location: Fairfield, CA
Posts: 91
Default

Quote:
Originally Posted by BigJohn View Post
I'm in the process of performing my second condition inspection. I found that there has been some significant leakage of exhaust gases from the right rear exhaust pipe muffler joint. See photo. I will have to remove the muffler and investigate of course, but wondering if anyone else has seen this?

Aloha John, replace the springs PN 938-795 (66MM )$3.28 ea and add some high temp anti-seize to the joint area when you install in. you can add a bead of high temp RTV top to bottom on one side of the spring to dampen it also

Lee
IRMT & A/P
__________________
RV-7
Chelton Flt sys
TMX REDGOLD IO-360/Dual EFII
RV-3a/o-320 Old School style Brada
Speed is life! Bank it & Yank it for the G's
Xtra Dues paid 2017 thxs again DR!
Home base -o88
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 03:50 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.