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Trimming the cowling

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Mike Whisky

Joined: 05 Jun 2006
Posts: 336
Location: Switzerland

Posted: Wed Jan 23, 2008 3:03 pm Post subject: Trimming the cowling

Guys,



I am hesitating to trim the cowling due to the fact that the straight edge method doesn't give me the possibility to make a line along the side. 

How did you do it?



Michael

_________________
RV-10 builder (flying)
#511

dlm46007(at)cox.net
Guest

Posted: Wed Jan 23, 2008 3:51 pm Post subject: Trimming the cowling

You need the flexible steel scale which bends nicely. Another technique is

to mark the distances on the fuselage about every three inches and connect

the dots. Then make an initial cut about .1" short of the aft end of the

starting cowl so that additional trimming can take place with files and

sanding blocks. IIRC we started with the bottom and matched the top to it.



--

Jim Berry

Joined: 10 Jan 2006
Posts: 237
Location: Denver

Posted: Wed Jan 23, 2008 6:57 pm Post subject: Re: Trimming the cowling

I was able to trim mine to a very close fit with 2 layers of masking tape. Two inch wide tape works well for the cowl. Position the first layer of tape so that the forward edge matches the forward edge of your sheet metal. Position your upper or lower cowl per Van's instructions. Now position a second layer of tape the same width as the first so that the aft edge matches the aft edge of the first layer of tape. The forward edge of the second layer is your cut line.



Jim Berry

40482

drfred(at)suddenlinkmail.
Guest

Posted: Wed Jan 23, 2008 8:14 pm Post subject: Trimming the cowling

Michael;



I did the first cut on the side of the cowl tonight.  I used a laser 

level and picked three points, one at the inside of the inlet, one at 

the outside and one at the aft edge, then drew the line on the cowl.  

I'll use that as my reference line.  Next, will trim the bottom 1/2 up 

to that line.  Will see how well that works tomorrow night. 



Question to those who used skybolt fasteners for the sides.  How thick 

of an aluminium strip did you use for the side fasteners?  0.050 as per 

the top strip?  

Dr Fred. 



Michael Wellenzohn wrote:

 	  Quote: 	
		   



 Guys,



 I am hesitating to trim the cowling due to the fact that the straight edge method doesn't give me the possibility to make a line along the side. 

 How did you do it?



 Michael



 --------

 RV-10 builder (engine, prop, finishing)

 #511





 Read this topic online here:



 http://forums.matronics.com/viewtopic.php?p=160067#160067

dmaib@me.com

Joined: 25 Apr 2006
Posts: 454
Location: New Smyrna Beach, Florida

Posted: Wed Jan 23, 2008 8:27 pm Post subject: Trimming the cowling

Jim, I am confused. It sounds like the second layer of tape is  

exactly on top of the first if the aft edge of the second layer  

matches the aft edge of the first layer. I must be missing something  

here. (would not be the first time!) Is the first layer of tape on  

the sheet metal? The second layer on the cowl? Now I am confusing  

myself even more! ^_^



David Maib

40559



On Jan 23, 2008, at 8:57 PM, jim berry wrote:






I was able to trim mine to a very close fit with 2 layers of masking  

tape. Two inch wide tape works well for the cowl. Position the first  

layer of tape so that the forward edge matches the forward edge of  

your sheet metal. Position your upper or lower cowl per Van's  

instructions. Now position a second layer of tape the same width as  

the first so that the aft edge matches the aft edge of the first  

layer of tape. The forward edge of the second layer is your cut line.



Jim Berry

40482





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=160132#160132

_________________
David Maib
RV-10 #40559
New Smyrna Beach, FL

mritter509(at)msn.com
Guest

Posted: Thu Jan 24, 2008 4:31 am Post subject: Trimming the cowling

I used 0.063 all around which was hard to bend around the curves.  Also hard to bend the tabs to match the slope of the cowl.  If I had it to do over again I would try 0.050.

 Mark

 RV-10/N410MR

 185 Hrs.

<html><div></div></html>

 > Date: Wed, 23 Jan 2008 22:11:10 -0600

 	  Quote: 	
		   From: drfred(at)suddenlinkmail.com

 To: rv10-list(at)matronics.com

 Subject: Re: RV10-List: Trimming the cowling

 --> RV10-List message posted by: "Fred Williams, M.D." <drfred(at)suddenlinkmail.com>

 Michael;

 I did the first cut on the side of the cowl tonight. I used a laser 

 level and picked three points, one at the inside of the inlet, one at 

 the outside and one at the aft edge, then drew the line on the cowl. 

 I'll use that as my reference line. Next, will trim the bottom 1/2 up 

 to that line. Will see how well that works tomorrow night. 

 Question to those who used skybolt fasteners for the sides. How thick 

 of an aluminium strip did you use for the side fasteners? 0.050 as per 

 the top strip? 

 Dr Fred. 

 Michael Wellenzohn wrote:

 > --> RV10-List message posted by: "Michael Wellenzohn" <rv-10(at)wellenzohn.net>

 >

 > Guys,

 >

 > I am hesitating to trim the cowling due to the fact that the straight edge method doesn't give me the possibility to make a line along the side. 

 > How did you do it?

 >

 > Michael

 >

 > --------

 > RV-10 builder (engine, prop, finishing)

 > #511

 >

 >

 >

 >

 > Read this topic online here:

 >

 > http://forums.matronics.com/viewtopic.php?p=160067#160067

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

 >

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&g==

 	  Quote: 	

Connect and share in new ways with Windows Live. Get it now!

Jim Berry

Joined: 10 Jan 2006
Posts: 237
Location: Denver

Posted: Thu Jan 24, 2008 11:01 am Post subject: Re: Trimming the cowling

David,



The first layer of tape goes on so that the forward edge of the tape matches the forward edge of sheet metal. Position the cowl. The excess material on my untrimmed cowl overlapped the fuselage by less than 2", so the aft edge of the tape was still visible. The second layer of tape goes on top of the first tape so that the aft edges match. The second tape also overlaps the cowling, with the forward edge of the tape corresponding to the forward edge of the sheet metal. Perfect match. Try it and you will like it.



Jim Berry 

40482

dmaib@me.com

Joined: 25 Apr 2006
Posts: 454
Location: New Smyrna Beach, Florida

Posted: Fri Jan 25, 2008 3:21 am Post subject: Trimming the cowling

Thanks Jim!



David Maib

40559

On Jan 24, 2008, at 1:01 PM, jim berry wrote:






David,



The first layer of tape goes on so that the forward edge of the tape  

matches the forward edge of sheet metal. Position the cowl. The  

excess material on my untrimmed cowl overlapped the fuselage by less  

than 2", so the aft edge of the tape was still visible. The second  

layer of tape goes on top of the first tape so that the aft edges  

match. The second tape also overlaps the cowling, with the forward  

edge of the tape corresponding to the forward edge of the sheet  

metal. Perfect match. Try it and you will like it.



Jim Berry

40482





Read this topic online here:



http://forums.matronics.com/viewtopic.php?p=160274#160274

_________________
David Maib
RV-10 #40559
New Smyrna Beach, FL

ricksked(at)embarqmail.co
Guest

Posted: Thu Jan 31, 2008 7:08 am Post subject: Trimming the cowling

For the last three days I have been staring at the first few steps of fitting the cowling...The plans indicate not to trim the sides but the sides interfere with getting to fit the nose ring. Any tips on the first few steps of the cowl? By using the straight edge method it looks like about an 1/8 or little more needs to come off the inner intake on the top cowl. The bottom doesn't sem to need any trimmig on the outer portion of the intakes. Comments on how those who have completed have done this? The masking tape method really looks like a great way to fit the aft part of the cowl...I just can't get a picture of how Vans wants you to do the first few steps.



Rick S.

40185

Mike Whisky

Joined: 05 Jun 2006
Posts: 336
Location: Switzerland

Posted: Thu Jan 31, 2008 7:40 am Post subject: Re: Trimming the cowling

Rick,



since I just did this step here are my lessons learned.

1.) I had to cut a bit off the outer air intake to get the parts together. However do not cut along to the sides too much. I did that but I guess this will be no problem.

2) I put the two halves together and drilled & clecoed them as per plans.

3) For the further steps I followed the plans. 

I am not done yet but I was irritated because the to halves didn't fit at the beginning and it looked so easy on the plans.



I will try to update my web site www.wellenzohn.net with some pictures tonight.



Michael

_________________
RV-10 builder (flying)
#511

Jim Berry

Joined: 10 Jan 2006
Posts: 237
Location: Denver

Posted: Thu Jan 31, 2008 4:42 pm Post subject: Re: Trimming the cowling

Rick,



Like Michael I found it necessary to trim the inner and outer walls of the air inlet to get the upper an lower portions to come together. I also trimmed about 2" along the side of the upper cowl. Once you have the upper and lower cowl in position(let the sides of the lower cowl overlap the outside of the upper cowl) you can decide where you want the side seams to be. Lay out your chosen line on the upper cowl, cut and sand to a straight edge. Then you can use the masking tape trick to transfer that line to the lower cowl. I failed to mention in an earlier post that I also used the masking tape routine to fit my doors to the cabin top. It is much easier than trimming a little at a time until it comes together.



Don't worry if you take off a little too much at some point. It is easy to build up an edge with a little flox if needed. Also I have seen several 10's where the rivets that hold the piano hinge to the cowling(and/or the paint) have started to crack out. I dealt with that by putting a 2 bid tape over the rivet lines.



Jim Berry

40482

ricksked(at)embarqmail.co
Guest

Posted: Sun Feb 03, 2008 12:50 pm Post subject: Trimming the cowling

I cut the top cowl in today...Guys and Gals I gotta tell you the masking tape to mark the firewall cut is the BOMB!!!! Perfect fit with only a few passes with the sanding block needed. The only thing I did different was to use the tape as a guide to apply a fine pen line that I cut just shy of then hand sanded to that line. I was worried the tape would gum up the cut off wheel. Dremel has a new line of cut off wheels added to their line of products made just for plastic, only metal was previously available. I use two wheels so far and that inclusdes the slot in the bottom cowl, my slot is much long due to the three blade prop...highly recommended these nifty cut off wheels.



Rick S.

40185

---

Mike Whisky

Joined: 05 Jun 2006
Posts: 336
Location: Switzerland

Posted: Sun Feb 03, 2008 11:19 pm Post subject: Re: Trimming the cowling

Rick,



how long is the cut for the slot that you did. I also have a three blade prop and I know I need to cut the slot longer. It works right now because the front gear wheel sits on a box.



Michael

_________________
RV-10 builder (flying)
#511

ricksked(at)embarqmail.co
Guest

Posted: Mon Feb 04, 2008 7:24 am Post subject: Trimming the cowling

I'll measure it tonight, funny I eyeballed the cut after looking at Wayne's RV-10 at Nellis. I should have been gambling yesterday because I hit it right on the money. It is about 4 inches from the front of the air intake.I'll make some .032 panels with nutplates on the cowl to tie it all together and return the cowl to proper strength on the bottom



Rick S.

40185

---

Lew Gallagher

Joined: 04 Jan 2008
Posts: 402
Location: Greenville , SC

Posted: Sun Feb 24, 2008 5:29 pm Post subject: Re: Trimming the cowling

Hey Jim,



Just a follow up to tell you how much I appreciate your tape method.  Today I used it to mark the doors to fit the cabin.  I made the first cut a hair outside the line just in case I didn't get it quite right, but after sanding some, I went right to the line and it's about perfect!  How easy is that!



Thanks again.  Later, - Lew

_________________
non-pilot
crazy about building
NOW OFICIALLY BUILDER #40549
Fly off completed !

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