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Fixing Cooling Ducting to Firewall

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MalcolmH

Joined: 10 May 2010
Posts: 15

Posted: Wed May 18, 2011 4:20 am Post subject: Fixing Cooling Ducting to Firewall

The manual states that:



"A single AN3-5A bolt screws the side of the duct onto the inside of the footwell using an MS21047 -3 anchor nut, installed in reverse into the footwell to make it nearly flush".



Can somebody please explain 'anchor nut, installed in reverse' I've searched the Gallery and the forums but have no idea what this means. 



I appreciate that because of lack of access within the footwell the rivet holes for the anchor nut would have to be drilled from the outside. Is this all that is implied?



Kind Regards



Malcolm

davidjoyce(at)doctors.org
Guest

Posted: Wed May 18, 2011 5:22 am Post subject: Fixing Cooling Ducting to Firewall

Malcolm, I think it means that you sink the tower bit of the anchor nut into 

the composite layer, rather than having it stand proud of the surface as you 

normally would - which would produce a protrusion to catch your foot on.  It 

means that only the flange part of the anchor nut + a bit of rivet ( 

preferably the smooth bit) would be above the surface to stick into you or 

whatever floor/sidewall covering you install.

Regards, David Joyce, G-XSDJ

---

ptag.dev(at)tiscali.co.uk
Guest

Posted: Wed May 18, 2011 5:27 am Post subject: Fixing Cooling Ducting to Firewall

Hi! Malcolm

It means that the reverse side of the anchor nut will need sinking into the

fire wall so that the bolt/screws will screw into and any excess threads of

the bolt will also disappear into the fire wall and so absorb the thickness

of the anchor nut. In other words simply turn the anchor not over then fix

it with the pop rivets. I also suggest using a dab of redux into the rivet

holes and finally "pull them down" when it has set.

Regards

Bob Harrison G-PTAG



--

frans(at)privatepilots.nl
Guest

Posted: Wed May 18, 2011 6:50 am Post subject: Fixing Cooling Ducting to Firewall

On 05/18/2011 03:24 PM, Bob Harrison wrote:



 	  Quote: 	
		   It means that the reverse side of the anchor nut will need sinking into the

 fire wall so that the bolt/screws will screw into and any excess threads of

 the bolt will also disappear into the fire wall and so absorb the thickness

 of the anchor nut. In other words simply turn the anchor not over then fix

 it with the pop rivets.


	


That is how it is intended.

But I think this is a bad practice. In normal use, the rivets are just

there to prevent the anchor nut from turning while fastening the bolt,

and to keep the anchor nut from falling out when the bolt is removed. In

normal use, once the bolt is fastened, the rivets are free of load. You

could take let the rivets disappear and nothing would happen.



Now mount the anchor nut in reverse... and in this situation the whole

strength of the assembly relies on these two tiny rivets. If you pull on

the bolt, the load is transferred to the rivets and they are the weakest

link. Compared to the AN-3 bolt, the rivets are very very weak.



So, I did not use this method at all. (In fact, I scrapped the entire

cooling duct, but this is an entirely different matter).



Frans

Richard Wheelwright

Joined: 15 Sep 2008
Posts: 111
Location: Halifax, West Yorkshire, UK

Posted: Wed May 18, 2011 7:29 am Post subject: Fixing Cooling Ducting to Firewall

With some carefull measuring you may be able to drill all the way through and use nut and bolt with large washer on the inside.

 

  and miss the rudder pedal flat surfaces. Job dun.

  

 ====================



 Richard Wheelwright

====================

 



   

From: Frans Veldman <frans(at)privatepilots.nl>

To: europa-list(at)matronics.com

Sent: Wednesday, 18 May 2011, 15:46

Subject: Re: Europa-List: Fixing Cooling Ducting to Firewall



--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>



On 05/18/2011 03:24 PM, Bob Harrison wrote:



 	  Quote: 	
		   It means that the reverse side of the anchor nut will need sinking into the

 fire wall so that the bolt/screws will screw into and any excess threads of

 the bolt will also disappear into the fire wall and so absorb the thickness

 of the anchor nut. In other words simply turn the anchor not over then fix

 it with the pop rivets.


	


That is how it is intended.

But I think this is a bad practice. In normal use, the rivets are just

there to prevent the anchor nut from turning while fastening the  bolt,

and to keep the anchor nut from falling out when the bolt is removed. In

normal use, once the bolt is fastened, the rivets are free of load. You

could take let the rivets disappear and nothing would happen.



Now mount the anchor nut in reverse... and in this situation the whole

strength of the assembly relies on these two tiny rivets. If you pull on

the bolt, the load is transferred to the rivets and they are the weakest

link. Compared to the AN-3 bolt, the rivets are very very weak.



So, I did not use this method at all. (In fact, I scrapped the entire

cooling duct, but this is an entirely different matter).



Frans

Photosha Drallehttp://www.matronics.com/con=================

 [quote][b]

_________________
Richard Wheelwright
G-IRPW
First Flight 24th July 2013

MalcolmH

Joined: 10 May 2010
Posts: 15

Posted: Thu May 19, 2011 6:24 am Post subject: Re: Fixing Cooling Ducting to Firewall

Thank you for all the responses.



I think I understand what is intended now. Rather than reversed, the anchor nut is mounted on the outside rather than inside face. The shank on the bolts provided would be to large in this case anyway (1/4"). Maybe I don't understand?. Wouldn't you also have to use a washer on the inside of the footwell for the rivets to pull onto?



I agree with Frans, this puts load on the rivets holding the anchor nut in place. Not sure that this is a good solution.



I'll try and carry out Flying Farmers idea of using a bolt from the inside.



Thanks again



Malcolm Hendra (Kit 121)

r.collings(at)onetel.net
Guest

Posted: Mon May 30, 2011 12:28 am Post subject: Fixing Cooling Ducting to Firewall

Hi, I felt like you that the anchor nut should be mounted on to the inside 

of the cooling duct, so that's what I have done. Its not a problem just get 

the duct into position and drill right through making sure that centre is 

above the rudder pedal floor.

--

MalcolmH

Joined: 10 May 2010
Posts: 15

Posted: Wed Jun 08, 2011 1:46 am Post subject: Re: Fixing Cooling Ducting to Firewall

Hi, I thought I'd update on progress of fixing the ducting to the Firewall.



What I found is that after positioning the ducting assembly onto the firewall according to the photographs in the manual I indicated the available area for a bolt using a matker pen. I then put an anchor nut in a suitable position on the inside of the ducting within this space (similarly to the previous poster).



I then repositioned and drilled pilot holes into the firwall and what I thought was through into the footwell. Wrong.... I have drilled thorough into the void between the footwell and bottom of firewall. I cant positon the ducting in order to secure through to the footwell.



I checked the initial positioning by offering up the lower cowling and it looks perfect.



I suspect this anomaly is because I have the Classic fuselage and cockpit module/Firweall. I cant find any documentation to support this. I do have the XS firewall forward kit.



So in short the ducting will only be supported by the supplied brackets into the front of the footwell. I suppose I could fabricate some further brackets to support at the sides of the footwell if needs be.



Regards



Malcolm Hendra (Kit 121)

grahamsingleton(at)btinte
Guest

Posted: Wed Jun 08, 2011 3:14 am Post subject: Fixing Cooling Ducting to Firewall

Malcolm

you could put the anchor nut on the outside, (the same side as the ducting, drill the hole slightly larger to accept the boss of the anchor nut) Not ideal but it works.

Graham



From: MalcolmH <mhendra(at)f2s.com>

To: europa-list(at)matronics.com

Sent: Wednesday, 8 June, 2011 10:46:28

Subject: Re: Fixing Cooling Ducting to Firewall



--> Europa-List message posted by:  "MalcolmH" <mhendra(at)f2s.com (mhendra(at)f2s.com)>



Hi, I thought I'd update on progress of fixing the ducting to the Firewall.



What I found is that after positioning the ducting assembly onto the firewall according to the photographs in the manual I indicated the available area for a bolt using a matker pen. I then put an anchor nut in a suitable position on the inside of the ducting within this space (similarly to the previous poster).



I then repositioned and drilled pilot holes into the firwall and what I thought was through into the footwell. Wrong.... I have drilled thorough into the void between the footwell and bottom of firewall. I cant positon the ducting in order to secure through to the footwell.



I checked the initial positioning by offering up the lower cowling and it looks perfect.



I suspect this anomaly is because I have the Classic fuselage and cockpit  module/Firweall. I cant find any documentation to support this. I do have the XS firewall forward kit.



So in short the ducting will only be supported by the supplied brackets into the front of the footwell. I suppose I could fabricate some further brackets to support at the sides of the footwell if needs be.



Regards



Malcolm Hendra (Kit 121)





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http://forums.matronics.com/viewtopic.php?p=342391#342391



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johnfcliff(at)googlemail.
Guest

Posted: Fri Jun 10, 2011 5:20 am Post subject: Fixing Cooling Ducting to Firewall

On 08/06/2011 10:46, MalcolmH wrote:

 	  Quote: 	
		   I suspect this anomaly is because I have the Classic fuselage and cockpit module/Firweall. I cant find any documentation to support this. I do have the XS firewall forward kit.


	


I have recently found the same thing, also with a Classic fuselage and 

XS FF kit.



John Cliff

#0259

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