Oz build SS7

[rosslr]

Making progress on the 'final assembly' and FWF tasks. Now we have the boot cowl organised with the vents, the heater installed to the FW, the computer installed, the panel mounted on the grommets the braces installed for the glare shield.

I think it is time to run the fuel lines from the wing tanks to header tank now - and start the windscreen fitting. I think we will be flying at about the 2 yr mark!

cheers

ross

[Esser]

Awesome Ross!

[jiott]

Oops, you cut out too much of the boot cowl for your vents. Now you have some fill-in work to do. See my 2nd photo on post #559. Don't feel bad, you are not the only one to do this.

[Paul Z]

I concur you cut out too much of the boot cowl for your vents. Attached is a Photo from 703KA. From what I have read and been taught, they will not draw air adequately cut like yours.

[rosslr]

I didn't think that photo would pass without comment! Yes, a few expletives when I realised what I had done ....

Anyway, I have been fixing it up as per suggestions and photo Jim - you did warn me!

My understanding Paul is that the edges need to be sharp for them to work correctly - is that what you were referring to? A bit of body work and hopefully it should be corrected!

Thanks

cheers
ross

[Paul Z]

It needs to look something like this. It needs to extend well in front of the hose mount. If I were doing it I raise the frount edge about 1/8 inch from the boot cowl, and radius it in to act as an air scoop. I wouldn’t flare them out more than 1/8 of an inch. I have done a very rough sketch of what I am talking about, if you need a better description send me a MSG and I’ll do a better sketch. I am planning on making a scoop for mine, just haven’t found the time. As soon as

When I go to the airport tomorrow, I could build the mock up and take a picture and sen it to you. It will be a masking tape, cardboard, & popsicle stick mock up. When I finish working on my plane, I’ll find out how well it works!

[jrevens]

It needs to look something like this. It needs to extend well in front of the hose mount. If I were doing it I raise the frount edge about 1/8 inch from the boot cowl, and radius it in to act as an air scoop. I wouldn’t flare them out more than 1/8 of an inch. I have done a very rough sketch of what I am talking about, if you need a better description send me a MSG and I’ll do a better sketch. I am planning on making a scoop for mine, just haven’t found the time. As soon as

When I go to the airport tomorrow, I could build the mock up and take a picture and sen it to you. It will be a masking tape, cardboard, & popsicle stick mock up. When I finish working on my plane, I’ll find out how well it works!

The NACA design is a low-drag flush air inlet. Putting a lip on it creates drag and should be unnecessary and may well disrupt the vortices the NACA design creates that make it work. It will be interesting to see how it works for you, Paul. I've heard it said that if you really need more air, run the duct up to a hole in the blunt nose of the aircraft, and take the NACA inlet off & use it for cool after dinner conversation... it will probably really cool that off.

[rosslr]

Well, I have parked the Narca vents and will spend some time thinking through how to fix my mistake - I have searched through past files on this site and see I am not the only one to have done what I did! Anyway, I am thinking that I will use some of the fibreglass that I cut out of the bottom cowl to fill in the area I got a little over enthusiastic with. My concern is how to ensure the 'added' cover will withstand the airflow. I am even considering making some alloy inserts.

Apart from this, I got started on the brake lines, did a bit more on the panel and spent a lot of time trying to understand how, and why, the low fuel warning tank is plumbed - a big thanks to Jiott for a great explanation - experimental building is about learning! We are not all engineers but there are a heap of them here who are really generous with the knowledge and opinions. Again, even though my stuff up on the Narca vents suggest otherwise, I strongly advocate to anyone starting off on a kit (and try to practice same) to ask this forum if ever in doubt about how to go about a task.

cheers and thanks
ross

[Paul Z]

No worries, mistakes are Gods way of teaching you new things.

This is how I would repair it.

If you have the piece you cut out bond two popsicle sticks to the outside surface of the piece extending over the edges it. Then take some Hysol Structural Adhesive run a bead around the inside, then press the piece in place, and duct tape to hole until it cures. Remove the popsicle sticks, & duct tape. Then sand smooth.
If you are concerned with it coming out, then sand it all around the outside, apple 1 layer of 6 ounce bi directional fiber glass.

[jiott]

Good repair method Paul. Could also use some SuperFill if necessary to fill in any low spots, then sand smooth and no one will be the wiser. I agree with JR that a raised lip would be counterproductive to the whole idea of a NACA duct. My vents give a plenty good blast of fresh air in the standard configuration.