Measurement for fairings etc

prkaye · #1 01-08-2010, 08:59 AM

I'm going to order some upper and lower intersection fairings. Bob at Fairings etc asked me to make a measurement of the cowl contour as per the diagram shown below, to determine the "type" of nosegear intersection fairing I need.
The problem is, I've moved my lower cowl out to the hangar, and don't plan to be out there again till next month. In any case, it will be pain to haul the cowl back just for this measurement.
Question - aren't vans' cowls pretty standard? Shouldn't it be pretty clear what "type" I'll need? My memory/instict tells me that contour is flat and it would be a type 1...
Thoughts?

Radomir · #2 01-08-2010, 09:31 AM

The critical and the *only* measurement that matters here is the "B" measurement. The other one is not very important and curvature doesn't matter as much. On my -7A, Type 2 was closest fit. Bob and I went back and forth as he sent me Type 1 by mistake and that one did not fit at all... You really wanna measure and make sure you get the right one..

You can put a ruler on the bottom of that plate that hangs off of firewall and measure width of the fairing parallel to that plate.. it'll give you a pretty close idea on which one you need.

Worst case, ask Bob to send you both and return the one that doesn't fit

prkaye · #3 01-08-2010, 09:50 AM

Ok, I don't understand. I thought I was supposed to just measure the contour of the bottom of the cowling. How can I perform measurements A or B without physically having the fairing? What am i measuring?

Radomir · #4 01-08-2010, 10:00 AM

"B" measures width of the gear leg fairing in that "direction" as shown on the drawing.. it's NOT the width chord-wise... It's width parallel to bottom of cowl..

fl-mike · #5 01-08-2010, 10:10 AM

Call Bob. Tell him what cowl you have, make a best guess on the style to order. When you get it try it on. If it doesn't fit PERFECTLY, you got the wrong one. Don't cut it! Send back to Bob for exchange until you get the right one. Took me one iteration. Glad I didn't try to make the first style I got fit, as the second one was spot on. (and yes, I did measure first, but I guess I did something wrong.)

prkaye · #6 01-08-2010, 10:19 AM

Quote:

"B" measures width of the gear leg fairing in that "direction" as shown on the drawing.. it's NOT the width chord-wise... It's width parallel to bottom of cowl..

I still don't get it. The drawing shows measurement B being the distance from the gear leg to the bottom aft and of the fairing. This depends on how big/long the fairing is! My cowl has a slot along the bottom (allowing for the 3 blade prop), and I've made a metal cover plate to cover this slot, as per the plans. This fairing should slide up over the gear leg fairing and sit up against the bottom of the cowl, covering the front portion of this slot. What is the variable here that I am supposed to determine with the measurement??

I don't know what you mean by width. The gear leg itself is a standard size, this should determine the "width" of the fairing... ???

Maybe I'll just oder his fairings for the mains and lay-up my own for the nose gear...

Radomir · #7 01-08-2010, 10:44 AM

Quote:

Originally Posted by prkaye

I still don't get it. The drawing shows measurement B being the distance from the gear leg to the bottom aft and of the fairing.

No it doesn't... Take a look at the photo of this fairing and I think it'll help you understand what you're measuring. It measures gear leg fairing (front to back, when measured parallel to bottom of the cowl). Remember, gear leg fairing has to go through that hole. Gear leg itself is not exposed there so it would make no sense to try to measure anything from the leg itself..

I guess the drawing can be seen as confusing due to that "gear leg centerline" line being in the way, but that is not what "B" measures..

prkaye · #8 01-08-2010, 10:48 AM

Now I get it! I looked at Vans' plans and it become obvious what he wants. I think you're right, I can do this by just measuring parallel to the plate suspended below the fuselage. Thanks!

Radomir · #9 01-08-2010, 10:52 AM

Here's one:

http://www.fairings-etc.com/6A_7A_8A_9A_n.jpg

you see the "bottom" of the Bob's fairing? You're measuring the size of that hole where the gear leg fairing passes through.. Obviously it's same as width of gear leg fairing when measured at that particular angle (parallel to bottom of cowl)

prkaye · #10 01-08-2010, 11:57 AM

Thanks guys. Looks like I'm 5.25", which is half-way between type 2 and 3.
Maybe I should just lay this one up myself.
Next question - For the 3-blade prop I had to extend the slot on the bottom of the cowl foward, as per vans plans. But if the intersection fairing is moulded in-place to the bottom of the cowl, this makes the slot-extension unuseable. What have others done about this? Just make a removeable intersection fairing here isntead?