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Western Canada Wing

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Breeze Through Your Inspections

Tedd McHenry, Editor, Western Canada RVator

We were very fortunate to have Hank Horst, the RAA inspector for Kelowna region, give a presentation at the Salmon Arm RV builders's gathering. Hank spoke for more than an hour, in two sessions, telling us about common mistakes builders make, passing on many valuable tips, and clarifying the role of the RAA. New builders like me found the advice very helpful. I've tried to condense Hank's presentation into this short article. My apologies to Hank for any errors, or important points left out.

RV builders and enthusiasts gather tn Salmon Arm to hear Hank Horst speak.

Rigging

Hank emphasized the importance of proper rigging. If the airplane isn't rigged right, it won't fly right. With many kits, the manufacturer's rigging procedure isn't adequate to give proper rigging. Van's rigging procedures are pretty thorough. But don't leave anything out!

Hank also strongly recommended checking your level for accuracy--as do the Van's construction manuals. Check it regularly, as in every time you use it for a critical measurement. The RV-6 manual gives a good procedure for checking your level in the Bulkhead Assembly subsection of Section 7 (Wing).

Don't use common string for aligning and rigging. Use 12# fishing line. It won't sag, and you can get a more precise measurement than with common string.

When plumbing, set a can of liquid--water is fine--on the floor, so that the plumb bob is in the liquid. That will dampen the oscillations of the plumb bob, the same way a shock absorber dampens the oscillations of your car's suspension.

Jigs

Hank emphasized the same point that Van has emphasized in the RVAtor: the jigs don't need to be accurate, only rigid and stable. Strictly speaking, what we use when building an RV are fixtures, not jigs. Jigs position tools for accurate machining and forming, and so must be very accurate themselves. Fixtures, however, only hold parts in relation to each other. So the fixture must be rigid, to keep the parts aligned, but the fixture dimensions themselves are not at all critical. It might be nice to build a fuselage fixture so that each station is perfectly positioned and level. But, to be certain, you're going to have to measure and fine tune the position of each bulkhead anyway so, other than the satisfaction of doing it, there's no point getting that carried away with the fuselage fixture.

Fuel Tanks

Fuel tank leaks are a vexing problem for many builders. You can test your tank many ways, but the bottom line is: does it hold gasoline? Hank recommends leak-testing your tanks with gasoline. Auto gas is fine. You can drain it into the family car when you're done.

Preliminary testing with air and a balloon is fine, says Hank, but you should still test with gasoline. He related the story of one unfortunate builder whose tanks seemed to hold air just fine but, once filled with gasoline, had five small leaks.

Hank recommends PRC as a sealant, because it flows better than Pro Seal. With better flow, you're more likely to get good coverage in the hard to reach places. Hard to reach places like the back sides of rivets--which you should inspect individually, to be sure they're covered. Dipping the rivets in sealant before setting them is also a good idea. Be sure to seal in warm conditions, too.

Fuel Lines and Filters

Fuel lines and filters often cause problems during inspections. Even worse, they too often cause problems in flight. Hank warned against using paper in-line fuel filters. Paper in-line filters are not acceptable. Regardless of your fuel system, you should still use a gascolator. You must use fuel lines with an inside diameter of at least 3/8 inch, for any homebuilt aircraft.

Hank Horst looks on as Homer Rogers explains some of the many modifications he has made to C-GBQX.

Role of the RAA

The role of the RAA has changed dramatically in the last couple of years, and many people (myself included) are confused about it. Hank puts it simply like this: the role of the RAA is to help builders meet Transport Canada's rules. One of the best things the RAA has done to help builders is to put all the critical rules and references in one Builder's Manual. You can order it directly through the RAA, and Hank strongly recommends that you do. I don't have mine yet but, after seeing what's in it, I'm certainly going to get one.

In a nutshell, the RAA provides inspectors (for a fee, to cover costs), who check your work at critical points during construction, to help you keep on track. Once the final inspection is completed, you still have to satisfy Transport Canada. But with good inspections that won't be a problem.

In closing, Hank emphasized a couple of critical items in the regulations that are sometimes missed by builders.

You must use aircraft-standard materials.
You must incorporate the AD on cabin heaters (details are in the RAA manual).
In-line paper fuel filters are not acceptable.
The fuel shut-off valve must be located such that the pilot can operate it while strapped in.

Hank's presentation was the highlight of the event for me. I hope I've been successful in passing on some of what I learned from it.

This article originally appeared in the October, 1998 issue of the Western Canada RVator.

Please send comments to: editor@vansairforce.org.

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