RV Builder's Hotline - July 1, 2006

Soundproofing your RV

(Photo from Bob and Karen Brown's Airplane Building Project)

This week a thread on one of the bulletin boards got me thinking about aircraft noise. Since my RV-7A project is still open to the sky, and has no engine, nor avionics, it's an issue I have done some minor reading on, but haven't really acted on, other than to put some acoustical foam underneath and on top of the brake and fuel lines running along the floor in the forward fuselage. In April 2005, an article in Sport Aviation ("Taming the Noise" pg. 52) examined the impact of placing acoustical foam throughout the cabin, finding -- as I recall -- that much of the work on the side and back of the cockpit had little effect. So I started reading more, and found an article in Britain's Pilot magazine, that detailed the sources of sound that exist in a cockpit: propeller, aerodynamic noise, engine exhaust, and engine vibration. The article highlighted a product called Aero Sound Shield, which is now part of a company called Flight Environments. A glance at the Web site reveals a concentration in production aircraft, not homebuilts.

But back to the issue of the sound itself, for a moment. On the VAF site, Tim Reader of Denver referred us to a forum at Oshkosh last year about soundproofing, with a link to a Powerpoint presentation. Normally I'm not a big fan of Powerpoint, but this one really was helpful. It stressed the two main types of soundproofing solutions -- sound blocking and sound absorption. As you might expect, there are plenty of solutions. Super Soundproofing.org offers something called a soundproofing mat, and provides a step-by-step page of advice. Other builders are in the cut-it-and-stick it club, which also seems to work fairly well with a product at Aircraft Spruce.

One piece of advice I've picked up from various builders: keep an eye -- or an ear -- on weight. Some soundproofing material is quite heavy and can add significant pounds. Consider a more lightweight material. You also want to pay attention to the flammability of the material.

As the Sport Aviation article pointed out, start from the front of the cabin and work your way back. Add as much absorber around instruments and under the panel as you can, while remembering the need for cool air. Use a composite blanket on the firewall, and felt around the glare shield. Use a blanket with felt barrier on the floor. And one more thing: balance the prop and engine and make sure you have the correct engine mounts.

I'm interested in any studies or particular techniques that have been performed by RV builders. Please send it along and I'll be glad to link to it or "print it."

Fly-in photos
Langley fly-in If it's fly-in season -- and it is -- it's photo-taking season. And it is. Last weekend, the hit parade included the Langley fly-in. And, wouldn't you know it? A bunch of RVators showed up. (Philip Mercier's pictures)
Related Link:
Pictures of the Scapoose fly-in (SoCal RV List)

Traffic avoidance options
TCAS unit I am seriously considering an inexpensive traffic avoidance unit (TAU). Around the central Rocky Mountains the aircraft traffic is so low a TAU probably cannot be justified. However, in any traffic pattern near an airport or back east or out west there is enough traffic that a traffic avoidance unit could be a big advantage. (Gene Long's product review in EAA 648 newsletter. PDF)

The new nose fork explored
Among the more interesting threads on Planet RV this week was the one on the RV-List about installing Van's new nose fork (pictured on Bob Trumpfheller's site). Now maybe it's just me not having a machinist's background -- but according to the thread, installing it -- or at least how a few folks approached it -- did not sound like a walk in the park.The thread also said the new fork is now standard.

Tribute to Chris Good
Family and friends said goodbye to Chris Good during funeral services last week in West Bend, Wisc. Chris died in a mishap in Illinois two weeks ago. I asked Howard Kaney, the former president of EAA Chapter 1158 to pen a few words about Chris and he was kind enough to do so. They appear below this paragraph.

"Chris Good was a member of EAA Chapter 1158 in West Bend, WI, where he restarted his passion in aviation a few years ago. Having come to us from England, he had rekindled his interest in aviation through EAA and a relatively new chapter. He became an active member and served the chapter as a board member, technical counselor, and all around volunteer. Chris’s interests in aviation continued to expand, as he became known throughout the RV community for his thoughtful perspective and very detailed insight into build and flying RV’s. His penchant for aviation including achieving his instrument rating, precision flying with the Black Formation Squadron, attending many RV functions and clinics, and even pursuing a dream of having a house and hangar on an airstrip in a warm, southern state.

"Technical and Counselor were very appropriate words to describe Chris. Very knowledgeable, but with a bedside manner appropriate to any experience level, he could build confidence as easily as pass on knowledge to anyone interested in RV’s. As a new builder in the chapter related, “Chris invited me to come to his hangar so that we could talk about the RV project, the tools, and the basic skill needed to start the airplane. During that conversation, Chris also encouraged me to bring along my wife noting that there were times when a second set of hands would be necessary when building the airplane. At the hangar, he spent over two hours showing us how to rivet, bend metal, and manage the frustration that comes along in any new builder’s life. Of course, Chris did this all with his trademark wit and humor. I was reborn as an airplane builder during that visit. We credit Chris with lighting the fire of confidence in both of us.”

"With so many hours of flying in such a short time, Chris was able to experience a quality of life that most of us only dreamed of. His confidence, caring manner, and humor were an asset to the chapter, as well as the greater flying community. His spirit shall serve as an inspiration to all of us."