AIRWAVES

Model Airplane News, Mar 2004

TEXAN POWER

I read with great interest George Leu's review of the Hangar 9 Texan ARF in the February issue. I have been thinking about getting that plane, and his article pushed me over the edge; I already have alternative decals picked out! One question: George wrote that his model flew well with a Webra .60 2-stroke. I'd like to use my Saito .91 2-stroke, but I wonder whether it would overpower the plane. Thanks for your help, and keep up the good work; I enjoy every issue.

Joshua Freeman [email]

Joshua, your Saito .91 will be an ideal powerplant for the Texan; in fact, that model is rated for a .65 to 1.00ci 4-stroke. Although the .91 will be at the higher end of the power spectrum, you shouldn't have any trouble, and can you ever really have enough power? Good luck with your T-6. DC

HAPPY ANNIVERSARY

First of all, congratulations on your first 75 years. I hope to still be a subscriber for another 75 years (at the age of 120!). In the January 2004 editorial, Debra Cleghorn wrote that a lot of material from old issues of Model Airplane News had been reviewed for the commemorative article. Is there much more material than has been published that is stored in a computer file? I would rush to order it; it would be a graphic history of model aviation. Again, happy birthday and congratulations.

Manuel Ortiz Aguilar

Madrid, Spain

Thanks for the trip back in time. Until yesterday, I hadn't purchased a copy of Model Airplane News for more than 25 years. I left RC and flying scale models after the Scale Internats in Ottawa in the '70s. The growing trend toward large-scale and .60-powered, tuned-pipe pattern "bombs" was too much for me and my MG-A sports car transportation. I preferred to fly much smaller models-.19-powered and below. I even had a few photos and construction articles published in model magazines of the day, including Model Airplane News. Reading your current issue, it appears that my interests were more in line with the models that you feature in Backyard Flyer. It was fun to once again read about the exploits of some of the old gang, like Hal deBolt and Maynard Hill. It was also great to see that Nick Ziroli Sr. has hair with white waves just like mine!

Gerry Cole

Longmont, CO

Very well done on your 75th Anniversary issue! It reminded me of special issues of years past-the annuals-that I always very much looked forward to. I am celebrating a model aviation anniversary this year, too. September marked, for me, 50 years of involvement with internal-combustion model airplane engines. (I have been a regular reader of "MAN" even longer than 50 years!) These days, my flying consists mostly of building and flying "sport" RC models.

As I mentioned at the top, I am enjoying the 75th issue very much-excellent job. Keep up the fine work.

F. Gerald Long

Pooler, GA

We're glad you appreciated our Anniversary issue; we enjoyed putting it together and hope that it brings back a lot of memories for everyone. We'll continue to highlight significant articles and issues throughout the year in our Model Airplane News "Classics" column.

All of our research involved thumbing through back issues and taking photos of old articles; only information for the last 10 years or so is available electronically. DC

INVERTED 4-STROKES

I've read several articles on operating 4-stroke engines inverted. The problem of hydraulic lock on starting is obvious and easily overcome. Less obvious, however, is the issue of camshaft lubrication. One gentleman wrote that cam/followers wear out after about one hour of operation.

Shay Pickton

Lafayette, CA

Shay, operating a 4-stroke engine inverted doesn't cause any more problems than running it upright. Four-strokes displace oil in the fuel from the high-pressure combustion chamber to the relatively low pressure of the crankcase. Moving past the piston compression ring, everything gets lubricated, including wristpin bosses, connecting-rod bushings, crankshaft/camshaft ball bearings, cam lobes, lifters and lifter guides-residual oil vents from the crankcase to the atmosphere. A few high-dollar 4-strokes lubricate by inducting fresh fuel and air through the crankcase prior to valving it into the combustion chamber.

Today, 4-stroke engine manufacturers and distributors realize the harm (mechanical wear) that low-percentage-oil fuels can inflict on their product; most recommend at least 20 percent. The new YS DZ 4-stroke engine requires 24 percent. RC and control-line precision aerobatic models have used inverted 4-stroke engines for years and are routinely operated for dozens of hours without problems other than the occasional necessary valve adjustment. For more information on 4-stroke operation and maintenance, see my "Basics of 4-Strokes" article in this issue.

Dave Gierke

GLOW-TO-GAS CONVERSION

In Fred Coleman's December 2003 review of the Flair Products Stearman PT-17, he references his conversion of an O.S. Engines' BGX 3500 to gasoline. The conversion used a "Pro Spark" electronic ignition. There is no mention of this product in the listing of suppliers at the end of the article. Can you please provide a source of this product or a website for additional information and possible suppliers of this product? Thanks for your help.