Airwaves

For years, I have searched for plans to build a balsawood model of the PB4Y-2, with an 80- to 100-inch wingspan. Can you help? Building this model has been a lifelong dream, ever since I flew in one as combat air crew during the Korean War.

RICK SHAW

Custer, WA

You're right, Rick, the Privateer would make a super model We're seeing more and more multi-engine planes at fields these daysespecially as the popularity (and reliability) of gas engines and electric motors are causing these models to live longer.

I can't help you much with a kit, however. Jack Stafford Models sells a B-24 kit in the size you're looking for, and you could fairly easily modify it into a PB4Y-2. The fuselage of the PB4Y-2 is 7 feet longer and obviously, you'd have to rework the Liberator twin tails into the Privateer's tall and proud single fin. The other details (e.g., side gun turrets) wouldn't be difficult to model, but the kit would kick start the process for you. For more information, contact Jack Stafford Models, 383 W Chicago Rd, Coldwater, MI 49036; (517) 279-9380. LM

ASTRO MINI-CHALLENGER

A few years ago, AstroFlight produced an electric sailplane modeled after the Challenger. I purchased one of these "Mini Challengers" and was very pleased with it. Unfortunately, I have destroyed it and AstroFlight no longer manufactures this kit. I've heard that a company in Canada may still be producing it. Do you know who now makes this kit, and how I might contact them?

JOHN VEALE

via email

You heard correctly, John. Stuart Pearce, owner of Spirit of Yesteryear, is now producing the Mini-Challenger as well as other Astro planes such as the Viking. He also sells Leisure old-timer kits, which are used by a lot of electric flyers to compete in AMA electric competitions. Give Stu a call; I'm sure he'll be happy to hear from you.

Contact him at Spirit of Yesteryear, 40 Holgate St., Barrie, Ontario L4N 2T7, Canada; phone/fax (705) 737-0532. LM

MULTI-BLADE PROPS

This might be a stupid question, but I can't seem to get an answer from my local hobby shop. I am new to this part of R/C and am just curious why (for the most part) they use only two-blade props, instead of three like on the full-size counterpart-the Corsair, for example. I am building the Top Flite plane with a Saito 150 engine. I don't think torque would be a problem, but am still curious. Any help would be appreciated. Thanks for your time!

MIKE UNDERWOOD

via email

There are no stupid questions, Mike. The reason we use two-blade props is efficiency! In fact, a one-blade prop would be better than a two-blade. Because prop blades operate in the wash of the blade ahead of them in the arc, the more blades you have, the closer they are to one another and the less efficient they are at turning torque and rpm into thrust.

The reason high-powered, full-size aircraft started using multi-blade props was ground clearance. To get enough blade area to absorb the power of Pratt & Whitney radials and Rolls Royce engines, they needed multiple blades. They couldn't mount a large enough 2-blade prop and still have sufficient ground clearance.

Presuming you can sacrifice a bit of power for style and scale accuracy, a four-blade prop would look really great on your Corsair. Typically, you'll need a prop with a slightly smaller diameter than the two-blade prop recommended by the engine manufacturer.

P-38. FOREVER

I really enjoyed the article reprinted from Flight Journal magazine on flying the P-38 in the September 1997 issue of Model Airplane News. These types of articles are of tremendous interest to me, and I wouldn't mind if you did more of them. I know in the past you have printed quick histories of fullsize aircraft but to tell you the truth, I already have quite a bit of that sort of stuff lying around the house. On the other hand, I do not have many articles on pilots' impressions, so any articles on actually flying the aircraft, as in the P-38 article, would be greatly appreciated.

The P-38 is one of the most underestimated aircraft of WW II. Our fascination with Allied aircraft such as P-Sls, Spitfires and P-47s, with a possible mention of the Corsair and Hellcat, certainly relegates the P-38 to a footnote in most of our minds. We'll often start considering the opposition's aircraft shortly after going through the short list of Allied fighters, without even remembering the P-38. Oddly, though, the P-38 destroyed more enemy aircraft than any other Allied fighter; with a record like that, you would think it would have gotten more recognition than it has over the years.

The P-38 excelled at low-level dogfighting in the Pacific, briefly mentioned in the article-a task for which it was not designed. The P-38 also had an excellent record in the Mediterranean theater. Opinions of its success in the European theater were mixed because of difficulties with the manual turbo controls early in the war. The addition of automatic turbo controls later in the European theater roughly coincided with the introduction of the Merlin-powered Mustang, and so goes history-or our remembrance of it.