Radio Control — GIANT SCALE
Bob Beckman
TEMPUS FUGIT. My, how time flies when you're having fun! This issue marks the start of my fifth year writing this column. I wasn't in on the very beginning of the Big Bird movement, but I've certainly been in the thick of it during the explosive growth and development of the last few years. I've been modeling for over 50 years now, and nothing in all that time can compare to this thing we call Giant Scale. And I'm not the only long-time modeler who feels that way.
Time and time again I run into people who, even though they had gotten bored and given up on modeling, are bitten by the Big Bird bug and bound back boisterously.
When I first started doing the column, I wondered where I was going to get enough material to keep it going. That turned out to be the last thing I had to worry about! Every time I turn around, there is something interesting to talk about. So much, in fact, that during the past four years I've written some three dozen articles and a book, in addition to a column almost every month.
Of that new and interesting material, 90% has come from you. A lot of it came from talking to many of you at fly-ins and other gatherings, and the rest from your letters. Most of my column this month will be from some of those letters.
Campbell's C-130
I got the following letter, and some pictures, from Bob Campbell:
"Flew the C-130 Sunday, October 30, 1983. It flies great! Takeoff weight was 204 lb. Had to add 15 lb. to the nose. Flew at Shelly Airport on a 3,500-ft. asphalt strip. Takeoff was super. Rolled 75 ft. and the nose gear came up. Another 100 ft. and it gently lifted off. Climbed out just beautifully! It flies faster than the B-29 on the same engines (four Kioritz 2.4 ci engines).
"We are using four-bladed, 20-8 Clark Air Screws cut down to 18 in. They turn 5,400 rpm. Flew a 10-minute flight. Handles much better than the B-29. Very responsive on all controls. Turns on ailerons like a Pattern ship.
"Landing was great. Eased it down on the mains, held nose gear off about 40 ft., and settled on it for rollout. All in all, a picture-perfect flight. Most amazingly, it needed no trim changes in the air! The B-29 is the same way!
"Spent two days in Pensacola with the Blue Angels, Oct. 10 and 11, as their guest. Got some great shots of their C-130 and mine. Will forward some Navy photos when I get them.
"Have a good videotape of the flight. Having it duplicated, since I already have a number of requests for it.
"Anyway, Bob, I wanted you to have these pictures ASAP."
There has been a lot of controversy about, and, in my opinion, misplaced criticism of "ultra-giant scale" models like Bob's B-29 and C-130. There are times when I think the critics must have great-great-great-grandfathers who condemned railroads because "speeds over 15 miles per hour were certain to be fatal."
Anyway, even though I have no desire at all to emulate Bob's achievements, I admire what he has done and the professionalism he displays in doing it. If the myriad of small-plane R/Cers in this country all took half as much care in preparing and operating their models, all of modeling would have a better safety record.
Fly-Baby experiences (Dale Johnston and George McGinnis)
Two letters covered similar subjects; I'll pass parts of them on together.
Dale Johnston (Saudi Arabia), apparently prompted by my IMAA Fun-Fly Festival comments in the October 1983 column, wrote that he thoroughly enjoyed his first real Giant Scale project, a Fly-Baby Bipe. (Don't count the Citabria — another picture is included here because, being powered by a glow engine, there's plenty of room over the big birds for activity by smaller ones.)
George McGinnis had a different experience with the same engine/plane combination. He built a Fly-Baby Bipe and installed a Q35; it was ever a dog and just wouldn't fly well. He installed a Q50 — what a difference! It is now a beautiful flying airplane. He put the Q50 upright and it fouled the plug because the new P.K. spring starter had the engine very well primed — really wet. As the starter instruction sheet says, it starts first flip every time — that spring is really something.
My Fly-Baby, built of basswood, weighs 22 pounds. I would assume Dale's model weighed less than 22 pounds, which might account for the difference between the two models. Of course it might have been a matter of different expectations on the part of the builders. Twenty-two pounds is well within the range of the Q35's abilities, obviously.
I don't agree with George about the need for mounting the engine upright. It has been my experience that it is very unusual to flood a big banger when starting cold. Usually it's the other way — you don't give it enough prime. And the H&K Super-Starter from PK Products spins the engine through so fast that you get a good hot spark.
George also sent a size and price list for pre-cut basswood that he can supply. Bass is a nice material for Giant Scale: a little heavier than spruce in the same size, but you can use slightly smaller sizes and have the same strength. If you're interested, a note to George will get you the list:
George McGinnis 144 Murray Ave. Goshen, NY 10924
A pro's views
Another letter with a lot of interesting things in it came from Bill Skipper in Greeley, CO. Bill has been a professional airshow pilot, flying a neat-looking biplane that he designed and built for himself. He has also been an R/C modeler for many years. Here are parts of his letter.
"I was interested in your latest comments (October 1983 column) concerning the Ida Grove event... I flew two airshows for nine years, and being an RC flier for many years, I tried to have local RC demonstrations during intermissions, which worked out rather well. But that was about all the mixing we could take... an airshow meets a model meet, and an airshow is an airshow."
With Bill's background I would have expected a different reaction, but he feels that "... models and full-sized birds mix about as well as curd and onions." But this was just the beginning of his letter. He went on to tell me about his modified Nosen Big Stik. The bird is three years old and has been powered with a Q35, a Q50, and now a Tartan ignition twin.
Among other things Bill mentioned that he has installed separate batteries for the receiver and the servos. This is a technique I have advocated for some time. In my opinion, it is the best way to keep servo/wiring glitches out of the receiver. I usually have my aileron servos on cables about three feet long, and I've never had a problem with them.
Disc Loading (DL)
Bill also discussed a concept he calls "Disc Loading," DL for short. DL is like wing loading, but uses the area swept by the prop instead of the area of the wing. Bill's basic point is that for vertical performance, DL should be as low as possible. That seems to make sense, but it raises interesting questions — for example: what is the effect of increasing the number of blades on the prop?
The question of what prop to use has always been a tough one, usually winding up pretty much a cut-and-try process. Maybe this DL idea can be one way to take some of the guesswork out. Any comments?
Tartan Twin Super-Starter and PK Products mufflers
I have made several comments in columns and articles about the H&K Super-Starter. In my opinion it is the most useful accessory item there is for big bangers. The only bad thing I have been able to find about it is that it's not available for all of our engines. The latest addition to the line is a unit for use on the Tartan Twin. The other engines covered are:
- Q35 and Q50 Quads
- Magnum II
- Tartan Twin
At $39.95, plus $1.50 for postage, the Super-Starter is a very good buy.
PK Products has another item for the Tartan Twin. I haven't seen or used it myself, but their set of mufflers sounds useful. The mufflers are cast aluminum and have a channel through the body of the expansion chamber that allows access to the needle valve on each side. Paul Kinney claims an rpm increase over the stock muffler. Price, per set, is the same as the starter. Available from:
PK Products P.O. Box 6226 Hayward, CA 94540
Personal: To Joe in Placerville
I sent your book, but it came back marked "Not Deliverable As Addressed." Send me your address again, and I'll try to get it right this time.
Bob Beckman 8248 Holly Grove Ct. Manassas, VA 22110
Transcribed from original scans by AI. Minor OCR errors may remain.
