Wild Bill Netzeband's Control Line Capers
February 1962 American Modeler
There are probably precious few people who bother to mix their own fuels anymore, especially since there are so many commercial brews available, and contest fuels are often prescribed by well-established rules. Such was not always the case. Local hobby shops for most people carried only a couple choices (often still the case), and mail order for fuel was not always an option (which it is now for 4 gallons or more). To assist those who wanted a more precise, predictable, and repeatable method for mixing two or more fuel types, Wild Bill Netzeband devised a fuel mixing nomograph to simplify the task without having to resort to algebraic ratio formulas. As a bonus, Ken Bergen's Ilyushin IL-10 profile control line stunter plans for .29 to .35 engines are included.|
Control Line Capers By Wild Bill Netzeband
Since any given condition of model-engine-prop-weather requires a given fuel we are faced with a problem of blending. We can use commercial fuels alright, but probably could do a little better if we had some more variety. In fooling with algebra we are able to proportion mixtures, but to simplify we hit on the graphical solution shown elsewhere. All you need know are the nitro contents of two fuels and you can mix them to get what you need. We've shown Fox fuels since their formulas are on the cans.
Enter on left ordinate nitro percentage in colder fuel of intended mix. Enter right ordinate with nitro percentage in combo's hotter fuel. Connect two with straight line. Two "X" axis scales needed are zero to 10 parts, zero to 100%. Y axis will be up to 70%; oil scale, 20 to 30%. Use chart to determine amount of each ready-mixed Fox fuel in brew of desired nitro content.
Principal is simple, as you put more of the hotter fuel into the mix, the nitro goes up. Top nitro is, of course, the nitro in the hottest fuel. Thus mixing Super Fuel and Hi Nitro we can get from 5% up to 65%. Clear? If you know the nitro content you can add other lines to the graph for them. Locate the cold one on the left vertical axis and the hot one on the right. Connect these points with a straight line and you're in business. Since oil is important, the upper chart aids in determining oil content of final mix. Same principal. Since Super Fuel and Hi Nitro are both 29% oil, no change occurs.
Am asking fuel manufacturers if we can publish the nitro content of their fuels. Will probably draw some blanks, since fuel mixtures are hard (if not impossible) to crack chemically and manufacturers reserve the rights of trade secrets. K&B has already declined to have theirs published since if nitro content is known, a chemist can break it down. In the meantime try this out to get manufacturers recommended fuels in your engine. Watch the nitro over 30% in Combat though. It gets tricky.
Mail Bag. Jim Mears, father of the "Slingshot," mentor of the "Texans" etc., informs that the Lubbock group has finally been recipient of a real flying site. Donated by the city, it includes 10,000 bucks worth of goodies like: a paved speed circle, three grass circles, concession stand, restroom, underground sprinklers (to make the grass grow), fenced parking area, and lights! What, no cover? Oh, yes, 5 acres of precious Texas terra firma. The clubs has been pushing several years for a spot, and the dam sure broke. Luck guys. What's the magic word?
From Down-Under again, John Crombie (Piggyfarmer TR) has more dope on these ETA 29 Mk 6c's. The engine turns out .82 bhp at 17,000 rpm using a 40% nitro blend. The engine turns right close to this on an 8x8 Tornado Nylon. That's about 42-in/oz of torque. The ship he had last month is a B entry. Running solo the job turns 115 mph.
John would like credit given to the Upper HUTT Aeromodelers Bulletin for first publishing his plans. Also, word that combat in New Zealand is 2.5cc (.15) engine, 52 1/2' lines and for friends only. Anyone who'd like to correspond with John, try him at 1 Seaforth Terrace, Karori, Wellington, New Zealand. By the - way the tab is 25c per half ounce Air Mail. In case of doubt, he writes better English than I do. (No remarks, please!)
Any of you other guys overseas who have something of CL interest feel free. Your views are welcomed, here. Was expecting some poison pen letters from the Combat ears, but nuthin. Oh well as the rustler said, no noose is good noose.
Down By The Old Mill Dept. While writing up the Nats found a sentence like "Well, in stunt it was Foxes again." Occurred to me that Foxes it's been for quite a while, so I checked. Since Lew Andrews won stunt with one in 1949, Fox 35's & 29's have accounted for over 80% of the top 9 places in National and International (KOI & Plymouth) stunt competition. No telling how many were used by the losers. Duke estimates that 250,000 "35's" have been sold. Why is a simple question. The low (6) compression engine is set up and timed to develop peak power at 10,000 rpm, and to pull fuel through violent changes in fuel head. S'about it. The engine develops 90% of its peak bhp at 9000 running rich and when the mix is leaned out it steps up gently to 10,000 and pulls. Truly a standard fixture for stunt.
K&B Line Holds Steady. Wondered whether KB intends to continue their regular line of engines now that the Series 65's are rolling. So I asked. Result, these engines are still coming off the line: Torpedo .09; .19, .201; .29S; .35; .35C; .45; .19RC; .35RC; & .45RC. The 15's and 23 were the only ones axed, so when the 29R gets out (probably by now) K&B will offer an integrated line of 13 excellent engines plus the Sea Fury .060 outboard. You can have one of each engine for a paltry $260.30 total.
Wild Bill Strikes Again. Our engine comparison was delayed a couple of weeks ago when the K&B came apart. Let me hasten to add "upon contact with a concrete strip." Your sterling test pilot got overjoyed with himself and started hacking around without thought where he'd put the "E" next. It rigged head-on into the deck. Covering 140 feet every second doesn't leave time for mooning. Only damage to the strip was a 1/4" deep hole. You ever bend a case out of line 6 degrees? To salve my injured ego let me state that since (with proper care) we've made over 50 flights with no errors. John Brodbeck was very kind in replacing everything but the head, so after proper breakin, you'll get your results. Sorry.
Shaky Problem. While doing something else, namely breaking screws, we ran across proof of an item everyone talks about. A vibrating engine mount cuts your rpm. Now we know how much. Engine was mounted on 1/8" rubber pads and screws were only lightly tightened, then locked on the bottom. With the engine vibrating through excursions similar to a profile mount and an unbalanced prop (about 1/8" each way at the prop shaft) the vibrating rpm was 14,000. With the same mount, prop, fuel and NV setting with the engine tightened properly the revs jumped to 15,500. Any questions, mate? Percentagewise this constitutes a decrease of 9.7% which isn't necessary and which could mean 90 mph rather than 100, besides early ash-canning of the model.
Scheive Muzzles .049. Got a sample of the E. H. Schieve .049 Exhaust Collector. Put it on a Cox engine and ran it in the basement at 10:00 PM. Really quiets things, could hold finger over end of stack and throttle very nicely with good response. It cut the power somewhat, but we had the hole lined up with one of the cylinder supporters between the exhaust parts. Try yours lined up with the port. It's a cutie and completely practical, not just a gimmick.
Still's Stuka By Ambroid. We're slowly assembling a Stuka for your edification. In order to do it right, I plan 2 to 3 months before flying, so have patience. The kit and contents weigh 2 3/4 lbs. Everything is either machined or die-cut such as routed blocks, formed push rods and gear, die cut flap, elev and stab ribs, notched and tapered spars, etc. Was hoping that maybe THIS would be the simple stunt ship for inexperienced builders, but cannot say so. It requires the same level of skill as the rest of the contest stunt ships. Ambroid has faithfully reproduced every lint-picking detail used in the original model, which should make Don happy.
Two things jar me: The use of a 4-oz Dmeco Clunk tank cut down to 3-oz and showing a KB.29 Series 61 engine as an alternate to the Fox 25. Where was the last tank like that you saw? And I was under the impression K&B's Series 61.29 was a racer! I realize most stunt designers slim down fuselages and make their own tanks, but doggonit, kits should fit commercially available tanks and hardware. Excuse please, but this is a favorite gripe of mine. Didn't mean to have Ambroid stand the full blast alone, TMP's 3-oz tank should fit nicely.
TR vs RR Results. Thanks to fearless correspondents like Joe St. Marie, Ralph Biddle, Bill & Betty Bell, John Crombie, Bob Emmett et al we now have a pretty fair picture of this controversy. Many thanks.
It appears that there are enough supporters for each event to keep them going along in perfect harmony. TR could use some popularizing, perhaps more favorable publicity, model details in the mags, more enthusiastic contest turnouts, along with some understanding sponsors at the local level. Rules might be revised to eliminate the shut-off requirement. Since they ARE an advantage, let those that have them use them. Maybe, race procedure could be cut down, over-sea's style. Maybe also Proto Speed rules could be improved to require TR fuselage cross section. One model and two engine-tank combos could be used in two events. Team Racing has suffered mainly by having info in the hands of too few. So talk it up.
Danger is the beef with anti-RR folks. Suppose we cut the 6-in-a-heat down to 4 maximum. Maybe place a 125 sq. in. min. wing area to cut out the bombs right away. Only the winners would require processing. Any other safety will come from local running of the races, since safety regs are all there in the book. All you need is to enforce them.
Since they all appear to be firmly entrenched we'd best learn to get along.
More On Guardian. At the time the Guardian article was submitted we hadn't found too many meets. Since then Jim Butler and I have managed 1 and 2 (and vice versa) in several meets. Carrier around these inland climes is building up. With a Fox 40 (Roberts Vari-Speed) we've boosted performance to 92 top with 22 lo still possible. So we're over the 500 mark. Try one?
Thought for the month. A building schedule ... down on paper.
Do yourself now this favor.
When contest season rears its heady;
Your list will show why you're not ready.
Semi-Scale Russian Stunt Model Plans
Posted November 9, 2013