FanFacts W
elcome back! As I mentioned last time, this is my favorite time of the year for flying—the days are cooler, with more pow- er for the engines and better lift under the wings, the sky seems to be cleaner and bluer and the winds calmer … what’s not to like? I hope you are having favorable weather and flying in your neck of the woods. I’ve been spending much more time in the office rather than flying; well, some things haven’t changed. The winds have been mostly calm and what little time I’ve gotten at the field has been wonderful, so let’s all hope we have a long and gorgeous fall!
Turbine engines are neat little beasts, but what really goes on inside them? We all “know” that they get hot, but what does it look like inside one of them while it is run- ning? Someone, somewhere in Poland, at an educational setting, designed a glass (Pyrex?) body for a turbine and filmed the startup and run for us to see how things look. Way cool, though I can’t believe the students (and anyone at the flying field!) walked in without hearing protection. I think it’s worth three minutes of your time to watch it on youtube at:
http://tinyurl.com/mdkdhjs. It’s a pretty neat video clip!
Before leaving this subject, some explana- tions for those of you who are not conversant with turbine start-up and operation are in order. The little blue box that the instructor punches to get things to happen is the Elec- tronic Control Unit—aka, the brains. This particular blue box is from Germany, made by ProJet, and is a very capable unit. While a speed control for our edf units controls the voltage to the motor; a turbine ecu controls voltage to the starter motor, voltage to the fuel pump, monitors the ex- haust temperature and rpm, all while keep- ing the values of each in check. The “pop” and puff of flame at the beginning of the start sequence is the instructor reaching down to open the propane bottle; a little bit late in the start sequence, and a little too much propane, which then creates the nice puff of flame. That is quickly blown out as the electronic starter motor begins ramping
PHOTO: JOHN WIEBE’S CLUB MATE
John Wiebe’s own design, 1⁄6 scale Yak-15 comes in for a landing. Hard to think of a jet doing a 3-point full- stall landing, but it’s what this one needed!
up the engine (thanks to the ecu reading the increase in temperature) and feeding kerosene into the combustion chamber as the engine then converts over to running only on kerosene.
That little blue pill—err, box—controls all the parameters to get things running, and keep them that way! While this engine is a propane-start engine, and most new engines come as kerosene start versions, other than the pop and puff at the beginning of the start sequence, the starting and running of them is essentially identical.
Previously, I had mentioned John Wiebe’s scratchbuilt 1⁄6 Yak-15, and all he had was a static photo. Well, beg, plead, beg again and someone finally managed to catch John’s beautiful balsa creation in flight. Knowing how hard it is to get a good aerial shot I can sympathize, but I have them for you to see! It is nice to see neat, one-off projects come to fruition, even more so when they have scale flight characteristics (could you imagine how many would love to install a large tur- bine in this edf and fly time-to-climb flight envelopes that would be the envy of most modern jets?).
John reports he is using an older TJ100, PHOTO: ROD HART
91mm edf fan unit that produces 2400 Watts on a 9S setup, giving very scale-like flight characteristics capable of anything other than unlimited vertical lines; but, then again, the full scale couldn’t either! Thanks for the photos John!
On the subject of older airplanes, I found a website that is devoted to older planes with their actual serial numbers and history It also provides some neat planes to do fur- ther research on! It can be found at:
http://tinyurl.com/ob5wk7y. Having interest in several of the planes (both foreign and do- mestic) listed on the site, I could spend hours (days?) looking at things and thinking about how I would like to design several of them. I think you will enjoy the site! Not only that, but you can do some preliminary research on some of the models you might see at a jet, or warbirds event, like Brian O’Meara’s gorgeous F-84F seen at the Jets over Colorado event this last September. Close on the heels of “forgotten jets” would have to be those that did not make it into production, like the BD-10, the Chich- ester-Miles Leopard, the ATG Javelin, and its current day counterpart, the Textron Scorpion jet.
by greg moore You can reach Greg Moore via e-mail at
jetflyr@comcast.net
PHOTO: JOHN WIEBE’S CLUB MATE
John’s Yak caught chasing and surfing the clouds (above) over Canada. TamJets 100mm fan provides excellent power on 9S, 5000 mAh batteries. Brian O’Meara’s beautiful F-84F (at right) departs at Jets over Colorado. Tail numbers can be looked up on these older planes on the “Forgotten Jets” website listed in the text.
50 DECEMBER 2013
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