Skymasters Newsletter:
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SkyWriter
Chartered Club #970
Skymasters R/C Club Newsletter
- June 1998
See Skymasters on the Web at www.geocities.com/~skymasters
President's Message
Hi All,
Well, here I am again, sitting on another product from Boeing at 39,000 feet and actually going to visit Boeing! - Your remaining BOD members are holding our fun get together while I write this according to my watch. Hope they got things all straightened out!
Flying season has now arrived, and several club events will have occurred by the time you get this. Two float flies and our giant event will hopefully all have gone well. I will ask each CD for an update to take up a few paragraphs in my next newsletter. Student night soon returns, and with it the pot luck supper! - Remember that we always eat, but only sometimes fly - Last year during the Tornado that struck our area , we still had a crowd of people in awe and fear of the developing storm right before our eyes under the roof. One tornado struck near I-75 and exit 89 I believe - that was a little close for comfort! (we still had supper that night incidentally!)
Each year, at the beginning of flying season our student population and spectator levels are at their highest. Several people will visit our site for the first time and many will have questions about our hobby and what we do, but will be reluctant to ask questions. I would encourage all of you to take the initiative and become a Skymasters diplomat (no test required) - Think back to your initial curiosity to R/C and remember how amazing it was to you. Share your enthusiasm and good manners and we will continue to get new friends and family for a long time. This will take a little courage on your part to walk up to one of these people, but most of you have soloed, and that took more courage than what I am asking for!
Hopefully, I will have finally completed my One Design by the time you read this and may actually bring it to the first club meeting in May. It will be close though, as I decided at the last minute to add a pilot and instrument panel - Those that know how I normally forgo such work will truly be amazed that I actually am building the panel up from pieces and parts around the shop (don't worry I am not going to actually build a scale ship someday!). I am trying out some new servos in the One Design from FMA, and I'll let all know how they do. So far they are checking out O.K. (I will, of course, use these servos as my excuse if I ever "re-kit" the One Design!)
I always enjoy the first month of flying season, with the abundance of new and shiny ships lining up on the tarmac. Those anxious moments of the maiden voyage make for endless chatter from the peanut gallery behind you. It indeed is a challenge to trim that ship on the first flight as those ailerons you could have sworn were aligned insisted on causing a constant roll, all the while listening to the "coaches" in the audience each simultaneously offering advice on how to keep the ship flying. We definitely learn to process many inputs when we fly! One of my favorite techniques to make my ships zing about on maiden voyages is my continued insistence on having the C.G. to the rear limits - trust me on this one, put it where the designer says to!
This season, I am going to put real effort into learning precision aerobatics. I have no intentions of entering contests (that takes much more time than I have!), but I want to improve my flying, and the seemingly simple task of making round loops and smooth rolls is quite difficult (at least for me). So if you see me actually doing something else other than my normal crazy snap rolls and general boring holes in the sky - feel free to come up to me and offer coaching!
Before I sign off for this month, I do need to answer a question posed by your highly competent newsletter editor, who raised the question on if My Super Stinker looks like the one on Display in Toledo - Not! And finally, I am indeed honored by the anonymous club poet, I just can't figure out if I was insulted!
Hope your balsa stays glued!
Joe Finkelstine
From the Editor…
Welcome to another Skywriter. We have a packed newsletter this month. The meeting minutes will be published in next month's newsletter - I ran out of room! Joe Finkelstine has again provided an article for your enjoyment (thanks Joe!) This time its about Horsepower. I did have to break it into two parts once again; Part 1 is here, and Part 2 will be in next month's issue. We are getting into the busy time of year for flying events; both Skymasters and our neighboring clubs. If you haven't attended our events, come on out. Its fun to participate, or just watch! I am publishing a rolling 2 month list of events in this area. If you are looking for a specific event in the future, give me a call. I'll check the listings I have for you.
As always, send any input to me either to my address (on back cover) or email to GMCardillo@misi.net, or of course see me at the field!
Events of the Last Month
Seven Lakes Float Fly
The sun was out, but so was the wind for our first 1998 flying event. With the wind at our backs, and crosswind takeoffs, it made for an interesting day. We had a great turnout of planes and pilots and a wonderful welcome from the park as always! Many pilots braved the winds and flew. We certainly kept the retrieval boat busy! Many thanks to Prop Shop for donating prizes for this event, and to Chet Brady for once again coordinating the day.
Pete and Samantha Foss starting Sam's Dumas Swamp Buggy at Seven Lakes.
A pair of Schneider Cup Racers at Seven Lakes.
Bald Mountain Float Fly
On Sunday, May 17th, at 10am, what could be called part II of the "Carnage of the Lakes" took place. The Bald Mountain Float Fly went off with few hitches. Unlike the Seven Lakes Float Fly, the wind was far calmer (at 5 to 10 knots), providing for a pleasant day at the lake, with sunshine until the end at 3pm. The event was no cost to the club as the concession stand covered the refreshment cost as well as the pilot prizes! Thanks to Rider's Hobbies as well for donating $40 in gift certificates given away as part of the prizes.
All kidding aside, however, we has 24 pilots attend the event with around 30 planes of various types from the basic Cub to the Seamaster, to the scale birds, such as the Consolidated Catalina and the Brittish akjsf (Terry Overton's Supermarine Stranraer - PHF). No accidents occurred. Many thanks to Al McGee and Wade Wiley for providing the retrieval boats, which unlike Saturday at the previous float fly, had an easy day. Thanks to Steve Fredericks for bringing the club trailer on short notice. Thanks also to Marv Middleton for manning the transmitter impound and Greg Cardillo for his excellent guidance and advice and organization of the event as Contest Director.
Ross Jones
Event Director
(This was the first event Ross has run for Skymasters. I thought he did an excellent job! Thanks again Ross. Ed.)
Bill Leppard's PBY Catalina on a fly by at Bald Mountain.
Fred Johnston working on his Kadet LT-40 at Bald Mountain.
Joe and David Hass brought this unusual Paraplane to the Bald Mountain Float Fly.
Press here for more Spring Float Fly pictures.
Upcoming Programs/Events
Wednesday, June 3: Skymasters Student Nights/Pot Luck Dinners Begin!
Saturday, June 6: Skymasters Meeting, Scripps Road Field 12:00
Saturday, June 6: UFO Swap & Fly, Contact Robert Eckel
Sunday, June 7*: Skymasters Kid's Day, Scripps Road Field
Saturday/Sunday, June 13-14: Michigan Whirlybirds Helicopter 431-434, Contact Roy Dietz
Sunday, June 14*: Harold "Big H" Maseles 4 Stroke and Majestic Flyers, Scripps Road Field
Saturday, June 20: PMAC 4th Annual IMAA Giant Scale, Contact Frank Vella
Saturday, June 20: Indian City "One Design" Fun Fly, Contact Pete Bergstrom
Saturday/Sunday, June 27-28: RCCD 1st Annual Bill Stoner Big Bird, Contact Sam Monteleone
Saturday/Sunday, June 27-28: Indian City Precision Aerobatics, Contact Bob Kane
Sunday, June 28: Midwest R/C Pylon Racing 424 & AT6, Contact Chuck Wooley
Saturday, July 4: Skymasters Meeting, Scripps Road Field 12:00
Saturday, July 4: RCCD R/C Combat, Contact David Wagensomer
Saturday, July 4: Midwest R/C Warbirds Rally, Contact Richard Vukmirovich
Saturday/Sunday, July 4-5: Chesaning R/C Big Bird Fly-In, Contact Greg Brausa
Saturday, July 11: Milan Flyers Air Show, Contact David Gell
Saturday/Sunday, July 11-12: UFO IMAA Fly-In, Contact Gus Kaser
Sunday, July 12: Skymasters Team Fun Fly, Scripps Road Field
Sunday, July 19: Skymasters Warbirds and Scale, Scripps Road Field
Saturday/Sunday, July 25-26: Ribcrackers Open Air Show, Contact Greg Bessette
Sunday, July 26: Chesaning R/C Scale, Contact Greg Brausa
Sunday, July 26: Indian City Air Show, Contact Bill Harris
Saturday/Sunday, August 1-2 PMAC IMAC Pontiac Grand Prix, Contact Tom Wheeler
*See additional information for these events in this issue of Skywriter!
Event info from mailings received, AMRCC, and Michigan RC Flying Times
Skymasters Events
June 3, 1998 (and Every Wednesday through September 2) Student Night and Pot Luck Dinners - Come join us for an afternoon/evening full of flying and food. We're out there rain or shine - "we always eat, we sometimes fly!"
June 6, 1998 Skymasters Meeting at Scripps Road Field - our summer meetings are normally very short. Bring a plane to fly before and/or after! Meeting starts at Noon.
June 7, 1998 Kid's Day - Scripps Road Field, Bald Mountain State Park
A chance for kids of all ages to try flying one of our planes! See flyer in this issue.
June 14, 1998 Harold 'Big H' Maseles 4 Stroke and Majestic Flyers - Scripps Road Field, Bald Mountain State Park
Anything with a four stroke or a majestic flyer - old timers, slow biplanes. See flyer in this issue.
Using Horsepower to Evaluate R/C engines - Fact and Fiction by Joe Finkelstine
Continuing in my desire to write out frequent questions I get asked as an instructor, I now turn to Horse Power. The question(s) I am asked take many forms, some direct, some others hidden a wee bit, but the translation often comes down to which engine should I buy, and which engines are the best. Invariably, the person asking me the question almost always brings up horsepower ratings early in the session, and from the comments I get, I am once again motivated to fill up one of our newsletters. As usual, let me start with some disclaimers
1) R/C engines are a religious issue in our hobby, I will undoubtedly anger a few of you with my opinions, but hey, you are free to write an article yourself!
2) There are several anthology series out on R/C glow and gas engines, they offer interesting reading and go into great detail on engine theory and practical tips. Every hobby store has them, and you can also order several from the backs of our hobby magazines (if your really cheap like me, you can just borrow one from a fellow club member!)
3) Just like my previous articles on airfoils, your engine won't care if you know or understand its HP rating, or what "schnurle" porting is. It will, however, care that you feed it clean fuel, good plugs, correct mixture, and after run oil.
Horsepower (HP) is somewhat of a pet peeve of mine, as I was in the hobby of drag racing before R/C. Like R/C, HP is a frequently discussed measurement (and source of endless arguments) for drag racers.
Let me start by saying that HP is probably the most misunderstood and misused metric I have ever run across involving powered engines. Why do I say this ? - read on
Let's start with what HP means, both with words and (sorry about this) a formula or two. In its most basic terms, Horse Power is a measure of how quickly a system can change its energy from one state to another (sorry, but that was my physics background slipping through!) For example, Horse Power tells us how much capability we have to accelerate a car we are driving. Most of us grew up on hearing Horse Power ratings for cars, and most of us equated "high" Horse Power ratings on car engines with fast cars. Take the following example. Two cars, both weighing 2900 pounds, start out from a standstill, and we want to time how long it takes for each car to reach 60 MPH. Car #1 is a Yugo (I think my Saito 300 could power this thing!) whose engine data shows 60HP, Car #2 is one of my old drag race cars, a Pinto with a 351 Cleveland shoehorned in between the wheel wells, which is rated at 600 HP. Both cars start with 0 energy, from a standstill (only counting kinetic energy here!). After about ½ hour, the Yugo will be at 60MPH. The Pinto, however (assuming I didn't break driveshaft U joints, which was quite common!), will be at the same 60MPH in about 5 seconds. Both cars, being same weight and speed have identical final energy, but the higher Horse Power engine allowed the Pinto to reach its energy state of 60MPH much faster. The Horse Power ratings of each engine were a measure of how fast they could change the energy of the system they were in. For the mathematically inclined out there, Horse Power is proportional to the derivative of the total energy of the system with respect to time (I have to satisfy the technoids out there!)
Given the above story, why pray tell, do I still argue that Horse Power is near useless measure for comparing R/C engines? Well, the story is just beginning, so read on. The problem I have with using Horse Power as a purchase/comparison rating originates from the following:
1) Engine manufactures have several ways to fudge the numbers, and they do, because they know most R/C'ers often use HP ratings as a strong purchase criteria. Don't misconstrue what I'm saying here, I'm not saying the engine manufacturers are lying or misrepresenting the numbers. The engine manufacturers are employing a time honored American political tradition, they are using statistical lies. I'll explain in detail how this is done in a moment.
2) We as R/C'ers, often, don't do our homework thoroughly, when making engine purchase decisions, nor do many of us understand that what turns the prop is torque, not horsepower! - I'll offer a list of things that I use to make my purchase decisions, that I will argue are better suited for most of us Sunday warriors.
Lies and Statistical lies:
Most of us have run into the following situation, or at least heard about it. Someone on TV is asked an opinion on something that is quite controversial. They are asked a question like "should this ever occur" and being the happy little talking head they reply "yes, BUT blah blah blah". The stuff after the BUT is crucial to understanding what the speaker says, but all you see on the nightly news is the yes part, nothing else. (ever see the triple dot … in a written article? same thing, stuff has been omitted). Technically, the report is correct, the person said yes, but as we all know, an entirely different understanding occurs. This is a type of statistical lie (I know, I'm stretching the analogy here, but your newsletter editor, Greg Cardillo, granted me poetic license! (We'll see. Ed)) . Let me explain the myriad of ways I can statistically lie to you on reporting a Horsepower rating. I have to begin with the formula used for calculating Horsepower and it is :
H.P. = K * T * RPM , where
H.P. = Horsepower
K = a "correction" factor - i.e. a number
T = Torque
RPM = Revolutions Per Minute (you know, the number you read on the tach!).
For simplicity, I'll leave units out of the discussion. First off, what actually turns the prop is the Torque from the engine. Torque is defined as a combination of a force multiplied by a distance. The easiest example is the ratchet and socket set in your toolbox. Most of us know, that one way to help loosen a really tight bolt is to increase the length of the ratchet, by using a longer handled version (a "breaker" bar). We are applying a twisting force with the ratchet. The torque the nut sees wanting to spin it off is the product of the force (from your hand) times the distance along the ratchet handle where you hold it . We can increase the Torque the nut sees by using a breaker bar - i.e. it is easier for me to increase the length of where I apply my hand's force, than increase my strength. The end effect is the same, I have increased the twisting force applied on the nut . This same twisting force is what turns our prop, and Torque is what is actually measured on a dynamometer (dyno for all you gear heads out there!).
The "correction" factor K, is actually a number that is calculated (or manipulated) to correct for atmospheric conditions when an engine is run. This number is used because an engine will have a harder time when temperature is high, humidity is high, altitude is high, etc. Actually, the full scale pilots have a related term for this and it is called density altitude. Density altitude takes into account all the above and is the number that full scale pilots must use when referring to performance charts of the aircraft to check out things like, how long of a runway do I need to take off and reach 50 feet off the ground? Theoretically, the correction factor is useful, because it would allow someone to normalize out the effects of weather and altitude of the engine test, but alas, there is room for statistically lying here as well. The correction factor is supposed to normalize all readings to the "standard" altitude. This corresponds to sea level at 59 degrees F, and a barometric pressure of 29.92 inches of mercury. If I wanted to, I could test my engine in a chamber (or make sure I tested on a very cold and dry day) that would make conditions better than this standard and it would help my engine run. Since all I report is the horsepower, I need not bother telling you what correction factor I created. Here is an opportunity for a wonderful statistical lie, and you'll never catch me at it! - Incidentally, this is one of the main reasons that Clarence Lee (RCM) and Brian Lee (RC Report) always report the weather conditions in their engine evaluations - they know this lie well. Brian Lee actually does one better here, he keeps a special engine that he always runs along with the test engine. He records his "control" engine RPM and uses it to normalize the test engine readings. His argument goes that whatever atmospheric conditions exist, they will affect both engines the same, comparing the control engine RPM during the test divided by the RPM for the control engine on the "standard" day, gives him a correction factor that he applies to all the engine under test RPM figures. For example, when atmospheric conditions are better than standard, his correction factor is less than one, so it reduces the test engine output numbers , which "normalizes" his test results to the standard day he defined when he first ran the test engine. I will argue that this method is actually quite good and is one of the few workable ones. (it is not perfect, but it is certainly workable!) The correction factor in the equation is actually not the biggest opportunity for statistically lying though, that title goes to the RPM number in the equation.
Have you ever noticed on the manufacturers ads that they show HP readings at a RPM level that you would never run the engine at? - happens all the time. Look at the H.P. equation again. Ignoring, for the moment, the torque and correction factor, I can jack up the H.P. ratings considerably by spinning the engine faster (assuming that the torque does not fall off more than my RPM increase). This is one of the reasons you will often see the sport engine HP ratings shown at RPM levels that would render the engine a rebuild candidate after about 5 minutes of running. My Saito 90 four stroke, for example had a H.P. rating shown for 14,000 RPM. If I run my 90 at 14K rpm, I will keep general Saito's parts manager happy by keeping him in business. Lets look at an example of this statistical lie in action.
Last summer, I was approached by a student (this is a true one!) who challenged me to as why couldn't he fly his 60 sized trainer with a .12cu. in. car engine he already owned. Both the 60 two stroke and the screaming little .12 advertised the same horsepower rating of 2.1 HP ( don't remember the number actually, but 2.1 will do!). The .12 needed to be run at 25,000 RPM to get to 2.1HP, whereas the .60 reached these numbers at an advertised RPM of about 14,000. The problem for my inquiring student was that he did not comprehend that the torque available from his little .12 would not swing anything near the correct prop for the ship he wanted to fly. The .60 however, would do a fine job pulling the trainer through the sky. His thought was that the .12 being the much smaller engine was obviously more efficient and well made since it needed only ~ 1/6 the displacement to get the same horsepower. Well, I can't fault him for that one, but perhaps I stopped him from starting with R/C cars. The manufacturers are not misrepresenting the numbers, that little screaming .12 put out the horsepower as advertised, and too many of us fall for the trap of just using this number.
See part 2 of this article next month. Joe will share things to consider when looking for an engine, and give some of his experiences with different engines!
Community Events
Harold Reuter and Al Mrock are teaching students at Lake Orion Middle School how to build model airplanes in after school sessions. Approximately 8 students are participating. K.C. Satchell and Greg Cardillo assisted in a flying session for the students, giving each a chance to fly our club trainer from the football field. The Oakland Press ran an article and picture on May 18 covering the flying session, and on May 28 had an article on the talents of Al Mrock and some additional pictures of our flying session!
Hints and Tips - Monokoting
As a follow-up to his program, some answers to commonly asked questions from Vince Pettke:
One comment often heard is that your plane looks great inside, but on a hot day at the field, it bubbles up and wrinkles. Vince's cure for this: Let the plane sit out in the sun at home until the bubbles appear. Take your covering iron outside and shrink it again in the sun!
Another common problem is how to release gases trapped under the covering when covering a solid surface. Most of us have tried a pin, but the resulting hole can often be seen. Vince indicates the pin stretching the covering before puncturing it, contributing to the visible hole afterwards. Vince uses a small (10 cc) hypodermic syringe. The shape of the syringe makes a very clean and 'invisible' pinhole!
Hopefully we can get Vince to share more of his 'secrets' with us! As was evident in his program, he spends a lot of time in preparation work and covering. It certainly shows in his finishes!
Involvement Day Pictures
Craig White drilling a Parking lot barrier
Bob Remer (DNR) installing roofing
Ross Jones manning the grinder for picnic table repair
Jim Schwarz provided the food for Gary Walling (and the rest of us!)
Skymasters Information
Skymasters field is located within the Bald Mountain State Park (see map). State Park Permits are required and can be obtained from the Park Headquarters located on Greenshield Road or at club events. Flying is permitted from 10 AM to 8 PM. The noise limit for 1998 is 95dB at 10 feet - this noise rule is strictly enforced.
Wednesday evenings during the summer is Student Night and there are usually instructors around all afternoon. Student night is also 'pot luck' buffet night so that you can fly-n-feed (though not usually at the same time). Students are encouraged on other days and weekends. It is a great idea to come on Wednesday, meet the Instructors and arrange for more instruction time together. Our Chief Flight Instructor is Pete Foss. Assistant Chief Flight Instructor is Graham Overton.
From June to August, Club Meetings are held at the field on the first Saturday of the month at 12 Noon - a great chance to fly and gossip too! Winter meetings (September to May) are held at Larson Middle School (on Long Lake just east of John R - see map) on the second and fourth Wednesday of the month at 7:30 PM. Show and Tell, coffee and donuts, and model-speak are the order of the evening. Come along - they are fun.
The Skywriter newsletter is sent to all members, local hobby shops and other local R/C clubs. Any and all contributions are welcome, please pass any articles to the Editor. If you know of anyone who may be interested in our hobby (friend, relative, neighbor, colleague or acquaintance) - please give them a copy of this newsletter or a copy of an AMA magazine - it may spark their interest and get them into our hobby!
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