{"id":8144,"date":"2021-08-07T12:14:46","date_gmt":"2021-08-07T16:14:46","guid":{"rendered":"https:\/\/volareproducts.com\/blog\/?page_id=8144"},"modified":"2021-08-07T12:14:46","modified_gmt":"2021-08-07T16:14:46","slug":"how-to-better-flying-through-record-keeping","status":"publish","type":"page","link":"https:\/\/volareproducts.com\/new2024\/how-to\/how-to-better-flying-through-record-keeping\/","title":{"rendered":"How-To: Better Flying Through Record Keeping"},"content":{"rendered":"

Two questions:<\/strong>\u00a0 1) do you want to improve your flying? and 2) do you like facts and figures (data)?\u00a0 If you answered “yes” to both of those, read on.\u00a0 I will share what has worked for me.<\/p>\n

Side notes:\u00a0 a) this is the article I probably “should” have written for the NFFS Symposium and b) I don’t claim that any of this is original – I stand on the shoulders of innumerable modeling giants, including Don DeLoach and William McCombs – I just applied their work to my situation and modified it as it fit me.\u00a0 But maybe it can help you, too.\u00a0 Last side note:\u00a0 this is likely to be a LONG article, not intentionally, but necessarily, so be prepared.\u00a0 I’ll try to keep it on the simple side and I won’t get into “science”; so pretty much anyone can apply what is here.<\/p>\n

BACKGROUND<\/strong><\/p>\n

In my real world life, I have always been working with numbers and calculations.\u00a0 My first professional training was in metrology (precision measurement) at the primary standards laboratory for the USAF.\u00a0 This lab is one step below the National Institute of Science and Technology, the organization that standardizes and maintains all of the scientific units that this country uses.\u00a0 I routinely measured and calculated values to 1 millionth of a unit, sometimes 1 billionth of a unit.<\/p>\n

Secondly, I’ve always been attracted to working with computers.\u00a0 Computers are really great calculators and they take so much of the drudgery of calculations out of the process.\u00a0 No more scribbling on paper, erasing mistakes, and so on.\u00a0 I am pretty much self-taught in spreadsheets, databases, CAD drawing, and so on.\u00a0 So it just came naturally that I apply measurement and computers to the Free Flight hobby.<\/p>\n

As I have mentioned several times, my modeling hobby has two “eras”:\u00a0 “before” I took my 12 year break and “after” (present time).\u00a0 “Before” I built what I liked and kept little data.\u00a0 I did keep records of my victories – date, location, model – but that was about it.\u00a0 And when I drew up plans (pencil and paper, first), I just eye-balled things and used general practices (like h-stab sizes at 120% scale, CG at the spar, and so on).\u00a0 There was lots of TLAR – That Looks About Right – trial and error, and (of course) fun.\u00a0 Between the mid-80s and 1999, I had flown in a lot of local events in Cleveland and Flint and several large events in Geneseo and Muncie.\u00a0 I had moderate success, winning my first kanone in 1990 and amassing 75 before the break.<\/p>\n

But, as I related to someone the other day, I did everything by the seat of my pants.\u00a0 I rarely knew what my models weighed (ironic since my career was Mass Measurement – what things weigh), and while I did keep records I mentioned, there was virtually nothing on rubber or props, or any real data.\u00a0 And if I needed thrust adjustments, I would reach down and grab a piece of grass, or a stem of grass – whatever looked right and fix it (albeit temporarily) – this was long before the Gizmo Geezer nose button (which I use on everything, excepting the lightest Indoor models and NoCals).\u00a0 Note that accurate thrust settings are also critical, but outside the scope of this article.<\/p>\n

When I came back to the hobby, I still did most of that (well, all of that), but I wanted to get better.\u00a0 And just remembering and guessing what worked for various models wasn’t good enough.\u00a0 I remember a question being asked online regarding “how long do your rubber motors last?” or something like that.\u00a0 I think it was Don DeLoach that answered 2 or 3 flights.\u00a0 I scoffed to myself – I used a motor for MONTHS, several contests, and MANY flights.\u00a0 I even thought that I was on a better track because I was “successful” and could get much more out of a motor.\u00a0 (Ha – “much more” was really much less!)<\/p>\n

I remember when Don DeLoach took the top honors at Geneseo after I returned (2012 FAC Nats?) and shortly after published his “My Approach to Rubber Scale <\/span>Flying” (find it HERE<\/a> in the FAC Library).\u00a0 I realized that I was just a babe in the woods.\u00a0 I needed to start doing things differently and I started to keep better records.\u00a0 In 2016, I went to Don’s annual Indoor contest in Colorado Springs.\u00a0 Don was nice enough to put me up for a couple of nights – and – he demonstrated the value of winding to torque.\u00a0 Now I understood why my motors were lasting for months – I wasn’t hardly using them and I was leaving so much power on the table.<\/span><\/p>\n

Enough chit-chat; on to the important stuff.<\/p>\n

APPLICATION OF INFORMATION<\/strong><\/p>\n

If you have read this far, I will assume that you really are interested in how to make your models fly better.\u00a0 So, I will also assume that you use John Koptonak’s “Ten-Step <\/span>Trimming <\/span>Process <\/span>for <\/span>Rubber <\/span>Models” (again, find it HERE<\/a> in the FAC Library) – or something very similar.\u00a0 There are similar articles in places like Bill Warner’s “Hey Kid…” series in the old Model Builder magazines and I think there is something in Don Ross’ book “Rubber Powered Model Airplanes”.\u00a0 Regardless of your source, I am sure they all reference (even obliquely) the CG of the model.\u00a0 This is a critical piece of information that everyone uses, knowingly or unknowingly, to get their model to fly.\u00a0 You need to know the CG of the model if you expect success.<\/span><\/p>\n

But how do you know the CG?\u00a0 In my “old days” experience, it could be found in one of two places: 1) on the plan (rarely), or 2) the generic “at the spar” or “at 1\/3rd of the wing chord”.\u00a0 “Balance at the spar and give it a toss” was often the advice that was given.\u00a0 And if the CG was on the plan (rarely), it was usually placed there following the same advice.\u00a0 Here is my bit of advice (for what it’s worth): THIS IS NOT GOOD ENOUGH, NOR CORRECT.\u00a0 I won’t go into the how’s and why’s – just read Don’s article mentioned above, or read McCombs’ book “Making Scale Model Airplanes Fly”.<\/p>\n

I started calculating the CG to every model I draw up, whether is it my design or some old tried and true model.\u00a0 When you see a CG shown on one of my plans, you can be sure that it was CALCULATED using the Tvo<\/strong> formula that McCombs developed.\u00a0 By the way, the Tvo<\/strong> value tells you how much “influence” the tail has on the model in relation to the wing area and what distance the tail is from the wing.\u00a0 As I said, I calculate this for every potential project I work on – one thing it will tell me early on in the design process is if my horizontal stabilizer is too small.<\/p>\n

For the Tvo or CG formula, you need to know three pieces of data:\u00a0 Wing Area, Tail (horizontal) Area, and Tail Moment. Consider a rectangular wing and tail – simply multiply Length (span) times Width (chord) and you will get the Area.\u00a0 Then measure from Wing Leading Edge to Tail Leading Edge for the Tail Moment – simple!\u00a0 However, tapered wings or elliptical tips make this much more difficult for the modeler.\u00a0 Plug those numbers into the CG formula and you get the CG location in the percentage of the wing chord from the leading edge.<\/p>\n

CAD makes things easy for me – I can draw the outlines and use a built-in tool that measures area.\u00a0 And I can draw a line from wing-to-tail and read the length of that line to tell me the Tail Moment.\u00a0 On non-uniform wings and stabs (tapered or curved in some fashion), you cannot just measure from leading Edge to Leading Edge to find the Tail Moment; you need to find the Average Chord on each and measure from there.\u00a0 And you need to apply the CG value, again from that Average Chord.<\/p>\n

Again, computers can take some of the pain out of this process.\u00a0 You do not need to memorize all of these formulae, you can keep them in a spreadsheet.\u00a0 And spreadsheets are great in that they will do all of your calculations for you, including calculating the average wing chord value.\u00a0 I have created a spreadsheet that tracks these values for every model design I am working on, past, present, and future.\u00a0 There are over 160 designs on this spreadsheet today and I add another every time I think I might be interested in doing a new plane.<\/p>\n

The value in this to me (besides my semi-obsession with tracking data) is that I can add to this information with flight experience.\u00a0 Initially, I use the data to design for better flight characteristics.\u00a0 Then I build and test the plane.\u00a0 And when it is proven in flight, I record the model weight and the successful prop and motor combination.\u00a0 THEN, when I start a new design I can compare wing areas of past models and predict what prop\/motor combos might work well.\u00a0 And here’s another thing…<\/p>\n

I have often told interested modelers that building and flying Sport models will teach you a lot about model flying – and all of that information can be applied to the harder-to-fly Scale models.\u00a0 So I can cross over successful Sport model information to potential Scale models.\u00a0 Of course, this is not an absolute cross reference, but it gives me a place to start.\u00a0 I have used the success of some models, like Embryos and 2-Bits, and applied that to 18″ and 24″ Scale models.\u00a0 Generally Scale models will be heavier and might need slightly different prop\/motor combos, but crossing these categories will get you close to where you need to be.<\/p>\n

Another piece of data that is very useful is the model weight (in grams).\u00a0 When you divide the weight in grams by the wing area, you get Wing Loading in grams per square inch.\u00a0 This is also a very useful tool in predicting model performance.\u00a0 The smaller the wing loading value, the less work the motor and prop have to do.\u00a0 If they have less work to do, they can be smaller.\u00a0 And smaller motors weigh less.\u00a0 This is absolutely critical to Indoor modeling, but if you “build in lightness” into Outdoor models, your overall performance will increase.\u00a0 Keeping track of weight allows me to create target weights for future models and if I can stick to that, I can get decent performance from that new model.<\/p>\n

So what about actual flying?\u00a0 I don’t forget that – it needs to be measured, too.\u00a0 During flight testing you might need to fine tune the prop size and motor to get optimal performance.\u00a0 And then (remember how I described my “old days”?) you need to record this AND record winds AND record torque used AND record performance observed under these conditions.\u00a0 This will allow you to predict future performance based on past performance.\u00a0 Recording these values can be tedious and distracting during competition, but if you have done this homework during testing, then you can just use the information for reference during competition.<\/p>\n

Now I will show you how I record all of this.<\/p>\n

SPREADSHEET and NOTEBOOK<\/strong><\/p>\n

SPREADSHEET<\/strong><\/p>\n

Here is a screenshot of PART of my 160+ spreadsheet.\u00a0 I am sure you can’t read it right here, but if you click it you can see the larger version.<\/p>\n

\"\"<\/a><\/p>\n

 <\/p>\n

Data is entered in the BLUE columns tagged “Measured and Input” and results are in the GREEN columns tagged “Calculated”. Columns on the right were added to track weight, wing loading, prop and rubber.<\/p>\n

The colors on the model name are for me – they reference which models I produce as kits (green) and which are in the works (yellow) and other designs I have considered, but not developed (no color).\u00a0 Also, I separate models by FAC Category:\u00a0 NoCal, Peanut, Scale, Old Timer, Embryo, JetCat.\u00a0 I feel that all of these models have category-specific constraints.\u00a0 While Peanuts and larger Scale models are all Scale, I feel the smallness of Peanuts means that I should keep comparisons withing the Peanut size.\u00a0 On the other hand, as I mentioned above, I have used Endurance models to predict requirements of Scale models of similar size.\u00a0 This is not a one-for-one relationship, but is a rule of thumb comparison that gets me on the right track.<\/p>\n

By looking at the wing area column, you can see which models are larger and therefore “might” have better performance.\u00a0 Note that this is NoCal and it has a small problem – I do not distinguish between Indoor and Outdoor NoCals.\u00a0 That could be an issue if I want to compare models (I feel Outdoor NoCals need to be built heavier than indoor NoCals).<\/p>\n

Note that ABOVE the Tvo column, I have entered 0.600.\u00a0 This is a value that is a predictor of a stable model.\u00a0 Basically, if the calculated Tvo is less than 0.6, the design might be less stable – basically, the tail is too small.\u00a0 Increasing the tail area will raise this number.\u00a0 If I am designing and get some extremely low value (like 0.4), I will increase the tail area to get a better Tvo value.\u00a0 On Endurance models, like Embryo, you can also increase the Tvo by increasing the Tail Moment.<\/p>\n

You can download a copy of my spreadsheet HERE<\/a>.<\/strong>\u00a0 I recommend that you are well versed in Excel and know how to insert sheet rows and copy formulae from an existing row to the new row.\u00a0 The spreadsheet has sample data in each category that are my actual models, built and flown.\u00a0 I have provided a second sheet that shows all of the formulae and explains what they are, in case you accidentally mess up the original spreadsheet.\u00a0 Please do not contact me asking me to fix your ruined data; if you choose to download this, you are on your own – wink.\u00a0 Oh, don’t forget to save your work regularly!<\/p>\n

NOTEBOOK<\/strong><\/p>\n

Keeping a field notebook for all of your models is highly recommended.\u00a0 As mentioned above, you need to tune your model and then repeat successful settings if you expect similar performance.\u00a0 Here are two examples of my note-keeping.<\/p>\n

\"\"<\/a>In this first photo, you can see the records kept for my Yankee IV 1\/2 Wakefield model.\u00a0 It is crude; it is done on the field. It is also incomplete, but it has enough information that I can make a new motor and wind it up to the data provided and expect repeatable performance.<\/p>\n

I started with 2 loops of 1\/8″ rubber, and while I did get a max, I determined that the rubber was not powerful enough.\u00a0 If I recall, I had issues getting the model to always ROG.\u00a0 It is a single-wheeled model and they aren’t the best at ROG-ing, so it needs to leap off the table.\u00a0 I went through 3 loops of 3\/32″, but settled on 2 loops of 3\/16″.\u00a0 It shows that I settled on a torque somewhere between 7 and 9 in-oz (note that according to my Safe-Torque calculator, safe-torque is 8.6 in-oz).\u00a0 Now I know that I need a motor that size and how hard to wind it.\u00a0 Of course, the model is trimmed to handle that torque.<\/p>\n

Here is another page out of my notebook.\u00a0 This time it is for my Cessna Turbo 195 for Indoor NoCal.\u00a0 Before I built this model, my best indoor times were around 2:30-2:45.\u00a0 This model took me from that range, past 3 minutes, past 4 minutes, and finally past 5 minutes.\u00a0 If it wasn’t for keeping track of performance, I never could have done that. \u00a0 In 2021, after 4 years of flying the model in Pontiac, I finally got it hung up in the girders and elected to leave it there after Tom Sova and I tried for awhile to dislodge it.<\/p>\n

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There is another page in my notebook that I use regularly, especially Outdoors.\u00a0 It is a Rubber Equivalent and Safe Torque chart.\u00a0 I will include this as a third sheet in the Spreadsheet linked above.\u00a0 This chart gives me an idea of how I can torque a given motor, especially if I have kept terrible notes (or am just starting on a model).\u00a0 It probably gets the most use when a flying buddy calls out “Hey George, how high can I go on 2 loops of 1\/8?” or similar questions.\u00a0 Note:\u00a0 the right-most column refers to torque readings on my Blahzevich winder, which has units roughly equivalent to 4x in-oz.\u00a0 That is also the source of the 9R torque value in the Yankee IV notes – R refers to Rees winder.\u00a0 My larger models will have an R for Rees or B for Blahzevich – so I know what winder to use.\u00a0 Picking up the wrong winder can have disastrous results – ask me how I know.<\/p>\n

\"\"<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

Two questions:\u00a0 1) do you want to improve your flying? and 2) do you like facts and figures (data)?\u00a0 If you answered “yes” to both of those, read on.\u00a0 I will share what has worked for me. Side notes:\u00a0 a) … Continue reading →<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":8152,"parent":1107,"menu_order":0,"comment_status":"closed","ping_status":"closed","template":"","meta":{"footnotes":""},"class_list":["post-8144","page","type-page","status-publish","has-post-thumbnail","hentry"],"_links":{"self":[{"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/pages\/8144","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/pages"}],"about":[{"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/types\/page"}],"author":[{"embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/comments?post=8144"}],"version-history":[{"count":0,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/pages\/8144\/revisions"}],"up":[{"embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/pages\/1107"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/media\/8152"}],"wp:attachment":[{"href":"https:\/\/volareproducts.com\/new2024\/wp-json\/wp\/v2\/media?parent=8144"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}