Erfolg Posted January 26 Share Posted January 26 Does any one know what the incidence between wing and tail plane is/should be. This is the polypropylene electric version with the 46" (approx1.2m) wing? Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 27 Author Share Posted January 27 Does anyone have access to Naca 0018 cd/AOA plot looks like. I am particularly interested in the stall AoA (the approx., ignoring scale effect). Also the max lift drag AoA. I have an idea what it might be, although I seem to make more mistakes these days. Plus the guy I used to discuss these things with, before I did anything, is no longer with me. Quote Link to comment Share on other sites More sharing options...
Arthur Harris Posted January 27 Share Posted January 27 If you are referring to this, isn't it built in? If you are referring to a different plane, I'd like to see it as I like Chris Foss's designs. 1 Quote Link to comment Share on other sites More sharing options...
Arthur Harris Posted January 28 Share Posted January 28 @leccyflyer I don't get the joke. The thread is about the small wot4 e wing incidence. What am I missing? Quote Link to comment Share on other sites More sharing options...
Geoff S Posted January 28 Share Posted January 28 IIRC, Erflog has built a replacement fuselage for a foamie Wot4 and, presumably, is trying to get it to fly like the original. Just guessing. 1 1 Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 28 Author Share Posted January 28 There is a reason, in that my wot 4 suffered massive damage to the body when it crashed, essentially doing I believe is called a half Cuban roll. Then in the vertical part of the loop, it kept on going absolutely vertically down, no amount of bending the tx stick altered the trajectory. The result was a body beyond repair. I decided to rebuild a body out of ply. I carefully drew around the remains (after gluing together), then designed (although that is pushing the concept) the internals. With new metal geared servos. Anyway the first flight did not go well with the best club flyer doing the honours (not me). Since then I have been carefully checking everything I can think of. My last check has been the wing/tail plane incidence which is at 5 degrees (just slightly less), where the stall AoA is 15 degrees for Naca 0018 (0010 & 0012) I believe. It would be good to know what the relationship is with a unsullied model, in case I did not do the reassebly of the bent fuz well. the first picture is with new body. 1 Quote Link to comment Share on other sites More sharing options...
leccyflyer Posted January 28 Share Posted January 28 22 minutes ago, Arthur Harris said: @leccyflyer I don't get the joke. The thread is about the small wot4 e wing incidence. What am I missing? Your post gave me a chuckle. It reminded me of questions and answers like "Does anyone know what is the wingspan of a Hurricane?" "Well, it's the distance between one wingtip and the other wingtip." Quote Link to comment Share on other sites More sharing options...
Geoff S Posted January 28 Share Posted January 28 What was the problem on the maiden? Not so bad that your modified Wot4 didn't get down in one piece, I assume. Quote Link to comment Share on other sites More sharing options...
Arthur Harris Posted January 28 Share Posted January 28 18 minutes ago, leccyflyer said: Your post gave me a chuckle. It reminded me of questions and answers like "Does anyone know what is the wingspan of a Hurricane?" "Well, it's the distance between one wingtip and the other wingtip." I didn't know the context; all I saw was this OP: Does any one know what the incidence between wing and tail plane is/should be. This is the polypropylene electric version with the 46" (approx1.2m) wing? Which you must admit was mystifying, lol! Quote Link to comment Share on other sites More sharing options...
Arthur Harris Posted January 28 Share Posted January 28 9 minutes ago, Geoff S said: What was the problem on the maiden? Not so bad that your modified Wot4 didn't get down in one piece, I assume. A question I would like the answer to, as well, as I'm thinking of getting one as a step up from the Riot. Quote Link to comment Share on other sites More sharing options...
Philip Lewis 3 Posted January 28 Share Posted January 28 I don't know the answer, never owned one, but 5 degrees sounds way too much for an aerobat, I would have thought 1 degree would be much more like it. Quote Link to comment Share on other sites More sharing options...
Caveman Posted January 28 Share Posted January 28 Erfolg, look here on Outerzone at Mike Delacore’s Rival https://outerzone.co.uk/plan_details.asp?ID=10431 The wing/tail incidence is zero. GDB 1 Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 28 Author Share Posted January 28 It did survive the first attempt. It stalled out in climbing out. Philip I have also set a previous model at 2 degrees, from memory. A pushy cat built with a non standard wing using Naca 0009. Given that on the 0-0 line symmetrical sections generate no lift, where as the so called flat bottom sections are generating lift with a 0-0, AoA, at often -5 degrees, I now wonder, if that is the reason that the Wot 4 takes of so quickly, climbing out steeply. Hence the question, hmm, what is the standard Wot 4 AoA. Quote Link to comment Share on other sites More sharing options...
PatMc Posted January 28 Share Posted January 28 Erf, 0 - 0 incidence does not equal 0 - 0 AoA. Quote Link to comment Share on other sites More sharing options...
Geoff S Posted January 28 Share Posted January 28 31 minutes ago, Caveman said: Erfolg, look here on Outerzone at Mike Delacore’s Rival https://outerzone.co.uk/plan_details.asp?ID=10431 The wing/tail incidence is zero. GDB Actually, according to the plan, it's 1 deg positive. Nevertheless, much less than 5 deg, which does seem a lot to me, but I'm no aerodynamic expert. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 28 Author Share Posted January 28 (edited) That is useful to know. I now suspect that I did not straighten the fuz out. I now have something to see how it can be done, conveniently, or the easiest. I will initially look at 2 degrees, whilst also considering 1 degree. I guess the reason being is that for a trainer type, you want the fuz pretty much level, when trimmed to fly at a reasonable speed, with little elevator trim, requiring some up. At the same time inverted flight requiring little down elevator to keep the nose up. The thick symmetrical section with a really well rounded LE provides the good characteristics at the stall, and when changing the pitch quickly. Edited January 28 by Erfolg Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 28 Author Share Posted January 28 A bit of light relieve, not related directly to the thread. At present I am playing "Halo 4", there is a sequence where you are required to fly down a tunnel/valley (the Sci-Fi type). The tunnel obviously, as a game, has slots to get through, obstructions within the tunnel, air locks that are closing and something's that fall into the tunnel. For us modellers quite easy, except that our down is up, and up is down it is when something suddenly gets in the way requiring a pitch correction, then I instinctively put in the opposite to what was required. I tried altering the controller button option, but did not seem to work when in the game. Now back to my calculator which I do not think I have/had touched in some +20 years ( for sine calc). Quote Link to comment Share on other sites More sharing options...
Geoff S Posted January 28 Share Posted January 28 I still use the Frank Castle's 4 figure tables I've had for 60 years! I find the trig functions easier and more certain in printed form - I rarely use the log tables, but still get my slide rule out occasionally - it hasn't ever needed new batteries in a similar amount of time 🙂 Quote Link to comment Share on other sites More sharing options...
Peter Jenkins Posted January 28 Share Posted January 28 On 27/01/2024 at 15:31, Erfolg said: Does anyone have access to Naca 0018 cd/AOA plot looks like. I am particularly interested in the stall AoA (the approx., ignoring scale effect). Also the max lift drag AoA. I have an idea what it might be, although I seem to make more mistakes these days. Plus the guy I used to discuss these things with, before I did anything, is no longer with me. I'd use between 0.5 and 1 deg. 5 deg is far too much and would need a very tail high attitude to fly level. 2 deg is too much. 1 Quote Link to comment Share on other sites More sharing options...
kc Posted January 28 Share Posted January 28 The easy way would be to find someone with same model in good flying condition and put an incidence meter on it! Various designs for homemade incidence meters and some commercial ones. It is also possible to put a piece of balsawood, ply or card against a fuselage side and copy the fuselage outline ensuring a portion is paralell with the tailplane. It is a most popular model so someone must have one for you to take the data from. My recent experience with an UglyStik type model might be of help. I built an 'own design' sort of mid size between Ugly Stik and the smaller Liddle Stik without all the fancy aileron curves and weird fin. My model has a "Trainer 60 " airfoil (from Profilli) which is blunter than the equally thick but visually sharp pointed Ugly Stik airfoil. I lengthened the nose for electric. Flew a few times over the years but not really satisfying so kept as a reserve model. None of my regular flying pals flys the same mode so I couldn't get a second opinion. Brought out recently and flew a few times then a club member said it looks as though it has negative incidence. I said " no it's exactly like an Ugly Stik or Liddle Stik which has zero incidence". All my pals convinced me it looked as though it had negative incidence so I went home and got a scalpel and cut off 1/16 inch off rear wing seat which gave it about 1 degree positve ( visually ) Result next flight it flew much better! I went home and rechecked every Ugly Stik type plan online and they all seem to have zero incidence compared to tailplane. So my experience is that 1 degree (approx) works well with my plane while everyone else finds zero works well on Ugly Stiks which have a slightly different airfoil. Try 1 degree positive with your Wot4 replica. Quote Link to comment Share on other sites More sharing options...
Erfolg Posted January 28 Author Share Posted January 28 I have beeb considering the option you have put forward, I decided on this current course of action, because I have not been to our field for some + months, the weather here has been so bad. My own method is a home made type of measurement process, using spirit levels, bits of wood an card. I will post a picture of my ad-hoc set up, not suitable for field use. Quote Link to comment Share on other sites More sharing options...
Robin Colbourne Posted January 28 Share Posted January 28 Does this page help? NACA0018 Polars Quote Link to comment Share on other sites More sharing options...
Geoff S Posted January 28 Share Posted January 28 If you have a smartphone, then there are applications for levels that work well. I've had a Robart Incidence meter for years and find it useful for checking biplanes, particularly the top wing, which sometimes seems to hang in mid-air with minimal reference to the rest of the model 🙂 Quote Link to comment Share on other sites More sharing options...
Graham Bowers Posted January 29 Share Posted January 29 I'd suggest working through a trimming process, if one has the inclination 😉 This is the one I use. https://ita.bmfa.uk/wp-content/uploads/2023/07/Basic-Trimming-for-Aerobatics-27-07-2023-v1.pdf Quote Link to comment Share on other sites More sharing options...
Engine Doctor Posted January 29 Share Posted January 29 Your test pilot should be able to diagnose the fault ie to much or too little incidence. Then simply pack the LE or TE with balsa shims until it flys correctly then go home and build it in by adjusting the wing seat. Simple on an electric model as no oil contsmibation to worry about. 2 Quote Link to comment Share on other sites More sharing options...
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