RE: Balancing a canard or tandem wing biplane for initial flight.
Craig-RCU, I think we think alike, logic-wise. Kurt
Posted on: 11/4/2009 12:47 AM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9226862

RE: Penetration
[/quote] Bozarth, Either you get it with what I said or you never will. Showing pitch sensitivity in the lift equation is going to put everyone to sleep and probably confuse things more. [/quote] It's "Kurt." I get the lift equation, and always have. I don't get your use of the phrase "pitch sensitivity" in regards to it. I would think those reading this forum
Posted on: 11/3/2009 11:05 PM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9226659

RE: Penetration
[quote]ORIGINAL: CrateCruncher The added ballast does more than just damp turbulence with it's inertia. It moves the airfoil angle required for level flight to a more reasonable positive aoa and makes pilot inputs to that angle less important. With additional ballast the plane's weight is better matched to the lift and drag forces acting on the airframe. [/quote] What is a "more reasonable positive aoa" and if it were more reasonable, why wouldn't you fly at that aoa all of the time? What do you mean by "and makes pilot inputs to that angle less important?" And "the plane's weight is better matched to the lift and drag forces acting on the airframe?" What are the physics and aerodynamic fundamentals behind your conclusions? I guess I have a very hard time discussing aerodynamics when someone uses such subjectives terms ("more reasonable," "less important," and "better matched"). Thanks! Kurt
Posted on: 11/3/2009 9:42 PM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9226452

RE: Penetration
[quote]ORIGINAL: BMatthews Instead the accepted meaning of penetration for sport power flyers seems to be one that indicates a model that rides through turbulent air in a stable manner. If all of you stop and think about how folks have used the term penetration and read into their statements what they are implying at the time I think you'll find that this is most often the case. I think it was ''stolen'' from the glider guiders and twisted to mean ''stable in wind'' instead of able to cover ground. It's a misinterpretation that's not hard to see. A fast glider coming back upwind will often look like it's on rails as it punches through any and everything turbulent in it's path. Only when it slows down again will it seem to bobble about in any turbulence. A power flyer seeing that and hearing folks say ''WOW! LOOK AT THAT BABY PENETRATE!'' could easily take away the wrong meaning..... [/quote] But let's not attribute this ability to some magical aerodynamic feature called wind penetration. Increased mass flying at a higher speed has higher inertia and momentum, which will reduce the effects of gusts. Now bring on the mythical "dreaded downwind turn" written about so often in RCM! Kurt
Posted on: 11/3/2009 1:27 PM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9225270

RE: Penetration
[quote]ORIGINAL: CrateCruncher [quote]ORIGINAL: Bozarth How is ''wind penetration'' any different from simply flying faster? Kurt [/quote] ''Penetration is in my understanding, the ability to make forward progress (ground speed) in extreme wind [i]while remaining pitch stable[/i].'' Kurt, simply adding power to the plane will not cure the problem of pitch
Posted on: 11/3/2009 11:51 AM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9225066

RE: Penetration
It's not. Kurt
Posted on: 11/3/2009 1:28 AM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9224273

RE: Penetration
How is "wind penetration" any different from simply flying faster? Kurt
Posted on: 11/2/2009 9:39 PM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9223854

RE: 737 near mid air video
[quote]ORIGINAL: k3 valley flyer Since 9/11 any reference to commercial airliners and crashes or midairs etc just isn't a good subject to make light of! The title of the thread offends me not the reality of his photography. I understand it was done as an attention grabber but still in poor taste in my book. A lot of us have kids in the military now and take this stuff to heart. [/quote] You have got to be kidding!!!!!!! You probably are offended by "dead end" road signs. The title of the thread "offends" you? Seriously? "Poor taste" in your book? What book? This is such a great example of how anyone can claim anything is "offensive" to them for any reason they want. I flew in the military for 10 years - what in the world am I to take to heart? I'd be laughing my head off if I weren't crying. My friend told me he disliked his Sig Kadet - I was greatly offended because my uncle was named "Sig" and he died of cancer, and even worse, I was an Air Force Academy "Cadet" for four years before graduating. Can you believe he would say such a thing? Kurt
Posted on: 10/30/2009 5:28 PM by Author "Bozarth" in the forum "Aerial Photography and Video"
http://www.rcuniverse.com/forum/fb.asp?m=9215817

RE: Good looking covering scheme
[quote]ORIGINAL: Eganwp 2. ALWAYS ALWAYS ALWAYS (and I hate when people don't tell others this and they crash it due to orientation issues) use the darker colored covering on the BOTTOM of the plane!!! Eganwp [/quote] Guilty of both. I'm sorry - I just didn't know. Kurt
Posted on: 10/28/2009 8:35 PM by Author "Bozarth" in the forum "Sport Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9210673

RE: New fast airframe in the works
You are confusing the YS with a Rossi! Kurt
Posted on: 10/27/2009 8:32 PM by Author "Bozarth" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=9207470

RE: Good looking covering scheme
A few of mine
Posted on: 10/27/2009 8:03 PM by Author "Bozarth" in the forum "Sport Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9207370

RE: New fast airframe in the works
Yes, the YS 60 SS was a higher revving engine compared to the Long stroke. BUT the SS is a pattern engine, not a high revving racing motor. According to the "Operator's Manual Y.S. Futaba 60F.S/R" the recommended prop was 11x7 3/4 to 11x8. I also have additional instructions printed by Golden Gate Hobbies dated April 15, 1985. It says "For pattern use 11x9 or 10. For turnaround, use 12x8 or 9." They went on to recommend an 11x6 for breakin. 15,000 to 17,000 RPM on a 9x9 is way to high! Especially considering the recommened prop for even the YS .45 is 10x9 to 11x7 with a 10x6 for break in. A short stroke doesn't always mean more RPMs - just look at how a Nelson SS compares to the newer Nelson LS! Kurt
Posted on: 10/27/2009 7:28 PM by Author "Bozarth" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=9207266

RE: New fast airframe in the works
[quote]ORIGINAL: combatpigg A short stroke model engine of good [contempory] design made from quality materials should be able to handle 10,000? If the engine is ruining rods at a low rpm [like 10,000], the pipe must be over-boosting the engine, or the nitro's too high for that big 11x10 prop. [/quote] Agreed. But I was assuming he blew away the 10,000 rpm mark with such a small prop. Maybe he will let us know. Kurt
Posted on: 10/26/2009 11:31 PM by Author "Bozarth" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=9204919

RE: New fast airframe in the works
[quote]ORIGINAL: Yak13 After opening the YS, to my surprise, the brearings are ok, but the rod is done. A friend of mine has a replacement part which I hope he finds, after letting it sit for a couple of decades. Im not sure what could have happened. Maybe a bit more oil would help. I am using 10% nitro, 18% Klotz. Any suggestions? [/quote] I used to run my YS 60 short strokes on APC 11x10 props with Hatori tuned pipes. I don't think they turned much over 10k rpm. My bet would be you severely under propped it and as a result, over rev'd it. The rod is normally the first to go in these scenarios. Kurt
Posted on: 10/26/2009 7:56 PM by Author "Bozarth" in the forum "Extreme Speed Prop Planes"
http://www.rcuniverse.com/forum/fb.asp?m=9204230

RE: FOAM PLANES
Please don't tell this to the pilots that show up to our indoor events! You obviously are not talking about indoor foamies! Now I'm off the indoor fly-in. Kurt
Posted on: 10/24/2009 7:59 PM by Author "Bozarth" in the forum "Electric Aerobatic & Sport Planes"
http://www.rcuniverse.com/forum/fb.asp?m=9199228

RE: AILERON TRIMMING.
Deleted.
Posted on: 10/23/2009 6:30 PM by Author "Bozarth" in the forum "RC Radios, Transmitters, Receivers, Servos, gyros"
http://www.rcuniverse.com/forum/fb.asp?m=9196842

RE: MODEL TECH 2M REMEDY
Good choice. Kurt
Posted on: 10/22/2009 1:09 AM by Author "Bozarth" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9192659

RE: MODEL TECH 2M REMEDY
bourbon, scotch or ambien? Kurt
Posted on: 10/22/2009 1:05 AM by Author "Bozarth" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9192653

RE: MODEL TECH 2M REMEDY
But when does it move far enough back to create flutter on a Remedy? (by "it" I am assuming you mean boundary layer separation?) Kurt Edited to add: We want to see pictures of your Remedy!
Posted on: 10/22/2009 12:34 AM by Author "Bozarth" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9192590

RE: MODEL TECH 2M REMEDY
[quote]ORIGINAL: go vertical the square trailing edges help in preventing flutter ... [/quote] Really? At the risk of oversimplifying the issue: Real F-16s have thin trailing edges, and so do propellers and Q500/Q40/FAI pylon planes. How fast does a Remedy have to go to encounter flutter, and how much faster can it go with thicker trailing edges and not encounter flutter? Will we really enjoy the prevention of flutter on a pattern plane due to thicker TEs? How thick is thick enough? How do we know? Inquiring minds want to know? [8D] Kurt
Posted on: 10/22/2009 12:11 AM by Author "Bozarth" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9192529

RE: FOAM PLANES
Come join us at our next indoor fly-in this Saturday. We have a blast, and most have been in the hobby for 20+ years - and guess what they all show up with - foam planes! No one forces them to?!? The majority also fly on 2.4 gHz and have HD tv's and really small cell phones. I have no idea why? Kurt
Posted on: 10/21/2009 6:57 PM by Author "Bozarth" in the forum "Electric Aerobatic & Sport Planes"
http://www.rcuniverse.com/forum/fb.asp?m=9191697

RE: should expo be used on 1st time trainer?
Not true. You are not applying trigonometry correct at both ends of the pushrod. Kurt
Posted on: 10/21/2009 3:27 PM by Author "Bozarth" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9191262

RE: should expo be used on 1st time trainer?
[quote]ORIGINAL: BarracudaHockey If my car has brakes I'm not going to remove the floor boards so I can stick my feet out to stop just so I can apprecaite brakes later on. If your radio has it, no reason not to use it, though 50 percent is a lot, I'd start between 20 and 30, 20 percent or so will actually yield linear control response and help do away with the natural tendency for the controls to be MORE sensitive around center that a stock setup gives. [/quote] BarracudaHockey - I like your brake analogy! However, most stock setups ARE linear with no natural tendency for the controls to be more sensitive around center. The sinusoidal movement of the pushrod at the servo produces a linear result at the control surface thanks to the radial movement of the surface around its hinge line. Of course I am assuming the pushrod is set 90 degrees at the servo and at the surface control horn, as most setups try to do. 10% of TX stick movement equals 10% of control surface movement. This is my favorite subject! Kurt
Posted on: 10/20/2009 12:56 AM by Author "Bozarth" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9187199

RE: Penetration
[quote] Kurt, you're getting hung up on the sematics of what folks are typing. I'm sure that Jim meant ''if nothing ELSE is changed.....''. Just read between the lines a little, OK? [/quote] BMatthews, At some point we have to be technically specific and accurate (at least I like to be). Too many Old Wives Tales floating around on how and why planes fly. Kurt .......... edited to correct keyword so quote would show as such
Posted on: 10/19/2009 6:33 PM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9186074

RE: Penetration
[quote]ORIGINAL: Jim Thomerson If nothing is changed, the airplane has to fly faster to generate enough lift to fly the additional 1/2 lb. [/quote] But "if nothing is changed" it won't fly flaster. Kurt
Posted on: 10/19/2009 2:46 PM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9185608

RE: should expo be used on 1st time trainer?
[quote]ORIGINAL: Sir Raleigh Of course, this debate can go on forever with no mutual agreement. That's why there's an off/on switch for expo. Try it and if you don't like it, turn if off. Bill [/quote] Bill is wise. Kurt
Posted on: 10/19/2009 3:19 AM by Author "Bozarth" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9184561

RE: should expo be used on 1st time trainer?
Why wouldn't you use expo in a plane that was too sensitive around neutral? I have learned that expo provides the best of both worlds - soft setting around neutral yet retaining extreme throws for aerobatics and slow flight. Why wouldn't I teach this to someone else, or even more, why would I try to convince them that it would help but not to use it until they were more experienced. I dialed in expo on my son's trainer. Who says the manufacture's set up/geomety is the best, and why be mercy to it? I don't need to teach my son how to drive a manual if all of his cars are going to have paddle shifts on the wheel. Same with using a mouse with my computer versus using the control keys. We could go on. The phrase "on the wing" is over-used and meaningless.[8D] Kurt
Posted on: 10/19/2009 1:11 AM by Author "Bozarth" in the forum "Electric Training"
http://www.rcuniverse.com/forum/fb.asp?m=9184405

RE: Penetration
How about this question: You are flying a .40 stick trimmed for level flight and 1/2 throttle hands off. Magically, the plane is instantly a 1/2 pound heavier. Without touching the TX, what will the plane do? Kurt
Posted on: 10/19/2009 12:07 AM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9184276

RE: Penetration
Are we talking about maximums and minimums? Kurt
Posted on: 10/18/2009 11:31 PM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9184183

RE: Penetration
Apples - pick your power. Oranges - pick your pitch. A heavier airplane (with all other variables remaining the same) needs to EITHER increase the AOA or increase the speed to maintain level flight. Just because the plane is heavier, doesn't mean it will automatically "fly slower" as stated earlier. WE get to decide this with one of our primary flight controls - either change the pitch or change the power. And yes, sometimes both are needed. Full scale pilots learn this early on. Pitch and power, pitch and power, pitch and power! To say that a heavier model flies slower than a lighter one because it has to fly at a higher AOA and thus has more induced drag is too simplistic and one dimensional, to say the least! Where to begin! Kurt
Posted on: 10/18/2009 8:50 PM by Author "Bozarth" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9183650