RE: Hyde Mounts
[quote]ORIGINAL: xcead Hello all Is there a need for using Soft mounts on a wooden airframe? I've heard they are important on a composite plane Im building one of them, scratch built, 2 M for pattern. Firewall is 3 mm ply and CF on both sides. The cowl will be made of wood too, sanded till round. And reinforced with glass. Engine is OS 160, piped. Soft mounts ( specially Hyde ) are hard ( if not impossible) to find and expensive , here where i live Thanks, I wait your opinion [/quote] Definitely use the soft mount, The noise reduction and vibration reduction give a superior result. I never owned a Hydemount however. They are so simple to make that I make a new one every time I want to adjust something. I am talking the Hyde style strictly. The design is the best around. Somewhere in this site I have a tutorial on making one. It's for the ZDZ 40 cc engine however, dimensions can be adjusted to what you want. I have just completed a soft mount for the 30 cc Syssa gasoline engine which is also set-up with stand offs. But most of mine have been constructed with maple bearers for the engine mounting lugs, which works super and doesn't need any extra reinforcement. Point is that technique is straight forward to learn and worth the trouble. MattK
Posted on: 11/20/2009 8:40 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9268673

RE: 140rx's days numbered?
[quote]ORIGINAL: Rendegade Matt, I see your point having campaigned with an older design with only about 1.8m span (clipped tips) it snaps well, and flies nicely generally but I feel it's too fast. While we're on the subject, I was thinking this morning about drag. I remember reading something a while ago about Chip Hyde using thinner % section airfoils, and using induced drag to slow the aircraft. Now under normal circumstances I'd say ''brilliant!'' however upon closer inspection when you're flying a downline (which I would consider to be a 0°AOA state) you should reduce the induced drag to its minimum level, correct? So this isn't helping is it? Dave, as much as I agree with you, and admire Nat Penton's design work, I just don't think I can handle putting a dorsal fin on any of my planes. At least not as big as his, coolness is still a factor.. [/quote] Renegade, Parasitic drag is always there and that's what we want to get greater since it is acting constantly, albeit still proportional to speed. Larger, thicker wings do this just fine but I simply don't like the flight envelope of a fat wing. I like a rather thin sectioned wing, around 9% so I compensate with more area. Taper ratio of 3:1 really sharpens the LE at the tips which allows effortless snaps and spins, not the initiation but rather the finish. Absolutely no lag On the dorsals/ventrals, Nat pioneered the concept in models some 30 years ago now (maybe a bit less). Dorsals and ventrals have been around for a very long time in fighters. The Tee Can is an offshoot of this device. Only reason it got to be in vogue is because of who had it on his plane. You know, if everyone had one on his plane, then it would be the kool thingie to have MattK
Posted on: 11/18/2009 12:51 AM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9261983

RE: 140rx's days numbered?
[quote]ORIGINAL: Rendegade Dave, while I understand your point, I do have a few questions about your thoughts. I agree on most of what you say, however, while increasing the % thickness will result in a ''body'' more conducive of lift at certain angle of attacks, surely aspect ratio must in fact have a HUGE effect on it, it can't all be side area. My point of view is that having a deeper fuselage for a given length should increase aspect ratio, albeit slightly, and should, (at least in my alcohol fuelled brain, it's 8:00 pm over here) be more efficient. I think this is where Nat Penton's voodoo express was heading, side area in higher aspect ratios, to gain the required efficiency for snazzy KE. This has degenerated into a discussion about aircraft design, or is it an evolution of the discussion? Either way, I look forward to all your views. Oh, and just so you know, I'm seriously considering cutting balsa on a smaller, lighter aircraft, with the deep/skinny styling of a mid-rex. I suppose before I do, I need to do some more research into ''designed in'' drag. I know that some years ago John Roncz was messing with airfoils that would provide low drag at low speed and insane amounts at high speed, (these airfoils were used on the full sized staudacher for all you IMAC loonies). I think if an aircraft can be wholistically designed with this premise, a more constant speed form of aircraft would ensue, with the added advantage of being able to be powered by a more feeble powerplant. At this point I see the design of F3A aircraft as flying drag machines, requiring gobs of power to overcome the inherent drag in the aircraft. Am I trying to redesign the wheel? Am I a Pattern Heretic? Probably. Then again, when you have heroes like Burt Rutan, and Hanno Prettner (remember the calypso?) it's sorta par for the course. [/quote] Fuselages will always be inefficient wings unless you square one up (fuse depth similar in dimension to wingspan). Changing the depth by a couple inches makes no practical difference in drag. Changing width by a couple inches makes no practical difference in drag either. The main source of parasitic drag is the wing. And reduction in this area (as has been the recent trend) reduces that drag. So guys are increasing wing thickness (which isn't a terrible idea but has its shortcomings for enhancing a fuller flight envelope) and/or create a big bucket of drag in the cowl by limiting the exit area. You may recall a model similar to the Smaragd in appearance (forget the name now) by ZN a few years ago that had a very large cowl with two or three large inlets and almost no outlet area. It slowed the rig down somewhat but at the expense of precision....lots of turbulence up front. Large wings are still (and may always be) the key design features that control speed. And contrary to the beliefs of many, with correct design one still gets a fuller flight envelope including snap rolls. I prefer taper ratio of 3:1 specifically for this purpose. My wings are large at over 1100 squares but do not suffer the no snap or spin blues. I want to try a 4:1 taper ratio but haven't found anyone to cut the foam yet. MattK
Posted on: 11/17/2009 12:11 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9260191

RE: can you compensate for weight?
[quote]ORIGINAL: James c harrell I have a Aeroworks 540T Edge. It is rated for a 60 but I found it a little underpowered with a 55 AX. I did some research and found folks had good results with with the Saito 100 on this plane so I went looking. Found a good deal on an O.S.120 surpass II pump and figured I would give it a go. The O.S. is quite a bit heavier than the Saito and the plane has a bad tendacy to roll out when any elevator is applied. It isn't un-controllable and can be countered with a little aileron input. I know or I think this is because of weight so what can I do. Move the CG, weight one wing? I have thought of mixing some aileron with the elevator. I really don't want to do any-thing that will make it worse because right now I can still control it, with some altitude to correct, so first I will ask you guys. What would you do? By the way, I love this engine so I really want to keep her up there. [/quote] Have you checked the simple things first? Such as equal throw of elevators. Also try putting the elevators under load using rubber bands to simulate flight load and then check deflections. Must set your CG correctly. It sounds like a relatively small model and it would be particularly sensitive to CG accuracy when overweight. Wing loading may be so high that up elevator input may be stalling your wing when CG is too far forward. Usually shows up at slower speeds but high speed stalls are also possible with a CG that is too far fore. What's the weight of your edge? What's the wing area? MattK
Posted on: 10/30/2009 10:39 PM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9216594

RE: Newbie to Gas General Information
[quote]ORIGINAL: Bob Pastorello 38. [b]Using Stuff NOT from the Manufacturer[/b] - in general, unless you have a field full of qualified and experienced gas-helpers, make your FIRST gasser install **exactly like the engine manufacturer tells you to do it*** This helps you in several ways....1) you'll be doing what the folks who will WARRANTY the thing have said to do....2) if you have to call them for help, they will know how your system is setup and it will be easier on both of you for troubleshooting....3) sometimes stuff that folks buy as 'add-ons' to make things better, easier, neater, really do NOT, and then as a new user, you have inadvertently placed unknown variables into the ''why doesn't this work?'' equation. [b][i]It is just really easier, the FIRST time, to ''do it the easy way'', and ''follow the instructions'', as much as that advice may seem counter-intuitive to our knowledge and reason.[/i][/b] 39. If you have read this thread this far, please go back to the start and remind yourself of the ''basics''. When things don't go well, most of us immediately begin jumping on ''device or component failure''. The sad truth, and I am absolutely including myself in this, is that the MAJORITY of time it's OUR failure to seek, read, and heed qualified guidance. We're just too proud since all of us have had chainsaws and weedeaters since we were kids. They ''all work the same''...... NOT!!!!!!!!! [/quote] Bob, Have you soft mounted the gassie? It might take care of several evils MattK
Posted on: 10/10/2009 10:24 PM by Author "MTK" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9162709

RE: NEW SYSSA 30CC GASSER MADE IN THE USA
[quote]ORIGINAL: tsyssa its funny that the capt said that....actually...I just snapped a few quick photos...(dont worry only took 3 minutes) I did not even scale them down...so I hope they post ok here... what you see is a few cylinders with pistons in them ready to be mounted as well as a few rear plate assemblies with carbs ready to go.. you will also see the start of the next group of 500 crankcases being machined now. Almost there. We hope to start running engines and packaging them later today...and working through the weekend to get them out. [/quote] Todd, I like what I see. We are still planning to visit sometime in Oct, Ed Alt, Frank Imbriaco and me. These photos remind me of Bob Obbenberger's shop 25 years or so ago. He created the Tru Turn spinner which has become a mainstay in this hobby. I wish you similar success. Have you had a moment to run pattern size props? 18.1 x 10-11 are good ones to start with. There are a bunch of pattern folks who are interested I will bring the ESComposites 40G pipe and Ed will bring other props to try. The pipe stem has a 0.9" OD. Seeing how busy you must be, I hope you can make the time for us Matt Kebabjian, North Jersey
Posted on: 10/10/2009 10:04 PM by Author "MTK" in the forum "Gas Engines"
http://www.rcuniverse.com/forum/fb.asp?m=9162667

RE: Why we don't see pattern planes for gas?
[quote]ORIGINAL: apereira BTW, the same mount design has been in my Temptress 2x2 since 2003, or at least 1500 flights. Every servo is original and has never been re-built.....the doubled rubber simply works great Six years are 2190days and you got 1500 flights?? I envy you.................... What class do you fly? [/quote] SportF3AAMAMasters. You should never envy anyone. MattK
Posted on: 10/5/2009 10:29 AM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9147951

RE: Why we don't see pattern planes for gas?
[quote]ORIGINAL: apereira Gas engines can be used for pattern, but they are not going to be competitive, that's the problem, there is no way gas can compete against top glow or top electric engines/motors in AMA Masters or FAI. To be competitive cost money, at least for know. [/quote] Absolute statements like this one just make me more determined than ever to complete my latest design and get it flying for next season. Planning on the ZDZ40RE F3A w/ tuned exhaust. I guess I have to show you the way. The trick isn't so much the design and gas power.... For me, it's the trying to design in enough lightness and simplicity so that average builders can do the same thing. I have threads on both the soft mount and the wing techniques I used. I may start one on the prop mods I am making. Wood composite props are not only much lighter than the plastic stuff, they are far stiffer. MattK
Posted on: 10/5/2009 12:40 AM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9147298

RE: Why we don't see pattern planes for gas?
[quote]ORIGINAL: petibonum Another option is offered by a new Mintor 37cc gas engine: 35oz without ignition and muffler/pipe, 24lbs of thrust on a 20x8, 20x10 prop. See http://www.mintor.net/pagine/37cc.htm [/quote] As has been with their glow engines, beautifully done. I just hope the gas offering works better then their glow stuff. Is there a price yet? And delivery? MattK
Posted on: 10/4/2009 10:00 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9146903

RE: Why we don't see pattern planes for gas?
[quote]ORIGINAL: highfly3D i don't wish to damage my airframe by installing a screaming gas engine in it i have see people & don't wish to do this they are very far from glow & electric power leave them for Giant scale & 3D fliers.....................i can t compare any gas engine to a glow engine.....................PEACE PLEASE................. [/quote] Soft mounting and tuned exhaust are the order of the day, just like with glow. This is no big deal. Somewhere in this website I have a thread describing how to make your own soft mount. Very lightweight and works great. Look it up. On the other hand, it requires that you know how to build models, not just assembling and packing equipment into ARFies. If you know building, then it is simple enough to do. BTW, the same mount design has been in my Temptress 2x2 since 2003, or at least 1500 flights. Every servo is original and has never been re-built.....the doubled rubber simply works great MattK
Posted on: 10/4/2009 9:55 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9146884

RE: Why we don't see pattern planes for gas?
[quote]ORIGINAL: AAbdu I would love to see a 35% or 40% pattern plane. I know that it wouldn't be legal for pattern or IMAC, but how cool would it be to see like a 126 inch x 126 inch 150CC Integral! I know it will never happen and it is probably a little off topic but I think that would be great [:D] [/quote] No real reason this couldn't be done. A DA150 puts out a terrific amount of power on canister mufflers. A well thought out design would weigh considerably less than the typical 40% IMAC plane. Props are not really available for pattern type performance though. You'd have to carve you own which isn't a big deal actually. Something with around 18" of pitch should work very nicely at the lower rpm of the 150. But it would need to be crafted properly to do any good BTW, a few months ago I watched a video of an electrified 40% IMAC plane which was using a conventional wood prop of appropriate size to drive the crate. It sounded about as noisy as the gas powered counterpart...that's how bad some large props are. That much noise requires a lot of power to generate Another BTW, Ed Alt, Frank Imbriaco and I have been discussing the Syssa 30 cc gas engine. We will try to get to their shop in the next few weeks and bring a few pattern props with us. We will also bring the ES 40G pipe along and play a bit. We'll report in the KFactor probably. Having had considerable experience running Moki 30cc on glow, (and OS and Webra) it will be interesting to see how the engines compare. I have a project going right now and have planned to use the ZDZ40RE F3A engine in it. If the Syssa 30 cc works well, I may reconsider the powerplant. The weight savings is substantial. The ZDZ has superb manners however....the Syssa has alot to live up to MattK
Posted on: 10/4/2009 1:23 AM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9144946

RE: Mean aerodynamic chord
[quote]ORIGINAL: wellss Neutral point based only on areas and moments are only half of it and NOT accurate. One should be using the lift slopes of the wing and tail ( varying with aspect ratio and sweep ). The latter being about 1/2 due to downwash from the wing and the effect of thrust ( destabilizing in pitch when in front of the CG ) is not accounted for. [/quote] Yup I know. It's a good approximation which doesn't take into account the downwash from the wing. Dag the Elder has already made the observation MattK
Posted on: 9/25/2009 5:10 PM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9123736

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder Qute [quote]The wing design allows (requires?) easier cutting of foam from two pieces per panel. Much more severe taper ratios are possible using this simple and effective technique without compromising the foam cutter's capability[/quote] Unqute A pic is enclosed taken from the cutting of 2 pice wing foam. Best regards [/quote] Yup, very nice and easy. Have you flown it yet?
Posted on: 9/24/2009 11:43 PM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9121965

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder MTK Some data and a wire-diagram from design process. Take a look at the wire diagram to locate the NP and CG. All in all a comprehensive tool from Envision Design. More data will be available if wanted! Best regards [/quote] I couldn't see numbers. Photo was not clear, but I trust the numbers work out well?? When are you thinking to start cutting wood and foam
Posted on: 9/21/2009 11:52 AM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9112243

RE: Sebastiano Silvestri at Worlds
[quote]ORIGINAL: Dean Pappas Hi Matt, The contra gearbox ought to cost marginally more than a normal planetary unit. Let's say double ... that would make the gearbox cost under $500; but the $3500 quote is simply a way to tell potential business to go elsewhere. Dean [/quote] YUP....how is the counter rotating twin coming?
Posted on: 9/17/2009 6:29 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9103861

RE: Sebastiano Silvestri at Worlds
[quote]ORIGINAL: cchariandy Incidentally, sweep is normally specified at the 1/4 chord. The wings on the Xigris C2, CPLRs and Silvestri's planes are quite swept and will add lateral stability over a straight tapered wing. The modern designs have added area to parts of the fuse to improve lateral control authority, I'm curious as to why these planes need more lateral stability...I suspect there is an element of ''looks'' in the design. They remind me of 80's lawn darts. I hope all the other designers don't turn this into the latest pattern fashion trend. Colin. [/quote] Not sure what you mean with "lateral stability". Do you mean yaw stability? If yes, more yaw stability is not desired in a pattern model...the modern model (or ancient model) has (had) plenty. What is not wanted is the spiralling air stream. There is an amazing amount of air mass displaced by a 2 meter model to generate thrust. That air mass hits at various undesired spots on the fuse causing torquing that require offsets to the power plant to augment. These offsets and their unwanted effects are what we are trying to reduce/eliminate. The contra rotating props do this quite effectively as Dean and I pointed out earlier. MattK
Posted on: 9/17/2009 6:27 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9103855

RE: Sebastiano Silvestri at Worlds
[quote]ORIGINAL: tIANci This pic shows it probably has a swept back TE. MTK ... contra rotating or coaxial are not cheap to set up, two ESCs, twin motor unit ... I wonder if the advantage is that worth spending for? [/quote] The expense in Not worth it to me..... there are other ways to straighten the spiralling air stream. That's one thing I am working on. But for the person who wants
Posted on: 9/17/2009 12:40 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9103210

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder MTK NP= ((wing area X distance of wing AC behind propeller face) + (stab area X distance of stab AC behind prop face)) / (wing area + stab Area) Your formulae gives NP approx 2inches aft of what i got from my calculations. I use a software that is made by Envision Design owned by Mr. Blair Beron-Rowdon. Mr. Rowdon has written to the editor of Model Aviation magazine
Posted on: 9/11/2009 1:52 PM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9087127

RE: Sebastiano Silvestri at Worlds
[quote]ORIGINAL: Doug Cronkhite The problem is in getting both props setup correctly to give equal thrust. The rear propeller generally has to have a fair amount more pitch to attain the same blade angle of attack as the front prop. Additionally this changes in a non-linear fashion as speed changes. [/quote] That's not a problem...that's the fun of it. But I am not too sure equal is necessary to fly the model much better than the current norm. I'd guess within 70-80% of one another is probably good enuff MattK
Posted on: 8/27/2009 9:40 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9050641

RE: Sebastiano Silvestri at Worlds
[quote]ORIGINAL: 1bwana1 Pretty nice video here of Sebastiano's practice at the Portugal Worlds. Interesting electric plane with counter rotating props. The video was taken by the Spanish team. http://vimeo.com/6174124 Lots of other nice videos from the Worlds also. [/quote] Contra Rotating when on same axis, also known as co-axial. Counter rotating, as in a twin. I am surprised that more don't use this type of power set-up. E-power has made the coaxial set up practical for model use. These set-ups straighten the spiral airstream so much that right or down thrust is not necessary. Simply makes the plane respond to commands in a truer fashion. Many of the appendages we see on these models would not be needed. Of course, if the pilots THINK the appendAGES GIVE AN ADVANTAGE, THEN THEY DO. Then again, maybe Seba Silvestri has the only in with the designer, Romell I believe. Romell's innovations are truly outstanding. MattK
Posted on: 8/26/2009 11:00 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9048263

RE: Composite-ARF Integral, kinda build thread
[quote]ORIGINAL: woodie I think I have determined the performance problem for the P-11 and F-11 sequences is not the Integral, nor the motor, nor the batteries, nor the radio.... :-( Woodie [/quote] Of course....the dreaded LOOSE SCREW IN FRONT OF THE CONTROL. Wish it was easy to tighten that sucker. Just can't seem to get a grip on it MattK
Posted on: 8/23/2009 2:17 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9038035

RE: Designing a new pattern model
[quote]ORIGINAL: Alex Voicu [quote]ORIGINAL: NJRCFLYER2 Very impressive work on this! One suggestion for weight savings is to construct the firewall from 1/4'' cross grain balsa laminated with CF cloth. I use small dowels embedded in the balsa to create the mounting hardpoints. This is very strong and much lighter than a plywood, or CF laminated plywood firewall. The firewall I did for my Integral came out to 1.6 oz. You can do the same for the landing gear mounts. If you really want to save weight in the main landing gear mounts, I recommend studying how Wistmodel designed the Vivat, Prestige and Bravo. There's nothing else out there that I know of that is so light and durable as their system. [/quote] Thanks for the suggestions. The landing gear idea is very ingenious and i'll keep it in mind for the composite version. The wood structure was designed with a hard LG mounting plate and changing it would require a major redesign of the area. For the firewall i need something that's 4mm or 1/6'' thick, so i don't have to modify other parts. Do you think CF laminated 4mm cross grain balsa will work or is it too fragile? Since i'm going to lasercut another firewall, i can test a few ideas. [/quote] 4 mm end grained balsa laminated with carbon cloth on both sides is very strong. For electric, 3 mm end grain is fine. Vacuum bag it as Ed showed to achieve the best contact and highest carbon to epoxy ratio. I also think this is nice work. MattK
Posted on: 8/20/2009 9:38 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=9032306

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder MTK Thank you for your comment. I have played a little with the root cord and how far it shall go out on the wing. The preliminary design result shows improvement for; 1. Pitch Damping Ratio 2. Improvement of lift and CL distribution, greatest lift approx midway out on the wing Thing starts to settle in I believe[;)] Regards [/quote] Dag, that's the point
Posted on: 8/11/2009 9:05 PM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9008878

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder MTK, Some data from design process that is still going on. Wing root 18,7, tip 8 NP 9.25 from LE CG 5.70 from LE that gives 3,55 in front of NP wich is 25% of Cmac @ 14.08 Tail volume 0.705 Moment arm 43.40 Wing loading (oz/sqft) 23,30 Design weight empty 10lb Max weight 11lb Static margin (Cmac) 0.25 Short period Damping Ratio 0.76 Approx stab lift -0.39 Horiz stab
Posted on: 8/10/2009 10:47 PM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=9006445

RE: DUPLICOLOR-PAINT SHOP PRODUCT
[quote]ORIGINAL: F.Imbriaco Has anyone used this new base coat/clear coat lacquer based product ? I saw it on ''TWO GUYS GARAGE''. It comes pre-mixed in a variety of colors-don't know if it would match plastic films or if it is nitro-proof( no problem for electrics, of course). The BIG PLUS is that it can be sprayed WITHOUT a space suit /outside air supply- just use a good respirator mask in your clean garage and you're good to go. The PPG CONCEPT/ IMRON type paints yield good results, but are a serious health hazard without an outside air source .I believe it is available in quarts ,considering that it's gun ready, that seems ok. This lacquer is different than the old stuff which cracked , etc.- it is flexible, can be sanded if an imperfecton happens, recoats are not time limited, and can be buffed. [/quote] Frank, 25 years ago I used to finish in lacquer and polyU clear. Worked well and was light. On occasion however, raw fuel would go through the clear and attack the lacquer If this stuff can be thin and stay opaque, you're in business. And if it's more fuel resistant than old lacquers, even better Matt
Posted on: 8/8/2009 8:54 AM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=8999482

RE: *Aquila by Northeast Aerodynamics*
[quote]ORIGINAL: NJRCFLYER2 Joe, there are a few changes from ''factory stock'' that I can recommend with an Aquila for best performance: 1. Ask John to send you a set of laser cut plywood doublers for the landing gear area. 2. If using a 120AX, use a tuned pipe with a check valve pressure line to supply tank pressure for best performance. I wouldn't bother with a pump, this works quite well. 3. Get a set of CF landing gear. 4. Consider a CF wing tube as well for weight reduction. I don't use one, but you can save some more weight if you think you need to. For reference, the prototype Aquila flew fine with a stock OS muffler and the heavy aluminum landing gear, provided the correct prop was used. A 15x12 did the trick. The performance was adequate for Sportsman, maybe Intermediate if you upped the nitro from the 15% I was using. I later switched to an ES tuned pipe setup on the prototype and of course got much improved performance as a result. When I began flying a production model, it originally had the stock landing gear, but I switched to Bolly CF gear to save some weight. The performance with a 120 AX and an ES pipe is more than adequate for up to Masters. I found that a 17x12N APC cut down to 16 3/8'' provides excellent vertical performance, and all around good handling to manage your pace through the pattern. If you're not into modifying props a little bit, a standard APC 16x10 pattern prop pulls well, but doesn't have the same brakes coming downhill. I'm going to try a standard APC 17x10 as well. Other power options might be something like a YS 140, or an OS 140 RX. You would likely need to add lead in the tail in that case. I just switched mine to a lighter Hyde mount than I had been using and saved just over 2 oz in the nose, allowing me to take out the 3/4 oz of lead I had in the tail. I plan to bring my Aquila to the Meroke RC Pattern Primer on August 22, so you can give it a try then if you're there. I'll have it with me at the Oasis season finale as well. [/quote] Ed, I felt the plane flew fine on the one occasion I got to fly yours. Maybe yours is an extra light copy, I don't know. But the model is large enough to withstand some more weight. I have been surprised by some of the commentary on the model , "...not fit to fly Sportsman...." and such are just plain ill advised. Not to belabor the obvious and putting myself on a limb, have these guys really watched Sportsman lately? From discussions with you, I think that John is open to suggestions. However, poor comments give birth to poor perceptions and these are very difficult to overcome. Personally, a pattern model this size for just over 400$ is a bargain. The only way that's possible is IF you design AND build your own assuming you know what you are doing in building one. Even then, it's a stretch. MattK
Posted on: 8/2/2009 11:00 PM by Author "MTK" in the forum "Pattern Flying"
http://www.rcuniverse.com/forum/fb.asp?m=8985051

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder MTK, Thank you for answer. Re formulae: It is great to check and balance my own work, however there is a small descrapency of no significane i believe. Some decimals have to be included in my own summations before multipliing. Comparing these two gives a difference of less than 1.0 The NP was calculated like this, firt started with straight LE, then end up after
Posted on: 8/2/2009 3:16 PM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=8983984

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder MTK, When you stated a TVC @ 0.6 for your aircarfts i got very curious, maybe to much[8|]. Anyway i will give some key data from my ongoing project (paper work is ongoing) and i hope for your comments on this. All lenght measures in inch, area in sq inch. Geometry: Wing 939sq span 36,6 root 17,70 Tip 8 LE backwards 3 inch NP 7.77 from wing LE in center of aircraft
Posted on: 8/2/2009 9:28 AM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=8983322

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder MTK, Thank you for your answer. I guess you are flying a 2m pattern plane of your own design. Therefore i am interesting in the details from your design asked in previous questions. Reason is that i must say the TVC @0.6 is rather small and i wonder how you acheive this. More or less all ''brands of pattern planes'' have a larger TVC as i can judge
Posted on: 7/31/2009 9:35 PM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=8980161

RE: Mean aerodynamic chord
[quote]ORIGINAL: DagTheElder MTK, Please give us some more info re your TVC @ 0.6 Tail area, moment arm, main ving MAC cord, or root and tip cords. This will make us understand how you design your models. Thanx [/quote] Tail Volume Coefficient, TVC, is a simple calculation of airplane parameters. However it takes some thought to explain the reasons why the parameters work in a particular way
Posted on: 7/31/2009 11:25 AM by Author "MTK" in the forum "Aerodynamics"
http://www.rcuniverse.com/forum/fb.asp?m=8978788