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  1. #151

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    RE: F3A Results - SPOILER

    Hey Tony
    Going back re reading what we both wrote
    I never insulted you ! nor intended to. you might have took some absurditys personaly ,But I don`t even know you well enough to insult you.

    I took your attempt at insults, as sly poking, it does not bother me, DO you think I don`t know I`m a poor writer LOL I accept that fact.
    I try to write too fast sometimes don`t proof read , I can barley Type, I`m a mechanic ! (I don`t really have the time to do this) I do have to work for a living rather THEN respond to this

    But I was pulled into a explination into How we built the Bipe , and what was the benefits behind it, what were our goals !
    THAN I was told we didn`t even have any goals.
    Tony, you know darn well I never said Every one would have to fly a YS Bipe to win in FAI ,you know I was making a statement about trends.

    Only from the position of a weak aurgument can someone be offended ,, I was never offended I enjoyed the debate.
    Are my Terms and descriptions sometimes wrong .Yea probably are . But you know full well what I mean. and only concentrated on
    giving me lessons Thats ok too! Dick taught me how to spell a few words a few years Back LOL

    No body has a degree in F3A modeling, and no one was even given a diploma for the same. However like the real world
    you are Judged by you accomplishments ,, Ours this year was Third Place . But the Bipe is a Winner

    I `m not offended or Mad or put off by your remarks or schooling you can learn from anybody and I did learn from this as always.
    I just wish others could feel the same!

    Bryan



    CKAero.net Team YS, Futaba, cool power, Central hobbies, Hyde Mounts, contra, xtreme composites

  2. #152

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    RE: F3A Results - SPOILER

    Tony, you just aren't getting my point. Relax, let others talk. We don't need content police. I enjoy seeing the various points of view. I am glad some people had a good day in those hellish winds at the team trials. I think, at the less, IC proved it is still relevant. There is no need to take everything personally. Mike Hester once had a cute way of describing this, you know. He told Everatt that when the football team went to a huddle, he thought they were talking about HIM

    One thing for sure, there aren't many models out there designed specifically for IC. Maybe that will change. Hope so.

    Brian

  3. #153

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    RE: F3A Results - SPOILER

    Bryan,

    Here are a couple of things you said very early on,

    I can tell you this, there will be a mass migration back to Glow for the simple fact that Glow power has the advantage of throttle flexibility. there is no denying this .

    I`ll take that bet!
    The only smoke that will betray you is the one showing the "spiral slip stream" or coming out of a speed controler!

    We could always raise the weight limit! so your airplanes make weight with the HEAVY packs.

    You may not have been trying to insult but the end result was that you did. Then when I made some comments I got buried by the glow posse. I could have gone into more things, like the comment that glow has better low end torque. Again, the science would show you how incorrect that statement is, but we're not believing science anymore.

    With this I'm happy to let it drop and move out of here. Again, great job to you and Brett for making another team. I wish you only the best!
    TonyF - Team Horizon, Team BJ Craft, Team Contra Drive, Neu Motors
    2010,2009 US Masters Champion,2011 Masters Also-Ran

  4. #154

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    RE: F3A Results - SPOILER

    Brian,

    Believe me, I got your point. I took nothing personally until it became personal. And you were certainly one that made it very personal.

    Again good luck to the team! As I said before, I think all it's members make it one of the strongest ones I have ever seen!
    TonyF - Team Horizon, Team BJ Craft, Team Contra Drive, Neu Motors
    2010,2009 US Masters Champion,2011 Masters Also-Ran

  5. #155

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    RE: F3A Results - SPOILER

    Hi,
    I think it's fair to say that this 'goose is cooked'.

    Brian

  6. #156

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    RE: F3A Results - SPOILER

    I think there are too many Brians on this site

    Tony, If thats what offended you I don`t know what I could have wrote differently! and I think it pails in the comparison of insults LOL
    I think for the most part there was some learning here, I was not trying to Cook any Goose,, I was just defending my positions however poorly I did it.

    However I have had more request to trim airplanes this last week than I have had in the last few months, Including one from you Brian some times I think My good nature is being taken advantage of

    Bryan
    CKAero.net Team YS, Futaba, cool power, Central hobbies, Hyde Mounts, contra, xtreme composites

  7. #157

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    RE: F3A Results - SPOILER


    ORIGINAL: TonyF

    I could have gone into more things, like the comment that glow has better low end torque. Again, the science would show you how incorrect that statement is, but we're not believing science anymore.
    Tony, Bryan has said many times and in many more forums than this that he doesn't always use the proper technical terms, and his spelling and grammar are terrible. What Bryan refers to as torque may not necessarily be torque under the scientific definition, but he did a sufficient job in explaining what he meant. Yet, you keep harping on those types of mistakes and trying to use them to prove a fallacy in his explanation. I don't know too many guys who own a dynamometer to actually measure the torque produced by the electric and IC motors we use. Much like the lack of a truly science-based R&D design process in F3A, it's just too damn expensive. Fly what you like. Fly what feels good for you. But don't come in here and urinate on Bryan's accomplishments just because he can't communicate his findings to your satisfaction.

    So, as long as I'm here I'm going to bring up something that's been eating at me that you said: wings don't produce lift in a downline. You're right, from your myopic definition (force that opposes gravity), lift is not being produced in a downline (not much anyway). Do you think that the wings stop performing the same aerodynamic function just because they're pointed at the ground? No. There will be, for lack of a better term, a "horizontal lift" component in the downline. Maybe I should call it drag? Maybe thrust? We've all seen the diagrams in the flight training manuals showing the 4 forces on the airplane during flight, but that only applies to horizontal flight. Do the wings actually produce lift according to your definition in a downline? You bet, but not much. The "lift" being produced in a downline used to be the induced drag from horizontal flight. It's just not enough to oppose the thrust from the motor and gravity.

    Bryan's methods have sought to find a good balance between all the forces acting on an airplane in all attitudes, without cheating by adding a mix. For the most part, he's done it. His methods can't fix all airframes, but they can get them close enough to reduce the pilot's workload. That's why Brett pushed so hard to have that bipe ready for the Team Trials. That's why Brett was able to take an airplane he only had a handful of flights on and make the team. There were many questioning whether or not Brett's decision to fly the Alferma was the right one. His dad and I both expressed our concerns (not to Brett of course) as we chatted during the rain delay on Wednesday. Brett showed us it was the right choice.
    mjfrederick AMA 275874 NSRCA 4134
    Hebert Competition Designs

  8. #158

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    RE: F3A Results - SPOILER

    From the point of view of an AMA pattern pilot and ARF consumer, it would seem that some exciting new products may come our way in the future: AJ's Proteus for the electric flyers; a new "nitro" airframe or two for the YS set if YS is to make a comeback; a bipe or two, an Alferma perhaps? Return of retracts? And just maybe a purpose built airframe for Contra Drive to see if that design has yet more to offer / potential to reach. All will compete for our hobby dollars, as the pattern fashion world turns. I am excited to see what wins and what is offered for sale as the designs develop over time and find their way to market. The aftermarket for winning designs seems to be the real prize right up there with bragging rights so in a sense, the real contest is just beginning (the battle for our bucks)! Good luck for the new designs, Ilook forward to the new stuff as well as the excellent effort of our fine US team in 13!
    Good Flying! Dana
    4449NSRC AMA

  9. #159

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    RE: F3A Results - SPOILER

    mjfrederick,

    You use such a crude term as "urinate", even when all I have been doing is praising Brett and Bryan for making the team. That is simply untrue and is insulting.

    You don't need a Dynamometer to know that an electric motor will always have more low end torque then an IC motor. It is simply the nature of the beast. As soon as an electric motor starts to spin it is making nearly full horsepower. So it will always beat the IC motor in low end power. Just a little more of that science stuff.

    I have no idea what you could mean from "horizontal lift". But wings are not producing any significant amount of lift in either an upline or a downline. They are of course still producing drag. But since they are not producing lift, it is not induced drag, but it is parasitic drag. So if you hypothetically removed them, the model would go faster in both the upline and the downline. Only because the drag is reduced, not the lift. BTW, even in horizontal flight the wings do not produce just induced drag. They are also a source of parasitic drag.

    I respect the amount of work that Bryan has done in many areas. I do disagree with some of his methods and I do believe that though he often ends up at the right place, he really doesn't understand why he ended up there. To many the why is not that important, and that is fine. I think it would be better to try to understand as much of the why as I can.
    TonyF - Team Horizon, Team BJ Craft, Team Contra Drive, Neu Motors
    2010,2009 US Masters Champion,2011 Masters Also-Ran

  10. #160
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    RE: F3A Results - SPOILER

    Remember the story of the tar baby?
    Dejevue all over again
    Libby is still watching you

  11. #161
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    RE: F3A Results - SPOILER

    Low end torque,

    What do we mean by this? it means on a YS(i am referring to the engine brand we use) if you are flying at 1/4 power and need three clicks on the throttle, you can fell the three clicks! you can add a click at a time on a YS with a linear throttle curve and you will feel the airplane gaining authority, not speed, on the other hand, on most electrics with a linear throttle curve you will not feel the power or torque to be there, until you go three times or more stick advance movement.

    The only downside, is only YS users can understand what this feeling is during flight, electric pilots can guess, but only the really top pilots like Chip, Andrew, etc can understand this exactly to the letter compared to electric, because most have flown YS or someone else with enough proficiency, and can simply tell by looking at any given airplane flying.

    I do not counted them but I think there are three guys who claim the lift disappears on a vertical line, including a NASA scientist, and two or three times more people said the opposite, so everyone should be able to get a conclusion, or at least get curious enough to do some research on the matter on its own which is really easy this days on the internet.

  12. #162

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    RE: F3A Results - SPOILER

    Could it be that low end torque refers to the amount of power the motor can produce at the low end of its RPM range? Amount of power would refer to the amount of work (expressed in lbs/ft in the old system) the motor can produce at a given speed (expressed in RPM). Back in the day, a sports car my dad owned had torque curves published in the owners manual. One could determine the best gears to use at different speeds to take advantage of PEAKS in the torque curve. Needless to say, this produced driving satisfaction for dad and reminds me of what some are suggesting on the threads when they compare how different power plant / prop combinations feel under the stick. We would have to see torque curves to compare fairly, no? Anyway, resources are limited so no charts or graphs, but maybe we can solve for the language thing? Cheers!
    Good Flying! Dana
    4449NSRC AMA

  13. #163

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    RE: F3A Results - SPOILER


    ORIGINAL: TonyF

    mjfrederick,

    You use such a crude term as ''urinate'', even when all I have been doing is praising Brett and Bryan for making the team. That is simply untrue and is insulting.
    I used the term urinate, which is the correct term, as opposed to the crude term because I assumed the crude term would be filtered by RCU and I wanted to get my point across. To someone who is just now reading through the entirety of this thread (hadn't read it since I posted on page 1), that's what it looks like you're doing.

    You don't need a Dynamometer to know that an electric motor will always have more low end torque then an IC motor. It is simply the nature of the beast. As soon as an electric motor starts to spin it is making nearly full horsepower. So it will always beat the IC motor in low end power. Just a little more of that science stuff.
    OK, I'll take your word for it. Like I said, don't know anyone with a dyno, and my point specifically stated that Bryan probably wasn't talking about true torque. I'm well aware of the torque capabilities of even the smallest of electric motors at low RPMs. I've seen the damage they can do. Your response is not germaine to the point I was making. But thanks, I guess?

    I have no idea what you could mean from ''horizontal lift''. But wings are not producing any significant amount of lift in either an upline or a downline. They are of course still producing drag. But since they are not producing lift, it is not induced drag, but it is parasitic drag. So if you hypothetically removed them, the model would go faster in both the upline and the downline. Only because the drag is reduced, not the lift. BTW, even in horizontal flight the wings do not produce just induced drag. They are also a source of parasitic drag.
    I can't remember if it was you, or someone else who was agreeing with you, that stated lift is the force that opposes gravity. If the parasitic and induced drag components that pull rearward on the airframe during a downline don't meet that definition in a downline, then neither does the lift produced by the wings in horizontal flight. What I mean by horizontal lift is that the wing will be producing a force component similar to, but not exactly the same as, the force it was producing in horizontal flight. Only this time, the force is parallel to the ground. Hence the pull to the canopy on airframes that have not been trimmed to properly compensate for this. Or the mix that most people end up using.

    I respect the amount of work that Bryan has done in many areas. I do disagree with some of his methods and I do believe that though he often ends up at the right place, he really doesn't understand why he ended up there. To many the why is not that important, and that is fine. I think it would be better to try to understand as much of the why as I can.
    Bryan would rather experiment and get tangible results rather than theorize. I've been fortunate enough to have spent the past 5 years observing his methods up close and learning from him. Most of his methods rely more on common sense than anything else. Although analyzing his methods I can normally explain the why, that's not what's most important to him. I've actually said things before that were just a re-stating of his method from a different perspective, and he thought I had missed the point.

    When I was practicing for the Nats and flying his Shinden (that he had planned on using at the Nats) I was having trouble with spin entry. The plane just kept on wanting to fly. Not missing a beat he said to put an ounce of weight on the firewall. It didn't make much sense to me at first, but I listened. Huge improvement. Only after flying through the spin entry a few times did I fully grasp exactly why the nose weight was needed, and I was able to work backwards to understand the why.
    mjfrederick AMA 275874 NSRCA 4134
    Hebert Competition Designs

  14. #164
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    RE: F3A Results - SPOILER

    ORIGINAL: danamania

    Could it be that low end torque refers to the amount of power the motor can produce at the low end of its RPM range?


    Yes, exactly, and that translate in the ability of turning the prop with enough authority without having to significantly increase the RPM, so you can feel the power increase at lower RPM more than electric, this in turn is easier to control, but the control is a matter of getting used to any given engine/motor, so right there it becomes a matter of preference.


  15. #165
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    RE: F3A Results - SPOILER

    I think we could use this as a fundraising effort for the new team. Get some of those inflatable sumo outfits, sell tickets or online logins for viewing a live wrestling match by some of the most active opinions in F3a.

    We could bid on what gets dumped into the ring at different intervals of the contest.

    I see many dollars to support the US Team in 2013.

    Chuck

    ps. carry on
    Mark Hunt Designs

  16. #166

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    RE: F3A Results - SPOILER


    ORIGINAL: flyncajun

    I think there are too many Brians on this site

    Tony, If thats what offended you I don`t know what I could have wrote differently! and I think it pails in the comparison of insults LOL
    I think for the most part there was some learning here, I was not trying to Cook any Goose,, I was just defending my positions however poorly I did it.

    However I have had more request to trim airplanes this last week than I have had in the last few months, Including one from you Brian some times I think My good nature is being taken advantage of

    Bryan
    Hi Bryan,
    I think you are right about the Brian's.
    You though have the benefit, for ID purposes, of a y.
    Just to clarify, just in case, this thread is the 'goose' I was referring to.
    I was hoping to lighten the mood here a little.


    Brian

  17. #167

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    RE: F3A Results - SPOILER

    On the lighter side of things aerodynamic, and taking up the challenge to do a little searching and reading, this imperfect article illustrates a few of the terms and concepts discussed above (thrust, drag, induced & parasite, etc.). The concept of the power curve may also be useful?

    http://www.aviationschoolsonline.com/faqs/power-curve-article.php

    Pages ago someone introduced the concept of efficiency as critical to performance at altitude which I found insightful. Anything else on that so we can learn from each other?
    Good Flying! Dana
    4449NSRC AMA

  18. #168

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    RE: F3A Results - SPOILER

    According to Lord Kelvin:

    "To measure is to know."

    "If you can not measure it, you can not improve it."

    "In physical science the first essential step in the direction of learning any subject is to find principles of numerical reckoning and practicable methods for measuring some quality connected with it. I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be."

    I believe Tony, Doug, and Dick Hanson, et al, were trying to clarify how things work and should not be criticized for it. They have all contributed a bunch to the state of the art and they should be respected.

    Jim O

  19. #169
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    RE: F3A Results - SPOILER

    Quite frankly -some explanationsI have seen here regarding torque at low rpms- on IC engines -is - simply put- not accurate-

    Electric motors develop full torque from zero rpm.

    You can "theorize "all you like but the usable power on the four stroke is quite a ways up the usable rpm band
    For ones own amazement - setup a model and using a tach and a decent pull guage ( some peizo fishing scales are excellent -up to 50 lbs. - read rpm vs pounds of thrust produced )
    We went thru all this years back - it's all basic stuff -engine 101 if you will.
    Libby is still watching you

  20. #170

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    RE: F3A Results - SPOILER

    Interesting if not espirited discussion....

    Regarding electric motors, based on what I know, the design of the motor is a comprimise between desired torque and speed. In essence, if you want torque at low speeds you sacrifie the high end RPM and vice-versa. The deeply geared set-up favor a motor which generates little torque but which can develop high RMP. It would not be hard to imagine that in a system such as this there would be lag in the response given that the motor has to overcome the inertia of the gear system/prop in addition to the aerodynamic loads acting on the prop. Maybe someone who really understands electric motors could chime in.

    The other thing to keep in mind is that in order for a Theory to be useful, it only needs to be able to predict an outcome realiably, given an input. Whether the theory itself is correct or not does not play into its usefulness. I suspect that there is a little bit of truth in much of what has been said, but I doubt anyone person is 100% regarding the reason why things work the way they do. I just take note of what seems to work and try not to think too much about it...

  21. #171

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    RE: F3A Results - SPOILER


    ORIGINAL: viva_peru

    Interesting if not espirited discussion....

    Regarding electric motors, based on what I know, the design of the motor is a comprimise between desired torque and speed. In essence, if you want torque at low speeds you sacrifie the high end RPM and vice-versa. The deeply geared set-up favor a motor which generates little torque but which can develop high RMP. It would not be hard to imagine that in a system such as this there would be lag in the response given that the motor has to overcome the inertia of the gear system/prop in addition to the aerodynamic loads acting on the prop. Maybe someone who really understands electric motors could chime in.

    The other thing to keep in mind is that in order for a Theory to be useful, it only needs to be able to predict an outcome realiably, given an input. Whether the theory itself is correct or not does not play into its usefulness. I suspect that there is a little bit of truth in much of what has been said, but I doubt anyone person is 100% regarding the reason why things work the way they do. I just take note of what seems to work and try not to think too much about it...
    Think of the gear train as a long lever with a high mechanical advantage (100 to 1). It doesn't take as much force (1 pound) to lift a given weight (100 pounds). And, both ends of the lever start moving at the same time.

  22. #172

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    RE: F3A Results - SPOILER

    ORIGINAL: apereira

    ORIGINAL: danamania

    Could it be that low end torque refers to the amount of power the motor can produce at the low end of its RPM range?


    Yes, exactly, and that translate in the ability of turning the prop with enough authority without having to significantly increase the RPM, so you can feel the power increase at lower RPM more than electric, this in turn is easier to control, but the control is a matter of getting used to any given engine/motor, so right there it becomes a matter of preference.

    Actually this sounds like you could use some adjustment on the throttle curve to get the motor response you're looking for. More often than not the biggest transition when moving from IC to Electric power is the adjustment of throttle curves to get the desired power delivery respective to the throttle stick position, or more accurately, the power delivery that most resembles what they used to have with IC motors. As has been mentioned before by others in this thread, electric motor torque is not a function of RPM like it is with an IC engine. Electric motors are capable of delivering their maximum torque regardless of RPM.
    Doug Cronkhite

  23. #173
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    RE: F3A Results - SPOILER

    ORIGINAL: viva_peru

    Interesting if not espirited discussion....

    Regarding electric motors, based on what I know, the design of the motor is a comprimise between desired torque and speed. In essence, if you want torque at low speeds you sacrifie the high end RPM and vice-versa. The deeply geared set-up favor a motor which generates little torque but which can develop high RMP. It would not be hard to imagine that in a system such as this there would be lag in the response given that the motor has to overcome the inertia of the gear system/prop in addition to the aerodynamic loads acting on the prop. Maybe someone who really understands electric motors could chime in.

    The other thing to keep in mind is that in order for a Theory to be useful, it only needs to be able to predict an outcome realiably, given an input. Whether the theory itself is correct or not does not play into its usefulness. I suspect that there is a little bit of truth in much of what has been said, but I doubt anyone person is 100% regarding the reason why things work the way they do. I just take note of what seems to work and try not to think too much about it...
    Basically - you setup the design of an electric motor such that it is efficient at the speed you want for the prop-
    The key to success is getting this such that the batteries will stay with you for the time frame required .
    Confusing?
    lets take a typical setup- say 11 pounds which has to keep moving and accelerating for 7 minutes
    (a typical FAI model)
    The present motors VAILABLE FOR THE PUBLIC AT LARGE WILL PRETTY WELL USE UP THE STORED ENERGY IN A 10 CELL 5000MA lIpo PACK
    These are simple outrunners ranging from th e EFlite 160- to some pricey stuff- generally speaking - they are about 90% efficient in the power they suck from the batteries.
    The IC engines available can put out more power in this time frame BUT there is a trade off in vibration and absence of available motor braking.
    The electric motor can take advantage of a feature inherant in these motors -they can control prop speed when power is reduced -if you elect to do it .
    The IC engine can not .
    Torque is confusing to many-
    The electric can have the most torque at any rpm -depending on the selected motor design.
    Low speed torque on any of these gas/glowsetups is neither available or required -this is because the props are not really working at low rpms.
    The 4 cycle ICs can accelerate to efficent rpm pretty easily simply because the load is low at low rpm.

    Which setup ispreferrable is what makes for a good horse race
    My choice -is predicated on betting that batteries will keep improving.
    Right now it's nip n tuck on having batteries which will work for the time/load needed .
    Complicate the electricsetup (decrease efficiency) and the batteries have to supply more power -or be larger /heavier -or have greater capacity or C ratings
    If batteries get 20% better at the same weight - then the edge for electric wins going away
    My opinion.
    I do have one of these setups and my son also has one -
    I also have been down he road on trying to get a IC setup I really like - including gassers (too much power impulse problem)
    .
    If you have tried both -you will easily see what the differences are .

    Libby is still watching you

  24. #174

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    RE: F3A Results - SPOILER

    Figure 1 on the link I posted above depicts a drag curve. The curve for total drag is lowest (assume that lift/induced drag and parasite/airframe drag are optimal at this point) at a particular airspeed.  This airspeed might be regarded as "efficient" for the airframe design (so perhaps that airspeed would inform prop choice)? Anyway, a bunch of posts kick around how much drag is designed into the airframe (mono or biplane). What I am wondering now is this low point on the drag curve what the newer designs are driving towards to realize a model that flies "slow" enough to maximize time in box (fit in all the required elements, control downline speed); AND "efficient" enough to make good use of the power plant of choice to fly the schedule in contest conditions (airspeed envelope vs. winds; flight time, etc.)?
    Good Flying! Dana
    4449NSRC AMA

  25. #175

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    RE: F3A Results - SPOILER



    [/quote]
    Which setup ispreferrable is what makes for a good horse race
    My choice -is predicated on betting that batteries will keep improving.
    Right now it's nip n tuck on having batteries which will work for the time/load needed .
    Complicate the electricsetup (decrease efficiency) and the batteries have to supply more power -or be larger /heavier -or have greater capacity or C ratings
    If batteries get 20% better at the same weight - then the edge for electric wins going away
    My opinion.
    [/quote]

    We've been at odds several times, but I agree, with small reservations, with this statement. It is, indeed, nip tuck for the 7 to 8 minutes required. And I do believe we will cross that bridge one day, maybe tomorrow or the next day. Soon. And it made for a good horse race in Muncie last month. Exciting, even. And the electric won. But the IC made it a horse race. Enough so that there are several pilots at the top who are reconsidering their current choices.

    I think the real bear for electrics right now is the power falloff during the flight. IC pulls even better as the flight progresses, due to expended fuel making the plane lighter. There certainly is no power dropoff at the end of the tank, until fuel is expended completely. But MY choice is predicated on what I like; nothing wrong with that, either. There are advantages to either propulsion, but if we see more patterns like the Unknown 1 in Muncie, in similar winds..... advantage IC. I can appreciate the absolute viability of electric flight, however.

    One person that was not given enough credit in Muncie was AC Glenn. Last man up, winds absolutely howling by this time. Several of us judges were certain he would smoke a pack and force landing; but he didn't back off a single bit. I'd like to know the truth about how many pilots did smoke packs that day. AC certainly did, I'm sure Joseph did as well. All of them got the job done, but many of them paid for it later. The IC just had another day at the field.

    Said it before, sayin it again; WOW! those guys really did a great job this year. It was thrilling to see.

    Brian


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