DominicM

Powered by two PST130 micro turbine engines this 1/6th scale Fokker 70 Airliner gets in the air rapidly and cruises around the sky until it lands and comes to a stop thanks to it's new thrust reversal system.

erbroens

Fantastic...thanks for sharing

jcterrettaz

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gorgeous plane , great pilot, thanks you

Ragz

one of the best RC airline flight video i have seen. Amazing engineering.

Zeeb

My Feedback: (41)

Sorry I do not agree. While the landing actually turned out very nice, everything else about the flight had a lot to be dissected.

I always amazes me that guys who've been around RC long enough to develop the skills necessary to build something like this persist in the idea that they can fly the thing. If you look at any scale competitions, builders almost ALWAYS have pilots to fly them. In this case, there was not one turn that was coordinated. Don't these guys ever use rudder? The take off was not good, chased the runway centerline until it wandered off to the side of the runway and he had to jerk it off to avoid running off the runway.

However; the thrust reversers were WAY COOL!!!!

highhorse

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ygtbkm.

grbaker

My Feedback: (29)

Very nice Dominic!!!

RCFlyerDan

My Feedback: (54)

Zeeb, you are the most perfect RC pilot ever! At least in the arm chair. You always have something negative to say. IF you were a full scale ATP jet Capt, you would know that rudder is NOT used during turns. There isn’t any P-Factor for the need, or the prop wash corkscrewing around the fuselage. If you are a full scale jet captain and used rudder during turns, I wouldn’t want to be riding in the back from the side loads that you were creating. Rudder is only for engine loss, and runway alignment during Xwind. Pilots coming from Prop job had to be knocked in the head to get off of the rudder in a jet. You would also know that nose hunting is a characteristic of a swept wing jet! And, if you were a better arm chair pilot, you would also see that what looks like an uncoordinated turn, is the nose high attitude from slow flight, and the crab angles going through the turn to make it look like the jet was sliding.


Rotation is pretty darn close to center line. He started his take off roll at an angle due to the crosswind.


Pretty smooth rotation


Not lined up with centerline due to Xwind.

IMHO…he did over control from too sensitive of an elevator. But! Hey! We don’t know if this is the second flight or still under 10 flights and still adjusting balance, trims, and throws.


Pretty strong, gusty winds. The other consideration is that maybe this guy is the best jet pilot on the home field. There are a lot of guys who fly jets, but it doesn’t mean that they should be. Nor fly someone else’s jet.

highhorse

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To clarify, rudder is used quite a bit in jets regardless of their lack of prop-related issues, BUT is typically handled/manipulated automatically by yaw dampers which do a great job of, among other tasks, keeping turns coordinated.

The model in question may or may not have a yaw gyro for essentially the same function. Probably does, and if so may not be totally dialed in. REGARDLESS, where the unproductively harsh critic a few posts above sees only supposedly grievous piloting errors and uncoordinated turns -all of which of course demand his derision- I see an incredibly nice jet, well flown in a crosswind which has the effect of making even perfect turns look a bit odd.

Personally speaking, I believe that derisive keyboard-warrior posts of that sort have no place in our hobby…serving only an author’s ego at the expense of others’ enjoyment. It’s just a &%^##@ hobby. Supposed to be fun.

baron-noir

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Not sure the yaw damper would dial in rudder for coordinated turn in a conventional jet, source pls ? To my understanding it was designed to cope with dutch roll issues of early jets at high altitude where it could lead to loss of control and was quite nasty.

Zeeb

My Feedback: (41)

Early LearJets had issues with Dutch roll due to the weight and sloshing fuel in the tip tanks. One of the planes I have some time in was a Lear 25D which was the fastest of all the Lears when produced. It has two yaw dampers and they are both on the pre-takeoff checklist. If either one fails the TO pre check, it's a no go item.

Even with that, we had one new pilot type trying to get qualified in the 25D and he got a Dutch roll going on so bad on a landing attempt, that he scraped the tailcones of both tip tanks on landing. Cost the company $12,000 to repair those two tip tanks but we were lucky, the conehead could have wound up in a ball of fire on the runway.....

highhorse

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Yaw damps do indeed serve the function you mention…they do so via countering adverse yaw which at high altitudes and/or speeds with swept wings (i.e. jets) can, as you’ve noted, be quite an issue.

Note please though that Dutch Roll (adverse yaw) as you’re referring to in the above circumstances is simply an extreme example of the common adverse yaw exhibited in uncoordinated turns. Conversely, benign versions of Dutch Roll are easily demonstrated in slow, straight-winged trainers with repeated stop-to-stop manipulation of the ailerons while rudder is held neutral.

On a basic level then, Dutch Roll = lack of coordination and lack of coordination = Dutch Roll. It’s really not more complicated than that.

So yes, yaw damps (especially more modern ones driven by better and more sensitive accelerometers and algorithms) therefore typically coordinate turns just fine, negating the need for direct pilot input to the rudder(s). If you want sources then I refer you please to whatever on-line manuals you can find, as I am too lazy to copy and paste here from the manuals for the jets (heavy and otherwise) in which I have made my living for the last 37-ish years. There’s really no magic therein though that isn’t found in a good RC gyro. Same thing, different scale.

Seems odd now, but back when I was engaged in regular recreational aerobatics during days off, I had to consciously re-train my feet during the first leg back at work to leave the jet alone and let the damps do their thing lest I slosh the ass-end around :-)

BACK TO THE TOPIC AT HAND THOUGH :-) the Fokker in the OP is way cool, flown well, and assertions otherwise are bunk IMO because this is a hobby, the jets here are toys, toys and the sharing of them is supposed to be fun, and the judgmental, arm-chair, keyboard-warrior vitriol exhibited in one of the posts above has no place in the hobby or these forums.

Rather than self-promoting derision, let’s just get back to the sharing and mutual encouragement that benefits our wonderful hobby, shall we?

Peace Out.

Zeeb

My Feedback: (41)

Do not assume as fact that something you do not understand, or find challenging, is of no use to the pilot nor other observers;

Control coordination does not count; when was the last time you judged an IMAC competition.

Smooth coordinated flight with no skids or slips; have you ever had to judge an F3A competition?????

Just two of the examples I can think of which make your assumptions and high horse attitude worthless to this discussion. Go back and play in you own sandbox again and leave us alone......

highhorse

My Feedback: (2)

Never have I judged model competitions, but I have competed (and won) full-scale acro competitions. I was also a certified judge for same. If generous, one might assume that I know a thing or two about coordinated and other modes of flight, NONE OF WHICH ARE THE TOPIC OF THIS THREAD and only mentioned herein because you couldn’t refrain from going completely off-topic in and attempt to make yourself feel better at others’ expense. But gee, since I haven’t judged or flown competitions on a smaller scale with our fellow hobbyists and our toys I suppose you have 100% exposed me as the unwashed and unworthy pretender that I am.

Pretender or not, I will point out once again that this thread was not intended as a venue for your unsolicited opinions regarding fellow pilots’ skill or knowledge sets. This thread which you’ve crapped all over is about an amazing effort by our fellow hobbyists (HOBBYISTS!) at reproducing a terrific scale feature. An effort worthy only of praise.

The best pilots I’ve known in either full-scale or RC endeavors also exhibit an unfailing grace and humility without the need or desire to publicly deride others’ efforts, let alone to repeatedly go out of their way (and off topic) to do so.

So I will try one last time…Please try to remember sir that this is a hobby, it’s supposed to be fun, and the members within this slowly shrinking world are your fellow fun-loving hobbyists rather than mere fodder for your chest-beating diatribes. Would it kill you to just be…nice? Yes, I imagine that it would and that you’ll be back with a fresh round of derisive insults aimed at your lessers. Knock yourself out then and insult with impunity, as I am 100% done here.

baron-noir

My Feedback: (1)

Well I offer that this discussion about yaw damper has a direct link to R/C. Specifically if one is to maintain that it keeps turns coordinated (by applying rudder) as there is a well know mix available since the first age of "electronic T/X" which couple the rudder and aileron which offer to do the same. I never used that kind of mix cause I don't find it "natural" and is a big no-no for sailplanes for instance. I was not aware that in real airplanes you had yaw dampers doing that turn coordination also, for the reason that it seems counterproductive in landing with crosswind for instance. So I guess that whatever the yaw damper is doing in keeping turn coordinated, it is doing it only for small amount of rudder input and can be overriden by pilot input. Systems and equipment aboard aircrafts and how they function are normaly described in manufacturer manual (FOM etc.) so that is the reason I was asking for a source. If you don't want to provide that's fine, this is just a hobby forum. No need to go balistic either.

David Gladwin

If you really want to lean the REAL truth about Dutch roll, yaw control , turn coordination, ( as on the 747) yaw damper gain change, rudder ratio units, interaction between spiral and lateral stability, fin size, etc., and recovery techniques then you can do no better than get a copy of “ Handling the Big Jets” by D P Davies. DPD evaluated, for certification , all the jets from the Comet to Concorde and his book is an absolute bible. When I joined BOAC on the VC 10 fleet( an aircraft that could develop serious Dutch roll due large wing sweep and had three rudders and three yaw dampers to prevent it) in 1974 this was the very first document the airline gave us. A highly respected work, fully valid today.

Anyway, for a model jet just put a gyro on the rudder, set gain just below oscillation level, and you will be fine. (PoweBox I gyro SAT is a superb and extremely competent device)

Personally, I thought the Fokker was VERY well flown. Rotation, ground spoiler lift and reverser bucket deployment all spot on!

JamesKNMA

All around impressive aircraft and flying! Also appreciate the camera person's use of a real camera and ability to keep it in frame.