The Thundergazer is OK as is.  As I recall, it won its first contest (Landres, 2008) and has won some contests in Muncie since then.  

I've been told that the best situation is to have the thrust line, wing and stab all on the same line. Since I'm going electric with my Thunder Gazer build I'm thinking of scrapping the fuselage and making it this way. Just wondering if this really makes any difference. What do you think?

I have not done any extensive research on this, but---

Except for Bob Baron and his Avanti II in '96, I cannot recall any other design that has won the Nats or has even been in the top 10 for say, the last 40 years or more, that was set up with everything on the same line.  There probably is a reason for that.

I am less sure, but much the same thing can be said about the World Championships.

It would be an interesting excursion to build one and tell us how well it works.

Keith

I don't know why the currently-popular arrangement of prop-wing-tail works, but it certainly seems to be the way to go.  Personally, I would hesitate to change it.

If you're going to change absolutely everything anyway, why don't you leave the Thundergazer kit on the shelf, or sell it, get a wing kit, and go build what you think is right?

How do you explain the Sharks  aren't they all inline???

Have they won any national or international contests lately?

Somehow I think that if an all-inline plane had a strong advantage you'd see all-inline planes at contests, just from sheer evolution.  I'm of the "if I don't understand it then I'll copy someone who wins" school of design detail, and it sure seem that the field is heavy with non-inline planes to go and copy.

...isn't there a shark on the US World team and also in contention at the NATS...?

Yes there is. I saw one last week and another today.  They are electric, too. 

YES I agree ... inliners are much better ... then wrong designed non inliners ... for example those with opposite prop :- ))))))))))))))))))

BTW if you want realy symmetrical inliner, you must have also LG on top of fuselage 

Good one Igor! 

I saw one like that back in the '50's..........Might have won a landing contest 

Jerry

To summarize the responses - no, "in-line" is not necessarily better, or even as good. It certainly doesn't create any sort of perfect symmetry unless many other things change.  I would be curious about where you heard that, but I doubt it was from current competitive stunt fliers. As Keith noted, Bob Baron's "AVANTI" was the only successful one designed in the US in recent history, and he later claimed the Patternmaster was a big improvement.

    And if you want to build a Thundergazer, stick to the original design until you have flown it enough to discover any design defects, and are able to distinguish the design defects from tiny differences in the trim, power, and construction you may have built into it. And while there is no guarantee that the design itself is perfect, the fact that it has won 5 or so NATs, a WC, and numerous other high placings in the biggest contests suggests it has no fatal design flaws. I saw it get *603* points in 20 mph winds *yesterday afternoon* as it is.

   David will not respond here because he doesn't do Stunthangar, but having been his close flying buddy the entire time the Thundergazer has existed, and having flown what was maybe the 4-5th flight ever on the first one, I expect that he would say "build it however, but if you make any big changes, you are on your own".

    I would recommend building it as it comes. If it is a little beyond your current skill level, then it will serve as a learning experience, but if it is way beyond your current skill level then I would suggest putting it aside and working up to it. It's not particularly hard to build by top-end stunt standards, but it's pretty complex by CL general standards, and one mistake could doom the entire project. Only you can judge for yourself.

     Brett

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As Keith noted, Bob Baron's "AVANTI" was the only successful one designed in the US in recent history, and he later claimed the Patternmaster was a big improvement.

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     Brett

In fact, I stand corrected.  Thank you Brett.  Yes, Baron did the two Avanti designs, the second with in line engine/wing/tail.  But I think he won the Nats with a Pattern Master or at least his version of a Pattern Master.  I remember him commenting when he was awarded the Walker Cup that day that he won with essentially "retro" equipment with the ST 60 (no pipe) and the Pattern Master which had been designed years earlier when ST .60's were "the force".  (And the Pattern Master is not an in line design.)

Hey Brett, congratulations on your win in Madera.  That is impressive.

Keith

In fact, I stand corrected.  Thank you Brett.  Yes, Baron did the two Avanti designs, the second with in line engine/wing/tail.  But I think he won the Nats with a Pattern Master or at least his version of a Pattern Master.  I remember him commenting when he was awarded the Walker Cup that day that he won with essentially "retro" equipment with the ST 60 (no pipe) and the Pattern Master which had been designed years earlier when ST .60's were "the force".  (And the Pattern Master is not an in line design.)

     I am not sure what I corrected you on, but the in-liner was the problem child. If a Patternmaster is a big improvement, that tells you what Motorman needs to know, because it's not particularly good, either compared to the usual Impact, Trivial Pursuits, etc.

Hey Brett, congratulations on your win in Madera.  That is impressive.

   Some things lined up to my favor, and I found some inspiration shortly before my second flight, but, yes, I was pretty happy with the outcome.  I did put forth more-than-average level of preparation,  at least by my standards of recent years. The scenario was just about the same thing that happened in 2013, but with David and my roles reversed, almost down to the details.

    At any rate, even being competitive in such a contest, much less winning, is a pretty big honor. I look at the trophy plate and it looks like a who's who in Stunt. I'm on there 4 times, but almost lost among the Ted Fancher, David Fitzgerald, and Paul Walker engravings.

      Brett

John refers to Yatsenko Sharks, which have.

I was stuck on Jetco Sharks, possibly because my flying buddy has two.  D'oh.

I will reiterate my earlier comment however: if 0-0-0 setups were overwhelmingly better, or overwhelmingly worse, they would either be consistently winning or consistently losing.  If there is an advantage it is slight, and it's very likely one of those compromises where you gain something in one area and lose it in another.

   It probably makes a difference, and it probably shouldn't be in line, at least until you come up with a zero-angular-momentum motor/prop.

     Brett

Twin engine counter rotating props anyone?

  Single-engine counter-rotating props, maybe? Randy had an effective "angular momentum canceling" system nearly 40 years ago!

It's been done on RC pattern planes with electric motors.  I'm pretty sure that I've seen systems commercially available for teeny little 3D foamies and for great big "120" sized pattern ships, but there may be something in between.  So it may even be something one could do with off the shelf parts.

The setup will cost you bux or time: the systems that I've seen use special motors with hollow shafts and all the associated hardware for the rear prop is special.  I'm pretty sure there's also an issue of getting the pitch of the rear propeller correct -- I seem to remember reading somewhere that if you just pitch it to match the front one that it more or less goes along for the ride rather than doing useful work on the airstream.  So you either need to find one and pay bux, or you need to machine your own parts to power the rear prop, and try to keep the whole assembly stout enough for stunt.

Or you could do a dual-nose setup ala Harold Wagner (this was done at an airport about 15 miles from where I grew up -- and I never found out about it until after the place had been decommissioned.  Oh well).  This write-up is from Fiddler's Green, but there's pictures of the real thing http://www.fiddlersgreen.net/models/Aircraft/Piper-TwinCub.html.

I posted those pictures already few times. Whole polish team flew this year ECh with contraprops.

only prototypes so far

... and how? well noisy :-P

check results yourself :- ))

I think Jim Casale's Columbia and Discovery were in line thrust. He had Nats success with them.

Over the years I have heard that centerline thrust causes hunting, but it could have been do to bad alignment.

Yep. The Columbia jet was all in-line, as was pretty much everything he built/flew after 1988.

He must be a really good machinest.  Look carefully at the head and you see two glow plugs.  It is clearly a split-piston engine, with each half piston driving separate connecting rods to turn the two shafts. 

Wow.  I see what you mean.  I wonder if the pistons are ringed?

FAI Free Flight guys have been using geared contra-prop IC engines for years. The parts stand up to 30,000 rpm runs, so would probably last on a stunter. I imagine the parts would have to be beefier for our much heavier models but the concept is proven.

Mike,

That is not so. Geared engines (about 1:4 planetary) are popular but nobody has contra-rotating so far.
Actually, with the folder models, people are going back to direct drive.

Lauri

Looks like R/C pattern fliers use big props at low RPM with contraprops: http://amablog.modelaircraft.org/fai/files/2014/02/CIAM-Flyer-1-2014-email.pdf

   No offense to the owners, and maybe that's whats required, but those are some *ugly* airplanes!
 
    Brett

   

YES modern pattern aircraft are no where near as attractive as pattern ships of the 80's

Can't be much in it Laurie, although the Ellipse shows some deviation as you have noted.

I just measured 5 models, from the earliest (square stab & rudder) to the first & last ellipse versions.
They all have thrust line 7...8mm above wing centerline. L