UStik

OK, fuse and wing sketches are corrected, amended, and modified ( and now the stab added). The bigger ones are turned to prevent the forum software shrinking them.

Please notice the main landing gear is now correctly placed. The strut is perpendicular to the wing's lower surface, so slanted backwards and sidewards. I used 4 degrees dihedral to derive position and length because Ed had settled on that value.

The top block (turtledeck) is now 1", as Duane wished, so the fuselage's upper outline is horizontal from canopy to rudder. Don't know if that's correct but seems consistent (why not).

The rudder rake was simply set to 45 degrees by setting the fin/rudder tip more forward. The distance between rudder hinge line root and tip is now 11.5" both vertically and horizontally. Looks quite consistent as well.

By the way, I used no CAD but a quite simple drawing program (Inkscape, giving SVG format).


The C/G is not that far back, it is just 5% of mean chord ahead of the neutral point. As Andy said, that is quite far aft due to the wing sweep. But also the stab on its moment arm contributes to the position of the neutral point (red in the plan view), which is 4.35" ahead of the aileron hinge line. That's all determined by the airplane's geometry.

The C/G at 5% static margin is more or less set arbitrarily. 5% is a value common for "neutral" aerobatic planes while more stability is achieved with 10% to even 15%. Maybe that would give a C/G position more familiar to you, according to the usual 25% to 35% from leading edge rule-of-thumb.

kingaltair

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Impressive....quite impressive . That little drawing program of yours really WORKS.

When you look at the top view, the tail moment doesn't appear to be particularly long does it, (compared to the Taurus-2 (remember the Taurus-2), or even the Taurus. I'm a little surprised; too bad because it would probably fly better with the tail moment a little longer. Just an educated guess judging with our experience with the King Altair, the other big plane designed at the same time by Ed's friend Vic Husak. The King has a much longer tail moment

I think the plan is going to show 2 degrees dihedral per panel, (instead of 4 as Ed settled on). I believe it looks better, and time has shown over the past 45+ years that less dihedral should fly better. There have even been some within the "team" that advocated for a flat wing like the modern planes; but we felt it needed some dihedral to be true to Ed's design. At least the 2* dihedral is something that Ed actually tried, (though he didn't settle on that figure).

Burkhard, double checking and confirming measurements and calculations is simply the sign of a good team effort...nothing personal, and your figures were confirmed.

Thanks again.

Duane

UStik

The tail moment arm isn't that short if you compare it to the mean wing chord: 37/13 = 2.85, the moment arm measured between mean aerodynamic chords. A slender wing (aspect ratio 8) needs not as much moment arm as a stubby wing. And it's nearly the same value as on the 1" longer Contest Taurus. But could be (and King Altair is) longer ...

And I had forgotten to plot the overall length dimensions, after the vertical tail modification. Look at the length including spinner, isn't that a nice round number?

jjpetro

I'm going to include a solid and built up aileron option in the kit. I like the solid because you can taper it near the wing tip and not worry about getting into the hollow space of the built up aileron. I like the built up aileron because it provides a cleaner transition from wing te to aileron le. The drawings will reflect both methods.

The cost for both is a couple extra pieces of balsa sheets and two square strips.

The drawing shows the two options from my post yesterday plus Evan's and Andy's ideas. Andy's idea is fairly ingenious. Just bevel a square strip and glue it into the wing and then cut it in half later. Somewhat similar to what we did on the King except he's taking care of the te and le spar before sheeting the wing (jump in and elaborate Andy!).

We've spent 3 days on the aileron (well, at least I have). It's time to get back to the design and drawing!!!

AndyKunz

Actually, Jeff, you glue a square strip in and bevel it after cutting it out. It would be kind of hard to put the bevel in before, I think. From a kitting perspective it would be pretty tight tolerance to keep your saw cutting properly.

The other thing I do is arrange the rib building tabs so the span the aileron LE area, but with pre-cut areas so they snap off better. I'll be sending you an update on the e-mail from yesterday so you can see what I mean. The nicest part is that all the ribs are computer generated so there's nothing to worry about with misalignment. Even the wing joiner tube is located automatically (and perfectly!).

I wrote it up in pretty clear text for the Flying Models article. When it gets published I'll give you "chapter and verse" to look in your copy of FM. You all do get Flying Models, right? The only American magazine that really takes care of "real builders" today...

Andy

kingaltair

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I used to, then I switched to "R/C Report"...just before it went "belly up". Guess I need to subscribe again.

Duane

UStik

Now fuse, wing, and stab sketches are corrected, amended, and modified again. The bigger ones are turned to prevent the forum software shrinking them.

I'm still wondering why (Ed and others) liked big dihedral. In the fuse sketch, the wing is drawn for 4 degrees of dihedral, the value Ed settled on. It turns out that the center of lift, which is the center of (wing) drag (drawn red) at the same time, is nearly exactly on the center (thrust) line. Since the wing makes for more than half of the overall drag of the model and moreover changes with AOA, that should give a consistent pattern flying without changes of moments. Just an observation ...

The wing sketch now shows all in correct size, including landing gear and plug-in tubes.

The stab seems to show the same trick Ed used on the wing: The tapered outline with a constant-chord elevator gives constant height of the elevator spar - nearly. I tried NACA 0012, 0015, and 0018, but in all cases the tip is 1mm thinner than the root. Now I just assumed 15% thickness, giving 1.5" absolute thickness where the stab meets the fuse. An even thicker airfoil would make the "1mm relative error" on the elevator stab smaller, but the photos show parts of the round, 2" thick turtledeck on top of the stab, so 15% seems reasonable.

In the pictures, the rudder seems to be flat, maybe slab balsa.

Ideas, suggestions?


By the way, Ed still designed kind of a "reeds model". The elevator has 20% of the area of the whole stab, the rudder 25% of the vertical tail. In the simulator, both controls need 45 degrees throw to get the plane barely spinning.

As to the landing gear: The main LG was perpendicular to the wing's lower surface and slanted outwards with the dihedral angle, clearly visible on the pictures. Different dihedral means different landing gear height as well, so Ed must have had the nose landing gear adjustable in length. According to the W/E ad, Simla had "a special nose wheel for a nose high take-off". There's nothing like Cees' mechanism on Simla, so I assume Ed did it with the strut moving vertically in the Nylon bearing blocks. Maybe there was a ratchet holding the strut down for take-off and retracting when the strut fell down a bit in the air. On touchdown, the strut could go upwards to give a level or nose-down attitude. Remember Simla had the engine bay open on the right side so the landing gear was easily accessible. Too bad the picture in the "Big Stuff" article is so small.

pimmnz

Nice, UStik, it's beginning to look like a smooth job. Definitely need some sort of plan, it would be too cool to turn up with the PCM and Simla, but then I just might...
Evan.

RFJ

A little light relief from all this design theory - Ed obviously wasn't the only one trying the "big stuff" concept.

Ray

pimmnz

Lord, don't let Duane see it...King king Altair...he's gonna want one of them, too. Not enough balsa for all these things...think of the rain forests...
Evan.

jjpetro

Duane!!!!! Another project!!!!!

Michaelj2k

Wow, it looks like there's going to be a Simla in every shop! Now if only there was enough information available on Brett's TBX-1 for a reproduction. I was at the 1965 Willow Grove Nats when Ed flew the Simla but of all the pattern planes I saw, I can only recall the TBX-1 and Marty Meyer's Skyliner Class II ship. Wish I had a camera.[&o]

jjpetro

Michael,
Do you remember where the Simla placed in the 1965 Willow Grove Nats? Duane and I were trying to figure out exactly which events the Simla won.

kingaltair

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Now that's interesting isn't it. Ray, why do you keep doing these things to us...just when we're starting to think we have things figured out.

Earlier in the thread, (and I'm NOT going to look for it), results of the, (I think 1965 NATS) plus a chart of what all the pilots flew, prop used, radio etc were published. I looked at all the pilots and their "vital stats" and saw that Vic Husak was flying a plane called the "Cream Puff". There was even a picture of him and the plane. It was a little disturbing to me since I had corresponded with Vic for over a year regarding the King Altair, and he never...not once...mentioned NOTHIN' about NO CREAM PUFF. I wanted to think I knew something about the times and the planes the people I knew were flying, but here was this big, (literally) surprise. Vic told me the King Altair was designed around 1965 at about the same time as Ed's Simla...in fact I thought the King Altair WAS Vic's version of a large pattern plane.....but nope. These classic pattern pioneers were just full of surprises back then weren't they?

I know, (according to Cees), we are not supposed to speculate, "...just the facts...", but in this case we have no choice. My guess is that that King Altair came after this Cream Puff, and was a supposedly more realistic alternative to the 8ft wingspan "mega-planes" the "Chicago Boys" were producing at the time. It has the King Altair tail.

On the other hand, the Cream Puff has the rounded wingtips of his 1972 design the Mr Slick, (also featured in RCM with plans), so who really knows? Wing looks pretty thin. Powered only by a ST .56, that thing must have been a "motorglider".

Duane

kingaltair

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I wish you had a camera too. Looks like that was a good NATS to go to, a lot of interesting planes that year. I saw the TBX fly at our home field. I know it had some kind of pressurized fuel system because Tom was having trouble with it. At the time I wasn't a very diescriminating pattern pilot, (actually I wasn't a pilot at all then), so I couldn't evaluate how well it flew; I just remember it being up there in the sky watching it, and being impressed with those dramatically swept wings. It probably didn't fly worth a darn (at least as far as doing precision aerobatics is concerned, especially on reeds which Tom flew), but it sure looked cool. I think Tom's wife still has the plane along with the Apogee, (sister ship of the Perigee), and a Perigee kit.

Hey.....at least we have a SIDE VIEW of this plane

UStik

Another one by Ray! "A little light relief from all this design theory", is that British understatement or plain irony?

Duane, don't even think of the TBX-1! It has anhedral, drooped wingtips, and such things that show that Tom Brett had thought (and tried) much about stability. I'm not sure if we're able to hold a candle to him.

The Cream Puff (still in doubt what that is in German, a hollow pastry with cream in it or just a dollop of cream?) could be figured out, though. It is a motorglider like Simla with its slender wing and maybe even thinner airfoil (which requires more building effort than a thick one). But it's a real mid-winger without dihedral but longer tail moment arm. (And does it really have retracts?) I repeat my speculation that the really big Simla maybe was an experiment typical for Ed, making it as big as possible so he would see where the right compromise between Taurus and Simla might be. Ed ceased model flying, Vic Husak continued with the King Altair - possible?

kingaltair

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I think you may have hit on something with that statement, (although I don't remember you making it earlier). Ed had to make the Simla big enough, (significantly larger than the 60-size pattern ships), to more clearly be able to see the difference that size makes in the flying characteristics. Unfortunately, he didn't have larger engines available to really give the larger planes an even chance.

BTW.......I dropped by my friendly Volkswagen and Porsch dealership yesterday to look around. More German engineering on display.

I half expected to find "measurements" all over the cars.

Duane

UStik

Looong ago, post [link=http://www.rcuniverse.com/forum/fb.asp?m=8710881]#1345[/link] on page 54.

Don't expect measurements on German cars, they don't disclose their secrets. What I'm doing here is German reverse-engineering.

How about Cream Puff? If it's a hollow pastry with cream in it that would be apt - German "Windbeutel", English "puff" but literally "wind bag".

kingaltair

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Well I guess you did after all...it must have been lost in all the comments about "meeger times...bad weather...climate change...and the Veco .61..." A .61 is still a .61....it might have made some difference, but give me an O.S. .60 that I can switch out with a .90, (same mounting holes and dimensions) anyday.

Cream puff is a light, hollow pastry with cream inside. It's also used to describe something or someone that is not strong, or who will not put up any resistance in a fight. Let's hope our Simla is not a "Cream Puff" I know it's a "catchy name", but why would somebody want to namke their plane a "Cream Puff"? People would then be saying, "...I got beaten out for first place by Husak and his Cream Puff"...it just doesn't quite fit the image of a championship plane.

Duane

RFJ

Michaelj2k - Marty Meyer's Sky-Liner, a classic Class I/II design. Bet it flew well.

Duane - Vic also had an 80" version of the Cream Puff (called, naturally, Li'l Cream Puff) which he flew at the 1966 Nats. He placed 52nd out of 126 Class III entries.

Ray

UStik

The first one was answered before as well - you could switch engines by switching them including a (soft) mount. Should be enough room, at least if you use mounts with integrated nose landing gear bearing blocks. If the hole patterns are different use clamps as Ed did on the T2 mounting the ST58.

Cream Puff could be play with ambiguity. In German, Windbeutel is even someone who is charming but not reliable, for instance not qualified as a son-in-law. But in this case Vic Husak could have said a competitor was beaten out even by a cream puff, "someone that is not strong, or who will not put up any resistance in a fight". On the other hand, Cream Puff characterizes the model quite well. It's big and light, sweet and elegant.

Maybe Vic Husak had even slightly better models than Ed, but Ed was a better pilot (the 35%/65% thing)? I think they just had slightly different preferences (Ed liked more dihedral, Vic longer tail moment) according to a slightly different flying style. After all, each top pilot designed his models to his flying style (and special strengths and weaknesses) or he would not have been a top pilot.

jjpetro

Another surprise for you Duane?

Well, Vic came out with the King in '67. The Cream Puff fin/rudder looks a lot like the King fin/rudder. Which came first the Altair series or the Creamy Puffy series?

kingaltair

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Ray...I forgot to mention that Donald Wehrheim, who reads this thread and used to fly with Ed, Vic, and the "Chicago guys", sent me a few pictures of a local event they held. Some of the pictures were dated "1965", of course during the warm weather. The picture shows Vic flying what obviously is a King Altair. This tells me Vic had BOTH at roughly the same time, with the original Cream Puff already done by Feb 1965, for the Toldeo show, (where new products and planes are displayed). The concept of more than one project going on at the same time...does that sound familiar? In fact, I'll bet you the picture of Ed's "pusher" was taken at Toledo about the same time.

Looks like the King Altair and the Cream Puff/Little Cream Puff, (because the BIG Cream Puff probably flew like a "hollow pastry with cream in the inside") , were right on the heels of each other. Maybe the King Altair was a little before the Cream Puff, but I remember however that Vic said it was designed around 1965. Who knows?

Ray, look what you've done !!

AndyKunz

A Cream Puff is also something that is "the best in its category" just like the pastry cream puff is the best thing on the planet. My grandfather had a bakery ("Old Homestead Bakery" in Washington, NJ - now it's part of a gymnasium) when I was growing up, making all sorts of wonderful Old World German pastries, breads, etc. Nobody could make cream puffs like his! All the food that didn't sell came to our house, and what we kids didn't eat, we fed to the chickens. Second best was schweintorte ("Pigs Ears" ).

Andy

kingaltair

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So this term "Cream Puff" means a lot of things to a lot of people, and the exact meaning probably depends on if the person has a smile on his face when he says it.

That's right...Ich habt vergessen. "Cream Puff" might be a REAL NICE old car for example.

Duane