Question on Biplanes...probably the last question in 2 weeks.

[salmendra]

Hi everybody.

I recently downloaded the nice Stearman andthat made me interested in biplanes. So here is the question: In biplanes on which wing you install the control surfaces (and flaps ?) the upper, the lower or both ? Why ?

IŽll be on vacations for two weeks starting saturday. So IŽll probably wonŽt get in the forum much. But until then I will take a look at this thread.

Best

Sergio Almendra
Curitiba - Brazil
(couting the minutes for my vacations of funŽnŽbeachŽnŽcarnival)

[flyinggriffin]

I have seen biplanes with aielrons on the botton and bottom and top. I doubt you would put them on the top wing. It would be tougher to rig and on the bottom wing you are closer to the longitutional axis of the plane

[lnuss]

I've not seen a real biplane with controls on only the top wing but, like Grif, I've seen them on the bottom and on both top and bottom. The four aileron ships generally have the extras in order to get better roll rate, and you usually find that only on ships intended for aerobatics, and far from all of those. Stearmans, for example, were built with one large aileron on each bottom wing, but some have been modified with four ailerons for airshow work. And I've seen Pitts aircraft with both two and four ailerons.

I've never seen flaps on the top wing. Few biplanes even have flaps, but on those that do (Staggerwing, for example) they're on the bottom wing.

Why? All I can say is that's the way they were designed. Of course preflighting an aileron or flap on the bottom wing is easier than one on the top, and there may also be some airflow effects that are more beneficial on the bottom wing (ground effect, interference between the wings, routing of control cables/pushrods?), but you'd have to find an aeronautical engineer conversant with biplane design to get a solid answer.

[HR]
Larry N.

http://www.flightsim.com/dcforum/Use...7454c071bd.jpg

[bilbo]

Not to compound things a bit but the DR-1 had the ailerons only on the top wing. I believe that most of the German WW-I biplanes had the aileorons only on the top wings but not all of them. The Sopwith Camel apparently had four ailerons. The Sopwith Triplane had six. Flaps..what were them thingies?
So, basically I think that it was a mixed bag. Then there was that one venetian blind plane that didn't need ailerons because it fell apart on the takeoff roll :)
Bilbo

[salmendra]

Thanks everybody for the answers. I did noticed the ailerons in the Stearman and the absence of flaps, but didnŽt know if it was his plane or the genarl rule.

Still on the subject, I read somewhere that modern fighters and aerobatic planes still seek the same maneuverability of WWI biplanes. Is that really true ? I can conceive biplanes to have better turning radius because of the slower speeds but I would think modern planes withstand more Gs.

Again thanks for the replies.

Best

Sergio Almendra
Curitiba - Brazul

[flyinggriffin]

Somewhere, I think it might have been the old Chuck Yeager flight simulator said that the top WWI fighter had about the same manuverability and performance of a modern 4 place aircraft.
If you want to see WWI airplanes fly, go to the Old Rhinebeck Aerodrome in New York. You can also fly in the New Standard biplane. One trip in that, when they pull back the power and put it into a slip will show you why they didn't need no stinking flaps. It sinks like stone to the bottom of the pond.

[lnuss]

Even as late a bird as the Stearman had a glide angle of about 45ș. and that was with the speed ring. It was worse without it. There's a fascinating book I picked up a lot of years back, called Flying The Old Planes, by Frank Tallman of Tallmantz Aviation (they did most of the stunt flying for the movies back then).

In that book he wrote about flying both replicas and original birds, from the 1909 Bleriot and Curtiss Pusher to the Nieuport 28, to the B-25 and FG1D Corsair. Those old WW I and before birds were poor in handling, compared to today's aircraft, and many would come apart if you didn't handle them carefully. Being very light and having a lot of wing gave the fighters some maneuverability, but the gyro effects from the old rotary engines meant that left and right turns were wildly different. And a modern day Pitts would run off and hide from those aircraft, not to mention out-handling them. Oh, and those old rotaries coated the pilot (and the aircraft) with castor oil. Also, you had a choice of the engine running at full power or shutting it off -- they had a coupe, or cut-off button, a button in the cockpit that let the pilot intermittently shut the engine off so he could slow down, say for landing.

About the Fokker E III (BTW, it uses wing warping, not ailerons):

The Fokker "Scourge," or Fokker Terror, as it was known in the British wartime press of 1915, is just that as far as this World War II aviator is concerned.
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The immediate reaction when airborne is, "How in Hades did an inexperienced pilot ever fly this bucking bronco?" Climb is at the rate of about 600 feet a minute.
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The tendency as you level out is to want to get both hands on the stick, for, as you pick up speed, it gets very sensitive fore and aft, and you have some difficulty not porpoising.
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Unlike my experience with the SE5, there is no desire on my part to even attempt aerobatics with the Eindecker.

On the other hand he calls the Fokker DRI (Triplane) "...as nimble as a nervous hummingbird"

However:

...and as I began a climbing turn I felt ailerons as stiff as a boiled shirt.
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Putting the red bird in a Lufberry circle, I could see how you could cut the circle small enough to nearly chew off you own tail.

So he had a lot of things, both good and bad, to say about these aircraft.



[HR]
Larry N.

http://www.flightsim.com/dcforum/Use...7454c071bd.jpg

[salmendra]

Well I guess what I read was wrong, at least as a general rule. As I said I had my reservations as well.

Thanks for the comments


Sergio Almendra
Curitiba - Brazil

[bilbo]

I had done some research on that DR-1 when I did a version for FS a few years back and the Rheinbeck plane is pretty authentic however it has a different engine. Something like a continental Radial. As we all know the original was a rotary engine. Some characteristics are different but the main one would be the Hp is about double what the original plane had. I think that they had so mich horses because they used that plane in the "Blue Max" movie. A great movie if you want to see some neat flying action. I saw the Rheinbeck plane take off once and it climbs like a monkey on stearoids. The original plane's power was close to this though. Another issue about the DR-1 was that the pilots were not allowed to go inverted. It may have had something to do with some construction flaws (Notice not design flaws). on a few planes the top wing seperated from the craft while flying. I believe that the plane that the Red Baron's brother was flying lost a wing shortly after it had landed.
What is neat about flying those WW-I stuff in the sim is the necessity to be aware of the weather conditions. If you get socked in while flying, it is very easy to get disoriented and lose that sense of which way is up with the limited gauges that they had. You need to be very aware of the winds on the runway as well as in the air. You would navigate with a compass and a map. I believe that the fields in the days of WW-I were basically square so that if the wind shifted, you landed into what ever direction the wind sock indicated. If you didn't, you'd loose it and ground loop. This would mean at some of todays ports, you might have to land at a right angle to the runway. The DR-1 would be capeable of this. If you get socked in while flying, it is very easy to get disoriented and lose that sense of which way is up with the limited gauges that they had.
Bilbo

[lnuss]

Tallman pointed out in his book that the same horsepower with a modern day engine wouldn't get the same performance in one of those old birds. He attributes this to the difference in the prop. Those old birds had very efficient, slow turning props, around 1300-1400 RPM, and apparently made very efficient use of the horsepower available.

And you're right, Tom, about the flying fields in the old days. They were such that the pilot could always land directly into the wind, rather than being confined to a runway.

[HR]
Larry N.

http://www.flightsim.com/dcforum/Use...7454c071bd.jpg