Previous Thread
Next Thread
Print Thread
Rate This Thread
Hop To
Page 2 of 2 1 2
#2786359 - 12/01/06 09:46 PM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Feb 2005
Posts: 46
k5054 Offline
Junior Member
k5054  Offline
Junior Member

Joined: Feb 2005
Posts: 46
Oxford, England
That's not reversing, thats 360deg. An 8 seconds turn is 45deg/sec. It's an extremely fast rate by any modern standard. At 90mph it's 3.24g. That means for a DVII a lateral force of 6480 pounds generated by nothing but the flat-sided fuselage and a few tubular struts, plus any component of engine thrust. Not possible. If your fuselage can do that, what do you need wings for.

In a proper banked turn, a 4 second circle was certainly possible with some WW1 aircraft. And they could take the g, too.

Inline advert (2nd and 3rd post)

#2786360 - 12/02/06 12:47 AM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Feb 2001
Posts: 1,657
Neal Offline
Member
Neal  Offline
Member

Joined: Feb 2001
Posts: 1,657
Info I'd seen years ago pointed to those planes having much less than 6 G structural limits. Please, where can I see different?

For sure they could not turn any 3 G's and maintain alt, they did not have the power! You wanted to pull much angle, you had to trade either speed or alt.

When they are going real slow they can turn very quick although the Camel especially was able to swing around on its nose in a torque turn incredibly fast, that was not a circular path or constant speed maneuver.

Slip-roll coupling. You yaw an airplane and one wing (the one swung forward) has more lift than the other, the plane will automatically bank into the turn.

So simply I would like to know if those guys are talking wings-flat turns (what he mean by no bank as I wrote above) and if so how he maintained wings flat when the plane will naturally bank itself. Again, when he says no banking did he mean that he did not use banking to start the turn or did the wings stay flat --
one does not automatically follow the other but hey there might be some trick used that consider a sim 'adjusted' to fit the interpretation of the description without using the trick and what kind of FM might result.

#2786361 - 12/02/06 04:30 AM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Nov 2006
Posts: 12
Blue Dog Offline
Junior Member
Blue Dog  Offline
Junior Member

Joined: Nov 2006
Posts: 12
Daytona Beach, Florida
Right now, I'm talking about a zero bank, rudder turn. Whereby the pilot utilizes only rudder to turn the aircraft. Yes, Neal, you are correct in your statement that when rudder is applied and one wing moves faster through the air (forward of the other wing) it generates more lift. So a left rudder turn would require right aileron in order maintain wings level throughout the turn. like I said before, such maneouvers are for training purposes only! If you get too slow and don't ride the buffet just right, your going to find yourself in a spin real fast.


No avionics? No problem!
#2786362 - 12/02/06 09:42 AM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Feb 2005
Posts: 46
k5054 Offline
Junior Member
k5054  Offline
Junior Member

Joined: Feb 2005
Posts: 46
Oxford, England
Info I'd seen years ago pointed to those planes having much less than 6 G structural limits. Please, where can I see different?

That's a difficult one. 6g would be about right, maybe a little more but testing was primitive or non-existent. You probably have seen pictures of sandbag tests, or factory personnel sitting along the wing. That's the kind of thing they did, and it's a static test, and goes nowhere near flight conditions, with thing being twisted and pulled in different ways, not to mention flutter and other aerodynamic effects. Bottom line is that these aircraft were pretty tough, not the fragile crates that some people envisage.

#2786363 - 12/02/06 01:58 PM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Feb 2001
Posts: 1,657
Neal Offline
Member
Neal  Offline
Member

Joined: Feb 2001
Posts: 1,657
Fragile compared to all metal. The late war planes were much tougher. Fokker DVII is metal tube throughout the main structure, isn't it? It takes more to deform let alone than break compared to equal mass of wood except in certain applications where the metal would would have to be too thin.

Consider the pre-stresses put on the frame through the rigging. They make it more rigid, keep the load bearing members aligned to take loads but at same time place another load on the members.

Jimmy Meissner (sp?) in Rickenbacker's memoirs ripped the fabric off his Nieup's lower wings twice but no one breaks a stick during maneuver that I remember reading of in the whole book. There were some wicked maneuvers too. Chasing a plane in a steep dive and he loops up, around, and comes in behind before the hunter reacts happened. Couple bullet holes in the right places ought to change that......

#2786364 - 12/03/06 02:33 PM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Dec 2000
Posts: 8,556
Li'lJugs Offline
Hotshot
Li'lJugs  Offline
Hotshot

Joined: Dec 2000
Posts: 8,556
St. Cloud MN USA
Quote:
Originally posted by PHilA:
I have a few WWI 3-channel R/C biplanes that fly on rudder and elevator alone and turns are made entirely with the rudder. The wing dihedral gives them stability in the turn. But the turns are relatively "flat" since there are no ailerons to bank the wings. Aircraft without adequate dihedral are harder to control on rudder-elevator control only because the dihedral helps correct any drop in wing tips--poor man's aileron. But planes with no dihedral do perform "flatter" flat turns as there is no wing dihedral to induce yaw in the turn. I have seen 3 ch. model triplanes with no dihedral fly in this manner. Full constant rudder will likely put them into a spin in a turn, so you "bang" the rudder gradually it to keep the model steady in the turn. The added lift of the three wings also helps. The real DR.1 and D-VII had very little dihedral so they should have been capable of very flat turns.

I may be wrong here, but aren't the aerodynamics much different on small (read: RC) airplanes, due to the Reynold's numbers? (I am drawing on 30+ year old memories here, so may be way off base.)


Hi, I'm Larry and this my brother Dayrle, and this is my other brother Dayrle.
#2786365 - 12/04/06 01:49 PM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Feb 2001
Posts: 1,657
Neal Offline
Member
Neal  Offline
Member

Joined: Feb 2001
Posts: 1,657
Smaller wings and fuselages for that matter need to be thinner to scale for those effects. That was the problem with using bird wings scaled up greatly to get the first curves. Had anyone noticed the differences in wings as birds got bigger it didn't seem to penetrate into wing design unless it was Gottingen the trend got through to. OTOH he could have just found out by experiment.

DrI had very short wings and fuselage just to improve the turn rate. Shorter wings will have less differential wing speed in any given turn as well. Less coupled bank per yaw.

The smaller the radius of the turn, the greater the difference in airspeed between either wingtip. Lift of the wing being dependant on airflow, there's gonna be some banking.

A thought... what kind of powerloading you get with RC? Compared to the real planes? Cause with enough thrust you can just walk all over the aero by pointing thrust where you want to go, right?

#2786366 - 12/04/06 02:09 PM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Feb 2001
Posts: 1,657
Neal Offline
Member
Neal  Offline
Member

Joined: Feb 2001
Posts: 1,657
The more I think of it, the more that if you could turn wings flat controlled even if only 45-90 deg, the better that might be as a combat maneuver.

If you get the mass of the plane turnning around the yaw axis then the torque the wings trying to bank would put should by gyro come out 90 degrees around and change... pitch?

#2786367 - 12/04/06 03:10 PM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Jan 2001
Posts: 3,538
PHilA Offline
Senior Member
PHilA  Offline
Senior Member

Joined: Jan 2001
Posts: 3,538
Still Lost in NJ
Not that this answers any questions, but it is interesing:

http://www.hq.nasa.gov/office/pao/History/SP-468/ch2-2.htm


"Save 'em the money. Hard times is coming" --Shemavon "Sam" Perperian (1900 - 2004)
#2786368 - 12/04/06 03:22 PM Re: Old Rheinbeck Airdrome: Fokker D7 flat turns in 8 seconds  
Joined: Sep 2001
Posts: 2,890
Warbirds Offline
Senior Member
Warbirds  Offline
Senior Member

Joined: Sep 2001
Posts: 2,890
As far as R/C planes flying like the real thing, I fly R/C scale and have flown many R/C WWI planes. The last was an electric powred Dr1.

They fly very similar to the real job and even down to the very small carry the traits of the real planes fm.

The Dr1 can turn circles on itself and almost catch it's own tail, looks like my dog does when he thinks his tail is a cat \:\)

The Dr1 will also do a cool flat turn if you coordinate the rudders with aileron to keep it level. Not sure how tight, winter here now so can't go out and test for you. It seemed tighter than most ships I fly for sure.

I also fly WWII warbirds and they unfortunatly also take on the traits of the full size ship. Hard to fly and will snap if you sneeze.

My qualification in this subject is my site http://www.rcwarbirds.com


"A time when America was great,,when the chrome was thick and the women were straight" - Micheal Savage

"If you really want to experience flight in this life then you have to strap a DC-3 to your ass." - Buffalo Joe McBryan President & Captain Buffalo Airways
Page 2 of 2 1 2

Moderated by  RacerGT 

Quick Search
Recent Articles
Support SimHQ

If you shop on Amazon use this Amazon link to support SimHQ
.
Social


Recent Topics
Carnival Cruise Ship Fire....... Again
by F4UDash4. 03/26/24 05:58 PM
Baltimore Bridge Collapse
by F4UDash4. 03/26/24 05:51 PM
The Oldest WWII Veterans
by F4UDash4. 03/24/24 09:21 PM
They got fired after this.
by Wigean. 03/20/24 08:19 PM
Grown ups joke time
by NoFlyBoy. 03/18/24 10:34 PM
Anyone Heard from Nimits?
by F4UDash4. 03/18/24 10:01 PM
RIP Gemini/Apollo astronaut Tom Stafford
by semmern. 03/18/24 02:14 PM
10 years after 3/8/2014
by NoFlyBoy. 03/17/24 10:25 AM
Copyright 1997-2016, SimHQ Inc. All Rights Reserved.

Powered by UBB.threads™ PHP Forum Software 7.6.0