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CG for Vailly 90.5 FW 190

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CG for Vailly 90.5 FW 190

Old 08-29-2008, 02:37 PM
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rzapp
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Default CG for Vailly 90.5 FW 190

Hi
I'm Looking for any Info on the CG for the Vailly Fw 190. I've Purchased the FW complete and have been going through it all and at the point now trying to balance this big bird. there is no mention of the CG on the plans that was sent with the plane and I've gone through all the forums looking for this info. I've found a little but it was pretty vague .

so my questions are: Where is the cg supposed to be with reference to measurements at the wing saddle and wing or wher are the hard points supposed to be when doing this?
Is it best to balance the plane on it's back at these points for this,, I've done it both ways but for the FW I Want to make sure?

Thank you
Rick
Any help would be appreciated
after this she is ready to fly!!!

Old 08-29-2008, 09:19 PM
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rzapp
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Default RE: CG for Vailly 90.5 FW 190

thanks for looking

I talked to Roy directly at Vailly aviation and he gave all the info i needed, a great guy to talk to, he even pulled out the plans as reference and answered all my questions.

thanks Roy

thanks
rick
Old 08-29-2008, 11:36 PM
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rrudytoo
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Default RE: CG for Vailly 90.5 FW 190

rzapp,

One thing you need to be aware of is that your Fw 190 will require about 15 degrees of flap deflection on take off. Without using flaps, you run a large risk of stalling your Focke Wulf right after it leaves the ground. Once you build up some air speed you can bring the flaps up.

Al
Old 08-30-2008, 12:06 AM
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Default RE: CG for Vailly 90.5 FW 190

thanks Al
presently I have aprox 20 degrees for take off flaps an 45 degrees for landing.

rick
Old 08-30-2008, 07:30 PM
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Default RE: CG for Vailly 90.5 FW 190

Alright, Rick! You're on it!!!!

Al
Old 08-31-2008, 09:50 AM
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rzapp
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Default RE: CG for Vailly 90.5 FW 190

thanks Al

Roy's info was great but I'm still having problems balancing this big bird. Roy says to balance it right side up with wheels down using the measurements up in the wheel wells to balance it but this is pretty difficult to do. is there alternatives to check and set the balance point.

Rick

Old 09-02-2008, 09:25 AM
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Default RE: CG for Vailly 90.5 FW 190

Rick, I have a FW 190 from Vailly as well. I balanced mine like I do all low wing planes, inverted with the landing gear retracted. I balanced per the plans at the farthest forward location. This way it would be slightly nose heavy.

If you remember 12-15 degrees flap on takoff, it should fly great.

Jay
Old 09-02-2008, 04:52 PM
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Default RE: CG for Vailly 90.5 FW 190

Rick
Sounds like you have all the info.................................nerves are getting the best of you. Lets get her into the air. I need to chase someone with my P-47

Craig
Old 09-02-2008, 05:13 PM
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rzapp
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Default RE: CG for Vailly 90.5 FW 190

hi Craig not just nerves just want to make sure, and also, who will chase who? almost ready like i said just want to make sure it"s such a great looking bird Roberto did a great job and i want to fly it for a long time. I see you started posting again on the corsair build that's great, less house work and more hobby work.


rick

see ya at the field
Old 09-02-2008, 09:00 PM
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Default RE: CG for Vailly 90.5 FW 190

I'm curious about this flap statement for take-off. I had a Vaillancort FW190 and never used flaps for take-off and NEVER had an issue with take-off. Why do you say you need flaps for take-off? While I do it on several birds (flaps on take-off), I don't think many folks do. I can attest that taking off with some flaps does, in fact, make the plane more solid for take-off after clearing ground effect...it doesn't seem to want to drop that bit as it does with no flaps. But, flaps on landing made it land like a dream

Jeff
Old 09-03-2008, 12:17 AM
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Default RE: CG for Vailly 90.5 FW 190

Jeff,

Gotta question for you: Do you fly off an asphalt runway or grass? The reason I ask is a hard surface lends to less rolling resistance and, therefore, allows for faster acceleration during take off. I'm just wondering if a hard surface would allow take offs without flap deflection. Our club has a grass runway that can offer a lot of rolling resistance at times making for a loooong take off roll. Flaps are a real help here. From what I have seen, the Vailly 190 definitely requires flaps at our field.

Al
Old 09-03-2008, 07:35 AM
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Default RE: CG for Vailly 90.5 FW 190

I spoke with Roy at Vailly Aviation a few years back while finishing my FW190. He recommended 12 degrees flap on take off. This appears to stabilize the plane at take off speed reducing the possibility of a tip stall. This setting worked perfectly on my FW190 and proved to be true when I forgot to use the flaps on my last take off.....[:@]

Jay
Old 09-03-2008, 10:18 AM
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Default RE: CG for Vailly 90.5 FW 190

I fly from both, but mostly grass. I agree flaps make the take-off more stable....no question there.

Jeff
Old 09-05-2008, 11:18 AM
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Default RE: CG for Vailly 90.5 FW 190

Interesting....could someone explain from an aerodynamic perspective, why split flaps as found on the FW-190 improve low speed stability? I can see the benefits of plain flaps and especially fowler flaps....but am having difficulty reasoning the advantages of split flaps in this situation.
Old 09-10-2008, 12:38 PM
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Default RE: CG for Vailly 90.5 FW 190

No responses?...does this mean no interest in understanding whether utilizing some degree of split flaps on take off provides a noticeable improvement in slow speed stability...or does this mean no one can provide an aerodynamic explanation? The reason I ask is that the effect of split flaps is almost entirely drag. Take a look at old, (and new) film footage of aircraft with split flaps, (zero,Spitfire, DC-3, B-17, etc), during takeoff. I recently had the chance to view footage of Zeros taking off a carrier deck...no flaps, yet in the same sequence of footage, Vals taking off did have flaps extended...but they have plain flaps....not split flaps. One could easily draw a conclusion that if additional stability at low speed could be gained by extending split flaps, then taking off from a carrier deck would certainly qualify.
Old 09-10-2008, 04:40 PM
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Default RE: CG for Vailly 90.5 FW 190


ORIGINAL: L16pilot

No responses?...does this mean no interest in understanding whether utilizing some degree of split flaps on take off provides a noticeable improvement in slow speed stability...or does this mean no one can provide an aerodynamic explanation? The reason I ask is that the effect of split flaps is almost entirely drag. Take a look at old, (and new) film footage of aircraft with split flaps, (zero,Spitfire, DC-3, B-17, etc), during takeoff. I recently had the chance to view footage of Zeros taking off a carrier deck...no flaps, yet in the same sequence of footage, Vals taking off did have flaps extended...but they have plain flaps....not split flaps. One could easily draw a conclusion that if additional stability at low speed could be gained by extending split flaps, then taking off from a carrier deck would certainly qualify.

The Spitfire and Zero had very light wingloading for their power. They basically didn't need extra lift like the Val would. The Val would have been humping a load as most dive bombers do on takeoff. Spitfires didn't use flaps for takeoff as a rule. The takeoff checklist specifies Flaps = Up. I've never seen anything on the Zero, but pretty sure it wouldn't need them either. The Spit did get heavier through the different marks, but also picked up a bit of horsepower to go along with the weight.

With details that have multiple effects, it's dangerous to assume they explain one effect in one situation. Drawing conclusions from one single aspect of the flight envelope is pretty dangerous. For example, probably the most important thing about taking off from a carrier would be acceleration. And if the airplane didn't need additional stability, why drop split flaps since they'd have little or no other positive contribution and would slow acceleration.
Old 09-10-2008, 04:46 PM
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Default RE: CG for Vailly 90.5 FW 190

BTW, for ANY airplane, model or fullscale, it's really simple to get an absolutely reliable CG specification by figuring it out. And you don't even have to do any figuring.

Look at the 9 measurements this application requires. You can do 'em with a yardstick in less than 5 minutes. Plug those into the application and it does the figuring. It works perfectly.

http://www.geistware.com/rcmodeling/cg_super_calc.htm

You will have to provide a decision. The input requires a Static Margin. If you run the application with 10% and then 20%, you'll get a very good CG range to use for your first flight.
Old 09-11-2008, 07:26 AM
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Default RE: CG for Vailly 90.5 FW 190

Da Rock:...I do not disagree with your assumptions, but they are just assumptions. Now, your assumptions may be true, but what I tend to see in this hobby is a lot of conjecture that soon becomes "fact" because someone else says so. This is not a bashing or attack...just trying to open the door for factual aerodynamic principles of the full size aircraft so that we may apply them to the smaller versions we create as modelers.
Old 09-11-2008, 12:48 PM
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Default RE: CG for Vailly 90.5 FW 190


ORIGINAL: L16pilot

Da Rock:...I do not disagree with your assumptions, but they are just assumptions. Now, your assumptions may be true, but what I tend to see in this hobby is a lot of conjecture that soon becomes "fact" because someone else says so. This is not a bashing or attack...just trying to open the door for factual aerodynamic principles of the full size aircraft so that we may apply them to the smaller versions we create as modelers.

You want factual aerodynamic principles from full size aircraft industry? No problem. Check out geistware.com (the link in my post above). It's not conjecture. It uses almost exactly the identical formulas the aircraft industry and fullscale designers use and have used since they were accepted as "fact".

No bash intended. Lot's of people don't know what is fact or BS.

And you will also see a lot of aeronautical terms on geistware. They didn't make 'em up, they just used them because they're what the industry uses. It's a good place to actually find out what designers do. Lot's of our modeling experts don't consider tail moment or even the tail's contribution to pitch stability. With that application, you can actually see (if you play around with the numbers a bit) how all those areas and distances and such affect pitch stability.

It's really kewl that modelers do have such a tool to use. When I worked at Lockheed, you had to be one of the A.E.s to have something like that at hand.
Old 09-11-2008, 04:00 PM
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Default RE: CG for Vailly 90.5 FW 190

Actually, if anyone is interested in how designers figure out the acceptable CG range for a new design, look at the notation to the right on that calculator page at geistware.com. Those formulas are used by the entire industry. Fullscale and model designers, and by those of us who know about them.

The pitch stability of any layout depends primarily on only a few things. There are a BUNCH of modifiers to those things, but they seldom affect the CG location significantly. So if you look at the formulas and study how they're used you'll basically see what's taught in Aero Design, Pitch Stability 101.

And you'll see that the major players are the area of the wing, it's chord, the area of the horizontal tail, it's chord, and how far back the tail is from the wing. Everybody and anybody who wants to figure out a safe range of locations for the CG can work out those values for his model or new design (be it a new Boeing or an existing model) and plug them into the formulas and come up with reliable numbers. Or he could plug the measurements into the Geistware application and hit the button.

Ain't no guesses or opinions in them thar formulii. Just the aerodynamic principles that're in use today.

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