...Heaviest...

[Bootlegger]

 Guy's what is the heaviest that you have seen a model with approx 575 sq in wing ares powered by a Tiger 60 fly a decent pattern
  I have a PORKY model with these dimensions that weigh's 75 oz !!!
 I plan to fly with 63' .018 lines .  Any suggestions will be 'ppreciated.........

[Paul Smith]

I can't venture a guess about the heaviest 575 square inch model.

But I can say that 45 ounces +/- 5 is more the norm. 

If that 75-ouncer looks good, hang it up.  If not, strip if down and find the weight.   Heavy planes have been rehabed by liposuction, Jenny Crank, and boot camp.

[Robert McHam]

I second paul's opinion. It may fly, but I doubt you will ever gain any satisfaction from trying to do so.

As a second thought you may even forget about trying to put this monster on a diet. Unless over half the overage is in the finish, you would work yourself to death trying to trim the weight.

Heavy planes are just no fun to fly.

Robert

[Marvin Denny]

    I would imagine that the ST 60 is a goodly portion of the weight and to get it to balance, I would also assume that there is a goodly amount of weight in the tail to get the balance where it belongs.  Reduce the engine weight to say Brodak 40   size and then remove the tail weight til it balances and you probably will have a plane that could perform reasonably.

  If you are just looking for a Guinnisses book of records thing like the heaviest plane to do the pattern with less than 600 square inches of wing---     Well   go for it

  Bigiron

[phil c]

Not knowing what in particular it is, it probably has roughly Nobler dimensions, so the  ST is 3-4 oz. of extra nose weight.  Add at least an ounce of tail weight, more likely two.  The covering/paint job should be in the 6 oz. range.  Careless work can easily double that.  There is a potential 12 oz that you can get at without rebuilding major parts.

Heavy balsa- the basic airframe should be around 21 oz.  Heavy balsa can easily add 10 oz. to that,but you can't do anything about it without building a new plane.

I'd guess the best you can do is get it down to 62 or so, which is still very heavy for a 575 in plane.  Something like a PA or RO 40 would have the power to pull it.

[Bootlegger]

 Guy's I really missed the wing size on this posting... The wing is 677 square inches...  I appologize for the error, and I thank all ya'll for your suggestions.
  Now, the same questions apply with the correction in wing area....

[Ward Van Duzer]

Can't really vouch for wing area, but I was at the team trials a few(?) years back where a former world team member, and future nats winner had a P.M. in (I believe) the 90 oz. range. That was the year they decided to go by FAI rules for line sizes to be determined by airplane weight. Man did this guy scramble. Some said he weighed in with no fuel tank. I Dunno...

By the way, if you've never been to witness a team trial, you're missing a real treat! Way better than the Nats.

w.

[phil c]

It'll be easier to fly with a 677 in. wing, but 75 oz. is still pretty heavy.  Noticed that Werwage's P47 had about 750 squares and weighed 54 oz.

If you do have an overweight plane, the easiest fix, without completely rebuilding it, is to extend the wing span.  Even just a couple of inches of extra span one each wing will make a big difference, a lot more than adding the same wing area to the flaps.  A heavy span loading makes the plane slow down even more than usual, which causes all sorts of problems trying to do maneuvers.

[Gary Hajek]

I have watched plenty 0of 75 ounce airplaines at the nats make it past top five with super tiger 60 they fly great  try to fly at 5.2 good luck

[Bill Little]

IIRC,  Some of the early SV-11s (660-670 sq in??) were built around 70 oz. with the ST 60 up front.  They were very capable, but would have possibly been better a touch lighter.

My Geo Juno (around 660-670 sq.in) was 54 oz. new w/40VF.  It has never had a problem!  On the other end, Champione's orange United is 84 oz., or more!

[proparc]

I didn't want to weigh in on this thread because of all the complex factors that go into plane performance. But that said, IN THIS CASE, YOUR PLANE IS DEAD!!! 

I personally feel that too much is made of the weight issue in stunt because of a lack of basic understanding of stunt aerodynamics and power to weight issues. Patternmasters are NOT designed to fly at 45 ozs or, Nobler weight. Noblers cannot handle 75 ozs or, Patternmaster weight. Noblers simply cannot handle Merlin 75's or Saito 72's. You will be lucky if you can get a Patternmaster to taxi with a LA 46.

All to often, we tend to just look at the square inches of a ship and make summary judgements about it's weight hauling capabilities.  The airfoil on Jim Greenaway's creation was designed to generate tremendous pressure.  It's not just the fact that the plane has 750 sq of area, it is the fact that the airfoil in question is generating this pressure across the whole surface of this particular planform.

I can make my statement about YOUR plane because not only do you not have sufficient surface area to handle that weight, but, you DO NOT HAVE THE AIRFOIL TO deal with a weight like that no matter how much power you put in!!  My advice in this case; TOSS THE PLANE!!!

Do you have to learn to build lighter? No - just learn to build the RIGHT PLANES for the job.

[Mike Ferguson]

Do you have to learn to build lighter? No - just learn to build the RIGHT PLANES for the job.

Exactly.  And "wing area" isn't always giving a true picture of what's going on.

The Patternmaster and the Geo-XL both have over 700 sq. inches of wing area.  Both are big boys.  But the Patternmaster has a very thick airfoil, and the Geo-XL is very, very thin.

Put a ST. 60 in a 70 ounce Patternmaster?  You'll probably be fine.

Put a ST. 60 in a 70 ounce Geo-XL?  You're dead.

[Bill Little]

Exactly.  And "wing area" isn't always giving a true picture of what's going on.

The Patternmaster and the Geo-XL both have over 700 sq. inches of wing area.  Both are big boys.  But the Patternmaster has a very thick airfoil, and the Geo-XL is very, very thin.

Put a ST. 60 in a 70 ounce Patternmaster?  You'll probably be fine.

Put a ST. 60 in a 70 ounce Geo-XL?  You're dead.

You're exactly right, along with proparc.  I didn't clearly define what I was thinking in my post.  As to airfoils, that is a, if not THE defining criteria to how much weight a plane can handle.

One of our illustrious brothers in balsa here built a Werwage design a year or so ago.   We discussed the build since I had done a couple of them.  He mentioned thjat the Werwage designs he had previously flown had been less than stellar.  But he mentioned the weights of them, and that was the key.  A plane that Billy designs has to be on the light side of the scale.   His airfoils are not intended to carry a lot of weight!  They do not fly like they should if they get the least bit porky.

Your comparison of the PM and Geo XL is right on.  There is so much difference in the design parameters!   Same with the scale planes of Mr. Rabe and Mr. Burn.  A whole 'nuther set of aerodynamics!   All of these planes are exceptional if built as they are designed.

It's all gravy!
Bill <><

[NED-088]

That was the year they decided to go by FAI rules for line sizes to be determined by airplane weight.

F2B never dictated line size...  But it's the pull-test force that depends on the airplane weight. It's up to the pilot how to meet that requirement. The only right way, IMHO.

I fly ST 60's on 70 ft. .015  and G21-46 on 70 ft. .013 Laystrate....

[Gordon Tarbell]

Where can laystrate line be bought? Is it the same size and weight as the normal 7strand stainless that is normally used?