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Tip stalls..... any fixes?

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Tip stalls..... any fixes?

Old 06-17-2005, 07:06 PM
  #26  
combatpigg
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Default RE: Tip stalls..... any fixes?

To answer NAVY18s' original question, I know you don't want to hear about making the wing larger, but it wouldn't be that difficult to add 3" of tip chord. The ribs in question would have to be stretched the required amount. There are already so many other good, no GREAT flying .40 sized models out there, why beat a dead horse anyway?
Old 06-17-2005, 09:27 PM
  #27  
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Default RE: Tip stalls..... any fixes?

Combat Pig and Dick both address the same fix in different ways. Get the wing loading down and your problems get easier and easier to deal with. Bigger wing and lighter both get it there. That Red Bull website reiterated this idea in a few places very briefly. Cool looking site, though.

Please resist the urge to curse, flame, degrade, insult or embarrass someone in your post.

G[&:][&:]
Old 06-17-2005, 11:14 PM
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Default RE: Tip stalls..... any fixes?

This discussion is timely because one of our local modelers showed me an .25 sized EXTRA that he had framed up from RCM plans. We both, from past bad experience with highly tapered and fairly hefty craft think it is a snap roll on final waiting to happen. I offered to redo the wing for him. I've also got him sold on using mini on board gear, which if you add it all up is a significant weight reduction, and I will make a CA / FG cowl from 4 layers of 1 oz cloth, which is somewhat lighter than FG and resin. The control surfaces will be done with SPIDERLINE, except for the ailerons which will be 2-56 rods, with CF tube slid over them. He has been working on CF gear for it, if he can't come up with something there, there are commercial CF gear suppliers out there. You can build light, but it takes effort. The quick way is usually the heavy way.
Old 06-18-2005, 05:22 AM
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Default RE: Tip stalls..... any fixes?

After watching the giant scale aerobatic ships and the current crop of the better 3D ships turn and land at walking speed it's obvious to me that Dick Hanson knows what he's talking about !!! the thing they all have in common is that they are light - you can try and make these 40-46 size planes ( 500 to 600 sq inches at 5 to 6.5 lbs ) perform and land like the bigger light machines but in my opinion it's just not gonna happen !!!

Dick, I enjoy your comments and the info that you provide so keep them coming - I can understand folks disagreeing with your viewpoint but why they have to get rude and sarcastic is a mystery to me.

WB2SXN

Oh by the way I enjoyed the website on the Edge - It was obvious to me what the message was - light flys better !!!
Old 06-18-2005, 03:18 PM
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Default RE: Tip stalls..... any fixes?

A .40 sized plane in this size range flies pretty good at 4.5 pounds. A $30 digital scale would be a good investment for both scratch and kit builders who are interested in building light.
Old 06-18-2005, 04:49 PM
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Default RE: Tip stalls..... any fixes?

"...flies pretty good at 4.5 pounds..."
Unfortunately the GP Extra 40 comes in at 5.75 pounds, according to their website (which may well be on the optomistic side). So what can a buyer of this model do? If there is a real problem with tipstall on landing, it is going to be hard to get the weight down to your 4.5 pounds so, it is worth considering some of the aerodynamic options suggested on this thread. At this size, aerodynamics plays a role so it is worth trying some of the wing modifications suggested.
By the way, I have a digital scale and love it.
Allan
Old 06-18-2005, 06:11 PM
  #32  
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Default RE: Tip stalls..... any fixes?

Sometimes all a kit is useful to me for, is the planes' outline. The parts themselves are good for use as templates, so lighter wood and or deletion of the part [like ply doublers, triplers, spruce spars, oversized pieces, full sheeting, etc.] can be done. Forget about using 1.5 oz servos, 2 oz RX, 3 oz battery, heavy LG and wheels, and last but not least, a heavy .40 that weighs a pound, there are light weight .40s out there that weigh 3 ozs less and can generate 6 pounds of thrust with a 10x5 prop. It is a bunch of little things that add up to a light model. A good way to learn light techniques is to get into 1/2A or small electric building, then apply what you've learned to the bigger stuff. Another way is to learn how .60 sized pattern planes are built, these techniques down size nicely into .40 sized models.

The aerodynamic fixes to an overweight models' problems don't have much power at typical approach speeds. At 15 to 20 mph, a 5 inch chord wingtip, with this much weight heaped on it, and no matter how much hocus pocus is thrown at it, is just going along for the ride.
Old 06-18-2005, 06:51 PM
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Default RE: Tip stalls..... any fixes?

Per zactly--
I have my own set of aerodynamic rules -which are not looked upon kindly by some - but they work.
A -If the plane is too heavy, the CG does not matter -(nor do any airfoil fixes .)
Meaning --If it is too heavy for intended use - Nothing will fix it.
B-If it is light enough - NONE of the items such as airfoil/ cg etc., mean much.
Proven fact- we have really explored this one -not from a referrence book -but from hands on experience.
C- the only things that really matter are wingloading and power loading .
Unless one is into aerobatics -this sounds very strange .
If one IS into aerobatics -this is the Golden Rule.

If you really dig into why the "why" the advent of flaps, special airfoils etc., you will see that the work (necessary) was done for a specific reason - almost always - to accomadate a load and power availability.
Some full scale stuff had a take off speed /max speed and landing speed all within a very tight envelope.
On our models such as the subject model - the envelope need to be broad - to make flying it FUN.
In this size the only proven fix is to reduce loading .
increasing power is nice but not as important.

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