I would be interested, if anyone knows. It seems like some kind of proportional mixing (or whatever you call it) of rudder or left and right elevator half would allow you to mix out the snap. Comments?

In a snap one wing has stopped flying before the other (or in some cases the tail stalls before the wing causing loss of directional stability...very common in WW-2 planes). Some washout at the wingtips can help somewhat, but a cap W/ quad. tapered wing is going to stall at a much higher speed than a sport ship with a hershey bar type wing. Once it happens all you can do is neutralize controls add power, gain some speed over the wing agian and hope you have enought alt. to recover. Notice the new "sport cap" from H-9 has a very large tail and larger wing to give it better slow handeling traits.
Brian

To my knowledge there is no way to "mix out a snap"
The only way out of a snap is more airflow over the wing or less angle of attack (hi speed snap).
Im no expert but I would say the shorter distance between the stab/elevator and the wing has a lot to do with it as well

Splais:

Wrong. These planes were designed that way to allow the full
size competition planes to fly on the edge of a stall to allow their
quick snap maneuvers. The small tips don't hold the lift as does
the center section. I've found reflexing both ailerons up 1/8 to
3/16" creats the washout to prevent the tip stall. Also, too much
elevator travel made my Caps snap abruptly. I coundn't figure
out why the plane would fall out of a sharp upward inside loop.
Once I put in the washout, I lost some of the quick rolls but it
sure did make landings a lot more enjoyable.

OK if washout is the answer, why not just build a little washout in the wing and be done with it?

Probably because it easier, thus cheaper, for manufacturers to build straight wings.

Most planes have wash out built in. Remember wash out raises the stall speed only a little. The way it works is any wing in which the wing stalls at the tip first will usually stall with a nasty snap. If you put wash out in the wing tips if one tip begins to stall the wash out "WARP" will cause the still flying wing to go down and help make the stall less violent, But a quad tapered wing will always stall tip first. That is why we progress to "advanced" planes when we want to challenge our skills.
One of the snappiest plane I have ever flown was the Kyosho 40 size Cap 21.....not only did it have a nasty stall it also gave almost zero warning before it stalled. One minute you were flying the next minute you were spinning for the ground. It sure kept me on my toes. Finally lost an engine...... tried to make the field..
.....well it is gone now. I still have one, I plan to build one day.

Anyways the key is, big thick wings that are lightly loaded have a high stall speed and visa versa.
Brian

Since the wings are built in a jig, it wouldn't make any difference (be it easier or cheaper) to set the jig up to yield wings either straight or washed out.

You wouldn't want an aerobatic plane to have washout built in. An aerobat should fly as well inverted as it does right side up, and any built-in washout becomes wash-IN when you're inverted, and might exagerrate any snap tendency.

Quote:

Anyways the key is, big thick wings that are lightly loaded have a high stall speed and visa versa.

Now THERE'S the ticket!!

finally a reason that makes sense read people caps are notorious for snapping fly the plane hot enough u will be fine

I too had a friend of mine put his h9 matt chapman cap in last week.He said the same thing,one minute it's flying,the next it's firewood.I warned him about getting to slow,his reaction was to add power and up elevator,tsk tsk tsk.

I've heard that spoilerons will make the stall speed lower while increasing the speed where it will snap....

True? or Not?

Has anyone else noticed how conservative the Mfg's of Caps. are on engine size recomendations but too generous on cg. and
elevator throw. Each Cap I've owned didn't calm down till I moved
the cg 3/4" ahead of suggested location. The worst I had was a
Lion ARF Cap 21 60 size. I was 1/2" ahead of cg given and it
only lasted 20 sec. from shallow lift-off when it went into a nose
up stagger then a pile of foam board. The G/P 231 runs a close
second. Give me an Extra or Edge any day.

Randy

Too much elevator throw in low and slow situations where it is not needed. J.M.H.O.

Scott

Yup to much elevator will get you each time....Years ago I had a Midwest Fun Scale ME-109......At first I thought it was one of the snappiest planes out there, always on the edge of a stall when I slowed it down to land. Even had it snap a couple of time on final approach. Well after a rebuild "Light dawned on marblehead" and I reduced the elevator throw by 50%....and what a sweetheart it became. I could slow it down to a crawl and it wouldnt even begin to stall...........
Brian

Allright, If its just the wing, how come a cap 232 is snappier than an extra. They have the same wing. Theres got to be something more than just the wing

So, nobody knows about the spoilerons? hehe...I'll ask it as a general topic and see if I can rope in the old timers.

Thanks!

I'm no expert, but, the first thing that comes to my mind is that since a snap occurs because the wing stalls, it seems to me that anything that makes the stall speed lower must also make the snap speed lower.

Another thought (boy, that's 2 in one day, better sit down and rest) is that while spoilerons are great while the plane is rightside up, what happens when it's flown inverted? I'd want an aerobat like the H9 Cap to fly the same both ways.

Take a look at the stab size on a cap and on an extra..
You will notice a difference. That will effect a way a plane snaps also.

Cg can make a plane snap more or less.. On both my cap and extra my cg is set so critical that if fly droppings fell on the tail the planes would be unflyable!
Novice flyers should set their CG 1/2 inch ahead of the recommened cg starting point for the first bunch of flights till they get a feel of the plane's snap tendencies.

"I've found reflexing both ailerons up 1/8 to
3/16" creats the washout to prevent the tip stall"

Is this a good Idea? From what I am picking up on this thread is to start out with a forward cg, ahead of recomended, cut the elevator travel, and reflex both ailerons. This would be a safe starting point. Is this right or is this overkill?

A snap roll is stall maneuver. It is not the same as a tip stall. The best way to prevent a snap is to not stall the wing. Reducing elevator throw will help. From straight and level flight, pull into a loop with full deflection on the stick. If the plane doesn't snap at the top of the loop add throw until it does. Not reduce the throws slightly until it can complete a full deflection loop without snapping. This should help with any inadvertent snaps.

When I set up my planes, I use the rationale that within the mfr's suggested range for the cg, the actual placement of the cg determines how EFFECTIVE the elevator will be, rather than determines whether the plane will be docile or squirrelly. A forward cg will make the elevator less effective, and a rearward cg will make it more effective (thus requiring less elevator throw to achieve the same reaction). If you have a plane flying well at the mfr's farthest forward suggested cg point, you can move the cg back to the mfr's rearward suggested cg point and also DECREASE the elevator throw, and not notice ANY difference in flight characteristics. The key is understanding that a forward cg makes the elevator less effective thus requiring more movement, while moving the cg back makes the elevator more effective, thus requiring less movement to do the same thing. One place where you will notice a differences might be in landing speed. The forward cg tries to drop the nose, and since the plane has a tendency to go downhill, it's harder to get it to slow down for a landing. As the speed decreases, the already less effective elevator becomes even LESS effective in flaring, and the plane is said to land hot. A rearward cg doesn't tend to fly downhill so much, thus making the speed much easier to control in landings (better "brakes".

To sum up, the cg doesn't make the plane more snappy, TOO MUCH ELEVATOR THROW does. The more rearward the cg, the LESS throw is required. I set mine up to use as LITTLE throw as possible, consistent with clean snap roll and spin entries. This way, it snaps when I want it to, rather than when IT wants to.

I have the GP Cap 231EX ARF (discountinued, aka Splat 231) and have tried the spoileron approach. All I can say is YIKES! With the "flaps" down it will slow the stall speed, but it's REALLY tipsy.

So, if you are doing this to aid in landing (I fly at a really short field), my advice is not to do it... I learned my lesson by breaking the gear plate out!

However, it does help in flatten a spin -- even better, move both ailerons up and try and inverted flat spin!

-Chris

Chris: I guess you and I took that reflex thing different. I took it to mean that the alerions were up not down. I figured this because for washout the wing tip is higher at the trailing edge, thus the up alerions. I didn't take it to mean flaps. Was I off base or what.

I meant spoilerons, and on landing....

So, ailerons up, which also brings the nose up a bit, but decreasing the tendency to tip stall....or so I've heard...

Flaps on landing (ailerons down) decreases the stall speed, but tends to increase the tendency to tip stall, or so I've heard...I was hoping to understand is spoilerons on my sons Sig CAP231EX would be a good thing...

That being said, Tim_Indy gave a great explanation about CG and elevator throw, and we'll use a forward CG and control elevator throw, for the first several flights.

Thanks!