Adui

OK, so what exactly is a snap roll, as apposed to a basic aileron roll?
I did a quick web search, and found a site describing the stick movements on the TX to get one, but not what the plane looks like when doing it. (It also warns that the plane is subjected to high G's and to not do this if your bird can take the stress)

Side note: can the H9 Arrow do one safely? (dont want to try it only to watch my wing fold up and lawn dart...)

MinnFlyer

My Feedback: (4)

It is a fairly violent roll where the tail of the plane does a sort of circle around itself as opposed to just spinning on the roll axis as it does in an aileron roll.

It can be safely done with your Arrow, but practice up HIGH - The probem with doing them is knowing how long to hold the control input (It don't take long) or you can do one-and-a-half and wind up inverted

Adui

Thanks Minn, on both counts!

Im probably going to give it a try next time I go flying, WAY WAY up high at first though LOL!

Hmmm, so much for picking just a couple maneuvers to practice to perfection.. Ah well, its all fun so I got to try it all!

Oh, for those I told my second plane would be a 4* it has changed. While thats a good kit, and likely will be my first Balsa build, circumstance, cost, and curiosity have led me to build a SPAD Debonair, and a SPADStick. The Deb will be my kids airplane to learn on and to fly, the Stick will be my next toy!! Deb is about half built, hopefully she flies as well as other SPAD Debonair owners say there's does.. Stick will be built once the Deb is finished.

Jburry

Hey Adui!

Snaps are performed by inputting full elevator (up or down, some planes like it better one way than the other), and as the wing stalls, full rudder (either way). The plane will roll violently with the tail sorta thrown out as it goes around.

I have a .46 size mustang. On aileron rolls, she's good for one or 1.5 rolls per second. When snapped, she'll do about 3-4 per second. At 100mph. The pilot's brains are extruded thru his nose and splatter the panel and canopy.....

I have a 25 size 3 channel trainer (rud/ele/throttle only). It will do pretty good positive snaps, but won't snap negative (down elevator). Something to try for you. Take your trainer up high (5 mistakes....), and at moderate throttle (aerobatic cruise, about 60-70%), apply full up (high rate) followed immediately by full rudder, and hold both. First the plane will do a snap roll (or 2 or 3, depending on speed and momentum). Keep holding your inputs. It will transition into a spin as it plummets to the ground. Reducing throttle will reduce the spin rate (this is a good idea). Applying opposite aileron (ease'em in) will tend to flatten the spin. Exit the manouvre by neutralizing the controls, applying opposite rudder if required (not likely required on a trainer), advancing the throttle, and easing out of the resulting dive. Plan to exit at 2-3 mistakes high at first. Exits at 10-20' are EXCITING!!!

Have fun!

J

Nathan King

Is the Beginner's Forum going through a transformation? I've never seen so many aerobatics questions in a row on here. [sm=confused.gif]

Adui

LOL I dunno, Im still what I call a beginner, but have these nagging questions..

Should I be asking in another forum?

(My real conundrum is the fact that I am teaching my kids, and yet I feel like I am still a n00b myself!)

Nathan King

No, I don't mind. By all means, continue to ask questions. I'm just curious since there seems to be a trend here.

The only bad question is one that is thought about but never asked.

AstroDad

the arrow will do wonderfull snap rolls!

One thing I noticed with my arrow is that the tape holding the 2-halfs of the wing together was torn shortly after I started doing snap rolls, so keep and eye on that if you taped your wings together vs. epoxy them. I assume the tape was torn due to the great force. I have since used regular tape down the center joint and also covered it with a 2nd layer of packing tape. I also inspect the tape before each flight as part of my checks.

I think the snap roll will really "wow" you. I cannot wait to hear what you think about it!

my arrow snaps very well in multiple stick configurations, but seems to more easily maintain altitude with rudder right, elevator up, and aileron right. so put the left stick to the right, and the right stick in the bottom-right corner. In this configuration I can keep it more or less at altitude without much down pitch for probably a dozen rotations. it is really cool to see.

Even though it seems to maintain pitch better in that configuration it seems to do a tighter snap with the rudder stick left, aileron right, and elevator down. so sticks in top oppisite corners.

more throttle makes it roll even faster and of course looks more stressful on the airframe.

might not be best practice but to stop the snap-roll I usually just release the sticks and let them snap to the center. even when I am not really paying attention the arrow almost always seems to stop snaping in somewhat of an upright position.

Jburry

The aileron input shouldn't be needed to snap, in fact, most think it makes a snap look "messy". It is required to convert a spin to a flat spin.

If you don't need to separate the wing halves, you really should glue them. It makes a much more durable wing.

I like aerobatics basics questions in beginners too. A beginner asking good questions about aerobatics is well on his way to being an old pro. Hang in there Adui, there's lotsa fun to be had yet! I remember discovering the snap roll. It was by accident. I fed in too much down elevator during the inverted portion of an victory roll with the 'stang, climbing out after a 100mph+ pass, and "What the He77 was that!!!!!!???". Then I did a half dozen more......

J

AstroDad

you are suggesting try to do it with just rudder and elevator?

Adui

Astrodad;

Im mildly surprised you didnt glue your wing halves. My instructor, (My first one years ago) told me to do that first thing! Mine is both Epoxied together and taped. Of course, my plane got reinforcments elsewhere, but most were after a, Ahem.. hard landing.

Jburry

Yes, most planes will snaproll with just elevator followed immediately by rudder. Full up, hard left, takes about 1/8 second.... *SNAP* "WOW!!"

J

jetmech05

I've been skipping over the answers here....I didn't see where anyone explained the difference between a snap and an aileron roll..The snap roll was explained to you already...the aileron roll is a nice gentle roll where the airplane just rotates around the roll axis only...just like if you were holding the spinner and let the airplane rotate on the crankshaft...I've been told that if it's done correctly you can set a glass of water on the glareshield and not spill a drop...

AstroDad

I am still not happy with where the ailerons pivot inside the wing. that pivot point has a little play which I think it contributing to some flutter issues I have had. to repair it I need to remove the center spars which will be a lot easier with the wing in two halfs.

I have reinforced my tail stabilizers and ailerons where the control wire is, but that is really all I have done.

I have not had any hard landings (knock wood), anything else you think I should consider?

bruce88123

Convert to dual wing servos. Mount one in each wing several bays out from the wing center-line. There are many drawing of how to do this available. Then a direct pushrod can be connected to each elevator.

A snap roll amounts to a spin done perpendicular to the original line of flight. First the UP elevator pitches the plane up and causes the wing to stall. Then the rudder causes the rotation around the axis of the original line of flight.

Flying freak

If your gonna do snaps epoxy your wings togeather...

Red B.

A correctly performed aileron roll will produce negative g forces during the inverted part. The glass of water will not stay put unless you perform a barrel roll, which can be performed with positive g forces only.

bruce88123

Red is correct. A barrel roll is entered by first pitching the nose up slightly. It is then pulled through the roll using both aileron and elevator. It looks like you are flying AROUND a barrel while keeping the canopy facing the barrel. A large barrel roll will have the nose varying @ 45 degrees right & left and up & down from the original line of flight. Any gains/losses of altitude or heading should zero out at the end.

Bob Hoover and I believe Art Scholl have both done the "Glass of water" trick. http://www.youtube.com/watch?v=tOZEgKXJMCE

Adui

I too have the aileron play you mention. The only thing I can think of to do is the afforementioned dual aileron servo idea. The only reason I havent done that is lack of extra servos. (Got two builds in need of 5 servos each before i can even consider adding a servo to my Arrow)

In fact, I have to say the ailerons are the ONLY dissapointing item I have in my Arrow. They are just not built to fly like this thing can fly.

In any case, soon as you sort it out I do highly suggest glueing the wing halves. Yes it makes future repairs more difficult, but I would hate to hear you lost her because a wing separated in flight.

Bob Mitchell

I've seen him do the 'energy conservation" routine a number of years ago, although I thought I remembered being done in an Aerostar. It was at the Blue Angles end of season show at their home field in Pensacola. Very impressive.

AstroDad

That is an awesome idea!!!!

I wonder if I could also spit the ailerons and have quad ailerons or ailerons and flaps?

Think the ailerons would still be pleanty effictive if I convered the inside 1/3 into flaps?

Adui

Just my uneducated guess, but I would say you will probably need to add surface area to each if you do this. A half inch to an inch in width (Chordwise). I say this only because the Arrow, while very capable, does have quite narrow ailerons. Cut em down to make it have flaps and you might not have enough control surface to get the job done.

But, why would you want flaps on the Arrow anyhow? She already practically refuses to land unless she's flying at a slow crawl.

Second thought, if you use a computer radio, you could use individual channels for the dual servo set up and program flaperons. This way you ge the full aileron when you need it, and an aileron length flap when you want it.

AstroDad

True, I probably just have Ultra-stick envy. If I got the quad flaps on the arrow then I would probably give up the idea of getting an ultra stick. Seems like with a computer radio like I have it would be fun to do a lot of cool stuff that you can with quad-ailerons, like crows feet landing.

anyway assuming I forget about the quad flaps, but do the individual servos for each aileron, suppose I could save weight and space by using two micro-servos with 20 lbs of torque each to replace my current single servo with 40 lbs of torque? seems like I would still have the same total torque of about 40 lbs.

I have not seen any designs for this mod, but I assume I should add a ply on the underside of the wing joining two of the middle spars and then mount the servo in the new ply. sound about right?

WMB

My Feedback: (1)

Snap rolls are FUN. they can be quite violent also. I've been playing with them a bunch on the 4*40 lately. When the stick movement is moderated, the snap is softened. I try to do them on uplines. My kid was flying and I was showing him how to do them. He forgot the upline part and did full throttle snaps from level flight. That got my attention!
Try moving the aileron stick the opposite direction. This gets some cool effects.

I have done them for awhile now. But this year I have really been trying to see the effects of different stick movements and having fun doing it. I have a 40 Zero with 82 Saito that snaps insane. It's amazing these things hold up as well as they do.

Do them up high!, MikeB

Adui

Sounds right to me. What I was going to do (if) when I do mine was to uncover the area around the existing mount and essentially duplicate that out in the wing further.