ravill

My Feedback: (11)

Didn't Jascat ask about TIP stalling?

Every single airplane will stall, but which ones are prone to tip stalling?

I'd say the BVM Bandit never, ever, ever, ever, ever TIP stalls!!

Raf

JohnMac

Quite right. The idea is to gently stall just as you touch down.
Regards,

John

JohnMac

Thank you sicklik for your explanation. However, you may wish to reconsider what you have said here. The whole deal to land any aircraft or model is to reach the stall point just above the runway. in the case of a model this may be 1" above the tarmac, in which case you have a greaser. If you touch down too fast (and therefore at to low an angle of attack, and hence unstalled) the aircraft is still flying. Have you ever seen a bad landing with a Kangaroo?
The hammerhead is "Technically" called a Hammerhead Stall. It is called this because at the end of the manoeuvre, the aircraft stalls! You might want to consider what the angle of attack is as the models drops out of the sky a**e first.
180 degrees - Above the stalling angle? Below the stalling angle? Hmmm!
Rav, You are quite right. The best jets to avoid tip stalling are deltas and other low aspect ratio plan forms. Delta canards are especially good. However, plan forms that have LEX's, also can have somewhat similar characteristics to canards. Washout in the wingtip and the use of flaps for landing, will all reduce the possibility off a tip stall. Finally, have the cg in a safe position ( better a little nose heavy than tail heavy).

Synthetic

My Feedback: (18)

Thank you John! I was hoping I wasn't completely crazy!

I thought when it wouldn't FLY anymore....it lands and hopefully it is very close to the ground when that takes place....

Wayne22

My Feedback: (2)

The only full size aircraft that you want to stall upon landing are small taildraggers. Even though you Cessna's stall warning horn may be blarring away, it most often is only approaching a stall condition. If you thump it in, well, then you stalled..ususally not a good thing. Bigger planes you fly them in...and use all the devices at your disposal (spoilers, chutes, reverse thrust, etc) to rapidly transfer the weight on the main gear....

Anyways...back to tip stalling.....

Not all deltas are imune.....I have Super Reaper that will tip stall..

siclick33

John,

I don't want to get in an argument. As you can see from my location I am not far from you and hope to be flying at Elvington soon. Hopefully we will be able to chat this over whilst we fly or over a beer

I don't believe that I need to reconsider. I would argue that the whole point in landing is to place the aircraft on the ground under control. If you stall 1 inch above the ground then that last inch is not under control. Not so much of a problem there but if you do it a foot off the ground then you may be in trouble. I prefer to land slightly above the stall speed so that I am always in control and thereby risk crashing (not that I can always do that)

Regarding the Hammerhead (stall) turn, the name is a misnomer. I can categorically say the during a correctly flown stall turn the aircraft is never stalled. If you get a chance to fly it in a full size aircraft you will see that any stall warnings (stall warner, buffet etc) do not occur even though you are way below the stall speed.



What has this got to do with model jets? Well as suggested by Jascat at the opening of the thread, many models do not have great stall characteristics and heavily loaded jets are notoriously bad. I have seen many approaches flown where the wings are rocking on the way down as the model is being flown too slowly (the wing rock is sometimes telling you something) with no concern from the pilot. I have seen many models stall and crash in the undershoot (fortunately not many jets).

How would you notice an approaching stall? What would you do if you find yourself in this situation on the approach? These are expensive toys and I think we owe it to ourselves to understand what they are doing in the air. As a result of this additional knowledge hopefully we can all fly better and make our investments last longer.

HarryC

My Feedback: (1)

No full size type that I have flown is stalled onto the runway, at least not intentionally. Light aircraft should be close to the stall when they touch down but not actually stall while still airborne. This is not because it is required in order to put it on the ground but to minimise stresses on the undercarriage. The plane can be landed perfectly well at higher speeds and less of a nose up attitude. Faster and heavier types eg fighters and airliners are safely above stall speed when they touch down. A stall is not required in order to put the plane on the ground, just a rate of descent.

John and siclick, you are arguing about different manouevres due to British and American terms. What we call a stall turn, the Americans call a Hammerhead. That manoeuvre is not a stalled manouevre. What we call a hammerhead is what the Americans would call the exit from a tailslide, which does involve being stalled albeit only very briefly.

Harry

siclick33

Harry C.

There is a possibilty of slight confusion but I am only aware of 2 types of Hammerhead. The stall turn and the Hammerhead stall (Humpty-Bump). Neither manoeuvres invlove a stall as far as I am aware. Maybe we should have this discussion on another forum?

NickC5FE

My Feedback: (31)

What jet wont tip stall.........Just being funny but here goes!

HarryC

My Feedback: (1)

I am told that my Avonds Starfighter will start wing rocking as it approaches the stall, I haven't had that yet but if it does my instinct will be to ease off the elevator and adjust the power. With the benefit of a long runway I approach fast and low, and then idle the power as it is making a low pass, then hold it a couple of inches above the ground and wait for the speed to bleed off and keep raising the nose. With the Sabre I have simply built up experience of what attitude it is in when it starts to feel like it is about to run away by itself and drops wingtips, so I fly it a little below that attitude.

Harry

rjbob

My Feedback: (8)

Oh, Nicky!

A turboprop (in this case, a Cessna 208) is not a jet. BTW, I was a company instructor in Caravans in western Alaska and take it from one who knows..they will tip stall.

How's your beautiful family?

Bob

NickC5FE

My Feedback: (31)

Bob, by the definitions it is a jet...........Anyways, thanks for asking, they are all doing well. How you doing?

HarryC

My Feedback: (1)

A humpty bump has nothing to do with either - it is a quarter loop, a straight vertical, a half loop over the top, a straight downline and a quarter loop back to level.
Aerobatic names are rather fluid, between countries and over time. But in Britain a hammerhead stall is generally meant for that part of a tailslide where the plane pitches rapidly from vertically up to vertically down, and thus for that second or so while it is pitching the wing will be stalled until the plane is nose down enough,

H.

Goin West

Guy's, you cant apply a blanket statement that no F-16's can tip stall. Not all F-16 models are the same and one guy's wing might be cambered diffrently than the other's. What about the Kyosho F-16? I am prety sure I seen it tip stall.... and I'm pretty sure a hammerhead is in a stall when the definition is the cessation of generated lift.

Shaun Evans

LOLOLOLOL!!!


Transubstantiation?? Isn't that a rather big word for you??

Synthetic

My Feedback: (18)

pantherflyr ,
What IS the definition of a jet?

CHAWKJIM

The Super Reaper will not tip stall . It has that large delta wing.

CHAWKJIM

the super reaper is a Mick Reeves Models kit and is very affordable . The turbine in mine is a behotec 130. and good looking with no tip stall

rcpete347

My Feedback: (251)

HI all, on my first Bobcat, i moved the CG so far back, it would wing rock on landings, ready to stall, so I knew not to go any further back.
On my second bobcat with the CG, 1/4'' behind the recommended CG, I purposely flew it around to see how slow it would fly and on final with a cross wind over the trees, it snapped and luckally, I was high enough to save it.
Lesson, you have to watch out for that cross wind.
Rcpete

Erik R

My Feedback: (32)

So many experts,with so many opinions.Truth is ,any conventional airplane will tip stall at a high enough AOA. Most canard designs will not,because the canard will stall before the wings critical AOA.If you pull enough g's any conventional airplane will tip stall.Someone made references to delta's being benign.Anyone who has flown an old school yellow A-4 will tell you that is not necessarily the case.WFO,on the step,you can pull enough g in a turn with that airplane to make it tip stall.It is purely a function of wing loading,and bank angle will increase that number exponentially.Everyone who mushed their F-16,did it wings level,or close to it.I can tell you that at 180 knots,it takes 25% more power to hold airspeed in a DC-9,with a 20 deg bank angle,than straight and level.

If you're concerned with your ability to recognize the onset of this condition,stay with the more benign designs.Go find out for yourself,and take all the opinions with a grain of salt.Good luck.

Erik

Shaun Evans

Erik,

Funny you mentioned the Yellow A-4. It's a good example of what a tip-stall looks like. That plane, when at the stall angle, would tip out pretty abruptly. With enough speed (and, by extension, G-forces) in a turn, the angle could be reached with too much elevator and high-speed tip it. That looked scary!

When I was first cutting my jet-teeth, Buck (aka Yeahbaby) was showing me the ropes on A-4's and once said, "uhh...ur pushing the high-speed departure, bro" and then I thought to myself "whatever, dude...I'm fine...." Right about that time, I did a power-dive and yanked up on it and it high-speed stalled! Craziest stall I ever saw. I looked over at Buck--who didn't say anything--he just kept his gaze upward but had that little grin going... After that, I pretty much listened to everything else he had to say about flying that plane!

When you learn where the stall angle is, it's the funnest little jet in the world.

ianober

My Feedback: (12)

I would say my responses were quite smalll for a gasbag, however the one above I think would qualify.

Call it an ad if you wish, but its just the truth. And I believe the thread topic was "What jets dont tip stall?", this is one, so please don't hate.

siclick33

Harry,

Can you please explain how an aerofoil is stalled when it is not creating lift? I think I am missing something here.

HarryC

My Feedback: (1)

If you visualise the airflow over the wing during the transition from pointing up to pointing down, bearing in mind that the plane is falling through the air and is not merely rotating on the spot, then there is a large part of the time that the AoA is way above the stall angle. For example at the point where the plane is level but falling the AoA is 90 degrees. As the nose comes down the AoA will reduce until at last it unstalls. In Britain the "hammerhead" also used to be used for a genuine stall done from an extremely steep climb, where the break away and the nose drop would be very sharp compared to a normal level flight stall.

jetjohn

As per Chalkjim,
Mick Reeves Super Reaper,it will stall,but not tip stall, but you have to be going so slow that it will fall out of the sky.
It will hover in a 5mph plus head wind.
Which when you see it hovering/staying still in flight takes some believing,then open the throttle & go vertical,allways amazes onlookers.
All the best,
John C