jsfBoat

Because of the bad weather today, my CFI and I decided to do a ground lesson for my CFI. I tried to teach accelerated stalls, but sucked at it. Any one feel like giving me pointers for this one? I'm stumped.

FlyerJosh

Idle power. Lower nose. Establish accelerating descent. 10-15 knots before the yellow arc, sharply, but smoothly pull back the yoke. The plane will stall.

Repeat, but this time do it while in a 30 degree bank. Each time you can stall the aircraft well above 100 knots if accomplished correctly.

ryan1234

Not exceeding Va is a huge part of this obviously, probably want to be in the utility category...so under 100kias is more than enough for let's say a 172 Basically just set slightly lower than normal power and bank and yank until she buffets... 45 -60 degrees works...just keep that ball in place... If it's not working just keep a little power in, and pull harder during the bank

I find it's a lot easier in an aircraft with a stick(and aerbatic)...yokes seem a little akward

250 or point 65

i belive what the op was asking is how would you teach them on the ground. i think the most important point to be made about accelerated stalls is that aerodynamic stall occurs when the critical AOA is exceeded. it does not matter what airspeed you are at as long as you exceed critical AOA. i think that this concept is what i would base my ground lesson around. may also be a good time to discuss factors that effect stall speed. after a good discussion about why accelerated stall happens, then about how to perform an accelerated stall, performing the manuever would really drive home the concept. good?

Ewfflyer

A good mention is accelerated stalls can occur while maintaining altitude at a speed well above stall(1.3+ VSO) while manuevering. Using the load-factor of what a 30 degree turn, vs. a 45 and 60 degree turn in required lift to maintain that level flight, will prove that the wing can no longer provide X amount of lift, and hence the stall will occur at say 90kts+ in your typical GA trainer.

I also like the demonstration as mentioned above to set up the stall to occur during a descent, but would save that for the commercial students, and do the straight and level demo for PPL students.

My coworker and I were test flying an Aerostar and he was saying "hi" over his house, about 35-40degree's bank, and we got a buffet at 155kias!!!! Definately an Oh $h!t moment. I forget what the stall speed is, but it was definately below 90kias clean.

ryan1234

good points... I'd just like to add that the relationship of accelerated stalls to Va is very important... If I'm not mistaken Va is V-accelerate, basically can easily be described with the simple physics formula: F=MA flipped around to A=F/M... which is why Va is lower with lower weight. The accelerated stall is accelerated because mass is being accelerated, increasing G-loading until critical AoA. Providing there is not enough lift (at higher velocity) to produce structural damage (exceeding Va).

Just a side note... Va does not always protect you from structural damage... depending on the aircraft, assymetrical loading can actually put higher g-loading on certain control surfaces at lower airspeeds causing structural damage.

Der Meister

I do my accelerated stalls in a bank as well. Its more pertinent I think to show a student that way. True you can do the same thing in a dive with a prompt control input, but more than not pilots will get them selves into that situation during a turn, especially then turning from base to an over shooting final.