Full power stalls

[jcarne]

Anyone else notice when doing full power stalls that the aircraft has an absurdly large amount of pitch drop off? Was practicing the other day and the nose went from 28 degrees up to 41 degrees down once I finally got it to a fully developed stall. Sure got the attention of me and my CFI. lol Been flying a lot lately and I'm pretty well practiced up, just wanted to see if anyone else has seen such an aggressive pitch down on theirs. Don't really recall quite the nose drop during testing but that was a couple years ago now.

 

[ronrapp]

Part of this might be technique. The pitch rate as you approach the stall can affect the behavior after reaching the critical AOA. I'm sure propeller type, CG location, and many other factors are at play as well.

I've done stall series in all the two seat RVs except the 14, and they've varied based on the aircraft configuration and pilot technique. In some airplanes (typically ones with a CS prop, 180-200 hp engine, favorable CG etc), where the stall is approached gradually, the wing could be flying again by the time the pitch attitude reaches the horizon. In other airplanes, not so much.

In terms of pilot technique, there's going to be a big difference in stall recovery depending on what you're doing with the elevator. Are you holding aft stick into the stall at all? Releasing pressure as soon as it breaks? Pushing the nose down to lower the AOA aggressively?

Lots of variables at play. So your numbers don't really surprise me too much. But you probably know your particular airplane better than anyone, so if you feel something has recently change in the way it handles, you're probably right.

--Ron

 

[Dan 57]

Did quite a few with my -6.9 during the flight testing for a higher gross, at MTOM... yes, quite some pitch up, and pitch down. But nothing crazy if one is used to fly aeros
It was all recorded for data analysis, but I'm too lazy to dig out the files which are somewhere nested in some obscure cave of my hard drive

 

[Taltruda]

Never measured it, but that sounds normal.. holding the full stall with full power is probably going to result in a spin, you should practice recovering at the buffeting, as if it was a stall on takeoff/goaround and there isn’t altitude below you to lose. You get the buffet, then quickly lower the AOA to about zero degrees of pitch, leaving the full power in, and the plane will fly out of the stall without losing any altitude (or very little) however, if it goes into a spin from it, the standard spin recovery (PARE) works well to recover.

 

[Desert Rat]

I've only done a couple of stalls in my one and only RV7 ride a few years ago, and don't really remember anything like that, but I might have just forgotten. How experienced is your CFI? Is he largely coming from Cessna's and Pipers?

Going into CFI mode for a minute. Apologies if this is old news;

Typically the higher you get the nose the more dramatic the recovery. i.e. if it's super nose high it has to describe more of an arc to find it's happy place below the critical angle of attack.

The slower you go into the entry, the less inertia to bleed off and the lower the nose at the stall entry=less nose low at recovery. A 1 kt per second airspeed decay is what the King Schools Cessna Course Tracking pt 141 curriculum recommends. I realize this isn't a Cessna, but that gives you some idea of what I mean by rushing the entry.

Likewise, doing stalls at full power in a light or overpowered airplane can get the nose so high that you get the same result as rushing the entry.

I wholeheartedly support the idea of doing power on stalls at full power because, hey, we're simulating a takeoff right? But just in case you don't know- The ACS standard for the PPL specifies that during check rides, the power setting for power on stalls should be "no less that 65%" They don't have a one size fits all full power requirement largely for the reasons above.

Again, apologies if this is all old news.

 

[lr172]

I was doing power on stalls with my son in the 6, prepping for his checkride. Nose was going insanely high and still didn't stall. Called DPE and asked if that was really what he was looking for. He said slow down to about 10 over stall speed, THEN apply full power and nose up into the stall. When we tried this, the stall occurred at a much lower angle. DPE said this procedure simulates a take off stall and what the FAA is looking to be sure students can deal with.

Not sure what your intentions are with these maneuvers, but thought it may help.

Larry

 

[Untainted123]

Larry,
I agree to slowing down first. In some RV's, going into a power on stall from near cruise speed, you might be able to complete a loop instead of ever stalling

I was taught, and teach, that the best simulation is to slow down to very near rotation speed, then initiate a power on stall sequence. This to me is also simulating better what the risks are on a takeoff or balked landing to students and the more likely scenario they will find themselves in normal day to day flying.

 

[agent4573]

Wife just went through this in the RV7 for her commercial as well. Get into slow flight first and settle out around 65 knots. Then apply around 70% and pull the nose up. She settled on 70% power after realized that she was routinely exceeding the 30 degree maximum nose up allowable per the ACS. If you start from any faster, you're doing a zoom climb instead of a stall simulation and will go through a few thousand feet before it slows down. She also did it with flaps in to be more draggy, just make sure you don't exceed flap speeds.

What she and her instructor found interesting was that while it was very hard to get into a fully developed power on stall, it was very easy to encounter a secondary stall during recovery, so make sure you find that limit as well.

 

[jcarne]

Ya I have been practicing for my commercial checkride coming up and this is when we really noticed it. It is pretty dang obvious when she wants to stall with full power and nose high but the DPE could ask for full stall. I will probably have the conversation with him that it will likely be fairly aggressive and maybe more than he wants. haha

I usually slow to 70 (vx) and then apply full power (around 70-75%). Maybe I'll slow it down a bit more first. I have to get the nose to almost 30 degrees in order for it to stall in a reasonable amount of time. Wonder if I'm just being too aggressive with the maneuver and that's why I'm getting such a large break. I was probably a bit more timid in the past. Either way if he wants to experience that amount of pitch change I'm cool with it. Just wondered if everyone else get's similar results as there isn't much chatter on full power stalls on the forums.

I guess in the end it's about the recovery and I have no issues with that, even if it's 41 degrees downhill. As long as it's not low to the ground... lol

 

[wcalvert]

Jereme

I went out today to explore your issue a bit... nice cold day at 4k'. Slowed to about 55 kias with half flap, then started adding in power as the nose came up and the speed dropped, level flight. Took about 15 or 20 seconds and I was almost 40 degree nose up at less than 40 kias (who knows what kind of instrument error there was ?! the plane shouldn't fly that slow).

When the stall broke in heavy buffet I eased the stick, kept the aileron centered and recovered to level flight with no altitude loss. Balanced flight (with rudder only) during the entry and recovery. No wing drop.

My guess is that you're adding some aileron causing one wing to stall and the nose to slice, making the nose drop rapidly.

I would say this is an exercise in aircraft control more than a actual stall scenario. It does demonstrate the importance of rudder only inputs at low speeds and maintaining balanced flight.

Playing around at the edge of the envelope is always useful, the more you're comfortable there the safer you'll be.

Good luck on the exam! Cheers