Over-square Cruise Power Settings and Slipping with Flaps Husky A-1

belloypilot

belloypilot

Active Member
Where I tend to use slipping on final most often is when I want to increase my rate of descent without giving up any more air speed in anticipation of a go-around. Checking out a potential landing spot in tight river valley, for example. I find being able to descend at > 1000 fpm while keeping the speed up around 70 to be useful. When I slow down for the actual landing the decent rate and lower ground speed is usually such that I seldom need to slip, even to get into those tight spots. Lots more experienced Husky drivers on this forum than I - that's just how I use that particular arrow in the quiver.

Mike
 
M

MTV

Active Member
A couple of observations and a point or two:

I once contacted Lycoming Tech Support reference the notion of running an O-360 "over square". I explained what I was flying, and why I wanted to operate the engine oversquare: More mpg. The Tech gent said he'd look into it, and get back to me, via email. A few days later, he sent me an email, which said essentially, operating an O-360 up to 9 inches "oversquare" won't hurt anything. Personally, I've never been able to get even close to that far oversquare.
As to the basic notion of running "oversquare" being bad for your engine....there are many engines that routinely and regularly operate oversquare. Wive's tale.

Slips with flaps deployed in Husky: Won't hurt anything, but in my experience, if you're having to use slips to get down, you may be flying way too fast. Yes, you can run the plane up to the top of the white arc, but now you'll still have to dissipate all that speed. Frankly, most Husky pilots (and Cub pilots for that matter) fly approaches waaaaay too fast. Slow the plane down, keep the prop at fine pitch....if the shit hits the fan, push up power, and leave. These planes are magnificent climbers.

Border Patrol accidents: I have discussed these accidents with CBP personnel with direct knowledge of the accidents. These accidents had NOTHING to do with merely circling at low level. The maneuver that precipitated these accidents is not something any of you are likely to try....trust me. Mark Heiner and his cousin Verdean Heiner experimented with Huskys at the factory in an attempt to duplicate these accidents. They were eventually successful, by using two Huskys, one to generate max power during a pitch up, just ahead and above the trail aircraft, which pitched hard over, once.

Repeated circling is a uniquely bad idea, in any case, though. And I recommend against it. As one who's done so a great deal, I became a fan of a 270 degree turn followed by another 270 degree turn for repeated passes over a subject at low level.

Repeated circling has killed a number of pilots and their passengers, including several good friends. I firmly believe it is a wake vortex related phenomenon, NOT a tail stall. I don't have scientific proof, but I've been able to duplicate the famous "Moose stall" once in about 200 attempts.

Be careful out there,

MTV
 
J

johnaz

Active Member
MTV said:
A couple of observations and a point or two:

I once contacted Lycoming Tech Support reference the notion of running an O-360 "over square". I explained what I was flying, and why I wanted to operate the engine oversquare: More mpg. The Tech gent said he'd look into it, and get back to me, via email. A few days later, he sent me an email, which said essentially, operating an O-360 up to 9 inches "oversquare" won't hurt anything. Personally, I've never been able to get even close to that far oversquare.
As to the basic notion of running "oversquare" being bad for your engine....there are many engines that routinely and regularly operate oversquare. Wive's tale.

Slips with flaps deployed in Husky: Won't hurt anything, but in my experience, if you're having to use slips to get down, you may be flying way too fast. Yes, you can run the plane up to the top of the white arc, but now you'll still have to dissipate all that speed. Frankly, most Husky pilots (and Cub pilots for that matter) fly approaches waaaaay too fast. Slow the plane down, keep the prop at fine pitch....if the shit hits the fan, push up power, and leave. These planes are magnificent climbers.

Border Patrol accidents: I have discussed these accidents with CBP personnel with direct knowledge of the accidents. These accidents had NOTHING to do with merely circling at low level. The maneuver that precipitated these accidents is not something any of you are likely to try....trust me. Mark Heiner and his cousin Verdean Heiner experimented with Huskys at the factory in an attempt to duplicate these accidents. They were eventually successful, by using two Huskys, one to generate max power during a pitch up, just ahead and above the trail aircraft, which pitched hard over, once.

Repeated circling is a uniquely bad idea, in any case, though. And I recommend against it. As one who's done so a great deal, I became a fan of a 270 degree turn followed by another 270 degree turn for repeated passes over a subject at low level.

Repeated circling has killed a number of pilots and their passengers, including several good friends. I firmly believe it is a wake vortex related phenomenon, NOT a tail stall. I don't have scientific proof, but I've been able to duplicate the famous "Moose stall" once in about 200 attempts.

Be careful out there,

MTV
Click to expand...
Mike,
My thoughts on most landing too fast in the Husky. All too common.
John
 
tbienz

tbienz

Well-Known Member
For me the slip has been useful when trying to land on a meadow/flat spot at the very beginning of a steep slope while hunting or exploring and just doing max performance landing trials in odd places (when you have a strong up-slope wind precluding approach toward the mountain, and which also makes descending into the ridge lift difficult). There are plenty of mountain slopes I’ve encountered where idle power, 30deg flaps and fine pitch will not deliver you to the bottom of the incline at sufficiently slow speed to land in the space available. I might be wrong about how it works, but to me it seems the slip allows the plane to drop more quickly without picking up speed so you can hold the speed at 55-60 while coming down the side of a mountain. I don’t use it real often, but it seems to work well in this plane and has utility.
 
Gust Kalatzes

Gust Kalatzes

Active Member
It took a long time to quit approaching too fast and as a result I got very good at slips and using the brakes! Both were less threatening than coming in to slow at the time. The slip was an easy and very effective way to correct the approach to the point. The cure was going up at altitude practicing flying around and simulating approaches real slow with the stall warning on a few hundred times...helped get a good feel for the plane.

On occasion now I use the slip to fix a screw up and deliberately for similar reasons Thomas describes. I view the slip, being able to get on the brakes hard without nosing over or steering the plane down a narrow dirt road as just tools in your tool bag.

The slip will get you 1,800 fpm easy for 6,000 ft when your wife says it’s an emergency!:)
 
Chris McClure

Chris McClure

Member
Alex McCulloch said:
I've been a lurker for a while on here, thanks for reading my novel in advance. I've had my Husky for a few months and about 50 hours now and I thought I'd post up with two topics I've been curious about. I'd love to hear your opinions / impressions, especially the old-school heads on here with early wing experience.

Background

Airplane:
1995 Husky A-1 (old wing, old flaps)
180-HP O-360
Hartzel Metal Blade Prop 80"
Relatively Stock Example
Thomas's SGSs are the only real mod.
26" Goodyear Tires (23" in actual diameter)
29" ABWs on extra wheels I haven't mounted yet.

Pilot:
16,000 TT (ATP, CFI, CFII, MEI, CSEL) in a wide variety of aircraft types. 600hrs hang glider time not included (and as many off-airport landings).
200 Tailwheel Time, split evenly between STOL type aircraft (Piper J-3, PA-12, Husky A-1) and higher-performance experimentals (Mustang II, RVs, Thorpe T-18).
I am certainly not the ace of the base, but I'm a competent tailwheel pilot.
My attitude is one of humility; I'm keen on learning, improving and benefiting from those with more or less experience than myself.

My mission is a mix of cross-country operations and some back country stuff, virtually all of it in the high density altitudes of Colorado. I've flown the Husky through MT, ID, UT, and CO landing at medium-difficulty backcountry airports and other spots along the way.

Over-Square Cruise Power Settings

I've researched the posts on here about cruise power settings and running over-square seems to be the consensus. With the exception of a turbocharged platform, in the light training environment, I was always taught and have taught my students to keep your power settings under square to minimize strain on the engine. The consensus on here for the Husky is that going slightly over square is more efficient and keeps the engine better under load on descent. Experimenting with my own airplane, I came up with these numbers.

Conditions:
OAT: 60 degrees
Altitude: 6000'
Full Tanks
2 Passengers
At Max Gross Weight: 1800lbs (I'm an early A-1 without the 90lb mod).

Under Square:
RPM: 2350
MP: 20”
FF: 6 gph
IAS: 95 mph
CHT: low 300s

Over Square:
RPM: 1900
MP 20”
FF: 5 gph
IAS: 90 mph
CHT: low 300s

I've noticed a quieter ride at 1,900 / 20" than 2,350 / 20" but also more vibration (I could probably have the prop dynamically balanced for either power setting). I haven't pushed much further over square than 1900 / 20". In the mountains, especially if it's sporty, I'll cruise at 2,350 / 20" because the Husky feels like it has more energy if I need to react quickly to lift / sink or make a rapid course correction. In the flats, or a low-threat environment I have been preferring 1,900 / 20" for the fuel economy and noise.

What over-square cruise settings do you guys run?
And how far over-square are you comfortable with for max continuous cruise?
In the long term, is this bad for the engine / prop. What are the possible implications and things to look for?
I think I read in my engine book that there is a limitation of 1,850 RPM being the minimum continuous RPM.
Is running over-square unique to the Husky, since it is a relatively over-powered platform, so perhaps it isn't straining the engine / prop, like in a Cessna 172RG for example?

Slipping with Full Flaps

I couldn't find a limitation with about slipping with flaps. As a rule I have always avoided doing a slip with full flaps in any airplane due to the increased aerodynamic load on the flap and potential for elevator blanketing. Having flown a Husky A-1B with the new wing, MT Carbon prop, and 31" ABWs, the difference in descent rates is night and day between that and my A-1. I'm actually quite impressed at how well my early Husky glides even at idle power, full flaps and 26" Goodyears. I once wave soared it (clean, of course) on the lee-side of the Front Range at 15" of power (so I wouldn't shock cool the engine) from 11,500 to 14,000--granted the wave was nice that day. In order to fly a proper "back country" or relatively tight pattern, I've got slip it to get down and often quite aggressively (which is fun). Initially, slipping full flaps at 60-65 mph seems more productive than hanging it deep on the back side of the power curve at 50ish mph to get down. Depending on the scenario, I'll transition to that configuration prior to touch down. I have no problem widening out and flying an normal pattern, but I prefer to err on the tighter side.

Do you early wing Husky guys slip with full flaps?
I experimented slipping with full flaps high up early on, and felt no aerodynamic buffeting other than on the flap itself, or blanketing of the elevator. Is that something to worry about (I remember the Border Patrol accidents)?
I'll often incorporate my slip into a continuous downwind, base and final turn (while being extremely cognizant of my AOA due to the stall / spin threat) if the situation warrants it, which could increase the aerodynamic load on the down-wing flap vs a non-turning slip. Thoughts?
Are there areas I should inspect more frequently due to slipping with full flaps?

Thanks for your experience and opinions in advance!
Click to expand...
I have an old wing A1-B (2004) and have not had any problems slipping with full flaps or any setting below that. That said, be sure to practice at altitude before trying it on short final! Tail stalls can happen with slipping with full flaps in certain aircraft - I tow gliders with a C-150-160 that has 40 deg of flaps and at altitude after dropping off a glider, I will sometimes slip with full flaps to avoid shock cooling the engine, and when the tail stalls I pull the nose up and when it recovers, I do it again... When the tail stalls in a Cessna, the recovery is opposite from a wing stall - I really haven't had the tail stall in my Husky. It may be the difference between the Cessna 40 deg flaps and the Husky 30+ deg flaps?
 
belloypilot

belloypilot

Active Member
Anyone ever stalled a Husky in a slip? Anyone tested the limits of how slow you can go without undue excitement?
 
Chris McClure

Chris McClure

Member
I have never had any problem slipping in the Husky with full flaps. I use both if I need to lose a lot of altitude faster than just using flaps. I have often slipped right down to flare with no problems. I almost always use full flaps on landing and takeoff, except with a stiff crosswind landing, then I use one or two notches and a bit of extra speed. So far so good.
 
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