Need help with some commercial maneuvers.

[pfitmx15]

FYI: I can "glide" the cherokee in all day, the Arrow is a different animal entirely.

Agreed. The best power off 180's I've done so far I have had to make an immediate turn to base when the power is pulled.

You sure about this? I see it done usually a few times a week. I am going up with a commercial student today, would you like me to video tape it for you??

I would definately like to see this if you dont mind. And i'm not saying that it can't happen either. Just would be interesting to see how someone else would do it.

Wow guys I love this place. This debate going on has a ton of great information. I especially liked your explanation Steve C. That could save a students life explaining the steeper turns in the pattern like you described.

matt

 

[MikeD]

Have you had to fly a true flameout approach in your career? I'd love to see you in the real situation; unfamiliar field, winds not to favor, pattern position not optimal, trees or powerlines at the approach end of the field/landing point, visibility not great, stressed out, on fire, and/or any of the myriad number of monkey wrenches that can be thrown at you; and we'll see how pretty and parameter-specific your pattern is.

.

Shdw, you have failed to answer this.

 

[t-cart]

There is a lot of difference in reading something out of a book and dealing with a real life emergency. Sometimes you have to read between the lines.

 

[richarms]

... Have you had to fly a true flameout approach in your career? I'd love to see you in the real situation; unfamiliar field, winds not to favor, pattern position not optimal, trees or powerlines at the approach end of the field/landing point, visibility not great, stressed out, on fire, and/or any of the myriad number of monkey wrenches that can be thrown at you; and we'll see how pretty and parameter-specific your pattern is.

Your inflexibility isn't going to serve you well someday, partner. It may even kill you.

Take that to the bank.

Exactly. I teach the maneuvers and put them to practical use. With my commercial student reaching the end of training last weekend, I pulled the power on our short X-C over a small airport. He steep spiraled down, rolled out in midfield downwind and landed (with flaps & slip). Not only a great confidence builder, but used the tools to effect the desired outcome. Simply did what was necessary and touched down on the called spot. No hesitation at a strange field without practice to short runway and obstacles.

 

[JrsyGuy]

It seems like some of you guys are jumping on shdw for having specific parameters that he adheres to and then go on to say that they always do it this other, different, way.

I really disagree with most of statements so far on here regarding this procedure as you need to take pieces from all your playbooks but i am more inclined to stick with shdw here. Since it is not necessary to bank more than 30 degrees the majority of the time in the pattern whether power off or not why would you teach someone to go against the grain in an emergency. You shouldn't need to alter your methods too much in an emergency. With that said, there will always be the need to 'fly the airplane' and it's your job to get down safely and that may require steeper banks and slips and anything else you have in your bag of tricks. That's why you should teach multiple methods but I'd still try and keep it as simple as possible and not change techniques drastically for no power landings.

 

[MikeD]

It seems like some of you guys are jumping on shdw for having specific parameters that he adheres to and then go on to say that they always do it this other, different, way.

I really disagree with most of statements so far on here regarding this procedure as you need to take pieces from all your playbooks but i am more inclined to stick with shdw here. Since it is not necessary to bank more than 30 degrees the majority of the time in the pattern whether power off or not why would you teach someone to go against the grain in an emergency. You shouldn't need to alter your methods too much in an emergency. With that said, there will always be the need to 'fly the airplane' and it's your job to get down safely and that may require steeper banks and slips and anything else you have in your bag of tricks. That's why you should teach multiple methods but I'd still try and keep it as simple as possible and not change techniques drastically for no power landings.

Yes. You just requoted this:

Now I can see doing your best to plan/perform a flameout approach where you don't have to use any of the corrective maneuvers mentioned; that's all well and good. BUT, knowing when a situation will require them, and how to safely incorporate them into correcting a situation you could easily find yourself in (high/low/fast/slow, etc) is equally as important and completely correct.

 

[JrsyGuy]

Yes. You just requoted this:

Mine sounds better

 

[MikeD]

Mine sounds better

LOL.....ok, you got me there!

 

[shdw]

Thank you Jrsyguy us Jersey folk must stick together!!!

To restate yet again I never said these maneuvers shouldn't be known and you shouldn't be able to use them. I said with proper planning you shouldn't have to especially in an emergency when there are many other factors involved.

As for all this turn arguments time to settle this once and for all math doesn't lie.

For the arrow 79 knots
Radius - 961 feet
Diameter - 0.3 nautical miles
180 degree turn time - 22.6 seconds
If your telling me that you fall 1000 feet in 22.6 seconds man I would love to know who maintains your aircraft!

Now for the folks about to say oooo what about wind here are some numbers for higher speeds:

For 100 knots:
Radius - 1540.8 feet
Diameter - 0.5 NM
180 degree turn time - 28.6 sec

For 120 knots:
Radius - 2218.1 feet
Diameter - 0.7 NM
180 degree turn time - 34.4 sec

For 140 knots:
Radius - 3020.0 feet
Diameter - 1 NM
180 degree turn time - 40.1 sec

For 200 knots:
Radius - 6163.3 feet
Diameter - 2 NM
180 degree turn time - 57.2 sec

All of this can be found at http://www.csgnetwork.com/aircraftturninfocalc.html

Look at the time for your 180 degree turns at 30 degrees even for 200 knots as long as your best glide yields less then 1000 feet per minute you can easily perform the turn to land safely as long as you judge your diameter properly. Sure some higher performance aircrafts will be over 1000 feet a minute especially twins with dual engine outs. But the arrow is right at 1000 feet a minute at best glide and it is a horrible gliding aircraft.

Let me repeat so I don't get bashed here, these are not absolutes they don't' take into account lift and sink. However, they do show that for any plane 140 knots or less best glide you will have approximately 20 seconds to spare after doing a 30 degree bank 180 degree turn if altitude loss is at or below 1000 feet a minute at glide.

Sorry for all the math got tired of this arbitrary number BS going on.

 

[JrsyGuy]

FACT: it is not possible to perform a 180 in the Arrow from pattern altitude (1000` AGL and 1000`out) without exceeding 30 degrees of bank. You will overshoot base to final EVERY TIME. As far as the slip, I can correct for being high, I can't correct for being short.

I'm not sure why you are so strict on this 1000' out? If you need to make a 30+ degree turn to make final then why not fly a wider downwind and make your bank less?

Maybe I'm missing something

Thank you Jrsyguy us Jersey folk must stick together!!!

:rawk:

 

[shdw]

Shdw, you have failed to answer this.

No I havn't had to perform a power out approach yet unless you count the glider with a 14/1 or 15/1 glide ratio (Grob 109B) 16/1 book value but not with the greased up bottom it had.

 

[tgrayson]

after coming back down to altitude the speed is not back to normal

If you consistently end up high or fast, reduce power at the beginning of the maneuver. If you are consistently low or slow, increase power at the beginning of the maneuver.

Second I seem to have a little difficulty with the power off 180.

I love the Arrow for this maneuver. If this is the Hershey bar Arrow, you need to 1) flight a tight, tight pattern and 2) keep a decent speed up in the down wind (e.g., 120 mph), and 3) turn immediately after cutting power.

Note that your best glide airspeed with the gear down is slower than published best glide. I also make sure that students are comfortable performing a slipping turn to final and keeping the slip all the way to touchdown if necessary.

Our local examiners frown on raising the flaps to extend the glide, but it does work.

 

[Douglas]

Our local examiners frown on raising the flaps to extend the glide, but it does work.

raising?
----
if you meant lowering, the odd thing is that our local examiners talked me into adding flaps to extend glide.

 

[tgrayson]

if you meant lowering, the odd thing is that our local examiners talked me into adding flaps to extend glide.

No, I meant raising. Lowering flaps increases drag, and drag is the enemy of glide range. If lowering flaps reduced drag, we'd leave them down all the time.

 

[shdw]

No, I meant raising. Lowering flaps increases drag, and drag is the enemy of glide range. If lowering flaps reduced drag, we'd leave them down all the time.

No, he means lowering. But I think you guys are at two different approach points. Raising them while still high up will give you reduced drag and better glide. Dropping the last notch in while in ground effect can give you an extra 50-100 feet in the Arrow. So your both right its just a timing issue

) keep a decent speed up in the down wind (e.g., 120 mph),

Why? Best glide = L/D max = minimum drag = furthest distance covered. If anything slow down more since best glide is lower as weight goes down and here is how to find that.

square root (actual weight/max gross weight) * best glide speed
Example
Max gross = 2750
Approx weight with 2 pax and half fuel = 2300 (complete guess I am too lazy to do this for an example )
square root (2300/2750) * 79 = 72.2
Use this formula on the ground if you want but in the air the formula below is better.

Another way to do this which is more practical and easier to do in your head (who can do square roots in their head?) is this:
(1-((max gross - actual)/max gross)/2)) * best glide
It sounds more complicated but all you are taking is the difference 2750-2300 = 450 and dividing that into 2750 to get a percentage. In this case .16 or 16 percent then divide that by 2 gives you an 8 percent reduction in speed. The 1-.8 is just for the calculators purpose which is .92 * 79 = 72.7 which isn't exact but a good rough guesstimate that you could perform in your head if time permitted and you were over mountains trying to get every bit out of your aircraft.

Another speed not commonly discussed in minimum sink which occurs 3-5 knots below best glide and corresponds to minimum power required on the Pa/Pr curve. This speed will give you the longest time in the air (mostly used by glider pilots) and with a good tailwind would give you a greater distance than best glide simply by giving you more time. This is also the better speed to fly in downwind for the reason discussed in the previous sentence. In a headwind is when it can sometimes be better to alter glide speed to slightly faster but the differences are negligible.

your best glide airspeed with the gear down is slower than published best glide.

I looked through the book and was unable to figure out where you found this or how you know this. I don't know if it is right or wrong so I won't argue for once!!! But can you please elaborate because I would like to understand this. Thanks

 

[tgrayson]

Dropping the last notch in while in ground effect can give you an extra 50-100 feet in the Arrow.

No doubt, but pulling back just a little bit more on the yoke accomplishes the same thing and is less distracting. If you had the yoke full back already, the last notch would be an option. but I suspect the attraction behind the flap technique is the novelty of it.

I'd bet that focusing on a nice, smooth flare to a full-stall touchdown is more conducive to a longer touchdown than fretting about the flap lever.

 

[shdw]

No doubt, but pulling back just a little bit more on the yoke accomplishes the same thing and is less distracting. If you had the yoke full back already, the last notch would be an option. but I suspect the attraction behind the flap technique is the novelty of it.

Yes it is assuming you have nothing left but I agree that mostly unecessary and like you said distracting. I for one don't recommend it but it can be done.

 

[tgrayson]

related question: does a trimmed airplane try to hold an airspeed or an AOA?

AoA. The airspeed will become whatever is necessary to ensure that the vertical component of lift = weight.

If you roll into an 60 degree banked turn, and apply no back pressure, the airplane will accelerate to a velocity 41% higher than wings level airspeed. As the airspeed increases, load factor will increase towards 2.0. To prevent that, you'd have to keep lowering the AoA. This is sort like a Ponzi scheme.

How do they teach you to recover? To avoid paying the load factor piper, I'd say you'd have to roll out while simultaneously lowering the AoA to avoid a big load factor increase.

 

[shdw]

I'd say you'd have to roll out while simultaneously lowering the AoA to avoid a big load factor increase.

This is also a huge factor because it increases roll rate which is something many pilots don't know or at least don't think about/realize. Speak with an aerobatic man about this they can tell you all about it. But /agree that is a perfect recovery.

 

[tgrayson]

Best glide = L/D max = minimum drag = furthest distance covered.

I was referring to when you were still carrying power. Gear down midfield, keep your speed up until abeam the touchdown point, then chop power. The faster you are at that point, the more airspeed you have to convert into altitude.

I looked through the book and was unable to figure out where you found this or how you know this. I don't know if it is right or wrong so I won't argue for once!!!

Easy. Since you seem technically minded, draw the induced drag curve and parasite drag curve. The speed of best glide is at the intersection. Now raise the parasite drag curve due to gear extension and see what happens to the best glide airspeed.