[flytoboat]

Perfect example: I live 4 miles west of the massive Edwards AFB complex. coming back from the east on the weekends, I can often fly through (over) but the altitude restriction is 6,000 feet minimum. So here I am at 6,000+ feet, with my destination airport essentially lost under the nose 3500 feet below. If I cut across Edwards to save time, but have to circle for 10 minutes on the other side, what is the use?

Michael,
The example might have ben more beneficial to understand your original question/problem before post #49. I fully agree with Ironflight though, that the responses people have graciously provided here have pretty much answered the mail. For what it's worth, I saw an RV10 at Oshkosh with speed brakes installed. The owner sells the speed brake mods and gave me his card. I'll look tonight to see if I still have it and will provide the info here.

 

[Toobuilder]

Don,

The example I provided is just one of many similar scenarios that I deal with; I guess I expected others to relate better than they did. And yes, there have been many good examples of how to deal with an approach to the airport BUT they are all "adaptations" to fit a slippery airplane to a (sometimes) impossible profile. For example, I doubt anyone wants to circle for any length of time after 2-3 hours in cruise, do an overhead, "G it up", slip, chop the throttle, etc - these maneuvers are all done to dissipate excess energy, not for "fun".

Since we're not doing a cost/benefit analysis at this point, and I'm a long way from cutting metal, it does not hurt to have a little theoretical discussion about capabilities and energy management, does it? So perhaps we can move beyond the mutual frustration and just look at it with an open mind, because when I say "speedbrakes" and someone else counters with "circle for a while", we're both talking about excess energy, right?

 

[Ron Lee]

Maybe it would be helpful if others with CS props specify their descent airspeed and descent rate (FPM) (possibly power setting as well). No doubt they can do better than I can with a fixed pitch prop. I am sometimes RPM limited following RVs with CS props.

 

[pgroell]

Other options

I'm not flying my RV yet, but flying heavy jets that are sometimes slippery too (even with speedbrakes).
One option when coming in high, if it's feasible, is to reduce the speed while high and then either use a flaps setting (even landing flaps) to get the steepest angle or just trade altitude for speed.
I have no idea how many feet you can loose by accelerating from say 80kts to 180kts in a RV.
I have no idea which method would work better in a RV.
Somebody got some figures?

 

[nucleus]

Some Flight Profiles are Not as Safe

If you are low and slow miles away from the pattern that is not as safe as being higher and/or faster, fewer options with a loss of power.

On one route I fly on a regular basis I am 4-6 thousand feet above the pattern and I don't clear the mountain until 8 miles out, which is interesting because I can't even talk to the tower until I clear that mountain, it blocks the signal.

I try to manage my descent so that I don't reach pattern altitude until I am actually entering the pattern. The green arc on the GRT is handy for this.

Hans

 

[Toobuilder]

...Fact is that sometimes I have to take a longer routing due to restricted areas. You may have to modify your approach (last part of en route flight), accept a 2-4 minute longer flight than ideal, or add speed brakes which may cut that minimal "delay" in half...

Not to be a smartass, but sometimes I have to take a longer route due to driving a car, rather than flying. However, flying adds a capability which the car lacks, and similarly, some aircraft have capability than others lack. If we fly for transportation, then it is "more capability" (translated to "less time enroute") that we seek. I guess the question of the day is whether a high drag device adds "any" capability to a RV... It certainly would not be needed on my Hiperbipe (itself, a "high drag device" ) Considering all the tactics we use to manage energy, it is beginning to sound like an overwhelming "yes" for the RV. ...A high drag device would be useful to some extent.

Practical? ..that's a whole different debate.

 

[Toobuilder]

I'm not flying my RV yet, but flying heavy jets that are sometimes slippery too (even with speedbrakes).
One option when coming in high, if it's feasible, is to reduce the speed while high and then either use a flaps setting (even landing flaps) to get the steepest angle or just trade altitude for speed...

With turbine aircraft you do not have the limitations on power management that exist with piston aircraft (real or imagined).

With a light piston transport aircraft you have conflicting requirements.

1. go fast
2. keep the power (temperature) "up"
3. get down

These often bump up against limits in speed, engine temperature and angle (not rate) of descent.

 

[Dmadd]

SBD Dauntless

Pop says the SBD he flew a few wars back had one heck of a set of speed/dive brakes on it. Wonder if I could fit them to my four... ;-)
That could be an unfair advantage in a flower bombing contest though... <BG>

DM

 

[Kevin Horton]

If you have a constant speed prop it is hard to conceive of a circumstance where speed brakes would be required. Even if you have a fixed pitch prop there are very few circumstances where speed brakes would be useful. If you have some particular situation that drives a need for more deceleration capability than you would have with a fixed pitch prop, you have the choice of installing speed brakes, or a constant speed prop. Given that a constant speed prop offers significant performance advantages in take-off and climb, and significant noise advantages in cruise, I'd take it over speed brakes any day.

But, it's your aircraft. Do whatever floats your boat.

 

[L.Adamson]

4000' to loose

We call this the Skypark approach. You duck under KSLC Class B airspace at 9000' msl as you cross a ridge line east of the airport. At that point, you have to descend at approx. 2000 fpm. to the airport pattern height of 5100'. At the base of the mountain, you only fly a mile or so, before entering a 45 to downwind for Runway 34. It's quite a bit steeper looking, than the pics might suggest!

With a C/S prop, we can easily do this. And a C/S prop sure helps for doing the reverse (climb up the canyon)! With a C/S, we can even loose airspeed on that 2000 fpm decent. This won't work with a RV & F/P, no matter how practiced you think you are. It's just impossible. Your only option at the bottom with an F/P is to turn right, and fly a few miles in a tight corridor between Class B and the mountains to loose airspeed, before a 180 back to the airport.

URL=http://img90.imageshack.us/i/dsc02914red.jpg/]

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L.Adamson --- RV6A

 

[jtrusso]

We call this the Skypark approach. You duck under KSLC Class B airspace at 9000' msl as you cross a ridge line east of the airport. At that point, you have to descend at approx. 2000 fpm. to the airport pattern height of 5100'. At the base of the mountain, you only fly a mile or so, before entering a 45 to downwind for Runway 34. It's quite a bit steeper looking, than the pics might suggest!

L.Adamson --- RV6A

Wow, that is impressive. What's your AGL height above those trees?

 

[Ron Lee]

I can do it L. Adamson

Special technique that is proprietary.

Is that Skypark in Bountiful (BTF) ?

Looks like fun. I have not done anything like it here in Colorado. Creede is a nice approach. Perhaps going over the mountains to Telluride but even that would be different.

Kidding about being able to do it. I would most likely over rev the engine trying.

 

[fehdxl]

FWIW

I have the G530 set to guide me on a 500' fpm descent to a point 1000' AGL 4nm from the airport. When it says it's time to descend, power at about 21-22" and top of the green on the airspeed from cruise altitude until that point. Then let the airspeed slow and pull the power slowly to 15" where I then use gear and flaps to descend to the runway. Seems to work okay in the Bonanza anyway--no speedbrakes. -Jim

 

[L.Adamson]

Is that Skypark in Bountiful (BTF) ?

yes

L.Adamson

 

[cyberpilot10]

Still building the Emp.

But after reading this thread I am going to install Speed Brakes, Spoilers and a C/S Prop on my RV8. I might even cut a F/P prop in half, and tie 4,000 feet of cable to it and carry it in the rear seat just in case I need an anchor. OR I just might get some transition training and learn how to fly and manage the aircraft I am building......

Rich

 

[L.Adamson]

But after reading this thread I am going to install Speed Brakes, Spoilers and a C/S Prop on my RV8. I might even cut a F/P prop in half, and tie 4,000 feet of cable to it and carry it in the rear seat just in case I need an anchor. OR I just might get some transition training and learn how to fly and manage the aircraft I am building......

Before you get to that point of building; you just have to decide on what limitations and budget you want to live with. No matter what anyone say's, an F/P prop is a limitation compared to a C/S; unless it's an all out speed war with a light weight super cruise F/P that would "stink" for takeoff performance.

Yes, it all comes down to "management" within the limitations. A friend of ours owns a nice Super Cub with large tundra tires. As we head off on our Sunday 140 mile brunch...................she simply leaves an hour before we do. She manages to get there..........with a limitation of speed. It's the same with a F/P versus a C/S; you just have to learn to live within it's limits...

and special training will make no difference..

L.Adamson --- RV6A, Hartzell C/S

 

[Rick6a]

.....Yes, it all comes down to "management" within the limitations.........

Larry,

Certainly what you say in this particular post is perfectly true. However, some of us continue to add to the confusion by repeatedly offering up completely misleading statements in an enthusiastic bid to encourage the use of a C/S prop. One often cited fallacy is a fixed pitch prop is so inefficient when compared to a constant speed prop that an RV so equipped is much more difficult to slow down and statement after statement posted right here would naturally lead anyone (who didn't know any better) to believe that the RV MUST start slowing down "miles and miles" from the airport environment. Others jump on the bandwagon and run with it. The RV community is better served when false information is challenged every time it is trotted out so any potential buyer can make a truly informed decision before opting for which type of propeller to buy. Someone once said if you keep throwing mud, some of it is bound to splatter back.

 

[Toobuilder]

...OR I just might get some transition training and learn how to fly and manage the aircraft I am building...

Agreed 100% - Learn to fly the aircraft as best you can within its limitations. However, when you transition to a new aircraft with new capabilities, you should also adapt your skill set to take advantage of the expanded options. Just like learning how the use of flaps expands your options compared to the Airknocker that didn't have them at all, or use of an autopilot, multi axis trim, EMS systems, etc. MANY of the features common to an RV are completely unnecessary for basic flight, but they sure add options to your management of the flight.

I suspect that if Van designed the airplane without flaps, many of you would be against the idea of adding them... "Learn to manage the flight...", "what's wrong with a slip?..." "who needs the added weight, complexity and cost?" And on and on...

This board sure is entertaining, I'll give you that.

 

[L.Adamson]

Larry,

Certainly what you say in this particular post is perfectly true. However, some of us continue to add to the confusion by repeatedly offering up completely misleading statements in an enthusiastic bid to encourage the use of a C/S prop. One often cited fallacy is a fixed pitch prop is so inefficient when compared to a constant speed prop that an RV so equipped is much more difficult to slow down and statement after statement posted right here would naturally lead anyone (who didn't know any better) to believe that the RV MUST start slowing down "miles and miles" from the airport environment. Others jump on the bandwagon and run with it. The RV community is better served when false information is challenged every time it is trotted out so any potential buyer can make a truly informed decision before opting for which type of propeller to buy. Someone once said if you keep throwing mud, some of it is bound to splatter back.

Rick,

We're (as in plural) are not saying that the F/P prop is inefficient. However, all of us will stake our lives on the "fact" that the C/S prop is far more efficient for slowing down, let alone the climb. Any way you look at it, the C/S is a better tool for managing the airplane. This is NOT false information!
We (as in plural again) think it's misleading to claim that a fixed pitch prop is just about as easy to slow down; if you just know how to manage it. And those are the vibes we get from reading some of these replies. But what the heck, it makes for good hangar talk on the weekends...

And while I'm at it, I have another point to make. In regards to a ground adjustable prop, I fail to see the point. I can't imagine having to remove the spinner every time I want to change from fine to course. I'd much rather have the full C/S for the most available power during the climb, less rpms in cruise; and of course............the built in speed brake for precision landings..

L.Adamson --- RV6A , Lyc 0360, Hartzell C/S

 

[cyberpilot10]

Lost Sleep

I actually lost sleep over this last night !!!!!! but after I finally fell asleep, I think around 0230, I had a vision....LOL I think that if we all install F/P props to save on money. We can take the savings and install a BRS not a BS ha ha. We could inter the pattern at 5,000 AGL at 1 mile out call in range deploy the BRS, drop it in, cut the shoot away and sqeek it in on the numbers. Problem solved. I hope this is a fix for all.....can we move on now LMAO.....

 

[cyberpilot10]

I LOVE THIS PLACE

 

[L.Adamson]

I actually lost sleep over this last night !!!!!! but after I finally fell asleep, I think around 0230, I had a vision....LOL I think that if we all install F/P props to save on money. We can take the savings and install a BRS not a BS ha ha. We could inter the pattern at 5,000 AGL at 1 mile out call in range deploy the BRS, drop it in, cut the shoot away and sqeek it in on the numbers. Problem solved. I hope this is a fix for all.....can we move on now LMAO.....

You had better check the maximum deployment speed of the BRS; as you may not be able to slow down in time with an F/P.....

L.Adamson ---- RV6A & Hartzell "speed brake"

 

[Toobuilder]

... We can take the savings and install a BRS not a BS ha ha. We could inter the pattern at 5,000 AGL at 1 mile out call in range deploy the BRS, drop it in, cut the shoot away and sqeek it in on the numbers. Problem solved. I hope this is a fix for all.....can we move on now LMAO.....

Interesting that you bring this up. An "approach chute" was a common sight when the early jets entered service. Because the throttle response was so slow on a go around, the engines were kept spooled up in the pattern and they simply dragged a open chute around to keep the speed down.

Speed brakes don't seem so silly now, do they?

 

[islandmonkey]

Speed brakes don't seem so silly now, do they?



To be honest Michael, to me, speed brakes are a daft idea. I cannot see a reason for carrying around extra weight and possibly weakening the wing structure for a device that is used 1% of the time.

This is just my opinion however. We choose to build experimental aircraft in order to have the freedom to build in and to put what we want into them. If you choose to install air brakes, I for one would be interested in the outcome. Keep us posted.

 

[Toobuilder]

Speed brakes don't seem so silly now, do they?


To be honest Michael, to me, speed brakes are a daft idea. I cannot see a reason for carrying around extra weight and possibly weakening the wing structure for a device that is used 1% of the time...

Compared to dragging a parachute around...

You might be right, but the same exact points you mentioned above apply to flaps, right?

Lots of airplanes don't have them and those that do are rarely "required". They are heavy, complex, expensive "optional" devices that only add flexibility to how the pilot flies an approach/landing. Most of the time they are just dead weight.

Why is one of these optional devices universally accepted, yet the other is panned? Is it due to a valid technical/operational reason, or simply because of lack of experience among the members?

Next time someone posts why speedbrakes are worthless, type your response and then substitute the word "Flaps" every place you typed "speedbrakes" and see if your argument still hold up. Perhaps we should hear from some people who have actually used them in a piston aircraft - Seems like they are the only ones qualified to comment anyway.

My search for the answer continues...

 

[Danny7]

i don't think your flap = speed brakes comparison quite holds water. the flaps are positioned similar to the ailerons, where there is no fuel tank intrusion, no wing skin modifications. the air brakes i've seen and operated were in the center of the wing, a pocket held out of the fuel tank. they required major reinforcement to ensure no leaking and strengthening of the opening in the skin structure. nearly everyone will agree that flaps are extremely handy devices to have, while due to the cost many owners of the lancair legacy just put a cover plate over the speed brake box.

ps, the primary speed brakes on the legacy are those handy retracting, unfaired gear. plenty of drag on them. add in a c/s and you have all you really *need*.

at this point i think you might be searching for a long time.

edit- in case you missed it, i have time in a plane with speed brakes. all the RV pilots with hundreds or thousands of hours in RVs but not necessarily any in a plane with brakes that are pooh-poohing the idea of speed brakes in an RV have good reason.

 

[islandmonkey]

Why is one of these optional devices universally accepted, yet the other is panned? Is it due to a valid technical/operational reason, or simply because of lack of experience among the members?

Because flaps pitch the nose down and give you a better view of the runway when landing. Also, some flap systems increase wing area and reduce stall speed, leading to a safer slower approach speed along with better runway visibility.

Next time someone posts why speedbrakes are worthless, type your response and then substitute the word "Flaps" every place you typed "speedbrakes" and see if your argument still hold up. Perhaps we should hear from some people who have actually used them in a piston aircraft - Seems like they are the only ones qualified to comment anyway.

I think you will find an earlier post in this thread from me about my experiences in a Grob 109B. In this high aspect ratio motor glider, air brakes are essential for good consistent landings. By the way I am not arguing with you just expressing my point of view with respect to air brakes fitted to RV aircraft.

My search for the answer continues...

Good Luck!

 

[Flyfalcons]

In the planes I fly we consider the use of speed brakes as a failure on our part to plan ahead for our descents. We are usually prodding ATC for descents well before a descent with speed brakes is required. This is was also true in the non-brake equipped slippery twins I flew freight in.

 

[Toobuilder]

OK, I give up! I'm discussing a general capability, and most of you keep jumping right on through to an engineered design, then do a cost/benefit analysis, then shoot it down.

So according to this board, there is a need to manage energy, but speed brakes on piston aircraft are nothing more than a newfangled gimick? OK point taken. Way to think out of the box!

 

[Flyfalcons]

Aircraft design is a compromise. Any discussion about adding capabilities would not be complete without discussing the drawbacks. Having said that, it's your plane. Knock yourself out.

 

[Ron Lee]

Michael, you seem to think that the collective "we" are not listening to you. I would posit that you are not listening the the many RV pilots who don't think it is needed.

In your case, I gave a viable operational way to avoid flying over Edwards AFB and have to drop 4000' and bleed off airspeed from your 190 knots.

I don't recall reading where you even looked at that option. You only want to go airline style ...whatever that is... and point to point with ZERO increase in flight time over the theoretical minimum.

Today I flew to Santa Fe and had to start diverting around the airport zone because I could not announce my arrival. Then I was put on a left downwind to Rwy 33 and was not able to turn base until five miles from the airport.

Return flight was perhaps 15 minutes longer than possible due to diverting around rain showers.

If you need a speed brake, put it in. Personally I think that you would be wasting time but it is your plane.

 

[Toobuilder]

...I don't recall reading where you even looked at that option. You only want to go airline style ...whatever that is... and point to point with ZERO increase in flight time over the theoretical minimum...

Of course I looked at that option... I USE that option, and at one time or another, ALL of the other options mentioned in this thread. And yes, since this is just talk, I'm discussing an additional capability that will replace all those options, not more options.

So far, no one has given me a reason why this option won't work, or will be marginally effective - not one.

The core question is simple: Forgetting cost, weight, structure, planning, etc, will these devices add capability, or not? If the answer is no, with a valid technical reason (such as "the airfoil used on the RV-8 reacts violently with any disturbance of the upper surface and the airplane will come apart at speeds over 150 knots...") Well then, that pretty much seals the deal - the answer is no, it won't work.

However, if the answer is yes, it will work, THEN, and only then, do we discuss the trade off in weight, cost, structure, etc. The cost/benefit might also turn out to be unfavorable, so it would be foolish to make to modification even though it would work.

But my frustration here is you people want to jump all the way to the last step right out of the gate, and that just isn't the way my thought process works. Perhaps it's my failure.

At any rate, I'll drop it. But it has been fun...

 

[Danny7]

i'm not an aeroE, so i don't know how the speedbrake would affect regular flight, although its hard to imagine it would do much other than drastically ruin lift... which is the point.

so, i'm a little curious about where exactly you would put these, and how you'd reinforce both the skin and wing structure to make up for the large cuts in the skins you'd put in there to fit the brakes.

what depth does the brake require? i don't have a legacy wing real handy to go check, i wonder if the RV wing has the space for the standard rdd/ precise flight brake. have you checked that?

 

[Andy Hill]

with a valid technical reason (such as "the airfoil used on the RV-8 reacts violently with any disturbance of the upper surface and the airplane will come apart at speeds over 150 knots...")

I suspect you won't get a reply, because nobody has ever considered it (seriously)...

Given the large range of types they are allegedly fitted to, I am sure they can be fitted to an RV... although who is going to do the structural analysis / limitations / detailed design I am not sure. Only Vans would have the expertise - have you aksed them? Suspect their reaction might be as unkind as the replies on this thread

Speedbrakes have a place in life, but usually only well north of 200K

Andy