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Rocket Glider.....

Power off landings

I have a little secret that's given me a measure of safety and confidence in dealing with engine failures (simulated or otherwise): Do some glider flying.

Glider pilots learn from the start that engines aren't necessary if you're able to manage energy through different means. Here are a few things I've learned from flying gliders that are also 100% valid when your RV gets quiet:

1) In any steady-state descent, note that there's a spot on the canopy at which the sight picture of the ground is neither rising nor falling as you progress. That's the spot you'll hit if you just continue on your current flight path. The sight line through that spot is your glide angle for the condition of flight.

For your aircraft, it's good to get familiar with this nominal glide angle of the aircraft in a simulated engine out condition at best glide speed. Even with everything ticking away in normal fashion, a good seat-of-the-pants feel for this angle will allow you to judge when you're within gliding distance of a landing location. This is good stuff to know when flying over populated areas, water, trees, or anything else that isn't a flat concrete slab with numbers painted on both ends.

2) Rule #1 for cross-country flying in a glider is to always have a landing spot in mind, and within reach of your current position. It's a great carry-over habit in VFR power flying to have a similar sense of the available landing spots along your route of flight, and whether or not they're within reach.

3) Know your best glide speed. Glider guiders call this "best L over D" (L/D), and it's critically important to fly at this speed to maximize your distance over ground.

In practice, it's important to quickly get to that speed (even if it means a pitching into short climb when the engine quits), because it'll give you the greatest gliding distance and therefore most landing options. The maximum L/D of almost any aircraft occurs with flaps fully retracted.

4) In practicing landings, it's good to develop a feel for how much control you have over glide angle through things like flap deployment and slipping. This enables you to intentionally aim for mid-runway on final and bleed off excess energy when you know you've got the runway made. Coupled with tip #1 above, and some practice, you should be able to consistently and safely make power-off spot landings in VFR conditions. Glider pilots learn that on 1-mile final, you can easily put the glider in the ditch short of the runway, or land 1/2 mile past the far fence, all by controlling the glide angle on final. Our RVs don't have quite so much glide path control, but it's still good know how much is available and how to use it.

Also, for IFR flying with the current crop of experimental autopilots (e.g., the TruTrak units with altitude hold), consider setting the autopilot's minimum airspeed parameter to the best glide speed of the aircraft. This way, if Alt Hold is activated when the engine quits, the autopilot will automatically transition to the best glide angle as the airspeed decays. Who knows if it would ever come to your aid, but it might save your bacon by keeping things stable while you hit Direct To - Nearest on the 430.

Cheers,

Matthew
 
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I'll second that

I have a little secret that's given me a measure of safety and confidence in dealing with engine failures (simulated or otherwise): Do some glider flying.

Matthew

Absolutely correct.

I will add that this is useful for any situation where you are tempted to pull back when low and slow.

I bounced a landing at Columbia really bad a few years ago in my Stinson, fully loaded on a warm summer day. Pushed in the throttle for a go around, and even though the engine ran fine, the rate of climb was pretty pathetic.

Keeping the nose down to gain speed probably saved us from a crash---either stall/spin, or hitting the trees and hills off the runway.

Believe me, keeping from pulling the yoke required all my concentration, your natural instinct is to PULL.
 
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Add my 2cents worth

Depending on whether you easily make the field or not try to leave a few extra knots for wind gradient close to the ground and round out, so that you are still flying the roundout and not just transitioning into the high drag high sink rate.

Rob
 
FWIW....

....In my state of half-asleep, after landing the other day, I taxied in and pulled the prop back instead of the mixture. I caught my error quickly but did notice that the prop had gone to max pitch almost immediately, at only idle power.

So I experimented on the next final approach....With little to no power on final, the blades were already on the flat pitch stops, with quite a bit of ensuing drag. I decided to pull the prop control fully out...high pitch...WOW, the increase in speed and glide was immediately apparent!

A neat brake or no brake on final to be used as necessary.

Best,
 
A stuck sniffle valve or a large leak will prevent the engine from idling below a certain point but they usually will run fine at high power.

Sounds like the flow divider was the culprit.

Bob, you certainly might be correct on this, but based on what? Don Rivera indicated there was a little wear, and the divider was rebuilt. But, it is not reasonable to imagine the flow divider causing overall fuel flows to suddenly go to half, is it? One could imagine mis-matched flows due to some failure, but not these symptoms. Or, maybe I do not understand the design at all.

Something is still lurking...
 
I haven't been active here for a long time, but I was searching for something else on VAF and came across this post...

I had forgotten some of the details, but I had exactly the same problem again in January and I now definitively know the cause of the original problem, and I apologize for not coming back here and sharing it sooner.

I fly my Rocket a lot. Nearly 200 hrs per year, it has around 2800 hours on it, and the current engine has over 1000. Here is what I have learned.

The Air Flow Performance fuel divider has a screen in it, and it is the finest screen in the system.

I was flying in to Carlsbad CA from Palm Springs and as I got close I started losing fuel flow. Not a great place for an engine problem. I stayed very high as long as possible and did an overhead let down to a landing.

I took the flow divider apart and back flushed the screen with carb cleaner. The cleaner was very dark and the particles were so small that they were barely visible. But after quite a bit of back flushing the liquid became clear and it solved the problem.

If you have an airflow performance fuel divider I would recommend either cleaning the flow divider screen, ( I am sure Don would not recommend this, but it is a very simple piece of hardware) or sending it back to Don and having it cleaned on some sort of schedule. When it plugs, it doesn't seem to happen slowly. The fuel flow drops rapidly. And if it happened in flight, and the engine quit at altitude, I would definitely try pulling the mixture to see if the debris would settle out of the screen to buy some time to find an airport.

Why Don never shared with me or never realized that the problem was a plugged screen, I will never know. Maybe like it did for me, when he first tested it, it worked fine, and in the normal course of inspection, he cleaned it and that unknowingly solved the problem.

Needless to say, this is a real issue that has now happened to me twice and needs to be understood in the community. I don't know if it would be possible to backflush it without disassembling it??? I would be interested to know if anyone has tried that.
 
Doug,

Thanks for the follow-up. This is indeed good to know.

It is concerning that a vital component has "the finest screen in the system".

I would prefer that nothing vital has a screen finer than the fuel filter. If something can make it through the fuel filter, then it should be harmless to the system. Then, you make the fuel filter big enough so that if there is a significant quantity of stuff that can plug it, it still flows fuel, until it is really loaded. Obviously a fuel filter would be one of the first places to look for a flow issue, and you would find it plugged. Problem solved.

Of course there is always the problem of contaminants getting introduced downstream of the fuel filter - which is why vital components have their own screen. There is probably no perfect solution. But I don't like the idea that some fine contaminant in the tanks could make it through at least two other screens and then fowl the last component in the system.
 
I haven't been active here for a long time, but I was searching for something else on VAF and came across this post...

I had forgotten some of the details, but I had exactly the same problem again in January and I now definitively know the cause of the original problem, and I apologize for not coming back here and sharing it sooner.

I fly my Rocket a lot. Nearly 200 hrs per year, it has around 2800 hours on it, and the current engine has over 1000. Here is what I have learned.

The Air Flow Performance fuel divider has a screen in it, and it is the finest screen in the system.

I was flying in to Carlsbad CA from Palm Springs and as I got close I started losing fuel flow. Not a great place for an engine problem. I stayed very high as long as possible and did an overhead let down to a landing.

I took the flow divider apart and back flushed the screen with carb cleaner. The cleaner was very dark and the particles were so small that they were barely visible. But after quite a bit of back flushing the liquid became clear and it solved the problem.

If you have an airflow performance fuel divider I would recommend either cleaning the flow divider screen, ( I am sure Don would not recommend this, but it is a very simple piece of hardware) or sending it back to Don and having it cleaned on some sort of schedule. When it plugs, it doesn't seem to happen slowly. The fuel flow drops rapidly. And if it happened in flight, and the engine quit at altitude, I would definitely try pulling the mixture to see if the debris would settle out of the screen to buy some time to find an airport.

Why Don never shared with me or never realized that the problem was a plugged screen, I will never know. Maybe like it did for me, when he first tested it, it worked fine, and in the normal course of inspection, he cleaned it and that unknowingly solved the problem.

Needless to say, this is a real issue that has now happened to me twice and needs to be understood in the community. I don't know if it would be possible to backflush it without disassembling it??? I would be interested to know if anyone has tried that.

Doug - what can explain why, on a given flight, the system can deliver adequate take-off fuel flows but then a short while later in the flight it can't deliver but a small fraction of that? I could see peak fuel flows at take-off power slowly being reduced as the screen gets more and more clogged, but a sudden change?
 
Steve

Do not be concerned with your spelling. Bill L did the exact same thing to me seven years ago.

Like I said then; "Impressive, an engineer and an english major."

GM
 
I would just offer this up , seeing the age of the thread. Yep, there's a screen in there. It's in the maintenance manual (which Don provides for free on his website). I think he also recommends 12 year overhauls for the fuel control and 8 years for the divider. It looks like the OP is kind of past both of those.

I know--- no one tells us what to do for preventative maintenance, and in the AB world everyone tends to ignore recommended overhauls. We've been through that argument on the props.

The reality is we really can't wait for things to fail and expect to pull over to a cloud and get things right. Some failures can have drastic consequences.

Everyone should really take the time to read all of the maintenance manuals for installed components on their airplanes. Then create a schedule sheet.

Shameless plug, but get the Maintenance Manual for Vans RV Aircraft. I wrote it for reasons such as this.

These aircraft will only outlast us if we take care of them. :)

Vic
 
I haven't been active here for a long time, but I was searching for something else on VAF and came across this post...

I had forgotten some of the details, but I had exactly the same problem again in January and I now definitively know the cause of the original problem, and I apologize for not coming back here and sharing it sooner.

I fly my Rocket a lot. Nearly 200 hrs per year, it has around 2800 hours on it, and the current engine has over 1000. Here is what I have learned.

The Air Flow Performance fuel divider has a screen in it, and it is the finest screen in the system.

I was flying in to Carlsbad CA from Palm Springs and as I got close I started losing fuel flow. Not a great place for an engine problem. I stayed very high as long as possible and did an overhead let down to a landing.

I took the flow divider apart and back flushed the screen with carb cleaner. The cleaner was very dark and the particles were so small that they were barely visible. But after quite a bit of back flushing the liquid became clear and it solved the problem.

If you have an airflow performance fuel divider I would recommend either cleaning the flow divider screen, ( I am sure Don would not recommend this, but it is a very simple piece of hardware) or sending it back to Don and having it cleaned on some sort of schedule. When it plugs, it doesn't seem to happen slowly. The fuel flow drops rapidly. And if it happened in flight, and the engine quit at altitude, I would definitely try pulling the mixture to see if the debris would settle out of the screen to buy some time to find an airport.

Why Don never shared with me or never realized that the problem was a plugged screen, I will never know. Maybe like it did for me, when he first tested it, it worked fine, and in the normal course of inspection, he cleaned it and that unknowingly solved the problem.

Needless to say, this is a real issue that has now happened to me twice and needs to be understood in the community. I don't know if it would be possible to backflush it without disassembling it??? I would be interested to know if anyone has tried that.

Doug, thanks for following up on this. I have this system and have installed it exactly as the manual describes, and have taken apart the fuel divider to check for debris before first flight after ground runs. I cannot recall seeing a filter - will check this more closely at next annual. There is also no flow divider filter mentioned in the manual.

AFP has the 75 micron filter at the fuel controller inlet, and apparently the even finer filter in the flow divider.

Perhaps my math is bad, converting between microns, mm, and inches, but I don't understand why we would need a filter finer than the recommended 125 microns - if that's the equivalent of 0.005 in and our injector nozzles are 0.015 in and the slots in the divider can be cleaned with 0.006 in feeler gauges.

I bought a new 40 micron filter that I'm considering installing in place of my 125 micron at the next annual. I'll of course do plenty of ground runs to make sure that the pressure drop is not a problem. The supplier says that it should flow "up to 900 GPH (15.0 GPM) with less than 1-PSI pressure drop."

https://aeromotiveinc.com/product/40-micron-stainless-steel-element-for-12635/

Thanks again for flagging this for the many people that have the AFP system.
 
Owning a Rocket I can tell you that the title of this thread is deceptive! It does not glide, it falls in a somewhat controlled fashion!
 
The EVO version will surprise you!

Owning a Rocket I can tell you that the title of this thread is deceptive! It does not glide, it falls in a somewhat controlled fashion!

The EVO version has a min stall speed of less that 50KTS. It does not fall unless provoked.

Doug: do you recall the problems I had when trying to demo that plane to you in Midland? Ended landing short and cleaning out the screen per Don's instructions. I did not know about the problems with the same clogs later on...happy to hear you got thru the problems.
 
So with all the their two, they're too there , my fowl is a foul? I guess I can live with that.;)
 
The EVO version has a min stall speed of less that 50KTS. It does not fall unless provoked.

Doug: do you recall the problems I had when trying to demo that plane to you in Midland? Ended landing short and cleaning out the screen per Don's instructions. I did not know about the problems with the same clogs later on...happy to hear you got thru the problems.

+1 on the EVO, With the prop back, even with the mixture in ICO, the EVO has remarkable glide ratio as long as you stay above 110 kts. I am guessing 12-1. With the prop on the low pitch stops it comes down much faster. and when you get below 90 kts the nose starts coming up and it pays off speed pretty quickly. I have an aerobatic prop, so if I lose oil pressure, it goes to coarse pitch.
 
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