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Advice Needed: How to survive a flameout in a Skymaster A-10

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Advice Needed: How to survive a flameout in a Skymaster A-10

Old 12-21-2015, 11:26 AM
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dubd
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Default Advice Needed: How to survive a flameout in a Skymaster A-10

Gentleman,

I need the RC Jet community's collective brainpower on techniques and prevention to survive a flame out with a twin. More specifically a Skymaster A-10. I lost my first A-10 due to a single engine flameout. The plane snapped upwards abruptly, I powered down to idle and managed to level the plane out, but as I gently gave power to get to the runway, the plane snapped again...

I've heard of a few people who lost their A-10s because of a flameout. Is that just the way things are with this plane? Is this inherent to the design of the SM A-10? Does changing turbine mounting positions help?

So, I'm on airframe #2 and to be honest, my last ineptness at recovering the plane has me on edge. So I'd like some thoughts on ways to give me a fighting chance to recover from a flameout. Open to all ideas from stick inputs to technology solutions (gyros).

Thanks in advance!

DD

Last edited by dubd; 12-21-2015 at 02:04 PM.
Old 12-21-2015, 11:28 AM
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highhorse
 
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Rudder gyro.
Old 12-21-2015, 12:01 PM
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DrScoles
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subscribed… I brought this up before with no definitive answer. The Skymaster F-14 has the thrust tubes diverge slightly laterally and Anton took off and landed the plane with one engine. Would this help the A-10?
Old 12-21-2015, 12:10 PM
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Vincent
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Hi Dantley
A friend of mine had a flame out with a Mibo shortly after take off and had no trouble flying around on one motor. It was only when he dirtied up the jet it became unstable and it snapped and went in.
Vin...
Old 12-21-2015, 12:21 PM
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DrScoles
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Originally Posted by Vincent View Post
Hi Dantley
A friend of mine had a flame out with a Mibo shortly after take off and had no trouble flying around on one motor. It was only when he dirtied up the jet it became unstable and it snapped and went in.
Vin...

Great, so we just come in hot and belly land it…. LOL
Old 12-21-2015, 12:36 PM
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AKB
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With my Mibo A-10 I had a flame out and it was a non event. I suspected it when I saw the old white smoke, but went through the whole flight without a problem. Only when I was in downwind that I noticed sluggish performance and that just confirmed the one engine running. I throttled up just a little bit to keep up the airspeed. When came for landing just pulled back the throttle and greased her in. Probably one of my best landings ever.
I had other problems with my A10 that was my fault. May she rest in peace.
Building another 5.5 right now and am putting in the CB electronics telemetry system for this one that will give data on both engines.

Good luck on the next one DUBD.
Old 12-21-2015, 12:44 PM
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mr_matt
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dubd I have no idea, but there never stops me from posting!

This is a good primer on Vmc, which I believe is applicable in this case (Vmc being the minimum controllable airspeed to operate a twin on one engine):

http://www.langleyflyingschool.com/P...20-%20Vmc.html

I have seen this behavior with another plane, an old school Aviation Design SU-27. On downwind one of the turbines quit and the resulting spin was unavoidable. The only option (looking back) was to just pull power and go in straight.

I think the actual VMC (based on physics involved) is peculiar to each plane. Short of knowing the actual Vmc of the A-10 model (derived from scary testing I would think) I am not sure how much this theoretical knowledge helps.

Last edited by mr_matt; 12-21-2015 at 01:19 PM.
Old 12-21-2015, 12:53 PM
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mick15
 
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Dub, it seems to me your difficulties could well have been associated with the manufacture of your A10. I have been flying an SM A10 for the past three years and whilst there have been difficulties assymetric thrust has largely been a non event. My model has two Kingtec 210s which in the early days had issues resulting in many one engine flame outs, apart from one insedence when the model was a long way off and I was oblivious to the flameout a large amount of power caused it to begin to flick, I immediately reduced elevator and power and was able to complete the circuit and land.

If you're interested I have videos of assymetric flight, one of which shows me making use of the condition to perform an almost perfect lomcevak.

m
Old 12-21-2015, 01:15 PM
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CraigG
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It's all about maintaining aircraft control by counteracting the asymmetric yaw generated by the operating engine. This must be done with rudder and airspeed must be adequate (fast enough) to provide sufficient rudder authority to overcome the thrust yaw. With the high thrust to weight turbines we fly our jets with it's easy to overpower the rudder, especially on scale jets and with the SM A-10 in particular.

When an engine quits in flight, immediately:
1. Apply opposite (up to full) rudder to counteract yaw*
2. Lower the nose to maintain/increase airspeed
3. Add power (but only to the extent the resulting yaw can be countered by rudder. This may even require a reduction in thrust if speed is low)

*Gyro on rudder may potentially help with step #1 but may not command enough rudder. It will certainly not help with steps 2 and 3.

If speed is slow and altitude is too low to trade for airspeed, the best option may be to stay at or near idle on the good engine and land straight ahead. With a properly designed and powered twin, such as the MIBO A-10, a flame out can (and have been) safely managed and flown to a controlled landing. With it's higher thrust to weight and higher wing loading, the SM A-10 has proven to be much more difficult to control single engine than the MIBO. Nevertheless, quick recognition and the principles/procedures described above are valid and offer the only hope of recovery for an inflight flameout.

Craig
Old 12-21-2015, 01:55 PM
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dubd
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Matt, thanks for the link. I'll be reading up on VMC.

Mick, can you elaborate on your comment about manufacture of my A-10. I'd love to see your videos and learn from them.

Craig, thanks for the insight. I need to turn what you've described into muscle memory.
Old 12-21-2015, 01:59 PM
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bidrseed2
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I have the smaller SM A10. I rotated the exhaust tubes 30 degrees away from vertical to give some differential thrust.
i had the misfortune of taking off one time with an engine at idle only AND the iGyro in rudder heading hold mode. I thought it felt "funny" during the flight but it wasn't until after landing I realised what had been the problem. It still required rudder in the turns, but the iGyro took care of most of the roll and yaw so landed safely.
in future if I lose an engine, I'll be switching to rudder HH mode AFTER I've stabilised the flight path, OR if it's uncontrollable.
Not that I've been brave enough to simulate the same situation again though��
Old 12-21-2015, 02:07 PM
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ravill
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So, it sounds that the Mibo maybe more forgiving with one engine? However, it is still susceptible to the snap of death? Especially when slowed down?

My experience with twins has been with props. (p-38's and B-25's)

Engine out = throttle to idle and (this is the most important part) NEVER touch the throttle again. Unless of course, it is to kill the remaining engine.

Doubly so when going slow.
Old 12-21-2015, 02:15 PM
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Here is one of my videos the RH engine quits at 3m 10secs.

https://youtu.be/FeCvuyzFzLk?list=FL...DJcUNuf7YKFO-A

https://youtu.be/SQPugtho5Oc?list=FL...DJcUNuf7YKFO-A

A friend had an FEJ A10 it was a total disaster.

m

Last edited by mick15; 12-21-2015 at 02:27 PM.
Old 12-21-2015, 02:20 PM
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dubd
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Originally Posted by mick15 View Post
Here is one of my videos the RH engine quits at 3m 10secs.

https://youtu.be/FeCvuyzFzLk?list=FL...DJcUNuf7YKFO-A

A friend had an FEJ A10 it was a total disaster.

m
Very similar to what happened to mine. Looks like you kept the power up. Is that correct?
Old 12-21-2015, 02:39 PM
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mick15
 
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Sure speed makes the vertical stabilisers more effective and obviously as you reduce power asymmetric thrust reduces. The second video may interest you.

I think the reason the Mibo one is more forgiving is it has lower wing loading.

m
Old 12-21-2015, 04:01 PM
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Zeeb
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Dub, in full scale what you describe happening is known as a "VMC maneuver" in a multi-engine aircraft. So read up on that link, it should help answer some questions.

That said, the A-10 is going to be a handful on one engine as the rudders don't really have that much authority and as the wing loading goes up, so does the VMC or "Minimum single engine control speed" can't remember if one of you guys already spelled it out. But it's the slowest speed at which the control surfaces can counter act the asymmetric thrust of one engine. Now you might think that the engines being that close to the fuselage would make it so the problem isn't so bad. I've not flown an A-10 but I have flow some smaller biz jets and I can tell you that when the instructor does a simulated engine failure, you better be on your toes.

If you're too slow, the wing on the failed engine side will drop as the other rapidly comes up and if you don't stop it, it'll roll over and head for the ground. With props, you firewall the throttles, props all the way forward, mixtures all the way forward while you try to straighten things out then identify the failed engine. Might sound ridiculous but inside the airplane it can be initially difficult so that's why all the engine controls go forward.

Turbine? Bit different story as you have no increased prop wash over the tail feathers for some increased authority which hits almost instantly. Turbine has none of that, takes time to spool up and then more time to accelerate the airframe.

I'd say the best course of action would be as someone already talked about; get the nose down for some airspeed, if it still wants to roll or pulls hard to one side I'd reduce the power a bit until you can control it. Be aware that you may not be able to regain control if the airspeed is to low when it happens.

Hope that helps......
Old 12-21-2015, 04:06 PM
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Dantly,

I don't mean to sound too cliche, another thing to remember it to turn away from the dead motor. If your right motor is out, avoid making right turns. If you keep the asymmetrical thrust on the inside of your turn you will be a lot less likely to get into a snap/spin. If you are flying a right had circuit change to a left hand if the wind allows

Keep your bank angle shallow and avoid high power.

On my YA F-14 I programmed one of the inside sliders to be a "Super Rudder Trim". It gives me almost full rudder deflection on a mix using the slider. The real trick is figuring out which way to slide it in a panic situation

Best of Luck!

SteveK
Old 12-21-2015, 04:08 PM
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Zeeb
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Originally Posted by stevekott View Post
Dantly,

I don't mean to sound too cliche, another thing to remember it to turn away from the dead motor. If your right motor is out, avoid making right turns. If you keep the asymmetrical thrust on the inside of your turn you will be a lot less likely to get into a snap/spin. If you are flying a right had circuit change to a left hand if the wind allows

Keep your bank angle shallow and avoid high power.

On my YA F-14 I programmed one of the inside sliders to be a "Super Rudder Trim". It gives me almost full rudder deflection on a mix using the slider. The real trick is figuring out which way to slide it in a panic situation

Best of Luck!

SteveK
As I was trying to say..... Another trick is to bank into the good engine by about 5 degrees, that's how they do it to get the VMC number.
Old 12-21-2015, 04:10 PM
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ravill
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Wowza,

One can't have all these thoughts when an engine quits!
Old 12-21-2015, 06:29 PM
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invertmast
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Originally Posted by ravill View Post
Wowza,

One can't have all these thoughts when an engine quits!
Heres the easy one.


Fly the damn plane! Lol
Old 12-21-2015, 06:36 PM
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Zeeb
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Originally Posted by invertmast View Post
Heres the easy one.


Fly the damn plane! Lol
Originally Posted by ravill View Post
Wowza,

One can't have all these thoughts when an engine quits!
Well as I said, it can initially be difficult to determine which engine quit. So.... and I'm not sure how you'd do this; practice so the response is automatic. My F-14 is actually setup so that one engine can be operated at a time with the other at idle. Wouldn't bother me to have an instructor pull an engine in a full scale, but the idea is not appealing with my new toy.... lol
Old 12-21-2015, 06:39 PM
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CraigG
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Originally Posted by stevekott View Post
The real trick is figuring out which way to slide it in a panic situation



SteveK
True. In a full scale there are additional clues/tools that we don't have with RC (i.e. "step on the ball", "step on the good engine", etc.) As a rule however, the yaw from the good engine will quickly induce a roll action which you will instinctively counter with aileron. Once you realize the roll is from the loss of an engine, applying rudder in the same direction as aileron will produce the correct rudder input.

Craig
Old 12-21-2015, 06:40 PM
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Zeeb
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Originally Posted by Zeeb View Post
As I was trying to say..... Another trick is to bank into the good engine by about 5 degrees, that's how they do it to get the VMC number.
Originally Posted by ravill View Post
Wowza,

One can't have all these thoughts when an engine quits!
At any rate, the above is true and accounts for the fact that you see a bunch more crashes/deaths with an engine failure on a twin than you do a single; guys get pre-occupied with trying to figure out which engine and why it quit, in the mean time they get slowed down because they are not paying attention until the VMC demonstration occurs and then it's all over.
Old 12-21-2015, 10:11 PM
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In full Scale prop twins they always talk about a critical engine. That's the one where if it quits the torque and P-factor of the remaining motor compounds the asymmetrical yaw.

Not as much an issue in jets, no prop, some torque effect.

As the old pilot joke goes, the critical engine is the one that is still running. Because it is the engine that will take you to the scene of the crash!

Like said above, don't get too distracted trying to figure out too much when the most important thing to do is fly the plane.

If you pull back the power you can just glide. Then add just a little power to keep from loosing altitude while keeping the airspeed up.

Easy to say Don't Panic, Don't get Distracted. The challenge is doing it
Old 12-21-2015, 10:17 PM
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dubd
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Lots of good info here.

When my last A-10 died I had no idea which engine quit as it snapped upwards and rotated. In Mick's video you can hear him come off the power when the plane snaps and then apply power in the dive. He was then able to pull out and have command of the plane. I came off the power, but never applied power again. I did manage to glide the plane back towards the runway, but just a hair of power was enough to cause it to snap again. In the future I'll use telemetry and gyros to give me a chance and I think I'll be less gunshy about applying power after the snap.

Last edited by dubd; 12-22-2015 at 01:40 AM.

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