LS3 - It's not just for Corvettes

[carusoam]

Not being a Mooney... it is hard to tell just how much performance the 480hp could give...

310hp in the O allows for 2k’pm in the climb...

The pilot mentioned some vertical rate in thousands of fpm... but I couldn’t tell if that was one or four?

Best regards,

-a-

[cliffy]

On 1/24/2020 at 8:48 PM, Blue on Top said:

@Stephen  I honestly think that the M20 could pass spin testing (if not with minor mod), but the real question is, "Why?"  There is good vertical surface area outside the horizontal wake.  On most models there is rudder below the horizontal (better if it were trapped by the horizontal).  The nose goes very low on entry, but … The loss of altitude is very large.  Spin recoverable only gains the ability to practice loss of control at higher altitudes … not so much in the pattern.  Definitely don't try this at home (or airborne) … especially without a spin chute.

Just as a data point-

I had a conversation with Bill Wheat many years ago in which he related to me that he did a 5 1/2 turn spin in a short body and said he never attempted it again. Said he almost didn't get out of it. Don't know what the factory actually does for spin testing but this was Bill's story to me. 

This is a great thread BTW

Another data point- converting outboard engines for aircraft? One of the first homebuilt helicopters used an outboard engine for power. B. Scramm built the Scorpion helicopter on an Evinrude outboard engine.  

 

 

 

Edited January 26, 2020 by cliffy

[cliffy]

On 1/24/2020 at 9:30 PM, Blue on Top said:

@McMooney  Have you really installed an hour meter in your car? … and is it straight time or tach time?  Not only am I laughing now, you are my hero if you actually have an hour meter in your car.

PS. Trying to use previous data and data from other industries to cut development costs.

All new cars have engine hours recorded for under power and idle conditions being able to be read on the dash at the push of a button. :-) 

[cliffy]

So many thoughts on this great thread-

Why is it most designs of auto/aero engines tie the PSRU to the engine and then the engine to the airframe making the engine block take the aerodynamic loadings? I've wondered about tying the PSRU to the airframe mount (attached to the airframe ) and then just plugging the engine in the back allowing a very light weight engine mount to be used (look at the mounts on a Cessna 206/207) and then the engine just runs like it was a stationary power plant. Crate engines could just be plugged into the back of the assembly. At <10K each you could just plug another one in every 1,000 hrs and be way ahead of the game.  No engine mods needed. Simple interface. Gear box and mount take all flight loads, the engine is along for the ride. In the end you could sell the engine as a 50,000 mile engine. :-)  Just thinkin'

[Blue on Top]

13 hours ago, carusoam said:

Essentially, the power of the engines was great....  but, the weight on the wings wasn’t properly accounted for?

each of the full-up V8s weighed a couple hundred more pounds...

Sounds like some additional engineering and wing parts would be needed to complete the project...

So the Orenda guys seem to have built a usable power plant ...

-a-

Thanks @carusoam!

So ,,, the EPI guys wanted an apples to apples comparison, but … they themselves didn't do that.  The original Shrike engines output 375HP where the Orenda engine outputs 500HP (both geared for more torque).  Which means the twin originally with 750HP was going to be certified with 1000HP, a 33% (250HP) increase!  They mentioned that Vmc was not changed, but I have my doubts about that statement.

The EPI table presented on their website @carusoam quoted above doesn't tell the whole story without a little math (or an added line item).  Numbers can be made to say what you want.  All the certificated, air-cooled engines in the EPI table have a weight/HP ratio of ~2.25-2.3 lbs./HP.  The certificated, liquid-cooled, Orenda engine is only ~1.83 lbs./HP, which is a huge weight savings … if you want/can handle substantially more HP.  Apples to apples the Orenda wins.

In addition, adding weight to the wing lowers the wing bending moment and shear loading to the fuselage.  Landing loads are another story, but they are typically not limiting.  To ease all our MooneySpace minds, the M20s (and the vast majority of small, GA airplanes) have a maximum zero fuel weight equal to the maximum gross weight of the airplane.  IOW, the entire gross weight of the airplane (minus the weight of the wing(s)) can be taken by the wing and fuselage.  Wing bending moment is decreased by fuel weight.  Confusing, but if that doesn't make sense I can explain more if someone asks.  

[carusoam]

We have learned a bit about zero fuel weight as it is an option in some WnB apps...

We also learned it doesn’t apply to our Mooneys...

Which made it easy to forget the rest... 

 

It is clear the HP/weight ratio gets exciting for the V8...

In some cases we can run into too much HP... too fast, too little rudder, too much FF....

Cutting back the HP, using less throttle.... doesn’t cut back the weight...

 

Now... what happens to a wing with heavy engines during flight into vertical gusts?

Maneuvering speed limitations for this?

Maneuvering speeds that need to be lower than stall speeds possible? (Design limit of the laws of physics...)

Best regards,

-a-

[Blue on Top]

8 hours ago, cliffy said:

1) I had a conversation with Bill Wheat many years ago in which he related to me that he did a 5 1/2 turn spin in a short body and said he never attempted it again. Said he almost didn't get out of it. Don't know what the factory actually does for spin testing but this was Bill's story to me. 

2) This is a great thread BTW

Thanks, @cliffy !

1) All certificated airplanes must perform incipient spins (longer of 1-turn or 3 seconds) and recover in 1 additional turn or less in all configurations.  All airplanes approved for spins must perform 6-turn spins (established) in all configurations and recover in 1 1/2 additional turn or less.  The spin program adds ~$2M to certification … if all goes well.   So fixes are quick and easy and others have been up to a year.

2) I agree with you that this thread is wonderful.  All y'all have been awesome!  It's not over yet 

[Blue on Top]

7 hours ago, cliffy said:

1) All new cars have engine hours recorded for under power and idle conditions being able to be read on the dash at the push of a button. :-) 

2) Why is it most designs of auto/aero engines tie the PSRU to the engine and then the engine to the airframe making the engine block take the aerodynamic loadings? I've wondered about tying the PSRU to the airframe mount (attached to the airframe ) and then just plugging the engine in the back allowing a very light weight engine mount to be used (look at the mounts on a Cessna 206/207) and then the engine just runs like it was a stationary power plant. Crate engines could just be plugged into the back of the assembly. At <10K each you could just plug another one in every 1,000 hrs and be way ahead of the game.  No engine mods needed. Simple interface. Gear box and mount take all flight loads, the engine is along for the ride. In the end you could sell the engine as a 50,000 mile engine. :-)  Just thinkin'

1) Again, thanks, @cliffy.  I learned something new again today.  It's a good day.

2) I like the way you're thinking .  Most aircraft engines are aft end mounted, making the engine mount itself the lightest it can be.  Yes, there are some that are bed mounted (like the Bonanza), but this is because the landing gear structure is already there.  We try to put as many/much loadings into one piece as possible.  This way less parts have to be heavily loaded and heavy (weight-wise) … especially if those loads happen at different times.  High wing taildraggers are a great example.  Wing lift loads (the strut) comes into the fuselage at the same place that the gear loads come into the fuselage.  Both loads are very high, but they don't occur at the same time.

As for hard mounting the gearbox, that is a thought … and a tradeoff.  Now all the propeller gyroscopic loads would need to be carried by the gearbox mounting structure, which is (roughly) 50" ahead of the firewall.  Remembering that most tubing failure modes are in buckling, the tube lengths are going from 14" to 50".  This is something that would have to be looked at on a case by case basis … especially if the engine is bed mounted and the nose gear structure is not mounted to the firewall, too (again, Bonanza style).  Great thought!  

[Mooneymite]

10 minutes ago, Blue on Top said:

  Now all the propeller gyroscopic loads would need to be carried by the gearbox mounting structure, which is (roughly) 50" ahead of the firewall.

I think Lockheed thoroughly explored gyroscopic whirl-mode flutter on the Electra.  Don't skimp on the motor mounts.  

[Blue on Top]

1 hour ago, carusoam said:

1) Cutting back the HP, using less throttle.... doesn’t cut back the weight...

2a) Now... what happens to a wing with heavy engines during flight into vertical gusts?

2b) Maneuvering speed limitations for this?

2c) Maneuvering speeds that need to be lower than stall speeds possible? (Design limit of the laws of physics...)

-a-

@carusoam Bummer on this one, but you're correct.  1) Upping the horsepower isn't always the right way to do things.  Matching the HP at a lower weight and cost is.

2a) Ironically, with today's regulations, the wings on small airplanes are designed for gust loading (and not maneuver loading … 3.8G, typically … plus a 50% safety factor).  Inertia is typically good, higher speeds are good, and high wing loadings are good.  Long story, but it's how the airplane penetrates the gust (and how the angle of attack is changed).

2b)  Well ,,, and this is where I'm going to get misquoted .  Yes, Va is determined by Vs and load factor at gross weight, but … the wing is typically NOT the limiting factor.  I'm going to make up easy numbers.  With  a GW of 3.500 lbs. (minus 500 lbs. of wing), the wing has to lift 3,000 lbs. per G.  At a max G of 4, the total wing load is 12,000 lbs.  Now if we lower the weight by 1,000 lbs, the wing at 4G only has to lift 8,000 lbs, so the wing is fine.  In fact in the lower weight case, the wing could take 6G to get to the 12,000 lbs.  BUT, and here comes the kicker, the engine and propeller (at 600 lbs.) weighs 2,400 lbs at 4G … which the mounts are designed for.  But at the lower weight and 6G (same wing load), the engine weighs 3,600 lbs and breaks the engine mounts.  This is true for all fixed weights, including pilot, passengers, baggage, etc.  In the lighter weigh case, the wings won't break, something else will first. 

2c) Maneuver speeds are just a function of Vs and Gmax.  You would have to have a really, really light airplane that has a very high gross weight … I'm not sure if the airliners even have that good of an empty to gross weight ratio.

[Blue on Top]

15 minutes ago, Mooneymite said:

I think Lockheed thoroughly explored gyroscopic whirl-mode flutter on the Electra.  Don't skimp on the motor mounts.  

Thanks, @Mooneymite.  Also don't use the strength of steel when you're building aluminum spars.   …   Google Curtiss-Wright X-100; zoom in on the wing.  You'll see a steel cable strut from the bottom of the fuselage to the outboard wing.   Seems the wing bent up a little more than planned on the first engine run 

[cliffy]

1 hour ago, Mooneymite said:

I think Lockheed thoroughly explored gyroscopic whirl-mode flutter on the Electra.  Don't skimp on the motor mounts.  

2 engines mounted on one wing enhanced the coupling affect twisting the wing root IIRC

[EricJ]

2 hours ago, Blue on Top said:

2) I like the way you're thinking .  Most aircraft engines are aft end mounted, making the engine mount itself the lightest it can be.  Yes, there are some that are bed mounted (like the Bonanza), but this is because the landing gear structure is already there.  

Actually it's because that's the way the engines are made.   Lycomings tend to mount at the rear and can use dynafocal or conical engine mounts.   Continentals generally mount on the bottom even when there's not a landing gear there, e.g., twins like Cessna twins, Barons, etc.

Edited January 27, 2020 by EricJ

[Tim Jodice]

520 and 550 powered Barons are dynafocal mounted. 470 powered baby barons have a bed mount.

[EricJ]

20 minutes ago, airtim said:

520 and 550 powered Barons are dynafocal mounted. 470 powered baby barons have a bed mount.

D'oh...I think Dukes are dynafocal as well, come to think of it.

[Volzalum]

Here is the link to the place that makes the moose engines. They have the engines, PSRU, ignition, etc listed. 
http://www.moosemods.com/moose-ls3-performance-mods.html

[Tim Jodice]

With exceptions like Bonanzas where the airframe is the mount a bed mount looks heavy.

Baby baron bed mount is on top

520/550 baron dynafocal mount on bottom

[Dream to fly]

There is a company in South Africa that is building automotive style engines that run the prop off the camshaft instead of the crank. It appeared at the Oshkosh show in 2016. To me it looked like a GM 3800 with Honda ignition and fuel delivery technology.

I think the real fix is get rid of the FAA death grip on planes below 5000lbs and 4 passenger in both certified and experimental classes. Let the minds of those that wish to explore do so.

The design of the horizontally apposed aircraft engine is functionally perfect. It needs modern technology in metallurgy and control. There is no reason cams, lifters, cylinder walls, and valves fail. There is no reason for cases to crack and fuel systems to go lean or ignition systems to be static timed. Fixing the design will allow mogas use safely. Using today's technology will reduce emissions, increase power, save weight, and actually make it cheaper to repair. But as long as manufacturers hold the patent tight why would they change a cash cow? They did the leg work to get the product to market they know they own it they set the price. They also know their necks are on the line should a problem occur. There needs to be a law to protect manufacturing companies from the law suits. People should be more personally responsible instead of looking for the handout. Most accidents I believe are not caused by parts failing as much as it is poor piloting and maintenance. Let the patent expire and let the certification process ease up to allow competition and prices will drop and performance will change. Some will argue that it will change for the worse. That is in our control if it is bad and nobody buys it it goes away. The performers will always prevail as long as greed doesn't drive the passion.

If the rules could change or someone would have the resources to ask for forgiveness rather than permission that might be the turning point that is needed in GA.

Just my half cent
Joe

Sent from my E6910 using Tapatalk

[jetdriven]

Joe, what kind of death grip does the FAA have on experimental planes? 

[N201MKTurbo]

While you can throw electronic controls on our current engines and make them run on Mogas. They will not make as much power as they do now. It is impossible. There is no combination of fuel mixture or spark advance that will extract the same amount of power out of a lower octane fuel. It just can’t be done. 

You would loose takeoff performance, but could probably get the same cruise performance with slightly higher fuel flow.

The fixed timing we have on our engines is the limiting timing for all the new electronic ignitions. They will increase the timing at reduced MP,  but most of us cruise at pretty close to take off MP. 

The electronic ignitions should really shine at startup and taxi speeds.

[Hank]

33 minutes ago, N201MKTurbo said:

While you can throw electronic controls on our current engines and make them run on Mogas. They will not make as much power as they do now. It is impossible. There is no combination of fuel mixture or spark advance that will extract the same amount of power out of a lower octane fuel. It just can’t be done. 

You would loose takeoff performance, but could probably get the same cruise performance with slightly higher fuel flow.

The fixed timing we have on our engines is the limiting timing for all the new electronic ignitions. They will increase the timing at reduced MP,  but most of us cruise at pretty close to take off MP. 

The electronic ignitions should really shine at startup and taxi speeds.

He did mention eliminating static timing. Variabke ignition timing, which we've had in our cars for decades, would help with performance.

While I cruise at almost full throttle, I cannot cruise "pretty close to takeoff MP". Sure would be nice to get back those 8-9" I lose climbing! But that requires adding a turbo, which current FAA regs make extremely expensive. So . . . . .

[Dream to fly]

Joe, what kind of death grip does the FAA have on experimental planes? 

I was including experimental to cover all bases. Experimental is alot less headaches but still has rules pertaining to owner built and engine repair.

 

Sent from my E6910 using Tapatalk

 

 

 

[Dream to fly]

While you can throw electronic controls on our current engines and make them run on Mogas. They will not make as much power as they do now. It is impossible. There is no combination of fuel mixture or spark advance that will extract the same amount of power out of a lower octane fuel. It just can’t be done. 
You would loose takeoff performance, but could probably get the same cruise performance with slightly higher fuel flow.
The fixed timing we have on our engines is the limiting timing for all the new electronic ignitions. They will increase the timing at reduced MP,  but most of us cruise at pretty close to take off MP. 
The electronic ignitions should really shine at startup and taxi speeds.

So if the engines are designed with better cases and stud configuration allowing more compression and camshafts with profiles that actually work those fixes will not produce a better running engine? It just costs too much to do but to say it's impossible is wrong. The way to make aircraft ownership affordable or cheaper is to own a model or a picture. Volume lowers costs but that would create another problem with every smart guy trying to fly. I've made piece with paying out the ass for antiquated technology so I can fly. Turbines are the way but that is way too expensive for my budget.

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[Tim Jodice]

4 minutes ago, Dream to fly said:

So if the engines are designed with better cases and stud configuration allowing more compression and camshafts with profiles that actually work those fixes will not produce a better running engine? It just costs too much to do but to say it's impossible is wrong. The way to make aircraft ownership affordable or cheaper is to own a model or a picture. Volume lowers costs but that would create another problem with every smart guy trying to fly. I've made piece with paying out the ass for antiquated technology so I can fly. Turbines are the way but that is way too expensive for my budget.

Sent from my E6910 using Tapatalk
 

If you mean a military budget clean sheet new engine that after certification would be about the price of a new PT6A-67A then yes I would think that it could be designed better. Likely will never happen. The engines we have are great at what they do. 

I think he was referring to flying with more power on Mogas. Most engines especially turbo are against detonation limitations hence the need for lead in the fuel. 

What is antiquated about factory engines today? Most all engines have been upgraded over time.

TSIO-520-J that came in early Cessna 402s are case cracking crank snapping engines that once split can not go back on an airplane. TSIO-520NB engines sold today used in Cape air 402 go to 2000 hours like clock work.

Remember small valve lycomings with a 1200hr tbo?

Ask a Mooney Bravo owner if he would like to remove the wet head mod on his engine.

In a twisted way look forward to when I need an engine so I can get rid of the dual mag, flat tappet engine I have for a less antiquated IO-390 regular mag, roller cam, surefly ign, power flow exhaust spinning a scimitar composite MT propeller. None of which existed when my airplane rolled out of the factory in 1985.

 

[aviatoreb]

13 minutes ago, airtim said:

If you mean a military budget clean sheet new engine that after certification would be about the price of a new PT6A-67A then yes I would think that it could be designed better. Likely will never happen. The engines we have are great at what they do. 

I think he was referring to flying with more power on Mogas. Most engines especially turbo are against detonation limitations hence the need for lead in the fuel. 

What is antiquated about factory engines today? Most all engines have been upgraded over time.

TSIO-520-J that came in early Cessna 402s are case cracking crank snapping engines that once split can not go back on an airplane. TSIO-520NB engines sold today used in Cape air 402 go to 2000 hours like clock work.

Remember small valve lycomings with a 1200hr tbo?

Ask a Mooney Bravo owner if he would like to remove the wet head mod on his engine.

In a twisted way look forward to when I need an engine so I can get rid of the dual mag, flat tappet engine I have for a less antiquated IO-390 regular mag, roller cam, surefly ign, power flow exhaust spinning a scimitar composite MT propeller. None of which existed when my airplane rolled out of the factory in 1985.

 

They fly cape air around here, and I fly on them from time to time.  And I am friends with some of the pilots and mechanics.

Their 402's use the TSIO520VB (not the NB) which is very similar but slightly different.

They actually get 2600 hrs out of their engine like regular clock work, using some legal system I do not understand where they fly past tbo on a on-conditioning approved monitoring system.  Of course they are putting tons of hours per year on those engines.  I want to say 2600 is something like 2 yrs.