Sled engines

martin-av8r

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I am sure with enough time and money some of the features described could be helpful to flying a gyroplane.
Some possible safety feature with electronic throttle - rotor rpm input

reduce power with rotor rpm predetermined number

reduce power or cut power with predetermined lower G number

ground speed - air speed vs rotor rpm , reduce or cut power with rotor rpm number decrease vs speed increase
 
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Vance

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Some possible safety feature with electronic throttle - rotor rpm input

reduce power with rotor rpm predetermined number

reduce power or cut power with predetermined lower G number

ground speed - air speed vs rotor rpm , reduce or cut power with rotor rpm number decrease vs speed increase
As a pilot of a gyroplane I would not want an un-commanded power reduction with rotor rpm at some predetermined number, or g number because it might be the wrong choice.

I don’t know why I would want an un-commanded throttle reduction based on an expectation of mismanaging the power based on “ground speed-airspeed vs rotor rpm.”

Based on my experience flying several Dominators I would not want the engine doing something unexpected in flight because of the power-pitch coupling.
 

Jean Claude

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My recollection is a Rotax 503 is a two stroke; so no waste spark for a 503.
Yes, On Rotax 503, there is a one hump cam that opens two diametrically arranged breakers. Thus, each breaker gives a spark to own cylinder at the right time. No lost sparks nand need of distributor

Sans titre.png
 

Aerofoam

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Yes, On Rotax 503, there is a one hump cam that opens two diametrically arranged breakers. Thus, each breaker gives a spark to own cylinder at the right time. No lost sparks nand need of distributor

View attachment 1155638

My 503 with dual plugs has a wire from each coil to both cylinders, so there is a redundant firing at the bottom of each stroke and each coil covers firing both cylinders.
 

martin-av8r

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Yes, On Rotax 503, there is a one hump cam that opens two diametrically arranged breakers. Thus, each breaker gives a spark to own cylinder at the right time. No lost sparks nand need of distributor

View attachment 1155638
Yes JC you are correct with the old points ignition

single spark plug per cylinder with 2 single tower coil

and your damping box http://www.ultralightnews.ca/rotax503/parts/advisories/boschwiringdiagram.htm

i have 3 rotax 2 stroke here , 2 from sled a 582 with no rave valves and 670 rave valves the 2 motor with single sparkplug per cylinder ignition with single coil dual tower wasted spark with mikuni carbs , and a 618 R.A.V.E valves Rotax Automatic Variable Exhaust with 2 plugs per cylinder and 2 dual tower ducati CDI coil with Bing carbs
 
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martin-av8r

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As a pilot of a gyroplane I would not want an un-commanded power reduction with rotor rpm at some predetermined number, or g number because it might be the wrong choice.

I don’t know why I would want an un-commanded throttle reduction based on an expectation of mismanaging the power based on “ground speed-airspeed vs rotor rpm.”

Based on my experience flying several Dominators I would not want the engine doing something unexpected in flight because of the power-pitch coupling.
I think of a system that you can set exacly like you want it to be

and can always be bypass with a simple push button or switch put every where you want on the machine , on the cyclic or throttle if you want

example i know you have registered a minimum of 0.6 G on your machine

and you have a minimum rotor rpm number you dont want to go below

that you know you are near the trouble and can be bitten if you push more or go lower in the number choice , and with lighter weight and more power the number can drop faster and the trouble come faster

if the power slowly reduce a bit at 0.7 or 0.6 at your own choice , you cant go lower than your choice even with more power , or at your choice exemple 20 rpm before your lower number choice reduce a bit of power you cant go lower with power on or no power reduction or cut

you are a CFI with many hours experience , a new low hours pilot with a powerfull new machine can push a bit more than he can think will be safe and be bitten quickly with some mistake and not very good decision or control move choice or coordination of throttle and cyclic

in one of your post in the thread

Low G and Rrpm decay rate​


----- At one time I imagined if I kept the stick back a forward tumble was impossible.

I discovered this was not the case at the Cable Air Show flying a Cavalon performing my typical routine that I fly in the near centerline thrust Predator.

Near the top of a zoom climb I discovered I had no control of the rotor with the cyclic.

I was not able initiate a turn.

I closed the throttle and as she began to sink rotor control was restored.

I found this experience disquieting and suspect the delay of the rotation from the horizontal stabilizer is what gave me enough time to explore my options.

Upon reflection I realized the horizontal stabilizer is not very effective at low indicated air speed.-----

you know this can possibly have another result with more power and torque like with a 915
in medium low temperature one on board with a lightly loaded machine

all the new higher power motor Gyro accidents with low hours gyro pilot talk here on the forum

that we all try to study and learn from , and help other to not replicate

zoom climb , to steep climb , or to steep for to long time , to much rotor load reduction , to much rotor rpm reduction , dont reduce full power or power before applying front cyclic to put the machine flat

cant do or dont think to reduce power or cut it before cutting the tail or flapping the blades

take off with cyclic not back over running the blades

nearly all these accident apart from bad cyclic move or position

is bad application of power - throttle - or cant or dont remove power at the time you have to

to save your life

just to say that many of the accident if the power have been remove slowly before the fatal outcome , or cut just before

the load on the rotor have not been lost and the blades divergence that cut parts after

the G and rpm number are to low for rotor stability or control

or torque more than the pilot ability experience can compensate and lost control

i know all is in the best training and all the hours to be safe and good is needed to be a safe pilot and also good ADM

if the EFI system is capable of doing safety strategy thing and is put on a new powerfull engine conversion why not try to utilise it ?

i am building a powerfull... gyro motor , i have option to derate it like i want to and put the power output smoother as possible

Thanks Vance for your comments
 
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martin-av8r

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This is a thread about sled engines :)

when we talk about yamaha motor for flying on gyros

the 3 cylinder naturally aspirated rpm and the 4 cylinder Na even more rpm with its shorter stroke

the 3 cylinder turbo can put the stock rotax 915 hp at 5800 rpm at the same rpm on a stock engine

even on 87 octane pump fuel , it is not a high rpm flying motor if you want to

stock motor with stock low flow muffler with stock mapping under 6500 rpm and some mapping touch over 6500 rpm

1660872549021.png


the 240hp mapping dyno chart is on 87 octane pump fuel with Hindle muffler



1660873009435.png
 
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MonkeyClaw

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I'm always curious about how these conversions work 'in the field'. There was a time I thought about taking the V45 from my old Honda Interceptor and putting it on a gyro to see how it would perform. My biggest concerns from the conversions are support and reliability. It's pretty clear that we can eke out additional power from just about any engine. Who's going to support it when the one person doing the design and tooling decides to stop or passes away? What happens when your new Rotax conversion engine eats a cylinder and Rotax says it's been modified so not their problem? Or something happens in the gearbox for a Yamaha conversion but the shop stopped supporting the engine and gearbox?

That's one of the reasons I read these threads. I wish the shops all the best and love to see innovation, but I won't be the one to test their products.
 

martin-av8r

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I'm always curious about how these conversions work 'in the field'. There was a time I thought about taking the V45 from my old Honda Interceptor and putting it on a gyro to see how it would perform. My biggest concerns from the conversions are support and reliability. It's pretty clear that we can eke out additional power from just about any engine. Who's going to support it when the one person doing the design and tooling decides to stop or passes away? What happens when your new Rotax conversion engine eats a cylinder and Rotax says it's been modified so not their problem? Or something happens in the gearbox for a Yamaha conversion but the shop stopped supporting the engine and gearbox?

That's one of the reasons I read these threads. I wish the shops all the best and love to see innovation, but I won't be the one to test their products.
Some try motorcycle engine and gearbox and find that the stock gears are to thin narrow and i think last around 50 hours

they have to put wider gears in the gearbox to make it work

1661212774680.png


Manufactured in high-strength steel, the reduction gearbox wheels are carburized and rectified.
Reduction gearbox is located inside the engine, between the multi-disks clutch damper, and the "flector" of the transmission gearbox.
This way, it is isolated on both sides from engine and propeller jolts.


seems like many people trust small engine conversion and modification company like Viking

Aeromomentum , some Yamaha sellers , Edge is working on a mods 915 with redundant efi i think with dual ecu with a possibility of 160 - 180 - 200 hp

several people mods their rotax , aftermarket sells many parts and do many engine modifications
 

j bird

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Instead of a sled engine--------------------
 

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martin-av8r

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Instead of a sled engine--------------------
Cool Dominator 6 cylinders run smooth ? not the same carburetor in your 2 pictures

i have some parts to put a second permanent magnet alternator option similar to the one in your picture
 

j bird

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Cool Dominator 6 cylinders run smooth ? not the same carburetor in your 2 pictures

i have some parts to put a second permanent magnet alternator option similar to the one in your picture
Yanmar 124190-77201, AC alternator, Jimco J4900 voltage regulator. I had an Aero carb, didn't like it, switched to a 2 barrel Holley, which would freeze up, now back to 1 barrel, one on each head.
 
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martin-av8r

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Hi

Other Sled Engines Info

 

okikuma

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Yanmar 124190-77201, AC alternator, Jimco J4900 voltage regulator. I had an Aero carb, didn't like it, switched to a 2 barrel Holley, which would freeze up, now back to 1 barrel, one on each head.

"...switched to a 2 barrel Holley, which would freeze up." Carb ice?

Wayne
 
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