2 Stroke Cylinder & Case Porting for more HP!

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Armilite

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Yamaha were putting reed valves in road and dirt bikes for over a decade before they put them in their hp-is-king 250 road race bikes. The RD250 had them 12 years sooner than the TZ. It's a reasonable bet that Yamaha knows far more about two strokes than everyone on HBA?
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Knowing How to Build Good Engines is done by most of the Engine Companies, but Marketing those Engine Products is two different things, just as Making the Engines that People really want. In the past, Companies listened to what People/Racers wanted, today they tell us what they decided to give us and at these much higher Prices. If we look at Sled Sales, in 1971 was the year the most Sleds were ever Sold in one year about 585,000+ with about 4 Billion People in the World. In 2016, all the Sled Companies that are left(Yamaha, Skidoo, Polaris, Arctic Cat) and I think there is a brand in Russia, but they only Sold around 185,000 total with almost 8 Billion People today! It doesn't take a Marketing Genius to see whats happening. If these few Companies hadn't diversified into other products, ATV's, Jet Skies, etc., they would have went bankrup. Actually, Arctic Cat I think did file bankrupency once a few years ago. But most of these Engines are pretty well made if taken care of, it's the Human abuse they have to suffer from.

The Sad thing about many Companies, whether Snowmobile(400+ at one time) or Airframe Companies(750+ at one time) they rely on Engine Companies and vice versus! Kawasaki, Yamaha, Suzuki, Honda, their roots all come from Motorcycles where they made both their own Engines and Bikes. Arctic Cat relied on Sachs, Kawasaki, Suzuki, for Engines, and just started making their own Engines about a year ago. Skidoo relied on Sachs and then Rotax and finialy bought Rotax out. Honda has never made a Snowmobile/Snowmobile Engine or Ultralight Engine, I wish they did, they make some of the best small engines in the World. Suzuki made some Sleds, but never made any Ultralight Engines. Some People say, Suzuki Sled Engines were even better than Kawasaki Sled Engines, but both were good Engines if maintained right. Rotax held 85% of the Ultralight/Kitplane 2 stroke market at one time. In the USA, Rotax and Kawasaki Engines were used the most. Kawasaki sold their 340/440 Sled Engines also as Industrial Engines so were easy to buy for Airframe Manufactures and cheaper than Rotaxs 377/447. There was never a Good Tuned Pipe Designed for the Kawasaki's or they would have sold more.
 

Armilite

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A bit offtopic, but sometimes dreams and expensive technologies not so expensive.

We make simple tuning for serial parts. First 3d scanning, make 3d model and finally mill it in 5-axis.
This way 172cc cylinder with integrated head - see on video will weight below 1000 grammes, originally 3400.
[video=youtube;bwgDTPtC_70]https://www.youtube.com/watch?v=bwgDTPtC_70[/video]

One cannot believe, but this milled cylinder become better cooled and have more TBO hours compare stock.
More radical approach mill of cylinder of top tange bullet. Exist some good alu alloys with vanadium and
silver which are superior any used for mass production.

We do experimental production of crancases of foam aluminum (at moment very expensive here and subject
export regulation). The part of foamed aluminum have ~1mm solid surface layer and foamed inside.
Today exist a bit worse, but cheaper approach 3d metal printing. May be already affordable for amateurs.

BTW if someone is interested in expert engine tuning exist cheap, but very good software
http://vannik.co.za/EngMod2T.htm
We got 2 licenses and it worth each cent :)
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How long to Mill one of them Cylinders?

What Scanner do you use, and approximate time to say Scan a Head and get into 3 CAD?

Billet Parts are usually Heavier than Cast Parts so they are better Heat Sinks. My Cast Skidoo 670 Head is 2 lbs, my 670 Billet Race Head with Inserts is 4 lbs. Inserts allow you to change your CR.

WPS Billet Seadoo Head.
 

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jbiplane

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How long to Mill one of them Cylinders?

What Scanner do you use, and approximate time to say Scan a Head and get into 3 CAD?

Billet Parts are usually Heavier than Cast Parts so they are better Heat Sinks. My Cast Skidoo 670 Head is 2 lbs, my 670 Billet Race Head with Inserts is 4 lbs. Inserts allow you to change your CR.

WPS Billet Seadoo Head.
1. Milling cylinders takes about 4 hours. Cannot accelerate, ribs vibrate and produce noise.
Sometimes mill of bullet faster and simpler than rework castings if optimize CNC code.

2. 3d scanner. I have an access to Breuckmann Stereoscan ~0.02mm scan precision.
The head like on your photos are simple and scanning + parametric 3d CAD model could take half of the day.
Air cooled heads much more complicate to scan due narrow deep ribs.

Milled parts can be made much lighter and strong than any castings if design it correctly.
Much better materials and you can use forging to make blanks even better.
 

jbiplane

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V90 color.jpgV90.jpg
V90 variant based on Rotax 503 compatible cylinders will weight about 43kg with electrical starter, end exhaust collectors without resonator.
Hecitate which one to produce:
- 3 cylinders
- 4 cylinder opposite
- 4 cylinder V90
 

Armilite

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View attachment 71385View attachment 71386
V90 variant based on Rotax 503 compatible cylinders will weight about 43kg with electrical starter, end exhaust collectors without resonator.
Hecitate which one to produce:
- 3 cylinders
- 4 cylinder opposite
- 4 cylinder V90
=============================================================

A V4 like Aaens with EFI would be nice for Bigger Planes.
 

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proppastie

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Hesitate which one to produce:
-
whichever you get an order for.

It appears you are setup to manufacture as required. If you do not invest in lots of inventory only produce when you get an order.....you might be able to make money in aviation.
 

Armilite

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In my opinion, we only need (4) Engine Classes to cover most Ultralights & Kitplanes, designed for Max 6500rpms and use 9.5cr:

A Light Weight Single 35-50hp for Part 103. ===> Something like the Simonini Victor 1 Engines, 44hp, 48hp, 54hp. Same Engine, just different Bores & Strokes.

A Light Weight Compact Twin 45-55hp. ===> Something like the Rotax 447

A Light Weight Twin 55-75hp. ===> Something like the Skidoo/Rotax 550 Reed Fed!

A Light Weight Liquid Cooled Twin 75-115hp ===> Something like a Skidoo/Rotax 670(1993-94). A 670 with just a Muffler would make 75hp, and can be Big Bored to a 748.
 

Armilite

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Need smaller ones too for the more glider-esque ones. Some of those flew OK on 15hp. Propasties project is legally limited to 20hp.
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IF, you Standardized on (1) Single Cylinder Engine Design, and Standardized on using just one Stroke, with a Cylinder Designed to accept multiple Size Sleeves you could meet 75% of most peoples needs 20hp to 54hp, and between using just a Muffler vs a Tuned Pipe. For Example: Notice all things being the same, the last two Engines use same Stroke, but just use different Bores, so a 2mm Bore change made 6 hp differene, so 401cc - 382cc = 19cc = 6hp! Now remember, these Simonini's are using a Tuned Pipe only! Since we don't know what % they make over using a Muffler, I'm going to use a low Avg of 25%, it could be higher. could be lower.

So if you only changed the Bore Size:
82mm x 76mm = 401.5cc which = 54hp Absolute with Tuned Pipe! ==> Use just a Muffler 54hp- 25% = 40.5hp!
80mm x 76mm = 382.2cc which = 48hp Absolute with Tuned Pipe! ==> Use just a Muffler 48hp- 25% = 36.0hp!
---------------------------------------------------------------------------------------------------------------------------------
78mm x 76mm = 363.3cc which = 42hp Assumed with Tuned Pipe! ==> Use just a Muffler 42hp- 25% = 31.5hp!
76mm x 76mm = 345.0cc which = 36hp Assumed with Tuned Pipe! ==> Use just a Muffler 36hp- 25% = 27.0hp!
74mm x 76mm = 327.0cc which = 30hp Assumed with Tuned Pipe! ==> Use just a Muffler 30hp- 25% = 22.5hp!
72mm x 76mm = 309.6cc which = 24hp Assumed with Tuned Pipe! ==> Use just a Muffler 24hp- 25% = 18.0hp!
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Now apply that same 2mm = 6hp Info to your Rotax 277. Rotax rated them [email protected] and [email protected] So by Rotaxs Numbers, 150rpms = 2hp. I seriouly doubt Rotax's Numbers, but the Exhaust used does make a difference, even on Mufflers. When R&D Dynoed a 277UL it Dynoed [email protected] For example, my Arctic Cat 275cc Free Air was rated [email protected] with a Muffler and a lower 9.5 CR.

IF, a 2mm Bore change = 6hp.
72mm x 66mm = 268.8cc [email protected] with Rotax Tuned Muffler! Absolute by Dyno Print!
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74mm x 66mm = 284.0cc [email protected] with Rotax Tuned Muffler! Assumed
76mm x 66mm = 299.5cc [email protected] with Rotax Tuned Muffler! Assumed
78mm x 66mm = 315.5cc [email protected] with Rotax Tuned Muffler! Assumed
80mm x 66mm = 332.0cc [email protected] with Rotax Tuned Muffler! Assumed
82mm x 66mm = 348.6cc [email protected] with Rotax Tuned Muffler! Assumed ==> The Biggest a 277 Cylinder could be Big Bored.

IF, 150rpms Increase means 2hp per Rotax's Numbers.
72mm x 66mm = 268.8cc [email protected] with Rotax Tuned Muffler! Absolute by Dyno Print!
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72mm x 66mm = 268.8cc [email protected] with Rotax Tuned Muffler!
72mm x 66mm = 268.8cc [email protected] with Rotax Tuned Muffler!
72mm x 66mm = 268.8cc [email protected] with Rotax Tuned Muffler!
72mm x 66mm = 268.8cc [email protected] with Rotax Tuned Muffler!
72mm x 66mm = 268.8cc [email protected] with Rotax Tuned Muffler!

Victor 1
362cc
Bore (80mm)
Stroke (72mm)
Compression Ratio 9.5/1
Power: 44hp = 32.75kw
RPM 6,500
Weight of the engine with:
exhaust, air filter, propeller
32 Kg /70 Lbs
Reductions Available: 1:2.7, 1:2.8, 1:3
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Victor 1 Plus:
382cc
Bore (80mm)
Stroke (76mm)
Compression Ratio 9.5/1
Power: 48hp = 35.8kw
RPM 6,500
Weight of the engine with:
exhaust, air filter, propeller
32 Kg /70 Lbs
Reductions Available: 1:2.7, 1:2.8, 1:3
-----------------------------------------------------------------------
Victor 1 Super
401.5cc
Bore (82mm)
Stroke (76mm)
Compression Ratio 9.5/1
Power: 54hp = 40.3kw
RPM 6,500
Weight of the engine with:
exhaust, air filter, propeller
32 Kg /70 Lbs
Reductions Available: 1:2.7, 1:2.8, 1:3
 

Armilite

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An 18hp engine with the weight of a 54hp engine will have rather limited appeal
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With the Rotax 277UL used on probably 90% of True Part 103 Ultralights(254lbs), and it's Install Weight (62.9lbs, with B Drive, Electric Start) +4.5 lbs for the Exhaust, equals 67.4lbs versus the Simonini 54hp at 70lbs install Weight, 70 - 67.4 = 2.6 lbs difference.

I seriously doubt your going to find a much lighter 20hp Engine if similarly equiped. His Motor Glider falls into a very narrow margin of Peoples needs, vs most Part 103 Ultralights that usually need 25-35+hp. You also have the Option to Detune an Engine by just turning it less rpms. His needs for his Motor Glider are unquie in that he can only run a Small Prop Size, so to make his amount of Thrust he needs when using it in Direct Drive will set his Rpms. I think he said 6000rpms and figured he needed 20hp.

It would be interesting seeing what the 185UL Install Weight is vs the 277UL. I would still beef up the 185UL PTO more since he is planning on using higher than 5000rpms what the 185UL used. That will add a little more weight to the Install. There are ways to lighten Crank Wheels by drilling large holes and filling them with Plastic(Delrin is what I think they use). A 185UL 184cc/7cc = 25.3 @6500rpms is possible. Porting can add 10% more HP to the overall Numbers.

Option #1:
184cc [email protected] 8.0cr Stock with a Muffler! IF, 1.0cr = 2hp!
184cc [email protected] 9.0cr
------------------------------------------> 87 Octane for above Engines.
184cc [email protected] 10.0cr
184cc [email protected] 11.0cr
184cc [email protected] 12.0cr
------------------------------------------> 91 Octane for above Engines.
184cc [email protected] 13.0cr
------------------------------------------> 93+ for above Engines.

Option #2:
184cc [email protected] 8.0cr Stock with a Muffler! IF, 1.0cr = 2hp, so .5cr = 1hp!
184cc [email protected] 9.0cr
184cc [email protected] 9.5cr [email protected] + use a Tuned Pipe say 25% = 15.5hp! If turning it his 6000rpms would probably give him his 20hp.

184cc [email protected] 10.0cr [email protected] + use a Tuned Pipe say 25% = 16.75hp!
184cc [email protected] 11.0cr [email protected] + use a Tuned Pipe say 25% = 19.25hp!
 
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proppastie

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================================== His Motor Glider falls into a very narrow margin of Peoples needs, vs most Part 103 Ultralights that usually need 25-35+hp.
yes... however as I do this I wounder why most part 103 are so heavy and have so much drag. The proof will be my final weight, and if it survives the load test and every day handling.
 

pictsidhe

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yes... however as I do this I wounder why most part 103 are so heavy and have so much drag. The proof will be my final weight, and if it survives the load test and every day handling.
They are designed to fit the rules. Americans like heavy, sturdy things. So make it close to 254 and maximise the amount of plane they get. The rules state 55kts maximum. To get good climb, you need a large power excess. A draggy plane will have a bigger power excess for climb than a slippery plane. So, more drag means better climb. Assuming both only fly 54kts level at full power.
I'm going slipperry. The legal power for mine is something like 12hp. But I want 20+ for climb. Fortunately, an airspeed sensitive restrictor is legal. Haven't looked at weight yet, but I'd prefer none! I know I'm going to have compromise a tiny bit there. ;)
 

jbiplane

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I am not so optimistic related declared Rotax power.
We never get declares power on dynamometer for their 2-strokes.
They add about 17%...23% to real power (may be they count in small "pony" horses? :) ).
4-strokes 912 and 914 of Rotax correspond to advertised power.

Simonini Victor 1 - the company make good one cylinder paramotors, but their Victor engines very uncomfortable and vibrates like hell.
Better find conmparable snowbike engine from Yamaha or whatelse.
 

Armilite

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yes... however as I do this I wounder why most part 103 are so heavy and have so much drag. The proof will be my final weight, and if it survives the load test and every day handling.
========================================================

Well, the Not very well thought out, Part 103 Rules made some 35+ years ago now, sets the basic parameters. True, many Ultralight Planes are probably way over built(Not Designed by Engineers), so many are over Weight, for meeting these Rules. While every AirPlane design has it's own Weak Points, SAFTEY, should always be your main concern. Part 103 is not about going Fast! The Mojority of Airplane Accidents happen on Takeoffs and Landings.

I have looked at many different planes over the years. For Part 103, one of the Best I have looked at is the Phoenix 103, that use's a Hirth F23 50hp and just makes the 254 lbs and also has the Highest Useful Load of 396lbs. The Hirth F23 Engine is (78 lbs), including Reduction unit, full exhaust, and electric start or (71 lbs) with Recoil start, Reduction unit and full exhaust. HP usually Costs Big $$$ if you have to Buy it. Both the New Hirths and New Simonini's are exspensive. If you can ReBuild an Older Existing Engine and make the needed Improvements to make more HP from either used/NOS parts, and Adapt or Design & Build a Good Tuned Pipe for even more HP, you can save a lot of $$$. Like they say, there's no subsitute for Cubic Inches in making HP, or CC in our case, for making HP! The Phoenix 103 use's mainly 1.0" - .058" 6061 Tubing on 90% of the Aircraft, and I believe 2.0" - .065" on the Spars. I would make the Cabin Hoop Wider to fit more People. I would rather maybe scacfice a little HP/Engine Weight and have a more HD Landing Gear. Most Accidents are from Pilot Error! Use a lighter by 9lbs Simonini 54hp and beef up the Landing Gear. But does it really need 50-54hp to voilate the Part 103 Max Speed Rules? I would bet the 44hp Simonini would work just fine. The amount of Fuel carried (5 Gallons) is going to set the Power Setting used. It would be nice to see these Manufactures Test their Airframes with the different Engines available. It should fly well with a Hirth F33 28hp, 35lbs including exhaust sys. - 40lbs W/re-drive - 45lbs W/elec. start!

Landing Gear Legs.
1-1/4 OD x .065 wall x 1.12 ID
1020 DOM A513 Round Steel Tube
0.83 lb

1-1/4 OD x .095 wall x 1.060 ID
1020 DOM A513 Round Steel Tube
1.18 lb

1-1/4 OD x .120 wall x 1.01 ID
1020 DOM A513 Round Steel Tube
1.45 lb
=========================================================

Airframe:
Buy Metal Online 1" OD {A} x 0.902" ID {B} x .049" Wall {C} 6061-T6 Aluminum Tube (Tubing)
0.1728 lb

Buy Metal Online 1" OD {A} x 0.884" ID {B} x .058" Wall {C} 6061-T6 Aluminum Tube (Tubing)
0.2016 lb

1 OD x .065 wall x .870 ID
6061 Aluminum Round Tube
0.22 lb

1 OD x .125 wall +/- x .750 ID
6061 Aluminum Round Tube
0.40 lb

1 OD x .188 wall x .624 ID
6061 Aluminum Round Tube
0.70 lb

"Those ultralights equipped with powerplants must weigh less than 254 pounds empty weight. In addition, powered ultralight vehicles must have a fuel capacity not exceeding 5 U.S. gallons and be incapable of more than 55 knots calibrated airspeed at full power in level flight. The power off stall speed of a powered ultralight must not exceed 24 knots calibrated airspeed."

Minimum Stall Speed: 24kts / 27.6mph .
Maximum Speed: 54kts / 62.1mph.
Max Fuel: 5 Gallons
Max Weight: 254lbs
 

Armilite

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I am not so optimistic related declared Rotax power.
We never get declares power on dynamometer for their 2-strokes.
They add about 17%...23% to real power (may be they count in small "pony" horses? :) ).
4-strokes 912 and 914 of Rotax correspond to advertised power.

Simonini Victor 1 - the company make good one cylinder paramotors, but their Victor engines very uncomfortable and vibrates like hell.
Better find conmparable snowbike engine from Yamaha or whatelse.
==================================================================

If you look at Rotax's own Power Curve Graph, the 277UL Peaks out at 6000rpms. The 277UL [email protected] used on Scat hover Craft probably used a different Exhaust. An Independent Company called R&D Dynoed a 277UL in the early 90"s and it made Max [email protected]!
http://www.rotaxservices.com/dyno.html#13

Most Companies Round UP HP Numbers. You can also take the same Engine and Dyno it on 10 different Dynos and you will have a +/- % of HP! But it's the best we have.

Most 2 Strokes Singles Viberate at lower rpms and some could be better Balanced! Knowing what your Engines Idle Sweet Spot is crucial. Most Newer Engines have Balance Shafts, but most Hirths are based on Old Piston Port Technology and Simonini's Victor Engines are Reed Fed and don't use that Balance Technology either.
 

proppastie

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It's said in Europe that the easiest way to add 10-20% more horsepower to your race engine is to ship it across the Atlantic...
Why is that? Even here they restrict the intakes on the race cars.
 

proppastie

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Different dyno 'calibration'. US ponys are smaller, despite being ostensibly the same...
Vanity sizing for engines.
Oh sort of like aircraft performance figures, or engine hp curves that no one checks? I think the tractor pull contest came about because of claims of the tractor manufacturers......
 
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