(Q-1) Propeller Size
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OK, 54" gives us a Basis to go by. I found a Q1 kit AD that was listed on Quickheads that said. "$5,000 for kit including a 750 cc Onan flathead oppossed twin, 42" Crowley 2 blade wood prop.
I thought the Onan was used in Direct Drive, and AD didn't say what HP it was, I assumed it was the 22hp version, so using the Prop Static Thrust Calc I came up with this.
With a (2) Blade 42" Pitched -100rpm for 3500rpm, 42" x 24" = 102.20lbs Static Thrust. Needs 21.753 hp.
Using a 447UL (40hp) and a 54" (3) Blade, I'm assuming 2.58 Ratio, so at 6500rpm, Prop is at 2519.4rpm. If Pitched for -100rpm = 2419.4rpm a (3) Blade 54" x 34 = 186.83 lbs Static Thrust. Needs 38.942 hp.
In Comparison of some Rotax's/Skidoo Engines most used a Muffler:
Skidoo 377F = 377UL (9.6cr) 368.4cc 35hp@6500rpm in a Sled with a Muffler.
Skidoo 377F = 380F (9.6cr) 368.4cc with Dual 30mm Carbs 36hp@7000rpm in a Sled with a Muffler.
Skidoo 380HO (11.2cr) 368.4cc with Dual 30mm Carbs 48hp@7000rpm in a Sled with a Mild +25% Tuned Pipe and Higher CR. With an After Market Tuned Pipe it Dynoed 57.26hp@7000rpm. Was making around 52-53hp@6500rpm.
Skidoo 440F = 447UL (9.6cr) 436.7cc 40hp@6500rpm was a factory Big Bore of the 377/380. Around 1993 they added Dual Ignition and Provision 8 to the 447UL.
Skidoo 503F = 503UL (10.8cr) 496.9cc 50hp@6500rpm.
Skidoo 550F (9.6cr) 553.6cc A 2004 with Dual 34mm Carbs Dynoed 70hp@7000rpm. A 550F has been Big Bored to (81mm x 61mm) 628.9cc, called a 629! They use a New Custom Sleeve & Piston. This guy used a Arctic Cat 81mm Piston.
Now a 277F/277UL, 503F/503UL, 550F, all use the same (4) Bolt Head/Cylinder Bolt Pattern based off a 100mm Bolt Circle (BC). So they all can be Big Bored to at least 81mm, I figure Max 82mm. Old Skidoo Singles used the same Head/Cylinder Bolt Pattern, and I know some were Big Bored to 82mm.
Your Water Cooled Twins, 521/532UL, 580/582/583/582UL, 617/618UL, 670, all use the same (6) Bolt Pattern based on a 100mm BC. 670's have been Big Bored to 82.5mm
A 277F/277UL (72mm x 66mm) 268.8cc can become a (82mm x 66mm) 348.6cc.
Now the 377F/377UL & 440F/447UL used a Smaller 94mm BC Head/Cylinder (4) Bolt Pattern. They both could be Big Bored to a 503(72mm) with a Custom Sleeve.
How a 2 Stroke Big Bore is basically done. Heat Cylinder upside down in Oven supported by (2) Fire Bricks to around 300-350F and the Sleeve will usually drop out, use some Welding Gloves when you see it drop and then pull it out. Then let it all Cool on Work bench. Buy a Blank Sleeve, the Bore is always under size, so will need Bored and Honed to final Size once Installed, and Transfer Ports over to it. The Simplest way is to draw a Detailed Port Map in a Simple 2D Cad program that you can just Print it out 1:1 and Glue on Blank Sleeve and then Cut Out most of the Ports keeping close to the lines, but leave a little 1/16' to 1/8". Then Bore Aluminum Shell for Big Bore Sleeve OD. Put Sleeve in Freezer over night, then Heat Shell and it will drop right in, you only have a few Seconds to align the Ports Up. Like on a 670, the Stock Std. 78mm Sleeve is 3.332" OD and the 82mm Big Bore Sleeve is 3.415" OD. All Stock Sleeves can be Bored 2mm = .080" Over if you can find a Piston. Many of these Big Bore Sleeves can also be Bored 2mm Over also. Custom Size Pistons are usually around $180ea.
A 503F/503UL is a Piston Port Engine. A 550F is a Reed Fed Engine(Better). Reed is on the Cylinder, not the Case. Both use the same (4) Bolt Pattern. So it's possible to put 550F 76mm Cylinders on a 503 Case! You have two Options, Weld a small Block of Material for the Reed Port on the Side of Case about 2.0" Long by 1.0" High and 3/4" Thick and then Machine it, or just use Pistons that have the Side Ports and Block Off Reed Boost Port which is like 1/4" x 3/4". Some People Weld it closed, some epoxy Glue some Aluminium into the Port, some have used JB Weld.
On Avg a 2 Stoke turning 6500rpm using 11.5cr with proper Size Carb and a Good Wide Band Tuned Pipe, it takes 7cc to make 1hp.
277 268cc/7cc= 38.2hp@6500rpm
277 82mm Big Bore 348.6cc/7cc= 49.8hp@6500rpm
377 368cc/7cc= 52.5hp@6500rpm
447 436cc/7cc= 62.3hp@6500rpm
503 497cc/7cc= 71hp@6500rpm
550 553cc/7cc= 79hp@6500rpm
629 628cc/7cc= 89.7hp@6500rpm
670 669cc/7cc= 95hp@6500rpm Rotax Ricks 670 Dynoed 93hp@6350rpm!
Simonini Singles: All use 9.5cr and a 34mm Carb and a Tuned Pipe!
362cc = 44hp@6500rpm
382cc = 48hp@6500rpm
Hirth F-36 313cc 28hp@6500rpm Single, 9.5cr with a Muffler! Small 34mm Carb. 313cc/7cc= 44.7hp.
In a message dated 9/27/2019 7:55:06 AM Central Standard Time, Q-Performance@... writes:
Our ratio is 2.24 on the B gearbox and I have a dual carb motor. I was also building full dual chambers and expecting mid 40s or so.toggle quoted messageShow quoted text
The prop is a Precision out of Utah if I recall. Ground adjustable obviously.
2.58 would spin this prop too slow.
At 06:53 PM 9/27/2019 +0000, you wrote:
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OK, you use the B Gear Box, 2.24 Ratio. If you use 6500rpm/2.24= 2901.8rpm, 54" x 22 Pitched -100rpm for 2801.8rpm = 250.56 lbs Static Thrust and needs 39.133 hp at 77F.
When you say " I was also building full dual chambers and expecting mid 40s or so." Do you mean Dual Tuned Pipes, Dual Mufflers, please clarify?
If you compare the 377UL (35hp@6500rpm) used a Single Bing 54, 36mm Carb vs the 447UL (39.6hp@6500rpm) with a Single Bing 54, (41.6hp@6500rpm) with Dual Carbs, both used 9.6cr. They Both used Rotax's Muffler. 447UL(436.7cc) - 377UL(368.4cc) = 68.3cc difference = 6.6hp difference!
Skidoo 377F (368.4cc) 9.6cr 36hp@7000rpm
Rotax 377UL (368.4cc) 9.6cr 35hp@6500rpm Bing 54 36mm Carb
Skidoo 380F (368.4cc) 9.6cr 36hp@7000rpm pair of 30mm Carbs
Skidoo 380HO (368.4cc) 11.2cr 48hp@7000rpm pair of 30mm Carbs with a Mild Tuned Pipe.
Skidoo 380HO (368.4cc) 11.2cr 57.26hp@7000rpm pair of 30mm Carbs with aftermarket Tuned Pipe.
447UL (436.7cc) 9.6cr 39.6hp@6500rpm Single Bing 54.
447UL (436.7cc) 9.6cr 41.6hp@6500rpm Dual Carbs = +2hp. Would a 38mm Carb give you the same result?
If, you look at Rotax's 447UL Engine Performace Graph on that 447UL Spec's page, you can see it was starting to Starve for Air with the Single Carb around 5300rpm. Both are affected by the too Restrictive Exhaust starting around 5500rpm. If, you print out that Power Graph and then Extend the Grid Lines for Rpm & HP, and then Extend the Red Power line with a Ruler, that Engine should make about 53hp@7000rpm, about 47hp@6500rpm! The Power Line Extended intersects at 35 kw@6500rpm = 46.93577 hp. So you have to ask yourself, WHY isn't it making that Full HP? Notice, this Power Band is with a Rotax Muffler! 46.9hp - 41.6hp = 5.3hp your losing! See Carb Flow below.
#1 Reason, usually to Small A Carb Setup.
#2 Reason usually the Exhaust Muffler is Too Restrictive.
#3 Small Intake Ports
HP = Engine CFM@rpm/1.5
That CFM is what the Engine makes at a Specific Rpm, not what the Carbs can Flow.
What different Carbs can Flow:
A 30mm Carb can Flow 59.8cfm/1.5= 39.9 hp x 2 Carbs = 79.8 hp
A 32mm Carb can Flow 68.1cfm/1.5= 45.4 hp x 2 Carbs = 90.8 hp
A 34mm Carb can Flow 76.9cfm/1.5= 51.3 hp x 2 Carbs = 102.6 hp
A 36mm Carb can Flow 86.2cfm/1.5= 57.5 hp x 2 Carbs = 115.0 hp
A 38mm Carb can Flow 96.0cfm/1.5= 64.0 hp x 2 Carbs = 128.0 hp
Now as a Smart Sled Racer, Engine Builder once explained it to me. A 2 Stroke Intake Port Window is only open about 50% of the Time, so it Gulps Air. When Sizing a Carb go at lest 20-25% Bigger.
447UL (436cc at 6500rpm) at 100% VE = 100 cfm = 67hp
447UL (436cc at 6500rpm) at 95% VE = 95 cfm = 63hp
447UL (436cc at 6500rpm) at 90% VE = 90 cfm = 60hp
447UL (436cc at 6500rpm) at 85% VE = 85 cfm = 57hp
447UL (436cc at 6500rpm) at 80% VE = 80 cfm = 53hp
447UL (436cc at 6500rpm) at 75% VE = 75 cfm = 50hp
447UL (436cc at 6500rpm) at 70% VE = 70 cfm = 47hp
447UL (436cc at 6500rpm) at 65% VE = 65 cfm = 43hp
447UL (436cc at 6500rpm) at 60% VE = 60 cfm = 40hp
So more than likely it's a combo of Carb Size, since you picked up +2hp vs Rotax's Exhaust being too Restrictive. The Single Carb vs Dual Carb were about equal till about 5300rpm.
Example Intake Ports: On my Skidoo Single 335 (20hp@5500rpm) Intake Port is 25mm x 47mm = 1175sq mm, and my 340 TNT Single (26hp@6500rpm) is 29mm x 47mm = 1363 sq mm. Both same Bore & Stroke, 9.0cr vs 10.5cr. That equals to 16% more Air. 335 rated at 20hp@5500rpm + 16% = 23.2hp with just Porting! Both Intakes can be Safely widened to 51mm. 25mm x 51mm = 1275 sq mm and 29mm x 51mm = 1479 sq mm. The TNT uses a Muffler with Bigger Tubes and Bigger Holes inside, so less Restrictive. Also 32mm Carb vs a 38mm Carb.
Stock 440F/447F with an R&D Aero Tuned Pipe. RD-1 Test says with a 34mm Mikuni!
With their RD-1 Tuned Pipe it made, 52.4hp@6500rpm
With their RD-2 Tuned Pipe it made, 46.4@6250rpm.
For Comparison, a 380HO with 11.2cr Dual 30mm Carbs with aftermarket Tuned Pipe, Dynoed 57.26hp@7000rpm, was making 52-53hp@6500rpm. So R&D's 447 Tuned Pipes were very Mild.
In a message dated 9/28/2019 7:44:13 AM Central Standard Time, Q-Performance@... writes:
Yes dual tuned chambers. They wrap around under the engine such that they are fully inside the cowl.toggle quoted messageShow quoted text
We never got around to flying it since the stories of engine seizures when the throttle was closed on clean airframes. I would be more compelled to finish and fly this plane if I could make it not try to kill me. I was also on a 2100' runway, not much room for errors.
Lanny Rundell who was the dealer I bought the carbon spars from, the 1st customer set FWIW, he had a Kawasaki sled motor with 72 Hp on his Q1. Chambers were hanging out side the fuselage so it was draggy. He was betting mine might have been faster, clearly that was never determined.
At 08:12 PM 9/29/2019 +0000, you wrote:
We had built this airframe to fit a radiator aft of the seat with the plumbing inside the left armrest. Logic started setting in and we realized cabin heat would be an issue.toggle quoted messageShow quoted text
A few years back after chatting with you about motors I realized the coolant pipes could be under the plane along the centerline with the speedbrake contoured to wrap under the two tubes.
One concern is the 447 I have only had the factory oil/ pickling in it such that holding the prop flange it was not interested in turning.
I doubt it is real tight but need to look at the crank to see if moisture got to it.
With the sweet looking carbon props available today they might have enough twist to be efficient.
As sweet looking as this wood prop is it may be best to leave it hanging on my living room wall.
This airframe holds 22 gal fuel so it should be able to get somewhere and back home.
At 08:12 PM 9/29/2019 +0000, you wrote:
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From my observation of Dual Tuned Pipes on Sleds vs Single Tuned pipe, on a 617 & 670 with Dual Tuned Pipes made about 12hp difference, so on a 447 probably 4hp. I personally don't think it worth the Extra Cost, Extra Weight, Extra Head ace to make it all fit.
With the Ceramic Coatings used on Piston Tops, Combustion Chambers, Cylinder Exhaust Ports, Wye Pipe, and your Exhaust Tuned Pipe you can reduce your Temps by 20%. On the Wye Pipe & Tuned Exhaust you use it on the Outside and Inside.
If you see a Burnt/Melted Hole in the middle of a 2 Stroke Piston, that's a Jetting Problem, Carb Boot Air Leak Problem, Case Seals Air Leak problem.
If you see a Piston Top Pitted, or Broken that's a Detonation problem.
Seizures: If you see a Piston Melted on the Sidewalls it's either a Clearance problem, or Oil problem. It can also happen when Cylinders are not Bored & Honed Correctly. They both should be done with a Torque Plate.
IF, your Engine has been in Storage for a Long Time 5+ Years, I would do a Basic New Seals & Gaskets & Inspection for Peace of Mind.
For some reason I'm not able to attach photo's here, but R&D Aero had a nice compact Tuned Pipe Design.
Yes, I would go with the Carbon Prop.
A Kawasaki 440 (68mm x 60m) 435.9cc and a Rotax 447 (67.5mm x 61mm) 436.7cc are both about same 436cc. If Both are turned same 6500rpm with an Avg Tuned Pipe with a 94% VE is about 63hp Tops. My Skidoo 670 with a Tuned Pipe Dynoed 115.7hp@7750rpm = 94% VE.
277 268cc at 6500rpm at 94% = 39hp!
377/380 at 6500rpm at 94% = 53hp!
440/447 at 6500rpm at 94% = 63hp!
503 497cc at 6500rpm at 94% = 71hp!
521/532UL at 6500rpm at 94% = 75hp!
580/582/583/582UL at 6500rpm at 94% = 83hp!
617/618UL at 6500rpm at 94% = 89hp!
670 at 6500rpm at 94% = 96hp!
For a Kawasaki 440, 436cc turning 7500rpm at 94% VE = 72hp! Most Fanners were rated at 7000-7500rpm, most Water Cooled were rated at 7750-8000rpm.
In a message dated 9/30/2019 7:42:59 AM Central Standard Time, Q-Performance@... writes:
Even when this 447 was factory new Rotax was calling for seal replacement before flight, Outers at least.
Back then single chambers were scowled at, the better tech today I expect makes them work better. It's not like airplane use calls for peak power or efficiency. I just want better than a big can hung off it.
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Yes, Rotax's TBO was 300hrs or 5 years, which ever comes first. Older Case Seals and Carb Boots and other Plastic/Rubber parts didn't like Alcohol thats in Gas since about 1989. Most of them Parts have been upgraded by now. I have 6 Sleds, 93 Arctic Cat 550 EXT, 94 Yamaha V Max 600, 95 Yamaha V Max 600, 98 Skidoo MXz 670, 1976 Arctic Cat 2000 275 Free Air, 1971 Skidoo 292 TNT. The first (3) Sleds have never been touched on the lower ends, the 98 Skidoo I think had a New Top End done, just before I bought it. I'm doing the 1976 Arctic Cat 275 right now, finally got all the parts. I got it with the Motor half tore apart, it had a light Seizure. The 1972 292 TNT was being used as a Race Sled when I bought it, so I'm sure it has been apart.
Yes, today you have the Old First Generation Single Stage, and now Dual Stage, and Triple Stage Tuned Pipes. I have never seen any real Proof the Tripple Stage is any better than the Dual Stage. I don't think many people really understand Tuned Pipes, how Important each part is in it's Design. Racers are only interested in Max HP at their Max Rpm. Many of them Sled Tuned Pipes have terrible Power Bands. Today with Spread Sheets like Excel, you can Graph them Dyno Numbers. On a Good Tuned Pipe, you should be able to draw a straight line from say 3500rpm to just past your Max rpm it was designed for, Avg is 150rpm past max rpm, which today 6500rpm is Industry Standard. Only the 618UL was rated at 6750rpm.
Sadly, there were very few Tuned Pipes that were ever made for these Rotax UL Engines, only R&D Aero and one other brand, I forget who now, and none were ever Designed for the Kawasaki 340/440 Engines for our Max 6500rpm. There is at least 4-5 different Tuned Pipe Software programs out there that are pretty simple to Design one in today. With more Small Shops and even some Home Shops getting CNC Plasma Cutters, even CNC Water/Laser Jet Cutters, and with Mig/Tig Welders getting cheaper, you can build your own fairly cheap, just your Time & Material, which Material you can buy from about any Scrap Yard for less than $20. Welding and Fabing it all up is what takes so much Time. You can Buy off eBay a Tuned Pipe for these Small RC Engines for less than $100,
and for these Mopeds 50cc-150cc for $180. Dirt Bike Tuned Pipes avg $200-$400.
For Designing any Tuned Pipe you have some Set Standards, Like Max 6500rpm. In the Software you have Narrow to Wide Power Band, which for Plane use you want a Wide Power Band. In the Free, Simple Exhaust Calc program for Android phones, you only need this Info:
Engine CC: 436
Exhaust Duration: ??mm
Exhaust Port Width: ??mm
Exhaust Port Height: ??mm
Exhaust Port Length: ???mm
Target Power(HP): ??
Target Rpm: 6500rpm
Coefficient(Power Band): 2.0
Unless you Port your Cylinder & Case, all of these Numbers are Hard Numbers, except HP desired. Like your 447 (67.5mm x 61mm) 436.7cc was rated 40hp@6500rpm. You know by the simple 7cc to make 1hp Gen Rule, 436cc/7cc= 62.3hp is Max HP. You can Design a Tuned Pipe for different HP, say 45hp, 50hp, 55hp, 60hp. If you Plot out them different tuned Pipes in a 2D CAD program, you will see how the Tuned Pipe changes Shape.
40hp + 10% = 44hp
40hp + 20% = 48hp
40hp + 30% = 52hp
40hp + 40% = 56hp
40hp + 50% = 60hp
40hp + 55% = 62hp
On the Skidoo 377/380 using 9.6cr with a Muffler (36hp@7000rpm) to 57.26hp@7000rpm = 59%. +9.26hp. That was using a Higher 11.2cr and a aftermarket Tuned Pipe. The Standard 380HO used a Tuned Pipe and was rated at 48hp@7000rpm. Aftermarket Tuned Pipe about 19% better than the Factory 380HO Tuned Pipe.
If you use the Simple Rule: 1 kw for 10 kg, MTOW, Rule of Thumb. What does your Plane with the 22 Gallons and You Require?
In a message dated 10/1/2019 8:41:38 AM Central Standard Time, Q-Performance@... writes: