Suzuki G engines G10,13b,13bb,16b modification.

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aboazeaz

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hi guys:
i have been roaming the net for info on auto convertion for aircraft for more than 6 months.
i have an idea of converting G13b or G13BB or G15 or G16B (whatever is available).
my Q is what are the engine modification(cran,pistons,rods,...) i have to carry out for the engine to make it ready for aircraft use ?
my weight is about 65 kg planning for simple fixed-pitched single-seater.
thank you.
 

aboazeaz

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Assuming you aren't going to stick the prop on the end of the crankshaft, nothing.
Now if no engine modification required . the power curve for G13B says that at 3500 rpm the engine gives about 40 kw (56hp). i beileve this is more than enough
for a single-seater(weighing 152 lb) .the groos weight might approch 830 lb (by comparing power/weight ratio of different single-seaters). i can hook up the propeller directly to the crankshaft .whitout the need for PSRU problems. hopefully it will work as iplanned .of course it would mean high weight penalty.but i think it is a good start for a beginer like me .what are my chances?
 

gearhead

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Wikipedia lists the elevation of Sana'a as ~7400 feet. At that elevation at 0°C, the G13B won't develop more than 40 hp at 3500 rpm, less in higher temps. A general rule of thumb for a flyable airplane is that the power loading (in lb. per hp) + wing loading (in lb. per sq. ft.) should equal less than 25. Thus, at 830 lb gross weight, you will need a wing of 200 sq. ft. or a lot more power with a smaller wing. Your proposal would likely be limited to near-zero wind conditions due to contollability concerns (the low wing loading), if it would fly at all.
 

JamesG

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I'd say your chances of wrecking its main bearings are pretty good. Automotive engine cranks and main bearings are not normally designed to take side loads (ie: be pulled along by the crank). Their thrust bearings are basically just washers that take up most of the difference and keep the crank from wandering around. It has no where near the endurance or strength that a tapered bearing has. This is why auto-conversions have redrives and adapters, not so much to convert rpms.
 

cheapracer

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Wikipedia lists the elevation of Sana'a as ~7400 feet. At that elevation at 0°C, the G13B won't develop more than 40 hp at 3500 rpm, less in higher temps.
That's true for any N/A engine, not exclusive to the Suzuki! ... and why he should run a little turbo with 3 or 4 lbs of boost.


Their thrust bearings are basically just washers that take up most of the difference and keep the crank from wandering around. .
They are to take the loads from the clutch and some of them are very robust indeed but each engine should be assessed individually for the purpose.

the power curve for G13B says that at 3500 rpm the engine gives about 40 kw (56hp). i beileve this is more than enough
I'm not experience enough with props to offer sound advice but I believe you need lower revs than 3500, say 3000 or less? As I mentioned, if you want direct drive then maybe a small, low boost turbo will achieve your goals. At 3 or 4 lbs boost you won't need internal engine mods but note that some people choose to go with aftermarket rods and pistons for an increased safety margin.

Actually not realising you want to go direct drive I would now suggest you consider the G16 SOHC 16 valve engine instead, I have previously mentioned they are not as robust as the G13BB but I was refering to use in upper rpms such as 5500rpm with a redrive, at 3000rpm there won't be any issues at all.
 
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aboazeaz

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Hi gearhead .
Looks like my numbers are not even close to that number you mentioned 25 .
I would really apreciate it if you could give me examples of airplanes parameters that do match that rule of thumb for flyable airplane .
Thanks
 

WonderousMountain

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The engine was designed for turbo.

You need to change the exhaust pipes to a 4-2-1, Get surface gap fancy spark plugs. Switch out some cast iron, a few impressively heavy parts on it. Stock pistons are bunk, but there's not a lot of point in doing a switch-out because they'll be unlikely to break all the same. Single overhead valve seemed like a poor choice, but for some reason my entire head shows only one nick of wear.

Set up dual ignition with a manual switch. You will need a thrust bearing, or some other re-drive setup. There really is no need. Advise on 4 cylinder version.

Do not get 16, they snap cranks, and lack interchangeability. It has been argued that they are more weight efficient but only 2-3 have tried it, and they wear faster for similar rpm.

LuPi
 

cheapracer

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Single overhead valve seemed like a poor choice,


Do not get 16, they snap cranks, and lack interchangeability. It has been argued that they are more weight efficient but only 2-3 have tried it, and they wear faster for similar rpm.
SOHC is fine.

G13A and G16A series have hollow lightweight cranks, stay clear of them.

G16B won't give any issues at all at the 3000 RPM area that's being considered here.

For a high RPM with reduction drive application a G13B or BB would be a better choice but apparently it's not so a G16B will be just fine.
 

WonderousMountain

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Mine has the hollow crank, the B's b bb A and a nomenclature is some of the most confusing I have come across. Single overhead is fine, as I found out. The opinions are not clear on this, but if you stay below 7500 RPM there will be no problems. 4-2-1 exhaust stacks are worth it, as is redundant ignition. Everything else is highly voluntary.

LuPi
 

gearhead

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...... examples of airplanes parameters that do match that rule of thumb for flyable airplane .
Thanks
Most older type certificated slow-and-draggy trainer-types are near the '25' category, or worse. Some are:

Aeronca 7AC 170 ft² 65 hp 1220 lb. 25.95
Piper J-2 178 ft² 40 hp 1050 lb. 32.1
Aeronca C-3 148 ft² 36 hp 900 lb. 31.1

Faster and cleaner, but still scary at 7,000 ft. elevation :

Cessna 150 155 ft² 100 hp 1600 lb. 26.3

These are sea level power ratings and Budd's tests took place at relatively low DAs and less than maximum gross weight.
The engines are also rated at less than 2800 rpm which allows a longer propeller than 3000+ rpm, thus making more thrust per hp at low airspeed.
Taken to an extreme, an R22 helicopter with 124 hp, 25 ft. diameter rotor at 500 rpm hovers at 1300 lb. but a C152 Sparrowhawk 125 hp at 2800 rpm with 69 inch propeller will not climb vertically at empty weight, much less 1300 lb.

FAA Part 103 ultralights typically have wing loading of 4 lb. per ft² and power loading of 18 lb. per hp using a 28 hp Rotax 277 turning a 60 inch propeller at 2422 rpm through a 2.58 ratio gearbox. At 22 combined loading these fly well once airborne, but still have issues with wind near the ground.

A motorglider might be well suited for low power at Sana'a:

Fournier RF4-D 122 ft² 39 hp 860 lb. 29.1

Not being a glider pilot, I don't know how well it would deal with runway winds.
 

cheapracer

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Mine has the hollow crank, the B's b bb A and a nomenclature is some of the most confusing I have come across. Single overhead is fine, as I found out. The opinions are not clear on this, but if you stay below 7500 RPM there will be no problems. 4-2-1 exhaust stacks are worth it, as is redundant ignition. Everything else is highly voluntary.
The reason I know a little about them, albeit no definite expert, is one of my good Mates races one of the World's most powerful G13s, 190 genuine dyno'ed HP with all accessories on. It's in one of Australia's leading Clubman race cars.

His aviation exploits are well known to many as well ..

Bill Sherwood's Aviation page 5 pages of aviation stuff

Bill Sherwoods Home Page
 

aboazeaz

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Thank U gearhead !
that info is helpfull and time-saving for me
I can guess my chances before it is too late .
 

aboazeaz

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Wikipedia lists the elevation of Sana'a as ~7400 feet. At that elevation at 0°C, the G13B won't develop more than 40 hp at 3500 rpm, less in higher temps. A general rule of thumb for a flyable airplane is that the power loading (in lb. per hp) + wing loading (in lb. per sq. ft.) should equal less than 25. Thus, at 830 lb gross weight, you will need a wing of 200 sq. ft. or a lot more power with a smaller wing. Your proposal would likely be limited to near-zero wind conditions due to contollability concerns (the low wing loading), if it would fly at all.
Hi gearhead:
That point on altitude effect on engine efficiency is something never thought about .but what about those new engines with ECM or ECU .I read in the net that those ones can compensate autmatically for the air density change .
 

akwrencher

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The altitude compensation of ECU's is limited to adjusting the air/fuel mixture correctly. It won't help a whole lot with available power. That is a function of air density. To get sea level power at higher altitudes (less dense air) you use a turbocharger. That is the primary function of turbocharged airplanes, btw. To keep constant power at higher altitudes, not to produce more power at sea level. They are sometimes referred to as "Turbo-normalized". If you are gong to be operating at high altitude airports you need turbo or larger engine or bigger wing, as gearhead noted.
 

aboazeaz

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The altitude compensation of ECU's is limited to adjusting the air/fuel mixture correctly. It won't help a whole lot with available power. That is a function of air density. To get sea level power at higher altitudes (less dense air) you use a turbocharger. That is the primary function of turbocharged airplanes, btw. To keep constant power at higher altitudes, not to produce more power at sea level. They are sometimes referred to as "Turbo-normalized". If you are gong to be operating at high altitude airports you need turbo or
larger engine or bigger wing, as gearhead noted.
The idea was that I run G13bb at only @3500 rpm to avoid engine internal modification
And looks like that will give me 40hp with such high altitude
And I found in some sites that with some geared psru,no engine modification required and they run those engines with high 5000-5800 rpm and using some ratio with close to 2:1
If I could run G15,16 at such high rpm with reduction belt psru,l can compensate for the altitude by run the engine at higher rpm values.but I have no idea if the enternal parts can withstand the stress of such rpm.?
 

akwrencher

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Yep, a PSRU will help you out. I don't know those engines very well, except they are supposed to be good. Someone somewere should know what rpm's work well for aircraft use.
 

rv6ejguy

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These engines will run at 3500 rpm for many hundreds of hours. At 8000 feet, you are only going to make about 75% of the sea level rated hp at whatever rpm you are running at. At 3500, your estimate of 40hp is about right. The prop load will determine what rpm the engine spins at wide open throttle.
 
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