Where?

[Mitchg07261995]

Hello, I think I found my 3d project on the haas cnc mill that we have for my class at warren tech next year. I got a print for a COX .049 Babe Bee crankcase which normally has a displacement of .049 cubic inch. It is glow fuel powered and uses a glow plug, any ways. I plan to make the engine 10 times the size of a stock .049, which will give me a displacement of 800cc or 48.782 cubic inches
What I need, is to find a supplier for a large chunk of aluminum, im talking 12'' long, 8''wide, and 8'' thick
thanks
for people that dont know what one of these engines is or looks like, or need an idea of size of a .049 here is one of mine...

 

[Philjoe5]

large chunk of aluminum, im talking 12'' long, 8''wide, and 8'' thick

Wow, that's 75 pounds of ally. I've gotten billets for $3/lb at best from a local machine shop so that's where I'd go first, a local machine or fabrication shop. Any on-line suppliers will have a hefty shipping charge.

The Baby Bee has a bore of 0.4" so 10x that and you're looking at a bore of 4" - a fairly serious engine.

Good luck with your project

Phil

 

[rcfreak177]

Wicked,

I have a Cox Babe bee .049 engine, It is my favourite one, Bloody thing left an almighty gash on my finger once when I put it in the wrong place.
800cc you could nearly power a Cessna when that is finished.

What are you going to call it, maybe A 49.0 Beastie bee

Baz.

 

[canadianhorsepower]

10 times the size of a stock .049, which will give me a displacement of 800cc or 48.782 cubic inches

my calculator tells me .049x10=.49cu not 48.782 cu

and getting a single carb for an 800cc 2 stroke ,good luck

 

[tornitore45]

Quote: my calculator tells me .049x10=.49cu not 48.782 cu
and getting a single carb for an 800cc 2 stroke ,good luck
End of quote.

Volume scale with the cube 10 times longer 10 times wider 10 times taller.

Is rare to see a single cylinder engine with 800cc displacement.
Vibration will shake it into destruction.
Also scaling a large number present structural problems
Stresses and thermal do not scale properly, that is why an elefant is differently shaped than a mouse on steroid.

I would not scale it up above 200cc max, that will power a decent motorcycle.

 

[///]

Oops, didn't mean to delete my post, meant to edit it when I saw Mauro's reply was essentially the same as mine regarding the volume.... (10x in every dimension = 10 x 10 x 10 = 10^3 = 1000x)

That will learn me for opening a thread and walking away to have dinner then coming back and not refreshing the thread before posting.

 

[mu38&Bg#]

It has been done before, thought not quite that size. I would not go over 3/4" bore without a ring and then you have the giant ports to deal with.

 

[canadianhorsepower]

Volume scale with the cube 10 times longer 10 times wider 10 times taller.

if that's the case fine,
but that's not written on his post

 

[Mitchg07261995]

my calculator tells me .049x10=.49cu not 48.782 cu

and getting a single carb for an 800cc 2 stroke ,good luck

i did this calculation to find the displacement

bore is .406*10=4.060"
stroke is .377*10=3.770"
pi/4*(bore^2)(stroke)(number of cylinders)
so
3.14/4(4.060^2)(3.770)(1)= 48.78239002

 

[canadianhorsepower]

It has been done before, thought not quite that size. I would not go over 3/4" bore without a ring and then you have the giant ports to deal with.

Nice work I can just imagine how much that exaust port would grab the piston ring if the port is scale:fan:

 

[Mitchg07261995]

I see what you guys are saying about not going over 200cc, structural, and getting a single carb on it. I am thinking just make the crankcase and call it good, I dont want to spend more time and money on an engine that wont run right or shake itself to death. Plus this crankcase would be a cool thing to show my future employer once i get a job in a year or two

 

[mu38&Bg#]

I had nothing to do with the engine above. I know of it through some hobby forums and that is has run. I don't know anything about how it was built.

 

[Bastelmike]

i did this calculation to find the displacement

bore is .406*10=4.060"
stroke is .377*10=3.770"
pi/4*(bore^2)(stroke)(number of cylinders)
so
3.14/4(4.060^2)(3.770)(1)= 48.78239002

Some mess with imperial obviously

in metric:
bore is 103 mm
stroke is 96 mm

cylinder volume: 0.785 x bore² x stroke
= 799,494 mm³
= 799 cm³
= 0.8 litres

Thats the volume of one larger tractor cylinder

Mike

 

[///]

if that's the case fine,
but that's not written on his post

Except... it is:
"I plan to make the engine 10 times the size of a stock .049"

Note: size, not displacement.

 

[canadianhorsepower]

Some mess with imperial obviously

4.06 inch =103mm
3.77 inch = 95.7mm
pi/4=.7854

displacement=.7854x4.06 square(16.48360x3.77=48.80cuin
or
displacement= .7854x103square(10609)x95.7=797cc or .8ltr

maybe the mess is that you don't know how to convert cu/in to litre
cu/61 = litre so 48.8cu/in /61=.8 litre
or .8 litre x.61 = 48.8 cu/in

 

[canadianhorsepower]

Except... it is:
"I plan to make the engine 10 times the size of a stock .049"

Note: size, not displacement.

that's your way of interpretting it.
Size could be displacement10x.049 or physical size 10x.40

but neither displacement or physical was included in the text
I assume one and you assume the other one
it only prove that 2 wrong don't make a right
or 2 right doesn't make one wrong
but lack of information can be miss leading for anyone

 

[///]

that's your way of interpretting it.
...
but neither displacement or physical was included in the text
...

Mine and everyone elses interpretation it would seem.
Yes, displacement was included in the text, you directly quoted his displacement in an attempt to correct him, remember?
I haven't assumed anything, there was no lack of information. He stated the increase in size, the correct increase in displacement and even included the following:

a large chunk of aluminum, im talking 12'' long, 8''wide, and 8'' thick

 

[canadianhorsepower]

Mine and everyone elses interpretation it would seem.
Yes, displacement was included in the text, you directly quoted his displacement in an attempt to correct him, remember?
I haven't assumed anything, there was no lack of information. He stated the increase in size, the correct increase in displacement and even included the following:

Quote:

I did some research to improve your lack
of vocabulary, you don't need any improving
in obstinate

 

[///]

I did some research to improve your lack
of vocabulary, you don't need any improving
in obstinate

True to form that is in evidence all over this forum, you are resorting to insult, yet again.

Maturely played sir

 

[mu38&Bg#]

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