Need help to calculate the air intake opening for an RC engine

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firasf1dream
4
Joined: 18 Apr 2014, 21:26

Need help to calculate the air intake opening for an RC engine

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hello everyone,
i am totally new to this subject which treat the air intake needed for an engine, so what i am doing is designing an air intake opening for an RC Zenoah G320RC engine but i need please to know how and what are the info needed ?
here is the pdf for the standard zenoah G320RC, but i am using a tuned version but it's ok because i will learn using the standard info
http://www.google.com/url?sa=t&rct=j&q= ... bs.1,d.d2s

and thanks in advance to everyone
Last edited by firasf1dream on 18 May 2016, 10:16, edited 1 time in total.

Speed_Demon
3
Joined: 03 May 2016, 19:37

Re: Need help to calculate the air intake opening for an RC engine

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firasf1dream wrote:hello everyone,
i am totally new to this subject which treat the air intake needed for an engine, so what i am doing is designing an opening for an RC Zenoah G320RC engine but i need please to know how and what are the info needed ?
here is the pdf for the standard zenoah G320RC, but i am using a tuned version but it's ok because i will learn using the standard info
http://www.google.com/url?sa=t&rct=j&q= ... bs.1,d.d2s

and thanks in advance to everyone
What opening are you trying to figure out...the size of the hole in the car's body?

firasf1dream
4
Joined: 18 Apr 2014, 21:26

Re: Need help to calculate the air intake opening for an RC engine

Post

Speed_Demon wrote:
firasf1dream wrote:hello everyone,
i am totally new to this subject which treat the air intake needed for an engine, so what i am doing is designing an opening for an RC Zenoah G320RC engine but i need please to know how and what are the info needed ?
here is the pdf for the standard zenoah G320RC, but i am using a tuned version but it's ok because i will learn using the standard info
http://www.google.com/url?sa=t&rct=j&q= ... bs.1,d.d2s

and thanks in advance to everyone
What opening are you trying to figure out...the size of the hole in the car's body?
it's the air intake opening

Speed_Demon
3
Joined: 03 May 2016, 19:37

Re: Need help to calculate the air intake opening for an RC engine

Post

firasf1dream wrote:
Speed_Demon wrote:
firasf1dream wrote:hello everyone,
i am totally new to this subject which treat the air intake needed for an engine, so what i am doing is designing an opening for an RC Zenoah G320RC engine but i need please to know how and what are the info needed ?
here is the pdf for the standard zenoah G320RC, but i am using a tuned version but it's ok because i will learn using the standard info
http://www.google.com/url?sa=t&rct=j&q= ... bs.1,d.d2s

and thanks in advance to everyone
What opening are you trying to figure out...the size of the hole in the car's body?
it's the air intake opening
From the picture in the manual you linked..it looked like it had an air cleaner box attached to the motor. If your asking was size hole for that....I'd make the hole 3mm (1/8") clearance on all sides of the filter box. This will allow the engine to move and not damage the body or dislodge the air cleaner.

firasf1dream
4
Joined: 18 Apr 2014, 21:26

Re: Need help to calculate the air intake opening for an RC engine

Post

Speed_Demon wrote:
firasf1dream wrote:
Speed_Demon wrote:
What opening are you trying to figure out...the size of the hole in the car's body?
it's the air intake opening
From the picture in the manual you linked..it looked like it had an air cleaner box attached to the motor. If your asking was size hole for that....I'd make the hole 3mm (1/8") clearance on all sides of the filter box. This will allow the engine to move and not damage the body or dislodge the air cleaner.
thank you Speed_Demon for your reply, can you please clarify what do you mean ?
what i am doing is, i am using a tuned version of that engine which has 30 to 40% of more power, and i will be making an air intake box similar to the Formula 1 car, and in the middle of the air box i will be putting the filter, (the original air box which i have is this one, http://radiocontrolracing.co.uk/WebRoot ... 0666_m.jpg
so what i want to know is how to calculate the hole above the driver's head in the formula 1 car, and then the hole in the middle of the filter

Speed_Demon
3
Joined: 03 May 2016, 19:37

Re: Need help to calculate the air intake opening for an RC engine

Post

firasf1dream wrote:
Speed_Demon wrote:
firasf1dream wrote:
it's the air intake opening
From the picture in the manual you linked..it looked like it had an air cleaner box attached to the motor. If your asking was size hole for that....I'd make the hole 3mm (1/8") clearance on all sides of the filter box. This will allow the engine to move and not damage the body or dislodge the air cleaner.
thank you Speed_Demon for your reply, can you please clarify what do you mean ?
what i am doing is, i am using a tuned version of that engine which has 30 to 40% of more power, and i will be making an air intake box similar to the Formula 1 car, and in the middle of the air box i will be putting the filter, (the original air box which i have is this one, http://radiocontrolracing.co.uk/WebRoot ... 0666_m.jpg
so what i want to know is how to calculate the hole above the driver's head in the formula 1 car, and then the hole in the middle of the filter

OK, You want to make a F1 style scoop, It really doesn't have to be too big, I haven't found any calculations/formulas for it. I did find a good article on the theories behind the development/design changes for drag racing. I think it might help with you'r design.

( http://www.onallcylinders.com/2015/08/0 ... echnology/)

You don't want it to be strong vacuum at Idle, here is a calculator for throttle body sizing
( http://www.hipermath.com/engines/throttle_body_size) could use that and add 20% so their wouldn't be a restriction.

If you made it too large you might have to worry about the air pressure tearing it off. Happened with the 68 hurst/hemi darts and cudas. Plus making it NOT too big will prevent debris/water etc. from getting caught.

The Scoop itself should be a gradual taper, to limit boundary layer separation/turbulence inside the scoop. The taper would allow the air to slow down and pressurize...kind of like the snail on a turbo.

Speed_Demon
3
Joined: 03 May 2016, 19:37

Re: Need help to calculate the air intake opening for an RC engine

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I would use the throttle body formula and cut out circles that match:
the recommended size
+10%
+20%
+30%
and see how it would look "aesthetically" on the car. If it looks odd or missed size try another circle.

Speed_Demon
3
Joined: 03 May 2016, 19:37

Re: Need help to calculate the air intake opening for an RC engine

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You could guess the scale size from a picture of a one you like.

Image

firasf1dream
4
Joined: 18 Apr 2014, 21:26

Re: Need help to calculate the air intake opening for an RC engine

Post

Speed_Demon wrote:
OK, You want to make a F1 style scoop, It really doesn't have to be too big, I haven't found any calculations/formulas for it. I did find a good article on the theories behind the development/design changes for drag racing. I think it might help with you'r design.

( http://www.onallcylinders.com/2015/08/0 ... echnology/)

You don't want it to be strong vacuum at Idle, here is a calculator for throttle body sizing
( http://www.hipermath.com/engines/throttle_body_size) could use that and add 20% so their wouldn't be a restriction.

If you made it too large you might have to worry about the air pressure tearing it off. Happened with the 68 hurst/hemi darts and cudas. Plus making it NOT too big will prevent debris/water etc. from getting caught.

The Scoop itself should be a gradual taper, to limit boundary layer separation/turbulence inside the scoop. The taper would allow the air to slow down and pressurize...kind of like the snail on a turbo.
thank you Speed_Demon for the info, i will read the articles, before i've searched about the theory behind the air box of course general info they give about how to slow down the air and for accoustic purposes

but i couldn't really understand what you were saying because i do not have 1 idea or info about the air going into the engine and i did not take any courses related to that subject in university, if you could please use more simple way and term :/

i do have the air box i showed you in the reply before, i have it physically and dimensions

firasf1dream
4
Joined: 18 Apr 2014, 21:26

Re: Need help to calculate the air intake opening for an RC engine

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Speed_Demon wrote:You could guess the scale size from a picture of a one you like.

http://www.the-border.com/images/D/WRC% ... 2024-2.jpg
hello Speed_Demon,
i have checked the link about calculation that you gave me, it calculate the air intake from the throttle, it gave me for 13 000 rpm a value of 8mm, i took my caliper and checked it, it was around 15mm and you subtract the "door" i don't know the exact term, so i think that would be close to 8, but this doesn't calculate the opening of the air box

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