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Ace Hobby . Esprit Model . Thunder Power RC

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Gasser Model RC Helicopters > Velocity Stacks?
 
 
SteveH
rrProfessor
Location: Texas

Just wondering, who uses velocity stacks and do you think they actually improve performance? Do you have any supporting gasser heli data other than "gut feel"?

I used one on an earlier gasser and felt it mostly was a carburetor noise amplifier. I'm currently using a modified stock type air filter.

Thanks for your replies.

SteveH

SteveH
Magnum Fuel
AMA76186
08-28-2003 Over year old.
 
 
Cessna
Senior Heliman
Location: Tucson, Arizona

I've used them on a G62 in gas powered planes before. In all honesty I couldn't tell any difference in engine perfromance.

I doubt there would be much value added to using on in a heli.

Just a guess!

Steve Cass
Tucson
08-28-2003 Over year old.
 
 
BIGRCR
Veteran
Location: Easley, South Carolina

What experience I have with a velocity stack on my G231 is that it does not cause any of the problems that I expected it would. I expected it to mess with the mid range needle since usually a velocity stack adds improvement at wide open throttle and usually will make a gas engine "burble" around what we use as hover throttle. This does not generally cause a problem with a plank but can cause all kinds of troubles for the gas helicopter for obvious reasons.

I have swapped out my standard air breather that was supplied with my G231 with the Zenoah velocity stack and back again a couple of times. The needles had to be set a little richer with the velocity stack. I am not sure if that is attributed to a need for more fuel demand due to more air being used by the motor, or , a need to open the needle valve a bit more due to less fuel being drawn through the same ports from less fuel draw.
Due to the fact that it does have a bit more performance, I would say the first condition may exist. I could be wrong

Later,

BIGRCR- John Garst
08-28-2003 Over year old.
 
 
AGRAV8
rrProfessor
Location: Mosquito Coast......Houston Texas

GOT one.....

on my Hanson modded G-23.......no issues to complain about....and it makes great power........

GOOD guy list-39, BAD guy list-0
08-29-2003 Over year old.
 
 
Cessna
Senior Heliman
Location: Tucson, Arizona

Tom,

If you can see a power difference on the Dynometer, do you think that the difference is significant enough to make an improvement in your heli's performance?

They definately increase the intake noise!

Steve Cass
Tucson
08-30-2003 Over year old.
 
 
Al Magaloff
rrMaster
Location: 12,199 Posts- Enough Time Wasted. See Ya!

Tom, that's the Harley loud pipe mentality! Take a 40HP motor with stock exhaust, put loud pipes on it, power goes down to 32HP, but man oh man, it sounds faster.
08-30-2003 Over year old.
 
 
Naomi
Elite Veteran
Location: Ontario, Canada

Velocity stakes.. IMHO rather risky.. No air filter.. could have sucking up anything (grass, pollens, dibris in the air) in Hover or flying into the carb, and accumulated more cruds inside the carb. K&N filter not bad a bad idea.either Just my opinion, never tried one , but that's my presumption.

Naomi
08-30-2003 Over year old.
HOMEPAGE  
 
 
BIGRCR
Veteran
Location: Easley, South Carolina

Risky, is that why we do not use air cleaners on the glow motors???

Later,

BIGRCR- John Garst
08-30-2003 Over year old.
 
 
Naomi
Elite Veteran
Location: Ontario, Canada

BIGRCR,
Sorry didn't meant to step on your toes, but if you looked at how most glow engines carb. except for the IMZ50, or Foxy from vario, and of course the Gasser carburetors throat, they are sticking out right into the open areas, where as others concealed more into the fan shrouds, lessened the chances of drawing up debris into the carb.

JR IMZ




Gasser Carbs placement




Environment is another important factor that filter would be highly recommended , such as dusty desert area, even for glow engines as well. Due to the fact that the placement of carburetors.. I would rather playing safe to put a filter on than risking ruining or worse crashed a gasser because of debris. Think of the carb as a JET turbine intake..

Naomi
08-30-2003 Over year old.
HOMEPAGE  
 
 
BIGRCR
Veteran
Location: Easley, South Carolina

Point taken and true! No offense taken. I did not really want to remove the air box but since I was doing some experimenting I did so. So far, I don't think is has been much of an issue as the chopper has the carb a good distance off of the ground and spends very little time actually on the ground. My thinking (maybe wrongly) has fallen along with the rest of the glow pilots that no cleaner is neccessary. If my flying field was not such plush grass, I beleive I would get nervous enough to put the air box cleaner back on. That's why it is still in my flight box for that trip to a dusty field.

Later,

BIGRCR- John Garst
08-30-2003 Over year old.
 
 
ELOSSAM
Veteran
Location: Es

The air filter reduces airflow to the carb due to its filtering function. To help it I suggested the idea of an air filter and a velocity stack working together and so did I.
Have no bench datas but at least it runs as good as without air filter.
Elossam


08-31-2003 Over year old.
HOMEPAGE  
 
 
rtrickyjr
Veteran
Location: Drumore, PA (SW of Quarryville)

Elossam

can you give me details on what you're using to get the stack/filter setup to work for you? I like it, thanks, Rick


-Rick-
08-31-2003 Over year old.
 
 
Malorie
Elite Veteran
Location: Paw squared, MI

I have switched back and forth between the stack and the filter on my G26. I really haven't noticed any change worth mention. I am currently leaning toward the filter for reduced noise, less crud in the carb, and smoother airflow into the carb. I have noticed with a stack, in some of the flight attitudes the mixture changes due to differences in airfpressure into the carb. I notice no such thing while running the stock snuffbox type air filter.

Life's a journey, NOT a destination.
08-31-2003 Over year old.
 
 
rtrickyjr
Veteran
Location: Drumore, PA (SW of Quarryville)

Malorie

What filter are you using on the G26? Thinking of getting one, thanks


-Rick-
08-31-2003 Over year old.
 
 
SteveH
rrProfessor
Location: Texas

Everyone's input is/has been appreciated in this thread, however I've yet to see any answers to my second question, Do you have any supporting gasser heli data other than "gut feel"?

Thanks again for your inputs.

SteveH
Magnum Fuel
AMA76186
08-31-2003 Over year old.
 
 
ELOSSAM
Veteran
Location: Es

Malorie
I have not calculate any number for it.
I took the inner diameter of the filter and the biggest one of the carb. With these two datas my lather friend build for me a intake making the desired reduction between diameters. What is really important here is to have the bigger diameter you can on the air filter and a smmoth transittion to the big carb diameter. Doing it so you will avoid turbulences before the carb and the airflow will be more laminar. A big filter allows the airflow to pass "slowly" through it in benefit of the filtering function. Then the diameter reduction will accelerate the airflow helping the air-fuel mix inside the carb.
As I told above, I have no bench datas but using this device I need to rich the needles about 1+3/4 H and L to start having a nice plug colour, therefore my engine is able to run with more fuel than the others helping also to self refresh (see Bilme method). What differs with Bilme system is the fact that I don´t need to reduce the oil amount (I´m currently using 4%) and the mix must be quite perfect because the plug has not the less residue .
May be I´ve accidentally found the right velocity stack meassures but I think any simmilar system will help.
The stranger form of the external side of the velocity stack fits exactly inside the air filter and fix it without any other help.
Let me know if you need a closer view of it.
Elossam
08-31-2003 Over year old.
HOMEPAGE  
 
 
Naomi
Elite Veteran
Location: Ontario, Canada

Elossam. , How do you secure that Filter to the velocity stack? Curious mind wants to know.

Naomi
08-31-2003 Over year old.
HOMEPAGE  
 
 
Ooppss
Senior Heliman
Location: At the field flying !!

Sorry, but what is "Velocity Stacks" ??

Naomi: Do you have a part no on that K&N filter in the picture of your heli ???
08-31-2003 Over year old.
 
 
Naomi
Elite Veteran
Location: Ontario, Canada

Ooppss.. that's not the K&N in that purple frame benzin.. just the stock plastic filter box..

K&N Filter with choke part #1022/5


Velocity stack including gasket Part #1922/13


Naomi
08-31-2003 Over year old.
HOMEPAGE  
 
 
Al Magaloff
rrMaster
Location: 12,199 Posts- Enough Time Wasted. See Ya!

A velocity stack is the bell shaped inlet to the carb. Air speeds up( increases in velocity) as it comes in and is forced to a smaller diameter.
09-01-2003 Over year old.
 
 
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Gasser Model RC Helicopters > Velocity Stacks?
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