Duke Mordja
Well-Known Member
- Joined
- Jan 15, 2005
- Messages
- 759
What are the characteristics of having too small or too large of a stinger diameter on a 67 or 80 engine? What to look for??
Thanks in advance,
Thanks in advance,
Hi Mark,John,
I am ready to start testing "flawless and durable".
When are you going to have some free time?
Duke,
I think the .415" stinger diameter is going to be fine for your set up.
I may have a better set of propellers than your H-48's?
It is important to find the right set of propellers that make the boat
more responsive for heat racing. Duke give me a call when you have time.
Thanks For Reading Fellas,
Mark Sholund
231-590-3023
Jim, the pipe volume that you mention, is it measured from the exhaust port to the end of the stinger or is it the volume of just the coned sections?Stinger length & stinger inside diameter both will effect the engine's operating temperature. However, increases or decreases in diameter will have a much more pronounced effect on the engine's operating temperature than increases or decreases in stinger length. In order for any tuned pipe to be able to give a high boost pressure, without a heat problem, the tuned pipe being used "MUST" have an adequate volume compared to the displacement of the engine. A factor of approximately 26+ times for nitro engines to approximately 32+ times for gas engines will allow the use of longer, smaller internal diameter stingers.
Consider the fact that the stingers I use on my 26 cc QD engines are .4062" ID X 5.5" in length. The gas engine's operating temperature is approximately twice what would be found in a nitro engine of the same size. I use a toroidal head with a volume of less than 1 cc & a deck clearance of 002". The measured tuned pipe internal pressure is 120" of water or 4.336 psi. at WOT.
Jim Allen
Tim,Jim, the pipe volume that you mention, is it measured from the exhaust port to the end of the stinger or is it the volume of just the coned sections?Stinger length & stinger inside diameter both will effect the engine's operating temperature. However, increases or decreases in diameter will have a much more pronounced effect on the engine's operating temperature than increases or decreases in stinger length. In order for any tuned pipe to be able to give a high boost pressure, without a heat problem, the tuned pipe being used "MUST" have an adequate volume compared to the displacement of the engine. A factor of approximately 26+ times for nitro engines to approximately 32+ times for gas engines will allow the use of longer, smaller internal diameter stingers.
Consider the fact that the stingers I use on my 26 cc QD engines are .4062" ID X 5.5" in length. The gas engine's operating temperature is approximately twice what would be found in a nitro engine of the same size. I use a toroidal head with a volume of less than 1 cc & a deck clearance of 002". The measured tuned pipe internal pressure is 120" of water or 4.336 psi. at WOT.
Jim Allen
Marty,Jim Allen are you the Jim Allen RC Pylon racer in Dubai
just reading Model Aviation
marty
Marty,Jim Allen are you the Jim Allen RC Pylon racer in Dubai
just reading Model Aviation
marty
Marty,Jim Allen are you the Jim Allen RC Pylon racer in Dubai
just reading Model Aviation
marty
Tim,Jim, the pipe volume that you mention, is it measured from the exhaust port to the end of the stinger or is it the volume of just the coned sections?Stinger length & stinger inside diameter both will effect the engine's operating temperature. However, increases or decreases in diameter will have a much more pronounced effect on the engine's operating temperature than increases or decreases in stinger length. In order for any tuned pipe to be able to give a high boost pressure, without a heat problem, the tuned pipe being used "MUST" have an adequate volume compared to the displacement of the engine. A factor of approximately 26+ times for nitro engines to approximately 32+ times for gas engines will allow the use of longer, smaller internal diameter stingers.
Consider the fact that the stingers I use on my 26 cc QD engines are .4062" ID X 5.5" in length. The gas engine's operating temperature is approximately twice what would be found in a nitro engine of the same size. I use a toroidal head with a volume of less than 1 cc & a deck clearance of 002". The measured tuned pipe internal pressure is 120" of water or 4.336 psi. at WOT.
Jim Allen
Measure from the exhaust port to the end of the stinger. Also keep in mind that the area from the exhaust port window to the tuned pipes header should decrease. This part of the tuned pipe should also be pointed in a downward direction, approximately 10* to 15*. The beginning of the tuned pipes header should not be straight, as is found on all of our toy engine stuff, but tapered also, approximately 2* to 3*. Remember, any device that is similar to a tuned pipe will work to some extent. A good ball park figure to look for when calculating the stingers length would be, it's length should be 13.5+ times it's ID, if the pipes volume is the correct amount.
I measured many tuned pipe internal pressures, while the engine is operating, with a Wika water gauge, capable of reading 0 to 200 inches of water in 5 inch increments. Very Interesting stuff found when comparing a good & not so good chamber????
JA
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