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Engine basics => Engine set up tips => Topic started by: Larry Wong on February 27, 2022, 01:47:31 PM
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It's been awhile I have flown a IC plane and I seam to forget what the pipe length is ? (17 1 1/2" is what I have but I seam to run out of fuel on 5 oz tank? do I need to go to 5 1/2 oz? right now I get as far as the clover? ???
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It's been awhile I have flown a IC plane and I seam to forget what the pipe length is ? (17 1 1/2" is what I have but I seam to run out of fuel on 5 oz tank? do I need to go to 5 1/2 oz? right now I get as far as the clover? ???
Depends on the rest of the setup, what venturi and prop? 17.5 is definitely not a setup I have ever had any success with - too long for the "peak it out with 12-4" run that we started with, and too short for the Paul Walker system.
Brett
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I thought the RST 6 ounce tank was the standard size for 40 piped planes?
That is what I used with my PA40.
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I thought the RST 6 ounce tank was the standard size for 40 piped planes?
That is what I used with my PA40.
I have never run anywhere near that amount of fuel in a 40VF. Some systems were as little as 4 1/4.
Brett
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I didn't say it used all 6, just that the RST6 was used. :)
4 ounce would be too small, not sure there was a 5.
Been quite a while, but pretty sure I was similar to that, fill the tank, then pull out a bit less than a full 2 ounce syringe.
In his case, perhaps the venturi is bigger than it needs to be?
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I didn't say it used all 6, just that the RST6 was used. :)
4 ounce would be too small, not sure there was a 5.
Been quite a while, but pretty sure I was similar to that, fill the tank, then pull out a bit less than a full 2 ounce syringe.
In his case, perhaps the venturi is bigger than it needs to be?
As mentioned, I need to know what sort of prop and venturi he is running.
Brett
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As mentioned, I need to know what sort of prop and venturi he is running.
Brett
. Brett I'm not sure of Venturi , but the prop is a Eather 12x4 3blade the engine lap times is 5.2 - 5.3 seams to run good , just seams to not have a long enough flight to finish pattern . launch RPM is about 10,500 peak and back off. will shorting the pipe or change fuel help I'm using 10% Powermaster with 1oz of Aero 1 added.
Or just a bigger tank?
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. Brett I'm not sure of Venturi , but the prop is a Eather 12x4 3blade the engine lap times is 5.2 - 5.3 seams to run good , just seams to not have a long enough flight to finish pattern . launch RPM is about 10,500 peak and back off. will shorting the pipe or change fuel help I'm using 10% Powermaster with 1oz of Aero 1 added.
Or just a bigger tank?
Eather 12x4 3blade?! That is a HUGE prop for a 40VF. Pauls system uses a Bolly 11.3-4.25 2-bladem which is like a toothpick compared to your prop.
If it is otherwise running OK, which seems to stretch credulity, get a bigger tank. I am not at all surprised that it is using a lot of fuel, even as hot as it must be running.
Brett
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Larry,
Suggest you check the Pipe Chart section to set your prop, pipe, rpm. Seems like you are loading it too much and need to look at the total set up. If the engine is heavily loaded it will burn more fuel. To check the venturi size you can use drill bits to get the inside diameter. Also need to know if the NVA position is modified and what size spraybar diameter.
Best, DennisT
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Larry,
Suggest you check the Pipe Chart section to set your prop, pipe, rpm. Seems like you are loading it too much and need to look at the total set up. If the engine is heavily loaded it will burn more fuel. To check the venturi size you can use drill bits to get the inside diameter. Also need to know if the NVA position is modified and what size spraybar diameter.
Best, DennisT
Well, sort of, we already know what setups work, the chart is a good starting point if you don't have a good system. I have a feeling that this is not a good system and that is VASTLY more prop than we ever found to be optimal. I might stop by Alameda some morning and see what we are dealing with here.
Brett
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Well, sort of, we already know what setups work, the chart is a good starting point if you don't have a good system. I have a feeling that this is not a good system and that is VASTLY more prop than we ever found to be optimal. I might stop by Alameda some morning and see what we are dealing with here.
Brett
. Thanks Brett Just let me know when. just a P.S is the Rojet 61 same size as VF-40 ?
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Eather 12x4 3blade?! That is a HUGE prop for a 40VF. Pauls system uses a Bolly 11.3-4.25 2-bladem which is like a toothpick compared to your prop.
If it is otherwise running OK, which seems to stretch credulity, get a bigger tank. I am not at all surprised that it is using a lot of fuel, even as hot as it must be running.
Brett
Yes, for sure, too much prop load. I liked the 12-4 3 blade UC BE prop on my PA .51/pipe. I cut the same prop to 11.5" for the Randy Aero AAC .46VF and pitched up the tips 1/4 to 1/2" in the last inch or two. I always look at high fuel consumption as a good thing, though. More fuel = more oil = runs cooler. Randy's pipe length chart is pinned at the top of this forum. H^^ Steve