[AR] Re: Igniter Popping Sound
- From: Rick Dickinson <rtd@xxxxxxxxxxxx>
- To: arocket@xxxxxxxxxxxxx
- Date: Fri, 31 Oct 2014 09:42:57 -0700
Wouldn't running the main engine leaner (1:1 instead of 1.3:1) result in more
heat, not less? I thought running fuel rich was a way to reduce temperatures,
not the other way around.
Cheers,
Rick Dickinson
On October 30, 2014 5:58:03 AM PDT, Graham Sortino
<dmarc-noreply@xxxxxxxxxxxxx> wrote:
>Thanks, I’m really excited I finally got this working.After going
>through this somewhat frustrating process I feel like I have a
>muchbetter sense of how the theoretical factors in producing ignition
>are appliedpractically. To answer your question, yes, for example on
>this test
>(http://wiki.fubarlabs.org/fubarwiki/GOX-Ethanol-Igniter-v2.ashx#CABE-AF-BI:_Test_E_Best_So_Far_6)I
>thought the mixture ratio was about 1.5:1 but in reality it was only
>about 0.9:1. What I’m still not sure about though is why it wouldstill
>light sometimes at 0.9:1 even though that is a fairly lean mixture
>ratio.I think it could have something to do with the weather. Maybe I
>tested on a hotday one time and it worked and then a cooler day another
>time and it did not.Or maybe the igniter was already heated enough from
>prior tests so it did a better job of atomizingthe propellants. I’m
>not too bothered bythis, though, since I know that a ratio of 0.9:1 is
>too low. Generally, I’vebeen shooting for about a 1.3:1 for the igniter
>and I’ve been running about thesame for the main engine. I’d like to
>bring the main engine down a bit tosomething like 1:1 to see if it
>works so the main engine doesn’t run quite sohot. Also, I’ll try to
>get videos up by this weekend but Iwant to do a nice write-up first to
>summarize findings.
>
>On Thursday, October 30, 2014 7:23 AM, Robert Watzlavick
><rocket@xxxxxxxxxxxxxx> wrote:
>
>
> Graham,
>That is great news. I'm wondering if I didn't have similar issues
>since my igniter valve orifices are also 3/64" and the downstream
>orifice diameter is around 0.030. So I'm probably getting more
>pressure drop across the valve than I anticipated. So if I understand
>this correctly, the mixture is leaner then expected? Looking forward
>to seeing your videos.
>
> -Bob
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