Latest and greatest timing and deck height?

[sahartman21]

Running at Littleton CO at 5000 ft. was an experience. I ended up lowering the head to about 16 or 17 thousandths. The timing setting measured between 191 and 193 thousandths for my engines.

I was using a 7.5 pitch prop.

[ceandra]

Jen Bozarth did a great job setting up my engine for altitude! I hear she is doing paint jobs as well now...

Chuck
11H

[Kurt Bozarth]

Chuck,

I am alittle concerned how you jumped ahead of me on her list...all I got was a “I will get to it when I can” postcard.

Great job on fast time! My phone app showed density altitude close to 8,500 ft most of the days.

Hank is probably still sleeping/recovering from weeks of work and little sleep getting everything ready for an awesome race!

Maybe the powers that be will ride the wave of momentum and have it at Jefco again soon, if not next year! (Sorry Hank!)

Kurt

[ceandra]

Kurt:

As Hank so strongly demonstrated, the needs of visitors superseded the needs of homies. Hank did not get to race while he was working hard to ensure our happiness.

Perhaps communicate with hugs rather than postcards? Worked for me!

She was aware of the high density altitude, and set my head clearance in the 14-15 thou range. She clearly did a lot of testing up to that point, and found that even 1 thou changes in head space made a difference. She had me set up at a fairly high deck height (going for 199 degrees, she uses a degree wheel). Others with lower deck height had success with more clearance, but most if not all dropped their heads a bit.

While density altitude did indeed reach 8500 feet, my good run was early Sunday morning, with clear (dry) skies, no wind, cool air, and Causey pushing me for 10 laps. Less than two hours later in a race that felt similar, the times had slowed considerably. After the storm pushed through and the air cooled, Tim Lime had a good race that had me worried, but both participants cut. Mike Langlois also had a good 4-man race, in which (fortunately for me) all four cut, would have been very close. In the flyoff, Mathew and Juan were very capable of beating me, but an early cut meant both pilots relaxed.

In racing, you have to do everything right, and then get lucky. Fortunately, with Jen's engine help, and a Harold Strega, I was in position when the conditions were perfect.

Chuck
11H

[rocket]

Leaking venturi and dirty shorts.
My first day out after battling the flu, in typical pylon mindset I'm heading to Markham to run motors. Welp, I have no idea where my motor test stand for 422 motors is. So, I run the motors in the planes. I'm running new topends i got from mike so I need a half dozen runs with the breakin prop. While holding the taylor mustangs I see raw fuel flowing from the cowl. Is is coming from the bearing? Donno, but after 4 runs I'm holding the plane and going to sit it back on the bench when it PUCH'S a stream of fuel and oil all over me. #WTF. after some inspections of the motor I find the culprit. The Venturi o ring is not seated in the front. Having dealt with this before and knowing the system used to hold the Venturi down I start thinking there's got to be a better way. After some wire twisting and trial fitting the motor I came up with a fix, albeit crude. I flew both planes today with zero xtra fuel leaking. Here's a narrative with pics for the dyslexic ones.
Here you can see the difference between the back hold down and the front.

Using stainless wire .032 I wrapped it around the bottom rung of the Venturi. Taking care to use only 3 twists to tighten it to the venturi. Leaving enough wire to wrap it around the bottom of the motor. Tighten down,
Pulling the front of the Venturi down tight.

Using a tool to tuck it into the the bearing ring.

Now, with another piece of wire, wrap it around the neck taking care to keep it below the oring

You can see the oring is even and won't leak. I did 8 flights today, same planes with zero added fuel from the motor bay.

Hope this helps RR

[splatt]

Mr. Brown,

The cover of the November MA magazine is fantastic, you represent the hobby well. Take a bow. I won't tell anyone you hold your engines together with bailing wire. The uninformed will not understand. I've rigged my share of with JB weld and tie wraps, but you offer a simplistic approach to what I see as a cracked inlet ?? Or is that just a chip ? Once these engines pass beneath the surface of the Earth some form of adjustment is needed afterward.

cracked.JPG (25.17 KiB) Viewed 2560 times

I had some short stroke quickie engines that were so bad I would have to re-wrap the carb with Teflon tape and tap it back into the inlet to run another heat, but I had a hard time finishing when little flakes of bearing were passing thru at the same time.

Thank you for sharing your information !

Jesse

[Hanknsd]

This is what the forum is all about, not some self serving, self promoting, whining and bickering place to blow smoke up your own a-s
The forum is starting to look like a Junior High school facebook page.
Let's get back to what it was set up for.
BTW, for what it's worth Lee & Rocket have done more for this hobby than anyone else I know. (Yes of course there are some others)
Hank D

[Kurt Bozarth]

Jen is working on a Q40 motor that seems fast, runs well, comes up on the pipe, and has overall great runs.

The problem is that when she checks the plug, the coils are distorted. I have heard that if the element is extending up and out of the plug, "the plug is seeking heat" and therefore we need to lower the head.....and if the glow plug element is distorted and pushed inside the glow plug, it "is hiding from heat" so we need to raise the head. Any comments regarding plug elements distorted IN versus distorted OUT? Jen would love to hear from those who have encountered this problem and how they fixed it on race day.

Kurt Bozarth

[KRProton]

Hi Kurt.

I dont have an answer, but a question: My question would be how does the color of the plug look in both of these cases? I suppose this would be another part of the puzzle needed to answer the question.

Tim Lampe

[Mr_McGlue]

Kurt,

I'm hesitant to answer since I'm the resident new guy but I had the same problem with a borrowed engine I was going to bring to the last race we were at. It was put together with various parts and was a pretty tight fit. It ran great once I got it started but was hard to turn over when cold. Ended up breaking the conrod a couple days before we left so decided not to use it.

Anyway..it would go 11 laps no problem and was fast. When I would check the plug the coil was an "innie" and messed up. It would still glow though. The color of the plug was a tad dark but not bad. Would turn the needle rich a bit but same result. Went through several plugs and finally raised the head .002 and that problem went away. The color would reflect the needle setting more accurately and speed was the same.

Now I was told to raise it that much and I guess it makes sense when you say the coil is retreating from the heat but wouldn't the plug be darker?

Not sure if that helps your resident mechanic or not. My useless .02 you can line the birdcage with

Robert

[rocket]

The only two cents that's usless is the two cents you don't give.

[Kurt Bozarth]

Now that I have sorted through the myriad of timing and deck height comments, I have a new question: where should I set my needle? 2 o’clock? 2:30? 5:00?

Kurt

[KRProton]

Hi Kurt.

I'm not providing a definitive answer here, just trying to contribute and further the conversation...

I speculate any expert who answers this is going to tell you to position the needle wherever necessary to a give the desired rpm. This position will change depending on all kinds of things particularly prop and weather conditions. I know you already know this, so maybe I'm missing something in your question.

Tim Lampe

[cbk07]

Now that I have sorted through the myriad of timing and deck height comments, I have a new question: where should I set my needle? 2 o’clock? 2:30? 5:00?

Kurt

Kurt,

You have to be very careful setting your engines using the clock hands method. It can get very confusing depending on what time zone you are in and even more so depending on whether you are in an area with or without daylight savings. If the race happens to fall on the weekend the time is changing, forget about it!

I have also heard that the difficult tuning phenomen known as “Muncie Air” actually is caused by the proximity of the field to the line separating the Eastern and Central time zones.

In an effort to simplify things I have started using the compass method. Simply peak your needle in the morning then open it until it is pointing exactly due East. Works every time. Most Phones have a compass these days, but I have also had decent results approximating based on the location of the sun. Before you know it, you will throwing away your Tach! When using the Compass Method, it is recommended that SAS users open their needle an additional half turn (or Due West). While this is not mandatory, it will help to level the playing field. This of course only applies to the guys actually using SAS, not the ones that sit around and write about it all day/night on the internet.

Hope this helps!! See you at a race soon

Craig

[cbk07]

Double