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Tower 75, sullivan onboard glow

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Old 10-23-2007, 12:26 PM
  #1
jeffk464
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Default Tower 75, sullivan onboard glow

I have a tower 75 mounted horizontal with a bisson pitts muffler, it transitions well from idle to full throttle and will stay at full throttle all day long. The problem is when I cut back below appox 25% throttle in flight the engine often quits on me. This motor is in a top flight mustang that I have put a lot of work into and really dont want to loose it. I saw an add for the sullivan onboard glow system advertising no more flame outs. My question is do these things really work to help keep an engine from quiting in flight, and also with the pitts muffler should I go with a perry pump to insure adequate fuel pressure? Should I go for both solution or would one or the other probably fix my problem?
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Old 10-23-2007, 01:43 PM
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Default RE: Tower 75, sullivan onboard glow

I don't think an onboard glow driver is going to fix that. Mostly, the onboard glow is to help inverted 4 strokes idle better, or act as an igniter for starting (for engines totally enclosed without having to poke a hole in the cowl). The problem you are experiencing sounds like the low speed mixture is too lean, or it's underpropped. If it is more prominent in the air than on the ground, it's probably too lean. The weight and momentum of the airplane actually allow the prop to spin faster in the air (at level flight or in descent) because there is less resistance on the prop.
If you can run WOT till the tank goes empty, you have enough pressure. Unless the engine is on its last leg and all worn out, it doesn't take much pressure in the tank to feed the engine. The pressure in the fuel tank needs to be just barely more than atmospheric.
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Old 10-23-2007, 01:52 PM
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Default RE: Tower 75, sullivan onboard glow

Thanks for the help, I'm running a 13x6 apc which is the largest recomended but I'm using a 4" spinner. By the way, on the ground I get no flameouts.
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Old 10-23-2007, 10:42 PM
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Default RE: Tower 75, sullivan onboard glow

This is just a thought, but when your 'stang is on the ground the fuel tank is a lot lower than it is in level flight because of the way these plans sit nose high. When you hold the plane level or slightly nose down on the ground can you duplicate the inflight problem?

David
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Old 10-24-2007, 12:27 AM
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Default RE: Tower 75, sullivan onboard glow

I'll have to give that a try, havent attempted that yet.
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Old 10-24-2007, 10:16 AM
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Default RE: Tower 75, sullivan onboard glow

If this engine is adjusted (tuned) properly you houldn't have a problem. I would recomend getting the best engine person you know to give you a hand and tune this engine properly. I think the onboard glow will help with rich condions and inverted engines but not lean conditions as someone mentioned earlier. The onboard glow will help a Super Tiger 2300 run as I proved that to myself and others. But the problem with it (2300) was fuel loading up in the crankcase due to improper carburation or engine design. The Tower 75 isn't the same engine, it will run as well as an OS 61FX and has more power. One option you may want to try is use an older airplane such as a trainer or something that will glide well and break this engine in on it. The 75 does take a little break-in time to run reliably, but not much.
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Old 10-24-2007, 08:48 PM
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Default RE: Tower 75, sullivan onboard glow

I also have the st2300 .
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Old 10-27-2007, 08:25 AM
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Default RE: Tower 75, sullivan onboard glow

i hope your problem is not the same one that i had...................mine ran exactly like yours, and the idle mixture was set from way to rich to just about lean and everthing in between.
same thing, flameouts at around 1/3 throttle.....it got to the point of when i pulled the stick back and realized i had been at a particular spot on the throttle that i knew it was going to flameout everytime......the engine would not shut down even with the air blocked off to the carb..............turns out to be a bad fit between the crank/case, or leaking bearing, or both.
either way, i sent the engine back and got a credit to purchase something else.
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Old 10-27-2007, 07:01 PM
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Default RE: Tower 75, sullivan onboard glow

I can shut mine off with throttle cut on my transmitter, so it sounds like a different issue.
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Old 10-31-2007, 08:05 PM
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Default RE: Tower 75, sullivan onboard glow


Quote:
ORIGINAL: summerwind

i hope your problem is not the same one that i had...................mine ran exactly like yours, and the idle mixture was set from way to rich to just about lean and everthing in between.
same thing, flameouts at around 1/3 throttle.....it got to the point of when i pulled the stick back and realized i had been at a particular spot on the throttle that i knew it was going to flameout everytime......the engine would not shut down even with the air blocked off to the carb..............turns out to be a bad fit between the crank/case, or leaking bearing, or both.
either way, i sent the engine back and got a credit to purchase something else.
Summer,

Did they credit you your shipping for the original motor and shipping to send it back? I sent mine back for the same problem and they reported the crankcase was over bored and could not be repaired. The engine is backordered so they credited me the motor cost but I am out both shipping cost.
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