Turbine inflight restart system
02-04-2016, 12:00 PM
#26
Been' flying a model without a UAT for some time now. I don't discredit them, but a properly laid out fuel installation with good venting makes them unnecessary. In my experience, I've had more problems induced by UAT's than due to lack of them.....all brands. Interestingly enough, your brand has been bullet proof. The only UAT I do have is a GBRJet.
Every one of my 10 plus jets has some form of UAT, BVM, PST, GBR, Intairco, MAP or home made ( JPX oil tank with centre pickups)
After aerobatics, ( and I fly my models like I was IN them) ALL these Tanks have SOME air in them, even with a felt pickup etc in the main tanks. That air would otherwise have gone to the engine and no doubt interrupted the fuel supply causing a flameout, avoided by the use o f a UAT of some form.
My tank installation is as geometrically and perfect as I can make it, and completely airtight.
02-04-2016, 01:06 PM
#27
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From my experience, the only way to prevent an air bubble in the UAT is to refrain from doing certain aerobatics. For instance, the initial low-speed down-line following a stall turn (hammerhead) with low fuel is almost bound to see air sucked into the UAT. It's probably the same for snap rolls and prolonged spins. If you enjoy flying military jets in scale fashion, maybe the only planes to do this kind of manoeuvring would be scale models of jet trainers eg Jet Provost etc.
02-04-2016, 02:24 PM
#28
Join Date: Jan 2011
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What a brilliant development and one I have long had in mind. The BS Viper in the RAF Jet Provost ( I instructed on it for 3 years, so a bit of experience) had an auto ignition system which was a ceramic glow plug so that in the event of a flameout due fuel starvation the engine immediately relit when fuel was restored. In 3 years on the training unit we never experienced any flameout problems that were not dealt with by this automatic system, simple, worked ! I believe that most flameouts on model jet engines are caused by fuel interruption such as bubbles etc.,
Airliner engine also also have auto ignition when flaps are extended or engine anti- ice is switched on by that requires HE igniters, not practical on model jets.
Great advance by Jets Munt , must add it to my truly delightful Merlin 100, a brilliant engine !
Airliner engine also also have auto ignition when flaps are extended or engine anti- ice is switched on by that requires HE igniters, not practical on model jets.
Great advance by Jets Munt , must add it to my truly delightful Merlin 100, a brilliant engine !
02-04-2016, 04:59 PM
#29
Been' flying a model without a UAT for some time now. I don't discredit them, but a properly laid out fuel installation with good venting makes them unnecessary. In my experience, I've had more problems induced by UAT's than due to lack of them.....all brands. Interestingly enough, your brand has been bullet proof. The only UAT I do have is a GBRJet.
02-05-2016, 10:08 AM
#32
From my experience, the only way to prevent an air bubble in the UAT is to refrain from doing certain aerobatics. For instance, the initial low-speed down-line following a stall turn (hammerhead) with low fuel is almost bound to see air sucked into the UAT. It's probably the same for snap rolls and prolonged spins. If you enjoy flying military jets in scale fashion, maybe the only planes to do this kind of manoeuvring would be scale models of jet trainers eg Jet Provost etc.
This is the primary purpose of the UAT: serve as a fuel buffer system that traps the air being sucked from the tank.
There is absolutely no problem in seeing some level of air in the air trap. What is important is to still have a good margin from the minimum fuel level at the end of the flight. This is also why it is so important to check the air trap level AFTER EACH FLIGHT.
02-05-2016, 01:48 PM
#34
Join Date: Nov 2005
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gunradd I was thinking of that exact video when reading all of this. The only way you could bypass any air problems is by using a bladder that compresses the fuel under pressure inside the tank.
