digitech

My Feedback: (10)

we also sell to military , the weird thing is we needed to comply to iso certifications.
they play it safe , i dont think the us gouverment will agree with those lose canon thoughts i think.
but i have been wrong before

Warbirdguy

I believe that if the theory is there and valid, which it seems there is some validity to it, then it is just a matter of time before its tried. I can just imagine maybe 20 years ago when some jet jocky who was bored with the glow duct fan engine, said " Hey, wouldnt it be cool to have a true turbine engine to fly with" and then hear everyone in the hobby including all the educated degree holding engineers spend countless hours lobbying for why it wouldnt work. Now, 20 years later, duct fans are a laughable thing of the past. Only brought out like Old Skool hotrod shows for everyone to look at and admire that they even worked at all.

My point to all of this is: Its something new and against the norm. No one likes change that are comfortable with the proven. My opinion, and its just that, is to be safe, use a controlled enviroment, and give it a try Inagomontoya sounds like he has the experience and education to make a valid point and the enviroment to test it, so I say do it. Maybe in another 20 years ( If we survive 2012 lol ) we will all be looking back at the old propane start turbines and bringing them out like OLD SKOOL cars at a car show LOL.

Good luck man...Id be at your side in that bunker cheering you on!

Warbirdguy

EGRUNE

My Feedback: (10)

First I think Mr. Ignacio Montoyavich (Or whatever his name is) started out wrong,,,,But Wow!, some of you jet guy's have lost your minds......EASY NOW

A10FLYR

My Feedback: (1)

He simply asked a question.......and got a typical *old* JPO reaction!

Randy M.

My Feedback: (38)

Well this thread could have started off better. Instead of starting out like you did, you could have stated a little background and a little more info as to what you were trying to do. You have revealed information later in the thread that would have been useful earlier. Instead, you came off as a pompuss ***** Mr. know it all, money is no object, disposable, insured by U.S. Govt. etc.
A better start would have something like- Hello guys, I'm a rocket scientist (there are several here), I'm working on a project that could save taxpayers millions- and so-on. The attitude at the beginning just rubbed a few of us wrong. I apologize for my somewhat politcal statement ealier.
Good luck to you.
Randy

cdaubs

My Feedback: (6)

WOW!! You sound like you know it all, why bother us with your questions? We are but simple mortals. Try it and when your plane blows up, you'll have your answer!

rjbob

My Feedback: (8)

If a vehicle is already doing .5 Mach, the turbine can already be at operating rpm before the start sequence. If the fuel is passed through a heater before injection into the combustion chamber and the igniter is the "spark" type, I believe the turbine start time would be extremely minimal...without needing propane or silane.

u4eake

I'm without words for some of the reactions seen here. Partly why I didn't suggest this forum to you back on rcgroups Inigo. There's good stuff here and much interaction, but you have to put on your filters :-)
Topicstarter actually DID introduce himself nicely, but on rcgroups :http://www.rcgroups.com/forums/showthread.php?t=1234418
Iexplained a little about our modelturbines to him there, but I quickly reached the edge of my limited knowledge, which doens't mean I'm not willing to think along with him. Thinking outside the box is fun ! (and without it birds would still have the skies for themselves)

I don't think the solid combustionproducts of silane will be a big problem (keeping a mind the 15min life expectancy) if they stay small particles and don't clutter together (which I don't expect them to do). I have sucked up dust in my turbine before (when landing and hitting a pile of dirt from a mole) I gues many flying in the desert have ingested loads of sand and are still running after many hours (all be it with sanded components).

I guess thermal expansion vs clearances and fadec (ecu) control will be the main challenges. How about ditching the ecu and controlling the fuelpump manually ? What would be interesting to know is the RPM the turbine will 'freewheel' at when put in a mach 0.4 free airstream. You could then ignite with silane and start the pump at the 'normal' pumpvoltage for that RPM. Wouldn't this get his turbine going ? After that a timed ramp up to the pump voltage at max power (say 5 second acceleration time) and you're going at full power without all the safety and fool proof features in the fadec slowing things down. Fast startup, but little guarantee on a good start.

Lubrication of bearings is also something I have thought about. We mix 5% of oil in our kerosine and spray a little of that mixture on the bearings to lubricate them. I guess you could just do with a shot of oil into the bearings before flight and hopefully they'll last the 15 mins (I guess they will unless someone has other experiences ?)

I hope you keep us informed about how it turns out if you go ahead with it !

Regards,
U4eake

rjbob

My Feedback: (8)

Iñigo Montoya Mi nombre es Iñigo Montoya. Tú mataste a mi padre. Prepárate a morir...

From Princess Bride..."Hello. My name is Inigo Montoya. You killed my father. Prepare to die."

I wish the OP had explained himself/herself in a way that wouldn't have incited ridicule. I know that I wouldn't have been sarcastic...nor would, I believe, others.

rjbob

My Feedback: (8)

I would think that small particles could cause an almost instantaneous flame out.

Case in point...When Mount Redoubt erupted in Alaska in 1989, a 747 flew through an ash cloud. All hour engines flamed out immediately. The flight crew barely managed to get two of the engines started and the plane was able to limp into Anchorage International.

Using anything other than combustibles without solid effluents will, at the very least, be unreliable.

Gaspar

I don't see any problem, if the vehicle is flying at mach 0,3, there is a good amount of airflow against the compressor of the engine, it is already rotating at a good speed, then it is just matter of to add fuel and ignite it, with silane the engine could be running in very few seconds, basically depending on the rpm that the rotor is turning due at the airflow. I'm sure that 3-5 seconds is possible. Another thing is to manage the silane securely, it is very easy to do something very nasty with this gas.

Any of the shelf manual start ecu can do it without modification, except the control of the silane valve.

Gaspar

AndyAndrews

If you have such unlimited resources why the hell are you here? Buy a consumer turbine and trash one to find out. I don't understand why you are wasting your time here and I don't believe your working for the US government. Thats the biggest crock of BS, I've seen in these forums for awhile. For all we know, you are a terrorist try to figure out some sort of explosive delivery system.

I wouldn't give this guy any information what so ever. The US government doesn't come to RCU for information needed to run their experiments. This is total bunk guys.

Turbotronic

InigoMontoya,
The engines I am familiar with that can airstart inflight fall in these categories:
1> Low airspeed start, LOW altitude, uses a solid fuel gas generator ( rocket motor) to spin the Turbine and provide ignition heat, which you need a LOT of to start at high RPM (fast start) 3- 6 seconds startup time.
2> High speed, High altitude, ram air start, uses pyrotechnic OXYGEN generator to provide improved ignition. At this point the air is too thin to use normal ignition methods. Model turbine combustors will not work at these altitudes. 3 - 6second start time.
3> 1Kw Brushless motor starter spins to 50% RPM and use spark ignition and fuel atomisers. start time 2 - 3 seconds to FULL Power. Has been done with model turbines.

A model engine with any form of glowplug as ignition source will not work.
Your best bet is probably a pyrotechnic gas generator providing enough gas at a temperature low enough to not burn the combustor but provide enough gas volume.
If you are prepared to tinker it may not be a big mod to do. It may even work through the glowplug hole with a carefully designed fitting/nozzle. Who knows Nitrox may also work...

Our KS series engines start in 20 seconds to idle on kerosene, very fast compared to the 1 minute plus of more primitive systems but still too slow for your app.
BRG
Andre Baird

InigoMontoya

Possible, but not without difficulty. The booster has to attach somehow. In a traditional stacked system the turbine's nozzle would be blocked by the forward dome of the booster and/or the transition fairing. In a strap on configuration, yeah, the turbine could be spooling up in advance, but booster separation becomes more complicated.

InigoMontoya

Yes, this is the flavor I'm familiar with (as stated previously).

Ugh. You may very well be right but I'm trying to avoid pyro. Pyro means the entire development process for an ordnance item. That'd be more than my anticipated budget right there. The nice part of something like silane is that it's simply an industrial chemical. THAT is an easy thing to get through the process. Do an ORM. Write and SOP. Buy it. Slam dunk.

Had to google for nitrox. Not entirely sure I follow you. Are you saying to use it to spin up the turbine or as a combustion enhancement?

InigoMontoya

Because money doesn't flow until your ducks are in a row. Right now, we're still exploring feasibility. Ducks aren't in a row. Hell, we may have some birds but we aren't even sure that they're ducks.

Welcome to the 21st Century. The US government is well aware of the Internet and if you want to think outside of the box it's a great place to go. But don't take my word for it....

http://www.fas.org/spp/starwars/cong...fbk/index.html

Go to Chapter 5: Proliferation in the Information Age.

Look for the part where it talks about "Tryint in action"

See the part about the government guy who used the Internet to talk to a professor in Australia (second bullet under "Exploitation")? Voila, 3rd party corroboration that yes, the US Government does get technical expertise from the Internet (and that was 1997, I assure you that it's done nothing but accelerate).

Again, welcome to the 21st Century.

AndyAndrews

So your in the Navy. Is it the military's policy to openly discuss, on a public forum, ideas as it relates to our offensive/defensive weapon systems? I still find this whole thing very strange. It doesn't surprise me that the Navy would seek out information on the Internet. What does surprise me is, how you did it by being so vague on who you are, why you are seeking this information and then act surprised that anyone would be skeptical of your intentions.

Teachu2

My Feedback: (133)

Closest gathering of model jets would probably be Bakersfield or Fresno. Bakersfield had a huge gathering in March, 120+ pilots from all over, factory reps, etc. Email me and I'll do what I can to get you in contact with some of the jet modelers in the area.

Trent Combs, President
Bakersfield Airplane Radio Control Society
[email protected]

bjacobsen

My Feedback: (2)

Actually a lot of what this guy says makes sense, Ridgecrest where he says he's from is also home of the U.S. Navy aerial weapons test center at China Lake, and I am sure that they employ lots of civilian contract engineers as well as Navy engineers, and this could eventually have hobby applications for rc jets as well, it would be great to have an FAST emergency airborn start sequence for rc jet engines in the event of a flame out, albiet with more begnine (sp?) stuff than what he is contemplating.

InigoMontoya

Oh, this has nothing to do with weapons systems. If it did, there's no way in Hell I'd be discussing it here. We're interested in testing methodologies, nothing more. But to run a test you need a vehicle and as shocking as it may seem, it may very well be cheaper to cludge a "POS" vehicle together out of spare parts (so to speak) than it is to buy a mil-spec target and such (That's a lot of what I'm trying to figure out right now, but an engine that doesn't start in time isn't very useful so I'm trying to figure out if hobby turbines are an option or if I need to add a 0 to the engine budget.).

I've had it go both ways. I do most of my online research from my home account. Why? Because most of my tinkering is for side projects that don't officially exist (not black or anything; I mean really, they don't exist... my boss humors me and lets me tinker as it keeps my skills sharp and every now and then I actually find a diamond in the rough). Thus, the research gets done on my own time; not the government's. Anywho, own up to real ID with a "normal" email address and you'll get the same type of response that you gave me. I've seen it before. I'll see it again. I make my best guess as to how to approach any given group. Sometimes I win, this time I lost.

Teachu2

My Feedback: (133)

Lost how? You wanted help, and help has been offered.

Turbotronic

To start a turbine really fast you need a lot of expanding gas volume. This means that at low rpm/pressure the air/fuel mix does not burn at a high enough rate, hence the slow startup time. So adding an oxidiser like Nitrox will help this process along but temperature control will be an issue I think.
Only a suggestion.
I have experience with COTS and Turbine UAV projects. Best advice I can give you is add the 0 to your engine budget, it will be cheaper.

InigoMontoya

Lost from the "things got nasty" perspective.

Don't think for a moment that I haven't appreciated the constructive words.