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Old Sep 03, 2006, 02:34 PM
Retro
Iowa
Joined Mar 2006
30 Posts
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SR-71 Dual Turbines Axisymmetric Thrust

Would like to build a dual turbine SR-71 model. However I'm concerned about
axisymmetric thrust (off center) with the motors seperated so far at the aft end of the model. Wondering if anyone had suggestions has how to tune and synchronize (ECU) the two turbines, fuel system set-ups. Can one ECU handle both turbines, any manufacture better than others for this kind of set-up. How to handle control if one turbine stops running in flight.

Retro???
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Old Sep 04, 2006, 08:13 AM
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Puerto Rico
Joined Jun 2002
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I think jetcat ecu can can control twin turbines..
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Old Sep 04, 2006, 09:50 AM
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joeflier's Avatar
United States, MI, Plymouth
Joined Jan 2005
150 Posts
Some guys with twin turbines send both engines, ECU's, and pumps in for service to have the engines matched to each other. I suggest that you contact your manufacturer's service center to discuss.

Joe
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Old Sep 04, 2006, 06:42 PM
B58
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Joined Nov 2004
55 Posts
Sr

One ecu cannot control two turbines. All parameters are different for each individual engine. Not like just a throttle control on glow engines. You can build or buy a kit with a single center line thrust turbine hidden in the fuselage or mounted beneath. However, if you really want twin engines then you should not have a problem as long as you use two of the same type turbines. It also is very rare to have an engine fail unless you have a problem with your installation. I have only had one flameout, and that was on a first flight of an F-16 when I had an air bubble in the fuel line. Hope that helps. Bob Oh, the full scale SR-71 flys fairly well on one engine. I have observed that up close and personel.
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Old Oct 31, 2006, 10:00 PM
Aircrafting is noisey...what?!
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United States, CA, Long Beach
Joined Dec 2005
582 Posts
I agree with B58 the fuel pump would not be able to supply two engines and if it could with one out the fuel would continue to flow to the dead engine. I think the reciever gets a Y harness to the seperate ECU's.
The airliner guys swear by gyros on rudder for that senario and on ailerons for turbulance. Getting a matched pair sounds like good advise but you should be able to program their ramp and top RPM the same and get it right out of the box.
I have a twin turbine project started and I'm just learing about this too.
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Old Nov 03, 2006, 12:58 AM
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Yorba Linda Ca
Joined Apr 2004
237 Posts
I think given all of the challenges and problems associated with a twin turbine SR-71, asymetric thrust is WAY down the list. and I mean WAY down the list. Give me a break


EW
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Old Nov 04, 2006, 02:09 PM
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Joined Sep 2004
27 Posts
Twin turbine 30% Hunter.

We use twin Merlin 160 turbines in this 33% Hunter. 2 totally independant systems, the Fadec ecus are pretty good at keeping both engines in syncro. Video of test flight here
30% Hunter test flight (6 min 29 sec)


I would think that you could match both engines pretty close on the bench but as with fullsize there will still be small differences.

Rob.
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Old Aug 10, 2009, 10:32 PM
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German SR-71

I saw a video clip of an SR-71 being flown by man who sounded German. Does anyone have any information about that plane? A friend and I are try to figure out if it had two engines or on in the middle.
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Old Aug 12, 2009, 06:11 AM
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Estonia,Tartu
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329 Posts
http://www.mmrca.org/lance/sledframe.html ,you should contact this guy , he has an incredible sr-71 on the way ,he has bulidng it for several years , you can get the contact in the habu.org link
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Old Aug 12, 2009, 06:38 AM
TJK
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United States, PA, Harrisburg
Joined Feb 2001
120 Posts
The German SR-71 you most likely reference has a single turbine on the aircraft centerline, exhausting below the stinger at the tail.
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Old Aug 24, 2009, 01:27 AM
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VANCOUVER WA
Joined Aug 2008
10 Posts
contact sunset models ... he is the SR 71 guy he would know out of anyone
I believe he is finishing up an 18ft model of the black bird... i have a set of plans for the 9 ft scratch build version i would be more than happy to run off some copies ... i would have to charge what ever the copies cost of course
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Old Aug 24, 2009, 06:15 AM
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Estonia,Tartu
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Quote:
Originally Posted by Charged
http://www.mmrca.org/lance/sledframe.html ,you should contact this guy , he has an incredible sr-71 on the way ,he has bulidng it for several years , you can get the contact in the habu.org link

It has two turbines , he has molds of the whole fuselage and everyhting
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Old Sep 02, 2009, 05:41 PM
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http://www.fark.com/cgi/vidplayer.pl?IDLink=4464984

awesome
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