SR71A Help??
 

Hi Guys

I have a friend who's uncle was in the Hobby about 10 years ago. Recently he passed away and left his Estate to my buddy. Upon helping him sort out many items in his basement I discovered a SR71A.

As luck would have it the plans were there as well as the Drog Chute. There were what looks like Ram Tec 5 inch Fans minus motors. The landing Gear is Mechanical and seem to work while the Servos are shot.

My friend gave me the SR71A since he knows I'm an RC Junkie and if anyone can fix it I will find a way.

I made a Phone call to Charlie Lines up in NY he used to be a very Familiar with the Yellow Kit as Lance Campbell is. This Model Measures 105 inches long and 57 inches wide. Empty weight Minus Motors is 20Lbs. It's all wood and glass many wood formers. This is not the Yellow Kit.

Enclosing some Photos my question is it worth making her ready for flight?

I would need 2 DF motors, 10 servos and misc hardware.

Let me know what you think.

The Hatches were removed so I could see whats inside them but there all intact.

Ian

RE: SR721A Help??
 

There WAS an all wood kit, I had one, for the life of me, cannot remember the manufacturer.
By all means, yes, fly the sucka! You have nothing to lose except a week of evenings installing all the gear.

RE: SR721A Help??
 

Fly it , nothing to loose for sure. If the DF don't get it up go turbines!!! You may try to get a copy of the Yellow manual anyway. I'm sure it would help out a lot in trying to figure out CG and control throws. Best of Luck !!!!

RE: SR721A Help??
 

Flyjets,

Man, that is like finding the proverbial 63 Corvette that has been stored in some little old ladies garage for the last forty years...well, maybe not to that extreme!!! I say find a local museum for it and let the man's work live on through the eyes of others. There is a reason that you don't see them at many event's....the few Yellow versions I have seen fly were rekitted in short order. Sure, everyone would love too see an R/C version of the SR-71 fly, but the odds of it's success from takeoff to a controlled landing are not in your favor despite your flying ability. Some things are just best left alone for obvious reasons. As an R/C modeler, you have found an R/C treasure...treat it as such.

RE: SR721A Help??
 

mugenkidd EASYTIGER CountryBoy

Many years ago I was Flying a Merlin SW4a full size with a fellow Modeler in the CoPilots seat. On Take Off the right engine failed of course we were heavy and the engine caused the SW4 to yaw a bit but it turned out well. The First Officer and I have been good friends since that day kinda like a bonding experience. At Dinner that night he showed me Photos of his 1st SR71A.

I'm telling you this because this fellow also was one of the earliest RC Pilots of both the SR71 from Yellow and the one I have in my shop.
His advice is the same as yours restore it and donate it. I have to tell U she sure is a beauty with about 3 weeks work she would be pristine.

My small workshop is jammed packed just finishing a Dave Patrick Edge 540T
Next to Go but will be a planned 2 Month Great Planes Matt Chapman Cap580 1/3rd scale
Then the SR71A just can't decide if I should replace the servos and make her functional.

Thanks For ur Input

Ian

RE: SR721A Help??
 

No offense intended, really, but...
I think the SR71 flies fine, many have been flown in various sizes, most recently, a giant one in Germany, all balsa like this one, flew like a charm.
As far as collector value goes...this has NONE. Built up models, unless they are museum quality(this one looks nice, but FAR from museum quality) have very little value. THe best hope is that some resturaunt will want to hang it from the ceiling.

RE: SR721A Help??
 

Unless the servos are 70's kraft ones with the old carbon pots, there is no reason why they are not still useable, unless there are some broken gears from storage and handling. Go hook up your servo driver and see. There is NO logical reason to replace them just because they are old.
The fuel tanks, though, should be removed and replumbed. Not a big deal.
You need two OS 91 df engines...and two pipes. Don't forget the pipes. So it IS somethign of an investment needed, money wise. Twin turbines? That's a whole nother ball of wax.
You should fly the thing! All you need to do is keep both engines running, and all should be cool!
Don't beleive all the "it won't fly" jive about the SR71, there is nothign wrong with the configuration, some crashed, sure, but it's not unflyable. They said the same thing about the 117, yet it flies fine, in spite of the experts loudly proclaiming it would not.

Anybody remember the name of this kit? It's on the tip of my tongue...

RE: SR721A Help??
 

This maybe just me, but I'd rather die in flames and glory, than rot in a nursing home! ;) I say let the little blackbird have wind under its wings, at least once.

RE: SR721A Help??
 

Yeeeessss!

That thing is dying to get airborne, you can tell.
ONE flight would be enough. Try to picture it doing a low pass. A twin DF SR71? That's what modelling is all about.

What's that Beatles song? Blackbird FLIES! Not "blackbird gathers dust in the garage..."

RE: SR721A Help??
 

:D I'm going to say, 'go for it' too. [sm=thumbup.gif]

"Tis better to have loved and lost than never to have loved at all." But I, like the others above, see no reason why it would be 'lost' :D

RE: SR721A Help??
 

Let me translate what Dave said from English to American:
"Fire that sucker UP!"

RE: SR721A Help??
 

:D

RE: SR721A Help??
 

LOL!!! Easytiger you crack me up man :D:D:D Keep us updated Flyjets.

RE: SR721A Help??
 

Better put some lights on it.

RE: SR721A Help??
 

How cool would THAT be? No need to get fancy, just a glow stick taped to each wingtip, and maybe one rubberbanded onto the snout.

Twin ducted fan SR71 at night. How cool would THAT be?

Seriously, though...this model is a chance to fly something totally, completely outrageous, with a good chance of perfect success, without committing a lot of time or money into it. I think the original builder would be honored if you took it aloft.

RE: SR721A Help??
 

Dennis Crooks used to put on a real nice demonstration flight with his YA Blackbird.

RE: SR721A Help??
 

Dont forget to get us some video of that baby.

RE: SR721A Help??
 

No, it's not worth making airworthy again, so you should put it in a box and send it to me so I can make it airworth.... err... make it a display model?

:P

Well, seeing as it's an SR-71, I say it's 100% worth getting airworthy, regardless of the price. I say, find some new servos, dig through eBay for any replacement parts/old broken kits/new neverbuilt kits, and rebuild that sucker.

Best of luck with getting that black beauty back up & running, even if you don't fly it.


- Camel.
P.s. Don't listen to these chuckleheads... Don't donate it! Keep it! (unless you're donating it to me). LOL :P

RE: SR721A Help??
 

Ian,

Straight from the horses mouth as high lighted above. I think the gent knew a thing or two...my two cent's, take his advice !!!

Easytiger, no offense taken. However, to state that it is only fitting for a restaurant doesn't wash. I'm sure there are several Museum Curators that wouldn't mind having it hanging from their ceiling at all. It's in Ian's hands now...only he can make the final judgement call.

As for the designer, does the name G. Bertella ring a bell ?

RE: SR721A Help??
 

Alright

The Project that wasn't suppose to progress appears to be moving forward.

I need everyones help again I'm enclosing a series of Photos showing the original Fans.
Some research leads me to think they are called Turbax III Fan Unit am I right.

As luck once again has it a friend that runs a LHS has this other Fan and a in need of repair OS91 DF
Looking at this fan I think it's a Ram Tec is this correct?

Now several questions The Ram Tec has many more Compressor Blades. This indicates it's more efficient at lower RPM guessing in the 20K range.
The Turbax fan looks similar to some WeMoTec Mini Fan indicating high RPM would be best say 40K but I doubt a gas engine can turn those RPMs it's probably just an old design.

The OS91 needs a new Barrel and new Gaskets all around. It looks like a older engine.

Any incite you guys have I am all ears as I am not a Glow Ducted fan expert.

Ian

RE: SR721A Help??
 

Mmmm...I dunno, I deal with and donate a lot to a lot of museums, I think you would have a hard time with this particular model...meuseums get a lot of offers for this kind of stuff, because people can get a big write-off, but they have to turn most of this kind of stuff down because of storage issues...but who knows?

I doubt that it's a Bertella, because all of the Bertella planes I have seen split down the centerline of the fuselage horizontally for access...also, they are set up for six inch fans, a Bertella fan that is like the Byron. But I have not seen the Bertella SR71 specifically, so I can't say for sure.
I am 100% positive there was an all-wood blackbird in this size. I had the kit, I blanched at the amount of work involved, and sold it a few years ago. Just can't think of the name. Jet Age Models, maybe?

RE: SR721A Help??
 

You identified both of them correctly. The Turbax is not very efficient compared to the Ramtech or dynamax, it's really obsolete. It was not really made for a 91, more like a 65.
You can use the Ramtech fan, no problem, but stay away from the blown engine. A new piston and cylinder is $180. A new engine is $300 or so.
There are many bargains to be had on new or slightly used Ramtech or Dynamax OS91 setups, they are always trading hands here and on ebay and such. I would hold out for $400 for each setup, with the pipe, for new or near new. I would NOT want to be mussing with a rebuilt engine of unknown origin on a twin with the engines way far apart like that, just to save a little bit of money. If a piston and cylinder was only $50, you might be saving a lot, but they aren't!

RE: SR721A Help??
 

EasyTiger

It's so tempting to install two Ram 1000 into her but until I cut into the Fuselage and see the condition of the Glue joins and Formers I am just going to look at Ducted Fan motors.
I agree often on E bay there are guys selling 2 motors and Fans.

I noticed the RamTec has a pressure fitting behind the compressor to pressurize the fuel Tank. Is the BVM stuff much superior to this?

Ian

RE: SR721A Help??
 

Going turbine is such a different story, two 1000s would mean digital servos all around, stronger landing gear, all that stuff...totally different project. Better off starting with a new model.
The pitot fitting for the Ramtech is not ramtech specific, any of the fans can use either pitot or pipe pressure, and it's one of those "two schools of thought" things, I always used pipe pressure, but I'm beginnign to think pitot pressure is better because if the pipe comes out, you engine will still run. Just saw a freind do that the other day with a JHH hawk...something came off the airplane, I did not realize it was the entire pipe!
Is the BVM stuff that superior?
Hell, yes. The BVM fans and engines blow all the others away, by a country mile, more thrust, and much more reliable. It will be a little work adapting them Viojett or Viofan, because they have a slightly smaller diameter, but it would be worth it. There are bargains to be had on THEM, too.

RE: SR721A Help??
 

The fan with the 11 blade rotor is a Dynamax by Tom Cook at JMP. The pitot pressure works very well to pressurize the fuel system. Looks like you have JMP System II tuned pipes also. You can't do any better than what you have unless you go turbine. IMHO you won't pick up any performance by going BVM unless maybe you go with his latest fans and BVM .96s and if you're going to spend that much money, you might as well turbinize her. Dynamax fans have been flown in larger and heavier airframes than anything BVM powered.