Flight of the rocket boosted SR-71 Blackbird - P. Gibeault

Old guys having a blast!!

Incredible, awesome, unbelievable.

I'm proud to have snagged one of Paul's RR-1's.

Love the Smoke !!!!

OOOOh, that had to bee a BLAST! Ya just can't beat the sound of twin Bees in sync. Paul, didn't you have a "build log" of that plane on another forum? Seems I remember a post where you indicated the toughest part was cutting off the inlet cones to make the motor mounts for the bees?

Marleysky wrote:OOOOh, that had to bee a BLAST!  Ya just can't beat the sound of twin Bees in sync.  Paul, didn't you have a "build log" of that plane on another forum? Seems I remember a post where you indicated the toughest part was cutting off the inlet cones to make the motor mounts for the bees?

Sadly, I did not do a build log on this airplane. (Or I can't seem to find any photos). Yes, cutting off the original pointed nose cones only showed I had to glue the plywood firewalls directly onto foam. I wasn't sure if that would hold so I ended up wrapping the plywood plates with carbon cloth giving more bonding area. Seems to have done the trick. And, as usual with me, I'm in such a hurry building (leaving things to the end) I aligned the firewalls by eyeball erring on a bit of out thrust if anything. C/L models can still fly OK with some misalignments thank goodness! Other than ordering my replacement decals too late (the originals were so old they just fell off), it came out the way I wanted. (The scale judge did correctly deduct some points over the missing decals) I didn't know the finish was not fuel proof either, so some black paint has come off.
If I had to "improve" anything, I'd like to:
1. Spray on a satin clear coat for fuel proofing.
2. Make up the motors from all black anodized parts.
3. Consider the use of a deployable drag chute for landing.
4. Find a rocket motor with a longer burn time and more power (if possible).

I have 2 more Blackbird kits, but doubt if I'll ever build them. Such a model is (to me) not a serious scale contender, but more of a fun scale "Show Model". I'm really happy I got that dream off my "bucket list". It was a blast!

I had to watch it again which prompts some questions.

Who was the pilot and ground crew? Incredible job all around.

Did both engines cut off at the same time, or did you have some sort of joined cutoff?  

How long were the lines and what material?

How in the world did the pilot keep up when the rocket ignited?

I was standing about 10 feet to the right of the cameraman when this flew. The rocket was much louder in person than the video shows.

The Jumpy Mark

rsv1cox wrote:I had to watch it again which prompts some questions.

Who was the pilot and ground crew? Incredible job all around.

Did both engines cut off at the same time, or did you have some sort of joined cutoff?  

How long were the lines and what material?

How in the world did the pilot keep up when the rocket ignited?

I was the pilot in the red shirt. My ground crew was Ken Burdick & a really helpful modeler named Tim Wescott. Tim, after not smoking for ~ 25 yrs, lit up a cigarette, just so I could get the flight in. (my barbecue lighter had just failed) After both engines were running he lit the calibrated burn fuse at which point the model was released. Once lit, Ken couldn't wait to let go of the model! I can't remember exactly, but I think the lines were either .012" dia. X 35' long braided steel OR possibly .010" X 42' solid music wire. I do know the drag is pretty close to the the same for both. As a C/L speed pilot, this SR-71 model is relatively slow in comparison (even though it LOOKS fast). If you listen carefully, you'll note when one engine quit first & the other kept going for a few more laps. Both engines use the Cox 8cc tank and the engines quit when they run out of fuel. Ideally the outboard engine should quit first to prevent the possibility of the lines going slack with just the one outboard engine running. For insurance safety, I positioned the leadout boom further aft than necessary. This causes the model to fly yawed to the outside of the circle at all times. This also slowed the model down somewhat in flight (but I traded off more line tension for less speed) to assure I'd get the flight in.

Paulgibeault wrote:
a really helpful modeler (whose name I forget).

Tim Wescott?

Yeah if you crank up the volume it makes a unique blast from the rocket power , I bet Mark did jump a bit when she took off .

batjac wrote:

Paulgibeault wrote:
a really helpful modeler (whose name I forget).

Tim Wescott?

 Yes, that's him!

Hi Paul, Is that model a modified Estes model rocket kit? Estes had a 19 inch (1/20 scale?) version. There are a few on eBay, but they're expensive. There's currently one (un-built but open package) for $90 in Florida (USA).

It seems that Estes had more than one kit/item/part-number for it.






Either way.. it's quite exciting to watch your flight! A version with twin Jetex/Jet-X engines would be interesting.. but probably not powerful enough for U-Control.

Roddie:

Nope, my 35" long SR-71 comes from a Hobby Labs kit. I bought mine when eBay first came out & bought 3 kits at that time. Seems they weren't particularly cheap, (~$150) but I really (thought) I had great plans for them at the time. I had envisioned E ducted fans as looking very cool whilst still being possibly able to maintain the pointy engine noses.  Seeing several SR-71's crashed on You Tube videos, I thought I'd need more than one until my dream model was perfected. Turns out I didn't need the other two kits as my first try flew perfectly right off the board.
p.s.
Oh, and my first rocket engine test fire onboard my SR-71 was with an Estes E size motor, which fit the mounting tube OK. All went well for the initial test fire until ~ about three seconds then BOOM! The secondary parachute charge lit off and fired the entire motor across my driveway like a shotgun had gone off!  Of course with no nose cone to blow off (in a fully enclosed tube) it had no place to go but out the back end. I quickly retrieved the spent motor casing, closed my garage door & disappeared fearing a neighbor might have complained about a gun being fired...

Note: For flight purposes I used the recommended high power composite Aerotech motor.

Thank you for the clarification Paul. Now that I think a bit more about it.. 1/2A engines would be a bit much for a 19" length "Blackbird"..  Gee....  maybe twin Jetex motors would work for an Estes 19" kit for a free-flight application. "Quest" model rockets offers an SR71 kit for its "Micro Maxx" engines which are approx. the size of a firecracker.. and are equivalent to a 1/8A power model rocket engine.

You can get a 6pk (w/igniters) on special for $5.99 here.. (beware.. there is an ejection-charge to be considered)

https://bellevillehobby.com/product/quest-micro-maxx-model-rocket-engines-with-mmx-g2-igniters-6-pack/?gclid=EAIaIQobChMI5cOnxtD79gIVS8qzCh3vWAd5EAQYASABEgKqL_D_BwE

Please excuse the model-rocketry stuff that I bring.. but it's more based on my love for the Lockheed SR-71. It's always been one of my favorites.

Nice flight Paul.  Always a challenge to get two Bees running at once.  I made a Bee twin as a kid that lasted about a day because of the reedy problems.  I suppose it was fun though, whether I liked it or not at the time.  Alan Feil

aspeed wrote:Nice flight Paul.  Always a challenge to get two Bees running at once.  I made a Bee twin as a kid that lasted about a day because of the reedy problems.  I suppose it was fun though, whether I liked it or not at the time.  Alan Feil

Thanks Alan!  I was lucky to have a good scale buddy Orin Humphries as a mentor. He very successfully campaigned a profile A-12 in 1/2A Scale for many years. Once I saw the Hobby Lab kit, I thought I could perhaps one up him with a full bodied SR-71. I really liked the idea of a rocket booster even though I had no idea of how to fire it. The real incentive boost came when Orin told me a Cox twin would be enough trouble & to forget about the rocket. So of course, I just had to try it!
I did however build two high powered mylar reed equipped mouse race engines fitted with TeeDee .051 piston/cylinder assemblies, burning Sig 35% nitro fuel...After all a proper SR-71 has to SOUND fast too!
Cheers,

Paul

roddie wrote:Thank you for the clarification Paul. Now that I think a bit more about it.. 1/2A engines would be a bit much for a 19" length "Blackbird"

Please excuse the model-rocketry stuff that I bring.. but it's more based on my love for the Lockheed SR-71. It's always been one of my favorites.

Lot's of great pictures and stories:
https://www.facebook.com/LindaSheffieldMiller/

Marleysky wrote:

roddie wrote:Thank you for the clarification Paul. Now that I think a bit more about it.. 1/2A engines would be a bit much for a 19" length "Blackbird"

Please excuse the model-rocketry stuff that I bring.. but it's more based on my love for the Lockheed SR-71. It's always been one of my favorites.

Lot's of great pictures and stories:
https://www.facebook.com/LindaSheffieldMiller/

I'm surprised that we haven't seen Jeff Bezos' creation in a similar ad.. but I suppose he's done enough in the aerospace arena lately..