1/18 Scale SR-71 Blackbird

[avets8]

Hello everybody,

I'm building a 1/18 scale SR-71 Blackbird. I have another thread that I started in HPR thats got all my information on how I'm building it and the materials already up. I'll put the link down here so you don't have to go and find it.

https://www.rocketryforum.com/showthread.php?p=85253#post85253

Here are some pictures of what I've done so far. There are a few pictures in there of the drawings that I started with to get a general design. There is also one that shows a drawing of a panel that I took from a 1/72 model airplane that I built a few years ago. I'm using 1/4in birch plywood for the panels and blue insulation foam to fill in the gaps, then I'm fiberglassing the whole thing with 6oz fiberglass.

Thanks :cyclops:

 

[UPscaler]

What is the wing span? :cyclops:

This looks like a sweet project. What do you plan on flying it on?

 

[avets8]

It will have a 34in wingspan and it will be 63in tall.

As for what motor I'll go with, it all depends on what it weighs at the end. At first i predicted it to weigh between 6-7 pounds but I think now it will end up being more near 5-6. If it's on the higher side I'll probably use a 4G Pro38 I-470. If it's on the lower side might go with the 3G Pro38 I-350.

 

[avets8]

so its been a while since i last posted anything reguarding my build but as of right now its on somewhat on a standstill. i've finished cutting out the wood panels and i am continuing to cut out the foam pieces to go in between the wood. i have made a tube coupler/payload section to attach the nosecone and parachute and have made a baffle section. i will have pictures withing the next few days of all the stuff that i've done. i'm at school right now so i don't have any pictures with me at the moment.

reguarding the standstill, i can't start epoxying all the peices together until the tubular nylon that i ordered arrives. the problem is is that i ordered it a long long time ago and we contacted the shipping company and it was lost in transition between where we ordered it from and my home.

i'm going to try and keep doing as much as i can and hopefully the tubular nylon will show up and i can get the epoxying underway.

 

[UPscaler]

Do you have an REI store near you? I bought twenty feet of 9/16 inch TN for $4.40 there. Something to think about for future builds

 

[redsox15]

we (avets8 is my brother) ordered 300 yds for 60 but as he mentioned it got lost in the mail, a 12 lb box went poof/was too damaged to continue to be shipped (says the note that was attached to the box clipping we got). But the REI idea sounds like a great solution to the problem thanks!

edit: found an REI about 20min from our house!

Matt

 

[avets8]

alright, pictures as i promised.

the wood panel on the left is my baffle section that will be approximately 20" down the tube and will be epoxyed onto the bottom of the tube. the hook is for attaching my shock cord. i doubled up the panel and glued together 2, 1/4 in. birch plywood panels and then i fiberglassed the side that is going to be hit by the gases from the ejection charge.

the tube on the right is a coupler i made out of the body tube that will attach to the nosecone and slide out. again the hook is for the parachute and shock cord, which will be tubular nilon.

 

[avets8]

i hate technology.....:y:

i have more pictures but for some reason they wont upload to rf. i've tried changing the file formats and making sure they're not to big of files but they still wont work. i'll keep trying, hopefully i'll get a few more up.

thanks for being patient

 

[avets8]

heres a picture of the top half of the blackbird with the foam peices in it. the foam is only cut roughly for now but i will cut it more precisely once i have the other parts completed.

sorry for the delayed posts. i'm not very good at keeping the thread updated. :cyclops:

more to come, who knows when though...

 

[avets8]

the first picture:
these are the foam peices and wood panels from the previous picture just not on the body tube. i took them off so i can attach the baffle panel to the bottom of the body tube then slide all the foam peices back onto it later.

the second picture:
this is the nose cone/cockpit section of the rocket. its got some of the foam on but not all at the moment. the tubular nylon will be tied to the hook thingy (i forget the name of it) at the end of the tube. that tube is a coupler that i made out of the regular sized body tube so that it slides on and there are two dowels that fit into holes that keep the nosecose from rotating.

again, more to come...hopefully

 

[avets8]

this is my workspace, aka the floor. haha. :roll: just a random picture i took.

I just drilled holes in my lower panels to insert reinforcement dowels down the entire wing. i'll be working on cutting the 13th and 14th panels so that i can complete the lower half and start working on attaching the outer engine parts of the plane and then the outer wing sections which i decided to make in the non-panel method, instead its just a big peice of 1/4 in birch ply, like a fin would normally be.

thats all for now. more to come in about a week....maybe.

thanks.

 

[Rex R]

its either an eye-bolt or a screw-eye can't tell if it had a pointy end its a screw-eye .
looking pretty good at this point, expect it will look really nice when you're done.
rex

 

[avets8]

more pictures!

this is the nosecone. it is the cockpit to the tip of the plane. I havn't shaped it yet because I just cut out the foam templates today. I have to take the foam off again to glue the dowels in place before I can put the foam back on, clamp it, then shape and sand. I will be fiberglassing it later with 6oz glass.

i'm going to buy the tubular nylon from REI tomorrow so I can start glueing, clamping, and shaping the midsection of the blackbird (the part between the start of the wings and the cockpit).

all of my wood peices are cut out, but....there's a little set back: my scrole saw 'kinda' broke, so i can't cut out the center circles that the tubes have to slide through. any suggestions for other ways to cut out an inside circle?

what happened is that the screw that holds the blade attachment on the scrole saw got stripped as I was replacing the blade. The thing is, the screw made it into the screwhole sideways so now its jammed. :y: I can't screw it on any more, but i can't get it off either, and its not holding what it's supposed to hold on the arm tight enough, so the blade won't cut straight. I'm going to go to Home Depot or Sears or someplace to see if they can get the screw off because I've tried everything and it won't budge! right now all it can cut is the foam.

 

[avets8]

this is my other workspace, aka the garage. the machine on the right is the scrole saw that's 'kinda' broken.

I've only got 5 days of school left till I graduate (high school, wahoo! ) so i'll have more time to work on this. The Blackbird should start taking shape soon so keep watching and i'll post more pictures soon!

thanks

 

[davalf]

The build is looking great. I cannot wait to see the finished product.

Dave

 

[avets8]

ok, i need a little advice from some of you more advanced rocketry people.

the tubular nylon finally arrived!!! now for the length of my shock cord, i was thinking 30ft??? with 2.5 extra feet for tieing and loops and whatnot???

The overall length of the rocket is 63in and the shock cord mount is approx. 2ft inside the upper tube. Another fact is i'm predicting it to weight between 5-7 lbs when completed, depending on how the fiberglassing process goes.

any suggestions?

thanks

 

[davalf]

I know a lot of people use a lot of shock chord. I think you would be fine using half of that. I would say use 15-20'.

Dave

 

[avets8]

ok here are some more pictures:

i have completed the nose cose of the blackbird. i'm no artist so i did the best i could with the shaping and sanding of the the plane. i had a few screw ups on the way but it managed to turn out ok.

the nosecone is approximately 16 in long not including the tube at the bottom. the tube at the bottom is the the place where the parachute and shock cord will go.

 

[avets8]

i'm working on the lower section of the rocket now where the outer engines and outer wings of the plane are located. i've been cutting the rough outlines of foam for these sections and trying to figure out where the interior tubes need to be slotted for the flat panels that i am inserting will go. i'll have more pictures by next weekend.

thanks

 

[UPscaler]

anything new?

 

[sodmeister]

WOW ,I have never seen this before.I would love to see more of this build................PLEASE !!!


Paul

 

[avets8]

okay, I know I haven't really been doing to well on keeping my thread updated, but I haven't been able to work on this is a lonnng time (college....ahhh!) but I do have a more recent photo that I will post in a few minutes, just have to find it.

 

[avets8]

here is the most up to date picture of what i have done so far. the nosecone looks kinda funny because I tried fiberglassing it and it didn't turn out to well.

anyways its been going well, hopefully I'll be able to work on it soon.

the final rocket will be a little shorter than what it is in the picture right now because I haven't cut off the excess tubing yet.

 

[Scotty Dog]

When does a rocket become a plane, or become a "rocket" powered plane??? I would say "Hey,look at this guys plane" if I seen ya coming with it on your shoulder. Anywhoo- WICKED NICE !!!!!!!!!!! that would be something to see lift-off.

 

[UPscaler]

Very nicely done. That's beautiful.


Braden

 

[H_Rocket]

While nice, I would want a dead calm day to fly that thing. Considering the wing area and the skittishness I have seen in the smaller Estes kits, this one would give me pause.

 

[jsdemar]

While nice, I would want a dead calm day to fly that thing. Considering the wing area and the skittishness I have seen in the smaller Estes kits, this one would give me pause.

Best way around this is to trim it for a slight roll on boost. This works well on the Estes kit and also the larger RC SR-71 that I've seen flown by a guy in our club. Many years ago I did a plastic model conversion SR-71 with three motors and a lot of problems until I added tabs of the trailing edge for a little roll.

Can't wait to see this big one fly. Looks great, and it's a lot of work. Take some video!

PS: I've got an old Estes SR-71 for sale on Ebay (1985 version with wraps and decals), unopened. I also have a partially built one that I'll throw in for free for spare parts.

 

[avets8]

Best way around this is to trim it for a slight roll on boost. This works well on the Estes kit and also the larger RC SR-71 that I've seen flown by a guy in our club. Many years ago I did a plastic model conversion SR-71 with three motors and a lot of problems until I added tabs of the trailing edge for a little roll.

Can't wait to see this big one fly. Looks great, and it's a lot of work. Take some video!

PS: I've got an old Estes SR-71 for sale on Ebay (1985 version with wraps and decals), unopened. I also have a partially built one that I'll throw in for free for spare parts.

i designed it with fins on both the top and bottom sides for added stability. so it won't be an exact replica, but it needs to be able to fly

and i will only be using one central motor. thought about three but decided not to to minimize potential problems.

 

[aerospike]

5-6 lbs sounds way low to me given your construction methods. I'd say double that easy.

 

[berlinetta]

You going to bring this to Amesbury? It is going to look cool coming off of Pad C at the top of the hill.