first time scratch guidance?

[skybuster]

hey everyone,

I started a thread a week back on the Astron Farside X, and I've been thinking of making my own, but different than the original, I'm a bit of an altitude junkie and I'm thinking of up-scaling it to take Estes' new E12's and E9's. Thankfully, I believe this is within the NAR rules, so my idea is proceeding. Now, I've never done a scratch build, but, summer is coming up and I've gotta build this since I'll have from the end of May till the beginning of September to do so, and as usual, I have questions.

First one: since jumping up from standard engines to E's which are an inch longer and also larger in diameter, the original BT50 will be too small, I was wondering if BT52 would work while having the engine mount inside?

Second: I'm going out on a limb and assuming that since the root length of the fins will extend an inch, there is a ratio between the new and old fin size should that apply to all sides?

Third: With ratios, the original body to payload had a ratio too, could this just be found by comparing the booster stages to the body length and then to the payload?

Fourth: back when I built the interceptor E, there was an orange adapter so that it could run off of C11's and D's. Any ideas of how to make all three stages take one but keep it inside the engine mount?


thanks for any help, there may be a few more I've forgotten and may post later.

[CPUTommy]

Ok.. from someone who loves watching an E-9 get max altitude as possible I can only give you my experiences..

First. Get an estes body tube. I believe its a BT 20 tube..( I could be wrong on the body tube size)

Then, Get some balsa or bass wood, cut out your fins, Put a nice leading edge on all the surfaces except the one that mounts on the body tube, Paper the fins, and prime, then paint the rocket. Do the traditional estes shock cord mount, Then install the engine stop or "motor mount stop" in the rocket after you test fitted the engine. ( I use a straw to get the glue down and around the ring )

I can supply pics and more detailed instructions if you want. I can say this.... Launching an E-9 in a scratch built rocket makes everyone watching say.. OH WOWWWWWWW... They fly !!!

Now for the bad part.. All of my rockets that are designed for E-9's are essentially what we call "God Rockets" Cuz its a one way trip to god..

Get pics BEFORE you launch because your chances of getting them back are slim...

here is the proof.. LOL

http://www.youtube.com/watch?v=S7pLq...3&feature=plcp ( 1:22 seconds is a god rocket..)

Good luck and one more peice of advice.. Build MANY MANY rockets.. They are a BLAST !!!!

Tom

[[POW]Eagle159]

Ok.. from someone who loves watching an E-9 get max altitude as possible I can only give you my experiences..

First. Get an estes body tube. I believe its a BT 20 tube..( I could be wrong on the body tube size)

Then, Get some balsa or bass wood, cut out your fins, Put a nice leading edge on all the surfaces except the one that mounts on the body tube, Paper the fins, and prime, then paint the rocket. Do the traditional estes shock cord mount, Then install the engine stop or "motor mount stop" in the rocket after you test fitted the engine. ( I use a straw to get the glue down and around the ring )

I can supply pics and more detailed instructions if you want. I can say this.... Launching an E-9 in a scratch built rocket makes everyone watching say.. OH WOWWWWWWW... They fly !!!

Now for the bad part.. All of my rockets that are designed for E-9's are essentially what we call "God Rockets" Cuz its a one way trip to god..

Get pics BEFORE you launch because your chances of getting them back are slim...

here is the proof.. LOL

http://www.youtube.com/watch?v=S7pLq...3&feature=plcp ( 1:22 seconds is a god rocket..)

Good luck and one more peice of advice.. Build MANY MANY rockets.. They are a BLAST !!!!

Tom

It would be Bt-50 tube.... The Bt-20s are the 18mm motors

Nice video!

[Rocketbuilder]

I used an E to D adapter in a multi-staged rocket, and the adapter worked fine.
Here is a link to a page where you can download the RS file of the Farside X. If you know how big of an upscale you are doing (i.e. 2.3X, etc.) you can scale the rocket in OR. Then you can modify it however you want from there, just be sure to check it in all configurations.
Hope this helps.

[CPUTommy]

here is another vid of my scratch builts..

I will tell you this though.. There is nothing like putting an aerotech E30 in the same rocket... (you will need a spacer to make up the diffrence from an E-9 estes to an E30 aerotech.. Just cut down a used up E-9 motor for the spacer)

If you chose to go that route.. (E30) I strongly suggest you use epoxy instead of C.A. !!!! I lost a fin due to the bond... Epoxy seems to be much more durable under the stress's...

http://www.youtube.com/watch?v=zuN7o...2&feature=plcp

Timestamp.. 2:40 is one of 3 that were built and all lost..
Timestamp.. 3:50
Timestamp.. 4:30

out of the three I was able to recover 2 of them... A Definate BONUS.. they live to be lost another day....

The other rockets are all Launch pad rockets.. Havent personally seen one of them fly straight..

Tom

[skybuster]

Ok.. from someone who loves watching an E-9 get max altitude as possible I can only give you my experiences..

First. Get an estes body tube. I believe its a BT 20 tube..( I could be wrong on the body tube size)

Then, Get some balsa or bass wood, cut out your fins, Put a nice leading edge on all the surfaces except the one that mounts on the body tube, Paper the fins, and prime, then paint the rocket. Do the traditional estes shock cord mount, Then install the engine stop or "motor mount stop" in the rocket after you test fitted the engine. ( I use a straw to get the glue down and around the ring )

I can supply pics and more detailed instructions if you want. I can say this.... Launching an E-9 in a scratch built rocket makes everyone watching say.. OH WOWWWWWWW... They fly !!!

Now for the bad part.. All of my rockets that are designed for E-9's are essentially what we call "God Rockets" Cuz its a one way trip to god..

Get pics BEFORE you launch because your chances of getting them back are slim...

here is the proof.. LOL

http://www.youtube.com/watch?v=S7pLq...3&feature=plcp ( 1:22 seconds is a god rocket..)

Good luck and one more peice of advice.. Build MANY MANY rockets.. They are a BLAST !!!!

Tom

Wow nice video! Thanks for the info, I can't wait to begin this project!

[blackbrandt]

I believe the E motors are 29 mm

[skybuster]

Blowing off some homework tonight (have first off in the morning, can do it then) in order to begin planning out this build. So far, I have started with the lower stages, since they're each going to be extended by an inch on the root edge, I figured out that the ratio was 1.445 for one root side of one fin, and have so far printed out the fin cut outs at 145% original size. (Stop me if I'm doing anything wrong). I have also found a ratio to the main body tube to the payload section of 1.5 to bulk it up a bit. Now, I’m a little stuck. I’m trying to keep everything as close to the original size (diameter wise) but the E engine will force me to have to go up a bit, so I’m looking at some of semroc’s BT52 since it’s marginally larger, and was thinking of using a standard mount which would fit inside. Now, there’s not that much room between the mount the theoretical BT52 tubing, and to get the mount mounted, that would require some rings sanded down pretty far, or a tube coupler. Any thoughts or suggestions if this would work with such tight tolerances, or do the tolerances really matter in the long run?


Thanks for the help!


Oh, and are there any math equations to predict altitude?

[bjphoenix]

If you are building what is essentially a minimum diameter rocket to use an Estes E motor you will get plenty of altitude. For comparison the Cherokee-D is BT-55 and it will get a lot of altitude on a D motor, certainly as much or more than I want.

[JStarStar]

hey everyone,

I started a thread a week back on the Astron Farside X, and I've been thinking of making my own, but different than the original, I'm a bit of an altitude junkie and I'm thinking of up-scaling it to take Estes' new E12's and E9's. Thankfully, I believe this is within the NAR rules, so my idea is proceeding. Now, I've never done a scratch build, but, summer is coming up and I've gotta build this since I'll have from the end of May till the beginning of September to do so, and as usual, I have questions.

First one: since jumping up from standard engines to E's which are an inch longer and also larger in diameter, the original BT50 will be too small, I was wondering if BT52 would work while having the engine mount inside?

Second: I'm going out on a limb and assuming that since the root length of the fins will extend an inch, there is a ratio between the new and old fin size should that apply to all sides?

Third: With ratios, the original body to payload had a ratio too, could this just be found by comparing the booster stages to the body length and then to the payload?

Fourth: back when I built the interceptor E, there was an orange adapter so that it could run off of C11's and D's. Any ideas of how to make all three stages take one but keep it inside the engine mount?


thanks for any help, there may be a few more I've forgotten and may post later.

Well, you could make a 3-stage E-motor version of the Farside-X using BT-50 for your airframe, but this would make it a minimum-diameter rocket. Of course since E9's are longer than conventional 18x70 motors, you would have to lengthen Stages 1 and 2 accordingly.

If you wanted a more-than-minimum diameter design, you could use Semroc BT-52 or just upscale to Estes BT-55, and use 5055 engine mounts in each stage. That way you could use TTW fins if you wanted to.

If you are building the Farside-X version with the big payload section up front I don't think the fins would need to be upsized. That's a lot of weight up front.

Now, on the original Farside design IIRC (I built one 40 years ago) the motors are all held in the stages by friction fitting and staged by the cellophane-tape method.

This could turn into a problem during your second-stage burn -- by the time you approach burnout of stage 2, after 6-some seconds of powered flight -- that thing is going to have some serious speed built up, and friction-fitting is going to be pretty risky. Unless your friction-fitting is strong as a vise (see the 'Motor Stuck' thread on the LPR forum) it is possible drag could peel the stage right off.

Although, if you are building the Farside-X, with the big payload section up front, my off-the-top-of-the-head guess would be it would still be stable flying in CHAD mode if stage 2 did peel off.

However, you could also use gap staging, lengthen each stage by an inch or so, and hold all 3 motors in their respective stages using motor hooks.

Bottom line, unless you are gonna fill the payload section with sand, or flying from Black Rock or something, you could be talking about a "God Rocket" anyway. A 3-stage E9-0/E9-0/E9-8 is gonna put that thing way, way, way up there.

[CPUTommy]

Dont over complicate it.. Keep it simple.. Its not hard ..

Pics

1- Body tube Bt 50, Nose cone, Balsa stock, and Red Motor stop Notice the E motor and the D motor I use for reference for the motor stop.
2- Motor stop installed, I put the motor stop in the rocket to the desired location then put CA in a straw and use the straw to drip the bead around the motor stop WITH OUT MOVING IT. you dont want any glue in the tube before the motor stop or your motor will have problems fitting.. USE the straw to put the CA where it belongs, Tip the rocket to the straw horizonatily , then tilt both vertically and the CA will flow around the stop.
3- Motor installed (notice that due to shrinkage and or humidity you may have to take the outter layer of paper off of the motor)
4- How the rocket is in static display so you can get the picture.

Build em !!!! Fly em !! and LOSE THEM !!!

P.S. Streamer recovery is a MUST unless you have a very open field and a spectatular set of eyes..I also use Reflective skirt material in my streamers to aid in tracking.. and if the motor kicks out at ejection, youll be amazed at how long it takes for the rocket to return to earth.. One of mine took close to 14 minutes at free falling with streamers and no motor.. Incredible..

Good luck..

Tom

[JStarStar]

Well, Skybuster back in the OP said he has from May to September to build it, so I would guess that means:

1) He wants to put a little planning/effort/technique into it, and

2) In light of 1), probably wants at least a decent fighting chance to get it back.


If you just want to slap together a 3-stage minimum-diameter 3FNC BT-50 to fly on E9/E9/E9, that probably shouldn't take more than a couple nights to put together.

Just cut the tubes the right length, glue in the engine block in stage 3, glue on the fins, rig yourself up a nice long streamer, tape up the motors and go.

So yeah, you can make it as over-complicated or under-complicated as you want.

[skybuster]

Well, you could make a 3-stage E-motor version of the Farside-X using BT-50 for your airframe, but this would make it a minimum-diameter rocket. Of course since E9's are longer than conventional 18x70 motors, you would have to lengthen Stages 1 and 2 accordingly.

If you wanted a more-than-minimum diameter design, you could use Semroc BT-52 or just upscale to Estes BT-55, and use 5055 engine mounts in each stage. That way you could use TTW fins if you wanted to.

If you are building the Farside-X version with the big payload section up front I don't think the fins would need to be upsized. That's a lot of weight up front.

Now, on the original Farside design IIRC (I built one 40 years ago) the motors are all held in the stages by friction fitting and staged by the cellophane-tape method.

This could turn into a problem during your second-stage burn -- by the time you approach burnout of stage 2, after 6-some seconds of powered flight -- that thing is going to have some serious speed built up, and friction-fitting is going to be pretty risky. Unless your friction-fitting is strong as a vise (see the 'Motor Stuck' thread on the LPR forum) it is possible drag could peel the stage right off.

Although, if you are building the Farside-X, with the big payload section up front, my off-the-top-of-the-head guess would be it would still be stable flying in CHAD mode if stage 2 did peel off.

However, you could also use gap staging, lengthen each stage by an inch or so, and hold all 3 motors in their respective stages using motor hooks.

Bottom line, unless you are gonna fill the payload section with sand, or flying from Black Rock or something, you could be talking about a "God Rocket" anyway. A 3-stage E9-0/E9-0/E9-8 is gonna put that thing way, way, way up there.

wow! thanks for the info! Have been thinking of using the BT55 but I noticed that Semroc doesn't have a balsa reducer that's about the same length or longer than the original Farside had for the payload model. Just a few questions about terminology: TTW fins, and CHAD mode, could those be explained? thanks.

I never knew that gap staging was possible! Any experience with it? sounds like that would be a great solution to this build.

Oh, and are there equations out there to find the velocity and altitude?

Thanks again

[skybuster]

Dont over complicate it.. Keep it simple.. Its not hard ..

Pics

1- Body tube Bt 50, Nose cone, Balsa stock, and Red Motor stop Notice the E motor and the D motor I use for reference for the motor stop.
2- Motor stop installed, I put the motor stop in the rocket to the desired location then put CA in a straw and use the straw to drip the bead around the motor stop WITH OUT MOVING IT. you dont want any glue in the tube before the motor stop or your motor will have problems fitting.. USE the straw to put the CA where it belongs, Tip the rocket to the straw horizonatily , then tilt both vertically and the CA will flow around the stop.
3- Motor installed (notice that due to shrinkage and or humidity you may have to take the outter layer of paper off of the motor)
4- How the rocket is in static display so you can get the picture.

Build em !!!! Fly em !! and LOSE THEM !!!

P.S. Streamer recovery is a MUST unless you have a very open field and a spectatular set of eyes..I also use Reflective skirt material in my streamers to aid in tracking.. and if the motor kicks out at ejection, youll be amazed at how long it takes for the rocket to return to earth.. One of mine took close to 14 minutes at free falling with streamers and no motor.. Incredible..

Good luck..

Tom

Thanks for the tip on the streamer!!! My dad's has the parachute in it, and I'd hate to see how far it'd drift on a slightly windy day at 2500 feet!

14 minutes I can't pay attention that long in my AP English lit class...then again, it's my lit class. Is the reflective material you use similar to what Apogee sells?

thanks

[skybuster]

Well, Skybuster back in the OP said he has from May to September to build it, so I would guess that means:

1) He wants to put a little planning/effort/technique into it, and

2) In light of 1), probably wants at least a decent fighting chance to get it back.


If you just want to slap together a 3-stage minimum-diameter 3FNC BT-50 to fly on E9/E9/E9, that probably shouldn't take more than a couple nights to put together.

Just cut the tubes the right length, glue in the engine block in stage 3, glue on the fins, rig yourself up a nice long streamer, tape up the motors and go.

So yeah, you can make it as over-complicated or under-complicated as you want.

All true! I'm trying to build this to a good sized replica, just taking the big LPR engines, and since I'll have a lot of time this summer, I'm more than willing to take the time to do so.

[skybuster]

was searching around the archives and found [POW]Eagle159's dual parachute deployment for the lower stage on his rockets. http://www.rocketryforum.com/showthread.php?p=287999

Just wondering how well that's worked out so far?

It's pretty ingenious and I'd like to use something like that so I can find the lower stages, maybe have the parachutes for stage one, and streamers for the second stage.

[[POW]Eagle159]

was searching around the archives and found [POW]Eagle159's dual parachute deployment for the lower stage on his rockets. http://www.rocketryforum.com/showthread.php?p=287999

Just wondering how well that's worked out so far?

It's pretty ingenious and I'd like to use something like that so I can find the lower stages, maybe have the parachutes for stage one, and streamers for the second stage.

Yeah,I haven't flown it again yet.... But it worked very well.

One thing to remember is to keep the chutes packed tight so they just slide/fall right out.

-Another thing to try is to not have a nose cone in the tubes that holds the chutes, so when it stages, the tubes that held the chutes now act as tube fins.......Ahhh now Im thinking...