M.I.R.V. Gryphon - Anyone build one?

[scottluther1369]

I want to screatch build the Seattle Rocket works MIRV Gryphon. I found the plans but they don't list body tubes (I'm assuming BT-5 since they use A engines), but I have no idea how long each of the tube sections are. Anyone have an experience with this kit?
Thanks!
--Scott

 

[hokkyokusei]

I built one. Easy enough to clone, but I believe the mini-booster motors are OOP.

 

[Starbug]

Plans available - https://plans.rocketshoppe.com
Let me know if you still need measurements. I have the "remains" of my Gryphon somewhere. I'm sure I can take some measurements of what's left at least! Its only flight, in fact, was a drag race with Hokkyokusei at the IRW in Scotland. IIRC, he won, with most bits intact on landing and most motors lit!

It's a nice model. Good luck with the clone.

Pete

 

[scottluther1369]

Do you have the length of body tubes used( first stage and uper stage)???? As well as the nose cones used?
Thank you!
--Scott

 

[hokkyokusei]

The tubes for the booster are 110mm long. The Sustainers are made from two tubes, both 110mm long. The nose cones are 65mm long. Fin dimensions:

 

[scottluther1369]

Thanks!!!!
Any pointers! I always mess up glueing in the BT-5 engine rings. I end up glueing in the engine spacer no matter how fast I putt out the engine. Any good general pointers about building it and flying it would be greatful! It's my next project. Oh how thin are the fins?
Thanks for all the help!
--Scott

 

[hokkyokusei]

Mark a long, thin piece of scrap balsa to be the length of the motor. Put a dab of glue on the end and feed it up the middle of the body tube until the mark is level with the end of the tube. Then wipe the glue around the inside of the tube. Might take a few goes. Push the thrust ring in with a spent motor and pull out immediately when you get to the required position. Shouldn't stick, because the only place there should be glue is way up at the top where the thrust ring is.

Hope that helps!

Sustainer fins are 1mm basswood, the booster fins a shade over 2mm and balsa.

 

[Daedalus]

This would make a good model to upscale as B6-0 and C6-0 motors are still available and with B to A staging would give a much better chance of recovery.

 

[hokkyokusei]

If you were to attempt an upscale, there's a good chance it could turn out something like this:

Actually, I didn't do four motors, I reduced it down to three. 18mm motors come in packs of three you see...

 

[adrian]

When flying the MIRV Gryphon, check that the liners in the booster tubes aren't obscuring the vent holes. Also check that the sustainers will separate easily, because if they don't, you're going to have to replace the charred remains of what was your booster.

The A10-0T is indeed out of production, so unless you have your own stock of them, an 18mm upscale is a good idea! The sustainers can still be powered by 13mm motors if you wish; a B6-0 or C6-0 will ignite an A3-4T.

Here's my own rocket based on the MIRV idea, only I decided to go insane. MIRV Gatling

 

[Micromeister]

speaking with Estes a few months ago, I ask about the A10-0t situation. At that time Estes maintains there are thousands of CASES of A10-0T motors out in the warehouse systems. Check with our suppliers, Request them be number. Shoot buy a Case (12 packs) I was also told again..about the 3rd or 4th time i've pitched a tissy over the stop in 13mm booster motors. That went the demand again returns for these smaller boosters that will indeed be put back in the manufactureing cue. I stand hopeful folks will get out there, find this glut of A10-0t's and use them up! I have my 4 cases... I can't do it by myself... Lets burn some A10-0t motors

 

[BobH48]

Originally posted by Micromeister
..... there are thousands of CASES of A10-0T motors out in the warehouse systems...... I stand hopeful folks will get out there, find this glut of A10-0t's and use them up! ... Lets burn some A10-0t motors

Fliskits Triple Threat saucers and Art Applewhites saucers are perfect for these engines.

I can go out in the back yard and burn a couple packs in no time in the saucers and not worry about losing them.

A perfect back yard combo.

Nobody is going to make 13mm staged kits until the boosters are certified again so lets burn up the old ones.

EDIT: I had a hard time finding these booster engines at first. I got mine from Discount Rocketry but they weren't listed on their engine page but I found a link by doing a Google search on "A10-0T"

 

[Daedalus]

Originally posted by adrian
Here's my own rocket based on the MIRV idea, only I decided to go insane. MIRV Gatling

Yes, that is a very, very silly model - precisely how much of it did you get back

Really, I like it - just it will be a PITA to get it back.

 

[adrian]

The booster. Which didn't surprise me. For one thing, there was a wind blowing, so the sustainers drifted to random distant locations. For another, I'd flown this single booster and sustainer, and the sustainer from that one didn't return either, also due to prevailing wind.

In theory, the sustainers were re-usable. In practice, they weren't likely to return, so I made them as cheap and simple as possible.

Mind you, I didn't expect to get all the sustainers from the original MIRV Gryphon back, either. I didn't know SRW supplied free spare parts, so I bought a flock of Gryphons.

 

[Daedalus]

Originally posted by adrian
In theory, the sustainers were re-usable. In practice, they weren't likely to return, so I made them as cheap and simple as possible.

How cheaply? looks like a rolled paper nose cone. Was the tubing rolled too or was that real body tube?

Mind you, I didn't expect to get all the sustainers from the original MIRV Gryphon back, either. I didn't know SRW supplied free spare parts, so I bought a flock of Gryphons.

Free spare parts, now I know why SRW left the rocket business. Pity they produced some really nice kits. I think all of them were discontinued but available from R&T when I got into rocketry. I didn't get any as they (especially the MIRV) were 'too expensive' - now I fly clusters and HP and think the MIRV was reasonable, a total change of perspective. I must get some BT20 on order and upscale the MIRV

 

[scottluther1369]

How far down from the top of the first stage body tube is the top of the holes (vents). There is a little template I got with the plans but it makes it way too close to the top when looking at the tubes. Can you please give me the measurement? Also can you recommend the best plans out there so I'm working from the best set and printing resolution needed. These seem normal 72 dpi instructions but the BT-5 alignment guide and fin templates look plausable. Should I print at 300 dpi??? I'm not sure.
Thank you so much! I can't wait to start this one!!!!
You guys are really great!
--Scott

 

[scottluther1369]

Could you please include the measurements of the fins? gpoehlein was kind enough to include them for my screamer and it made all the difference. These are BT-5's right. What nose cones sould be used? Being new I have nothing but questions but your help I am learning A LOT, I'm having a great time and hope to contribute soon!
Thanks again!
Scott

 

[hokkyokusei]

Originally posted by scottluther1369
Could you please include the measurements of the fins?

For the Gryphon? I posted the dimension of the fins already.

 

[Fishhead]

Originally posted by scottluther1369
Could you please include the measurements of the fins? gpoehlein was kind enough to include them for my screamer and it made all the difference. These are BT-5's right. What nose cones sould be used? Being new I have nothing but questions but your help I am learning A LOT, I'm having a great time and hope to contribute soon!
Thanks again!
Scott

https://plans.rocketshoppe.com/srw/srwMG/srwMG.htm

 

[adrian]

Originally posted by Daedalus
How cheaply? looks like a rolled paper nose cone. Was the tubing rolled too or was that real body tube?

It was real BT-5 (or rather, Totally Tubular's equivalent). The nose cones were indeed rolled paper.

Free spare parts, now I know why SRW left the rocket business. Pity they produced some really nice kits.

When I first heard of them, their entire catalogue was a single sheet of paper with the Nike Smoke on one side and the MIRV Gryphon on the other. As they didn't handle credit cards, I had to use an international money order to pay from the UK. Which was another reason for buying a batch of Gryphons. Apart from the value of the currency being ordered, there's a charge for an international money order which is the same regardless of value. I added up the total cost of the order, divided by the number of rockets, then sold a couple on to other people at cost price. They therefore didn't have to pay the full charge for a money order and neither did I. (I wasn't undercutting any UK dealers. At that time, I was the only person in the UK in possession of Gryphons. )

I must get some BT20 on order and upscale the MIRV

Or join Micromeister's campaign to get the A10-0T back in production...

 

[scottluther1369]

I did download the plans. Printed them at 300 dpi but the vent holes look too close to the top of the (like 1/8 of an inch_tub in relation of the templat and when I looked at the picture of the vent holes they just don't look right. So I was hoping that any one who had one could give me the vent hole measurements and the fin measurements. Should I just go with the plans as printed???? I'm a little worried with a rocket like this it won't come out right with the right sizes. I do have the body tube lengths though! Thanks.
Thank!
--Scott the newbie <- my new nickname.

 

[hokkyokusei]

Originally posted by scottluther1369
I did download the plans. Printed them at 300 dpi but the vent holes look too close to the top of the (like 1/8 of an inch_tub in relation of the templat and when I looked at the picture of the vent holes they just don't look right. So I was hoping that any one who had one could give me the vent hole measurements and the fin measurements. Should I just go with the plans as printed???? I'm a little worried with a rocket like this it won't come out right with the right sizes. I do have the body tube lengths though! Thanks.

The tubes came with the vent holes pre-cut. The template is for the booster protector inserts. If you look at the image of the booster tube itself, you will see that the vent is much further than 1/8 inch from the end of the tube. I'll measure the diameter and position of the vent holes when I get home tonight.

As for the fin dimensions, I already posted reply with a diagram attached showing all the dimensions. It's in the same post that I gave the tube and nose cone lengths. Couldn't you open it?


Hey! Post 1000

 

[scottluther1369]

Thank you!
Yes, I couldn't open the last file you sent me. I greatly appreciate all the effort you are going to for me! And as I recall the fin size is super thin...correct (on the upper stages)
Thanks again! I owe you one - well many : )
--Scott <the newbie)

 

[hokkyokusei]

OK, I've put the image inline this time:

As previously stated: "Sustainer fins are 1mm basswood, the booster fins a shade over 2mm and balsa."

The vent holes are 7mm in diameter positioned 12mm below the top of the booster. There are two vent holes per tube, 180 degrees apart.

 

[scottluther1369]

Okay, if the upper stage sustainers are made from two 110mm body tubes, why can't I just use one tube 220mm long or is there some reason the 110's must be joined together? I can still attach the streamers at the top of the body tubes can't I? Educate me here please (on this subject that is) : )
Thanks!
--Scott <the newbie>

 

[hokkyokusei]

I don't see why you couldn't do that.

 

[adrian]

Supplying the sustainer as two 110mm tubes probably made production easier (just keep cutting 110mm tubes for both sustainer and booster), and also meant the box could be smaller. The sustainer tubes are supposed to be glued together, it's not supposed to break in the middle.

So, yes, you could use a single 220mm tube instead.

Now I think about it, I believe the coupler between the two body tubes served another purpose - that's where the kevlar shock cord was secured. There isn't much room in a BT-5, so if you have the shock cord mount near the top of a single body tube, you may have trouble getting the streamer in, and the ejection charge may have trouble getting it back out...

 

[scottluther1369]

Should I go with the way they do it? I already cut the 220's and bought some kevlar thread. I figured it wouldn't make too much diffenence If the thread was going to hang down there anyway. but they do wrap the thread around the joiner. I can easily cut them in half. Or couldn't I just use a joiner to attach the kevlar thread around a joiner and slide it down from the top anyways. Just don't want to do anything to make this unusual rocket unstable.
Thanks!
--Scott <the newbie>

 

[scottluther1369]

Hey! If I go my way I can change my nickname from just
Scott <the newbie>
to:
Scott <the newgbie and CATO Master>

 

[scottluther1369]

Well, here is a picture of my scratch build copy of Seattle Rocket Works M.I.R.V. Gryphon. It took some doing from this newbie but I got it done with a lot of help from you guys. Thanks. Heres the picture of it:

https://homepage.mac.com/scottluther/PhotoAlbum18.html

I don't have the nose cones on very tight so the paint doesn't look as good as it will when it's ready to fly. It kind of a delicate rocket.
Now I just have to work out the fins on the upscale screamer and thats next. Not sure how to do slotted fins and what to ask for in slotted body tubes. I'm not sure what the fin will look like with these slots (how long etc)yet.
Thanks guys!
--Scott