Johnnie

Just curious, has anyone ordered any of the Fisher Research hardware?

I just sent off for the 38mm intermediate system, and a special order 6-grain 54mm, so I should have something good to report in the coming weeks.

Johnnie

Johnnie

I have not had much of chance to play yet, but I did take some candid photos of the new hardware.

(1) 54mm 6-grain
(1) 6-grain 38mm
(1) 8-grain 38mm and
(1) 10 grain 38mm complete with all of the accessories.

Very nice custom laser etching on the 54mm motor.

Johnnie

ddmobley

Very cool, especially that 54mm!

Johnnie

Thanks Darrell, seeing this article prompted me to order. Of course I talked at length via email to Mike Fisher at Binder Design about specifics (communication was excellent) and in the end I have some great products. I Can't wait to fire one of these, hopefully by early to mid Fall, or Winter.

Johnnie

UncleVanya

What do you use for liners and casting tubes?

Johnnie

Propellant is cast into the casting tubes, hense the name, and the casts are inserted into the liners. The liners shield the inner casing walls from the flame front of the burning propellant.

Johnnie

Steve_Shannon

Johnnie,
I don't think he was asking the purpose of the casting tubes and liners. I think he wanted to know a source for them.

Johnnie

Hmmm, you are correct, I can fix that:

John Lyngdal - This email address is being protected from spam bots, you need Javascript enabled to view it

Most any size can be had here, and I have had excellent service for many orders.

Sorry for the mis-read, thanks for the catch Steve.

Johnnie

UncleVanya

Not always...

The 24mm EX discussion on this site showed that the 24mm casting tube from RCS was used as a liner and the BT20 body tube from ESTES was used as a casting tube.



And yes - you and Steve were correct. I was looking for the source - thanks for the info on John.

denverdoc

What I'm wondering is if anyone has seen the 16gr motor in action (actually recommends 4 by 4inch grs)? Seems like that could take a 38MD a long ways.

jsdemar

It would have to be essentially a "nozzle-less" design. Long bates-grain motors also end up with poor volume loading, after opening up the aft cores so much.

denverdoc

John, Could you elaborate a bit? In other words the aft grain core is so big that the throat provides no gain--I see more and more stepped core designs to avoid erosive burns, but wonder how the throat/core ratio plays into such designs when one is variable?

jsdemar

Take a look at the throat diameter you need to have a good starting Kn. Also take a look at the mass flux at the bottom grain. Burnsim can show you these values. One thing it doesn't show is the Mach number in the convergent section. If you have choked flow with Mach >1 at the throat, the gremlins appear out of nowhere.

Johnnie

Burnsim must be the shizzzle, is this program still available?

Johnnie

ddmobley

Absolizzle, my frizzle. Here is the URLizzle: http://www.burnsim.com/

JohnK3

Great! now we have Snoop DDMobley running the site! [grin>

ddmobley

Stranger things can happen! Don't tase me, Bro! Bro, don't tase me!

madmax

denverdoc,

I have seen that 16grain 38mm motor in action and let me tell you. It is awesome! Mike flew it at Brothers in August in a MD constructed out of aluminum and carbon fiber. The motor specs out to a K3551 if I remember and burns for less than a second. Don't blink or you will miss it! Little red flash and it's gone. Then you hear the sound of the burn. Just awesome to watch.

denverdoc

Sounds like a real neck snapper, and reminds me of a relatively tame MD 38 I flew on an H999--Wildman was giving em free to anyone who would take the challenge. Darn and I just invested in Loki 38 hardware. I use the 54 and 76 as well, brand loyalty.

ncrocketeer

How do they control erosive burning in a motor like that? I'm really curious, and want to learn about this as I know high L : D ratio motors are susceptible to this. I do know one can step grains, but I also read there was a point of diminishing returns where so much of the bottom grains have to be removed you loose solids loading. Can anyone comment on this? I am quite interested in motors like this, because the hardware weight can be kept down but still get very powerful motors. Obviously you guys already know this can increase performance.

denverdoc

I'm sure Darrell would have no problem with my "plugging" Texas High Power Ex forum on Yahoo Groups. Lot of seasoned vets there, and some good past threads on this very topic.

ddmobley

I only have a problem if you don't include a URL!

http://tech.groups.yahoo.c...etry-texas-experimental/

Johnnie

Thanks Darrell...

Johnnie

ncrocketeer

This place is awesome! It's like having one hand tied behind your back until you come here.

denverdoc

Well in some places, more like two hands behind your back while the little kid tries to beat the tar out of ya.

jsdemar

Hands tied behind your back and ducttape over your mouth.

Mike Fisher

You don't lose solids loading with stepped cores, you lose volumetric loading.

I use eight four inch long grains, .50" cores, none of the cores are stepped. The nozzle is .55" throat. Erosive burning can only be controlled to a certain degree. I use tepanol and about 2% extra curative so the grains come out slightly on the hard side. Solids are 85%. All grains get epoxied to the liner. The trick is to use a propellant formula with a really low exponent and design the motor to be progressive. Even then, it is scary fast.

I'm currently working on a 38mm L motor. I think it is workable if I use some of the oxamide that Mr. DeMar provided awhile back. The 38mm K uses no oxamide, but has other burn rate modifiers. I use a formula called Sunset Orange, or Sunset Red. Both have the same a and n.

The 38mm K3551 does 20K' in a minimum diameter rocket. I suspect it pulls close to 300g's and mach 3+. I've been using baro altimeters, but I do have a high g accelerometer unit to try out next season.

Hope this info helps.

Mike Fisher
Binder Design
http://binderdesign.com

landru

Mike, you have any test stand data for that there motor?

Mike Fisher

I had some for the 14 grain but lost it with the hard drive crash. The 14 grain was 1100lbs thrust for .6 sec. The 16 grain has a .5 second burn so probably ~1200lb. thrust. Put that in a 2 lb. CF rocket and hope it holds together. Pressure is running between 1,200 and 1,800 psi. I catoed a few motors when I tried some 400 micron AP. The larger particle sizes impart a high exponent, coupled with a higher erosivity.

denverdoc

Mike,

Near noob status here--just a brief explanation as to why the exponent goes up with 400mu AP would be helpful. I know the burnrate typically increases with smaller sized particles (I also have read that the right ratio of small/medium/large particles can lead to optimal packing in some cases).

BTW keeping together that 2 # rocket sounds like a helluva challenge.

Mike Fisher

That was a surprise to me too. This information was provided to me by John Lyngdal, who got it from Gary Rosenfield. Empirical testing proved it. I flew this same motor for about a dozen firings, then decided to try some 400 micron AP instead of my usual 200 micron thinking I could slow down the burn with it. After a couple of the loudest 38mm catos that you've ever heard, I was provided with this information. I switched back to 200 micron and all was well. If I use 400 micron, I mill it and end up with a nice random particle distribution that actually has a smoother burn and better mechanical properties. At pressures at or above 1,200psi, 400 micron AP will do bad things to your exponent.

Mike

landru

Mike,
If you don't mind sharing, what formula are you using? I'm in the process of making bigger badder motors for my balls style 38mm, and am curious if you are going the superfine AP/metals/catalyst route or had some standard 200um formula tweaked. I would LOVE to put that motor in this rocket
Current version weighs .8lbs without motor.

~Andrew Diehl, MDRA

Mike Fisher

Are Ed Rowe and Mike McBurnett from MDRA? They've been flying it for awhile, you might have seen it in action. It is called "Orange Sunset".

Pictured is the "Red Sunset" variant. Photo by Rick Clapp.

Mike

landru

*click*
Ohhhhh! That orange sunset.
It all makes sense now. I saw Mike fly an OS load at the last launch. Can't believe I didn't associate Orange Sunset w/ Sunset Orange. Must be late.

Very nice rocket btw, sick minds think alike

~Andrew

Mike Fisher

I was the one who got the names backwards in the earlier post sorry. You're right, must be late.

Mike

ncrocketeer

Thanks Mike for that info. That's awesome stuff. Those numbers are just sick! I appreciate the info on the solids loading and volumetric loading. I'm learning and am in the noob phase also. That is some incredible power, and it's why I'm getting into EX.

That info on the particle size is very interesting. I also liked the picture. That rocket was really nice. That's some really neat stuff. I'll have to get up that way one day, and see some of that. It looks like you guys are launching some serious stuff. I'm kinda partial to red motors, but that is extreme red. A K3551 in a 38mm. That's just oustanding. I've got alot of motors to fly before I work my way up to those kinds of speeds and altitudes anyway, but I love learning this stuff.

Thanks for the help, and the info. it is greatly appreciated.

Johnnie

Ok, I have the formula for the Orange Sunset, but I'm a huge fan of a Reds propellant, is this variant availlable anywhere?

Johnnie

Johnnie

Um, looks like I could just replace some of the calcium carbonate with Strontium carbonate...duh!

Never mind...bit of a brain fart

Johnnie

heada

*sitting here, waiting for the mods to wipe this thread clean because of talk about formulas*

Oh...thats right! This is RP and things like this can be discussed!

-Aaron *who has no EX experience but would like to get some someday*

WillCarney

I have tested and flown 24mm G and H motors using the RCS/BT-20 tubes.
No burn through with Brilliant Blue propellant. I would not suggest long burn
motors with these tubes. I used them because of the size. I have not found
phenolic tubes of the right size for 24mm liners. Got a source for small one's?

William

Mike Fisher

Yup. Just sub out all of it for the strontium.

A few people have given me a bad time for flying a "dumbed down" formula, but if it allows you to get more propellant in the tube, I say go for it. I had to remind these same people that they are doing the same thing when they choose to make their formulas pourable. I like my solids around 85%, but I have to vacuum mix.

Mike

denverdoc

Mike,

Is that mixing under vacuum or post process vacuum. Since my mixer works bottom up, I can go either way.