Full size LOKI DART

I have a Balls project idea i have been kicking around for about a year now. I am thinking about building a full size LOKI DART. the only part of the whole build that eludes me is getting the weight for the 38mm dart correct.

Specs
76mm min diam booster on a LOKI M2550 Blue or a CTI 76mm Vmax
38mm min diam dart

any of you TRF'ers have experiance with boosted darts?

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That`s a very nice project to undertake , I really do like that !

I hope your site is up soon ,I need some stuff fomr you !

Paul T

like this...



I'm not sure if he's in this forum..PM me for contact info.

here's some dart stuff... https://www.lrrc-sgi.com/page/show/620444-pwn-dart-systems

here's another link.. https://tqc.yuku.com/topic/2967/Balls-rush

Tony

yep like that

Have you read the RRS 50 mile dart report? If not it is a really good read.
https://www.rasaero.com/dl_technical_reports.htm
Too bad RASAero can't take into account initial velocity. Otherwise I think it could be possible to simulate the entire rocket to burnout and then simulate the dart with an initial velocity/altitude.

COrocket said:

Have you read the RRS 50 mile dart report? If not it is a really good read.
https://www.rasaero.com/dl_technical_reports.htm
Too bad RASAero can't take into account initial velocity. Otherwise I think it could be possible to simulate the entire rocket to burnout and then simulate the dart with an initial velocity/altitude.

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You can hack it together by making a custom motor file with an impulse that instantly gives the rocket the proper speed at the proper altitude. It is easier for boosted darts than for two stage rockets, for which you must adjust the mass of the motor precisely to match the sustainer motor mass once the initial spike is finished.

I have wanted to build one forever but just do not have the proper field...

Talk to Karl Baumann at Aerotech; He collects LOKI darts and boosters; I think he worked on them at one point. He will have tons of information on the LOKI. He might have a booster he'd be willing to sell...but that's probably a long shot.

I saw a full size Super Loki Dart at a Battle Park launch back in the 90s. I think it flew on an I284. I'm pretty sure the fins were way bigger than scale.

Are they still launching them in Michigan?

Tony...thanks for the links. I love the pics of the spiral open breech launcher!op:

atxcple said:

the only part of the whole build that eludes me is getting the weight for the 38mm dart correct.


View attachment 113455

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I have dozens of Loki Dart files. Depending on which variant is flown, they range from 7-9lbs

Here's one for starters. 7lbs.

Keep in mind regular stability margins are out the window for this stuff as the CP does a MAJOR shift forward during high mach [3-5] flights. Once that dart leaves the booster , it will usually go immediately UNstable unless great care in design is taken. So getting the booster back under chute can be a problem. The real ones are designed to flat-spin in.

The Loki dart I have is 1.38" diameter and 10.16 lbs.
The weight it should be will depend on the motor used and total weight of booster.
https://www.dtic.mil/cgi-bin/GetTRDoc?Location=U2&doc=GetTRDoc.pdf&AD=AD0750796

Mark

here is the basic design file i have made still refining the fin shapes and weights

View attachment loki dart.rkt

okay here is a better / closer design file fin span is as close to 5" as i can get it and keep it stable

View attachment loki dart.rkt

Are you going to spin stabilize it?

i have been giving serious thought to trying it. even thought about building a working model of a LOKI Launcher.

More project report links for the sounding rocket that just appeared on the arocket mailing list:

https://www.rrs.org/wp-content/uploads/2014/01/Super-Loki-Dart-Meteorological-Rocket-System-1968.pdf

https://www.rrs.org/wp-content/uplo...er-Loki-Stable-Booster-Rocket-System-1973.pdf

Winston said:

More project report links for the sounding rocket that just appeared on the arocket mailing list:

https://www.rrs.org/wp-content/uploads/2014/01/Super-Loki-Dart-Meteorological-Rocket-System-1968.pdf

https://www.rrs.org/wp-content/uplo...er-Loki-Stable-Booster-Rocket-System-1973.pdf

Click to expand...

Winston, I have been trying to get on that list .but nothing . I have subscribe many times

You should read the 3 documents end to end before you finalize you design. They are really well done.

Darts do not have a motor. A true dart has a high section density and a boat tail aft end to maximize coast and minimize drag.

A true dart booster has a conical socket in the nose cone and a large diameter fast burn engine with very high acceleration and high burnout velocity. Drag separation occurs because the dart has a small diameter, high sectional density, low drag form factor while the burned out booster has a large diameter, low sectional density form factor which and slows down quickly due to aerodynamic drag.

The long heavy but skinny dart needs to be spin stabilized just like high sectional density bullets or it will go unstable due to the very small fins.

A Pro98 N10000 is the perfect dart booster.

Bob

For a minimum diameter dart.
What is the smallest altimeter available ?

MClark said:

For a minimum diameter dart.
What is the smallest altimeter available ?

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The G-Wiz LCX units are only 0.75" wide, but they are not readily available any longer. They are also accelerometer-based, which I suspect you want for this sort of project.

Here is a picture from the Thiokol rocket garden.

JohnCoker said:

The G-Wiz LCX units are only 0.75" wide, but they are not readily available any longer. They are also accelerometer-based, which I suspect you want for this sort of project.

Click to expand...

I think I have one, somewhere
M

MClark said:

I think I have one, somewhere
M

Click to expand...

If you don't, I do, let me know if you need it!