BPASA

   Home     Movies     Apollo Saturn V     Hot Rod Nitro FireBall     TOGinator     VooDoo Daddy     NERRF     Rocketflite MF tests

Rocketflite MF Ematch Tests 2008 

Extensive ground and flight testing of prototype Rocketflite MF (Magfire) ematches

Bottom line for all flight tests in 2008:
99% reliability firing AP and BP engines and ejection charges
 

The year before, in 2007, I used Rocketflite (ML) Magnelite igniters to light all cluster flights, and had 99% reliability igniting engines.

Flew a total of 16 cluster flights in 2007, igniting between 3 and 8 engines at the pad. The most  complex flight the VooDoo Daddy's successful flight on 16 D engines in 3 stages. (picture 1)

Magnelite igniters come in a kit, the pyrogen and wires are purchased and dipped by the user. Dipping is a simple one step process and the igniters are dry and ready to use in an hour.
(please see making Rocketflite ML (Magnelite) igniters farther down on the right)

The wires already have the nichrome bridge wire soldered in place, and their long leads eliminate whip clips. ML wires are available in 4 sizes capable of firing AP engines from 29mm up to M and larger, and BP engines A and larger.

Method I used and refined in 2007 for reliably clustering up to 8 engines:
>  Use Rocketflite ML (Magnelite) igniters – check wire resistance when making igniters
>  Secure parallel wiring, all igniter leads twisted directly together and then twisted around pad
    power clips (no whip clips, eliminating many electrical failure points)
> Strong 12V ignition system – with a relay at the pad
> Sand propellant slots – remove oxidation

Plan for the 2008 flying season > More Clusters and Dual Deployments

First Flight Tests

In order to fire many engines in clusters it was necessary to minimize ignition current load while maintaining reliability. Rocketflite had just released their (MF) Magfire ematches intended for firing BP ejection charges.

On 1/12/08 used the new MF ematches, wired 3 in series, to successfully launch the Applewhite 10” saucer three times on 3x D11-P engines.
(pictures 2 and 3)

Used series wiring for the MF’s to greatly reduce the current load on a 12V launch system. Ignoring transient effects for simplicity, comparing approximate current loads:

ML igniters, 3x in parallel: 1ohm each, cluster total 0.33ohm, = 36A load
MF ematches, 3x in series: 0.8ohm each, cluster total 2.4ohms, = 5A load

This 7x reduction in current load was exactly what I was looking for. By wiring a number of these series strings of MF ematches in parallel, it would be possible to reliably fire very large clusters on a typical club launch system. After posting this initial result on rocketryforum.com, Greg Dyben of Rocketflite contacted me about doing some more testing on these new MF’s, and I agreed.

Making MF ematches is a simple process for the flyer. The 12” long MF wires already have the nichrome soldered on. Dip the wires in pyrogen and dry for one hour. Then dip in sealer and dry for another hour.
(please see making Rocketflite MF (MagFire) ematches farther down on the right)

Testing Overview

Tests of Rocketflite MF prototype ematches all used:
> Currently available MF pyrogen.
> Nichrome wire is soldered to the lead wires.
> Almost all were prototype 26awg insulated lead wires.

Tests experimented with:
> What battery and electronics are used to fire the MFs.
> What the MFs are used to ignite.
> Variations on how much MF pyrogen dip is applied.
> Slight variations on details of the nichrome wire.

 
Ground Tests

Test: Can MFs Ignite AP Engines?    YES

> Ground test fired a variety of AeroTech reloads for the RMS 29mm 40-120 engine system:
   3 Black Jacks, 3 Redlines, 2 Blue Thunders, and 5 White Lightnings.
> For every test where the MF ematch head was in direct contact with the propellant,
   the engine fired on the first attempt.
> The one ignition failure was due to an intentionally tiny ematch head being placed so high in the
   G71-4R cavity that the head was entirely in the delay cavity above the propellant.

Conclusions:
> MFs can reliably ignite small AP engines of multiple propellant types.
> MFs (or any other igniter) need to match the 5/8” pyrogen length used by AT’s igniters to avoid the
   risk that a smaller ematch/igniter head could pass above the propellant grain in some 29mm
   engines.

Test: Firing MFs with Altimeters and Timers:
YES   if firing circuit is battery powered
NO  if CD (Capacitive Discharge) firing circuit

> For all altimeter tests the MF ematch heads were placed in small 0.17” ID tubes to simulate
   containment effects present in normal use.

 I used the Perfectflite Hi-Alt 45K altimeter and MF ematches for all flight ejection charges in 2008 and fired all 15 charges successfully.

Can MFs be Fired in LARGE Groups?   OH YES !

The following ground tests used a 12V launch ignition system with a 22Ah lead acid battery, 40A relay and 16awg wire.
 

* Comparison of approximate current loads with a strong 12V source, ignoring transient effects for simplicity. MF typical resistance 0.8 ohm, ML typical resistance 1.0 ohm.

Some MF’s that were not contained in tubes when fired burned part, but not all of their pyrogen. MFs ignite their pyrogen so quickly that a modest level of containment improves their ability to completely burn their pyrogen. Never saw partial pyrogen burn in any MF fired in a small 0.17” ID tube, always all or nothing. Modest containment would normally be present by design in ejection charges or 29mm or smaller engines.

Conclusions:

A strong 12V source can:
> Fire a single series string of 6 MFs.
> Fire multiple series strings of 3 or 4 MFs, when those complete strings are then connected in
   parallel.
> Longer series strings use less current because their resistance gets higher. However, if the string
   gets too long reliability becomes a problem.
> MFs ignite their pyrogen so quickly that a modest level of containment improves their ability to
   completely burn their pyrogen. Test: Varying nichrome size. Slight variations in the length and
   gauge of the nichrome did not significantly change test results.

More Flight Tests: Clusters and Deployments using Rocketflite MF Ematches

At the 4/19/08 CMASS launch in Amesbury, MA:

Flight 1: the TOGinator
Loaded with 26x D11-P engines. At 468 Ns total impulse,
this was a mid-I power BP liftoff.

The MF ematches were set up in 8 strings of 3 MFs in series plus 1 string of 2 MFs in series. Confirmed resistance / continuity: 1) when making MF’s, 2) after assembling the series strings, and 3) again after inserting the MF’s in each engine and before connecting the 9 series strings of MFs in parallel. Every resistance check was good every time.

Comparing ignition system current load, ignoring transient effects for simplicity: For this flight using MFs in series strings of 2 or 3, the total launch system load was about 48A. Using a typical igniter like the Rocketflite ML all in parallel, the total launch system load would be about 310A.

Also used MF’s to fire the two ejection charges using a Perfectflite HA45K altimeter.

The liftoff was dramatic, with the jets of flame spread wide, big cloud of smoke, and every engine firing! The rocket lifted off quickly due to the 160 lb thrust spike at the beginning of the 1.8 second engine burn, and reached an altitude of 765 ft.

All 26 engines fired, as did both ejection charges.

photo by Tony Vincent
picture 1

picture 2

picture 3

Making Rocketflite ML (Magnelite) igniters:

Step 1: Dip ML wire into ML pyrogen.


Step 2: Let dry for one hour.

Igniters are ready to use for motor ignition.

Making Rocketflite MF
(MagFire) ematches:

Step 1: Dip MF wire in MF pyrogen.

Step 2: Let dry for one hour.

Step 3: Dip in MF sealant.
(Included in MF kit)

Step 4: Let dry for one hour.

Ematches are ready to use for ejection charges and motor ignition.

 
The TOGinator getting prepped and then all wired up at the pad about to fire 26x D11-P engines with a parallel and series setup of
Rocketflite MF prototype ematches. Lifting off on a fan of flame and smoke.
Thanks to Jim Flis for the flight photo and the many cool FlisKits that inspired this rocket.

Flight 2: The Ultimate FireBall
Loaded with a 7x AP engine cluster made up of AeroTech 29mm engines: 4x F40W’s and 3x G77R’s.
Total impulse for the flight was 635 Ns, full I power using 29mm LEUP free engines.
The 4” diameter rocket was 7.5 ft tall and 9.3 lbs at liftoff.

                                                                                                                                            photo Guillaume Meriaux
The Ultimate FireBall wired with a parallel and series setup of Rocketflite MF prototype ematches firing 7x 29mm AP engines.

All engines fired, sending the rocket soaring to 1676 ft on a cool looking rose colored flame with a white core, due to the red G’s and white F’s. Both ejection charges fired for good dual deployment recovery on a Top Flight Recovery 5 ft Crossfire chute.

MF ematches fired the engines set up in 2 series strings of 2 MFs and 1 series string of 3 MFs, and also fired the two ejection charges.
The MF’s in series only required about 20A, compared to a parallel igniter load of about 80A.

The only difference in the preparation of the ematches for their different roles in these successful cluster flights, was that the MFs intended for BP engine ignition and ejection charges were dipped about 3/8" into the pyrogen (that is how long their heads were) and the MFs used to ignite AP 29mm engines were dipped about 5/8" (matching the head length of AT's igniters).

Rocketflite prototype MF ematches made it possible to fire everything 100% successfully with one type of ematch:
7 AP engines, 26 BP engines and 4 ejection charges.

Tests: Instant AP ignition

Using AT 29mm G64W engines, I experimented with adding small pieces of Blue Thunder propellant, pressed BP, or Rocketflite ML pyrogen, successfully achieving near instant engine ignition with all three methods. For all these tests I lightly sanded the inside of the propellant slot first. With the BT, used a thin strip jammed inside the G64 propellant slot. Pressed BP was a 1/8” thick slice of a 13mm Estes engine core, placed inside the space above the propellant and below the delay. The Rocketflite ML pyrogen, about 2x what would go on an igniter, was placed inside the top of the propellant slot.

First I evaluated the speed of ignition by attaching an LED light to the pad ignition circuit in parallel with the MF ematch and video recording the launches. By counting the video frames at 30 per second, I could see that all three methods had the G64’s up to pressure within 0.1 second. Without “extra help” a G64 typically comes up to pressure in 0.3 to 0.5 seconds.

Six way Applewhite saucer drag race "test"            photo Tony Vincent

Later I set up a 3 way and a 6 way drag race, with augmented AT 29mm G71R’s getting off the pad faster than BP powered saucers due to the raw power of the engines. Testing also revealed that BT located above the propellant was not effective, and that larger amounts of ML pyrogen were not necessary.

The method I prefer to boost AP ignition speed is Rocketflite ML pyrogen, as that poses the least risk of over pressurizing the engine.

Now I was ready to fire mixed engine types in clusters with confidence that all engines would be firing before the rocket started to rise up the launch rod.      

J and K Impulse Clusters

At NERRF 4 (6/20/08-6/21/08) used MF’s with
100% success to fire 12 BP engines, 6 ejection charges and 11 AP 29mm engines

including:
> VooDoo Daddy twice: including Paul's first cluster
> Apollo Saturn V twice: first for my L2, second a K impulse cluster
> Ultimate FireBall on a 7x G cluster

The Saturn V went up fast on a 5 engine K impulse cluster, with a Cesaroni K-445 and 4x G64's. Used a Rocketflite ML igniter for the center motor and MF igniters in the G64's. Worked like a charm, kicking all five engines instantly for a hard long thrust to 3,372 ft. Total impulse 2095 Ns.

The Ultimate FireBall went up on a J powered cluster of 7x RoadRunner G80-10’s, ignited by MF's. Fast smoky liftoff to 2462 ft.

               Apollo Saturn V cluster                          Ultimate FireBall prepped with MF ematches..................and lifting off fast                   .
.

At CMASS on 10/4/08 the FlisKits inspired TOGinator flew again. The upper body had been rebuilt to 4” diameter to share the ebay forward with the Ultimate FireBall and improve recovery reliability. The TOGinator also had gained four more engine tubes and was now prepped to fly with a 30 engine J powered cluster of 3x G71R + 12x E9 + 15x D11-P engines.

.                                                                                                                                          photo Doug Gardei                            photo Doug Gardei
Series strings of 3 MF ematches ready to be inserted into rocket engines. The TOGinator wired up with 30 MF ematches set up in series and parallel. At the pad another wire was run to the upper engines.

The flight lifted off on a wide fan of yellow flames cut through with three longer spikes of red, soaring to 1260 feet, mid-afternoon on a clear cool day. This was the flight I had been working up to for nearly a year.

The propellant slots in the Redlines were lightly sanded, and there was a small amount of Rocketflite ML pyrogen at the top of the slots, causing them to come up to pressure at the same time as the BP engines.

The MF's fired in every engine and both ejection charges. Three of the D engines did not ignite because (I discovered later) there was clay in the nozzles covering the BP, so 27 engines fired. Prepped with 910 Ns, fired 856 Ns, still a mid J powered cluster of AP and BP engines.

MF ematches fired the engines set up in 8 series strings of 3 MFs and 3 series string of 2 MFs wired together in parallel, and also fired the two ejection charges. The 30 MF’s in series/parallel only required about 65A from the launch system, compared to a parallel igniter load of about 360A.

At a later launch, the 10" Cluster Saucer got a good liftoff fired by MF's on the same 3x D11-P engines that had not fired in the TOGinator flight, after the clay in their nozzles had been carefully removed.

At the CMASS 11/1/08 launch the VooDoo Daddy went up for a 2 staged and clustered flight on 16x D engines:
280 Ns  H  impulse all BP flight.

The rocket lifted off straight up with a quiet hiss and a thick cloud of smoke to reach 1316 ft.

Fired all 16 engines in both stages plus the ejection charge.
This rocket has now burned 80 engines in 9 flights,
firing every engine every time using Rocketflite ematches (in 2008) and igniters (in 2007).

Test 30awg MF Prototypes for 18mm & 24mm AP Engines
 

In July Rocketflite sent me one batch of prototype MF’s using twisted pair 30 awg insulated leads. These are a good size for smaller motor nozzles. This first test batch of thinner 30awg MF’s have been used 11 times in 18mm & 24mm AT engines, resulting in 10 good ignitions and one ematch continuity failure. 5 White Lightnings, 3 Black Jacks and 2 Blue Thunders have been fired. All references to MF’s before and after this paragraph use 26awg leads suitable for slightly larger engines.
 

2008 Flight Summary

As a practical and fun way to field test Rocketflite’s 26awg prototype MF ematches,
I used them for every ejection charge, BP engine, and 29mm AP engine flown in 2008.

 2008 flying season results using prototype Rocketflite 26awg MF ematches:

> Ejection charges: 15 attempts / 15 successful

> 148 engine ignition attempts, of these:
* 142 fired on the first attempt
* 3 had clay covering the BP in the nozzle and were fired later after this was removed
* 1 was an old stubborn F21W, which confirms that a hard to light engine likes a long firing igniter
* 2 were engines in good condition that did not fire due to apparent failure of the MF ematch

Engine ignitions (BP and AP): 144 attempts with engines in good condition / 142 successes.

Bottom line, Rocketflite prototype MF ematches provided 99% reliability in the field.
The MF ematches achieved this performance while requiring much less current than typical igniters.

2008 lessons learned firing MF ematches

A single MF can be fired by one AA alkaline 1.5 volt battery, allowing the most basic launch system to fire anything up to a 29mm AP engine.

Small clusters of MF’s may be fired by 6V to 9V ignition systems. Ground testing an ignition system is a good idea prior to flying clusters. 

Large clusters should be fired by a strong 12V ignition system with a relay.

•  Rocketflite ML igniters or MF ematches can be used in parallel for up to approximately 8 engines

•  Combine series and parallel MF’s for clusters to reduce ignition current load. Have fired 26-30 MF’s at once, 60+ should be possible.

•  Secure wiring – no whip clips

Also consider:

•  Sand propellant slots – remove oxidation

•  May accelerate ignition with ML pyrogen at the top of an AP engine’s propellant slot
 

Disclaimer

Please note that I do not speak for or represent Rocketflite. Rocketflite has sent me supplies for tests.
What I have written describes my tests and projects as an individual rocketeer.

Please see www.rocketflite.com for more information.