Contrail hybrid reloads

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Voyager
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Contrail hybrid reloads

Postby Voyager » Sat Mar 05, 2016 3:11 pm

Hi guys

Is anyone using Contrail hybrid motors? If so, what are you using instead of Pyrodex pellets for ignition?

Cheers
John
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Re: Contrail hybrid reloads

Postby karlbaum » Tue Mar 08, 2016 9:41 am

Hello John,

I fly Contrails but here in the U.S. I am able to get pyrodex pellets and so I use those. I am planning on experimenting with oxygen and steel wool to start hybrids. This is nothing new as it was used by West Coast Hybrids in similar sized motors. I do make GSE for this and am planning on having a website up and running with tutorials. So if you want I can point you in the direction of "pyro free" ignition. Otherwise you could use a piece of AP solid fuel to start your Contrail. Keep in mind that you will want your igniter placed away from the fill tube so that it does not burn a hole in the fill tube before it starts the AP fuel.

Karl Baumheckel

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Re: Contrail hybrid reloads

Postby Lister » Tue Mar 08, 2016 2:57 pm

I have no experience with hybrids but I know a few people that use the nitrocellulose ping pong balls for igniting hybrids.. also know people that use oxygen and steel wool.

L

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Re: Contrail hybrid reloads

Postby Voyager » Wed Mar 09, 2016 10:18 pm

Thanks for the tips guys.

I have looked at the hybrids that use GOX, but I am trying to avoid the extra GSE required for that. I have considered using a piece piece of AP, which is what I use in my Rattworks I90 hybrid motor, but I thought that there may be a good reason why you shouldn't do that with the Contrail. I can't think why I couldn't use AP.

That's a good point about the igniter position, Karl. Burning a hole in the fill tube before the AP ignites would waste N2O and possibly delay ignition of the main grain.

I have also read about the nitrocellulose method, too.

John
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Re: Contrail hybrid reloads

Postby PK » Sat Mar 26, 2016 11:37 am

    Slice of Blue thunder (or other catalysed) propellant (more is gooder)

    Pressed BP.

    Copper thermite (can be tricky to get right, too much will lift the piston and make a new nozzle in the case wall)

    Pressed candy (use very fine KNO3).

    If you reroute the vent through the piston and enlarge it to 0.5mm then you can just pack steel wool in and use a regular igniter.

Remember it's less about the amount of heat you put in and more about the rate that you put that heat in.
One way to get high rates of heat is to preheat the whole fuel grain so that it can conduct that heat quickly into the NOX when it flows. However you are better off going for a fast burning comp.

My personal favorite is a mix with a very high 'n' value. It'll burn fairly slowly until the pressure spikes as the NOX in the fill line dumps into the CC, then it will burn fast and vaporise enough liquid for a quick light..
PK

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Re: Contrail hybrid reloads

Postby Voyager » Tue Mar 29, 2016 10:20 pm

Thanks for the tips PK. I have a few Blue Thunder reloads so I'll slice some up and give them a go with the Contrail when it arrives. I have been using slices of BT & White Lightning with my Rattworks I90 with good results.
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Re: Contrail hybrid reloads

Postby jase » Tue May 24, 2016 7:55 pm

G'day John have you had a chance to use the Contrail motor yet?
Me and my rockets run on Moonshine.

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Re: Contrail hybrid reloads

Postby Voyager » Sun Feb 26, 2017 9:47 pm

Oooops! My apologies for a very belated reply to that question jase! No, I haven't purchased the Contrail motor yet, I'm still using my Rattworks as I have quite a few reloads to get through. However, I am keen to move to the Contrail motors, particularly if the supply of Rattworks gear and reloads continues to be a problem.
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Re: Contrail hybrid reloads

Postby jase » Wed Mar 01, 2017 7:51 pm

LOL John thanks for getting back to me.

I'm reasonably confident we'll all be hearing a bit more about Contrail hybrids downunder this year :wink:

Really looking forward to seeing them ripping holes in the crisp Victorian air this year, and elsewhere as the case may be :D

Hope you are all well, looking forward to catching up soon.
Me and my rockets run on Moonshine.

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Re: Contrail hybrid reloads

Postby Voyager » Tue Mar 28, 2017 10:14 am

Just an update Jase ...

I have a 38 mm Contrail 36" motor & reloads on their way from the US. So, there will be some Contrail action in the skies of Ardlethan in May at CRGs 2nd HPR launch for the year, as well as the RATTworks. Hopefully, some of us might make it down to Serpentine this year, too. So, it is possible that there will be Contrail motors "ripping holes in the crisp Victorian air this year"!

Cheers
John
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Re: Contrail hybrid reloads

Postby Voyager » Sun May 28, 2017 11:33 pm

The Contrail 36"/38mm motor in a modified PML Gamma was successfully launched at CRG's HPR launch at Ardlethan today. An I210 reload was used with a slow nozzle size to achieve a 3955' apogee. This was acceptably close to the simulation apogee of 4300'.

For the information of those wishing to fly these Contrail hybrid motors, I used a 1 cm length of 29mm G76 grain as the ignition grain around the fill tube beneath the injector rather than the Pyrodex pellets (these are difficult to source here). The ignition was very successfully initiated with a FirstFire igniter plugged into the AP grain. I will be using an I333 reload next.

Looking forward to the 54mm Contrail when I'm ready to move up!
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Re: Contrail hybrid reloads

Postby CATO » Mon May 29, 2017 9:40 am

Congratulations on the successful launch "Voyager".
"In thrust we trust"

AMRS 21 L3

Impulse:
2017: 5,973 Ns (13.14% M)
Ns 16: 34,558; 15: 35,955; 14: 6,016; 13: 10,208
PB - Gorilla N2717WC, H: 10,260', S: 1.14M


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