CTI L2 Motor Stock

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mccordmw

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Sadness is seeing that the motor you want for L2 cert at MWP14 is out of stock at Apogee with no ETA and a caution that it can take up to a year. :( Do any other vendors participate in the CTI certification special where you can get a free casing with your motor on cert attempts?

I could have Wildman bring one for on-site purchase to save me the ~$30 hazmat fee, but that free $116 case is a great deal from the CTI cert special.

Backup plan: I already have a 54mm 4G case. I could just buy a lower level L2 motor to fit that one on-site.

... but daddy needs a new free casing! :)
 

rc dude

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Wildman does the cert special as well, I used it for my L2. I think all CTI vendors do it.
 

mccordmw

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Wildman does the cert special as well, I used it for my L2. I think all CTI vendors do it.
Ah that's good news. I just couldn't find any mention of it. I found a couple other vendors via Google that offered the special. If I can get Wildman to bring my stuff to MWP, that's all the better.
 

djs

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As CTI 54mm motors are pretty hard to get, you could also do a 38mm J with an adapter.
 

kidrobo

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Are they doing the cert specials anymore? When I was getting my L2 stuff everyone I had talked to was not doing it. This was right after that fire they had /: maybe that has changed now.
 

tbonerocketeer

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Wildman does the cert special as well, I used it for my L2. I think all CTI vendors do it.
I did, though I'm. It right now since cti production is very limited. It's not cost effective to buy hardware, give it away and wait until product is available to get it replaced. That ties up money on a product I cant sell(it's gone) and can't replace(nothing to get it shipped with).i do still have a decent selection of cti reloads in stock though.
 

djs

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mccordmw- I can loan you whatever CTI hardware you need, if you were just going to get a case for the cert flight. Except the 54-6XL.. I don't have that one yet :)
 

rc dude

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If you can't find a casing in time, you can use my 54mm 6gxl, just pay shipping.
 

BDB

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Check out AMW Pro-X. Jason, our on-site vendor, did it for my L1.
 

mccordmw

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mccordmw- do your L2 on an L935 imax! :)
I'm not brave enough to break mach with my Binder Design Excel. I'm sure the kit is strong enough and of good enough quality. I just don't trust who built it (me). :p
 

crossfire

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If nothing else I am sure someone in your club has a good motor stash that you could get a motor from.
 

markkoelsch

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If you are doing it at MWP why would you not buy from Wildman? He is onsite, and you skip hazmat costs.
 

CzTeacherMan

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I've got a 54-6XL that will be available to borrow. Standard hardware borrowing rules apply.
 

scsager

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If you are doing it at MWP why would you not buy from Wildman? He is onsite, and you skip hazmat costs.
I was in Wildman's Trailer this past weekend... He has *some* CTI 38mm J motors in stock.

It's totally free to call him to see if he can hook you up! (815) 638-3200
 

Nick@JET

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You should call Wildman asap, 54-6grain stock is dwindling due to the CTI issue. I just bought a K711 and they are running thin. Maybe he has a secret stash somewhere though
 

Thorfire

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I recall them giving all of their cti stock to amw before ldrs. I bet the site doesn't have inventory tracking.
Gary had a couple cti 54mm L motors at the Tripolli MN launch earlier this month. You'd be best to call or email him.
 

watermelonman

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Or a L265 Mellow :)
Everyone who uses that one here ends up disappointed, even on a totally purpose built rocket, unless using it as a sustainer.

It simply needs more initial thrust. Similarly I want nothing to do with the L395, and judging by supply no one else wants it either.
 

markkoelsch

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Everyone who uses that one here ends up disappointed, even on a totally purpose built rocket, unless using it as a sustainer.

It simply needs more initial thrust. Similarly I want nothing to do with the L395, and judging by supply no one else wants it either.
Considering the weight of the motor itself you need a light rocket to make it work well.

It might be a really good candidate as the basis for a boost-sustain modification. A grain of white thunder would likely solve the issue.
 

mccordmw

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Considering the weight of the motor itself you need a light rocket to make it work well.

It might be a really good candidate as the basis for a boost-sustain modification. A grain of white thunder would likely solve the issue.
The rocket with no motor is 6lb. With the motor, it's a beefy 11.4 lb. If I launch from an 8' 1010 rail, it sim with a speed off the rail of 19.4 m/s. I usually shoot for a speed that is 4x the wind to be safe. The sim looks decent for it. The TTW is a bit short of my preferred 6:1.

Flight calculations:
Motor: CTI 54mm 6GXL L265 MY
Stability calibers: 1.36
Thrust-to-weight: 265 N / 5.18 kg = 5.2:1
Velocity off rail (8’): 19.4 m/s (43.4 mph)
Max acceleration: 80.3 m/s2
Max velocity: 268 m/s (599 mph = mach 0.80)
Apogee: 3,010 m (9,875 ft)
 

djs

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While it's entertaining for us in the peanut gallery to think of your L2 on an L motor (hey- it's not my rocket- do what you want), you probably would be safer doing it on a smaller motor. MWP is 3 days, so if the L2 goes well, you'll have time to do another, higher flight on the same rocket?
 

mccordmw

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While it's entertaining for us in the peanut gallery to think of your L2 on an L motor (hey- it's not my rocket- do what you want), you probably would be safer doing it on a smaller motor. MWP is 3 days, so if the L2 goes well, you'll have time to do another, higher flight on the same rocket?
I gotta pass the written Tripoli test first. :p

I'll probably go with whatever stock I can get that's a 54mm 4-grain since I already have that case and there isn't a good selection of other motors from vendors that still have the cert special. I'm not too concerned about the L265 being too stressful compared to the other motors. It maxes out at mach 0.8 which is inline with the other motors in my selection range. If I pick a motor that is slower so as to not stress the frame, the speed off the rail starts to cross the 15 m/s range, which makes me nervous if there's any appreciable wind.

The main challenge with the L265 would be tracking it up to 10k. The Eggfinder GPS I have in it seemed to work really well, so I'm not too worried. If I do go with the K160, speed off the rail is still an OK 16.1 m/s. Apogee is about 6800'.
 

ChrisAttebery

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I would NOT trust the L265 in a 10 lb. rocket. My 6.5 lb. minimum diameter rocket weathercocked pretty badly on that motor. It deployed at ~300 mph because the rocket had turned into the wind so much.

If you can find a K740 they are a kick in the butt. By far the best 54mm 4 grain reload IMHO.
 

mccordmw

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I'm hearing too many red flags from people far more experienced than me. :) I have an idea! I'll stay away from the longburn for L2 cert! Brilliant!

A K740 puts me at mach 1.02. Call me a chicken here, but I'll stay away from something that puts me at transonic to mach. I'm looking at some 4-grains with nice acceleration and decent altitude.

I'll limit myself to what I can have brought there by Wildman in the 3-4 grain range so I can avoid hazmat. Lemme see...

4 Grain
K160 - too low avg. thrust
K520 - Hmm. Maybe. Speed off rail = 26 m/s. Max vel. = mach 0.89 (I don't like transonic). Apogee = 6,300'
K940 - B'caw! I'm too chicken for such a high thrust motor. :p

3 Grain (but I need to buy an adapter)
J140 - too low avg. thrust
J449 - I like how BS come off the rail fast. Speed off rail = 25 m/s. Max vel. = mach 0.78. Apogee = 5,240'
K360 - Another good choice. Speed off rail = 20 m/s. Max vel. = mach 0.74. Apogee = 5,350'
J760 - White Thunders make me nervous with a 230 m/s2 acceleration. Skip. Speed off rail = 32 m/s. Max vel. = mach 0.87. Apogee = 5,090'

Of all those, I think the 3-grain K360 looks like a good, non-stressing flight. Not too much acceleration, but enough speed off the rail and average thrust to keep it pretty straight in moderate winds.
 
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