Bad Luck or bad motor at LDRS41

[Glasspack]

So, I find myself humbled and embarrassed yet again, in this often, UNFORGIVING hobby.

I went for another flight of my SA-14 archer at LDRS41 on Sunday and needless to say it went badly.

I have to assume someone from this forum may have seen it… well at any rate, I will include the edited video for your review. I was hoping to get some feedback from people like you with more experience.

The rocket prep was pretty normal except for one thing…… This is the first time I had two of the grain cartridges fall out of the sleeve when the motor rolled off the table. The FWD grain was pretty obvious as it has the pellet in it to aid with ignition. An igniter won’t go through it so I knew that was the FWD Grain, Concave end with the pellet towards the Delay grain. The other one however was the same as the middle one and I assumed the two flat ends of the grain butt up to each other. So, I put it in the sleeve with the concave end facing the nozzle in the AFT closure. The delay was adjusted down to 7 seconds and the assembled motor loaded.

(By the way: I did get a very fast response back from CTI after I emailed them a few days ago, So I know now that the Concave ends all face FWD. And ONLY Classic Propellent have BOTH ends of the gain cartridges concave shaped. Also possibly the first igniter may have consumed the pellet...making the motor not ignite properly on attempt #2)

So back to the launch…… The first igniter burned out without motor ignition…. it’s never happened with any of my other CTI Motors, but, I didn’t think too much of it. Inserted a new Wildman Igniter and went for attempt #2. The LCO hit the button and it took about 2-3 seconds for it to smoke and then it sputtered on the pad for almost 13 seconds total, just throwing sparks. Finally, it built pressure and lifted off the pad. I have to assume it did not have normal thrust as it left the rail it arced backwards and headed over the parking lot and crowd (fortunately to the Right OUT of harms way.) the model impacted the ground a few hundred yards away and destroyed itself on impact. I KNOW the deployment charge fired... I think just fractions of seconds before impact.


I will tell you CTI seems to have good customer service !

So, did I have a bad motor or just **** luck?

 

[Charles_McG]

I think this was just as I was leaving to tend the winery - was the LCO egging it on, urging it to light?

You didn't specify the motor - but just once have I had a problem with CTI ignition on the pad - depending on the igniter, it can fit through the hole in the pellet and burn above it. I'm more careful with marking the insertion depth on the wire now.

None of the motors, CTI or otherwise, that I have seen doing an impersonation of a road flare on the pad have turned out well. Under thrust and under impulse once they get underway. They use up a lot of propellent in flare-mode.

 

[green dragon]

odd - I have NEVER had a CTI motor misfire when the igniter fired.

Sounds like maybe the head of the 'starter' went through the pellet as noted and lit the delay grain instead ? still odd the pellet would not ignite from topside.

As for the concave ends - if manufacturer says it makes a difference, it must in some way, but only thinking imho would be concave end forward helps with flame propogation and quick ignition - a Bates grain motor should have alal grain ends burnign once lit and should be neegligable on performance....

Sorry about the flight, looks like it was a nice rocket.

 

[3stoogesrocketry]

It sounds like your match head turned sideways and went in-between two grain surfaces. That is why it took so long to ignite, it lite the middle of the motor. It only took off when the flame front finally touched the pellet and that pressurized the motor.

 

[ChicagoDave]

It sounds like your match head turned sideways and went in-between two grain surfaces. That is why it took so long to ignite, it lite the middle of the motor. It only took off when the flame front finally touched the pellet and that pressurized the motor.

I saw the flight and I concur with this assessment -- in fact I remember commenting on how long the motor chuffed on the pad before building up pressure. I would say the most likely explanation is the starter did not reach the top grain, causing the chuffing.

 

[Glasspack]

Thank you all for your inputs........... I have talked to Cesaroni a few times in email about this.
Even shared the video of the launch with them. I was happy to hear him tell me it would not be my fault for flipping the aft fuel grain around 180 degrees.
The company is still working with me on details. I am very happy to have such good customer support. This is the first time I have had a weird performance from a CTI Pro-38 (Overall I am very new still) Nice to get your inputs and learn from ALL my good or Bad results.

Dave, 3Stooges, Charles did you fly at LDRS ? My son may have some photos for you

 

[Charles_McG]

Dave, 3Stooges, Charles did you fly at LDRS ? My son may have some photos for you

An upscale Photon Disruptor on Thursday morning that had chute separation.

The 1/5 scale Black Brant 11a three stage [attempt] on Friday.

I tried a PSII Series Cherokee-ish kitbash on Sunday - but ran into igniter problems, and despite Frank Nobile's best efforts, I had to pull the rocket and get back to open the cidery.

 

[Glasspack]

Charles,

I am pretty sure this is your Black Brant

View attachment _DSF9430.JPGView attachment _DSF9432.JPG

 

[Charles_McG]

Yep.

 

[n3tjm]

To me it looks like the motor had the wrong nozzle. To large a throat opening would cause chuffing, slow ignition, and anemic performance.

 

[ECayemberg]

Looks like a Public Enemy Archer; lots of forward fin area!

What was the loaded weight of the rocket?

 

[3stoogesrocketry]

To me it looks like the motor had the wrong nozzle. To large a throat opening would cause chuffing, slow ignition, and anemic performance.

There appeared to be little to no chuffing. Just a steady stream of sparks, kinda cool looking. I will agree the motor was a little anemic, but that is simply because it dumped half its total impulse on looking cool on the pad. I really think this one just comes down to improper igniter placement, we have all been there.

 

[Glasspack]

Well I thank all of you for your inputs and thoughts........... I value the knowledge and experience of others.
I have some time now that my wife is home after surgery and I have a few days off to care for her.

I am going to try and salvage a few parts from the SA-14 Archer and I wanted to share a few more photos
from the carnage ..... I think you will all agree its NOT really a good choice for a repair.

I bought a heat gun to try to remove the Aeropack 38mm retainer first.......

From what I can tell...... I Believe it hit the ground very fast within a second of deployment charge firing.
The nose cone appears to show serious signs of a hard hit....not really deformed, but missing paint.
The rear fins dug into the earth and ripped off, check out the dirt/grass stuck in the back end.
The FWD section had the coupler & bulkhead torn almost off but the chute and most of the cord is undamaged.
The upper Airframe had the zipper looking damage from the wide nylon shock cord pulled backwards.

What ever happened, it was below the tree line as we could not see it ! I knew it was not gonna be a pretty sight !

I am very glad it went to the right of the crowd !!!

Any way Thank you again, please comment and give me YOUR feed back on the pictures of the damage.

Thank you Cesaroni for the great customer service. As of the last email they are going to replace the I180SK

 

[Glasspack]

There appeared to be little to no chuffing. Just a steady stream of sparks, kinda cool looking. I will agree the motor was a little anemic, but that is simply because it dumped half its total impulse on looking cool on the pad. I really think this one just comes down to improper igniter placement, we have all been there.

Looks like a Public Enemy Archer; lots of forward fin area!

What was the loaded weight of the rocket?

It IS an OLD Original Public Enemy Model. I got the Kit years ago on Ebay......... It has a very intimate history with me and my first High Power mistake....
and subsequent rebuild. It weighs in at just over 5 lbs. I think..... It has always flown very nice...….. It breaks my heart to see it like this. I will forever be gratfule it did not injure any one or anything on this last flight...… one hundred yards to the airfield left and it could have been WORSE.

 

[Glasspack]

Perhaps a new model from Wildman will soothe my wounds.
Of Course, with my Rocksim file; it would be an easy rebuild !!!

 

[Handeman]

Perhaps a new model from Wildman will soothe my wounds.
Of Course, with my Rocksim file; it would be an easy rebuild !!!

The way I see it, you still have the nose cone. Just need a new BT, MMT, a couple CRs and some ply for the fins and it should be a quick rebuild. The hard/expensive part will be the decals....

Good luck with the rebuild.

 

[Glasspack]

The way I see it, you still have the nose cone. Just need a new BT, MMT, a couple CRs and some ply for the fins and it should be a quick rebuild. The hard/expensive part will be the decals....

Good luck with the rebuild.

Thank You Handeman......

But I am gonna take my wifes
advice and build something else.....

My Archer will always be dear to my heart. It was afterall.....my first.




HPR that is.....








This is what the Skidmark Launch was supposed to look like


R.I.P. Girl