CTI reload does not fit into casing, help please

[billdz]

I was excited to receive my first CTI motors and casings today, until now I have only used AT. But after working with the CTI components for hours, I'm ready to give up, either I'm doing something wrong or the parts are defective. The plastic motor liners simply appear to be too large for the casing. With some force, I can get the motor into the bottom of the casing, but I can't get it high enough to screw in the aft closure. And it is really difficult to remove the motor, even though it is only partially in. I've tried a little sanding of the plastic motor liner and a small spray of WD-40 on the inside of the casing, but neither helped. This can't be right, can it? I've seen videos of CTI motor assembly where the motor slipped right into the casing with no resistance at all. What am I doing wrong?

 

[BEC]

It might help to know which motor and which case.....

 

[mpitfield]

The liner and reload can be tight, however what you are describing does not sound right. Are you sure your hardware is not deformed in anyway?

 

[dhbarr]

Is the hardware new, or used? If used, with a bright light ensure there is no plastic slag in the aluminum case.

 

[tim cubbedge]

One thing I do before I even attempt to load a CTI 38mm motor is coat the case with silicon spray. Was the motor sitting in sunlight for any length of time? I usually have no problems if I assemble in shade or at home. Do you have a CTI vendor on site? He will help. Where do you fly?

 

[iqsy59]

I can honestly say that I have NEVER experienced that. Aerotech...yes, but a simple removal of a layer of paper does the trick. CTI, never ever. Any chance to provide photos of case and liner, including inside of liner?

Cheers,
Michael

 

[billdz]

Thanks for the replies. This is a brand new Pro38 casing and 1G 38mm motors (G50 and G58), same issue with all 3 motors. They just arrived yesterday via FedEx. They were never in sunlight since they have been in my possession. The spacers slide into the casing with no problem but not the motors. The casing is not deformed and there is no slag or other material on the inside of the casing. There is no CTI vendor at the launch.

 

[tim cubbedge]

Pictures please - how far EXACTLY does the liner extend out of the case?

 

[billdz]

Here are a couple of pics. It is a 3G liner, using 2 spacers with the 1G motors. When inserting the motor, there is a lot of resistance at the point of entry (the threaded portion of the casing). Once the forward part of the motor is past the threads, it starts to go in more easily for a bit but then stops completely about 3/8" short of where it needs to go. If I pull on the motor, the plastic aft closure comes off with the plastic liner just inside the bottom of the casing, with the liner covering the threads, as shown in the last pic. When in this position, the motor is difficult to remove from the case.

I tried WD-40 but not silicon spray, is that better? I was thinking about placing the casing in hot water to expand it a bit, but that should not be necessary, I hope.

 

[djkingsley]

in the middle picture you can see the scrap marks on the liner where it is deformed from the delay grain, I would take some sand paper and remove that hump.

 

[tim cubbedge]

Silicon is all the vendor at my club uses and all I have ever used. Maybe not be your problem though. Dunno. I'd take it to a vendor and let him try to see what's going on. What ever you do, do not try & force it.
By the way - where are you launching these days with all the burn bans?

 

[Q-Aero]

",,,,but then stops completely about 3/8" short of where it needs to go"


3/8" is about the curved part of the spacers, are you shure you put them in the right way ?

 

[iqsy59]

A little confusion with the middle photo. It appears that the aft end of the motor is oriented with the fore end of the case. Probably just how it is laid out for the photograph?

Cheers,
Michael

 

[claytonbirchenough]

",,,,but then stops completely about 3/8" short of where it needs to go"


3/8" is about the curved part of the spacers, are you shure you put them in the right way ?

This. Check to make sure your spacers are the right way. Both curved sides should be towards the top of the casing, opposite of the nozzle.

 

[billdz]

After applying a lot of sandpaper to the liner and some silicon spray to the case, I finally got the motor in. I hope this is not usual with CTI motors, which are supposed to be easy to assemble. The spacers are correctly placed with the rounded sides facing forward.
@Dennis - I believe the sandpaper was the major factor in getting the motor in. I have 2 other motors that were equally sticky and I'll have to do the same to them.
@Tim - The burn bans are putting a damper on my L2 plans. The April launch of the Spacecoast club was canceled, last week's Ft. Myers club launch was canceled, and the same for tomorrow's NEFAR launch. I'm now hoping to test at the May 20 Spacecoast launch, but it is doubtful in light of the dry weather. So far the Broward, Palm Beach, and Miami/Homestead launches have not been affected, but they do not allow L2 motors. I'll try my new CTI G motors tomorrow at the Broward launch.
@Michael - Yes, I had it reversed in the photo.

 

[djkingsley]

I have had maybe 2 out of nearly 100 of CTI motors I have flown need to be sanded like that.

 

[Kallahan11]

I've had 1 CTI motor that was sticky like that, I ended up taking off the nozzle and forcing the rest of the casing in with a spacer, flew fine.

 

[rstaff3]

I have one 38 and two 24mm CTI cases and have never personally seen this. I'd be more worried about getting the plastic liner out after use than the motor firing right.

 

[billdz]

@Kallahan - A spacer, great idea. I also took off the nozzle but could not think of a way to get any leverage on the liner to press it in, a screwdriver so close to the threads seemed too risky.
@Dick - Yes, it was hard to remove the liner on my last flight, with an AT reload and casing, I'm worried the same thing will happen with this one.

By the way, I also ordered a 6XL casing and motor from the same vendor, these fit much better, the motor slid right in. Only the three G motors are too tight.

 

[cerving]

I've flown at least 100 CTI loads, and with the Pro38's it's pretty much standard procedure that you'll have to remove the nozzle and use a spacer to push the liner into the case. You'll definitely want to lightly lubricate the liner with silicone grease before you install it. The other thing you need to be careful about is that you don't cross-thread the plastic nozzle threads... if you can't get about two turns using two fingers then something is wrong. Don't force it.

 

[Kallahan11]

@Kallahan - A spacer, great idea. I also took off the nozzle but could not think of a way to get any leverage on the liner to press it in, a screwdriver so close to the threads seemed too risky.
@Dick - Yes, it was hard to remove the liner on my last flight, with an AT reload and casing, I'm worried the same thing will happen with this one.

By the way, I also ordered a 6XL casing and motor from the same vendor, these fit much better, the motor slid right in. Only the three G motors are too tight.

I had my issue eith a 6xl for the record. Also i had no problem getting the liner out after firing. With nothing on the inside the case is very flexible.

 

[Bat-mite]

I have had a similar problem with a CTI 38. Do not modify the motor in any way or you will void your warranty. Return it to your dealer ASAP.

 

[markjos]

I've flown at least 100 CTI loads, and with the Pro38's it's pretty much standard procedure that you'll have to remove the nozzle and use a spacer to push the liner into the case. You'll definitely want to lightly lubricate the liner with silicone grease before you install it. The other thing you need to be careful about is that you don't cross-thread the plastic nozzle threads... if you can't get about two turns using two fingers then something is wrong. Don't force it.

+1 to this. Pushing with a spacer against a hard surface (nozzle removed) is the ticket, and I've had to do it many times. As Cris says, don't force the plastic aft closure - make sure that the liner is fully seated in the case before threading the closure.

Mark

 

[Wayco]

I've had a couple of 6XL loads that were hard to install. Both were at launches that were supported by AMW/ProX. Robert helped me and showed me a couple of tricks, including using the spacer to press it in. Silicone lubricant works better than WD-40, not sure why...
It looks like the delay grain deformed the forward part of the liner, I hope this is not another CTI problem. Sharon assembled two 38mm reloads yesterday, and several more 29's, no problem with any of those.

 

[Steve Shannon]

If you're comfortable disassembling the reload assembly I would recommend peeling a layer of paper from the top grain casting liner rather than sanding the outer plastic insulating liner. It may be easier. While you have the grains out of the plastic insulating liner see how well it slides in.
It may just be that you have an out of spec motor case. Check your reloads against someone else's cases at a launch sometime.


Steve Shannon

 

[Banzai88]

If you're comfortable disassembling the reload assembly I would recommend peeling a layer of paper from the top grain casting liner rather than sanding the outer plastic insulating liner. It may be easier. While you have the grains out of the plastic insulating liner see how well it slides in.
It may just be that you have an out of spec motor case. Check your reloads against someone else's cases at a launch sometime.


Steve Shannon

The scuffed area is right at the o ring on the delay grain module. I've been seeing this sort of thing more and more often with my own reloads since the 'recall' for the funky plastic. It's not unique to the replacement delay grains, but only seems to happen with recall and post recall batch lots.

 

[Titan II]

This is a previous post regarding lube.....


Jeroen_at_CTI Jeroen_at_CTI is offline
Senior Member
Join Date
26th April 2009
Posts
563
Quote Originally Posted by CarVac View Post
What sort of spray?
A "Silicone Spray". If you Google that, you will find lots of options. It does not build up. It is very thin. Some examples:
- Permatex 80070
- Liquid Wrench M914
- WD-40 Specialist Silicone Lubricant (note: not regular WD40).

Jeroen



I use this and all loads slide in, and thread in, easily.

 

[jimzcatz]

To all you naysayers, I have had to sand the crap out of a few cti loads. I once had a pro54 3grain that took me an hour to get it out after flying. It happens.

 

[cbrarick]

get a 5/8 inch dowel on your way out. unscrew the aft closure then feed the dowel in from the forward end and push! all will pop out.

 

[Coop]

I have run into this a few times over the years--not often enough to fret about, but I do keep some sandpaper in my range box just in case...


Later!

--Coop