# "New" Estes E Motor Length

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#### Dseter

##### Well-Known Member
OK, years ago Estes came out with an "E" motor and clip. They even made a thick, orange spacer to use in front of a "D" if you went with the new "E" clip. So I bought some E9-4 engines last week and went to the field to launch my Phoenix. I was patting myself on the back for having installed the "E" clip years ago in case I ever got some "E" engines and of course I load up and find that the new "E" is slightly longer than my "E" engine clip I installed years ago.
So of course now I am wondering if you folks know if Estes did indeed change their "E" engine length and if they have a new proper length E clip available- thanks!

#### RoyAtl

##### Well-Known Member
yes, the original estes E engine, the E15, was indeed shorter than the current E9 motor. The E15 appeared for a short time, but was plagued by production problems that wouldn't be noticed until the motor was a few months old. I.e. a fresh motor would work ok, but a motor that sat around for more than 6 months would almost certainly experience a cato. The NAR certification was withdrawn from the motor and Estes withdrew the motor from the market. The E9 replaced it a few years later.

#### Dseter

##### Well-Known Member
OK, cool, kinda figured that, drats. Question now is can a fella get a current "E" engine mount or the clip by itself? Thanks btw for the quick reply!

#### bradycros

ou can get the 3.75 in engine hook (estes E9 motor) at balsamachining.com. They are $0.60 each. #### Dseter ##### Well-Known Member Alrighty then, cool thanks. I'll have to load up on some. Is there a new spacer in case you wish to fly a "D" size? #### TheAviator ##### Well-Known Member Alrighty then, cool thanks. I'll have to load up on some. Is there a new spacer in case you wish to fly a "D" size? Yep. They sell one, or the centering ring from an Alpha works as well. If you're cheap and/or lazy, just fly an E, then cut 1" off the top with a saw. That'll work just as well. #### bradycros ##### Well-Known Member Well I don't know what the old measurment was, but I do know the current one. The E9 is 24mm wide, same as the D12. The E9 is one inch longer. So in a E9 motor mount you will need a 1 inch spacer to hold a D12 in place. #### MarkII ##### Well-Known Member Alrighty then, cool thanks. I'll have to load up on some. Is there a new spacer in case you wish to fly a "D" size? A 1" long coupler or a section cut from a spent D12 or E9 can be used. Personally, I prefer to use something other than a 24mm diameter coupler or motor case because they can be hard to extract when you want to put in the longer motor. I try to use something that will fit loosely enough to slide back out on its own while still being large enough in diameter to do the job. A 1" long section of BT-40 or a coupler for ST-8 or ST-8F will work. Semroc sells all three. The couplers are good for maybe three firings unless you coat them with something like epoxy. BT-40 is the cheaper way to go, since you can just buy a length of it and cut off 1" sections as you need them. An 18.5" length of BT-40 from Semroc is all of$1.75. That will give you 18 spacers. Just as with the couplers you can optionally make the BT-40 sections more durable by brushing on a coat of epoxy that has been thinned with acetone.

Now stay tuned - someone will no doubt advise you to just put a masking tape thrust ring around the aft end of the D12.

Mark K.

#### dpower

##### Well-Known Member
Now stay tuned - someone will no doubt advise you to just put a masking tape thrust ring around the aft end of the D12.

Mark K.
Nope - A thrust ring will work fine, but a spacer of some sort is still a good idea, or the top 1" of the motor tube will get gunked up with ejection residue, making it difficult to put an E9 in.

#### MarkII

##### Well-Known Member
Nope - A thrust ring will work fine, but a spacer of some sort is still a good idea, or the top 1" of the motor tube will get gunked up with ejection residue, making it difficult to put an E9 in.
Good point.

Mark K.

#### Handeman

##### Well-Known Member
TRF Supporter
Nope - A thrust ring will work fine, but a spacer of some sort is still a good idea, or the top 1" of the motor tube will get gunked up with ejection residue, making it difficult to put an E9 in.
You could just make the motor tube as long as a D motor, don't bother with the engine clips, use a tape thrust ring on all motors and tape them to the motor tube for retention. All problems solved.