Estes doorknob upgrades

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lstmysock11

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Hi

I just ordered the 38mm motor upgrade kit with 38mm retainer for this kit. What other upgrades are worth doing? What motors can I run in this kit with out it being out of control. Or possibly add more weight if that will be a problem. I know the kit has plywood fins, that that is a big plus from what the kit has originally.
 

TigerHawk

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38mm motor is quite a jump in power for the Estes Doorknob Kit.
 

ThirstyBarbarian

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Most 38mm motors are going to be pretty big for an Estes Doorknob, even with plywood fins. I would think this size kit could fly pretty well on 29mm F and G motors with a 29/38 adapter. If you want to give it a try without buying motor hardware, there are some relatively inexpensive single-use motors that are sold in 2-packs. Depending on what it ends up weighing, some of these F motors could work: F20, F23, F27, F42, and F67, and they all ship without the added hazmat fee. The G74 is also sold in 2-packs but it requires a hazmat fee. The other single-use G motors to consider are G38, G40, G77, G78, G79, and G80 — all require hazmat.
 

ThirstyBarbarian

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The plywood upgrade puts this rocket right in the realm of mid-power rockets and makes it so it can handle the thrust and speed of composite motors, not just Estes motors. But I really don’t see it needing a 38mm motor mount. If they have a 29mm option, that would cover all the appropriate motors for a rocket thst size.
 

Adam3836

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May want to check your CG and possibly add more nose cone weight jumping to a 38mm more than likely will change things
 

lstmysock11

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Most 38mm motors are going to be pretty big for an Estes Doorknob, even with plywood fins. I would think this size kit could fly pretty well on 29mm F and G motors with a 29/38 adapter. If you want to give it a try without buying motor hardware, there are some relatively inexpensive single-use motors that are sold in 2-packs. Depending on what it ends up weighing, some of these F motors could work: F20, F23, F27, F42, and F67, and they all ship without the added hazmat fee. The G74 is also sold in 2-packs but it requires a hazmat fee. The other single-use G motors to consider are G38, G40, G77, G78, G79, and G80 — all require hazmat.


What 38mm to 29mm motor adaptor will work with this Estes kit? So this way I can use this better fin upgrade kit and use the 29mm motors.
 

David_Stack

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Might want to use the forum Search function… A quick query with the phrase “Doorknob build” turned up a number of dedicated threads.
 

dr wogz

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what retainer did you get?

I like the Aeropak retainers & adapters..

But like others have said: 38mm for this is big! I'd stick with the 29mm. pu-lenty of motors for this (and for your L1)
 

Back_at_it

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Hi

I just ordered the 38mm motor upgrade kit with 38mm retainer for this kit. What other upgrades are worth doing? What motors can I run in this kit with out it being out of control. Or possibly add more weight if that will be a problem. I know the kit has plywood fins, that that is a big plus from what the kit has originally.


38MM is a big jump and a bit of over kill but I like it. I built and fly one of mine on 29mm and thought those were overkill.

Besides the plywood fins and centering rings, I would definitely do Kevlar leader attached to the upper centering ring with a pretty good sized shock cord. Maybe 3/8"x 10ft.

Only other thing I would consider is doing a full length coupler to strengthen the tube. It will need to stop far enough down to allow for the nose cone shoulder. I did this on my 29mm powered Big Daddy and while it adds weight, it really stiffens up the tube.
 
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lakeroadster

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If I were building a model rocket that was named "Doorknob", I'd make a custom nose cone that looks like this..

1638201936506.png
 

lstmysock11

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38MM is a big jump and a bit of over kill but I like it. I built and fly one of mine on 29mm and thought those were overkill.

Besides the plywood fins and centering rings, I would definitely do Kevlar leader attached to the upper centering ring with a pretty good sized shock cord. Maybe 3/8"x 10ft.

Only other thing I would consider is doing a full length coupler to strengthen the tube. It will need to stop far enough down to allow for the nose cone shoulder. I did this on my 29mm powered Big Daddy and while it adds weight, it really stiffens up the tube.

I decided to go with the 29mm upgrade kit and I am also going to get and build the micro mamba from Mach 1. At least that should be a good flyer and can work on the smaller motors.
 

Back_at_it

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I decided to go with the 29mm upgrade kit and I am also going to get and build the micro mamba from Mach 1. At least that should be a good flyer and can work on the smaller motors.

Really impressed with their kits. Picked up my first one a couple of months back. Grabbed the Anti Gravity and it's in the build pile. Will probably do that one this winter.
 

lstmysock11

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Really impressed with their kits. Picked up my first one a couple of months back. Grabbed the Anti Gravity and it's in the build pile. Will probably do that one this winter.
They look really nice. Do you know of any other kits that are at least 2 inches and can fly using cheaper motors (LPR). So can fly and fly and fly and not cost 20 or more per motor and no hazmat. I know the doorknob can use with the estes adaptor 24mm motors in the 29mm engine mount. Looking for low power that is not minimum diameter rocket. If not I can just build a few minimum d rockets to get more flights for pretty cheap.
 

Back_at_it

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Sure. I'll start with Estes since they are the most common.

From the current catalog.
Explorer Aquarius. Challenging build but a great flier.
Expedition - Medium difficulty build.
Super Big Bertha.
Der Big Red Max.
Big Daddy.
Majestic

Others to consider. These are BT60 tubes which is 1.64 but they are still sizable rockets.

Big Bertha.
Citation Patriot.
Hi-Flier XL.

Quest Lil' Grunt.
Quest Quad Runner (now comes with a single 29mm mount).
DynaStar Stone Breaker.
DynaStar FireFox SHX
DynaStar Rising Star
LOC Onyx.
LOC Scout
LOC Star Fighter
LOC T-LOC 2.63"

There are a bunch of others that are worth tracking down from the last couple of years. Most are still reasonably priced and easy to find.

Estes Ascender.
Estes V2
Estes Executioner.
Estes Red Flare.
Estes Maxi Alpha III.
Estes Mammoth.
Estes Trajector
Estes Prowler.

Keep in mind that you can also buy Estes pro series tubes and nose cones directly from Estes and build you own upscale versions of pretty much any of the smaller rockets they sold. I just built a 2.0 inch Estes Ninja upscale and it flies great on the Estes E12 motor.

 

teepot

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The BT 80 Big Bertha with a 29mm motor mount was my first big rocket. It was the first of many larger rockets. That's a straight forward build. 2.6"diameter and about two feet tall. It will fly to 844' on an F 67. So a little lower on a D or E. A G80 puts it up to 1800'.
 

dpower

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<Soapbox>I don't quite get the attraction of starting with an Estes kit, adding a bunch of cost and weight, and tossing many of the parts. The final build will still have a fairly thin-wall body tube. Why not just get a LOC kit? These Estes Pro Series II kits built stock will handle the largest 29mm motor that fits. </Soapbox>

I regularly fly my stock 4" Mega Der Red Max on I200 motors. Only mod was rail buttons. Just finished the 3" Der Big Red Max, built stock - I'll have no qualms about flying it on G motors, other than wanting a big field, since it only weighs 12 oz.

Anyhow, I'm sure it'll be a nice rocket when done. The Vanderburn upgrade kits are very well done. Who am I to tell anyone else how to spend their money? 😁
 

pathtouch

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I got the upgrade kit from Rocketry Works mostly so I’d have more durable fins. The airframe and fin strength wasn’t a concern for me, but landing hard was. I want to launch it at the lake house on a frozen pond, which is quite unforgiven. I also wanted a better shock cord attachment option versus the elastic glued to tri-folded paper. So I ended up getting their optional 12’ Kevlar attached to the front centering ring. Finally a little extra weight is fine with me so I can keep altitude down.

Very happy so far, will post more pictures as build progresses.

92B38BA2-D640-49A8-AC03-106B51BF0CE3.jpeg

BAEACC93-A388-4FDC-A8D0-428C67D965ED.jpeg
 

steveh.jae

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Has anyone successfully made/launched a two-stage Doorknob? I see that James Weaver reported an underpowered smaller diameter version he attempted in the past but the launch was unsuccessful. Thinking a boostered Pro Doorknob might justify using a 38mm in the first stage. Thoughts?
 

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