38mm DoorKnob -

[Andy Greene]

So who's is gonna do it , the 38mm upgrade for your Estes DoorKnob with the Vanderburn upgrade ??
https://www.vander-burn.com/product/estes-doorknob-upgrades/20?cp=true&sa=true&sbp=false&q=false

 

[Andy Greene]

Im hoping someone else will tackle it before I start building- as of now Im going 29mm but being spoiled on flying 38mm research motors/ Im half tempted to do it.

 

[rharshberger]

Im hoping someone else will tackle it before I start building- as of now Im going 29mm but being spoiled on flying 38mm research motors/ Im half tempted to do it.

Not hard to do...getting it back might be! With a 38 MMT I would double the arframe using coupler sections from Balsa Machining Service, that way it would take many of the 38mm motors without much stress.

 

[Andy Greene]

I was really just amazed they even offered it as an option- even with the upgrade plywood and 29mm , on a G80 it should be a hoot

 

[ThirstyBarbarian]

Nice knowin‘ ya, Knob.

 

[3stoogesrocketry]

I thought the 38mm was awsome , so I'm in the process of doing a J250 SU 54mm Knob. Parts should be showing up soon.

 

[ThirstyBarbarian]

I thought the 38mm was awsome , so I'm in the process of doing a J250 SU 54mm Knob. Parts should be showing up soon.

In a modified Estes Doorknob? Yikes!

 

[Andy Greene]

Im thinking 5 inch glass tube and a 54mm mount - where is Gary T when you need him

 

[3stoogesrocketry]

In a modified Estes Doorknob? Yikes!

Yes . 54mm is perfect size for this bird . I'm thinking a K185 will push it right to the Potter waiver .

 

[Philip Tiberius D.]

I built one... need to dig up what motor she ran on. I have a second (unbuilt) with the Vander-Burn upgrade (love his stuff btw). I airframe buckled and fin sheared off but I believe most of that occurred on impact due to the ejection change melting the parachute cords. Aerotech G76 Mojave

 

[Philip Tiberius D.]

Data

 

[3stoogesrocketry]

The build has started. Motor shown is a 54mm 620ns I100 Firestarter . 6 seconds of terror. All the extra goodies are from Mac Performance .125 canvas cut by Nat Kinsley. Motor mount is also canvas , just not in the picture.

 

[Philip Tiberius D.]

The build has started. Motor shown is a 54mm 620ns I100 Firestarter . 6 seconds of terror. All the extra goodies are from Mac Performance .125 canvas cut by Nat Kinsley. Motor mount is also canvas , just not in the picture.

Is that a “stock” Doorknob with MacP fins or a all MacP kit ?

 

[3stoogesrocketry]

Is that a “stock” Doorknob with MacP fins or a all MacP kit ?

All Stock Estes Door Knob . Mac .125 thick fins and rings . Body tube will have a layer of 6 oz glass . Altimeter in the nose cone . Single deploy at the top with a long azzzz streamer. 7k on this I motor

 

[Andy Greene]

The build has started. Motor shown is a 54mm 620ns I100 Firestarter . 6 seconds of terror. All the extra goodies are from Mac Performance .125 canvas cut by Nat Kinsley. Motor mount is also canvas , just not in the picture.

Why canvas not
G10/12 ?

 

[3stoogesrocketry]

Why canvas not
G10/12 ?

I believe the canvas has enough strength for the job at hand . I know this material can handle mach 1 flights and it has been documented to be *almost* as strong as fiberglass.

 

[Tobor]

Canvas (0.769 oz/ft³) is also lighter then G10 (1.1 oz/ft³)/G12 (1.05 oz/ft³).

 

[Nytrunner]

You may not even need glass on the body tube. It has no joints, the motor mount and rings will reinforce it internally down where most of the stress will be, and the tube is just short (smaller bending moments)

 

[Andy Greene]

Canvas (0.769 oz/ft³) is also lighter then G10 (1.1 oz/ft³)/G12 (1.05 oz/ft³).

Not knocking it , but Im not sure I would be real concerned about the weight difference, I have just never worked with it . If it was a huge bit cheaper maybe, thats just me, if your putting that much motor to that little rocket-
whats a few ounces ??

 

[Flyfalcons]

No glass needed, the mmt and centering rings add a ton of strength. 54mm no problem.

 

[Andy Greene]

No glass needed, the mmt and centering rings add a ton of strength. 54mm no problem.

In a 3x18 carboard tube ??

 

[3stoogesrocketry]

[

In a 3x18 carboard tube ??

Correct , even though it will have a layer of glass for durability in transport and if it splashes down. The buckle load or column strength of two concentric tubes inside each other is very high .[/QUOTE]

 

[Flyfalcons]

In a 3x18 carboard tube ??

Worked in the Angry Daddy. Just make the stuffer tube long enough so a minimum of body tube is unsupported.

 

[Andy Greene]

So I finished mine up-it was fun to build a small cardboard/plywood kit again - I was getting spoiled on glass 4 inch stuff . Of course I changed the colors , mainly because it was what I had in leftover quarts , and Im not a big fan of the cardstock colors. Will give it a go in a few weeks on a G40/7W with the JLCR.

 

[messedupryan]

Of course I changed the colors

the green is a fantastic choice