Planning to clone the Astron Falcon, any tips?

[Retrospace101]

Hi there,so I’m thinking of cloning the Estes Astron Falcon (K13) boost glider, however, I’m not sure exactly which “type” (thickness, etc.) of balsa to build it with. I’m also a bit unsure if I have to Airfoil the wings, or if I can just leave the balsa “as is”.

 

[the random rocketer]

If you need a 1/1 scale Semroc has them. SEMROC FLYING MODEL ROCKET KIT HAWK™ KV-65
Otherwise JimZ has the plans. Use basswood for the spine as they tend to break on the first launch.

 

[Stewman]

The original plans used 3/32" balsa for the wings and they are airfoiled. The fuselage is 1/16" and I agree with the above, it's pretty flimsy. Hope that helps.

 

[shockie]

put 1 degree negative incidence in the tail... the original Estes version had a 0-0 incidence and it tended to death dive into the ground.... the Renger original had a auto-stab setup that estes deemed too difficult for modelers of the time to be able to do....

 

[BABAR]

Add a small carbon fiber rod or strip to the fuselage. Won't add much weight, but will reduce chance of breakage.

 

[Retrospace101]

Add a small carbon fiber rod or strip to the fuselage. Won't add much weight, but will reduce chance of breakage.

Thanks, where do you think I get some at that size?

 

[GuyNoir]

put 1 degree negative incidence in the tail...

Tail incidence has to be VERY precise or the model will loop under power. I instead put 2 degrees of positive incidence in the wings. Since they're closer to the CG, the moment arm is shorter, the incidence angle can tolerate some sloppiness (but not much), and the looping tendency is reduced.

 

[BABAR]

Thanks, where do you think I get some at that size?

Check local RC hobby store.

A brief search shows this on Amazon

https://www.amazon.com/uxcell-Carbo...=p_85:2470955011&rnid=2470954011&rps=1&sr=8-3
With prime shipping so gets to to you fast

You can co cheaper on ebay but last thing I got cheap took about 1.5 months to arrive!

 

[hcmbanjo]

put 1 degree negative incidence in the tail... the original Estes version had a 0-0 incidence and it tended to death dive into the ground.... the Renger original had a auto-stab setup that estes deemed too difficult for modelers of the time to be able to do....

I met Larry Renger at NARAM 60. He told me that story.
My Semroc Hawk fuselage broke during boost on it's second flight. The break was right above the stabilizer and rudder area.
I glued it back up and reinforced that weak area with two toothpicks. The clay weight was for balance.

 

[shockie]

Tail incidence has to be VERY precise or the model will loop under power. I instead put 2 degrees of positive incidence in the wings. Since they're closer to the CG, the moment arm is shorter, the incidence angle can tolerate some sloppiness (but not much), and the looping tendency is reduced.

I met Larry Renger at NARAM 60. He told me that story.
My Semroc Hawk fuselage broke during boost on it's second flight. The break was right above the stabilizer and rudder area.
I glued it back up and reinforced that weak area with two toothpicks. The clay weight was for balance.

View attachment 446413

I talked with Larry Renger (via email) extensively about his Sky Slash nee Falcon design back in the early 21st century. He send me a few drawings and pictures of his early BG work, including his FlaminGo, and his original Sky Slash... One of these days before I croak I'm planning to try and write up an article with that information so it won't be lost to history. Maybe even offer some kits of his designs. we'll see.

 

[shockie]

Hi there,so I’m thinking of cloning the Estes Astron Falcon (K13) boost glider, however, I’m not sure exactly which “type” (thickness, etc.) of balsa to build it with. I’m also a bit unsure if I have to Airfoil the wings, or if I can just leave the balsa “as is”.

https://jhaerospace.com/product/sky-slash-ii-boost-glider-60-scale/https://drive.google.com/drive/folders/1JdWPymGh56IaIk3VS6TG0kO0pbb3Yfna

 

[tab28682]

I have always thought that a small change to the Falcon design would make it more foolproof for the average modeler.

Add spring loaded elevators held back via a burn string. Best technique would be small music wire torsion springs embedded in the hinge line

Allows optimum boost trim and would be more foolproof and easier to trim for glide.

Only downside would be the end of the burn string trailing along.

I lost the first and only one I ever built back in 1969. Boosted into the glare of the sun and I lost track of it. Searched the large field for hours and never found it. Sigh.

 

[BABAR]

I have always thought that a small change to the Falcon design would make it more foolproof for the average modeler.

Add spring loaded elevators held back via a burn string. Best technique would be small music wire torsion springs embedded in the hinge line

Allows optimum boost trim and would be more foolproof and easier to trim for glide.

Only downside would be the end of the burn string trailing along.

Replace burn strings with #16 rubber bands.

The elastic keeps them tight, they are strong but burn through just about instantaneously, and they fall free of the rocket once burned.

 

[Retrospace101]

Replace burn strings with #16 rubber bands.

The elastic keeps them tight, they are strong but burn through just about instantaneously, and they fall free of the rocket once burned.

Thanks again. Just a quick question: What are Burn Strings? ( I believe it has something to do with burning?)

 

[Ez2cDave]

Tail incidence has to be VERY precise or the model will loop under power. I instead put 2 degrees of positive incidence in the wings. Since they're closer to the CG, the moment arm is shorter, the incidence angle can tolerate some sloppiness (but not much), and the looping tendency is reduced.

Also, 1 degree of Pod down-thrust can be beneficial.

Dave F.

 

[BABAR]

Thanks again. Just a quick question: What are Burn Strings? ( I believe it has something to do with burning?)

A piece of thread which is positioned preflight in front of the motor along the course of hot ejection gases at deployment, the rest of the thread holds helicopter rotors or glider wings or elevator positions in the closed or folded configuration for boost.

At (hopefully) apogee ejection charge fires, burns the string, and releases the rotors or glider wings or elevators to open up (basically reconfigure) the model from a “rocket” during boost to a “helicopter” or “glider” for recovery.

Personal note: I haven’t seen any models using a burn “string” where elastic thread or a rubber band wouldn’t work better.


Scroll to paragraph 4 under construction

https://archive.rocketreviews.com/reviews/all/qcr_high_rotor_helicopter_95.shtml
Here’s my version

 

[tab28682]

I should have typed burn elastic thread, instead of burn string, as that is what I actually use.

I have never had any issue with the elastic thread failing to burn through on any of my heli models.

Will have much more time for modeling in a couple of weeks. Might have to build a Falcon and do the spring loaded elevator mod.