modified Scion

[rfuss]

Built a handful of estes, almost all stock design except 1 or 2 with minor mods (serperation point, E engine mod).
Giving a shot at a decent bit of changes to a Scion kit.

Taking the 29mm MMT and changing to a 38mm.
Using all 4 fins given instead of the 3 designed for.
Adding an aeropack retainer cone.
Setup the coupler to be an Av bay.
Add substial amount of nose weight to compensate for the retainer, extra fin, aft movement of the motor, etc. Av bay would offset this some maybe but that looks to be around the Cg already.

For now planning on single deploy, but leave options open to modify in the future to be dual deploy. More likely that'll I will get a chute release and do things that way.
ORT file is a modfied one, belive Ke'tesh made the original. Changed up the fin tabs, MMT, have somewhat changed to the aeropack retainer but don't have specs to fully do it.
I ordered a 38->29 adapter as that'll be the usage until chute release/dual deploy to keep altitude down. And need to use the this and built Argent for L1 possible L2 cert to open up more motor options.

Current tailcone on it is just a paper shroud template and the mmt a spare.







View attachment Estes Scion (9712) with 38mm MMT and BT.ork

 

[Flyfalcons]

That looks cool; the tail cone really compliments the sweep of the trailing edge of the fins. Did OR say that the design became less stable with the fourth fin? Seems that the extra stabilizing area would easily offset the weight of the fourth fin.

 

[rfuss]

Did OR say that the design became less stable with the fourth fin? Seems that the extra stabilizing area would easily offset the weight of the fourth fin.

I didn't check actually to compare the two. A quick guess would it is positive towards stability, as its just the light weight estes plywood and not much weight. I planned to use 4 from the start to that was a first modification to the file.
Having OR do a nose weight optimization on a decent H motor, came to 130g and was -0.2 calipers before it was added. Will have more to play around with that. And need to have a plane for it to be adjustable weights; probably something along the lines of an all-thread shaft in the nose for base weight and then add washers and nut to add to.

 

[bclark989]

And need to use the this and built Argent for L1 possible L2 cert to open up more motor options.

Very cool project, but I wouldn't go for an L2 on a PSII air frame (with the exception of maybe the J94 from CTI, but those are plugged so you would need to get the AV-bay set up). That being said, it will be a very cool rocket for the shorter, lower max/avg impulse H and I 38mm motors out there. I did my first L1 attempt on the 38mm 3g I55 from CTI. Super fun to watch a motor burn for 7 seconds in a rocket that size.

I would also suggest epoxying some lead shot into the tip of the nose as opposed to just steel washers just aft of the nosecone bulkhead. More bang for your buck, fewer moving parts. Or maybe do both. Epoxy in some lead assuming the minimum amount of nose weight you would ever need (say for an adapted 29mm G) and then install your washer system for 38mm flights.

 

[KenRico]

I ordered a pair of these , one for my friends birthday and one for myself .

We really enjoyed reading about the Patriot conversion , will do that or maybe even a mini shredder .

Will do a fiberglass wrap on the tube and either sleeve the fins or fiberglass them too ..if we do a Patriot may do a Tip to Tip and have the layed fiberglass match the paint line ...or maybe try to do the tailcone.

Will keep this 29mm ..will grab another if 38 is desired ..at $30 its almost the same price as the aeropack retainer !

Kenny

 

[rfuss]

Very cool project, but I wouldn't go for an L2 on a PSII air frame (with the exception of maybe the J94 from CTI, but those are plugged so you would need to get the AV-bay set up). That being said, it will be a very cool rocket for the shorter, lower max/avg impulse H and I 38mm motors out there. I did my first L1 attempt on the 38mm 3g I55 from CTI. Super fun to watch a motor burn for 7 seconds in a rocket that size.

I would also suggest epoxying some lead shot into the tip of the nose as opposed to just steel washers just aft of the nosecone bulkhead. More bang for your buck, fewer moving parts. Or maybe do both. Epoxy in some lead assuming the minimum amount of nose weight you would ever need (say for an adapted 29mm G) and then install your washer system for 38mm flights.

Thanks for the advice for how the airframe could handle. I know its on the lower end of structural for big projects. I could glass it with a sleeve, do a colored FG or bicolor CF/Kev blend from soller. A surfboad I made with FG/CF twill came out pretty cool for pattern. More weight overall would add to it being a low and slow big rocket (a plus right now).

Retaining the weight will need some working, the lead shot is the go to. But with I want to change things up later or have more/less aft weight, I want the option to adjust it. Though Have this too over stable I don't think will be a big issue. I was imagining haveing a rod running from the nc bulkhead all the way to the tip, then add weight as far forward as possible along it. Maybe epoxy in a nut at the tip, all-thread screws in, then a nut washer on a substituted bulkhead into the cone and tighten down; tapered and internal will stop the lateral movement, the G force from a large motor likely will be an issue keeping it secure.

 

[rfuss]

I ordered a pair of these , one for my friends birthday and one for myself .

We really enjoyed reading about the Patriot conversion , will do that or maybe even a mini shredder .

Will do a fiberglass wrap on the tube and either sleeve the fins or fiberglass them too ..if we do a Patriot may do a Tip to Tip and have the layed fiberglass match the paint line ...or maybe try to do the tailcone.

Will keep this 29mm ..will grab another if 38 is desired ..at $30 its almost the same price as the aeropack retainer !

Kenny

Almost did the patriot after reading someone's work on that.
This will mostly before use on 29's, but to do the aeropack tailcone, needed to be a 38. So going that route with a adapter already planned to use.

 

[bclark989]

Thanks for the advice for how the airframe could handle. I know its on the lower end of structural for big projects. I could glass it with a sleeve, do a colored FG or bicolor CF/Kev blend from soller. A surfboad I made with FG/CF twill came out pretty cool for pattern. More weight overall would add to it being a low and slow big rocket (a plus right now).

Retaining the weight will need some working, the lead shot is the go to. But with I want to change things up later or have more/less aft weight, I want the option to adjust it. Though Have this too over stable I don't think will be a big issue. I was imagining haveing a rod running from the nc bulkhead all the way to the tip, then add weight as far forward as possible along it. Maybe epoxy in a nut at the tip, all-thread screws in, then a nut washer on a substituted bulkhead into the cone and tighten down; tapered and internal will stop the lateral movement, the G force from a large motor likely will be an issue keeping it secure.

Yeah, you could absolutely glass it. I haven't taken the plunge yet and tried glassing anything, so I forget about it when I start trying to dole out advice, haha!

Your idea for the all thread into the tip of the nose sounds cool too if you can rig it up securely.

If you end up executing on either of those ideas, please post pictures. I am working my way up the alphabet right now, but I imagine I will end up being one of the guys that settles into flying mostly G-J, so these types of construction techniques are great to read about and see examples of.

Cheers,

Brian

 

[rfuss]

Parts from the last order came in. Had several things to get for this an finishing up others. Thanks to Wildman and Countyline (even did a cash refund for some of the shipping), with eRockets delivery coming today.

Hvae run into an issue with the aeropack cone matting to the estes PSII tube. Was not aware of the lip on the tailcone, and which is almost exactly the same outer dimension as the outer dimension of the airframe.
So:
-abandon the aeropack cone and just make a shroud. the 38mm mmt tube is plenty long enough to do multiple centering rings and not need to worry about structural on the cone. need to order another retainer then.
-grind off the lip on the cone. easiest, but hate to modify a $40 part just to make it fit of a lower end bird, and likely cause issues if was used for other projects.
-glass the PSII. after done, cutout a 1/8-1/4" of the cardboard creating a small inner recess where the aeropack's cone lip will fit. after comparing the loc mmt tube to the estes airframe, the estes is very far from structural needs for higher motors. glassing would fix this issues but will create a lot more work. I'd done a decent bit of fiber/carbon work, but do not have any vacuuming material and do not want to financially get into that right now. So would be a basic laminate only, excess resin, thus even more weight. Back to the sim to see if doing so would make it unfeasible to fly with small motors. If so, would already have a 38mm mmt and worthy of a L2.