This may weathercock... just slightly [ASP Rocketry Tall Boy Kit]

[Joshua F Thomas]

 

[rharshberger]

Actually it will....a lot! A Mean Machine's Stability is in the neighborhood of 12-13 iirc and they weathercock lots too. Use a hard hitting motor to get them off the pad as quickly as possible.

 

[GalantVR41062]

Use lead to fill the fin can, would help with the stability but would make it unflyable.

 

[Joshua F Thomas]

Yeah, that's kind of defeats the purpose, lol

 

[Nytrunner]

If I was flying it, I'd try and keep the margin between 47 and 25cm (15to 8% of length). Right now you're at....~21%

 

[MOF410]

I have a tall boy im building now and multiple mean machines. I've always enjoyed the mean machine flights and I'd be lying if I said I wasn't nervous about the tall boy.
Will post videos when I get it in the air, maybe next club launch.

 

[XrayLizard]

Weathercocking.... I duck and cover when I see a Phoenix on the pad lol!

 

[BABAR]

People always talk about stronger motors (which makes sense, although the mass may be counterproductive).

What people don’t mention is using the longest rail possible.

 

[Joshua F Thomas]

Indeed, this kit normally has you use a regular 3/16” rod. This seemed slightly crazy to me, so I have installed both lugs and 1010 rail buttons on my Tall Boy.

Getting the buttons installed together with the engine mount was a real PITA, but it should be worth it.

My Tall Boy is getting finishing paint and I’ll be launching at my next club meet later this month. Should turn some heads.

I’ll be trying an E30-4 for the first flight.

 

[jrap330]

Weathercocking.... I duck and cover when I see a Phoenix on the pad lol!

Yeah surprisingly my Estes Phoenix flies straight...it is the AMRAAM that weathercocks occasionally..

 

[XrayLizard]

Mine flew absolutely sideways

 

[jrap330]

Mine flew absolutely sideways

Could be you built in heavy..epoxy......papering fins......and therefore needed more nose weight than clay Estes provided. Seen numerous videos of others people's Phoenix and flies fine

 

[XrayLizard]

so long ago.. was probably just windy..lol

 

[rharshberger]

Yeah surprisingly my Estes Phoenix flies straight...it is the AMRAAM that weathercocks occasionally..

AMRAAM's dont weathercock....they landshark.....

 

[Joshua F Thomas]

Follow up, this flew excellently. The light weight made it jump off the pad and it deployed a little after apogee, came down great on both parts. Was very happy with it.

I'm going to add an extra rail button toward the top, as the thing pulls always from the rail toward the end and gets pushed about by any wind.

 

[MOF410]

How far up were u thinking for the 3rd button?

Mine is primed just waiting for time to paint. Went w lugs and buttons for laumch gear. Im really excited to fly. It looks preposterous in full form.

 

[Joshua F Thomas]

So I have done this, and I put it on one of the middle segments. It will then work for any of the combinations that use the bottom segment and a middle segment; that is, the 3 part or 4 part configuration.

 

[Joshua F Thomas]

The bending in flight is kinda hillarious

 

[OzHybrid]

Assuming it was straight when you launched it, what you're seeing is a demonstration of Eulers buckling load in action. The nosecone is the largest frontal area and as the speed increases the load on it increases. The motor pushes on one end of the thin rod and the wind load on the nosecone on the other.

https://en.wikipedia.org/wiki/Euler's_critical_load
Easiest demonstrated with a straw. If you have it vertical and add load it supports the load until it collapses. It bends first but when long thin things are loaded from the end dynamically the collapse happens real quick. Add the frontal load to a long rocket and a small gust of wind from the side and Ta Ta .

Great photo, though you probably don't want to kick it much harder with the motor choice.

 

[OzHybrid]

The maximum buckling load is right in the middle. If you can join the middle sections together permanently, you won't have a slip fit join in the worst possible place.