7.5” Sumo Upscale Build

[tjsnakez]

I’m back! I’ve had this idea for a while - but it’s finally time to do it!

The Aerotech Sumo was my first rocket I flew high power with when I was 11 - I was also a huge fan of the Gates Brothers upscale Sumo growing up of course. So naturally I wanted to build a big Sumo!

I am using a PML 7.5” phenolic glassed with a soller composites sleeve and a 4oz finishing layer, 3/8” ply fins, 1/2” ply rings, and possibly the very last 7.5” PML glass nosecone (thanks Jesse Ulibarri!).

In the spirit of the Gates Brothers’ big Sumo, I am doing a single 75mm and four outboard 38mm for the motor configuration. If I can get my $hiz together I’m going to try and have this ready for LDRS! Braden and Shane will be at my house in exactly 1 week to build our next big Airfest project so I have my work cut out for me!

First flight will be on a K1800ST to test recovery and witness the whole flight. If all goes well I plan to put it up at Airfest on an M1297 and two J350 - air starting two more J350 at 8 seconds

 

[loopy]

That sounds like a fun project! can't wait to see more of this come together!

 

[techrat]

You're going to have that done by LDRS? That's 3 weeks.... Less than 3 weeks away. I assume the paint will still be drying while it's in the car.

 

[tjsnakez]

You're going to have that done by LDRS? That's 3 weeks.... Less than 3 weeks away. I assume the paint will still be drying while it's in the car.

I’m going to try! No promises though! Haha next week we are going to speed build a 100lb rocket as well. Rockets everyday after work for the next 2 weeks!

 

[loopy]

I’m going to try! No promises though! Haha next week we are going to speed build a 100lb rocket as well. Rockets everyday after work for the next 2 weeks!

AGG seems to love to build big heavy projects in a week...lol

 

[ThePlmbr]

Good-luck. I love a large Sumo! Greg Olson

 

[tjsnakez]

Slots cut and a dry fit! Making progress!

 

[tjsnakez]

Electronics hatch

 

[rfjustin]

Planning on glass fin to fin?

 

[tjsnakez]

Planning on glass fin to fin?

Keep going back and forth on this. Doesn’t really need it to stay together, but I might put a layer on there for durability with the swept fins.

 

[loopy]

Keep going back and forth on this. Doesn’t really need it to stay together, but I might put a layer on there for durability with the swept fins.

At the very least, maybe a FG strip over the external fillet. I have an upscale Estes Sizzler that started to get cracked fillets from landing on the big rear swept fins, so I sanded it all down and put FG strips over the fillets. No issues since.

 

[tjsnakez]

Fin can is assembled - I proceeded to do internal fillets on everything after I took this picture. I should have it in the airframe tomorrow night.

I ended up getting a piece of 3/8” polyethylene tubing to use as igniter conduit from the electronics hatch to the aft CR for air starts. And it didn’t occur to me when I drilled the hole for the conduit that there would be an outboard motor there (duh!) - luckily the polyethylene is flexible

 

[StreuB1]

And it didn’t occur to me when I drilled the hole for the conduit that there would be an outboard motor there (duh!)

Ahhh.....been there, been there.

Great idea on the PE tube though for a conduit!!! NEVER thought of that! Dirty cheap as well.

 

[tjsnakez]

Ahhh.....been there, been there.

Great idea on the PE tube though for a conduit!!! NEVER thought of that! Dirty cheap as well.

What’s funny is it was an accident that I ended up with the PE tube since everywhere was out of small aluminum tubing. Needless to say it worked out in my favor! I’ll probably continue to use PE in the future as it’s dirt cheap and flexible which is a plus haha

 

[bunkermonkey9]

Excited to see how this turns out

 

[StreuB1]

What’s funny is it was an accident that I ended up with the PE tube since everywhere was out of small aluminum tubing. Needless to say it worked out in my favor! I’ll probably continue to use PE in the future as it’s dirt cheap and flexible which is a plus haha

 

[Jeremy Sim]

Great Project!!!

 

[DMehalko]

Awesome, love the sumo, what are you going to be using for the 2 different rounds of airstarts?

 

[tjsnakez]

Fincan is in the airframe and fillets all done at once.

 

[tjsnakez]

Awesome, love the sumo, what are you going to be using for the 2 different rounds of airstarts?

The current plan is to use a Raven 4.

 

[Neutronium95]

This looks great, I'm looking forward to seeing it at LDRS. Any plans for future motor combinations? The last time the Gates Brothers Sumo flew it was on a mix of Blue Thunder and Mojave Green motors, which made for an awesome flame and a crazy screech.

 

[Hobie1dog]

 

[tjsnakez]

This looks great, I'm looking forward to seeing it at LDRS. Any plans for future motor combinations? The last time the Gates Brothers Sumo flew it was on a mix of Blue Thunder and Mojave Green motors, which made for an awesome flame and a crazy screech.

I’d like to do an all redline flight and an all blue thunder flight! All lit on the ground. Also a redline/blue thunder mix to make a huge pink flame would be cool.

 

[StreuB1]

I’d like to do an all redline flight and an all blue thunder flight! All lit on the ground. Also a redline/blue thunder mix to make a huge pink flame would be cool.

(4) I600's and a central K1000.

 

[3stoogesrocketry]

A L900 and 4 I280's all popped on the ground would be nasty.

 

[tjsnakez]

A L900 and 4 I280's all popped on the ground would be nasty.

I’d probably swap the I280s for I327s, but can’t go wrong with a sparky cluster!

 

[tjsnakez]

Update on the big Sumo!
Braden and I had our hands full sanding the big Arcas before we left for LDRS - so I just didn’t have time to finish the Sumo even though it was structurally complete.

I just need to put on the decals, figure out the recovery, and put on rail buttons/motor retention hardware!

First flight will now be at Airfest on a K1800ST. I really want to see the recovery on the first flight since I am using a ARRD style release tether. This will be the first time using it, and I’d like to see the recovery sequence before I send it to 12,000ft. Estimated altitude on the K is 3800ft so it should be super impressive in a different way - it should make a hell of a whistle!

 

[Pinetree]

Dude.. how about some video?

 

[tjsnakez]

Dude.. how about some video?

I have video - just need to edit. Hopefully soon

 

[Pinetree]

Yay!