L3 Fusion review.

firemanup

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Brief
This is a 5.5" by 90" cardboard and plywood rocket kit. 3FNC. It is advertised as a one-stop level 3 rocket kit with everything needed included to get your level 3 certification. Recommended M motors are the M1297, M1315, and M1350DMS.
2665859B-D386-478E-945E-A56CBE5FAC8E.jpeg

Components
For the most part the components are good quality paper/cardboard body tubes and couplers, plywood fins and centering rings and a plastic nosecone. Nosecone fit was very lacking and may have begun the demise of this kit when it flew.
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Construction
Instruction books are the what Binder kits are known for, you won't find better, this kit came with a detailed 14 page instruction booklet to include color photos and cut away views. It's a pretty straight forward build and then every thing gets double walled with the provided couplers to add strength.
I deviated slightly from the kit directions in the build of the booster section, in that I built it without the rear centering ring on so that i could apply ample interior fillets to the motor mount tube as well as the inside of the air frame. My directions have no mention of fiber glassing any parts. The directions call for double walling the airframe and then coating the inside of those couplers through out the air frame with epoxy to strengthen them. Directions also call for coating the outside of the actual joining couplers with epoxy as well.
I added to by tip to tip fiberglassing the fins, and then fiberglassing the inside of the actual joining couplers, payload to av bay coupler, and av bay to booster coupler.
594067B8-5F15-4F24-8944-4305507A90E9.jpeg
9E25B23F-BA74-4C43-A423-01D9E6EB3880.jpeg

667E4D94-A4A5-4573-B48F-784156D979BA.jpeg
Finishing
Finishing is very simple in theory and if you are good at applying complete vinyl wraps it's pretty easy. Paint the nosecone and bottom of the booster section white, then apply the one piece wrap over the entire rest of the rocket all at once.
I am not good at applying vinyl wraps, applying the wrap took over 90 minutes and i was never happy with how it went on, nothing was wrong with the wrap, it's just not something i'm good at, I would much rather paint and apply decals.
Construction Score: 3

Flight
Kit flew it's maiden flight at Kloudburst 29 in Argonia Ks with Kloudbusters. Beautiful sunny morning with lots of space so I started her off with what she was intended for, a cardboard rocket on an M motor. I had 2 M motors in stock, the M650 and the M1297. Was saving the M650 for a 4" bird so I went with the M1297 on this flight. I was aware that this kit had been shredded previously on this motor, however I was confident in my build and the strengthening additions i made, and having communicated with the kit designer several times during the build he appeared confident as well.
Flight went up, and toward the end of the boost she came apart, if you watch the video at about 23 seconds there is a shimmy in the smoke, watch it on a full size screen and slow it down to 1/4 speed and you notice over the next couple seconds something white flickering in the sun to the left side of the smoke trail, initially thought this was the nosecone, but it flickers, the cone is big and from any direction has ample mass to be visible the same, i'm now pretty certain that what is being seen is the wrap floating in the air, as it rotates you are bound to get the thin side pointed at you making it appear to disappear when it's that far away and hence flicker...
Recovered the booster section intact with only a broken fin due to a 5300 foot free fall, av bay damaged, and nosecone damaged, the payload bay, main recovery harness, and main chute were never found.
Flight Video here as well as some pictures of build and aftermath,

My feeling is that the vinyl wrap came off in flight as the rocket was approaching peak thrust around 900mph and that started a shimmy the small 2” coupler couldn't stabilize, the payload then shredded. Payload and booster were both vented with a1/8” hole, directions called for 1/16”.
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5FBA5979-D2B6-4E98-8CAF-C5E06AAB1412.jpeg
Summary
In summary not very happy. When a kit is designed to be a L3 rocket and touted as such, when built per instructions it should be able to do just that, especially when flown on the recomended motors. When the kit has multiple failures maybe the cause needs to be determined instead of continuing to market and sell the kit as something it might not be.
I spent a significant amount of money on this kit, i spent a VERY significant amount of my time on this kit, and significant money on the motor, I didn't do that for this end result.
I was very fortunate that I didn't lose the 2 altimeters and tracker that were on board as well.
I did lose an expensive kit, a parachute, recovery harness, and Aeropack retainer that is now affixed to a booster I can't use, though I may be able to salvage it.
Overall Rating: 2
 

crossfire

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Brief
This is a 5.5" by 90" cardboard and plywood rocket kit. 3FNC. It is advertised as a one-stop level 3 rocket kit with everything needed included to get your level 3 certification. Recommended M motors are the M1297, M1315, and M1350DMS.
View attachment 460694

Components
For the most part the components are good quality paper/cardboard body tubes and couplers, plywood fins and centering rings and a plastic nosecone. Nosecone fit was very lacking and may have begun the demise of this kit when it flew.
View attachment 460696
View attachment 460703

Construction
Instruction books are the what Binder kits are known for, you won't find better, this kit came with a detailed 14 page instruction booklet to include color photos and cut away views. It's a pretty straight forward build and then every thing gets double walled with the provided couplers to add strength.
I deviated slightly from the kit directions in the build of the booster section, in that I built it without the rear centering ring on so that i could apply ample interior fillets to the motor mount tube as well as the inside of the air frame. My directions have no mention of fiber glassing any parts. The directions call for double walling the airframe and then coating the inside of those couplers through out the air frame with epoxy to strengthen them. Directions also call for coating the outside of the actual joining couplers with epoxy as well.
I added to by tip to tip fiberglassing the fins, and then fiberglassing the inside of the actual joining couplers, payload to av bay coupler, and av bay to booster coupler.
View attachment 460697
View attachment 460698

View attachment 460699
Finishing
Finishing is very simple in theory and if you are good at applying complete vinyl wraps it's pretty easy. Paint the nosecone and bottom of the booster section white, then apply the one piece wrap over the entire rest of the rocket all at once.
I am not good at applying vinyl wraps, applying the wrap took over 90 minutes and i was never happy with how it went on, nothing was wrong with the wrap, it's just not something i'm good at, I would much rather paint and apply decals.
Construction Score: 3

Flight
Kit flew it's maiden flight at Kloudburst 29 in Argonia Ks with Kloudbusters. Beautiful sunny morning with lots of space so I started her off with what she was intended for, a cardboard rocket on an M motor. I had 2 M motors in stock, the M650 and the M1297. Was saving the M650 for a 4" bird so I went with the M1297 on this flight. I was aware that this kit had been shredded previously on this motor, however I was confident in my build and the strengthening additions i made, and having communicated with the kit designer several times during the build he appeared confident as well.
Flight went up, and toward the end of the boost she came apart, if you watch the video at about 23 seconds there is a shimmy in the smoke, watch it on a full size screen and slow it down to 1/4 speed and you notice over the next couple seconds something white flickering in the sun to the left side of the smoke trail, initially thought this was the nosecone, but it flickers, the cone is big and from any direction has ample mass to be visible the same, i'm now pretty certain that what is being seen is the wrap floating in the air, as it rotates you are bound to get the thin side pointed at you making it appear to disappear when it's that far away and hence flicker...
Recovered the booster section intact with only a broken fin due to a 5300 foot free fall, av bay damaged, and nosecone damaged, the payload bay, main recovery harness, and main chute were never found.
Flight Video here as well as some pictures of build and aftermath,

My feeling is that the vinyl wrap came off in flight as the rocket was approaching peak thrust around 900mph and that started a shimmy the small 2” coupler couldn't stabilize, the payload then shredded. Payload and booster were both vented with a1/8” hole, directions called for 1/16”.
View attachment 460702
View attachment 460700
View attachment 460701
Summary
In summary not very happy. When a kit is designed to be a L3 rocket and touted as such, when built per instructions it should be able to do just that, especially when flown on the recomended motors. When the kit has multiple failures maybe the cause needs to be determined instead of continuing to market and sell the kit as something it might not be.
I spent a significant amount of money on this kit, i spent a VERY significant amount of my time on this kit, and significant money on the motor, I didn't do that for this end result.
I was very fortunate that I didn't lose the 2 altimeters and tracker that were on board as well.
I did lose an expensive kit, a parachute, recovery harness, and Aeropack retainer that is now affixed to a booster I can't use, though I may be able to salvage it.
Overall Rating: 2

Sorry to see your fight report. You can get that retainer off in about 2 minutes. And you can use it on next project.
 

firemanup

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FT2FT???

The fin didn’t fail, don’t really understand the question?

The booster free fell from over 5000 feet and landed on that fin and snapped the ply wood just above the fillet. It’s advertised as 1/4” ply fins but the calipers show them slightly smaller that’s why I glassed them.
 
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ECayemberg

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Flight

My feeling is that the vinyl wrap came off in flight as the rocket was approaching peak thrust around 900mph and that started a shimmy the small 2” coupler couldn't stabilize, the payload then shredded. Payload and booster were both vented with a1/8” hole, directions called for 1/16”.

View attachment 460700

Hi Jason,

Sorry about the failure. I did inspect and witness a L3 flight with the L3 Fusion this weekend, so it's possible.

Did I read that right, and am I seeing the photo correct...is there only 2" of coupler joining the two sections shown above? Rule of thumb is one caliber or more, so I'd agree that that 2" interface is way too short and was likely a contributing factor to flight failure.

-Eric-
 

firemanup

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Hi Jason,

Sorry about the failure. I did inspect and witness a L3 flight with the L3 Fusion this weekend, so it's possible.

Did I read that right, and am I seeing the photo correct...is there only 2" of coupler joining the two sections shown above? Rule of thumb is one caliber or more, so I'd agree that that 2" interface is way too short and was likely a contributing factor to flight failure.

-Eric-

Yes you are seeing that right. 2”.

The flight you are talking about is John’s on an M650 correct? Not the same flight, much less G’s and 100mph less top end.
 

crossfire

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Yes you are seeing that right. 2”.

The flight you are talking about is John’s on an M650 correct? Not the same flight, much less G’s and 100mph less top end.
It's always been coupler should at least go into tube same as diameter of the tube. 5" tube 5" of coupler mimiun. But if cone come off first all bets are off.
 

firemanup

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It's always been coupler should at least go into tube same as diameter of the tube. 5" tube 5" of coupler mimiun. But if cone come off first all bets are off.

Yes I agree, but was wondering if I was learning something new, the variable being that coupler had 6 plastic rivets going through it.

I thought maybe that was enough to make up for the short coupler.

Either way, built per the directions and she didn’t work...☹️
 

firemanup

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I would do longer coupler and rivets or screws.

Yeh for sure if i were going to re do it, but i'm not. I've already invested too much time and money into that kit, that couldn't do what it claimed. I'll buy a loc big nuke 4 this fall/winter and do a cardboard M with that, or scratch build something.
 

firemanup

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Hi Jason,

Sorry about the failure. I did inspect and witness a L3 flight with the L3 Fusion this weekend, so it's possible.

Did I read that right, and am I seeing the photo correct...is there only 2" of coupler joining the two sections shown above? Rule of thumb is one caliber or more, so I'd agree that that 2" interface is way too short and was likely a contributing factor to flight failure.

-Eric-

Eric, here is the same bird you inspected last month that flew on the M650, flew this past weekend at Mini Midwest Power on an M1297, same result as mine, fortunately John was able to recover the payload bay, unlike me, and able to post mortem the rocket and it appears pretty clear that it folded over on that short 2" coupler.

Unfortunate.

 
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cwbullet

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It is a shame that a small M can do that to a kit meant to be for a level 3 flight. I overbuilt my level 3 significantly from the stock kit. It appears you did the same.
 

ECayemberg

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Eric, here is the same bird you inspected last month that flew on the M650, flew this past weekend at Mini Midwest Power on an M1297, same result as mine, fortunately John was able to recover the payload bay, unlike me, and able to post mortem the rocket and it appears pretty clear that it folded over on that short 2" coupler.

Unfortunate.



Yikes! Sorry to see your and John's Fusions go! Definitely a design flaw there. :oops::(
 

Frederocket

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Having not seen the original thread earlier, I decided to give my opinion.... A project with a 2" coupler separation shoulder would not make it past design review, much less build review and or allowed to be launched as a completed L-3 certification flight. If any LC3 or TAP would allow such a design, much less a flight, they need to go back to school, as their certification skill set is unacceptable. In addition, any kit manufacture advertising this kit as a acceptable L3 kit, with directions to build it as this one was built, (2" coupler shoulder), is taking liberties with the truth. Counting; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10....POST
 

firemanup

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Having not seen the original thread earlier, I decided to give my opinion.... A project with a 2" coupler separation shoulder would not make it past design review, much less build review and or allowed to be launched as a completed L-3 certification flight. If any LC3 or TAP would allow such a design, much less a flight, they need to go back to school, as their certification skill set is unacceptable. In addition, any kit manufacture advertising this kit as a acceptable L3 kit, with directions to build it as this one was built, (2" coupler shoulder), is taking liberties with the truth. Counting; 1, 2, 3, 4, 5, 6, 7, 8, 9, 10....POST

I certainly don't disagree, I did however think that maybe i was learning something new, as this was a "proven kit design"....

That along with the fact that the coupler is pinned by 6 rivets and not a moving coupler i was willing to give it a try, I think the coupler is a weak link with any side loading/wind shear and I am going to rebuild one, however I will redesign the av bay so that i have a minimum of 5" length on any joining couplers.

Take away that shortcoming, and find a fix and it's a pretty cool rocket for me in that it's very light and could easily then fly on K through M...slow and low up to high and fast.. I'm gonna give it another go.

Here is the build video, at 53 minutes even you can see this coupler being set in the body tube and it's short length...

 
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